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Publications (4 of 4) Show all publications
Awe, S. A., Seifeddine, S., Jarfors, A. E. .., Lee, Y. C. & Dahle, A. (2017). Development of new Al-Cu-Si alloys for high temperature performance. Advanced Materials Letters, 8(6), 695-701
Open this publication in new window or tab >>Development of new Al-Cu-Si alloys for high temperature performance
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2017 (English)In: Advanced Materials Letters, ISSN 0976-3961, E-ISSN 0976-397X, Vol. 8, no 6, p. 695-701Article in journal (Refereed) Published
Abstract [en]

In a quest to develop new light metal alloys that can perform excellently at elevated-temperatures (from 300°C to 400°C), a ternary eutectic Al-Cu-Si alloy was exploited to gain a deeper understanding of the alloy system and its suitability for high temperature applications. The alloys studied, with chemical composition of Al-27%Cu-5%Si (by weight percent) with Ni addition in the range of 0 to 1.5%wt, were cast in a rapid solidification casting technique. The solidification characteristics of the alloy was studied using the Thermo-Calc software. Microstructures were characterized in a scanning electron microscope coupled with energy dispersive spectrometry (SEM-EDS). Finally, the elevated-temperatures tensile properties of the alloys were investigated. Comparing the microstructures and mechanical properties of these Al-Cu-Si(-Ni) alloys with conventional Al-Si alloy A319, the refined microstructure with dispersed Ni intermetallic particles formed in the as-cast Al-Cu-Si(-Ni) alloys deliver improved elevated temperature properties. In particular, the yield strength and ultimate tensile strength of the new alloy with 1.5% Ni at 400?C were observed to be 220% and 309% higher, respectively, than for conventional A319 alloy.

Place, publisher, year, edition, pages
VBRI Press, 2017
Keywords
Eutectic composite structure, casting, solidification, elevated-temperature performance, thermo-calc, tensile properties
National Category
Metallurgy and Metallic Materials Other Materials Engineering
Identifiers
urn:nbn:se:hj:diva-34093 (URN)10.5185/amlett (DOI)
Available from: 2016-11-28 Created: 2016-11-28 Last updated: 2020-01-29
Wikedzi, A. & Awe, S. A. (2017). Selective Extraction of Antimony and Arsenic from Decopperization Slime Using Experimental Design. Journal of sustainable metallurgy, 3(2), 362-374
Open this publication in new window or tab >>Selective Extraction of Antimony and Arsenic from Decopperization Slime Using Experimental Design
2017 (English)In: Journal of sustainable metallurgy, ISSN 2199-3823, Vol. 3, no 2, p. 362-374Article in journal (Refereed) Published
Abstract [en]

The aim of the present study is to selectively extract antimony and arsenic from decopperization slime through alkaline sulfide hydrometallurgy with a view to recycle the obtained solid residue within the copper smelter, and also regenerate the sulfide lixiviant during the process. Rechtschaffner experimental design was used to evaluate the joint influence of several experimental parameters such as leaching temperature, Na2S concentration, solid concentration, and reaction time on the extraction of antimony and arsenic from the material. The most active parameters influencing the extraction of the metals are solid concentration and reaction period. In addition, the results show that solid concentration interacted strongly with the leaching time and slightly with reaction temperature, which is an indication that solid concentration is the predominant influencing factor in removing antimony and arsenic from the material. It is also indicated from the results that about 95% Sb and 89% As were extracted when 50 g/L of the decopperization slime was dissolved in alkaline sulfide lixiviant containing 200 g/ L Na2S ? 20 g/L NaOH at 60 C for 24 h. Moreover, analysis of the leach residue reveals that copper sulfide and lead sulfide remain as the main constituents of the residue. The bismuth-containing mineral phase was not observed in the residue because of its low concentration, and also the Sb/As-bearing mineral phases were not detected due to the selectivity of the leaching reagent to the metals. Based on the experimental results from this investigation, a process flowsheet for the alkaline sulfide treatment of a decopperization slime was proposed with a view to eliminating its antimony and arsenic contents in a sustainable manner.

Place, publisher, year, edition, pages
Springer, 2017
Keywords
Decopperization slime, Antimony, Arsenic, Alkaline sulfide, Rechtschaffner design, Response contour plot
National Category
Metallurgy and Metallic Materials Other Materials Engineering
Identifiers
urn:nbn:se:hj:diva-34578 (URN)10.1007/s40831-016-0101-5 (DOI)000400824500016 ()
Available from: 2016-12-27 Created: 2016-12-27 Last updated: 2020-01-29Bibliographically approved
Awe, S. A., Seifeddine, S., Jarfors, A. E. W. & Dahle, A. (2016). Development of cast Al-Cu-Si ternary eutectic alloys for high temperature applications. In: Ashutosh Tiwari (Ed.), Proceedings and Abstracts Book of European Advanced Materials Congress, At Stockholm, Sweden: . Paper presented at European Advanced Materials Congress, 23-25 August 2016, Stockholm, Sweden. Linköping: VBRI Press
Open this publication in new window or tab >>Development of cast Al-Cu-Si ternary eutectic alloys for high temperature applications
2016 (English)In: Proceedings and Abstracts Book of European Advanced Materials Congress, At Stockholm, Sweden / [ed] Ashutosh Tiwari, Linköping: VBRI Press , 2016Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Linköping: VBRI Press, 2016
Keywords
Eutectic ultrafine structure; Aluminium alloy; Solidification; Elevated temperature performance; Thermodynamics
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-31611 (URN)10.5185/eamc2016 (DOI)978-91-88252-02-9 (ISBN)
External cooperation:
Conference
European Advanced Materials Congress, 23-25 August 2016, Stockholm, Sweden
Available from: 2016-09-01 Created: 2016-09-01 Last updated: 2020-01-29Bibliographically approved
Wikedzi, A., Sandström, Å. & Awe, S. A. (2016). Recovery of antimony compounds from alkaline sulphide leachates. International Journal of Mineral Processing, 152, 26-35
Open this publication in new window or tab >>Recovery of antimony compounds from alkaline sulphide leachates
2016 (English)In: International Journal of Mineral Processing, ISSN 0301-7516, E-ISSN 1879-3525, Vol. 152, p. 26-35Article in journal (Refereed) Published
Abstract [en]

In copper metallurgy, antimony impurities usually form alloys and compounds with the transition metals to make up the basic building blocks of a speiss phase. This speiss phase is generally rich in copper and precious metals, which are desirable to recycle and recover at the smelter. The presence of this impurity unfortunately creates a build-up of this metal in the copper circuit, leading to problems during copper refining processes. Therefore, a removal or reduction of the antimony impurity to an acceptable level is a necessary step before the speiss can be recycled at the smelter for the recovery of its valuable metals. A lead silicate slag that was obtained after smelting a copper speiss admixed with silica, soda and lead oxide, was leached in alkaline sulphide solution to selectively dissolve its antimony content. Furthermore, the pregnant sulphide leachate was purified by precipitation and crystallization techniques to recover antimony as sodium thioantimonate and sodium hydroxyl antimonate using synthetic Na2S-NaOH-Sb2S3 solutions. The leaching results indicate that the highest amount of antimony and arsenic extracted from the material after 24 h at 100 °C and reagent concentration of 30 g/L NaOH + 30 g/L S2− was 83% and 90%, respectively. In the precipitation process, the addition of hydrogen peroxide to the alkaline sulphide leachate prompts the precipitation of antimony as NaSb(OH)6. The result also implies that b100% of stoichiometric hydrogen peroxide is required to completely oxidize the total amounts of both Sb3+ and S2− in the solution and to quantitatively precipitate N90% of the antimony in solution. The influence of catalytic agents and temperature on the process was not clearly reflected in this investigation due to the exothermic reaction with hydrogen peroxide. Moreover, the addition of elemental sulphur to the sulphide leachate also in- fluences the precipitation of antimony as sodium thioantimonate.

Keywords
Alkaline sulphide leaching, Catalytic agents, Crystallization, Lead silicate slag, Purification, Sodium hydroxyl antimonate, Sodium thioantimonate
National Category
Metallurgy and Metallic Materials Other Materials Engineering
Identifiers
urn:nbn:se:hj:diva-34576 (URN)10.1016/j.minpro.2016.05.006 (DOI)000378954200004 ()2-s2.0-84969780233 (Scopus ID)JTHMaterialIS (Local ID)JTHMaterialIS (Archive number)JTHMaterialIS (OAI)
Available from: 2016-12-27 Created: 2016-12-27 Last updated: 2020-01-29Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5874-5473

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