金基合金中钯的络合滴定

COMPLEXOMETRIC TITRATION OF PALLADIUM IN GOLD ALLOYS

在盐酸介质中以磷酸三丁酯—三氯甲烷萃除金(Ⅲ)、铁(Ⅲ)。萃取剂事先用钯(Ⅱ)饱和防止钯的损失。用抗坏血酸消除残存金(Ⅲ)的干扰。用硫脲从“pd—EDTA”络合物中释放出“EDTA”,以铅(Ⅱ)滴定。共存的Pt(Ⅳ)、Cu(Ⅱ)、Zn(Ⅱ)、Fe(Ⅲ)、Al(Ⅲ)等不干扰钯的测定。此方法用于多元金基合金中钯的测定,简便、准确、容易掌握。钯含量10％～40％时,标准偏差0.03～0.13,极差0.09％～0.32％。

Gold (Ⅲ)、iron (Ⅲ)are extracted and separated with tributylphosphonate ester (TBP)-trichloromethane in aqueous chlorhydric acid. Extractive solvent is first saturated with palladium (Ⅱ) preventing palladium from losing. Interference of remnant gold(Ⅲ) is eliminated with vitamin C. After being set free 'EDTA' from 'Pd-EDTA' complex compound by using thiourea,The 'EDTA' is titrated with nitric lead(Ⅱ). The coexistent Pt(Ⅳ),Cu(Ⅱ),Zn(Ⅱ),Fe(Ⅲ),Al(Ⅲ) etc. Don't interfere in determination of palladium. The method has been applied to determine palladium in many-part gold alloy,which is simple,accurate and easy to operate. When the content of palladium is 10％～40％,the standard deviation is 0.03％～0.13％ and the maximum deviation is 0.09％～0.32％.