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磷铜合金中磷的间接络合滴定法测定,常用的有磷酸铵镁沉淀法及磷酸铋沉淀法。我们采用镧(Ⅲ)作沉淀剂,LaPO_4溶度积小(3.7×10~(-23)),沉淀生成迅速,可不经分离直接进行磷的测定。分析方法试样中的磷经氧化成PO_4~(3-)后,在pH5.5左右,加入过量La-EDTA溶液,再以标准锌溶液进行滴定。
Phosphorus-copper alloy indirect phosphorus complexometric titration, commonly used ammonium magnesium phosphate precipitation and bismuth phosphate precipitation method. We use lanthanum (Ⅲ) as precipitating agent, LaPO_4 has a small solubility product (3.7 × 10 ~ (-23)), the precipitate is formed quickly and can be directly measured without separation. Analysis Method After the phosphorus in the sample is oxidized to PO_4 ~ (3-), at pH5.5, excess La-EDTA solution is added and titrated with standard zinc solution.