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铁的价态分析,一般是在惰性气氛保护下,借助于硫氰酸盐作指示剂的一价汞的目视汞量法测定在Fe(Ⅱ)存在时的Fe(Ⅲ);然后在另一份试液中,以二苯胺磺酸钠或o,o＇一二氮杂菲为指示剂,用K_2Cr_2O_7滴定以测定Fe(Ⅱ)。也可用K_2Cr_2O_7法测定试样中的Fe(Ⅲ)和Fe(Ⅱ)合量后,另一份试液在惰性气氛保护下,加入硫磷混酸及二苯胺磺酸钠,以K_2Cr_2O_7滴定Fe(Ⅱ);再用差减法求得Fe(Ⅲ)的含量。二法虽简便快速,准确度高,但都应用了污染环境的汞盐和铬盐;同时钒、砷、锑、钼、锰、铬等变价元素有干扰。为此,我们对文献介绍在磷酸介质中,以硫脲消除Cu(Ⅱ)、Mn(Ⅶ)、Cr(Ⅵ)、V(Ⅴ)、As(Ⅴ)、Sb(Ⅴ)及Ti(Ⅳ)等的影响,用TiCl_3滴定矿石中Fe(Ⅲ)的方法进行了研究。提出
The analysis of the valence of iron is generally based on the visual mercury measurement of mercury by means of thiocyanate as an indicator for the determination of Fe (III) in the presence of Fe (II) under inert atmosphere protection. A test solution, sodium diphenylamine sulfonate or o, o ’a phenanthroline as an indicator, titration with K_2Cr_2O_7 to determine Fe (Ⅱ). K_2Cr_2O_7 method can also be used to determine the amount of Fe (Ⅲ) and Fe (Ⅱ) in the sample after the other test solution under inert atmosphere, the addition of phosphoric acid and sodium diphenylamine sulfonate K_Cr_2O_7 titration of Fe (Ⅱ ); Then the subtractive method was used to determine the content of Fe (Ⅲ). Although the second method is simple, rapid and accurate, both mercury salts and chromium salts that pollute the environment have been applied. At the same time, the price-changing elements such as vanadium, arsenic, antimony, molybdenum, manganese and chromium interfere. For this reason, we introduced the literature on the elimination of Cu (Ⅱ), Mn (Ⅶ), Cr (Ⅵ), V (Ⅴ), As (Ⅴ), Sb (Ⅴ) and Ti (Ⅳ) And other effects, TiCl_3 ore titration Fe (Ⅲ) method was studied. put forward