Hydrothermal Synthesis Of Merlinoite From Sanidine-glauconitite Powder:An Experimental Study

In view of the uneven distribution of global potassium resources and the fact that the world’s potash producers are mainly Russia,China,Canada,Belarus,Germany,Israel and Jordan,the production of which is about 90%of the world’s total production,,therefore,the supply of potash fertilizer in international trade is very tight,and many countries rely on the international market for the supply of potash fertilizer.If we can make use of insoluble potassium resources,such as potassium feldspar,nepheline,Muscovite,glauconite,etc.we can effectively alleviate the serious shortage of water-soluble potassium resources,and the rational utilization of resources can be achieved.The glauconite powder used in this paper is obtained by crushing and grinding the Brazilian glauconite ore.The main chemical composition analysis results were K₂O11.55%、Mg O 3.23%、Fe₂O₃ 7.03%、Al₂O₃ 15.85%、Si O₂ 58.60%.The main mineral compositions were:glauconite mass fraction was 61.03%,sanidine was 31.5%,quartz was 3.47%,Muscovite was 3.25%,and magnesite was 0.85%.The materials needed for hydrothermal reaction were prepared from glaucomite powder and pure potassium carbonate,and the effects of alkali ore ratio,sintering temperature and time on sintering reaction results were investigated experimentally.Through the experiment concluded that When the content of potassium carbonate is low,the reaction cannot proceed completely,and the products are mainly leucite and KAl Si O₄.The increase of alkali ore ratio is conducive to the reaction,and the final product of the reaction is KAl Si O₄.The improvement of sintering temperature and the extension of sintering time were beneficial to the sintering reaction of glaucomite powder.Finally,it was concluded that the optimized technological conditions of sintering reaction were as follows:alkali ore ratio was 0.45,sintering temperature was950℃,sintering time was 1.5h.Calculated by OLI Systems phase equilibrium simulation,The reaction conditions of hydrothermal synthesis of merlinoite can be completely reacted in the range of KOH concentration was 0-1mol/kg,temperature was 150-240℃and liquid-solid ratio was5-30,Based on this,the experimental conditions were designed to explore the actual optimal process conditions for the hydrothermal synthesis of merlinoite from sintered materials.Hydrothermal synthesis experiments were carried out on the materials obtained through sintering reaction,The effects of KOH concentration,liquid-solid ratio,reaction temperature and reaction time on the hydrothermal synthesis of merlinoite from the sintered products of glauconite powder were investigated.The results show that the optimal process conditions of hydrothermal synthesis of merlinoite are:KOH concentration was 0.2mol/kg,liquid-solid ratio was 5,the reaction temperature and reaction time were 210℃and 8h,the merlinoite was mainly produced at the time of 2-8h at 210℃.Compared with the traditional chemical reagent to synthesize merlinoite,the hydrothermal synthesis of merlinoite by glauconite powder can not only effectively use the insoluble potassium resources,but also greatly shorten the synthesis time of merlinoite,it saves the cost and has good application value.