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以高铁含铟硫酸锌溶液为原料,采用锌焙砂预中和硫酸锌液,在此基础上采用锌粉置换铟富集回收溶液中的铟。在预中和阶段讨论了焙砂用量对预中和后液酸度的影响,以及预中和后溶液酸度对焙砂中铟浸出影响,通过实验获得预中和最佳条件:预中和实验焙砂用量为理论用量的1.4倍,实验温度控制在70~75℃,预中和时间为30 min,预中和后溶液中硫酸浓度大约降至1.2 g·L-1;置换实验过程中溶液的pH值、反应时间、反应温度、锌粉用量等都是影响锌粉置换效果的因素,其中溶液的pH是影响铟的沉淀率的主要因素。实验确定了锌粉置换沉铟的最佳工艺条件为:溶液pH为4.0左右,反应温度80~85℃,反应时间1 h,锌粉用量为6 g·L-1,沉铟后液中In3+的浓度降至3 mg·L-1以下。在此最佳条件下,沉铟率在98%以上,沉铟渣中铟的品位在1.5%~3.0%。通过对置换渣的X衍射图谱(XRD)分析表明置换渣中的铟主要以In(OH)3形式存在。这说明置换过程的实质主要是铟的水解过程,随着置换过程的进行,硫酸锌溶液的酸度下降,促进铟的水解沉淀过程。
High-speed rail indium zinc sulfate solution as raw material, the use of zinc calcine pre-neutralization of zinc sulfate solution, based on the use of zinc powder replacement indium enriched recovery solution of indium. In the pre-neutralization stage, the influence of the amount of calcine on the acidity after pre-neutralization and the acidity of solution after pre-neutralization on the leaching of indium from calcine were discussed. The optimal conditions of pre-neutralization were obtained through experiments: pre-neutralization experiment The amount of sand used was 1.4 times the theoretical amount, the experimental temperature was controlled at 70-75 ℃, the pre-neutralization time was 30 min, and the concentration of sulfuric acid in the solution was reduced to about 1.2 g · L-1 after pre-neutralization. pH value, reaction time, reaction temperature and dosage of zinc powder are all the factors that affect the displacement effect of zinc powder. The pH of the solution is the main factor affecting the precipitation rate of indium. The optimal technological conditions for the zinc-substitution displacement of indium were determined as follows: the solution pH was about 4.0, the reaction temperature was 80-85 ℃, the reaction time was 1 h, the dosage of zinc powder was 6 g · L-1, and the In3 + The concentration dropped below 3 mg · L-1. Under this optimum condition, the indium deposition rate is above 98%, and the indium content in the indium slag is between 1.5% and 3.0%. X-ray diffraction (XRD) analysis of the displacement dross showed that the indium in the displacement dross existed mainly in the form of In (OH) 3. This shows that the essence of the replacement process is mainly indium hydrolysis process, with the replacement process, the acidity of zinc sulfate solution decreased, and promote indium hydrolysis precipitation process.