还原浸出—除杂—活性氧化镁沉淀工艺从刚果金某氧化铜钴矿中回收钴

采用还原浸出—除杂—活性氧化镁沉钴工艺从刚果（金）某氧化铜钴矿中回收钴，考察了还原剂焦亚硫酸钠加入方式、用量、浸出反应时间，除杂反应时间，沉钴活性氧化镁加入方式、用量及沉钴反应时间的影响。结果表明，当磨矿细度74μm含量70%、矿浆质量浓度33%、加入硫酸控制终点pH值在1.5~1.8、硫酸加入30 min后，加入焦亚硫酸钠、焦亚硫酸钠用量8 kg/t矿、搅拌浸出5 h时，钴浸出率可达90.38%；浸出液萃取铜后的萃余液采用石灰石+石灰配合除杂，常温下搅拌反应6 h，控制终点pH在5.8左右，石灰加入3 h后溶液中铜可降低至0.04 g/L，铜沉淀率90.51%，铁沉淀率99.23%，钴沉淀率7.39%，沉淀渣返回浸出工序再回收铜钴；除杂后的溶液采用活性氧化镁沉钴，活性氧化镁乳化5 min之内加入，当MgO用量与Co质量比为1.03、沉钴时间5 h时，钴沉淀率达90.13%，所得氢氧化钴沉淀符合行业二级品标准要求。 

Study on Recovering Cobalt from the Congo Cobalt-containing Copper Oxide Ore by Reduction Leaching -Impurities Removal -Cobalt Precipitation with Active Magnesium Oxide

In order to recover cobalt from the Congo cobalt-containing copper oxide ore, the process of reduction leaching-impurity removal-cobalt precipitation with active magnesium oxide has developed. The effects of adding methods and dosages of sodium metabisulfite, leaching reaction time, impurity removal reaction time, the adding methods and dosages of active magnesium oxide, precipitation reaction time were studied. The results showed that under conditions of particle size 74 μm 70%, pulp density 33%, pH 1.5~1.8, sodium metabisulfite 8 kg/t ore, added 30 minutes after sulfuric acid, reaction time 5 h, the cobalt leaching rate is 90.38%; After copper SX, limestone and lime were used to remove impurities from raffinate, 6 hours at room temperature, and the endpoint pH was controlled at about 5.8, the copper precipitation rate was 90.51%. The iron precipitation rate was 99.23%, the cobalt precipitation rate was 7.39%.The precipitated residue was returned to the leaching process to recover copper and cobalt; The solution after impurity removal were sent to precipitate cobalt by active magnesium oxide. The active magnesium oxide was added within 5 minutes of emulsification. Under conditions of the mass ratio of MgO and Co 1.03, reaction time 5 h, the cobalt precipitation rate was 90.13%.The cobalt hydroxide precipitation meets the requirements of the industry's secondary product standards.