含稀土磷矿酸解动力学及稀土浸出机理

Acidolysis kinetics and RE leaching mechanisms of RE-bearing phosphorite ores

  • 摘要: 对织金新华含稀土磷矿酸解过程动力学及稀土浸出机理进行了研究.结果表明:∑REO转化率动力学曲线与P2O5转化率动力学曲线变化趋势相近,即随着温度和溶液酸度的升高,稀土的转化率提高;∑REO的酸解动力学可用德罗兹多夫方程来很好的描述,拟合曲线的相关系数在0.99以上.根据Arrhenius方程对磷矿酸解过程P2O5的反应表观活化能计算表明,织金新华磷矿酸解的主要反应为固态膜扩散控制过程,而稀土在磷矿中的类质同象存在形态也决定了其反应属于固态膜扩散控制过程.织金新华磷矿酸解过程稀土的浸出机理分析表明,稀土主要以RE2(SO4)3形式存在于溶液中,而磷石膏中的稀土以RE2(SO4)3和硫酸钙晶体包裹的形式存在.

     

    Abstract: The kinetics behaviors and leaching mechanisms of rare earths by acidolysis were studied for Zhijin Xinhua phosphorite ores. It is shown that the ∑REO conversion ratio increases with increasing temperature and sulfuric acid concentration in the reacting solution, which is similar to the kinetics process of P2O5. The acidolysis kinetics of ∑REO reveals that the Drozdov equation can describe the dissolution progress of the ores quite well. The correlation coefficient fitting experimental data is more than 0. 99. The reaction apparent activation energy of P2O5 calculated by the Arrhenius equation indicates that the main reaction of Zhijin Xinhua phosphorire ores dissolved by sulfuric acid is a solid-film diffusion control process, as well as for ∑ REO because of its special presentation in the form of ions in the lattices of collophanite. In addition, studies on the leaching mechanisms of ∑REO dissolved by sulfuric acid show that RE2(SO4)3 is the main existence state in the solution, while RE2(SO4)3 and rare earths enwrapped by calcium sulphate crystals are the main existence state in phosphogypsum.

     

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