Kinetic study of high-pressure acid leaching of Mg and Ni from serpentine

Inner Mongolian serpentine ore was subjected to sulfuric acid leaching tests,and the effects of the leaching process parameters on the leaching efficiency of different metals were investigated.The leaching efficiency of Mg,Fe,Al,Ni,and Co reaches 93.98%,60.09%,82.08%,90.58%,and 94.06%,respectively,under the leaching conditions of 5 mol/L H_(2)SO_(4),liquid/solid ratio of 4 mL/g,and leaching temperature 100℃.Hence,the valuable metals in serpentine were effectively recovered by sulfuric acid leaching.The leaching behaviors of Mg,Fe,and a small amount of Al were analyzed using X-ray diffraction.The results show that the unreacted Mg and Fe remained as MgFe_(2)O_(4),and Al formed Al_(2)Si_(2)O_(5)(OH)_(4) in the leaching residue.The kinetics of Mg and Ni in the leaching process was studied respectively.The leaching kinetics of Mg conformed to the shrinking core model with an activation energy of 16.95 kJ/mol,which was controlled by the combination of the diffusion and chemical reaction.The leaching kinetics of Ni accorded with the Avrami equation with an activation energy of 11.57 kJ/mol,which was controlled by diffusion.In the study,the valuable metal elements were extracted from serpentine minerals with high efficiency and low cost,which possessed important practical values.

以海底多金属锰结核制备三元正极材料前驱体Ni0.5Co0.2Mn0.3(OH)2

以海底多金属结核资源为原料,采用硫酸浸出−净化除杂−配合沉淀的工艺制备三元正极材料前驱体Ni0.5Co0.2Mn0.3(OH)2。在硫酸浸出过程中,考察温度、液固比、硫酸浓度、浸出时间对镍、钴、锰浸出率的影响,探究镍、钴、锰元素浸出动力学。结果表明:在温度200℃、液固比6:1、硫酸浓度350 g/L、浸出时间90 min条件下,镍、钴浸出率达到95%以上,锰浸出率仅为6.43%,实现镍、钴与少部分锰的浸出。当温度在120~200℃之间时,锰浸出过程受扩散控制,表观活化能为10.64 kJ/mol;镍、钴浸出过程受混合控制,表观活化能分别为27.60和38.16 kJ/mol。浸出液经黄钠铁矾法除铁、硫化锰除铜、碳酸氢铵水解沉淀除铝、P204萃取除钙后,采用P204萃取镍、钴、锰,得到硫酸镍、硫酸钴和硫酸锰的混合液,经调节镍钴锰比例后,用氨水−氢氧化钠配合共沉淀法制备得到球形的Ni0.5Co0.2Mn0.3(OH)2,可用于制备三元正极材料。