【作者】 陈玲；

【导师】 陈葵； 周晓葵；

【作者基本信息】 华东理工大学 ， 化学工程， 2015， 硕士

【摘要】 硫酸法钛白粉生产中产生大量硫酸浓度为20%～25%的废硫酸液,简称为钛白废酸。将该废酸用于制备湿法磷酸,既利用了废硫酸液中的有效硫酸,降低了钛白废酸处理成本,又可以降低湿法磷酸的原料生产成本,对环境保护、资源的循环利用具有重要意义。但是由于钛白废硫酸中含有的4%～6%Fe2+对磷酸盐产品质量会造成一定的负面影响,如有效磷损失、色相差等缺点。因此钛白废酸用于湿法磷酸生产过程中必须控制铁含量,限制了钛白废酸的使用。降低废酸中铁离子的含量,是提高钛白废酸利用的关键。本文首先采用平衡法分别测定了硫酸亚铁、硫酸铁在硫酸溶液中的溶解度。利用不同价态铁离子在硫酸中溶解特性及溶解度差异,提出了利用结晶法脱除钛白废酸中铁的工艺研究方法：首先通过浓缩提高废酸中硫酸浓度,使得硫酸亚铁在溶液中过饱和结晶析出；然后通过氧化反应将废硫酸中的Fe2+氧化为Fe3+结晶析出,达到深度除铁的目的。通过实验考察了各操作参数对结晶过程的影响,并确定了最优的结晶工艺操作参数。按照优化后的工艺条件操作钛白废硫酸中总铁含量低于0.2%。根据小试,本文提出了钛白废酸净化除铁工艺路线,在四川龙蟒钛业股份有限公司废酸车间进行工业试验。试验结果表明：本工艺能够有效脱除钛白废酸中的铁,铁的脱除率达到95%,使得钛白废酸中残余铁含量平均下降为0.18%,达到预期的除铁目的。更多还原

【Abstract】 Titanium waste sulfuric acid generated during the production of TiO2with sulfuric acid can be used in the production of wet-process phosphoric acid so as to make the best of the sulfuric acid in the waste sulfuric acid. It can not only reduce the cost of the production of TiO2by sulfuric acid, but also reduce the cost of raw materials of wet-process phosphoric acid, which doubtlessly has great significance to the environmental protection and the improvement of economy. However, there is4%～6%iron in the waste sulfuric acid which has negative effect on the quality of phosphate products such as available phosphorus degradation, caking and poor color. Therefore, the iron content must be strictly controlled when the waste sulfuric acid was used in the production of wet-process phosphoric acid, which restricts the utilization of waste sulfuric acid, In order to increase the usage of white waste acid, iron in waste acid should be removed.The solubility of ferrous sulfate, ferric sulfate in sulfuric acid solution was measured by using the balance method in this paper. According to the solubility of Fe2+and Fe3+in sulfuric acid solution, a new method of removal iron from waste sulfuric acid by crystallization was studied. Firstly the waste sulfuric acid was concentrated to increase the concentration of sulfuric acid in the waste acid, so that the ferrous sulfate could crystal from the waste acid; Then through oxidation reaction to make ferrous sulfate changed to ferric sulfate which would precipitate from the solution by crystallization. The effects of parameters of crystallization were studied and the better operation conditions of crystallization were determined. Under the optimal conditions, the residual iron content in the waste sulfuric acid was lower than0.2%.Based on the experimental research, the process route of removal iron from waste acid was designed. And industrial tests were carried out in waste acid workshop of Sichuan Lomon Titanium Industry Co., Ltd. Results showed that by using this new method, the overall iron removal rate can reach95%, the residual iron content in waste acid drop to an average of0.18%.更多还原