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铬铁中铬的测定,一般采用硫酸分解试样,在硫酸或硫-磷酸的介质中利用硝酸银作催化剂,以过硫酸铵将铬氧化至高价,又采用亚硝酸钠或氯化钠还原高价锰以消除锰的干扰。但用亚硝酸钠还原锰时,因铬铁中铬的含量较高(50％以上),即使在尿素存在的条件下,也很难保证铬不被还原;若用氯化钠或盐酸来消除高价锰的干扰,则所费时间太长。因此我们对铬铁中铬的测定作了改进,采用盐酸分解铬铁试样,以加快溶样速度,然后用硫-磷混合酸赶除盐酸,在一定比例的硫磷混合酸中,用高锰酸钾氧化铬至高价,继用氯化
Determination of chromium in ferrochromium, the general decomposition of sulfuric acid samples, the use of silver nitrate in the sulfuric acid or sulfur - phosphoric acid medium as a catalyst, ammonium persulfate oxidation of chromium to high prices, and the use of sodium nitrite or sodium chloride reduction of high Manganese to eliminate the interference of manganese. However, with sodium nitrite reduction of manganese, due to the high content of chromium in ferrochrome (50%), even in the presence of urea, it is difficult to ensure chromium is not reduced; if the use of sodium chloride or hydrochloric acid to eliminate High price of manganese interference, the time it takes too long. Therefore, we improved the determination of chromium in ferrochromium, using hydrochloric acid to decompose ferrochromium samples to speed up the sample-dissolving speed, and then remove the hydrochloric acid with sulfur-phosphorus mixed acid. In a certain proportion of mixed sulfuric acid and phosphoric acid, Potassium manganate chromium oxide to high prices, followed by chlorination