低分子量有机酸对含钾矿物钾素释放及其动力学模型的影响

Effects of low-molecular-weight organic acids on potassium release from different K-bearing minerals using kinetic models

采用连续流动浸提的方法,研究了酒石酸和草酸对不同含钾矿物(黑云母、白云母和微斜长石)钾释放及动力学模型的影响。结果表明:酒石酸连续流动浸提条件下,黑云母、白云母和微斜长石的释钾量分别是对照处理(去离子水)各矿物释钾量的2.2、3.3和2.6倍;草酸浸提条件下,黑云母、白云母和微斜长石的释钾量分别是对照处理的2.7、4.5和10.1倍;不同溶液连续流动浸提条件下,各矿物的释钾量均表现为黑云母﹥白云母﹥微斜长石;分别采用抛物线扩散模型、双常数模型、Elovich模型和一级动力学模型对不同矿物中钾的释放量进行方程拟合,结果表明,4种模型模拟条件下黑云母、白云母的钾释放动力学方程均达到了极显著的水平,决定系数R2介于0.591~0.999;一级动力学模型模拟下微斜长石钾释放的动力学方程达到了极显著水平。连续流动条件下,低分子量有机酸可显著提高不同含钾矿物的钾素释放量。

Effects of low-molecular-weight organic acids（tartaric acid and oxalic acid） on potassium（K） release from different K-bearing minerals（biotite,muscovite,and microcline） were studied with the continuous flowing method to explore an optimal model for describing K＋release kinetics and provide theoretical evidence to further evaluate plant available K of soil.Results showed that the amounts of K release from biotite,muscovite and microcline extracted by tartaric acid were 2.2,3.3 and 2.6 times as high as that by water,respectively,while the amounts of K release extracted by oxalic acid were 2.7,4.5 and 10.1 times as high as that by water,respectively.The amount of K release from K-bearing minerals with different extractions in continuous flow method was in order of biotite 〉muscovite 〉microcline.Parabolic diffusion,power function,Elovich equation and first order equation were used to describe the release of K from Kbearing minerals,and the result shows that the determination coefficients（R^2） of the kinetic equations were from 0.591 to 0.999,showing significant correlations for biotite and muscovite.The effect of low-molecular-weight organic acids on microcline K release kinetics under the first order equation reached extremely significant level.Under the condition of continuous flow,lowmolecular-weight organic acids can significantly improve K release in different K-bearing minerals.