包头混合型稀土矿盐酸洗钙工艺研究

Study on Technique for Calcium Removal from Mixed Rare Earth by HCl

研究了采用盐酸洗钙工艺除去直接碱分解65%高品位混合型稀土精矿中的钙杂质,省去传统碱法中的化选除钙工艺,实现连续化生产。考察了酸洗除钙过程中浸出条件对钙去除率和稀土损失率的影响规律,并通过矿浆浓度、起始酸度、酸量、温度等条件得出盐酸洗钙的最优工艺条件,结果表明,在矿浆浓度为16.67%,起始酸度为3.5 mol/L,水洗矿耗酸量为1.33 mol/kg,浸出温度为40℃的酸洗条件下,Ca O的去除率可达到70%以上,REO基本不损失,符合稀土料液对钙杂质含量的要求。

This paper researched the new technology for calcium removal by hydrochloric acid from 65% high-grade mixed rare earth concentrate after direct alkali decomposition to replace chemical process for calcium removal and realize continuous production. The conditions affecting calcium removal and rare earth leaching ratio in the process including the pulp density, ini- tial acidity ,the amount of HCl and leaching temperature were investigated. The results indicated that when the pulp density was 16. 67%, initial acidity was 3.5 mol/L, the amount of HCl was 1.33 mol/kg（washed ore）, and the leaching temperature was 40 ℃, the calcium leaching rate was greater than 70%, the rare earth was almost not leached. The results meet the re- quirement of calcium impurities in the feed solution.