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一、硅和铁的快速比色测定: 试样用稀硫酸溶解。(采用硅钼兰比色法测定硅的含量;用盐酸羟胺将铁还原为两价,控制pH为5,用邻菲罗啉作显色剂测定铁的含量)。大量三价铬的存在,通过选择适当的滤光片和在曲线上加以校正的方法消除对硅和铁的影响。分析步骤如下:取0.2克试样,加50毫升(1:9)硫酸溶液,低温加热溶解,冷却后移入200毫升容量瓶中,用水稀释,摇匀。取10毫升试液,准确加20毫升水,5毫升5%钼酸铵溶液,在水浴加热至70℃,冷却,加10毫升硫酸—草酸混合溶液(100毫升中含有2毫升硫酸,3克草酸),5
First, the rapid colorimetric determination of silicon and iron: The sample was dissolved with dilute sulfuric acid. (Silicon molybdenum blue colorimetric determination of silicon content; hydroxylamine hydrochloride with iron reduced to two, the control pH is 5, with phenanthroline as a reagent for the determination of iron content). The presence of a large amount of trivalent chromium eliminates the effects on silicon and iron by selecting the appropriate filters and correcting them on the curve. Analysis steps are as follows: Take 0.2 g sample, add 50 ml (1: 9) sulfuric acid solution, low temperature heating dissolved, cooled and transferred to 200 ml volumetric flask, diluted with water, shake. Take 10 ml of test solution, add exactly 20 ml of water and 5 ml of 5% ammonium molybdate solution, heat to 70 ° C. in a water bath, cool and add 10 ml of sulfuric acid-oxalic acid mixed solution (100 ml containing 2 ml of sulfuric acid and 3 g of oxalic acid ), 5