滴定硅酸盐岩石与土壤中氧化亚铁的对比研究  

Comparative study on titration of ferrous oxide in silicate rocks and soil

作　　者：曾江萍 王娜 王家松 吴磊 刘义博 ZENG Jiangping;WANG Na;WANG Jiasong;WU Lei;LIU Yibo(Tianjin Center,China Geological Survey(North China Center for Geoscience Innovation),Tianjin 300170,China)

机构地区：[1]中国地质调查局天津地质调查中心(华北地质科技创新中心),天津300170

出　　处：《华北地质》2024年第3期107-110,共4页North China Geology

基　　金：中国地质调查局项目:“地质调查标准化与标准制修订”(DD20190472)。

摘　　要：【研究目的】由于硅酸盐岩石与土壤的成分不同,开展硅酸盐岩石与土壤中氧化亚铁的对比研究有利于更加准确地滴定氧化亚铁的含量。【研究方法】本文对重铬酸钾滴定法滴定硅酸盐岩石与土壤中氧化亚铁进行了对比,重点比较了溶样时间对氧化亚铁的影响,实验使用硫酸(1+1)和氢氟酸溶样,多余的氟用硼酸络合,以二苯胺磺酸钠为指示剂,重铬酸钾标准溶液滴定氧化亚铁。【研究结果】分析结果表明,溶样时间对硅酸盐岩石和土壤中氧化亚铁影响较大,硅酸盐岩石和土壤样品分别在溶液完全沸腾0~2 min和8~10 min时滴定为宜;方法经国家一级标准物质分析验证,结果与参考值相符,硅酸盐岩石和土壤的精密度RSD(n=10)分别为1.94%、1.78%。【结论】因此,在实际操作中应根据样品的类型选择合适的溶样时间,能够更加准确地确定氧化亚铁的含量。This paper is the result of titration of ferrous oxide.[Objective]Due to the different compositions of silicate rocks and soil,conducting comparative studies on ferrous oxide in silicate rocks and soil is beneficial for more accurate titration of ferrous oxide.[Methods]This article compared the titration of ferrous oxide in silicate rocks and soil using potassium dichromate titration method,with a focus on the effect of sample dissolution time on ferrous oxide.The sample was dissolved with sulfuric acid(1+1)and hydrofluoric acid,the excess fluorine was complexed with boric acid,and ferrous oxide was titrated with sodium diphenylamine sulfonate as indicator and potassium dichromate standard solution.[Results]The results showed that the dissolution time had great influence on the ferrous oxide in rock and soil,and it was appropriate to titrate the rock and soil samples when the solution was completely boiled for 0~2 min and 8~10 min,respectively.The results were verified by the national standard material analysis,the results agreed with the reference values.The precision RSD(n=10)of rock and soil were 1.94%、1.78%respectively.[Conclusions]Therefore,in practical operation,the appropriate dissolution time should be selected according to the type of sample,in order to more accurately titrate the content of ferrous oxide.

关 键 词：氧化亚铁 硅酸盐岩石 土壤 溶样时间 

分 类 号：P585[天文地球—岩石学]