Zinc refining research will be carried out at UCT’s Department of Chemical Engineering under the leadership of Prof Jochen Petersen
The International Zinc Association (IZA) Africa Desk has secured “considerable” research funding to investigate the feasibility of new zinc refining processes to meet South Africa’s own demand for refined zinc, while using locally produced ore and concentrates.
Two industrial sponsors – Vedanta South Africa (SA), an IZA member; and Duferco Steel Processing, which galvanises steel in Saldanha Bay – are participating in the project.
Should the research deliver a feasible chemical engineering solution, Saldanha Bay is considered a suitable location for the establishment of a new zinc refinery. Saldanha Bay already has an industrial development zone near a zinc ore export port, as well as a big refined zinc end-user.
“The funding has been secured from within South Africa. The sponsors are very keen to see that we can develop our own capability within South Africa to produce special high-grade refined zinc and, at the same time, support fundamental chemical engineering research, while developing postgraduate research,” reports IZA Africa Desk spokesperson Simon Norton.
“We are very proud of these future-thinking sponsors. Not only are they supporting fundamental research in South Africa, they are also supporting a ‘green’ future for minerals processing,” he adds.
The research will focus on developing and understanding novel refining processes to considerably reduce the external power input compared with traditional pyrometallurgical processes. This will allow for the economically viable production of special high grade refined zinc.
Ore use may be further maximised by producing refined by-products such as silver and rare earth elements.
“The proposed operation will also have a considerably reduced carbon footprint,” adds Norton.
The research work will be carried out at the University of Cape Town (UCT) in its Department of Chemical Engineering under the leadership of Professor Jochen Petersen.
In its proposal, entitled ‘Concept and prefeasibility study of a small-scale zinc refinery in South Africa considering novel processes’, UCT notes that the development of a small-scale, relatively simple and energy-efficient process to recover zinc from polymetallic local concentrates “is a considerable challenge, given the limitations of existing processes”.
In support of this ‘back to the drawing board’ approach to reconsider novel development processes that have never been commercialised to date, IZA Africa Desk launched its campaign for research funding in 2021.
Notably, Vedanta SA will sponsor a desktop study of a variety of zinc processes, while Duferco Steel Processing is funding laboratory-scale research on zinc process chemistry.
The experimental study will carefully explore the in-principle feasibility of a novel flowsheet for refined zinc production and by-product recovery from local ore concentrate materials, with the express emphasis on reduced and/or renewable energy input, as well as reduced carbon and environmental footprints, according to the research team.
Norton says the IZA Africa Desk is working hard to get the use of refined zinc growing again in South Africa.
Recently, South African galvanizers experienced a severe shortage in the refined zinc supply owing to four zinc refineries in Europe closing down. “The situation is compounded by the fact that base metal traders worldwide are selling zinc to Europe at inflated prices, rather than to South Africa at normal market prices,” notes Norton.