(內(nèi)蒙古科技大學(xué) 材料與冶金學(xué)院，包頭 014010)
摘 要: 包頭混合稀土精礦絡(luò)合浸出分離稀土后的廢液中含有大量的鋁離子，經(jīng)過(guò)特殊的工藝技術(shù)能夠?qū)U水中大量的鋁合成冰晶石，但該冰晶石中的硅含量超標(biāo)，發(fā)現(xiàn)采用硫酸-氫氟酸-鹽酸的混酸可以有效地脫除冰晶石中硅的化合物。確定以下優(yōu)化的脫硅條件：硫酸濃度0.4 mol/L、氫氟酸濃度0.8 mol/L、鹽酸濃度0.4 mol/L、反應(yīng)時(shí)間90 min、反應(yīng)溫度80 ℃、液固比5:1；在該條件下硅的脫除率達(dá)到74.24%，除硅后冰晶石中硅的含量為0.23%，達(dá)到冰晶石國(guó)家標(biāo)準(zhǔn)要求。XRD分析結(jié)果表明大部分硅和雜質(zhì)已經(jīng)被脫除；SEM測(cè)試結(jié)果表明混酸法脫除冰晶石中硅的過(guò)程中使冰晶石分散性變好，而冰晶石本身的化學(xué)結(jié)構(gòu)并沒(méi)有被破壞。
關(guān)鍵字: 絡(luò)合浸出；廢液；冰晶石；脫硅
（School of Material and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, China）
Abstract:After rare earth separation by complexation extraction from Baotou mixed rare earth concentrate, the obtained waste liquid contains a large number of aluminum ions. The aluminum ions in waste liquid can be transformed into cryolite through a special processing technology, but the content of silicon in cryolite exceeds the content required in Chinese national standard. The compounds of silicon could be removed by the mixture of H2SO4-HF-HCl. The optimized conditions for removing silicon are obtained as follows: 0.4 mol/L HCl, 0.8 mol/L H2SO4, and 0.4 mol/L HCl for 90 min reaction at 85 ℃ under the liquid-solid ratio of 5:1. The removal rate of silicon reaches 74.24% under the optimized conditions. The content of silicon in the cryolite after desilication is 0.23%, which meets the requirement of the content of silicon in cryolite in Chinese national standard. XRD results indicate that most of the silicon and impurities is removed. SEM images show that, during the process of desilication, the dispersity of cryolite is enhanced while the chemical structure of cryolite is maintained.
Key words: complexation extraction; waste liquid; cryolite; removing silicon
