天然沸石作为离子交换肥料的研究——Ⅱ斜发沸石对磷矿石的溶解及对土壤有效磷的影响

Studies on using natural zeolites as ion exchanging fertilizers——Ⅱ. The effects of clinoptilolite on the dissolution of phosphate rocks and on the content of soil available phosphorus.

在实验室条件下,研究了斜发沸石(Cp)对三种不同磷矿石的溶解作用及对土壤有效磷的影响。结果表明:斜发沸石上所吸附的阳离子在不同程度上都有增加磷矿石的水溶性磷的作用,其增溶量因矿石种类而异。而且不同斜发沸石还因其所吸附的阳离子种类不同,对水溶性磷的增溶效果也有极大差别。各种吸附离子对水溶性磷的增溶效果依次为:H.Al-Cp>Na-Cp>NH_4-Cp>K-Cp>Ncp>Mg-Cp>Ba-Cp>Ca-Cp.但就磷矿石中酸性枸溶性磷的溶解能力而言,同样用斜发沸石处理,其对所试三种磷矿石种类影响均不大。这些事实说明斜发沸石对磷矿石中磷的增效机制,主要是通过斜发沸石上的吸附性阳离子和磷矿石中Ca^(2+)离子的直接接触交换或溶液交换的结果。另一方面,也可以根据不同吸附离子对Ca^(2+)离子的选择交换力大小的序列而加以解释。此外磷矿石本身的化学组成及结晶构造等特征不同,也是产生上述磷的增溶效果不等的原因。中性或微酸性水稻土施用斜发沸石能增加土壤有效磷含量(Bray-Ⅰ磷),并使其固磷能力有所下降。而酸性较强的土壤则因有次生固磷作用,有效磷含量没有增加。

The jinyun zeolite ore in Zhejiang Province is one of the largest zeolite deposits in China. It mainly consists of clinoptilolite ( Cp ) and mordenite ( Mdn ) . The predominant exchangeable cations on the two zeolites are Ca2+ and Na+ , along with small amounts of K2+ and Mg2+ . The selectivity sequence of Ca2 + for the adsorbed cations in the specially prepared clinoptilolite is:Na-Cp> NH4-Cp>K-Cp>Mg-Cp>Ba-Cp. The competitive adsorption equilibrium between K+and Ca2+on Na-Cp is described fairly well using Gapon equation, The Gapon coefficient in this case is about 14 for the K+-Ca2+ exchange, which shows that the clinoptilolite exhibits unusually high preference for K+ ion adsorption.