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磷钼酸和喹啉在强酸性介质中生成的磷钼酸喹啉沉淀,已广泛用于酸碱容量法测定磷.该法的特点是:沉淀的溶解度小,选择性好,灵敏度高,对于高含量磷的测定,精确度较高,但该法的缺点是:空白高,硅的干扰较严重,特别是硅高的时候,沉淀不易洗涤干净,整个流程需连续进行,方法较难掌握,分析结果系统偏高,不适用于微量磷的测定,也不适用于含硅高的矿石中磷的测定.本文介绍的磷钼酸喹啉氧化还原容量法是在硝酸盐酸混酸介质中使磷生成磷钼酸喹啉沉淀,在盐酸介质中,存在草酸及煮沸情况下用硫酸联胺将钼(Ⅵ)还原为钼(Ⅴ),
Phosphomolybdic acid and quinoline precipitation in strong acidic medium quinoline phosphomolybdic acid has been widely used in the determination of phosphorus acid capacity method.The method is characterized by: precipitation of small solubility, high selectivity, high sensitivity, for The determination of high content of phosphorus, high accuracy, but the law’s shortcomings are: blank high, more serious interference of silicon, especially when the silicon is high, the precipitate is not easy to clean, the entire process needs to be continuous, the method is more difficult to grasp, The analysis system is too high, not suitable for the determination of trace phosphorus, nor is it suitable for the determination of phosphorus in ores with high silicon content.In this paper, the quinoline phosphomolybdic acid oxidation-reduction capacity method is to produce phosphorus in nitric acid mixed acid medium Quinoline phosphomolybdic acid precipitation, in hydrochloric acid medium, the presence of oxalic acid and boil with molylamine sulfate molybdenum (Ⅵ) reduction to molybdenum (Ⅴ)