高镁低品位铜镍矿氧压硫酸浸出液综合回收研究

Comprehensive Recovery of Metals from Sulfuric Acid Solutions Left After Oxygen-Pressure Leaching of High-Magnesium and Low-Grade Copper-Nickel Ore

针对高镁低品位铜镍矿氧压硫酸浸出液特点,提出“Lix984萃取提铜-MgO中和黄钠铁矾法沉淀除铁-MgO中和沉镍”综合回收工艺。结果表明,采用Lix984可选择性萃取99.79%的铜,其他金属离子基本不萃取,经模拟工业贫铜电解液反萃,铜反萃率达98.13%,得到富铜电解液,可电积制备金属铜;萃铜余液通过MgO中和黄钠铁矾法沉淀除铁,铁沉淀率达99.20%,镍损失率仅0.60%;沉铁后液通过MgO中和沉淀回收镍,镍沉淀率为99.91%,并得到镍含量24.13%的氢氧化镍粗产品;沉镍后的高浓度硫酸镁沉淀后液,可用于回收镁。

In view of the characteristics of solution left after sulfuric acid oxygen-pressure leaching of high-magnesium and low-grade copper-nickel ore, a separation and recovery process was proposed, consisting of copper extraction with Lix984, iron precipitation by neutralization of sodium jarosite with MgO, and nickel precipitation by MgO neutralization. Experiment results showed that 99.79% of the copper in the solution was selectively extracted and recovered with Lix984, while no other metal ions were extracted. In an experiment, the simulated industrial poor-copper electrolyte was taken for stripping, showing the stripping rate of copper up to 98.13%, and the obtained copper-rich electrolyte was then used to prepare copper powder by electrodeposition. The raffinate obtained after copper extraction was treated by neutralization of sodium jarosite with MgO for iron removal, resulting in the iron precipitation rate up to 99.20% and nickel losses of 0.60%. Then, the obtained solution after iron precipitation was treated by MgO neutralization for nickel recovery, leading to the nickel precipitation rate up to 99.91% and the obtained crude nickel hydroxide product with a nickel content of 24.13%. After that, the solution left, due to the high concentration of magnesium sulfate, could be further used to recover magnesium.