硫酸钡重量法测定硫磺包芯线中硫

试样以过氧化钠-无水碳酸钠熔融,以蒸馏水浸取,将氢氧化物及磷酸盐等沉淀过滤除去,滤液以盐酸中和变为微酸性,加入氯化钡溶液使硫酸根定量生成硫酸钡沉淀,将沉淀过滤、灰化、灼烧、称量,计算硫的质量分数,从而实现了硫酸钡重量法对硫磺包芯线中硫含量的测定。研究表明:稀释比为40∶1,700 ℃熔融15 min,硫转化完全。沉淀条件表明:在0.5%～1%盐酸(体积分数)及微沸搅拌状态下缓缓加入氯化钡溶液,75～85 ℃温度下陈化1 h即可得到稳定准确的结果。方法用于实际样品分析,结果同GB/T 2449—2006(工业硫磺 差减法)测定值一致,相对标准偏差(RSD,n=6)小于0.20%。实验方法具有相对节约时间、实验室配置条件要求较低及成本较低的特点,更适用于硫磺包芯线中硫含量的常规检测。

Determination of sulfur in sulfur cored wire by barium sulfate gravimetric method

The sample was fused with sodium peroxide and anhydrous sodium carbonate followed by leaching with the distilled water. The hydroxide and phosphate precipitates were removed by filtration. The filtrate was neutralized to slightly acidic with hydrochloric acid. The barium chloride solution was added to quantitatively change the sulfate to the barium sulfate precipitate. The generated precipitate was treated by filtration, ashing, ignition and weighing to calculate the mass fraction of sulfur. Therefore, the determination of sulfur content in sulfur cored wire by barium sulfate gravimetric method was realized. The results indicated that the conversion of sulfur was complete when the sample was fused at 700 ℃ for 15 min with dilution ratio of 40∶1. The precipitation conditions showed that the stable and accurate results could be obtained when the barium chloride solution was slowly added at sub-boiling and stirring states in presence of 0.5%-1% hydrochloric acid (volume fraction). The aging time was 1 h at 75-85 ℃. The proposed method was applied to the analysis of actual samples, and the found results were consistent with those obtained by GB/T 2449-2006 (Industrial sulfur-subtraction method). The relative standard deviations (RSD, n=6) were less than 0.20%. The proposed method exhibited some advantages such as time saving, relatively low laboratory conditions and low cost. It was more applicable for the conventional detection of sulfur content in sulfur cored wire.