机械活化辅助浸出硫化镍矿中有价金属

随着高镍三元锂电池在新能源电动汽车领域的规模化应用，全球镍资源的需求量日益增加，绿色、高效、低成本地从硫化镍矿资源中提取镍的技术备受关注。本工作提出了机械活化辅助氧化浸出硫化镍矿的提取路径，在机械活化过程中通过改变硫化镍矿结构、增加晶体无序化程度、减小粒度和增加比表面积增加硫化镍矿的反应活性，再通过Na2S2O8氧化浸出实现了常压环境中硫化镍矿中有价金属的高效浸出。考察了机械活化和浸出过程中各因素对硫化镍精矿浸出的影响，确定了较优条件。在较优条件球磨转速613 r/min、球料比20:1、球磨时间120 min、酸浓度2 mol/L、过硫酸钠浓度0.42 mol/L、浸出时间60 min、液固比5:1、搅拌速率400 r/min和浸出温度80℃下，Ni, Co, Cu和Fe的浸出率分别达98.9%, 97.7%, 98.2%和98.7%。

Leaching of valuable metals from nickel sulfide ores by mechanical activation

The demand for nickel resources has increased significantly in recent years due to the large-scale application of high-nickel ternary lithium batteries in the field of new energy electric vehicles. To alleviate the shortage of nickel resources in China, the nickel extraction from nickel-containing minerals has received widely attention. As an important nickel-containing minerals, the composition of nickel sulfide ore is complex and it is difficult to be leaching under atmospheric conditions. Therefore, green, high efficient, and low-cost technologies for extracting nickel from nickel sulfide ore resources have attracted much attention. In this work, the mechanical activation was introduced to increase the reactivity of nickel sulfide ore, then Na2S2O8 was used to leaching activated nickel sulfide ore under atmospheric conditions. Various conditions including rotation speed, ball-to-material ratio and ball milling time as well as the acid concentration, oxidation concentration, leaching time, liquid-to-solid ratio, stirring rate and temperature in the leaching process were optimized and the mechanism was further discussed. It was found that the mechanical activation process reduced the particle size and increased the degree of amorphization of nickel sulfide ore resulting in an increase in its reactivity, and the leaching process converted part of the S2- to sulfur by Na2S2O8 reducing the release of harmful gas H2S during the reaction. At the optimal conditions (rotation speed of 613 r/min, ball-to-material ratio of 20:1, ball milling time of 120 min, acid concentration of 2 mol/L, Na2S2O8 concentration of 0.42 mol/L, leaching time of 60 min, liquid-to-solid ratio of 5:1, stirring rate of 400 r/min and temperature of 80℃), leaching rate of Ni, Co, Cu and Fe were 98.9%, 97.7%, 98.2% and 98.7%, respectively, while the content of Ni, Co and Cu in residues were 0.45%, 0.03% and 0.14%, respectively. With this research, it was expected to provide theoretical and technical support for the efficient extraction of valuable metals from nickel sulfide ores.