Abstract The article presents the results of studies of the process of obtaining NPK fertilizer from low-grade phosphate raw materials with P2O5 of about 18%. Phosphate raw materials were leached with a mixture of nitric-phosphoric acids with the addition of potassium carbonate, which serves as a source of potassium in the final product. The main parameters determined were the content of the main nutrients P2O5:N:K2O, temperature and time of the leaching process. According to the graphical method, the “apparent” activation energy of the heterogeneous process is found, which is equal to 3.8 kJ/mol indicates the intradiffusion nature of the process. Methods of chemical analysis, scanning electron microscopy and XRD analysis were used for a comprehensive study of raw materials and final products.

中文翻译：

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低品位磷酸盐原料合成氮磷钾肥

摘要 本文介绍了以P2O5为18%左右的低品位磷酸盐原料制取氮磷钾肥工艺研究成果。磷酸盐原料用硝酸-磷酸混合物浸出，并添加碳酸钾，碳酸钾是最终产品中钾的来源。确定的主要参数是主要养分P2O5:N:K2O的含量、浸出过程的温度和时间。根据图解法，发现非均相过程的“表观”活化能，等于 3.8 kJ/mol，表明该过程的内扩散性质。化学分析、扫描电子显微镜和 XRD 分析方法用于对原材料和最终产品进行综合研究。