农药氟虫腈与钛白粉副产盐资源化生产电池用磷酸铁工艺

In response to the challenge of disposing by-product salts during pesticide fipronil and titanium dioxide production processes, a process to synthesis battery grade iron phosphate was proposed utilizing by-product sodium phosphate as the phosphorus source and by-product ferrous sulfate as the iron source. Sodium sulfite in sodium phosphate wastes was oxidized to sodium sulfate through a continuous catalytic oxidation method. The purified ferrous sulfate was oxidized to ferric sulfate by hydrogen peroxide, and then reacted with the aforementioned sodium phosphate to yield iron phosphate. The results show that the oxidation rate of sodium sulfite is close to 100%. After chemical purification and hydrolytic purification, the mass fraction of impurities such as magnesium, manganese, and titanium in the by-product ferrous sulfate was reduced to below 80 mg.kg^-1, and the impurity aluminum was completely removed. Various indicators of the prepared dihydrate iron phosphate meet the requirements outlined in the standard HG/T 4701-2021"Iron phosphate for batteries".