科研之友
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摘要
Fertilizers ensure the necessary agricultural yields to feed an increasing world population. Augmenting fertilizer use conflicts with environmental concerns such as eutrophication and soil pollution, as well as with limited availability of fertilizers in the Global South. Currently, potassium fertilizers are soluble salts such as KCl, which are mined in the northern hemisphere. Two key issues arise for tropical agriculture. First, the inherent solubility of potassium salts questions their efficacy in weathered soils. Second, longdistance transportation leaves unsolved the problems of limited local supplies and infrastructure, freightrelated CO2 emissions and cost of the fertilizer for the end user. In this work, we synthesize according to green-chemistry principles a novel potassium-bearing material which mineralogy and elemental release have the potential to overcome the limitations of KCl. We process in mild hydrothermal conditions (T = 200 degrees C; P similar to 14 atm; t = 5 h) locally available K-feldspar ore (ultrapotassic syenite) and CaO. The resulting hydrothermal material is characterized using X-Ray Powder Diffraction (XRD), Electron Microscopy (EM), Electron Probe Micro-Analyzer (EPMA), Particle Size Distribution (PSD) and Specific Surface Area (SSA). Additionally, leaching tests are performed, showing that the availability of potassium in the processed material is two orders of magnitude higher than in the raw K-feldspar ore. This work introduces a greenchemistry paradigm for the synthesis of potassium fertilizers.
- 出版日期2017-11-7
- 单位MIT
