用离子色谱法测定了脱硫石膏粉中硫酸根的含量,并以此换算成硫酸钙的质量分数。样品(0.050 0 g)溶于盐酸(1+1)溶液0.5 mL中,于容量瓶中定容为100 mL,静置24 h后定量移取部分上清液稀释25倍。分取20 μL进样作离子色谱分析。样液经过Metrosep A SUPP1柱净化,流出液通过Metrosep A SUPP5阴离子交换柱,以含1.8 mmol·L-1碳酸钠溶液和1.7 mmol·L-1碳酸氢钠溶液的混合溶液为流动相进行淋洗,采用抑制电导检测。以实际样品为基体在2个浓度水平上加入硫酸根标准溶液进行回收试验,测得回收率大于95%。对同一样品作8次测定,测定值的相对标准偏差小于1%。

Ion chromatography was applied to the determination of SO42- ion in desulfurized gypsum powder, and content of CaSO4 (in w%) was calculated from the amount of SO42- found. The sample (0.050 0 g) was dissolved with 0.5 mL of HCl (1+1) solution and the solution with the insoluble residue was made up to 100 mL in a volumetric flask. An aliquot of the supernatant was used for IC analysis. The sample solution was purified by passing through Metrosep A SUPP1 column, and the eluate was separated on the Metrosep A SUPP5 anion exchange column, with a mixed solution containing 1.8 mmol·L-1 Na2CO3 and 1.7 mmol·L-1 NaHCO3 as eluant. Inhibitory conductivity detection was adopted in the analysis. Recovery was tested by addition of SO42- standard solution at 2 concentration levels to a gypsum sample as matrix, giving values of recovery greater than 95%. Value of RSD (n=8) calculated from the analytical results obtained by analyzing a gypsum sample by the present method was less than 1%.