应用离子交换剂分解磷块岩的分析方法

氟是磷灰石的重要化学组成之一^1]。磷块岩和磷灰石中氟的测定,对磷灰石类型的鉴定和磷块岩的成因研究有重要意义。目前,氟的测定方法广泛地采用酸、碱溶(融)样,用蒸馏法进行元素分离^2,3,4]。近十几年来,由于离子选择电极法操作方便,被广泛地应用于各种类型物质中氟的测定^5]。离子交换剂可以用来分解某些难溶性的天然和合成材料,但是至今这个方法还未得到广泛地应用。

METHOD OF ANALYSIS OF PHOSPHARITE BY DISSOLUTION WITH ION-EXCHANGE REAGENT

Ion exchange resin ean dissociate some minerals of low solubility,but the method has not been widely used so far.Phosphate rocks are composed of compounds with Jow solubility.In suspension of compounds,chemical equilibrium between the solid phase and saturated solution may be established.The dynamic equilibrium depends on ion concentration of reaction products at specific temperature.When a hydrogenous 732 cation exchange resin exists in hot water,the resin adsorbs cations of the dissociated compounds,the anions of the dissociated compounds and the replaced H⁺ combinate into soluble compounds in form of ionic state.The process continues and establishes new equilibrium uninterruptedly till the minerals of low solubility are entirely dissociated.The author added 732 strong acid cation exchange resin into hot water and dissociated phosphate rocks successfully.The content of fluorine was determined by spectrophotometry quantitatively.In place of the traditional method of acid-alkali fusion and separation of coexisted ions by distillation,the ion exchange resin method here has avoided laborious operation in determination of fluorine.The author applied a magnetic stirring instead of the shaking method introduced by Schafer (1963) and a thermostatic water bath to control the solution temperature,which simplified the heating and temperature controlling procedure.The advantages of this method reported in this paper are simplicity of equipment,easiness of operation,good repeatability and efficiency.