METHOD FOR PRE-TREATING PHOSPHORUS ROCK BY MIXTURE OF TITANIUM DIOXIDE WASTE ACID AND FLUORINE-CONTAINING WASTE WATER

摘要

Provided is a method for pre-treating phosphorus rock by a mixture of titanium dioxide waste acid and fluorine-containing waste water. The method comprises a step of enabling an acid solution and phosphorus rock pulp having solid content being more than 75% to react in an reaction tank to obtain reaction slurry and a step of performing solid-liquid separation on the reaction slurry. The acid solution is prepared through the following steps: (1) collecting titanium dioxide waste acid, obtained in sulfate-based titanium dioxide production, to a waste acid storage tank, controlling content of sulfuric acid in the titanium dioxide waste acid to be 20-30%, and content of ferrous sulfate to be 10-14%; (2) mixing the fluorine-containing waste water and the titanium dioxide waste acid according to the mass ratio of (4-10):1 to obtain an acid solution. By means of the method, post-treatment cost of the titanium dioxide waste acid and the fluorine-containing waste water is reduced on the conditions of high magnesium removing rate and low phosphorus loss rate; meanwhile, the problem that a pre-treatment pH value is influenced by the fluctuation of the acid concentration of the acid waste water in a process of pre-treating the phosphorus rock is solved; and the method is suitable for wet-process phosphoric acid production.