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 amechanochemical process by grinding in a ball mill planetary model.Methodology: The test samples of different weight % from 25 to 75 of kaolin contentswere milled for 2 h at fixed milling speeds of about 600 rpm to assess the integrationof K2SO4 and to measure the liberation of K+and SO42-ions into solution. Theproperties of the studied samples were characterized by Fourier transformation infraredspectrometry (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA),and ion chromatography (IC). Incorporating K2SO4 into an amorphous kaolin structureusing mechanochemistry is a green chemistry method that has been successfullyapplied. K+content was measured in deionized water solution and the soil columnleaching 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 for2 h.Conclusion: Indicating th