钛白粉生产硫酸废液中铁的脱除过程研究

发布时间：2018-03-13 12:20

本文选题：废硫酸液　切入点：硫酸亚铁　出处：《华东理工大学》2015年硕士论文　论文类型：学位论文

【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。
[Abstract]:In the production of titanium dioxide by sulphuric acid process, a large amount of waste sulfuric acid with a concentration of 20% or 25% is produced, which is referred to as the waste acid of titanium dioxide. The waste acid is used to produce wet process phosphoric acid, which not only utilizes the available sulfuric acid in the waste sulfuric acid solution, but also reduces the cost of treating waste acid of titanium dioxide. It can also reduce the production cost of wet phosphoric acid, which is of great significance for environmental protection and recycling of resources. However, the 462% of waste sulfuric acid contained in titanium dioxide waste sulfuric acid will have a negative effect on the quality of phosphate products. Therefore, the content of iron must be controlled in the process of wet phosphoric acid production, which limits the use of waste acid of titanium dioxide. Reducing the content of iron ion in waste acid is the key to improve the utilization of waste acid of titanium white. In this paper, the solubility of ferrous sulfate and ferric sulfate in sulfuric acid solution was determined by equilibrium method. The process of removing iron from titanium white waste acid by crystallization was put forward. Firstly, the concentration of sulfuric acid in waste acid was increased by concentration, so that ferrous sulfate was precipitated in solution by supersaturated crystallization. Then the Fe2 in waste sulfuric acid was oxidized into Fe3 crystal by oxidation reaction, and the purpose of deep iron removal was achieved. The effect of operation parameters on the crystallization process was investigated experimentally. The optimum operation parameters of crystallization process were determined and the total iron content of titanium dioxide waste sulfuric acid was less than 0.2 according to the optimized technological conditions. According to the small scale test, the technical route of titanium dioxide waste acid purification and iron removal is put forward, and the industrial test is carried out in the waste acid workshop of Sichuan Dragon python Titanium Industry Co., Ltd. The results show that this process can effectively remove iron from titanium white waste acid. The removal rate of iron reached 95%, which reduced the content of residual iron in titanium white waste acid to 0.18 on average, which achieved the expected purpose of iron removal.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X788;TQ126.35

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