Effects of seed crystal concentration, pH, and stirring rate on ammonium sulfate crystallization under the action of ammonium nitrate

Abstract

In order to explore the effect of ammonium nitrate on the crystallization of ammonium sulfate mother liquor, this paper selected crystal seed, pH and stirring rate as the influencing factors, and studied the changes of average particle size, morphology and phase structure of ammonium sulfate crystals under the action of ammonium nitrate. When the seed crystal concentration was 1%–2%, the solute growth of the mixed solution could effectively reduce the supersaturation during the evaporation process, and the crystal growth did not generate new crystal nuclei, interfering with the crystallization process. A pH value of 4–5 promotes solvent/crystal surface interaction and crystal surface growth, which is beneficial for obtaining high-quality crystals. At a stirring rate of 200–300 r/min, the nucleation rate and secondary nucleation were improved, which is conducive to solid–liquid separation.