| With the rapid development of phosphorous chemical industry, the governance and comprehensive utilization of phosphogypsum is more and more serious. Phosphogypsum is a kind of important renewable resources, at the same time, sulfur resource recycling is also the fouse of reusing phosphogypsum. Presently, the recycling of phosphogypsum has become a hot research project; There are few mineral deposits of water soluble potash ores in our country, potash seriously restricts the development of agriculture. However, potassium feldspar reserves are plentiful as a hard dissoluble mineral of kalium in china, how to integrate potassium feldspar to prepare potash, has always been a research hotspot. In the background, the issue put forward the academic ideas that using phosphogypsum and potassium to prepare raw gas of sulfuric and potassium sulfate. The way has great economic value and social significance, not only solved the environment pollution of phosphogypsum but also relieved shortage of potash fertilizer.This text with phosphorus gypsum and potassium feldspar as the main raw material, through grinding, metering and mixing, then roast under a high temperature to prepare soluble potassium and SO2. K2O dissolution rate and conversion rate are taken as indicators to analyze the influence of various factors on the reaction system, and the high temperature roasting process and reaction mechanism of the reaction system has carried on the preliminary discussion.(1) To ascertain the mechanism of the reactions of KAlSi3O8-CaO system and KAlSi3O8-CaSO4system, carried out a series of experimental studies.Roasting experiments results show that:potash feldspar can react with CaO and CaSO4separate, but its reaction mechanism is not the same, the mechanism of KAlSi3O8-CaO system is likely to be adsorption reaction mechanism, and the mechanism of KAlSi3O8-CaSO4system could be ion exchange mechanism. Dynamic analysis results show that: the decomposition reaction process of both conform to the G-B reaction kinetics model and belong to the solid-phase diffusion-controlled process.(2) Experimental factors such as atmosphere, temperature and time on the influence of the reaction system has been studied, The results showed that reducing the volume fraction of CO, raising roasting temperature and extending roasting time are favourable to raise the roasting degree. It determined the optimum parameters about reaction system, through single factor experiment research and orthogonal experiment research. The optimal parameters for:PCO/PCO2=0.1～0.2, roasting temperature is1200℃, roasting time is60min.(3) Under optimal process conditions the K2O dissolution rate is72%and the desulfurization rate is77%, By analyzing the XRD diffraction diagram of the solid-phase product, it discovered the main phase is K2SO4, K2Ca2(SO4)3, C2AS, KAS2, CS, C2S.(4) By analyzing the XRD diffraction diagrams of products on different roasting conditions, combined with change rule of potassium feldspar structure under high temperature and the ternary system phase diagram, roasting reaction mechanism for testing system of potassium feldspar-phosphogypsum was deduced, which laid a theoretical foundation to take potash from K-feldspar by high-temperature calcined.(5) To enhance the K2O dissolution rate, the effect of different plus on the reaction is investigated, and defined Na2SO4as the best assistant additives. When adding amount of Na2SO4is3%, roasting temperature is1200℃, the K2O dissolution rate can be up to87.39%. |
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