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本文对磷的酸碱容量法作了改进,提出用中性子醛溶液处理磷钼酸铵沉淀后,用含适量可溶性钙盐的硝酸标准溶液回滴过量的氨氧化钠,按磷的当量值为其原子量的1/27计算磷的含量。这样处理的结果,可克服原有分析方法所存在的硝酸滴定NH_3·H_2O时用酚酞作指示剂带来的终点误差;氨在碱性介质中因挥发而造成的损失以及PO_4~(3-)与H~+反应速度较慢等缺点,使这种测定磷的标准分析方法更趋完善,测定的结果更为准确可靠。
In this paper, the acid-base capacity of phosphorus was improved. It is proposed that after neutralizing the precipitate of ammonium phosphomolybdate with a solution of neutral aldehyde, the excessive amount of sodium nitrite is dropped back with a standard solution of nitric acid containing a suitable amount of soluble calcium salt, The atomic weight of 1/27 calculated phosphorus content. The result of this treatment can overcome the endpoint error caused by the phenolphthalein as indicator in the nitric acid titration NH 3 · H 2 O existing in the original analysis method; the loss due to volatilization of ammonia in alkaline medium and the concentration of PO 4 3- And H ~ + slow reaction and other shortcomings, so that the determination of phosphorus standard analytical methods more perfect, the determination of the results more accurate and reliable.