有機王水を用いたニッケル・コバルト混合硫化物の浸出と二相分離による回収

抄録

The reactivity of Mixed sulfide (MS: mixture of nickel and cobalt sulfides) in the conventional media remains insufficient and may be further improved. The authors have developed a novel leaching method using organic aqua regia, i.e. dimethyl sulfoxide (DMSO) solutions of copper chloride (CuCl₂). In this work, the organic aqua regia was applied for the leaching of MS. Then, the recovery of Ni from the leachate was conducted by a biphasic extraction, during which commercial extractants of PC-88A were used. It was found that the extraction of Ni and Co at a given time was faster than that of conventional media, e.g. 94％ in 1 h at 393 K. One of the advantages of DMSO as a solvent is its high boiling point, which allows a high operating temperature at ambient pressure, leading to high extraction rate. The results of the biphasic extraction show that approximately 80％ of Cu remains in the leachate whereas 70％ of Ni goes to PC-88A. The leaching by organic aqua regia followed by the biphasic extraction could be a novel and attractive method to recovery Ni from MS.

Fig. 4　Effects of temperature and time on leaching fractions, L.