酸浸出法回收冶金污泥中的有价金属

Recycling of valuable metals from metallurgical sludge by acidic leaching process

采用二次酸浸出的方法回收镍钴湿法冶金工业污泥中的有价金属。先采用水和硫酸作为浸出剂浸出Mg和Na,最佳工艺条件为浸出液的pH 7.5、浸出时间5 min、浸出剂体积与干污泥质量的比(ω)为10 mL/g。再采用硫酸作为浸出剂、焦亚硫酸钠作为还原剂进行二次酸浸,在硫酸与污泥质量比为1.3、焦亚硫酸钠与污泥质量比为0.3、ω为5 mL/g、浸出温度85℃、浸出时间20 min的最佳工艺条件下,Co、Ni、Cu、Mn和Zn的浸出率分别达92.45%、93.48%、89.52%、97.78%和94.79%。经XRD表征,浸出后污泥中未见原污泥中的矿物相,说明原污泥中的矿物几乎全部被溶解。

The valuable metals in the sludge from Ni-Co hydrometallurgy were recovered by the two-stage acidic leaching process. Firstly,Mg and Na were removed using water and sulfate acid as leaching agent under the optimum process conditions of leaching agent pH 7.5,leaching time 5 min and ratio of leaching reagent volume to dried sludge mass（ω） 10 mL/g. Then,the second acidic leaching process was carried out using sulphuric acid as leaching agent and sodium pyrosulfite as reducing agent,and under the optimum process conditions of mass ratio of sulphuric acid to sludge 1.3,mass ratio of sodium pyrosulfite to sludge 0.3,ω 5 mL/g,leaching temperature 85 ℃ and leaching time 20 min,the leaching rate of Co,Ni,Cu ,Mn,Zn reached 92.45%,93.48%,89.52%,97.78%,94.79% ,respectively. The characterization results by XRD showed that the main minerals in the raw sludge disappeared after leaching,which means that most of minerals were dissolved completely.