磷石膏基缓释氮肥的研究

Study on Phosphogypsum-based Slow Release Nitrogen Fertilizer

以磷石膏和氮肥为主要原料,制备磷石膏基缓释尿素和磷石膏基缓释碳铵。首先研究了磷石膏、黄壤和沙土3种介质对常规氮肥中氮素的缓控效果,然后制备出磷石膏基缓释氮肥,并与常规氮肥对比分析了磷石膏基缓释氮肥的养分释放特征,最后探讨了缓释机理。研究表明,黄壤对氮的控释较好,沙土其次,磷石膏较差;而磷石膏缓释氮肥养分释放缓慢,肥效周期长,具有良好的缓控作用;碳铵与磷石膏生成硫酸铵,增加了肥料的稳定性,尿素与磷石膏生成尿素石膏,降低了肥料的溶解性,膨润土、半水石膏和淀粉粘结剂用于造粒中,增加了颗粒的强度和胶凝性,从而赋予磷石膏基缓释氮肥优良的缓释性能。

Phosphogypsum-based slow release urea and phosphogypsum-based slow release ammonium bicarbonate were prepared from phosphogypsum and conventional nitrogen fertilizers（urea and ammonium bicarbonate） as the material.At first,the controlling effect of three materials phosphogypsum,yellow soil and sandy soil,on nitrogen release was researched.And then,phosphogypsum-based slow release nitrogen fertilizers were prepared and the nutrient release characteristic was analyzed compared with conventional nitrogen fertilizers.Lastly,the slow release mechanism was discussed.The result showed that the controlling effect of yellow soil on nitrogen release was better,sandy soil was second and phosphogypsum was poor.While phosphogypsum-based slow release nitrogen fertilizers had an excellent slow-release and long-term performance.Ammonium bicarbonate and phosphogypsum formed to ammonium sulfate to increase the stability of fertilizers;urea and phosphogypsum formed to urea-gypsum to decrease the solubility of fertilizers;The application of bentonite,hemihydrate phosphogypsum and starch adhesive increase the strength and gelling property of fertilizers.All of these gave the phosphogypsum-based slow release nitrogen fertilizers with excellent slow release property.