| 1. |
- Abbasalizadeh, Aida, et al.
(författare)
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Highlights of the Salt Extraction Process
- 2013
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Ingår i: JOM. - : Springer Science and Business Media LLC. - 1047-4838 .- 1543-1851. ; 65:11, s. 1552-1558
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Tidskriftsartikel (refereegranskat)abstract
- This article presents the salient features of a new process for the recovery of metal values from secondary sources and waste materials such as slag and flue dusts. It is also feasible in extracting metals such as nickel and cobalt from ores that normally are difficult to enrich and process metallurgically. The salt extraction process is based on extraction of the metals from the raw materials by a molten salt bath consisting of NaCl, LiCl, and KCl corresponding to the eutectic composition with AlCl3 as the chlorinating agent. The process is operated in the temperature range 973 K (700 degrees C) to 1173 K (900 degrees C). The process was shown to be successful in extracting Cr and Fe from electric arc furnace (EAF) slag. Electrolytic copper could be produced from copper concentrate based on chalcopyrite in a single step. Conducting the process in oxygen-free atmosphere, sulfur could be captured in the elemental form. The method proved to be successful in extracting lead from spent cathode ray tubes. In order to prevent the loss of AlCl3 in the vapor form and also chlorine gas emission at the cathode during the electrolysis, liquid aluminum was used. The process was shown to be successful in extracting Nd and Dy from magnetic scrap. The method is a highly promising process route for the recovery of strategic metals. It also has the added advantage of being environmentally friendly.
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| 2. |
- Ananthanarayanan, Durga, et al.
(författare)
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Grain Structure Prediction for Directionally Solidified Superalloy Castings
- 2020
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Ingår i: JOM. - : Springer Nature. - 1047-4838 .- 1543-1851. ; 72:5, s. 1785-1793
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Tidskriftsartikel (refereegranskat)abstract
- A highly parallelized mesoscale solidification model based on a cellular automaton method was coupled with a macroscale process model to predict grain structure during directional solidification. The macroscale thermal model and a nucleation parameter (maximum nucleation density) for René N500 were verified and calibrated using temperature profiles obtained via thermocouples in step-geometry castings and grain structures analyzed by electron backscatter diffraction (EBSD), respectively. The calibrated model was then applied to a laboratory-scale turbine blade to predict its grain structures. The predicted grain sizes agreed with experimental measurements under different casting conditions. The established bulk nucleation parameter based on the simple geometry can be directly transferred to complex geometries. Grain calculations without accurate estimations of nucleation on the chill plate can still provide reasonably good predictions. Overall, a viable path to calibrate model inputs for grain structure models based on simple geometry, where faster iterations can be achieved, is demonstrated.
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| 3. |
- Aune, Ragnhild E., et al.
(författare)
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Thermophysical properties of silicate slags
- 2002
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Ingår i: JOM. - 1047-4838 .- 1543-1851. ; 54:11, s. 62-69
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Tidskriftsartikel (refereegranskat)abstract
- The optimization of metallurgical processes requires reliable data of the slag phase. This paper focuses on three properties that are relevant to heat and mass-transfer calculations-viscosities, thermal diffusivities, and surface tensions of silicate melts. A brief account of the experimental techniques used for the measurements of these properties, with special reference to the work carried out in the Division of Metallurgy, Royal Institute Of Technology, Stockholm, Sweden, are presented, along with the advantages and limitations. As these properties are structure-oriented, the impact of structure on these properties is also presented. The paper is intended as a state-of-the-art review of the subject.
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| 4. |
- Awasthi, Shikha, et al.
(författare)
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Multi-Length Scale Tribology of Electrophoretically Deposited Nickel-Diamond Coatings
- 2017
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Ingår i: JOM. - : Springer Science and Business Media LLC. - 1047-4838 .- 1543-1851. ; 69:2, s. 227-235
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Tidskriftsartikel (refereegranskat)abstract
- Electrophoretically deposited (EPD) nickel and its composite coatings are widely used to enhance the life span of continuous ingot casting molds in the steel, aerospace and automotive industries. This article reports the effect of different concentrations of diamond particles (2.5–10 g/L) on the wear mechanism of EPD Ni. The distribution of diamond particles in the Ni matrix was observed using Voronoi tessellation. Variation in COF was observed by a fretting wear test to be 0.51 ± 0.07 for Ni, which decreases to 0.35 ± 0.03 for the Ni-diamond coatings. The wear volume of the coatings with 7.5 g/L concentration of diamond was observed to be a minimum (0.051 ± 0.02 × 10−3 mm3) compared with other composite coatings. Further, the micro-scratch testing of the coatings also exhibited a reduced COF (0.03–0.12) for 7.5 g/L diamond concentration compared with Ni (0.08–0.13). Higher wear resistance of the diamond-added coatings (optimum 7.5 g/L concentration) is due to the balance between the dispersion strengthening mechanism and the enhancement of the load-bearing capacity due to the incorporation of diamond particles. Thus, these composites can be used for applications in automotive and aerospace industries. © 2016 The Minerals, Metals & Materials Society
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| 5. |
- Bayat, Nazlin, et al.
(författare)
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Surface structure formation in direct chill (DC) casting of al alloys
- 2014
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Ingår i: JOM. - : Springer Science and Business Media LLC. - 1047-4838 .- 1543-1851. ; 66:5, s. 700-710
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to increase the understanding of the surface zone formation during direct chill (DC) casting of aluminum billets produced by the air slip technology. The depth of the shell zone, with compositions deviating from the bulk, is of large importance for the subsequent extrusion productivity and quality of final products. The surface microstructures of 6060 and 6005 aluminum alloys in three different surface appearances - defect free, wavy surface, and spot defects - were studied. The surface microstructures and outer appearance, segregation depth, and phase formation were investigated for the mentioned cases. The results were discussed and explained based on the exudation of liquid metal through the mushy zone and the fact that the exudated liquid is contained within a surface oxide skin. Outward solidification in the surface layer was quantitatively analyzed, and the oxide skin movements explained meniscus line formation. Phases forming at different positions in the segregation zone were analyzed and coupled to a cellular solidification in the exudated layer.
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| 6. |
- Beheshti, Reza, et al.
(författare)
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Black Dross : Processing Salt Removal from Black Dross by Thermal Treatment
- 2014
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Ingår i: JOM. - : Springer Science and Business Media LLC. - 1047-4838 .- 1543-1851. ; 66:11, s. 2243-2252
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Tidskriftsartikel (refereegranskat)abstract
- The salt removal from black dross by thermal treatment has experimentally been studied under different conditions in both a stationary resistance furnace and in a laboratory scale rotary furnace. The experiments were designed based on partial pressure calculations using the Thermo-Calc software (Thermo-Calc Software, Stockholm, Sweden). The salt removal efficiency was evaluated by scanning electron microscope (SEM) energy-dispersive x-ray spectroscopy and x-ray diffraction analyses, and the optimum conditions for treatment established, i.e., temperature, gas flow rate, holding time, rotation rate, and sample size. The overall degree of chloride removal was established to increase as a function of time and temperature, as well as by reduced pressure. Under atmospheric pressure, the highest degree of chloride removal from a 20 g sample was obtained after 10 h at 1523 K resulting in a 98% removal and a final chloride content of 0.3 wt.% in the residue. Under reduced pressure, the chloride concentrate was lowered to 0.2 wt.% after thermal treatment of a 20 g sample at 1473 K for 8 h. In the case of 200 g samples treated in a rotary furnace, the chloride concentrate was 2.5 wt.% after 14 h at 1523 K, representing a removal of 87%. Below 0.3 wt.% chloride content, the material is deemed a nonhazardous waste.
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| 7. |
- Björkman, Bo, et al.
(författare)
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Waste reduction through process optimization and development
- 1996
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Ingår i: JOM. - 1047-4838 .- 1543-1851. ; 48:3, s. 45-49
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Tidskriftsartikel (refereegranskat)abstract
- In this article, the possibilities of optimizing metallurgical processes based on minimization for waste reduction and application requirements for the reuse of waste products are discussed together with the possibilities of treating existing waste in direct connection with the process involved. Some results from ongoing projects on controlled dust generation and an outline of an ongoing research program are also described.
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| 8. |
- Buffington, Jack, et al.
(författare)
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Defining a Closed-Loop US Aluminum Can Supply Chain Through Technical Design and Supply Chain Innovation
- 2013
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Ingår i: JOM. - : Springer Science and Business Media LLC. - 1047-4838 .- 1543-1851. ; 65:8, s. 941-950
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study is to conduct a supply chain material flow analysis (MFA) for the U.S. aluminum can market, consistent with studies conducted for the overall worldwide aluminum industry. A technical definition of the use of alloys 5182 and 3104 is conducted by metallurgists for use in the "aluminum can" MFA. Four propositions are created: technical, economic, and supply chain factors are as important to secondary aluminum recycling in an aluminum can as higher recycling rates (P-1); the development of a unialloy aluminum can will increase reuse rates, but recycling rates must increase for this to happen (P-2); a closed-loop aluminum can supply chain is not able to be fully realized in today's environment but is very useful for understanding improvement through both supply and demand (P-3); and UBC supply can improve through a "voluntary deposit-refund system" approach (P-4).
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| 9. |
- Buffington, Jack
(författare)
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The Beverage Can in the United States : Achieving a 100% Recycled Aluminum Can through Supply Chain Innovation
- 2012
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Ingår i: JOM. - : Springer Science and Business Media LLC. - 1047-4838 .- 1543-1851. ; 64:8, s. 923-932
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this research is to analyze why recycled content is low (33-50%) in the aluminum can in the United States when it is technically possible to have a product that is made from 100% recycled material. A comprehensive literature review is conducted, followed by identification of five propositions determined with respect to the research problem. With respect to aluminum can recycling (and its research), there is a greater focus on the role of the consumer than the producer in the aluminum can supply chain system, which may impact on the role of innovation in addressing the problem. The upstream primary aluminum supply chain is vertically integrated and efficient within itself, but not integrated with the downstream secondary aluminum can market. Given the importance of the secondary aluminum market in the United States, there are significant recycling/efficiency/sustainability opportunities to address. As opposed to a dominant focus on consumers and their recycling habits, this study focuses on the aggregate aluminum can supply chain to apply innovation to the solution.
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| 10. |
- Cai, Xiaoping, et al.
(författare)
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Fabrication of Highly Porous CuAl Intermetallic by Thermal Explosion Using NaCl Space Holder
- 2018
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Ingår i: JOM. - : The Minerals, Metals, and Materials Society. - 1047-4838 .- 1543-1851. ; 70:10, s. 2173-2178
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Tidskriftsartikel (refereegranskat)abstract
- A high-porosity CuAl-based intermetallic compound with composition Cu-50 at.% Al has been successfully prepared by thermal explosion (TE) using NaCl as space holder. The results showed that the NaCl particles were completely removed from the green compact by water leaching. The temperature of the specimen during the TE and the evolution of the porous microstructure were investigated. The TE was ignited at 560°C, and the specimen temperature increased to 775°C in 3 s, resulting in formation of intermetallic CuAl and CuAl2 phases in the final product. A porous CuAl-based intermetallic compound with up to 62 vol.% open porosity was produced when adding 60 vol.% NaCl. The compound exhibited a bimodal pore size structure, including large pores (200 μm to 300 μm) that replicated the NaCl particles and small pores (5 μm to 10 μm) interspersed in the pore walls. Moreover, the large pores were interconnected by channels and formed an open CuAl-based intermetallic cellular structure, having great potential for use in heat exchange and filtration applications.
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