盐酸分级浸出赤泥中有价金属元素

Stepwise leaching of valuable metals from red mud using hydrochloric acid

采用盐酸2段分级浸出工艺回收氧化铝赤泥中的有价金属元素。通过考察液固比、反应温度、反应时间及盐酸使用量对浸出率的影响,确定了2段浸出的实验工艺。结果表明:在盐酸用量为理论用量的40%、90℃液固比为7∶1、反应时间1 h的条件下,Ca的浸出率为96.2%,Na的浸出率为82.47%,Al的浸出率为42.87%,其他元素几乎不浸出,这是第1段浸出;在盐酸用量为理论量的130%、90℃、盐酸浓度8.8 mol·L^(-1)的条件下,浸出1段酸浸渣,Fe的浸出率99.65%,Sc的浸出率88.76%,V的浸出率93.58%,其他稀土元素的浸出率均达到了70%左右,这是第2段浸出。

In our study, a two-step leaching method was developed for valuable metal recovery from red mud by hydrochloric acid. By investigating the effect of liquid to solid ratio, reaction temperature, reaction time and the amount of hydrochloric acid on the leaching efficiency, the two-step leaching program was established. During the first stage, the addition amount of hydrochloric acid was 40% of theoretical values, and the reaction tempera- ture and time were 90℃ and 1 h, respectively, with liquid-solid ratio as 7 ： 1. The leaching efficiencies of Ca, Na and A1 were 96.2% , 82.47% and 42.87% , respectively, and almost no other elements was leached at this stage. During the second stage, the amount of hydrochloric acid was 130% of theoretical values, the reaction time was 90℃ , and the concentration of hydrochloric acid was 8.8 mol· L-1. The leaching residue from the first stage was further leached in this stage, and the leaching efficiencies of Fe, Sc, and V were 99.65% , 88.76% and 93.58% . Furthermore, the leaching effieiencies of all other rare earth elements were above 70%.