采用分光光度法,分别以偶氮胂Ⅲ、偶氮氯膦Ⅲ作为显色剂测定含稀土磷矿石中稀土元素总量。结果表明,偶氮氯膦Ⅲ显色剂要优于偶氮胂Ⅲ,它具有较宽的酸度适应范围和较强的抗杂质干扰能力。稀土的浓度在0μg/mL~50μg/mL范围内符合比尔定律,标准加入回收率试验显示该方法准确可靠。 The total rare earth elements in rare earth phosphate rock were determined by spectrophotometry with arsenazo Ⅲ and chlorophosphonazo Ⅲ as chromogenic reagent. The results show that chlorophosphonazo Ⅲ color reagent is superior to arsenazo Ⅲ, which has a wide range of acidity adaptation and strong resistance to impurities. Beer’s law is obeyed in the range of 0μg / mL ~ 50μg / mL. The standard addition recovery test shows that the method is accurate and reliable.