Process for bleaching metatitanic acid by using sodium citrate method

Abstract

The invention discloses a process for bleaching metatitanic acid by using a sodium citrate method. To solve defects of conventional methods, metal ions, particularly ferric iron ions, in metatitanic acid which is subjected to one time of water washing are bleached by using the sodium citrate method. The process is simple to operate, free of multiple times of material feeding, low in energy consumption, relatively small in sulfuric acid amount and short in bleaching process when being compared with conventional aluminum zinc bleaching, moreover short in reduction time, low in operation temperature, good in bleaching effect and free of residual pollution by using the sodium citrate method, and relatively applicable to industrial production and free of secondary pollution when being compared with EDTA-2Na (Ethylene Diamine Tetraacetic Acid-2Na) bleaching.

Description

technical field [0001] The invention generally relates to a process for bleaching metatitanic acid, in particular to a process for bleaching metatitanic acid by sodium citrate method. Background technique [0002] At present, in order to remove impurities in metatitanic acid in sulfuric acid titanium dioxide process, it needs to go through a process of washing, bleaching and washing twice. In the domestic production of sulfuric acid titanium dioxide, Trace iron in the metatitanic acid exists in the form of solid ferric hydroxide after the first wash, the content of iron impurities is above 0.009%, and bleaching is the main step. [0003] Sodium citrate has metal ion complexing ability, has good complexing ability to metal ions such as Ca2+ and Mg2+, and also has good complexing ability to other metal ions, such as Fe2+ ions, and has excellent solubility, and dissolves Sexuality increases with increasing water temperature. It is a salt of weak acid and strong base, which ...

AI Technical Summary

Problems solved by technology

[0004] At present, the bleaching methods widely used in industry include aluminum powder bleaching and trivalent titanium bleaching. The process of aluminum powder bleaching is a liquid-solid reaction, which takes a long time, easily leaves residue, and has a certain impact on quality; trivalent titanium bleaching often requires additional equipment, etc. , the process is long, the acid consumption is the largest, and the cost is high, so the bleaching and iron removal method needs further optimization and reform