Abstract: <SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman"; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">Calcium sulfate whiskers were prepared by atmospheric acidification method with phosphogypsum and sulfuric acid as raw materials.Effects of the dosage of sulfuric acid,reaction time,reaction temperature,and dosage of phosphogypsum on calcium sulfate whiskers were investigated.By range analysis,the optimized process conditions were obtained as follows: reaction temperature was <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><st1:chmetcnv w:st="on" TCSC="0" NumberType="1" Negative="False" HasSpace="True" SourceValue="103" UnitName="℃">103 <SPAN lang=EN-US style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman""><SPAN lang=EN-US>℃</SPAN></SPAN></st1:chmetcnv>,the reaction time was 30 min,stirring speed was 280 r/min,mass ratio of raw materials (i.e.phosphogypsum to sulfuric acid to water) was 1</SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman"; 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-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">4.6</SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman"; 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-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">35.Under these conditions,yield of whiskers reached 31.36%,average aspect ratio of whiskers was 95,white content was 65.8%,and purity of calcium sulfate reached </SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman"; 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-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">93.61%.</SPAN>