利用硫酸镍制备超细球形镍粉的实验研究

针对硫酸镍液相通氢还原制得球状超细镍粉品位较低（仅在96%左右）的问题，提出一条通过火法-湿法联合还原提高镍粉品位的工艺路线。首先由硫酸镍和氢氧化钠水溶液在室温下混合而成氢氧化镍浆料，不经过过滤洗涤，转入高压釜进行悬浮态氢还原。反应结束后，液固分离，获得品位在96%左右的半成品镍粉。将半成品镍粉在氢还原炉中进行二次还原，控制还原温度为400 ℃，还原时间为2 h，获得的产品镍质量分数大于99.5%，粒度小于2.0 μm，满足金刚石工具、硬质合金等行业需求的超细镍粉性能指标要求。

Experiment research on preparation of ultrafine spherical nickel powder from nickel sulfate

In allusion to the problem that the grade of ultrafine spherical Ni powder was very low（only about 96%） prepared from nickel sulfate by liquid hydrogen reduction process，a combined process of pyro-and hydro-metallurgy was introduced in order to improve the grade of Ni powder.Firstly，mix the nickel sulfate with sodium hydroxide solution to prepare nickel hydroxide slurry at room temperature.Without washing and filtering，the slurry was put into the high-pressure reactor where the hydrogen reduction reaction happened in a suspended state.After the reaction，simi-finished Ni powder with about 96% was obtained through liquid solid separation.Then the secondary reduction was carried out in a hydrogen reduction furnace. Under the conditions of reduction temperature 400 ℃ and reduction time 2 h，the product′s mass fraction of Ni was over 99.5% and product′s particle size was less than 2.0 μm，which could meet requirements of performance indexes of diamond tools and cemented carbide industries.