Purification of dissolved impurities removed

According to the solubility of titanium impurities in the hydrolysis of the behavior can be divided into two categories: one type of impurities in the titanium solution hydrolysis process, due to the greater acidity of the titanium solution without hydrolysis, no precipitation, for example, ferrous sulfate is still Exist in the hydrolysis of the mother liquor to maintain the dissolved state, such impurities do not have to be removed in advance of the purification of titanium can be removed by washing Metatitanic acid; Another kind of impurities in titanium hydrolysis reaction with titanium to form a precipitate hydrolysis, or they Metatitanic acid adsorption will be coprecipitation, such impurities if the quality of the final titanium dioxide is harmless, then do not have to purify removed. For example, antimony is harmless to pigmentary titanium dioxide because antimony sulfate is hydrolyzed to form meta-antimonic acid with metatitanic acid precipitated as titanium sulfate is thermally hydrolyzed. When satin burning partial antimony acid also decomposition of white antimony trioxide (also known as antimony white) mixed in titanium dioxide, the performance of the finished product has no effect, so you do not have to remove. If you can affect the quality of titanium dioxide, it must be pre-purification removed. Such as colored lead, diamond, vanadium, chromium, manganese and other metal ions must be removed in advance. Removal methods can be based on the reaction characteristics in the sulfuric acid solution, and targeted purification, for example, antimony, lead, diamond and some other heavy metals, their sulfides are generally insoluble in acidic medium. Purification of the impurity removal method, the acid solution can be leached titanium solution is about to add a small amount of sodium sulfide before the release of heavy metal ions into insoluble sulfide.