四氯化碳浸取-碘量法测定二硫化钨中游离硫

Carbon tetrachloride extraction-iodimetry determination of free sulfur in tungsten disulfide

在自制的冷凝回流浸取装置中,用四氯化碳浸取试样中的游离硫,过滤后将滤液浓缩至石英舟中,于1 000℃管式炉中通氧气燃烧,生成的二氧化硫,以淀粉吸收液吸收,用碘量法测定。对CCl4浸取游离硫的条件进行研究,结果表明,浸取温度、CCl4的用量、浸取时间、称样量（硫量）以及在浸取过程中溶液的搅拌程度对测定结果都有影响。实验选用在60 mLCCl4中加入1-5 g试样,于80℃恒温水浴上加热回流15-20 min的条件下进行浸取。方法用于二硫化钨中游离硫质量分数为0.65%-2.42%的样品测定,相对标准偏差在1.3%-2.7%之间。

Free sulfur in WS2 sample was extracted by CCl4 in a self-made condensate reflux extraction plant.The filtrate was concentrated into a quartz-boat,and then combusted in a tube-stove at 1 000 ℃by filling oxygen.The produced sulfur dioxide was absorbed with starch solution and then determined by iodimetry.The extraction conditions of free sulfur by CCl4 were studied.The results indicated that the extraction temperature,dosage of CCl4,extraction time,sampling amount（sulfur content） and the stirring of solution had all influence on the determination.In this study,1-5 g of sample was added into 60 mL of CCl4,and then extracted at 80 ℃ in thermostat water bath under refluxing for 15-20 min.This method was applied to the determination of tungsten disulfide sample containing 0.65 %-2.42 %（mass fraction） free sulfur.The relative standard deviations were in the range of 1.3 %-2.7 %.