Abstract: <SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman"; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">Suspension crystallization and inclined column crystallization were adopted respectively to purify phosphoric acid with industrial grade phosphoric acid as raw material.Impurity removal effect of suspension crystallization was investigated by taking iron,fluorine,sulfate radical,chlorine,magnesium,and potassium as representatives.Results showed that impurity contents in phosphoric acid decreased with the increase of suspension crystallization repetition.After five times of crystallization,Fe<SUP>3+</SUP>content in phosphoric acid decreased from 349.9 mg/kg to 2.7 mg/kg,F<SUP>-</SUP>content decreased from 55.9 mg/kg to 0.6 mg/kg, SO<SUP>2- </SUP>4 content decreased from 1 047.4 mg/kg to 0.5 mg/kg,K<SUP>+</SUP> content decreased from 87.1 mg/kg to 9.1 mg/kg, Mg<SUP>2+ </SUP>content decreased from 153.9 mg/kg to 7.8 mg/kg,and Cl<SUP>- </SUP>content decreased from 250.4 mg/kg to 7.6 mg/kg. Impurity removal effect of inclined column crystallization was also investigated by taking Fe<SUP>3+ </SUP>as representative.Results showed that purifying effect of inclined column crystallization was equal to 1.9 times of suspension crystallization.</SPAN>