风化壳淋积型稀土矿除杂渣中分步回收稀土和铝的研究

提出了一种从风化壳淋积型稀土矿除杂渣中分步浸出回收稀土和铝的工艺。在40 ℃、液固比10∶1条件下用8 mol/L NaOH浸出除杂渣，铝浸出率约为96%，而稀土仍保留在滤渣中。再在40 ℃、液固比10∶1条件下用1 mol/L HCl浸出碱浸后的滤渣，稀土La和Y浸出率分别达87.09%和72.01%。酸浸液经草酸沉淀得草酸稀土，滤液与碱浸液混合得氢氧化铝，稀土和铝总回收率分别为78%和97%。该工艺对资源利用和环境保护具有重要意义。

Stepwise Recovery of Rare Earth and Aluminum from Impurities Removed Residue of Weathered Crust Elution-Deposited Rare Earth Ore

A stepwise leaching technique was proposed for recovery of rare earth and aluminum from the residue left after impurities were removed from weathered crust elution-deposited rare earth ore. This residue was leached with 8 mol/L NaOH at 40 ℃ with the liquid-solid ratio of 10∶1, resulting in the leaching efficiency of aluminum reaching 96% and the rare earth almost retained in the residue. Then, the filtered residue after the alkali leaching was leached with 1 mol/L HCl at 40 ℃ with the liquid-solid ratio of 10∶1, leading to the leaching efficiencies of La and Y reaching 87.09% and 72.01%, respectively. The acid leaching solution was then precipitated with oxalic acid to obtain rare earth oxalate. The filtrate was mixed with the alkali leaching solution to obtain aluminum hydroxide, showing the total recovery rates of rare earth and aluminum were about 78% and 97%, respectively. It is concluded that this technique is of significant importance for resource utilization and environment protection.