Method for producing nanometer lithopone from electrolytic zinc acid leaching residue

A method for producing nanometer lithopone from electrolytic zinc acid leaching residue comprising:

• 1) leaching, wherein the electrolytic zinc acid leaching residue is leached out by an ammonia-ammonium sulfate solution, the ammonia concentration is 5.5˜7.0 mol/L and the ammonium sulfate concentration is 0˜1 mol/L in said ammonia-ammonium sulfate solution, the leaching temperature is 20˜50° C., and the leaching time is 3 h˜9 h;
• thus obtaining final leached solution;
• 2) purifying, including adding ammonium persulfate to said final leached solution to remove iron by oxidation method one time, and adding activated carbon to remove arsenic by adsorbing of the arsenic and iron precipitation, adding polyacrylamide flocculating agent before filtration separation, and then adding alkali sulfide to the solution of after oxidation to remove impurity, and then separating the solution to obtain filtrate, then replacing the heavy metal elements in the filtrate by using zinc powder, obtaining the zinc sulfate ammonia complex refining liquid;
• 3) processing metathetical reaction, including dissolving sulfide in distilled water to get clear and transparent metathesis solution, adding non-ionic surfactant and mixing evenly, and then adding to said zinc sulfate ammonia complex refining liquid for metathetical reaction, obtaining lithopone emulsion, separating said emulsion by method of filtration to obtain ammonia solution and nZnS—BaSO4 crystalline filter cake, wherein said sulfide is barium sulfide, wherein said ammonia solution returns to the step of leaching after adjusting the ammonia concentration to said concentration;
• 4) washing and smashing, including washing said nZnS—BaSO4 crystalline filter cake by distilled water or ethanol, then separating by method of filtration, and then drying and smashing, and obtaining the nanometer lithopone product.