刚果(金)某铜钴矿含钴萃余液制备粗制钴盐的工艺及试验研究

Experimental Research on Processing Technique for Preparation of Crude Cobalt Salt from Cobalt-Containing Raffinate of Copper-Cobalt Ore in DRC

针对刚果(金)某铜钴氧化矿含钴萃余液,采用生石灰与氧化镁为沉淀剂、焦亚硫酸钠与压缩空气为氧化剂,经除杂、一段沉钴、二段沉钴等工序,制备了粗制氢氧化钴销售产品。结果表明,适宜的除杂工艺条件为:生石灰浓度15%、反应时间5 h、反应pH=4.5、电位420 mV,此时除铁率达99.5%;一段沉钴适宜工艺条件为:反应pH=8.0、反应时间6 h、氧化镁加入量(t_(MgO)/t_(Co))1.0,一段沉钴制备的氢氧化钴含钴45.6%;二段沉钴优化工艺条件为:反应时间3 h、反应pH=9.0,二段沉钴渣含钴34.2%;将二段沉钴渣全部返回一段沉钴工序作反应晶种,最终钴盐产品钴含量39.65%,完全满足产品销售要求。

With quicklime and magnesium oxide as a precipitating agent,sodium metabisulfite and compressed air as an oxidant,the cobalt-containing raffinate from a copper-cobalt oxide ore in DRC was taken firstly for impurity removal,and then subjected to two stages of cobalt precipitation,and finally a kind of crude cobalt salt was prepared.It is found that with appropriate impurity removal conditions including quicklime concentration of 15%,reaction time of 5 h,pH of 4.5 and potential of 420 mV,the iron removal rate can reach 99.5%.After that,with reaction pH of 8.0,reaction time of 6 h and t_(MgO)/t_(Co) ratio of 1.0 for the first stage of cobalt precipitation,the prepared cobalt hydroxide contains 45.6%of cobalt;and then with reaction time of 3 h,pH of 9.0 for the second stage of cobalt precipitation,the obtained precipitated residue contains 34.2%of cobalt.The precipitated residue from two stages is then all returned to the first stage of cobalt precipitation process as seed crystals in reaction,resulting in the cobalt content of 39.65%in the final cobalt salt product,meeting the requirement for sale.