Abstract: <SPAN lang=EN-US>Technology of preparing strontium carbonate by double decomposition from celestite concentrate powder was investigated.Results indicated that the maximal SrSO</SPAN><SPAN lang=EN-US><SUB>4</SUB> conversion rate reached 95.77%,and the average purity of strontium carbonate could reach 99.5% when Na</SPAN><SPAN lang=EN-US><SUB>2</SUB>CO</SPAN><SPAN lang=EN-US><SUB>3</SUB> was used as the converter and NH</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman""></SPAN><SPAN lang=EN-US>3</SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"">·</SPAN><SPAN lang=EN-US>H</SPAN><SPAN lang=EN-US><SUB>2</SUB>O-(NH</SPAN><SPAN lang=EN-US><SUB>4</SUB>)</SPAN><SPAN lang=EN-US><SUB>2</SUB>SO</SPAN><SPAN lang=EN-US><SUB>4 </SUB>as buffer solution to adjust pH of reaction system and as inhibitor to inhibit the conversion of Ba</SPAN><SPAN lang=EN-US><SUP>2+</SUP></SPAN><SPAN lang=EN-US>in the system.CO</SPAN><SPAN lang=EN-US><SUP>2-</SUP></SPAN><SPAN lang=EN-US><SUB>3</SUB> was the actual conversion agent in this reaction system.CO<SPAN lang=EN-US><SUP>2-</SUP></SPAN><SPAN lang=EN-US><SUB>3</SUB></SPAN></SPAN><SPAN lang=EN-US> took up the dominate position when pH was higher than 10.5,which favored the conversion of the SrSO</SPAN><SPAN lang=EN-US><SUB>4</SUB>.However,when pH was lowered to 8.5,CO<SPAN lang=EN-US><SUP>2-</SUP></SPAN><SPAN lang=EN-US><SUB>3</SUB></SPAN></SPAN><SPAN lang=EN-US> amount-of-substance fraction in liquor almost decreased to zero and SrSO<SPAN lang=EN-US><SUB>4</SUB></SPAN></SPAN><SPAN lang=EN-US> conversion reaction therefore tended to stop.Experimental results showed that when temperature was </SPAN><?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="75" UnitName="℃"><SPAN lang=EN-US>75 </SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"">℃</SPAN></st1:chmetcnv><SPAN lang=EN-US>,</SPAN><SPAN lang=EN-US>Na</SPAN><SPAN lang=EN-US><SUB>2</SUB>CO</SPAN><SPAN lang=EN-US><SUB>3 </SUB>density was 1.2 mol/L,and pH of the solution was kept more than 10.5,it was beneficial to the conversion of the SrSO</SPAN><SPAN lang=EN-US><SUB>4</SUB>.In the experiment,NH</SPAN><SPAN lang=EN-US><SUB>3</SUB></SPAN><SPAN style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"">·</SPAN><SPAN lang=EN-US>H</SPAN><SPAN lang=EN-US><SUB>2</SUB>O-(NH</SPAN><SPAN lang=EN-US><SUB>4</SUB>)</SPAN><SPAN lang=EN-US><SUB>2</SUB>SO</SPAN><SPAN lang=EN-US><SUB>4 </SUB>buffer solution has the promoter action to reaction.<BR></SPAN>