采用固氟氯化法从氟碳铈矿中提取稀土氯化动力学的研究进展

Kinetics of Chlorinating Rare Earth in Bastnaesite with NH_4Cl Chlorinating Method after Fixed Fluorine Treatment

针对我国主要的稀土矿物氟碳铈稀土矿目前在分解回收中主要采用浓硫酸焙烧法产生氟化氢污染环境的问题,清华大学核能与新能源研究院从1998年以来开展了氧化镁固氟、氯化铵选择性氯化提取氟碳铈中稀土及其动力学的研究。选择我国典型的稀土矿物包头混合型稀土矿及山东氟碳铈稀土矿展开研究,确定了适宜的工艺条件、氯化选择性和氟的转化形态。稀土以氯化稀土形式被浸取,对于两种稀土矿物稀土浸出回收率均在85%以上。氯化铵氯化稀土的氯化动力学符合Bagdasarym提出的多相区域反应动力学模型,氯化反应的速率αRE遵从Erofeev方程。氯化铵氯化不同形态氧化稀土氯化反应表观活化能的大小顺序为:EaLa2O3+CeO2<Ea包头矿<EaLa2O3<EaREO<Ea微山矿<EaCeO2。固氟焙砂的化学组成、微粒结构、微粒粒径、比表面、组分间作用、稀土元素的配分是影响固氟氯化铵焙烧分解法提取不同稀土矿物中稀土工艺和氯化反应速率常数的重要因素。CeO2的氯化是混合氧化稀土氯化的控速步骤;CeO2与NH4Cl反应生成氯氧化物是决定混合氧化稀土氯化率的关键。

In has decomposed in the collection under in view of our country main rare earth mineral is hamartite mainly to use the strong sulfuric acid method of roasting produces the hydrogen fluoride pollution environment the question at present. Tsinghua University nuclear power and the new energy research institute since 1998 develops the magnesia fixed fluorine, the ammonium chloride selectivity chlorination has withdrawn in the hamartite and its dynamics research. Has chosen the our country model rare earth mineral Baotou mixed type thin native ores and the Shandong hamartite thin native ores launches the research, had determined the best craft condition, the chlorination process to the iron, the silicon aluminum has the selectivity, at the same time in the rare earth mineral the fluorine mainly by the magnesium fluoride, the calcium fluoride keeps in the leaching dregs, the rare earth by chlorinates the rare earth form to enter soaks takes the fluid, regarding two kind of rare earth minerals rare earth leaching returns - ratio 〉 85%. the chlorination of rare earth for fixed fluorine calcine accords with the regional reaction rate model which is raised by Bngdasarym and it has experienced two steps in series. The equation of reaction rate obeys Erofeev Equation. The apparent activation energy of file ammenium chloride chlorination different condition oxidation rare earth size order is： EaLa2O3＋CeO2〈EaBaotou ore〈EaLa2O3〈EaREO〈Eaweishai ore〈EaCeO2. The fixed fluorine bakes the granulated substance the chemical composition, the particle structure, the particle size, the relative surface, various components affects, the rare earth element partition is mutually affects the solid fluorine ammonium chloride masting resolution to withdraw in the different rare earth mineral the rare earth craft condition and the eldorination constant of action important attribute. The cldorination is mixes the oxidized rare earth chlorination to control the fast step. CeO2 and the NH4Cl response production oxychloride decides the mix oxidation rare earth chlorination rate key.