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">Separation efficiency of impurities,such as arsenic,iron,calcium,and magnesium,was studied in the process of purifying phosphoric acid by zone melting method,especially for the separation of arsenic.Effects of zone melting times and moving speed of melting zone on purification efficiency were preliminarily studied.Experimental results indicated arsenic,iron,calcium and magnesium in phosphoric acid were accumulated to the end of melting zone along with its moving direction;arsenic in phosphoric acid was apparently separated via only one zone melting operation;ratio of arsenic content between the end and the beginning of zone melting was 1.52 and it raised along with the increasing of zone melting times;after five times zone melting,ratio of arsenic content between the end and the beginning reached the maximum of 3.33;separation efficiency of impurities was also raised by lowering the moving speed of melting zone;when the moving speed of melting zone was 20 mm/h,ratio of arsenic content between the end and the beginning reached 1.25;while the moving speed of melting zone was reduced to 10 mm/h,ratio of arsenic content between the end and the beginning increased to 3.3;to lower the moving speed of melting zone again,separation efficiency didn</SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman"; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">′</SPAN><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">t have an apparent increase any more.</SPAN>