|
In this paper, using hydrochloric acid , sodium hydroxide calcined kaolin modified using differential thermal - thermal gravimetric analyzer , X-ray diffraction (XRD) , than the surface area tester , scanning electron microscopy , transmission electron microscopy and spectroscopy analysis testing means the kaolin change structure before and after sex , oil absorption study to determine the optimum conditions for kaolin modified , and modified kaolin pH modification process , while Al2O3 filtrate recycling . Further, in order to achieve modified kaolin industrialized production and to obtain a higher ratio of surface area of the modified kaolin , the present work were 31% industrial hydrochloric acid after the first base on kaolin modified attempt . The research results show that the ore kaolin complex composition , structure , and pore size distribution mainly in the large hole , and therefore smaller than the surface area . In order to improve its specific surface area must be its calcined at a certain temperature , and then the appropriate acid , an alkali - modified . This work was to determine the the best calcined kaolin acid treatment temperature of 850 ° C , the best alkali treatment calcined kaolin temperature of 1000 ° C . Kaolin optimum conditions of the acid-modified kaolin and acid feed ratio of 8ml / g , the reaction time was 2h , the reaction temperature was 90 ° C , the acid concentration of 4mol / L , the specific surface area of reach 468.1654m2 / g , than reported in the literature specific surface area of ??more than two-fold increase . Kaolin alkali modified optimum conditions for the feed ratio of the kaolin with the alkali 6mL / g, the reaction time was 2h , the reaction temperature was 90 ° C , the concentration of NaOH 3 mol / L , the ratio of surface area to 129.8048m2 / g . The improvement of the specific surface area of the acid , an alkali - modified kaolin products because of the acid , an alkali - modified , leaching of the kaolin Al, Si and other elements enrich the pore structure of kaolin . 31% of the industrial hydrochloric acid the calcined kaolin modified , 31% of industrial hydrochloric acid containing iron , chlorine and organic impurities , purity inadequate , resulting in its not calcined kaolin Al fully extracted , the leaching rate of oil absorption value and Al are small. Kaolin first acid after an alkali treatment , oil absorption value , specific surface area , pore volume are substantially reduced , which is due the alkali modified eluted Si expand the orifice left by the acid-modified Al dissolution so that the pore size increases .
|