活化钾矿的钾释放动力学研究

    Kinetics of potassium release of activated insoluble potassium ores

    • 摘要:
      目的  建立活化钾矿的钾释放动力学模型.
      方法  采用活化剂对非水溶性钾矿(钾长石、富钾页岩)进行活化, 通过阳离子盐溶液(NH4+、Na+)连续振荡浸提, 分析阳离子盐溶液对活化钾矿动态释钾过程的影响, 研究活化钾矿的钾释放动力学模型.
      结果和结论 各浸提剂浸提钾矿的释放曲线均表现出前期快速, 之后缓慢释放的变化趋势.浸提剂浸提钾长石、活化钾长石钾的初始释放量顺序为:NH4Cl>NaCl>H2O, 累积释放量顺序为:NaCl>NH4Cl≈H2O; 富钾页岩、活化页岩的整个动态释钾过程均表现为:H2O>NaCl>NH4Cl.分别用双常数模型、一级动力学模型、扩散模型和Elovich模型对钾矿及其活化钾矿累积释钾量进行拟合, 钾长石、活化钾长石的最优动力学模型是Elovich模型或双常数模型; 富钾页岩、活化页岩的最优动力学模型是Elovich模型.钾长石、活化钾长石的一级动力学模型在2种浸提剂NH4Cl和NaCl间的拟合性无明显差异; NH4Cl浸提的动力学模型拟合性均优于NaCl.活化钾矿的钾初始释放速率、平均释放速率以及最大平衡释放量均有显著提高.初始释放速率的增大是活化钾矿的钾最大平衡释放量增多的主要原因.

       

      Abstract:
      Objective To establish the kinetics model of potassium(K) release of activated insoluble potassium ores and provide the scientific evidence for reasonable evaluation and highly efficient utilization of activated insoluble potassium ores.
      Method The insoluble potassium ores (potash feldspar、K-shale) were activated by the activator which was successively extracted through cation solution(NH4+, Na+) to study the effects of cation solution on K dynamic release of activated potassium ores and the kinetic model of K release.
      Result and conclusion  The results showed that there were two stages of the K release of activated potassium ores including quick release at the initial stage and slow release at the final stage. The capability of different extraction solution to release initial K from potash feldspar and activated forms was in order of NH4Cl > NaCl > H2O, while the K accumulative release amount was in order of NaCl > NH4Cl≈H2O.The total K release amount of K-shale and activated K-shale was in order of H2O > NaCl > NH4Cl.The first order equation, power function, parabolic diffusion equation and Elovich equation were used to describe the K release of insoluble potassium ores.The Elovich equation or power function was the best model to describe the K release of potash feldspar and activated potash feldspar, and the Elovich equation was the best model for K-shale and activated K-shale.The K release models with successive extraction of NH4Cl were better than those of NaCl.However, the effects of two extraction solu-tions had no significant difference when using the first order equation to describe the K release of activated potash feldspar.The initial release rate, mean release rate and maximum balanced release amount of K from activated potassium ores increased significantly.The increase of initial release rate was the main reason of the increase of the maximum balanced release amount.

       

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