间接碘量法测定稀土硫化物中硫  

Determination of sulfur in rare earth sulfides by indirect iodometry

作　　者：张晓凡 许嘉智 张文达 郝茜[2] 

机构地区：[1]包头市宏博特科技有限责任公司,内蒙古包头014030 [2]包头稀土研究院,内蒙古包头014030

出　　处：《冶金分析》2016年第2期61-64,共4页Metallurgical Analysis

摘　　要：试验提出了一种用间接碘量法测定稀土硫化物中硫含量的方法：稀土硫化物易与盐酸反应生成硫化氢，而硫化氢气体易和碘反应，故用已知浓度和用量的碘标准溶液完全吸收硫化氢气体，再用已知浓度的硫代硫酸钠标准溶液滴定出未反应的碘标准溶液，从而间接计算出稀土硫化物中硫含量。通过溶剂的选择、碘标准溶液用量及反应摇动时间的研究，确定了适宜的反应条件。结果表明，在稀土硫化物中硫质量分数为1O％～25％时的最佳反应条件是：用盐酸作为反应溶剂，0．1mol／L碘标准溶液用量为35mL，反应开始至滴定前的剧烈摇动时间为2min。采用实验方法对稀土硫化物中具有代表性的Ce2S3、Sm2S3及La2S3这3种样品中的硫进行了测定，结果的相对标准偏差（RSD，n=11）小于1％。测定结果与高频红外吸收法及硫酸钡重量法的测定值基本相符。A determination method of sulfur content in rare earth sulfides by indirect iodometry was proposed.The rare earth sulfides reacted with hydrochloric acid to form hydrogen sulfide,which could then react with iodine.The generated hydrogen sulfide gas was fully absorbed by iodine standard solution with known concentration and dosage.Then,the content of sulfur in rare earth sulfides could be indirectly calculated.The proper reaction conditions were obtained by the selection of solvents,the dosage of iodine standard solution and the shaking time of reaction.The results indicated that the optimal reaction conditions for the determination of 10%-25%(mass fraction)sulfur in rare earth sulfides were listed as follows:the hydrochloric acid was used as reaction reagent;the dosage of 0.1mol/L iodine standard solution was35mL;the vigorous shaking time from reaction starting to titration was 2min.The proposed method was applied to the determination of sulfur in three representative rare earth sulfide samples(Ce_2S_3,Sm_2S_3 and La_2S_3).The relative standard deviations(RSD,n=11)were less than 1%.The found results were consistent with those obtained by high frequency infrared absorption method and barium sulfate gravimetric method.

关 键 词：稀土硫化物 硫 间接碘量法 

分 类 号：TQ133.3[化学工程—无机化工] O655.2[理学—分析化学]