| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Alakangas, Lena, et al.
(författare)
-
Project: Improve Resource Efficiency and Minimize Environmental Footprint
- 2016
-
Annan publikation (populärvet., debatt m.m.)abstract
- The REMinE project is organized in five work packages that comprise: detailedcharacterization and risk assessment of the mine wastes selected (WP2), identification of new processing methods for mine waste (WP3), characterization and risk assessment of the remaining residuals (WP4), outlining business opportunities and environmental impact in a conceptual model for sustainable mining (WP5). The project comprises case studies of historical mine wastes from three different European countries, namely Portugal, Romania and Sweden. The interdisciplinary research collaboration in this project is innovative in the sense that separation of minerals and extraction of metals not only are basedon technical and economic gain but also considers the environmental perspective.
|
|
| 5. |
- Andersson, Anton, et al.
(författare)
-
Characterization and Upgrading of a Low Zinc-Containing and Fine Blast Furnace Sludge : A Multi-Objective Analysis
- 2017
-
Ingår i: ISIJ International. - : The Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 57:2, s. 262-271
-
Tidskriftsartikel (refereegranskat)abstract
- Ore-based steelmaking generates a variety of residues including dusts, sludges and slags. Recycling of these residues within the process or via other applications is essential for sustainable production from both environmental and economic aspects. In blast furnace (BF) ironmaking, there are generally two residues leaving the gas cleaning equipment; namely, BF dust and BF sludge. Traditionally, the dust is recycled via the sinter or, in the case of pellet based BF, via cold bonded agglomerates and injection. As the main output of zinc from the BF is the top gas, the sludge has to be dezinced prior to recycling to prevent accumulation of zinc in the furnace. Although dezincing of BF sludge has been successfully accomplished using e.g., hydrocycloning, the studied sludges are generally coarse sized and high in zinc. Furthermore, information is lacking regarding the efficiency of separation of different hydrocyclone setups. In the present work, hydrocycloning of a fine sludge, with low zinc content, generated by a pellet based BF has been studied. The gas cleaning equipment used to produce the sludge was running a primary aerocyclone and a scrubber. A characterization of the sludge has been conducted together with an evaluation of the separation efficiency of the hydrocyclone in order to assess the hydrocyclone performance and limitations. Furthermore, the dezincing using the hydrocyclone has been compared to that of sulfuric acid leaching. The results suggest that 51 to 93% of the sludge can be recycled depending on the demand on zinc removal and the chosen dezincing route.
|
|
| 6. |
- Bergamo, Pedro A. de S.
(författare)
-
On the use of immersive technologies in the professional education of mineral processing
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- With the advance of technology, many educators started implementing immersive technologies like simulators and gamified learning applications to improve the trainings of process operators. However, it is noted that the minerals sector is significantly behind other industries, for instance, the chemical industry, especially when it comes to the evaluation of these types of trainings. Understanding how new technologies and concepts can improve the creation and evaluation of operator trainings, would perhaps create solutions for the lack of skilled operators in the mining sector, which is partly related to the challenge of evaluating time-dependent skills. In this scenario, this research aims to access the use of immersive technologies to increase the creation of operator talent in the minerals industry. In this context, an EU-funded network called “metalintelligence” exists. Its aim is to provide innovative research and equip a new generation of leaders in the minerals processing field providing lasting novel technological and training methods to build capacity in this growing area thus further establishing the EU’s leadership position in minerals processing. Hypothetically, the research in this field, backed by strong case studies, could provide valuable hints on how the trainings of operators could be made more efficient by using new technologies and concepts such as modelling and simulation and gamification. The study conducted within this thesis project can be divided into four parts, starting with a systematic review of how immersive technologies such as virtual reality (VR), educational games and simulation-based trainings have been used to teach different topics related to mining and mineral processing operations during the last 20 years. The current applications are mostly focused on hazard awareness and specific maneuvers of mining equipment, while only a few are related to the operation and management of the control rooms in mineral processing plants. During the review, it was noted that most papers found in the literature focus on the technical description of their solutions but fail to present an evaluation of the application by experts in the field. The review also found that further benefits can be achieved by employing tools like cloud solutions and gamification as these technologies can help with the collection of user data and improve the validation of technology-enhanced trainings. In the second part of this thesis, a case study is presented on how the current trainings of mineral process operators can benefit from immersive technologies. It involves the development and evaluation of a simulator-based training for froth flotation. The training was delivered to a group of operators at a greenfield process site and the analysis of the trainees’ evaluations were collected and discussed based on the first two levels of the Kirkpatrick evaluation model, a broadly used evaluation model. The reaction evaluation showed a strong satisfaction and a high learning perception from the trainees, while the learning evaluation, gathered with the help of the simulator, showed several weak spots in the training, especially when it came to teaching performance calculations. The disparity between the reaction and learning evaluations raises serious questions about evaluating trainings solely on the trainees’ feedback and goes against some principles of established evaluation methods such as Kirkpatrick’s. The third part of this study comprises the development of a training solution called “Minfloat”. It is an educational game developed in Unity3D focused on teaching the basic process behavior of froth flotation to operators and university students. It also describes the attempts to create a light-weight simulator core that could be run on a mobile device. After first testing a short-cut model, a model based on first principles was programmed and linked to the user interface. The game also includes an intelligent tutoring system (ITS) which presents concepts, examples, and questions pertinent to flotation performance calculations to the user. The principles of user experience (UX) design were used to produce assets (e.g., boxes, buttons, containers, and graphs) that could be re-used by other training developers, therefore promoting modularity, in a way that developers could use those to create their own educational games. The current game could be extended to basically every aspect of flotation, as also other mineral processes. In addition, the modules (such as assets, ITS, and graphs) could be re-used by other Unity3D developers to create trainings for topics in practically every process industry. The fourth and last part of the study involved the development of a questionnaire aiming to evaluate “Minfloat” in terms of overall quality, didactic efficacy, and inspiring character, besides having a better understanding of the target audience and outlook of the solution. To develop this questionnaire, the history of evaluation frameworks such as Kirkpatrick’s ‘Four levels’, Phillips’s ‘return on investment (ROI) based evaluation’ and Scriven’s ‘Goal-free evaluation’ are introduced to help clarifying the steps involved in assessing and evaluating a gamified educational solution like “Minfloat”.The questionnaire was applied to 25 experts in the minerals industry to access key aspects of the game-based training described earlier. From the results, three key lessons can be taken. The first is that users were, in general, satisfied with the game in terms of quality, efficacy and inspiring character. Second, users thought that the main target of the game should be university students, although novice industrial operators could also benefit from it. Third, the use of this short questionnaire, combined with the use of online forms, is a powerful tool for researchers who need a fast and efficient way to evaluate important aspects of a game and get feedback in written form.By analyzing the four parts of this research, some clear concluding benefits of the use of immersive technologies in operator training can be outlined. The first is that new engines such as Unity3D united with modelling and simulation, were proven to be powerful tools to create efficient, inspiring and non-expensive educational solutions for the process industry. Being a free software for personal or small companies, there is a big chance that, in the near future, engineering students will start using it to create their own educational trainings, and compete with larger companies which currently dominate that training market. Another contribution from this research is an evaluation form that provides training developers a way to get feedback for their application, improve their games or simulation-based trainings and produce more comprehensive articles about education in the minerals industry.The next step for this research would be to develop similar kinds of applications for other mineral beneficiation units and methods, such as comminution and hydrometallurgy. The game presented could even be expanded to teach the operation of an entire mineral processing plant. This way, university students and novice operators could learn and understand, in an inspiring way, important aspects of this type of operations, including material characterization, reagent usage, operational parameter setting, equipment design as well as financial and holistic operations of mineral processes. This development could revolutionize the teaching of mineral processes, the same way simulators leveled up the training of flight operators. However, this revolution will only occur if those immersive technologies are guided by the light of a proper and inexpensive evaluation, which will make sure that the technologies developed by academia are resonating in the same wavelength as the solutions of the industrial sector. Another aspect that immersive technologies could help with, is the declining rates of students entering university courses like mineral industry and geoscience. Digitalization solutions like the one described could help to inspire more students to choose a career in those fields, helping with the development of societies and their increasing needs for minerals.
|
|
| 7. |
- Bergamo, Pedro A. de S., et al.
(författare)
-
Simulation-based training and learning : A review on technology-enhanced education for the minerals industry
- 2022
-
Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 175
-
Tidskriftsartikel (refereegranskat)abstract
- There is a lack of skilled operators for mineral processing plants in the mining sector, which might be related to the challenge of creating trainings that addresses the operator’s daily work problems. In recent years, the use of simulator-based trainings as a tool to build competence has grown in many different fields. With the help of technologies like virtual reality, these tools have been demonstrated to increase awareness and the capability of workers when compared to traditional learning methods. In this paper, a review is presented on the development and application of such technologies in simulation-based training for the training of operators of the minerals industry in the last 20 years. Proposed next steps and new technologies with the potential of improving these applications are also discussed.
|
|
| 8. |
- Bergamo, Pedro A. de S., et al.
(författare)
-
Use of Kirkpatrick evaluation model in simulation-based trainings for the mining industry - A case study for froth flotation
- 2022
-
Ingår i: Minerals Engineering. - : Elsevier Ltd. - 0892-6875 .- 1872-9444. ; 188
-
Tidskriftsartikel (refereegranskat)abstract
- Trainings play a vital role in the transference of knowledge between skilled and novice operators in the mineral industry. Evaluation is an important part of those trainings, but many trainings rely solely on the trainees’ feedback. This paper presents how technology enhancement can help produce more effective training evaluations to the mineral industry. It describes a case study involving a froth flotation simulator-based training, including details of the simulation, user interface, and the training program. The training was delivered to sixteen mining operators and evaluated by both the traditional method (trainee's feedback) and with the simulation's learning evaluation. The feedback evaluation showed a high level of satisfaction with the learning results, while the learning evaluation showed a very different training outcome, putting established evaluation methods such as Kirckpatrick's “Four levels” into question. Correlations between the learning results and the operators’ personal information such as process work, and academic experience are also presented.
|
|
| 9. |
- Bielig, Tina, et al.
(författare)
-
Methodology for the process based acquisition and assessment of non-intended outputs in the mining industry
- 2007
-
Ingår i: CLEAN - Soil, Air, Water. - : Wiley. - 1863-0650 .- 1863-0669. ; 35:4, s. 370-377
-
Tidskriftsartikel (refereegranskat)abstract
- For the activities of the mining industry land, equipment, material, and energy are used. During operation material and energy flows such as overburden, dead rock, tailings, wastewater, exhaust air, dust, energy, abrasion, coolant and lubricant losses, are released. These released material and energy flows are nearly always without value for the raw material supply chain as they are not production targets. Instead, they have negative effects on the economy and ecology and are, therefore, referred to as non-intended. The knowledge of the quantities and qualities of these non-intended outputs as a function of the processes and their parameters is the basis for technical and economical measures. A methodology for the acquisition and assessment of the material and energy flows in the mining industry was developed and tested at the Technical University Berlin, Germany. For that purpose and based on a system analysis in different mines, all relevant material and energy flows were assigned to individual processes. Causal relationships, possible interactions, quantities, and qualities were examined as functions of system parameters. Finally, a technical and economic evaluation was performed.
|
|
| 10. |
- Bru, Kathy, et al.
(författare)
-
Comparative laboratory study of conventional and Electric Pulse Fragmentation (EPF) technologies on the performances of the comminution and concentration steps for the beneficiation of a scheelite skarn ore
- 2020
-
Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 150
-
Tidskriftsartikel (refereegranskat)abstract
- Electric Pulse Fragmentation (EPF) is an innovative technology that uses High-Voltage Pulsed Power (HVPP) for the selective comminution of a material. This paper aims to compare a beneficiation flowsheet including an EPF treatment in the comminution circuit to a conventional pathway where the EPF step was replaced by a series of jaw crushers. Tests were performed on a skarn ore containing scheelite as the main mineral of interest. This ore is characterized by a fine-grained mineralogy and represents a challenge to conventional comminution processing, requiring fine grinding to liberate the valuable minerals. Fine grinding has high energy requirements and generates large amounts of fines which can result in losses of the target mineral due to their removal before the concentration processes, especially in this case since scheelite is a brittle material.Comparison of EPF treatment to mechanical crushing with a similar product size P80 (i.e. 80% passing size) showed that the EPF treatment led to a significant increase in WO3 content and distribution in the 0/250 µm size fraction suggesting a pre-concentration aspect to EPF treatment. Moreover, a marked improvement of the grindability of the ore treated at a discharged energy of 9.1 kWh/t was observed with values of 10.6 kWh/t compared to 14.5 kWh/t when conventional treatment was used. Subsequent grinding and concentration steps confirmed the positive impacts of the fragmentation selectivity and pre-weakening effect of the EPF treatment. In particular, a reduction in fines production was observed after ball milling and a better concentrate grade was achieved for a similar recovery rate when an EPF treatment was included in the comminution pathway compared to the conventional one. These results confirm the potential of the EPF treatment for improving the performances of the beneficiation processes of this scheelite-bearing skarn ore.
|
|
| 11. |
- Chelgani, Saeed Chehreh, et al.
(författare)
-
A comparative study on the effects of dry and wet grinding on mineral flotation separation : a review
- 2019
-
Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854 .- 2214-0697. ; 8:5, s. 5004-5011
-
Forskningsöversikt (refereegranskat)abstract
- Water scarcity dictates to limit the use of water in ore processing plants particularly in arid regions. Since wet grinding is the most common method for particle size reduction and mineral liberation, there is a lack of understanding about the effects of dry grinding on downstream separation processes such as flotation. This manuscript compiles various effects of dry grinding on flotation and compares them with wet grinding. Dry grinding consumes higher energy and produces wider particle size distributions compared with wet grinding. It significantly decreases the rate of media consumption and liner wear; thus, the contamination of pulp for flotation separation is lower after dry grinding. Surface roughness, particle agglomeration, and surface oxidation are higher in dry grinding than wet grinding, which all these effects on the flotation process. Moreover, dry ground samples in the pulp phase correlate with higher Eh and dissolved oxygen concentration. Therefore, dry grinding can alter the floatability of minerals. This review thoroughly assesses various approaches for flotation separation of different minerals, which have been drily ground, and provides perspectives for further future investigations.
|
|
| 12. |
- Chipakwe, Vitalis, et al.
(författare)
-
A comparative study on the effect of chemical additives on dry grinding of magnetite ore
- 2020
-
Ingår i: South African Journal of Chemical Engineering. - : Elsevier. - 1026-9185. ; 34, s. 135-141
-
Tidskriftsartikel (refereegranskat)abstract
- Dry grinding as an alternative to wet grinding is one of Sweden's strategic research areas to promote dry beneficiation. However, dry grinding has remained unpopular due to its higher specific energy consumption (Ec), wider particle size distribution (PSD), difficult material handling, and purported effects on downstream processes. In this work, the effects of the new additives (Zalta™ GR20–587, Zalta™ VM1122, and Sodium hydroxide) employed as grinding aids (GA) on dry grinding and product characteristics of a magnetite ore were studied in light of possible downstream effects. The grinding efficiency of Magnetite increased after using GAs in comparison without the GAs; however, an optimal dosage exists for each of the chemical additives investigated. Comparing to grinding without GA, Zalta™ VM1122, a viscosity modifier was selected as the most effective GA where by using this GA; the Ec decreased by 31.1% from 18.0 to 12.4 kWh/t, the PSD became narrower and finer (the P80 decreasing from 181 to 142 µm), and the proportion of the particles (38–150 µm) increased from 52.5 to 58.3%. Zalta™ VM1122 resulted in increased surface roughness and minimum microstructural defects. Further, it was found that Zalta™ VM1122 resulted in similar zeta potentials and pH values for the product compared to grinding without GA. These comparable product properties are advantageous as they minimize any potential negative effects on all possible downstream processes such as flotation.
|
|
| 13. |
- Chipakwe, Vitalis, et al.
(författare)
-
A critical review on the mechanisms of chemical additives used in grinding and their effects on the downstream processes
- 2020
-
Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854 .- 2214-0697. ; 9:4, s. 8148-8162
-
Forskningsöversikt (refereegranskat)abstract
- Grinding aids (GAs) have been an important advent in the comminution circuits. Over the last few decades, in order to address the high energy consumption and scarcity of potable water for mineral processing, chemical additives have become a promising alternative. Using GAs can have some advantages such as enhancing grinding efficiency, reducing water usage, improving material flowability, and narrowing the particle size distribution of the grinding products. A study on the effect of GAs on size reduction units is crucial for the beneficiation value chain of minerals and the impact on downstream processes. However, our understanding of the effects of these materials on the particle size reduction is quite limited. This article analyses the literature, which used GAs and provides a comprehensive review of their applications in the ore beneficiation processes. The outcomes of this investigation indicated that the current understanding on the mechanism of GA effects focuses only on their impacts on the product fineness and size distribution, and neglecting the aspect of energy expended and physicochemical environment. The application of GAs is mainly for rationalisation of energy where the type of reagent, pH, and ionic strength of the grinding environment is important. Gaps in knowledge of GAs are discussed in the context of addressing their use in the mineral industry, considering the mechanism of their effect, effect on grinding efficiency, and effect on the downstream processes. Addressing these gaps will pave the way for the application of GAs in improving size reduction efficiencies, which ultimately reduces environmental impacts.
|
|
| 14. |
- Chipakwe, Vitalis
(författare)
-
Application of Chemical Additives in Minerals Beneficiation – Implications on Grinding and Flotation Performance
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The application of chemical additives, known as grinding aids (GAs), dates to 1930 in the cement industry. Unlike the cement industry, where the use of GAs is in the final processing step, it could be one of the first processing steps in ore beneficiation. Further to grinding performance, the successful application of GAs requires understanding the effect on ground products and possible interaction of the GAs in view of downstream processes. Understanding and controlling any GA-separation reagent interactions is critical to ensure that the required downstream process efficiency and integrity of the entire value chain are maintained. In this thesis, the effect of selected chemical additives on dry grinding performance and product properties is investigated. Second, the effect of the additives on surface properties and pulpchemistry, together with the resulting behavior in subsequent froth flotation separation, is investigated.The use of environmentally benign and sustainable alternatives to conventional surfactants is growing within mineral processing. To this end, a polysaccharide-based grinding aid (PGA) (natural polymer) together with a polyacrylic acid-based grinding aid (AAG) (synthetic polymer) were used as grinding aids. The effect of PGA and AAG at varying concentrations was investigated with respect to energy consumption, particle size distribution, BET surface area, roughness, and rheology. The resulting grinding parameters were correlated with the measured rheology indices from the automated FT4 powder rheometer. Moreover, the effect of the GAs on the flotation of quartz from magnetite was investigated using an artificial mixture ore. Zeta potentials, stability measurement, adsorption test, and FTIR analyzes were performed to understand the mechanisms of surface interaction and adsorption.The grinding results indicated that the application of GAs reduced energy consumption by up to 31.1 % and gave a finer-uniform product size, higher specific surface area, and increased surface roughness compared to grinding without. Further studies on powder rheology indicated that the GAs used resulted in improved material flowability compared to grinding without additives. There was a strong correlation (r > 0.93) between the grinding and the flow parameters. Flotation tests on pure samples illustrated that PGA has beneficial effects on magnetite depression (with negligible impact on quartz floatability) through reverse flotation separation. The benefits were further confirmed by the flotation of the artificial mixture in the presence of PGA. The PGA adsorption mechanism was mainly through physical interaction based on UV-Vis spectra, zeta potential tests, Fourier transform infrared spectroscopy (FT-IR), and stability analyses. Additionally, single mineral flotation tests indicated that AAG enhanced quartz collection with minimal effect on magnetite. Mixed mineral flotation revealed that, by using AAG, comparable metallurgical performance could be achieved at a lower collector dosage. The zeta potentials and stability measurements showed that AAG shifts the potential, thus improving the stability and dispersion of the suspension. Adsorption tests revealed that AAG adsorbed on both quartz and magnetite, with the former having a higher capacity. Fourier transform infrared spectroscopy showed that the interaction between AAG and the minerals occurs via a physical interaction.The findings illustrate that GAs improved grinding efficacy at optimum dosage and enhanced product properties. Furthermore, the predominant mechanism of GAs is based on the alteration of rheological properties. Importantly, the feasibility of using GAs to improve grinding performance has been demonstrated with secondary beneficial effects on flotation.
|
|
| 15. |
- Chipakwe, Vitalis, et al.
(författare)
-
Beneficial effects of a polysaccharide-based grinding aid on magnetite flotation: a green approach
- 2022
-
Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Grinding is the most energy-intensive step in mineral beneficiation processes. The use of grinding aids (GAs) could be an innovative solution to reduce the high energy consumption associated with size reduction. Surprisingly, little is known about the effects of GAs on downstream mineral beneficiation processes, such as flotation separation. The use of ecofriendly GAs such as polysaccharide-based materials would help multiply the reduction of environmental issues in mineral processing plants. As a practical approach, this work explored the effects of a novel polysaccharide-based grinding aid (PGA) on magnetite's grinding and its reverse flotation. Batch grinding tests indicated that PGA improved grinding performance by reducing energy consumption, narrowing particle size distribution of products, and increasing their surface area compared to grinding without PGA. Flotation tests on pure samples illustrated that PGA has beneficial effects on magnetite depression (with negligible effect on quartz floatability) through reverse flotation separation. Flotation of the artificial mixture ground sample in the presence of PGA confirmed the benefits, giving a maximum Fe recovery and grade of 84.4 and 62.5%, respectively. In the absence of starch (depressant), PGA resulted in a separation efficiency of 56.1% compared to 43.7% without PGA. The PGA adsorption mechanism was mainly via physical interaction based on UV–vis spectra, zeta potential tests, Fourier transform infrared spectroscopy (FT-IR), and stability analyses. In general, the feasibility of using PGA, a natural green polymer, was beneficial for both grinding and reverse flotation separation performance.
|
|
| 16. |
- Chipakwe, Vitalis
(författare)
-
Comparative Study of Chemical Additives Effects on Dry Grinding Performance
- 2021
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The application of chemical additives, known as grinding aids (GA), dates back to 1930 in the cement industry. As opposed to the cement industry, where the use of GAs is on the final processing step, it could be one of the first process steps in ore beneficiation. A few investigations addressed the GA applications in ore dressing; therefore, further studies are required to better understand the GA effects on the product properties and downstream separation processes. This thesis undertakes a comparative study on the dry grinding of magnetite and the resulting product characteristics with and without GAs. The main aim is to reduce energy consumption and to address some of the challenges associated with dry processing. The effects of GAs on the dry batch ball milling of magnetite were examined to analyze the energy consumption (Ec), particle size distribution, flow properties, bulk properties, surface morphology, particle fineness, and surface chemistry of products. Their effects on the ground product were systematically explored by sieve analysis, powder rheology, BET surface measurements, optical microscopy analysis, and zeta potential measurements. Compared with the absence of GAs, the dry grinding efficiency of magnetite increased after using GAs; however, an optimal dosage exists based on the GA type. Among GAs which considered in this investigation (Zalta™ GR20-587 (Commercial GA) and Zalta™ VM1122 (Commercial viscosity aid) as well as sodium hydroxide), Zalta™ VM1122, a polysaccharide-based additive, was the most effective GA where by using this GA; the Ec decreased by 31.1% from 18.0 to 12.4 kWh/t. The PSD became narrower and finer (P80 decreasing from 181 to 142 µm), and the proportion of the particles (38–150 µm) increased from 52.5 to 58.3%. In general, the results reveal that at sufficient GA dosages, they reduce the average particle size, increase the specific surface area, and narrow the particle size distribution. However, an excessive amount of GAs could be detrimental to the grinding performance. Further studies on powder rheology indicated that the used GAs resulted in improved material flowability compared to grinding without additives (in the examined dosage range). The rheology measurements by the FT4 Powder Rheometer showed strong linear correlations between basic flow energy, specific energy, and the resulting work index when GAs was considered for grinding. There was a strong correlation between the grinding parameters and flow parameters (r > 0.93). These results confirmed the effect of GA on ground particles' flowability. Zalta™ VM1122 showed the best performance with 38.8% reduction of basic flow energy, 20.4 % reduction of specific energy, 24.6% reduction of aerated basic flow energy, and 38.3% reduction of aerated energy. The present investigation showed that the predominant mechanism of GAs is based on the alteration of rheological properties. Further investigation on the surface properties showed that using GAs could increase the surface roughness, which is beneficial for downstream processes such as froth flotation. Zalta™ VM1122 resulted in increased surface roughness and minimum microstructural defects from the optical microscope images. Furthermore, Zalta™ VM1122 (non-ionic) resulted in similar zeta potentials and pH values for the product compared to experiments without GA. These comparable product properties are advantageous as they minimize any potential negative effects on all possible downstream processes.
|
|
| 17. |
- Chipakwe, Vitalis, et al.
(författare)
-
Effects of Chemical Additives on Rheological Properties of Dry Ground Ore - a Comparative Study
- 2022
-
Ingår i: Mineral Processing and Extractive Metallurgy Review. - : Taylor & Francis. - 0882-7508 .- 1547-7401. ; 43:3, s. 380-389
-
Tidskriftsartikel (refereegranskat)abstract
- It is well documented that chemical additives (grinding aid “GA”) during grinding can increase mill throughput, reduce water and energy consumption, narrow the particle size distribution of products, and improve material flowability. These advantages have been linked to their effects on the rheology, although there is a gap in understanding GA effectiveness mechanism on the flow properties. The present study aims to fill this gap using different GAs (Zalta™ GR20-587, Zalta™ VM1122, and sodium hydroxide) through batch grinding experiments of magnetite ore and addressing the mechanisms of their effects on the rheology by an FT4 Powder Rheometer as a unique system. Experimental results showed that GA improved grinding efficiency (energy consumption and product fineness), which were well-correlated with basic flow energy, specific energy, aerated basic flow energy, and aerated energy. Moreover, the rheometry measurement showed strong linear correlations between basic flow energy, specific energy, and the resulting work index when GAs was considered for grinding, which confirmed the effect of GA on ground particles’ flowability. Zalta™ VM1122, a polysaccharide-based grinding aid, showed the best performance with 38.8% reduction of basic flow energy, 20.4% reduction of specific energy, 24.6% reduction of aerated basic flow energy, and 38.3% reduction of aerated energy. It also showed the strongest correlation between the grinding parameters and flow parameters (r > 0.93). The present investigation shows a strong indication that the predominant mechanism of GAs is based on the alteration of rheological properties and identify Zalta™ VM1122 as the best GA.
|
|
| 18. |
- Chipakwe, Vitalis, et al.
(författare)
-
Exploring the effect of a polyacrylic acid-based grinding aid on magnetite-quartz flotation separation
- 2023
-
Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 305
-
Tidskriftsartikel (refereegranskat)abstract
- It is well documented that the use of grinding aids (GAs) can reduce milling energy consumption. However, the impact of GAs on downstream processes must be addressed in view of complex processes such as froth flotation separation. This study investigates the effects of polyacrylic-based grinding aids (Zalta™ GR20-587: AAG) on the grinding performance and quartz flotation from magnetite. Various AAG dosages and conditions were examined. The grinding results showed lower energy consumption and a finer, more uniform product size with roughened surfaces for AAG compared to grinding without the grinding aid. Flotation tests of single pure minerals showed that AAG enhanced quartz collection with minimal effect on magnetite. Mixed mineral flotation showed that by using AAG, Fe recovery of 92.1 % and 64.5 % Fe grade could be achieved with a lower collector dosage of 100 g/t compared to 200 g/t in the absence of AAG. Zeta potentials and stability measurements showed that AAG shifts the potential, thus improving the stability and dispersion of the suspension. Adsorption tests illustrated that AAG adsorbed on both quartz and magnetite, the former having a higher capacity. FTIR indicated the physisorption interaction between AAG and the minerals. Therefore, the presence of AAG not only improved grinding efficiency but could potentially decrease the amount of collector required to achieve comparable metallurgical performance.
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
|
|
| 24. |
- Ghorbani, Yousef, et al.
(författare)
-
Rethinking Mineral Processing and Extractive Metallurgy Approaches to Ensure a Sustainable Supply of High-tech and Critical Raw Materials
- 2021
-
Ingår i: Rare Metal Technology 2021. - Cham : Springer. ; , s. 173-186
-
Konferensbidrag (refereegranskat)abstract
- Raw materials (RM) are crucial for maintaining our standard of living internationally. The fourth industrial revolution and the energy transition are reliant on access to various RMs. High-tech RMs are usually extracted as by-products from ore deposits. To increase the production of rare high-tech RM, it is essential to modify the existing bulk RM production processes and utilize partial, secondary, or waste streams. This study aims to present and discuss the necessities of redefining the concept and scope in mineral processing and extractive metallurgy approaches in order to secure a sustainable supply of high-tech and critical raw material (CRM) for the economy in modern society. We introduce a list of paths and trends for developing future concepts and methods in mineral processing and extractive metallurgy in pursuit of the sustainability of high-tech CRMs from all resources.
|
|
| 25. |
- Gruhn, Günter, et al.
(författare)
-
Development of an object-oriented simulation system for complex solids processes
- 1997
-
Ingår i: Computers and Chemical Engineering. - 0098-1354 .- 1873-4375. ; 21, s. S187-S192
-
Tidskriftsartikel (refereegranskat)abstract
- This contribution focuses on the development of SolidSim, an object-oriented, sequential-modular simulator adopted to the special requirements of steady-state solids processes. The conceptual design of the program system and implementational issues concerning process streams and unit operation models are outlined. Results from first test runs for different solids processes are presented.
|
|
| 26. |
|
|
| 27. |
- Guntoro, Pratama Istiadi, 1993-, et al.
(författare)
-
3D Ore Characterization as a Paradigm Shift for Process Design and Simulation in Mineral Processing
- 2021
-
Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 166:8, s. 384-389
-
Tidskriftsartikel (refereegranskat)abstract
- Current advances and developments in automated mineralogy have made it a crucial key technology in the field of process mineralogy, allowing better understanding and connection between mineralogy and the beneficiation process. The latest developments in X‑ray micro-computed tomography (µCT) have shown a great potential to let it become the next-generation automated mineralogy technique. µCT’s main benefit lies in its capability to allow 3D monitoring of the internal structure of the ore sample at resolutions down to a few hundred nanometers, thus excluding the common stereological error in conventional 2D analysis. Driven by the technological and computational progress, µCT is constantly developing as an analysis tool and successively it will become an essential technique in the field of process mineralogy. This study aims to assess the potential application of µCT systems, for 3D ore characterization through relevant case studies. The opportunities and platforms that µCT 3D ore characterization provides for process design and simulation in mineral processing are presented.
|
|
| 28. |
- Guntoro, Pratama Istiadi, 1993-, et al.
(författare)
-
Application of machine learning techniques in mineral phase segmentation for X-ray microcomputed tomography (µCT) data
- 2019
-
Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 142
-
Tidskriftsartikel (refereegranskat)abstract
- X-ray microcomputed tomography (µCT) offers a non-destructive three-dimensional analysis of ores but its application in mineralogical analysis and mineral segmentation is relatively limited. In this study, the application of machine learning techniques for segmenting mineral phases in a µCT dataset is presented. Various techniques were implemented, including unsupervised classification as well as grayscale-based and feature-based supervised classification. A feature matching method was used to register the back-scattered electron (BSE) mineral map to its corresponding µCT slice, allowing automatic annotation of minerals in the µCT slice to create training data for the classifiers. Unsupervised classification produced satisfactory results in terms of segmenting between amphibole, plagioclase, and sulfide phases. However, the technique was not able to differentiate between sulfide phases in the case of chalcopyrite and pyrite. Using supervised classification, around 50–60% of the chalcopyrite and 97–99% of pyrite were correctly identified. Feature based classification was found to have a poorer sensitivity to chalcopyrite, but produced a better result in segmenting between the mineral grains, as it operates based on voxel regions instead of individual voxels. The mineralogical results from the 3D µCT data showed considerable difference compared to the BSE mineral map, indicating stereological error exhibited in the latter analysis. The main limitation of this approach lies in the dataset itself, in which there was a significant overlap in grayscale values between chalcopyrite and pyrite, therefore highly limiting the classifier accuracy.
|
|
| 29. |
- Guntoro, Pratama Istiadi, 1993-, et al.
(författare)
-
Development and experimental validation of a texture-based 3D liberation model
- 2021
-
Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 164
-
Tidskriftsartikel (refereegranskat)abstract
- Prediction of mineral liberation is one of the key steps in establishing a link between ore texture and its processing behavior. With the rapid development of X-ray Microcomputed Tomography (µCT), the extension of liberation modeling into 3D realms becomes possible. Liberation modeling allows for the generation of particle population from 3D texture data in a completely non-destructive manner. This study presents a novel texture-based 3D liberation model that is capable of predicting liberation from 3D drill core image acquired by µCT. The model takes preferential, phase-boundary, and random breakage into account with differing relative contributions to the liberation depending on the ore texture itself. The model was calibrated using experimental liberation data measured in 3D µCT. After calibration, the liberation model was found to be capable of explaining on average of around 84% of the variance in the experimental liberation data. The generated particle population can be used for particle-based process simulation to evaluate the process responses of various ore textures subjected to various modes of breakage.
|
|
| 30. |
- Guntoro, Pratama Istiadi, 1993-, et al.
(författare)
-
Textural Quantification and Classification of Drill Cores for Geometallurgy: Moving Toward 3D with X-ray Microcomputed Tomography (µCT)
- 2020
-
Ingår i: Natural Resources Research. - : Springer. - 1520-7439 .- 1573-8981. ; 29:6, s. 3547-3565
-
Tidskriftsartikel (refereegranskat)abstract
- Texture is one of the critical parameters that affect the process behavior of ore minerals. Traditionally, texture has been described qualitatively, but recent works have shown the possibility to quantify mineral textures with the help of computer vision and digital image analysis. Most of these studies utilized 2D computer vision to evaluate mineral textures, which is limited by stereological error. On the other hand, the rapid development of X-ray microcomputed tomography (µCT) has opened up new possibilities for 3D texture analysis of ore samples. This study extends some of the 2D texture analysis methods, such as association indicator matrix (AIM) and local binary pattern (LBP) into 3D to get quantitative textural descriptors of drill core samples. The sensitivity of the methods to textural differences between drill cores is evaluated by classifying the drill cores into three textural classes using methods of machine learning classification, such as support vector machines and random forest. The study suggested that both AIM and LBP textural descriptors could be used for drill core classification with overall classification accuracy of 84–88%.
|
|
| 31. |
- Guntoro, Pratama Istiadi, 1993-, et al.
(författare)
-
Use of X-ray Micro-computed Tomography (µCT) for 3-D Ore Characterization : A Turning Point in Process Mineralogy
- 2019
-
Ingår i: IMCET 2019 - Proceedings of the 26th International Mining Congress and Exhibition of Turkey. - : Baski. ; , s. 1044-1054
-
Konferensbidrag (refereegranskat)abstract
- In recent years, automated mineralogy has become an essential enabling technology in the field of process mineralogy, allowing better understanding between mineralogy and the beneficiation process. Recent developments in X-ray micro-computed tomography (μCT) as a non-destructive technique have indicated great potential to become the next automated mineralogy technique. μCT’s main advantage lies in its ability to allow 3-D monitoring of internal structure of the ore at resolutions down to a few hundred nanometers, thereby eliminating the stereological error encountered in conventional 2-D analysis. Driven by the technological and computational progress, the technique is continuously developing as an analysis tool in ore characterization and subsequently it foreseen thatμCT will become an indispensable technique in the field of process mineralogy. Although several software tools have been developed for processing μCT dataset, but the main challenge in μCT data analysis remains in the mineralogical analysis, where μCT data often lacks contrast between mineral phases, making segmentation difficult. In this paper, an overview of some current applications of μCT in ore characterization is reviewed, alongside with it potential implications to process mineralogy. It also describes the current limitations of its application and concludes with outlook on the future development of 3-D ore characterization.
|
|
| 32. |
- Guntoro, Pratama Istiadi, 1993-
(författare)
-
X-ray microcomputed tomography (µCT) as a potential tool in Geometallurgy
- 2019
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, automated mineralogy has become an essential tool in geometallurgy. Automated mineralogical tools allow the acquisition of mineralogical and liberation data of ore particles in a sample. These particle data can then be used further for particle-based mineral processing simulation in the context of geometallurgy. However, most automated mineralogical tools currently in application are based on two-dimensional (2D) microscopy analysis, which are subject to stereological error when analyzing three-dimensional(3D) object such as ore particles. Recent advancements in X-ray microcomputed tomography (µCT) have indicated great potential of such system to be the next automated mineralogical tool. µCT's main advantage lies on its ability in monitoring 3D internal structure of the ore at resolutions down to few microns, eliminating stereological error obtained from 2D analysis. Aided with the continuous developments of computing capability of 3D data, it is only the question of time that µCT system becomes an interesting alternative in automated mineralogy system.This study aims to evaluate the potential of implementing µCT as an automated mineralogical tool in the context of geometallurgy. First, a brief introduction about the role of automated mineralogy in geometallurgy is presented. Then, the development of µCT system to become an automated mineralogical tool in the context of geometallurgy andprocess mineralogy is discussed (Paper 1). The discussion also reviews the available data analysis methods in extracting ore properties (size, mineralogy, texture) from the 3D µCT image (Paper 2). Based on the review, it was found that the main challenge inperforming µCT analysis of ore samples is the difficulties associated to the segmentation of the mineral phases in the dataset. This challenge is adressed through the implementation of machine learning techniques using Scanning Electron Microscope (SEM) data as a reference to differentiate the mineral phases in the µCT dataset (Paper 3).
|
|
| 33. |
- Guntoro, Pratama Istiadi, 1993-
(författare)
-
X-ray microcomputed tomography (µCT) as a potential tool in particle-based geometallurgy
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, automated mineralogy has become an essential tool in geometallurgy. Automated mineralogical tools allows the acquisition of mineralogical, textural, and liberation information of ore samples. Such information is essential in the context of geometallurgy where it is needed for estimating the process response of the ores. Most automated mineralogical tools currently in application are based on two-dimensional (2D) microscopy analysis, which are subject to stereological error when analyzing three-dimensional (3D) object such as ore particles. Recent advancements in X-ray microcomputed tomography (μCT) have indicated great potential of such system to be the next automated mineralogical tool. μCT’s main advantage lies in its ability in monitoring 3D internal structure of the ore at resolutions down to few microns, eliminating stereological error obtained from 2D analysis. Aided with the continuous developments of computing capability of 3D data, it is only the question of time that μCT system becomes an interesting alternative automated mineralogical tool for ore characterization.This study systematically evaluates the applicability of μCT as an alternative tool for ore characterization in the context of geometallurgy. The focus has been to assess the potential strengths of 3D data generated from μCT as well as how such data can offer a new perspective in characterizing the ore. Some of the limitations of 3D μCT data in describing the ore were also discussed, with alternative methods proposed to address these limitations. The main hypothesis of the study is that 3D data generated from μCT can be of a value in a geometallurgical program. This study has been conducted in three different parts in order to systematically test the hypothesis. The first part of the study evaluated the use of μCT to obtain mineralogical characteristics of the ore. Mineralogy of the ore is the cornerstone information needed to proceed with further characterization of the ore. It is therefore important to establish whether μCT are capable to obtain such information. The study demonstrated the well-known limitation of μCT, namely its difficulty when dealing with minerals of similar attenuation. The study demonstrated how machine-learning based methods complemented with 2D data from automated mineralogy could address the limitation.The capability of μCT for ore texture characterization was evaluated in the second part of the study. The main strength of μCT for core scanning is highlighted in the study, in which the possibility of using μCT for automated drill core recognition was demonstrated. Some of the popular texture analysis methods in 2D such as Local Binary Pattern (LBP) and Association Index Matrix (AIM) were extended to 3D in order to capture the textural pattern in drill core samples. Furthermore, a classification scheme based on these textural characteristics was devised for the automated recognition of the drill cores. An accuracy of 84-88% was achieved in the classification scheme, illustrating the potential of μCT for such task.The last part of the study concerns the use of μCT for mineral liberation modeling. Combining both mineralogical and textural information obtained from the previous parts of the study, a liberation model to forecast particle population from the 3D ore texture was created. The model was based on various breakage types such as preferential, phase boundary, and random breakage. The contribution of each breakage type to the final particle population could then be adjusted with actual particles produced from experimental comminution. Accurate forecasting of particle population is one of the key componentin the particle-based geometallurgy, in which the particle carries the ore characteristics to the beneficiation process. Utilizing these particles in a process modeling and simulation would give some idea about the process response of the ore. The integration of 3D data from μCT with the liberation model could potentially complete the link from ore characteristics to the process behavior in the framework of particle-based geometallurgy.Combination of these three parts of the study can open up a 3D path of particle-based geometallurgy. The study has demonstrated the efficient extraction of crucial ore characteristics such as texture, mineralogy, and mineral liberation using μCT. Key limitations and potential measures to address them have also been discussed in the study. Coupled with a framework for process simulation using such ore characteristics as an input, the 3D path of particle-based geometallurgy can be realized. Future research should be dedicated to develop such framework, as the establishment of μCT as an alternative ore characterization tool should also be motivated by from the downstream processes, i.e.whether the 3D μCT data can unlock a new perspective in process modeling and simulation compared to the conventional 2D data. This new perspective can help to build more accurate process prediction and production forecasting, which can ultimately guide the decision-making process for efficient resource management as the essential core of a geometallurgical program.
|
|
| 34. |
- Guntoro, Pratama Istiadi, 1993-, et al.
(författare)
-
X-ray Microcomputed Tomography (µCT) for Mineral Characterization : A Review of Data Analysis Methods
- 2019
-
Ingår i: Minerals. - Basel, Switzerland : MDPI. - 2075-163X. ; 9:3
-
Tidskriftsartikel (refereegranskat)abstract
- The main advantage of X-ray microcomputed tomography (µCT) as a non-destructive imaging tool lies in its ability to analyze the three-dimensional (3D) interior of a sample, therefore eliminating the stereological error exhibited in conventional two-dimensional (2D) image analysis. Coupled with the correct data analysis methods, µCT allows extraction of textural and mineralogical information from ore samples. This study provides a comprehensive overview on the available and potentially useful data analysis methods for processing 3D datasets acquired with laboratory µCT systems. Our study indicates that there is a rapid development of new techniques and algorithms capable of processing µCT datasets, but application of such techniques is often sample-specific. Several methods that have been successfully implemented for other similar materials (soils, aggregates, rocks) were also found to have the potential to be applied in mineral characterization. The main challenge in establishing a µCT system as a mineral characterization tool lies in the computational expenses of processing the large 3D dataset. Additionally, since most of the µCT dataset is based on the attenuation of the minerals, the presence of minerals with similar attenuations limits the capability of µCT in mineral segmentation. Further development on the data processing workflow is needed to accelerate the breakthrough of µCT as an analytical tool in mineral characterization.
|
|
| 35. |
- Jannesar Niri, Anahita, et al.
(författare)
-
Sustainability challenges throughout the electric vehicle battery value chain
- 2024
-
Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 191
-
Forskningsöversikt (refereegranskat)abstract
- The global commitment to decarbonizing the transport sector has resulted in an unabated growth in the markets for electric vehicles and their batteries. Consequently, the demand for battery raw materials is continuously growing. As an illustration, to meet the net-zero emissions targets, the electric vehicle market demand for lithium, cobalt, nickel, and graphite will increase 26-times, 6-times, 12-times, and 9-times respectively between 2021 and 2050. There are diverse challenges in meeting this demand, requiring the world to embrace technological and knowledge advancements and new investments without provoking conflicts between competing goals. The uncertainties in a sustainable supply of battery minerals, environmental, social and governance complexities, and geopolitical tensions throughout the whole battery value chain have shaped the global and regional concerns over the success of transport decarbonization. Here, focusing on the entire value chain of electric vehicle batteries, the approaches adopted by regulatory agencies, governments, mining companies, vehicle and battery manufacturers, and all the other stakeholders are evaluated. Bringing together all these aspects, this literature review broadens the scope for providing multifaceted solutions necessary to optimize the goal of transport decarbonization while upholding sustainability criteria. Consolidating the previously fragmented information, a solid foundation for more in-depth research on existing difficulties encountered by governmental and industrial actors is created. The outcomes of this study may serve as a baseline to develop a framework for a climate smart and resource efficient supply of batteries considering the unique impacts of individual players.
|
|
| 36. |
- Kappert, Kai, et al.
(författare)
-
Antioxidants relieve phosphatase inhibition and reduce PDGF signaling in cultured VSMCs and in restenosis
- 2006
-
Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - 1079-5642 .- 1524-4636. ; 26:12, s. 2644-2651
-
Tidskriftsartikel (refereegranskat)abstract
- Objective - Growth factor- and reactive oxygen species (ROS)-induced activation of VSMCs is involved in vascular disease. This study investigates whether inhibitory oxidation of protein tyrosine phosphatases (PTPs) contributes to signaling in VSMCs in vitro and in vivo, and analyzes whether ROS- and growth factor-dependent vascular smooth muscle cell (VSMC) signaling is blunted by antioxidants that are able to activate oxidized PTPs. Methods and Results - Signaling induced by H2O2 and platelet-derived growth factor (PDGF) was analyzed in VSMCs with or without the antioxidants N-acetyl-cysteine (NAC) and tempol. Effects of antioxidants on PDGF-stimulated chemotaxis and proliferation were determined. In vivo effects of antioxidants were analyzed in the rat carotid balloon-injury model, by analyzing neointima formation, cell proliferation, PDGF beta-receptor status, and PTP expression and activity. NAC treatment prevented H2O2-induced PTP inhibition, and reduced H2O2-and ligand-induced PDGF beta-receptor phosphorylation, PDGF-induced proliferation, and chemotaxis of VSMCs. Antioxidants inhibited neointima formation and reduced PDGF receptor phosphorylation in the neointima and also increased PTP activity. Conclusion - PTP-inhibition was identified as an intrinsic component of H2O2-and PDGF-induced signaling in cultured VSMCs. The reduction in PDGF beta-receptor phosphorylation in vivo, and the increase in PTP activity, by antioxidants indicate activation of oxidized PTPs as a previously unrecognized mechanism for the antirestenotic effects of antioxidants. The findings thus suggest, in general terms, reactivation of oxidized PTPs as a novel antirestenotic strategy.
|
|
| 37. |
- Koch, Pierre-Henri, 1988-, et al.
(författare)
-
Automated drill core mineralogical characterization method for texture classification and modal mineralogy estimation for geometallurgy
- 2019
-
Ingår i: Minerals Engineering. - Amsterdam : Elsevier. - 0892-6875 .- 1872-9444. ; 136, s. 99-109
-
Tidskriftsartikel (refereegranskat)abstract
- In geometallurgy, a process model operating at the mineral liberation level needs quantitative textural information about the ore. The utilization of this information within process modeling and simulation will increase the quality of the predictions.In this study, descriptors derived from color images and machine learning algorithms are used to group drill core intervals into textural classes and estimate mineral maps by automatic pixel classification. Different descriptors and classifiers are compared, based on their accuracy and capacity to be automated. Integration of the classifier approach with mineral processing simulation is also demonstrated. The quantification of textural information for mineral processing simulation introduced new tools towards an integrated information flow from the drill cores to a geometallurgical model.The approach has been verified by comparing traditional geological texture classification against the one obtained from automatic methods. The tested drill cores are sampled from a porphyry copper deposit located in Northern Sweden.
|
|
| 38. |
- Koch, Pierre-Henri, 1988-
(författare)
-
Computational methods and strategies for geometallurgy
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- At the interface of geology and mineral processing, geometallurgy is a powerful tool for enhancingresource efficiency. A spatial model that represents the ore body in terms ofmineralogyand physical properties is combined with a process model that describes the concentrationprocess. The performance of a given ore in the process is computed in terms of gradeand recovery of the mineral of interest in the concentrate, but also the presence of potentialpenalty elements and energy costs. The inclusion of ore performance indicators in a blockmodel yields a geometallurgical model that considers the variations in an ore body.Progress has been made in recent years to list and study different processing options interms of data requirements and implementation costs. While providing useful data, littleadvance was made to guide decision-making and to handle uncertainty. The objective has,therefore, been to develop, choose and validate computational methods that suggest optimaldecisions in the scope of geometallurgical strategies for an iron ore and a porphyry copperdeposit.The selected approach is based on an analysis of structure and regularity fromthe ore blockdown to the mineral grains. By selecting the appropriate mathematical tool for each scale,the dimension of the data is reduced and the different scales are then taken into account inmaking decisions. Methods introduced for dimension reduction include machine learningmodels, statistical models and spectral descriptors. The decision models rely on stochasticmulti-armed bandits which are a form of reinforcement learning. The presentation of thedifferent models proceeds by zooming in from coarse scale to fine scale then taking a stepback and analyze the implications. Data that was collected during sampling campaigns andindustrial plant surveys is used to design and verify the proposedmodels.iWith regard to the dimension reduction problem, results showed the method’s ability toclassify mineral textures and identify mineral phases with more than 90 percent accuracy onthe selected data sets of optical images and incorporate different physical properties into ageometallurgical ore type classification. Decision results showed that strategies in the case ofa feed grade control or when different ore types were identified, resulted in a twofold increaseof a reward function which is either Boolean (the product fulfills quality requirements ornot), or continuous (an economic objective). The cumulative value of the reward functionmeasured the optimality of a processing strategy. Quantitative methods were introduced toevaluate ore classification as well as geometallurgical strategies.The achieved results suggest the introduction of these computationalmethods in the practiceof geometallurgy. The increased knowledge of different ore type performances and appropriatemodels lead to optimal decisions for improved resource efficiency along the ore valuechain. This is achieved by bothmaximizing profit and decreasing environmental impact, forexample by choosing processing routes that minimize energy consumption.
|
|
| 39. |
- Koch, Pierre-Henri, et al.
(författare)
-
How to Build a Process Model in a Geometallurgical Program?
- 2015
-
Ingår i: Mineral Resources in a Sustainable World. - 9782855550664 ; , s. 1419-1422
-
Konferensbidrag (refereegranskat)abstract
- This work presents a literature review on ways to acquire relevant experimental data for the process model of a geometallurgical program. It identifies the needs in several unit models and proposes ideas for future developments
|
|
| 40. |
- Koch, Pierre-Henri, 1988-
(författare)
-
Particle generation for geometallurgical process modeling
- 2017
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A geometallurgical model is the combination of a spatial model representing an ore deposit and a process model representing the comminution and concentration steps in beneficiation. The process model itself usually consists of several unit models. Each of these unit models operates at a given level of detail in material characterization - from bulk chemical elements, elements by size, bulk minerals and minerals by size to the liberation level that introduces particles as the basic entity for simulation (Paper 1).In current state-of-the-art process simulation, few unit models are defined at the particle level because these models are complex to design at a more fundamental level of detail, liberation data is hard to measure accurately and large computational power is required to process the many particles in a flow sheet. Computational cost is a consequence of the intrinsic complexity of the unit models. Mineral liberation data depends on the quality of the sampling and the polishing, the settings and stability of the instrument and the processing of the data.This study introduces new tools to simulate a population of mineral particles based on intrinsic characteristics of the feed ore. Features are extracted at the meso-textural level (drill cores) (Paper 2), put in relation to their micro-textures before breakage and after breakage (Paper 3). The result is a population of mineral particles stored in a file format compatible to import into process simulation software. The results show that the approach is relevant and can be generalized towards new characterization methods.The theory of image representation, analysis and ore texture simulation is briefly introduced and linked to 1-point, 2-point, and multiple-point methods from spatial statistics. A breakage mechanism is presented as a cellular automaton. Experimental data and examples are taken from a copper-gold deposit with a chalcopyrite flotation circuit, an iron ore deposit with a magnetic separation process.This study is covering a part of a larger research program, PREP (Primary resource efficiency by enhanced prediction).
|
|
| 41. |
- Koch, Pierre-Henri, 1988-, et al.
(författare)
-
Sequential decision-making in mining and processing based on geometallurgical inputs
- 2020
-
Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 149
-
Tidskriftsartikel (refereegranskat)abstract
- Geometallurgy as a multi-disciplinary field has been applied at various levels in different operations. By linking the ore performance in mineral beneficiation processes to the ore block model, it supports estimating the value of a block before it is mined. Efforts in the classification of the ore into geometallurgical classes have led to a better understanding of the entire value chain. While classification provides a convenient tool for forecasting and visualization purposes, it simplifies the actual complexity of an ore body. In mining and process planning, sequential decisions are made to maximize an objective function or equivalently minimize a regret function. Using available information from geology or metallurgical test work, an optimal strategy can be found using tools from the machine learning community.In this study, a framework based on machine learning to maximize the use of such classifications for sequential decision-making is proposed. The concepts of reinforcement learning and bandit algorithms, offer powerful tools to explore and exploit different optimization strategies. In certain cases, theoretical guarantees about the performance of given methods can be obtained by regret bounds.Based on existing models of a porphyry copper deposit and an iron ore deposit, this study presents a methodology and different available algorithms to maximize an objective function that depends on a high number of variables and in the presence of noise or uncertainty in the models. Different numerical experiments provide a basis for discussion and comparison to human decisions. The hypotheses relative to each algorithm are discussed in relation to the mineral processing models.
|
|
| 42. |
- Koch, Pierre-Henri, 1988-, et al.
(författare)
-
Texture-based liberation models for comminution
- 2017
-
Ingår i: Konferens i Mineralteknik 2017. - Luleå. ; , s. 83-96
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The relation between breakage mechanisms and liberation is critical in mineral processing. Recent studies underline the importance of texture in liberation. This study reviews relevant liberation models and proposes a new method for generating particles using image processing algorithms. One new texture simulation method and its relevance for liberation simulation is also introduced.
|
|
| 43. |
|
|
| 44. |
|
|
| 45. |
|
|
| 46. |
|
|
| 47. |
|
|
| 48. |
|
|
| 49. |
|
|
| 50. |
|
|
