The Jarogain Process for Metals Recovery from Jarosite and Electric Arc Furnace Dust: Process Design and Economics

The Jarogain process provides a unique hydrometallurgical approach for treating zinc-containing side-streams and residues, in particular jarosite, gothite and electric arc furnace dust. The process is based on a sequence of steps, in which the feedstock is first leached in a reducing environment, and its metal contents are subsequently separated as hydroxide and sulfide precipitates. Finally, the remaining iron is crystallised from the solution. Key products of the Jarogain process are: i) lead concentrate, also containing silver and gold, ii) mixed indium, gallium and germanium concentrate, iii) zinc concentrate, iv) iron concentrate, and v) sulfuric acid. Gypsum silicate and a separate arsenic precipitate remain as solid residues. A purified aqueous effluent is purged from the process. A plant processing 400 000 t of jarosite and 50 000 t of EAF-dust annually would require an investment of 390 million. The battery limit cost of the actual Jarogain process is 200 million. Almost 50 % of the overall costs are generated by the auxiliary units such as the sulfuric acid plant and power boiler required for the operation. The economic feasibility of the Jarogain process was assessed on the basis of the discounted cash flow analysis. The levelized cost of production for the metal concentrates was estimated to be 80% of the pure metal prices. The greatest uncertainties with regard to the economic feasibility relate to the investment costs and the values of lead and zinc concentrates. According to the laboratory scale proof-of-concept results obtained, the Jarogain process remains an interesting alternative for processing residues and side-streams containing zinc. Further studies should focus on continuous piloting of the proposed concept in order to support a more rigorous feasibility study in terms of process economy.