Study on a compound fertilizer with K, Ca, Si, Mg, and S elements by calcing a mixture of FGD residue and potassic ore
脱硫灰与钾矿石复合生产钾钙硅镁硫肥料研究

The study significance, reaction principle, manufacturing process, environmental safety assessment and applying method about manufacturing a compound fertilizer with K, Ca, Si, Mg and S elements by calcing a mixture of FGD residue and potash ore were introduced and evaluated in this paper. Meanwhile, its application prospect was also revealed. The research results showed that this process is feasible on theory completely. The manufactured fertilizer using this process contained 10.34%~12.0% K2SO4, 19.06%~32.28% CaO in citric acid, 10.98%~14.46% SiO2 in citric acid, 1.46%~1.82% MgO in citric acid. The pH value in manufactured fertilizer decreased 9.60 from 10.65 in the crude FGD residue. The heavy metal concentrations in the fertilizer were far lower than that of control standards of pollutants in fly ash for agricultural use. There was not a SO2 and other harmful gasous pollutants generated in the manufacturing process. The manufacturing cost was below 350 yuan per ton. This fertilizer could enhance medium-mass elements content of K, Ca, Si, Mg and S in soil, and promote or meliorate crop yield or quality. It would also achieve an objective to change waste into valuable, promote recycled economics development.