Wise process routes for varying feedstock in base metal extraction

• In Sweden, there are several large but low-grade ore deposits that have not been extracted so far. The main reason is presence of impurities such as arsenic and antimony that increase the overall cost of the process and make the extraction uneconomical. In-depth experimental studies, plant data and theoretical modelling and innovations are needed to develop new techniques for an efficient use of the resources. Besides, recycling of metals from end of life scrap and metal containing waste, e.g. waste electric and electronic equipment (WEEE), is an important part of a metal production plant. Most of these secondary raw materials contain mixtures of different metals together with various plastics and ceramics that may adversely affect products and by-products of the metallurgical opera-tion. Therefore, a thorough study on how to control possible changes of properties is required. The aim of the research is to develop an optimum combination of hydro- and pyro- metallurgical path-ways to bleed out impurities from the metal extraction chain and/or convert them into valuable by-products. The first part of the current paper focuses on impurity removal from a complex copper concentrate as an upgrading stage. It is shown that by selective dissolution of tetrahedrite in alkaline sulphide solution, antimony and arsenic would be eliminated and the concentrate can be treated in pyro-metallurgical processes. In the second part of the paper, influences of one of the most common and significant compounds that is included in most of the secondary raw materials, alumina Al2O3, on properties of a copper production slag are explained. Results show that increased alumina content of the slag will cause formation of a new phase and rises the liquidus temperature, while its leaching properties are not adversely affected.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

Process Metallurgy

Processmetallurgi

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