Physio-Chemical Preparation of Slow-Release Potassium Fertilizers


Background: In this work, one of the novel types of slow-release fertilizers (SRF) consisting of kaolin as clay material and K2SO4 was synthesized through a mechanochemical process by grinding in a ball mill planetary model. Methodology: The test samples of different weight % from 25 to 75 of kaolin contents were milled for 2 h at fixed milling speeds of about 600 rpm to assess the integration of K2SO4 and to measure the liberation of K+ and SO42- ions into solution. The properties of the studied samples were characterized by Fourier transformation infrared spectrometry (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and ion chromatography (IC). Incorporating K2SO4 into an amorphous kaolin structure using mechanochemistry is a green chemistry method that has been successfully applied. K+ content was measured in deionized water solution and the soil column leaching test was performed to determine the slow-release performance of the material. Results: The optimum released amount of K+ after 24 h was for (1:1 wt ratio) kaolin -K2SO4 samples that were 123.9 ppm at milling conditions at 600 rpm milling speed for 2 h.Conclusion: Indicating that K2SO4 – kaolin milled samples has good slow-release properties under specific conditions. In addition to being cost-effective and eco-environmentally, with prepared SRF, we can significantly increase the efficiency of fertilizer utilization in green agriculture.