The present study aims at the recovery of potassium from muscovite mica(which contains K_(2)O;~10 wt%)using NaCl-roasting coupled with H_(2)SO_(4)-leaching process.The preliminary acid leaching studies applying differ...The present study aims at the recovery of potassium from muscovite mica(which contains K_(2)O;~10 wt%)using NaCl-roasting coupled with H_(2)SO_(4)-leaching process.The preliminary acid leaching studies applying different mineral acids resulted in a potassium recovery of 8%−18%.The optimum leaching conditions for the maximum recovery were 4 mol/L H_(2)SO_(4),60 min leaching time and liquid-solid ratio 4 mL/g at 90℃.However,the roasting of muscovite with additive NaCl(muscovite:NaCl mass ratio of 1:1.00,900℃,45 min)followed by H_(2)SO_(4)-leaching(95℃,60 min)extracted potassium to the tune of 98%.Under similar roasting conditions,the H_(2)O-leaching process extracted only 60%of potassium.The effects of various roasting and leaching parameters such as temperature,time,NaCl concentration,acid concentration,liquid-solid ratio on potassium extraction were evaluated.The appearance of the sylvite(KCl)mineral phase in the NaCl-roasted muscovite and its disappearance in the acid/water leached residue confirmed the physical and chemical distortions of the muscovite crystal structure.The possible mechanism of potassium release from the complex muscovite structure was elucidated based on available literature substantiated by characterizations using X-ray diffraction(XRD)and scanning electron microscopy with energy dispersive X-rays spectroscopy(SEM-EDX).展开更多
The present paper reports the effective utilization of marble sludge powder(MSP)for the recovery of potash values from waste mica scrap using chlorination roasting-water leaching method.Characterization studies indica...The present paper reports the effective utilization of marble sludge powder(MSP)for the recovery of potash values from waste mica scrap using chlorination roasting-water leaching method.Characterization studies indicated the presence of dolomite as the major mineral phase in MSP,whereas muscovite and quartz were observed in the mica sample.The acid leaching studies suggest a maximum of 22%potash recovery under conditions:4 M H2SO4 acid,particle size of^100μm,stirring speed of 600 r/min,leaching temperature of 75℃,and leaching time of 90 min.The chlorination roasting-water leaching process was adopted to achieve the lowest level of 80%-90%potash recovery.The optimum conditions for the recovery of^93%potash from mica(~8.6wt%K2O)requires 900℃ roasting temperature,30 min roasting time,and 1:1:0.75 mass ratio of mica:MSP:NaCl.The roasting temperature and amount of NaCl are found to be the most important factors for the recovery process.The reaction mechanism suggests the formation of different mineral phases,including sylvite(KCl),wollastonite,kyanite,and enstatite,during roasting,which were confirmed by X-ray diffraction(XRD)analyses and scanning electron microscopy(SEM)morphologies.The MSP-blended NaCl additive is more effective for potash recovery compared with the other reported commercial roasting additives.展开更多
文摘The present study aims at the recovery of potassium from muscovite mica(which contains K_(2)O;~10 wt%)using NaCl-roasting coupled with H_(2)SO_(4)-leaching process.The preliminary acid leaching studies applying different mineral acids resulted in a potassium recovery of 8%−18%.The optimum leaching conditions for the maximum recovery were 4 mol/L H_(2)SO_(4),60 min leaching time and liquid-solid ratio 4 mL/g at 90℃.However,the roasting of muscovite with additive NaCl(muscovite:NaCl mass ratio of 1:1.00,900℃,45 min)followed by H_(2)SO_(4)-leaching(95℃,60 min)extracted potassium to the tune of 98%.Under similar roasting conditions,the H_(2)O-leaching process extracted only 60%of potassium.The effects of various roasting and leaching parameters such as temperature,time,NaCl concentration,acid concentration,liquid-solid ratio on potassium extraction were evaluated.The appearance of the sylvite(KCl)mineral phase in the NaCl-roasted muscovite and its disappearance in the acid/water leached residue confirmed the physical and chemical distortions of the muscovite crystal structure.The possible mechanism of potassium release from the complex muscovite structure was elucidated based on available literature substantiated by characterizations using X-ray diffraction(XRD)and scanning electron microscopy with energy dispersive X-rays spectroscopy(SEM-EDX).
文摘The present paper reports the effective utilization of marble sludge powder(MSP)for the recovery of potash values from waste mica scrap using chlorination roasting-water leaching method.Characterization studies indicated the presence of dolomite as the major mineral phase in MSP,whereas muscovite and quartz were observed in the mica sample.The acid leaching studies suggest a maximum of 22%potash recovery under conditions:4 M H2SO4 acid,particle size of^100μm,stirring speed of 600 r/min,leaching temperature of 75℃,and leaching time of 90 min.The chlorination roasting-water leaching process was adopted to achieve the lowest level of 80%-90%potash recovery.The optimum conditions for the recovery of^93%potash from mica(~8.6wt%K2O)requires 900℃ roasting temperature,30 min roasting time,and 1:1:0.75 mass ratio of mica:MSP:NaCl.The roasting temperature and amount of NaCl are found to be the most important factors for the recovery process.The reaction mechanism suggests the formation of different mineral phases,including sylvite(KCl),wollastonite,kyanite,and enstatite,during roasting,which were confirmed by X-ray diffraction(XRD)analyses and scanning electron microscopy(SEM)morphologies.The MSP-blended NaCl additive is more effective for potash recovery compared with the other reported commercial roasting additives.
