镍钼矿提钼渣中镍的浸出工艺

Leaching process of nickel from leaching residue of metalliferous black shales

在硫酸溶液中,使用常压氧化浸出法处理镍钼矿提钼渣以回收有价金属镍。考察搅拌速度、液固比、硫酸用量、氧化剂用量以及浸出时间对镍浸出过程的影响。试验结果表明:搅拌速度与液固比对浸出过程影响不明显;在未加入氧化剂时,主要发生镍氢氧化物简单的酸溶反应,而添加氧化剂后硫化物也被氧化浸出;此外,镍浸出率随浸出时间、温度及硫酸用量的增加而增大。最佳工艺条件如下:搅拌速度为500 r/min,液固比为4:1,氧化剂加入量为矿量的0.2倍,浸出温度为90℃,硫酸浓度为0.4 mol/L,浸出时间为8 h,镍浸出率可达95%左右。

Molybdenum can be selectively extracted from metalliferous black shales in the hydrometallurgical process using air as oxidant.By the process,nickel keeps in residue.The residue is treated by oxidative leaching in sulfuric acid solution for extraction of nickel.The effects of experimental conditions were investigated,such as agitation speed,concentration of sulphuric acid,liquid-solid ratio,the amount of oxidant,temperature and leaching time.The results show that agitation speed and liquid-solid ratio affect nickel recovery little,while long enough leaching time,high enough temperature and concentration of sulphuric acid are necessary.Even if oxidant reagent is not added to leaching solution,most part of nickel existing as hydroxide can be leached through simple acid-dissolution.Other parts that exist as sulfide can only be leached under oxidative condition.The optimum parameters are as follows： agitation speed is 500 r/min,concentration of sulphuric acid is 0.4 mol/L,liquid-solid ratio is 4？1,the amount of oxidant is 0.2 times of the ore,temperature is 90 ℃ and leaching tim e is 8 h.Under the above experimental conditions,the recovery of nickel can reach about 95%.