氯气氧化分解草酸钴沉淀母液中的草酸

Oxidation of oxalic acid by chlorine in mother-liquor originated from precipitation of cobalt oxalate

为有效去除草酸沉钴母液中残留的大量草酸,采用氯气作为氧化剂探索氧化分解母液中草酸的可行性。考察反应温度、反应时间、氯气用量、搅拌速度和钴离子浓度等因素对氧化效果的影响。确定了优化工艺条件:反应温度50℃,搅拌速度700 r/min,次氯酸钙150 g,6 mol/L盐酸550 mL,反应时间3 h。在此条件下,草酸的氧化率可达97.9%,母液中残留的草酸质量浓度仅为0.42 g/L,处理后的母液可直接返回含钴物料的浸出,实现了工艺流程的闭路循环。

In order to remove the oxalic acid left in the mother-liquor originated from the precipitation of cobalt by oxalic acid,a novel method of using chlorine as the oxidant to decompose the oxalic acid was proposed.The main factors affecting the oxidation rate such as the solution temperature,reaction time,quantity of chlorine,stirring speed and Co2＋ concentration were investigated.The optimal conditions are as follows： 700 r/min of stirring speed,150 g calcium hypochlorite,550 mL of hydrochloric acid with concentration of 6 mol/L and 5 h of reaction time at 70 ℃.Under these conditions,the oxidation rate of oxalic acid is 97.9% and the concentration of residual oxalic acid in mother liquor is only 0.42 g/L.The treated mother liquor can be returned directly for leaching cobalt.There is a closed circulation in the whole process.