日本金属学会誌

J. Japan Inst. Met. Mater, Vol. 81, No. 06 (2017),
pp. 320-326

Selective Nickel Leaching from Nickel and Cobalt Mixed Sulfide Using Sulfuric Acid

Hiroshi Kobayashi 1, Hirofumi Shoji 1, Satoshi Asano 1 and Masaki Imamura 1

1 NIIHAMA RESEARCH LABORATORIES, SUMITOMO METAL MINING CO., LTD.

Abstract:

Sumitomo Metal Mining Co., Ltd. (SMM) has gradually increased the mixed sulfide (MS: mixture of nickel and cobalt sulfides) production from nickel laterite ore as raw material for the SMM's unique Matte Chlorine Leach and Electro-winning (MCLE) process over the past decade. This process has significant cost advantages because it is capable of selectively and effectively leaching nickel from MS; however, chlorine leaching requires expensive corrosion-resistant facilities. A new process that could be operated using lower-cost facilities has therefore been desired. To meet its development needs, this study evaluated a process for nickel-selective leaching from MS, which is similar to the existing process for refining of ZnS. The process uses sulfuric acid, which does not require high-cost facilities. The mechanism of nickel leaching from MS using sulfuric acid was identified. It was shown that nickel-selective leaching using sulfuric acid is difficult because of the formation of elemental sulfur and NiS2 precipitates on the MS surface that interfere with the leaching reaction.

[doi:10.2320/jinstmet.J2016067]


(Received 2016/12/22)

Keywords:

mixed sulfide, sulfuric acid, iron(III) sulfate, nickel selective leaching, NiS2


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