Ca-bentonite can be converted into zeolites A through hydrothermal alkaline treatment by varying the synthetic parameters. This study focuses on the effect of initial Si/Al molar ratio, NaOH concentration on the type ...Ca-bentonite can be converted into zeolites A through hydrothermal alkaline treatment by varying the synthetic parameters. This study focuses on the effect of initial Si/Al molar ratio, NaOH concentration on the type of formed zeolite A. The Ca-bentonite (China, Fuxin)were mixed with an aqueous NaOH solution, Al(OH)3 powder and hydrothermally treated at about 90 ℃,12 h. Different types of zeolites (zeolite X, P, and A),sodalite were synthesized after the treatment. Zeolites were characterized and quantified by means of XRD and SEM analysis. Zeolite A predominantly formed with 0.5≤Si/Al≤2.0 was produced and zeolite X, P formed with Si/Al>2.0 under the 2.2mol/LNaOH concentration; Sodalite was also formed under high NaOH molarities. Shape of zeolite A is show the cube by the SEM micrograph.展开更多
Fly ash was used to prepare alumina and silica white, The 3 stages of the process are as follows: ammonium sulfate calcining, acid leaching and alkali dissolution. The optimum conditions for the experiments to determi...Fly ash was used to prepare alumina and silica white, The 3 stages of the process are as follows: ammonium sulfate calcining, acid leaching and alkali dissolution. The optimum conditions for the experiments to determine are as follows: molar ratio of (NH4)2SO4/Al2O3 is 6, the calcining time is 2h, he H2SO4 concentration is 20%, the leaching temperature is 80℃ and dissolution duration is 2h, the ratio of solution and solid reaction material is 6 for ammonium sulfate calcining and acid leaching stage, reaction time 30min, ratio of liquid to ore 5∶1, alkali concentration 45% and reaction temperature 95 ℃for the alkali dissolution stage. Under these conditions, the total leaching efficiencies of Al2O3 and SiO2 are 78.86% and 95%, respectively. The quality of the main products alumina and silica white can meet the national standards of GB/T24487-2009 and GB10517-89, respectively.展开更多
The TiO2/vermiculite composites were prepared by in-situ hydrolyzing reaction and in-situ dehydrating reaction of tetrabutyl titanate-hexadecyl trimethyl ammonium bromide intercalated vermiculite. The structural phase...The TiO2/vermiculite composites were prepared by in-situ hydrolyzing reaction and in-situ dehydrating reaction of tetrabutyl titanate-hexadecyl trimethyl ammonium bromide intercalated vermiculite. The structural phase transition of TiO2 in TiO2/vermiculite composites calcined at different temperatures was characterized by using XRD and Raman. The results show that at calcination temperature of 800℃ appeared the anatase phase of TiO2 in TiO2/vermiculite nanocomposites, while pure TiO2 is all converted to rutile at the same temperature. The average crystal size of TiO2 in TiO2/vermiculite nanocomposites and pure TiO2 both increase with the calcination temperature. The average grain size of TiO2 in TiO2/vermiculite nanocomposites is less than that of pure TiO2 at the same calcination temperature. The results also show that the silicon-oxygen structure in layered vermiculite structure can effectively depress the phase transformation from anatase to rutile, thus enhancing the transition temperature and inhibitting the growth of anatase crystals.展开更多
The flake-like basic magnesium carbonate was prepared from the ammonium sulfate leaching liquid of asbestos tailings. The method of X-ray diffraction, Fourier transform infrared spectra, TA-DTG and SEM analysis had be...The flake-like basic magnesium carbonate was prepared from the ammonium sulfate leaching liquid of asbestos tailings. The method of X-ray diffraction, Fourier transform infrared spectra, TA-DTG and SEM analysis had been used to research the influence of the reaction temperature on the phase, structure and morphology of the product during the preparation of the basic magnesium carbonate. The results indicates that the product was needle-like magnesium carbonate hydrate at the lower reaction temperature (from 35 ℃ to 65℃), with the increase of the reaction temperature (75 ℃ to 95 ℃ ), the needle-like magnesium carbonate hydrate (MgCO3·xH2O) transformed to flake-like basic magnesium carbonate [Mg5(CO3)4(OH)2·4H2O], the reaction temperature plays an important role in the preparation of flake-like basic magnesium carbonate, the preparation of flake-like basic magnesium carbonate was a nucleation-dissolution-recrystallization growth mechanism process.展开更多
The thermostability, structure, oxidized functional group and hydrophilic of the different reduction temperature of graphene oxide were investigated by TG-DTA, XRD, FTIR, Raman and Water contact angle analysis. There ...The thermostability, structure, oxidized functional group and hydrophilic of the different reduction temperature of graphene oxide were investigated by TG-DTA, XRD, FTIR, Raman and Water contact angle analysis. There are three stages in the process. The first stage, under 150℃, desorption of adsorbed water on the graphene oxide, hydrophilic is best. The second stage, at 150–300℃, thermal decomposition of partial oxide functional group, graphene oxide was partly thermal reduction, hydrophilic diminishing. The third stage, at 300–550℃, temperature of 300–450℃ when oxidized functional group of graphene oxide is further decomposition, hydrophilic further reduced, temperature of 450–550℃, the carbon skeleton of graphene oxide decomposition. The thermal reduction process of graphene oxide only removed the oxidized functional group their structural deficiencies have not been restored, but due to thermal reduction process and build new structure defect.展开更多
The glass-ceramics was prepared from coal fly ash, limestone and Na2CO3 by sintering processes. Effects of the crystallization temperature (850–1100 ℃) on crystallization behavior, microstructure, sintering characte...The glass-ceramics was prepared from coal fly ash, limestone and Na2CO3 by sintering processes. Effects of the crystallization temperature (850–1100 ℃) on crystallization behavior, microstructure, sintering character and chemical stability of the glass-ceramics samples were analyzed by means of DTA, XRD, SEM and other analytical methods. The results show that the main crystalline phase of as-prepared glass-ceramics after crystallization treatment is gehlenite (Ca2Al2SiO7). The species of crystalline phases keep the same, however, the main crystalline intensity, line shrinkage rate and bulk density increase first then decrease with the increasing of heat treatment temperature. Water absorption of the samples was reduced as the heat treatment temperature rising. The glass-ceramics display high performance crystallization properties and chemical stability. The optimized glass-ceramics with desired sintering character and chemical stability was obtained by crystallized at 1050 ℃.展开更多
The hydrated-titanium-oxide/montmorillonite composite samples were prepared using a hydrolysation- intercalation composite method by controlling the amount of TiOSO4·2H2O. The TiO2/montmorillonite composite sampl...The hydrated-titanium-oxide/montmorillonite composite samples were prepared using a hydrolysation- intercalation composite method by controlling the amount of TiOSO4·2H2O. The TiO2/montmorillonite composite samples were got after calculated at 700℃ and 1100 ℃. The results show that: when the value of Ti/montmorillonite is 12.5 mmol/g, the c axis of hydrated-titanium-oxide/ montmorillonite composite sample began to disorder, moreover, the crystal size of anatase is just 13.4nm in the TiO2/montmorillonite composite sample calculated at 700 ℃, and after calculated at 1100 ℃, the crystal size of anatase is 55.8 nm, and the relative content of anatase reaches the highest (55.7%). Compared with pure TiO2 nano-particle sample, TiO2/montmorillonite composite sample has a higher phase transition temperature from anatase phase to rutile phase and smaller crystal size of TiO2. Montmorillonite structure layer has a significant blocking effect on TiO2 phase transformation and grain growth, and the blocking effect reaches saturation when the value of Ti/montmorillonite is 12.5 mmol/g.展开更多
文摘Ca-bentonite can be converted into zeolites A through hydrothermal alkaline treatment by varying the synthetic parameters. This study focuses on the effect of initial Si/Al molar ratio, NaOH concentration on the type of formed zeolite A. The Ca-bentonite (China, Fuxin)were mixed with an aqueous NaOH solution, Al(OH)3 powder and hydrothermally treated at about 90 ℃,12 h. Different types of zeolites (zeolite X, P, and A),sodalite were synthesized after the treatment. Zeolites were characterized and quantified by means of XRD and SEM analysis. Zeolite A predominantly formed with 0.5≤Si/Al≤2.0 was produced and zeolite X, P formed with Si/Al>2.0 under the 2.2mol/LNaOH concentration; Sodalite was also formed under high NaOH molarities. Shape of zeolite A is show the cube by the SEM micrograph.
文摘Fly ash was used to prepare alumina and silica white, The 3 stages of the process are as follows: ammonium sulfate calcining, acid leaching and alkali dissolution. The optimum conditions for the experiments to determine are as follows: molar ratio of (NH4)2SO4/Al2O3 is 6, the calcining time is 2h, he H2SO4 concentration is 20%, the leaching temperature is 80℃ and dissolution duration is 2h, the ratio of solution and solid reaction material is 6 for ammonium sulfate calcining and acid leaching stage, reaction time 30min, ratio of liquid to ore 5∶1, alkali concentration 45% and reaction temperature 95 ℃for the alkali dissolution stage. Under these conditions, the total leaching efficiencies of Al2O3 and SiO2 are 78.86% and 95%, respectively. The quality of the main products alumina and silica white can meet the national standards of GB/T24487-2009 and GB10517-89, respectively.
文摘The TiO2/vermiculite composites were prepared by in-situ hydrolyzing reaction and in-situ dehydrating reaction of tetrabutyl titanate-hexadecyl trimethyl ammonium bromide intercalated vermiculite. The structural phase transition of TiO2 in TiO2/vermiculite composites calcined at different temperatures was characterized by using XRD and Raman. The results show that at calcination temperature of 800℃ appeared the anatase phase of TiO2 in TiO2/vermiculite nanocomposites, while pure TiO2 is all converted to rutile at the same temperature. The average crystal size of TiO2 in TiO2/vermiculite nanocomposites and pure TiO2 both increase with the calcination temperature. The average grain size of TiO2 in TiO2/vermiculite nanocomposites is less than that of pure TiO2 at the same calcination temperature. The results also show that the silicon-oxygen structure in layered vermiculite structure can effectively depress the phase transformation from anatase to rutile, thus enhancing the transition temperature and inhibitting the growth of anatase crystals.
文摘The flake-like basic magnesium carbonate was prepared from the ammonium sulfate leaching liquid of asbestos tailings. The method of X-ray diffraction, Fourier transform infrared spectra, TA-DTG and SEM analysis had been used to research the influence of the reaction temperature on the phase, structure and morphology of the product during the preparation of the basic magnesium carbonate. The results indicates that the product was needle-like magnesium carbonate hydrate at the lower reaction temperature (from 35 ℃ to 65℃), with the increase of the reaction temperature (75 ℃ to 95 ℃ ), the needle-like magnesium carbonate hydrate (MgCO3·xH2O) transformed to flake-like basic magnesium carbonate [Mg5(CO3)4(OH)2·4H2O], the reaction temperature plays an important role in the preparation of flake-like basic magnesium carbonate, the preparation of flake-like basic magnesium carbonate was a nucleation-dissolution-recrystallization growth mechanism process.
文摘The thermostability, structure, oxidized functional group and hydrophilic of the different reduction temperature of graphene oxide were investigated by TG-DTA, XRD, FTIR, Raman and Water contact angle analysis. There are three stages in the process. The first stage, under 150℃, desorption of adsorbed water on the graphene oxide, hydrophilic is best. The second stage, at 150–300℃, thermal decomposition of partial oxide functional group, graphene oxide was partly thermal reduction, hydrophilic diminishing. The third stage, at 300–550℃, temperature of 300–450℃ when oxidized functional group of graphene oxide is further decomposition, hydrophilic further reduced, temperature of 450–550℃, the carbon skeleton of graphene oxide decomposition. The thermal reduction process of graphene oxide only removed the oxidized functional group their structural deficiencies have not been restored, but due to thermal reduction process and build new structure defect.
文摘The glass-ceramics was prepared from coal fly ash, limestone and Na2CO3 by sintering processes. Effects of the crystallization temperature (850–1100 ℃) on crystallization behavior, microstructure, sintering character and chemical stability of the glass-ceramics samples were analyzed by means of DTA, XRD, SEM and other analytical methods. The results show that the main crystalline phase of as-prepared glass-ceramics after crystallization treatment is gehlenite (Ca2Al2SiO7). The species of crystalline phases keep the same, however, the main crystalline intensity, line shrinkage rate and bulk density increase first then decrease with the increasing of heat treatment temperature. Water absorption of the samples was reduced as the heat treatment temperature rising. The glass-ceramics display high performance crystallization properties and chemical stability. The optimized glass-ceramics with desired sintering character and chemical stability was obtained by crystallized at 1050 ℃.
文摘The hydrated-titanium-oxide/montmorillonite composite samples were prepared using a hydrolysation- intercalation composite method by controlling the amount of TiOSO4·2H2O. The TiO2/montmorillonite composite samples were got after calculated at 700℃ and 1100 ℃. The results show that: when the value of Ti/montmorillonite is 12.5 mmol/g, the c axis of hydrated-titanium-oxide/ montmorillonite composite sample began to disorder, moreover, the crystal size of anatase is just 13.4nm in the TiO2/montmorillonite composite sample calculated at 700 ℃, and after calculated at 1100 ℃, the crystal size of anatase is 55.8 nm, and the relative content of anatase reaches the highest (55.7%). Compared with pure TiO2 nano-particle sample, TiO2/montmorillonite composite sample has a higher phase transition temperature from anatase phase to rutile phase and smaller crystal size of TiO2. Montmorillonite structure layer has a significant blocking effect on TiO2 phase transformation and grain growth, and the blocking effect reaches saturation when the value of Ti/montmorillonite is 12.5 mmol/g.
