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目前,水泥生料中氧化铁的测定,大都采用KMnO_4或K_2Cr_2O_7滴定法,虽具有准确、快速且易掌握的优点,但需使用有毒的HgCl_2,污染环境,有害人体健康。本文采用KI—Na_2S_2O_3法测定铁,用H_3PO_4溶解试样,在较强的盐酸酸度下和温热的试液中,加入KI将Fe~(3+)还原为Fe~(2+),而I~-本身被氧化,析出等当量的I_2,以Na_2S_2O_3标液滴定游离I_2。本方法不必使用有害的汞盐仍具有简便、快速、灵敏、准确的优点。分析方法:精确称取水泥生料0.5克.移入盛有少许水(约1—2毫升)的250毫升锥形瓶中.
At present, the determination of iron oxide in cement raw materials, mostly using KMnO_4 or K_2Cr_2O_7 titration method, although accurate, fast and easy to grasp the advantages, but the use of toxic HgCl_2, polluting the environment, harmful to human health. In this paper, iron was determined by KI-Na_2S_2O_3 method, and H_3PO_4 was used to dissolve the sample. Under strong hydrochloric acid and warm solution, KI was added to reduce Fe 3+ to Fe 2+. ~ - itself is oxidized, precipitation equivalent I_2, Na_2S_2O_3 standard titration free I_2. This method does not have to use harmful mercury salts is still simple, fast, sensitive and accurate advantages. Method of analysis: Accurately weigh 0.5g of cement raw material and move into a 250ml conical flask containing a little water (about 1-2ml).