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

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.