【摘要】 提出了碱酸浸出处理铝电解废防渗料的工艺.以某铝厂废防渗料为原料，分析其主要物相为NaF,NaAlSiO₄,CaF₂,α-Al₂O₃,Na₃AlF₆,Si和β-Al₂O₃.首先，原料水浸分离得到质量分数为98.84%的NaF.其次，采用单因素法得到碱浸处理水浸渣的最优工艺条件为温度90℃、液固比5 cm³/g、碱渣质量比0.25、反应时间100 min，该条件下Na₃AlF₆浸出率为94.04%.再次，通过单因素法得到酸浸处理碱浸渣的最优工艺条件为温度58℃、反应时间45 min、酸浓度0.6 mol/L、液固比12 cm³/g，该条件下NaAlSiO₄和CaF₂可被浸出.将碱浸液滴入酸浸液中除去酸浸液中的硅，当pH约为3时酸浸液中硅溶胶沉淀效果最好，过滤后加热硅溶胶，产物主要为SiO₂·0.2Al₂O₃，质量分数为97.20%.将过滤去除硅溶胶后的酸浸液加入碱浸液中沉淀回收氟盐，当pH为9时，CaF₂和Na₃AlF₆的回收率最高，分别为95.91%和92.44%，质量分数分别为48.41%和25.14%，此外，沉淀物中还含有质量分数为25.32%的Al（OH）₃.更多还原

【Abstract】 The process of treating spent dry barrier from aluminum electrolysis with alkali and acid is proposed. Spent dry barrier sample from an aluminum company was taken as the raw material, and its main phases are NaF, NaAlSiO₄, CaF₂, α-Al₂O₃, Na₃AlF₆, Si and β-Al₂O₃. Firstly, the NaF with mass fraction of 98. 84% is obtained by water leaching separation of the raw materials. Secondly, the optimal process condition for alkali leaching treatment of water leaching residue were obtained by single factor method as follows: temperature of 90 ℃, liquid-solid ratio of 5 cm³/g, alkali-slag mass ratio of 0. 25, and reaction time of 100 min, and under this condition, the leaching rate of Na₃AlF₆ was 94. 04%. After that, the optimal process conditions for acid leaching treatment of alkali leaching residue were obtained by single factor method as follows: temperature of 58 ℃, reaction time of 45 min, acid concentration of 0. 6 mol/L, and liquidsolid ratio of 12 cm³/g, and under this condition, NaAlSiO₄ and CaF₂ can be leached. Subsequently, the alkali leaching solution was dropped into the acid leaching solution to remove silicon in the acid leaching solution. It was found that when the pH was about 3, the precipitation effect of silica sol in the acid leaching solution was the best, and the product obtained by heating the silica sol which was obtained through filtering was mainly SiO₂·0. 2Al₂O₃, with a mass fraction of 97. 20%. The acid leaching solution after filtering to remove the silica sol was added to the alkali leaching solution to precipitate and recover the fluoride salts, and it was found that when the pH was 9, the recovery rates of CaF₂ and Na₃AlF₆ were the highest, which were 95. 91% and 92. 44%, respectively, and the mass fractions were 48. 41% and 25. 14%, respectively. In addition, the precipitate contains 25. 32%（mass fraction） of Al（OH）₃.更多还原