| 1. |
- Chen, Yuran, et al.
(författare)
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Resource utilization strategies for spent pot lining: A review of the current state
- 2022
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Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 300
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Forskningsöversikt (refereegranskat)abstract
- During a long-term operation of the aluminum electrolysis cell, the molten salts continuously infiltrate and corrode the pot lining, resulting in a huge amount of hazardous waste after the overhaul. The first cut of spent pot linings (SPL) contains several carbon-rich materials with potential economic value and hazardous matters such as soluble fluorite and cyanide. The continuous accumulation and disposal of SPL in depots or landfills have created a severe challenge to the aluminum industry. Nowadays, the technologies of harmless disposal and resource utilization of SPL have been paid more attention. This work has explored and presented the properties of SPL (including chemical, physical, and thermodynamic properties, etc.) and methods for its detoxification and purification. In this regard, the resource utilization strategies of SPL are systematically sorted out from three aspects: traditional, co-processing, and high-value technologies. In the end, the current challenges and future perspectives for the environmental recycling of SPL have been analyzed and summarized.
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| 2. |
- Asghari, M., et al.
(författare)
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Recovery of coal particles from a tailing dam for environmental protection and economical beneficiations
- 2018
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Ingår i: International Journal of Coal Science & Technology. - : Springer. - 2095-8293 .- 2198-7823.
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Tidskriftsartikel (refereegranskat)abstract
- Considerable amounts of coal particles are accumulated in the tailing dams of washing plants which can make serious environmental problems. Recovery of these particles from tailings has economically and environmentally several advantages. Maintaining natural resources and reducing discharges to the dams are the most important ones. This study was examined the possibility to recover coal particles from a tailing dam with 56.29% ash content by using series of processing techniques. For this purpose, gravity separation (jig, shaking table and spiral) and flotation tests were conducted to upgrade products. Based the optimum value of these processing methods, a flowsheet was designed to increase the rate of recovery for a wide range of coal particles. Results indicated that the designed circuit can recover over 90% of value coal particles and reduce ash content of product to less than 14%. These results can potentially be used for designing an industrial operation as a recycling plant and an appropriate instance for other areas to reduce the environmental issues of coal tailing dams.
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| 3. |
- Asimi Neisiani, Ali, et al.
(författare)
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Biodegradable acids for pyrite depression and green flotation separation–an overview
- 2024
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Ingår i: Critical reviews in biotechnology. - : Taylor & Francis. - 0738-8551 .- 1549-7801. ; 44:6, s. 1226-1240
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Forskningsöversikt (refereegranskat)abstract
- Exponential increasing demands for base metals have made meaningful processing of their quite low-grade (>1%) resources. Froth flotation is the most important physicochemical pretreatment technique for processing low-grade sulfide ores. In other words, flotation separation can effectively upgrade finely liberated base metal sulfides based on their surface properties. Various sulfide surface characters can be modified by flotation surfactants (collectors, activators, depressants, pH regulators, frothers, etc.). However, these reagents are mostly toxic. Therefore, using biodegradable flotation reagents would be essential for a green transition of ore treatment plants, while flotation circuits deal with massive volumes of water and materials. Pyrite, the most abundant sulfide mineral, is frequently associated with valuable minerals as a troublesome gangue. It causes severe technical and environmental difficulties. Thus, pyrite should be removed early in the beneficiation process to minimize its problematic issues. Recently, conventional inorganic pyrite depressants (such as cyanide, lime, and sulfur-oxy compounds) have been successfully assisted or even replaced with eco-friendly and green reagents (including polysaccharide-based substances and biodegradable acids). Yet, no comprehensive review is specified on the biodegradable acid depression reagents (such as tannic, lactic, humic acids, etc.) for pyrite removal through flotation separation. This study has comprehensively reviewed the previously conducted investigations in this area and provides suggestions for future assessments and developments. This robust review has systematically explored depression performance, various adsorption mechanisms, and aspects of these reagents on pyrite surfaces. Furthermore, factors affecting their efficiency were analyzed, and gaps within each area were highlighted.
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| 4. |
- Asimi Neisiani, A., et al.
(författare)
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Biodegradable hematite depressants for green flotation separation – An overview
- 2023
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Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 199
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Forskningsöversikt (refereegranskat)abstract
- Due to environmental issues and the restrictions imposed on mineral flotation separation, the use of biodegradable and environmentally friendly reagents has gained widespread international attention. So far, several investigations have been conducted regarding the eco-friendly flotation separation of iron oxide ores for moving toward sustainable development and cleaner production. Yet, no critical review is specified on the green and eco-friendly depression reagents through their reverse flotation beneficiation. Therefore, this study will comprehensively discuss the previously conducted works in this area and provides suggestions for future assessments and developments. This robust study explored various adsorption aspects of natural-based depressants (polysaccharide-, polyphenolic-, and lignosulfonate-based) on iron oxide minerals (mainly hematite) to create a possible universal trend for each biodegradable depressant derivative. The laboratory and industrial experiments indicated that these depressants (except lignosulfonate-based) could selectively depress hematite at alkaline pHs and enhance its reverse flotation separation from their gangue phases (especially silicates as the main gangue phases). Although these eco-friendly depressants showed promising metallurgical results, several gaps still need to be addressed, notably in surface analyses and their adsorption mechanisms.
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| 5. |
- Bu, Xiangning, et al.
(författare)
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Exploring the Relationships between Gas Dispersion Parameters and Differential Pressure Fluctuations in a Column Flotation
- 2021
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Ingår i: ACS Omega. - : Elsevier. - 2470-1343. ; 6:34, s. 21900-21908
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Tidskriftsartikel (refereegranskat)abstract
- Flotation separation, which is the most important mineral beneficiation technique, is dependent on gas dispersion (hydrodynamic conditions). Thus, many investigations have focused on the precise determination of hydrodynamic conditions such as Reynolds number of the bubbles, bubble velocity, and bubble diameter. However, few studies have examined their relationships with pressure fluctuations in a column flotation. This study introduced the differential pressure fluctuations as an actual variable that could be considered to determine the collection zone’s hydrodynamic conditions in a cyclonic microbubble flotation column. In general, the outcomes indicated that superficial gas velocity had the most substantial relationship with the differential pressure fluctuations among other flotation factors (such as pump speed, superficial gas velocity, superficial water velocity, and frother dosage). Furthermore, a high coefficient of determination (R2 > 0.77) for the equation generated to assess the relationships demonstrated that differential pressure fluctuations could be used as a promising tool to determine the hydrodynamic parameters’ characteristics in the flotation columns.
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| 6. |
- Bu, Xiangning, et al.
(författare)
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Modelling of coal flotation responses based on operational conditions by random forest
- 2021
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Ingår i: International Journal of Oil, Gas and Coal Technology. - : InderScience Publishers. - 1753-3309 .- 1753-3317. ; 27:4, s. 457-468
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Tidskriftsartikel (refereegranskat)abstract
- Coal consumption is one of the critical factors in the economy of China. Flotation separation of coal from its inorganic part (ash) can reduce environmental problems of coal consumption and improve its combustion. This investigation used random forest (RF) as an advanced machine learning method to rank flotation operations by variable importance measurement and predict flotation responses based on operational parameters. Fifty flotation experiments were designed, and performed based on various flotation conditions and by different variables (collector dosage, frother dosage, air flowrate, pulp density, and impeller speed). Statistical assessments indicated that there is a significant negative correlation between yield and ash content. Experiments indicated that in the optimum conditions, yield and ash content would be 80 and 9%, respectively. Variable importance measurement by RF showed that frother has the highest effectiveness on yield. Outcomes of modelling released that RF can accurately be used for ranking flotation parameters, and generating models within complex systems in mineral processing.
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| 7. |
- Chehreh Chelgani, Saeed, et al.
(författare)
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CatBoost-SHAP for modeling industrial operational flotation variables – A “conscious lab” approach
- 2024
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Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 213
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Tidskriftsartikel (refereegranskat)abstract
- Flotation separation is the most important upgrading critical raw material technique. Measuring interactions within flotation variables and modeling their metallurgical responses (grade and recovery) is quite challenging on the industrial scale. These challenges are because flotation separation includes several sub-micron processes, and their monitoring won't be possible for the processing plants. Since many flotation plants are still manually operating and maintaining, understanding interactions within operational variables and their effect on the metallurgical responses would be crucial. As a unique approach, this study used the “Conscious Lab” concept for modeling flotation responses of an industrial copper upgrading plant when Potassium Amyl Xanthate substituted the secondary collector (Sodium Ethyl Xanthate) in the process. The main aim is to understand and compare interactions before and after the collector substitution. For the first time, the conscious lab was constructed based on the most advanced explainable artificial intelligence model, Shapley Additive Explanations, and Catboost. Catboost- Shapley Additive Explanations could accurately model flotation responses (less than 2% error between actual and predicted values) and illustrate variations of complex interactions through the substitution. Through a comparative study, Catboost could generate more precise outcomes than other known artificial intelligence models (Random Forest, Support Vector Regression, Extreme Gradient Boosting, and Convolutional Neural Network). In general, substituting Sodium Ethyl Xanthate by Potassium Amyl Xanthate reduced process predictability, although Potassium Amyl Xanthate could slightly increase the copper recovery.
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| 8. |
- Chelgani, Saeed Chehreh, et al.
(författare)
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A Review of Graphite Beneficiation Techniques
- 2016
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Ingår i: Mineral Processing and Extractive Metallurgy Review. - : Taylor & Francis. - 0882-7508 .- 1547-7401. ; 37:1, s. 58-68
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Tidskriftsartikel (refereegranskat)abstract
- Graphite as the most common polymorph of naturally occurring crystalline carbon is required for many different applications such as batteries, refractories, electrical products, and pencils. Graphite resources are currently being subjected to intensive exploration to help meet rapidly growing global demand – and graphite has made it onto the list of critical raw materials as issued by the European Union. Graphite ore is mostly beneficiated using flotation separation techniques. The increasing demand for high-grade graphite products with up to 99.99% carbon has resulted in the development of various approaches to remove impurities even to parts per million range. This paper considers separation and purification techniques that are currently employed for graphite mineral beneficiation, and identifies areas in need of further research.
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| 9. |
- Chelgani, Saeed Chehreh, et al.
(författare)
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Estimating REY content of eastern Kentucky coal samples based on their associated ash elements
- 2018
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Ingår i: Journal of Rare Earths. - : Elsevier. - 1002-0721 .- 2509-4963. ; 36:11, s. 1234-1238
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Tidskriftsartikel (refereegranskat)abstract
- Coal and coal combustion byproducts can be considered as an alternative source of rare earth elements and yttrium (REY). The study of relationships between REY and other main coal properties could have several advantages such as estimating REY content of coal particles and designing beneficial extraction method. In this investigation, inter-correlations between REY content with coal parameters (proximate and ash elements) for a wide range of eastern Kentucky coal samples (708 records) were explored. Results demonstrate that zircon and monazite are the main source of heavy and light rare earth elements (HREE and LREE), respectively. Zr has the highest correlation with Y and Th has the strength relationship with Ce and La. In general, LREE have higher interaction with coal ash content in comparison with HREE. Results indicated that REY can be estimated quite satisfactorily by using their associated elements in coal ash.
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| 10. |
- Chelgani, Saeed Chehreh, et al.
(författare)
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Estimation of free-swelling index based on coal analysis using multivariable regression and artificial neural network
- 2011
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Ingår i: Fuel Processing Technology. - : Elsevier. - 0378-3820. ; 92:3, s. 349-355
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Tidskriftsartikel (refereegranskat)abstract
- The effects of proximate, ultimate and elemental analysis for a wide range of American coal samples on Free-swelling Index (FSI) have been investigated by multivariable regression and artificial neural network methods (ANN). The stepwise least square mathematical method shows that variables of ultimate analysis are better predictors than those from proximate analysis. The non linear multivariable regression, correlation coefficients (R2) from ultimate analysis inputs was 0.71, and for proximate analysis input variables was 0.49. With the same input sets, feed-forward artificial neural network (FANN) procedures improved accuracy of predicted FSI with R2 = 0.89, and 0.94 for proximate and ultimate analyses, respectively. The ANN based prediction method, as a first report, shows FSI is a predictable variable, and ANN can be further employed as a reliable and accurate method in the free-swelling index prediction.
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