对偶氮氯膦Ⅲ和钍、铀在磷酸体系中的显色行为作了研究,提出以TRPO-G.D.X-301萃取色层分离稀土、钛、锆等干扰元素、用双波长分光度法同时测定铀矿石中钍和铀的方法。测定钍和铀时,测量波长、参比波长分别为690nm、608nm和670nm、707nm,工作曲线在0～50μg/25ml内成线性。测定矿石中0.03%～0.5%的钍和铀时,误差小于10%。本法可用于复杂样品中钍和铀的同时测定。 The chromogenic behaviors of chlorophosphonazo Ⅲ, thorium and uranium in phosphoric acid system were studied. The interference elements such as rare earth, titanium and zirconium were separated by extraction with TRPO-GDX-301, and the simultaneous determination of uranium by dual wavelength spectrophotometry Methods for thorium and uranium in ores. Measurement thorium and uranium, the measurement wavelength, the reference wavelength were 690nm, 608nm and 670nm, 707nm, the working curve in 0 ~ 50μg / 25ml within a linear. The determination of 0.03% to 0.5% of thorium and uranium ore, the error is less than 10%. This method can be used for the simultaneous determination of thorium and uranium in complex samples.