In this study,ceramics was prepared by slip casting(no pressure was used during shaping step)and atmospheric pressure sintering with low-melting point glass(LPG)powder as the binding material to facilitate the transfo...In this study,ceramics was prepared by slip casting(no pressure was used during shaping step)and atmospheric pressure sintering with low-melting point glass(LPG)powder as the binding material to facilitate the transformation of spodumene flotation tailings(SFTs)into ceramics at lower temperatures.The influence of sintering temperature and mass ratio of LPG on the mechanical properties(flexural strength and compressive strength)of ceramic materials was studied by orthogonal test.The results showed that when the mass ratio of LPG powder was higher than or equal to 20 wt%and the sintering temperature was higher than or equal to 550℃,mutual adhesion between the sample particles was realised and consequently the ceramic materials could be prepared with good mechanical properties(the maximum flexural strength=19.55 MPa,the maximum compressive strength=42.25 MPa,average porosity=24.52%,average apparent density=1.66 g/cm^(3),and average water absorption=14.79%).The sintered ceramics were characterized by XRF,XRD,optical microscopy analysis,SEM,TGA-DSC and FT-IR.The formation of liquid phase at high temperature may lead to the mutual bonding between particles,which might be the main reason for the improvement of mechanical properties of ceramic materials.Overall,SFTs were successfully sintered at low temperature to prepare ceramic materials with good mechanical properties,which are crucial for energy conservation and environmental preservation.展开更多
Electrolytic manganese residue leachate(EMRL)contains plenty of Mn^(2+) and NH_(4)^(+)-N,and phosphogypsum leachate(PGL)contains large amounts of PO_(4)^(3-)-P and F^(-).Traditional methods of EMRL and PGL discharge c...Electrolytic manganese residue leachate(EMRL)contains plenty of Mn^(2+) and NH_(4)^(+)-N,and phosphogypsum leachate(PGL)contains large amounts of PO_(4)^(3-)-P and F^(-).Traditional methods of EMRL and PGL discharge could seriously damage the ecological environment.In this study,an innovative method for cooperative removal Mn^(2+),NH_(4)^(+)-N,PO_(4)^(3-)-P,F^(-)from PG and POFT was studied.The result showed that Mn^(2+),PO_(4)^(3-)-P and F^(-)were mainly removed in forms of Mg_(3)Si_(4)O_(10)(OH)_(2),Mn_(3)O_(4),Mn_(3)(PO_(4))_(2),Mg_(3)(PO_(4))_(2),CaSO_(4)·2H_(2)O,MnF_(2),MnOOH and Ca_(2)P_(2)O_(7)·2H_(2)O,when LG-MgO was used to adjust the pH value of the system to 9.5,and the volume ratio of EMRL and PGL was 1:4,as well as reaction for 1 h at 25℃.NH_(4)^(+)-N was mainly removed by struvite precipitate,when the molar ratio of N:Mg:P was 1:3:2.4.The concentrations of Mn^(2+),NH_(4)^(+)-N and F^(-)were lower than the integrated wastewater discharge standard.The concentration of PO_(4)^(3-)-P decreased from 254.20 mg/L to 3.21 mg/L.This study provided a new method for EMRL and PGL cooperative harmless treatment.展开更多
Effects of particle size and chain length on flotation of quaternary ammonium salts (QAS) onto kaolinite have been investigated by mico-flotation tests. The two kinds of quaternary ammonium salts [RN(CH3)3] with diffe...Effects of particle size and chain length on flotation of quaternary ammonium salts (QAS) onto kaolinite have been investigated by mico-flotation tests. The two kinds of quaternary ammonium salts [RN(CH3)3] with different chain lengths, dodecyltrimethylammonium chloride (DTAC) and cetyltrimethylammonium chloride (CTAC) were used as collectors for kaolinite in different particle size fractions (0.075–0.01 mm, 0.045–0.075 mm, 0–0.045 mm). The anomalous flotation behavior of kaolinite have been further explained based on crystal structure considerations by adsorption tests and molecular dynamics (MD) simulation. The results show that the flotation recovery of kaolinite in all different particle size fractions decreases with an increase in pH when DTAC and CTAC are used as collectors. As the concentration of collectors increases, the flotation recovery increases. The longer the carbon chain of QAS is, the higher the recoveries of coarse kaolinite (0.075–0.01 mm and 0.045–0.075 mm) are. But the flotation recovery of the finest kaolinite (0–0.045 mm) decreases with chain lengths of QAS collectors increasing, which is consistent with the flotation results of unsifted kaolinite (0–0.075 mm). It is explained by the froth stability related to the residual concentration of QAS collector. In lower residual concentration, the froth stability becomes worse. Within the range of flotation collector concentration, it's easy of CTAC to be completely adsorbed by kaolinite in the particle size fraction (0–0.045 mm), which led to lower flotation recovery. Moreover, it is interesting that the particle size of kaolinite is coarser, the flotation recovery is higher. The anomalous flotation behavior of kaolinite is rationalized based on crystal structure considerations. The results of MD simulations show that the (001) kaolinite surface has the strongest interaction with DTAC, compared with the (001), (010) and (110) surfaces. On the other hand, when particle size of kaolinite is altered, the number of basal planes and edge planes is changed. It is observed that the finer kaolinite particles size become, the greater relative surface area of edges is, and the more the number of edges is. It means that fine kaolinite particles have more edges to adsorb less cationic colletors than that of coarse kaolinite particles, which is responsible for the poorer floatability of fine kaolinite.展开更多
In order to know the particle size distribution and mineral compositions of dust in Maiji town, Tianshui City, Gansu Province, size distribution and physical compositions of atmosphere natural dropping dust have been ...In order to know the particle size distribution and mineral compositions of dust in Maiji town, Tianshui City, Gansu Province, size distribution and physical compositions of atmosphere natural dropping dust have been analyzed. Based on the natural dropping dust ζ potential and the mass percentage of main mineral compositions in dust fall, we present two models (calculation method and hybrid method) for the zeta potential of atmospheric dust fall in pure water. The results illustrated that the natural dropping dust in Maiji town belongs to inhalable particles. The main mineral compositions and contents of the dust are quartz (57.08%), calcite (27.79%), albite (10.29%), muscovite (4.84%). Atmospheric dust fall in pure water is electronegativity and ζ potential decreased with increasing pH. There are some differences exist in the two modeling ways, but have a similar tendency. The zeta potential differences between natural dropping dust and modeling dust reflects the zeta potential contribution rate of main mineral particles in dust and the effect of trace polarity organic pollutants or other minerals.展开更多
Xianfeng large-scale lignite mining area, symbiotic diatomaceous earth mining area is the second largest diatomaceous earth mining in China with high organic matter content. The Xianfeng diatomaceous earth mining is a...Xianfeng large-scale lignite mining area, symbiotic diatomaceous earth mining area is the second largest diatomaceous earth mining in China with high organic matter content. The Xianfeng diatomaceous earth mining is a difficult development and utilization of low-grade diatomaceous earth, which has not been effective utilized due to low economic value of traditional processes. The objectives of this paper are utilizing high organic matter content diatomite as waste resources and improving the comprehensive utilization ratio of mineral resources in Xianfeng coal mining areas. The high organic content diatomaceous earth was purified by the acid washing and then calcinations under N2 as a protective atmosphere and high temperature of 500 to 800 ℃. The organic matter was carbonized with the formation of amorphous complex of activated carbon and diatomaceous earth. The novel ternary composited diatomaceous earth was prepared by combining carbonation diatomaceous earth and magnetic nanomaterials. The absorption property of ternary composited diatomaceous earth was improved through the organosilane and polyacrylamide modification to meet the needs of practical application. Electron microscopy showed that magnetic precursor calcined under N2 as a protective atmosphere, the surface of the magnetic nanoparticles were coated with amorphous carbon, which improved chemical stability and compatibility with diatomaceous earth. The magnetic nanoparticles and amorphous activated carbon uniformly dispersed in a diatomaceous earth surface and within the pores, to form a stable magnetic nanoparticles - the amorphous active carbon - ternary complexes. The specific surface area and methylene blue adsorption test showed ternary composited diatomaceous earth performing much higher than conventional diatomite products, the novel diatomaceous earth with specific surface area of 55.79 m2/g, methylene blue adsorption capacity of 44.5 m2/g. MgFe2O4 and Co3O4-based superparamagnetic ternary composited diatomaceous earth as an unique adsorbent has great application potential in organic pollutants and heavy metals pollution treatment of water. In addition, the CoFe2O4 based soft magnetic ternary composited diatomaceous earth has potential applications in magnetic plastics, rubber functional filler fields. This study shows that the proposed technology is conducive to a substantial increasing economic value of the Xianfeng diatomaceous earth mining, has a broad industrial application prospects.展开更多
The novel high-performance nanocomposites of polyaniline (PANI) and graphene oxide sheets (GOs) was synthesized via in situ polymerization in the presence of Hexadecyl trimethyl ammonium Bromide intercalated graphite ...The novel high-performance nanocomposites of polyaniline (PANI) and graphene oxide sheets (GOs) was synthesized via in situ polymerization in the presence of Hexadecyl trimethyl ammonium Bromide intercalated graphite oxide (CGO), basing on PANI and GOs as a matrix respectively. The result showed that ANI monomer was intercalated into the spacing of CGO, and the CGO was well exfoliated into nanosheets while polymerization. Owing to π–π electron stacking effect between the PANI and the GOs, the electrical conductivity of GOs/PANI nanocomposites (0.47 S/cm), which basing on PANI as a matrix, improved in comparison with pure PANI nanowires (0.02 S/cm) and GO (2.5×10-5 S/cm), while the electrical conductivity of PANI/GOs nanocomposites, which basing on GOs as a matrix, was only 6.2×10-3 S/cm. And it also indicated that the mole ratio of APS, the concentration of HCl, other with the polymerization time, are also important influencing factors of the conductivity of nanocomposites.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
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
In this study A549 cell viability, extracellular activities of lactate dehydrogenase (LDH), tumor necrosis factor (TNF)–α and interleukin (IL)-6 levels were investgated after incubation with quartz (KWC-Q4 and KWC-Q...In this study A549 cell viability, extracellular activities of lactate dehydrogenase (LDH), tumor necrosis factor (TNF)–α and interleukin (IL)-6 levels were investgated after incubation with quartz (KWC-Q4 and KWC-Q3), Nano-SiO2, and KWC-M, the micronucleaus test and comet assay was carried out to evaluate the genotoxicity. The results showed that, there were significant difference in the cell death rate and extracellular LDH activity compared with the control group, and appeared a good linear relationship in certain concentration range. All mineral particle tested can induce the increase of TNF-α after incubation with mineral powders at 200 μg/mL for 3h merely, and significant increase of IL-6 for 24h, the results indicated the inflammatory reaction can be triggered by the exposure of KWC-Q4, KWC-Q3, Nano-SiO2, and KWC-M. The micronucleus test result showed the MNF (Micronucleus frequency) listed as Nano-SiO2>KWC-Q3>KWC-Q4. There is no significant increase of KWC-M compared with the control group, maybe resulted from its high cell death rate at low concentration. The comet assay confirmed the genotoxicity of all samples tested, the DNA damage: KWC-M > Nano-SiO2 > KWC-Q4 > KWC-Q3.展开更多
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
After the sewage treatment, putting the wet sludge in which the heavy metal content is extremely low, corrupt and broken straw, bentonite, urea in proportioning according to the certain ratio, mixing well-distributed,...After the sewage treatment, putting the wet sludge in which the heavy metal content is extremely low, corrupt and broken straw, bentonite, urea in proportioning according to the certain ratio, mixing well-distributed, taking the shape of Nitrogen slow-release fertilizers, doing the dynamic bioleaching test by the method of Artificial rainfall simulation, researching the slow-release characteristic, water retention. When the mass ratio of the wet sludge whose water content is 82.5%: bentonite: corrupt and broken straw: urea is 62.5: 12.5: 12.5: 12.5, drip washing the 10g Nitrogen slow-release fertilizers by the 80ml distilled water after 48h, the residue rate of urea is 29.63%; Under the room temperature of 25 ℃, 77%RH, moisture evaporate 46.32% after 60 h. The results demonstrate that the slow-release fertilizer has a good release-effect of nitrogen and water conservation effect. It provides the basic for the development and application of the sewage in the aspect of Nitrogen slow-release fertilizers.展开更多
Produced by the production of sulfuric acid from kaolinite type when the Fe2O3 and metakaolin together constitute the kaolinite type pyrite cinder is a typical industrial solid waste. Only in southern Sichuan China st...Produced by the production of sulfuric acid from kaolinite type when the Fe2O3 and metakaolin together constitute the kaolinite type pyrite cinder is a typical industrial solid waste. Only in southern Sichuan China storage capacity has reached millions of tons, that caused serious impact on ecology and environment in this area. It also caused serious waste of resources. The magnetite concentrate and given priority to with partial kaolinite pyrite cinder tailings that were obtained by grinding and magnetic separation. This experiment studied the relationship composition and particle size with its activity when cinder tailings as cement mixed material. The results show that the particle size of D90 were 88 micron, 56 micron, 40 micron, the activity index were 1.036, 1.068, 1.102. The slag after magnetic separation is a kind of very good activity of cement mixed material. It can make good use of the industrial solid waste.展开更多
The Influence of pulp pH, dispersants and auxiliary collectors on reverse flotation of carbonate-containing iron ores were explored. Interactions between iron ores and quartz were theoretically analyzed by flotation s...The Influence of pulp pH, dispersants and auxiliary collectors on reverse flotation of carbonate-containing iron ores were explored. Interactions between iron ores and quartz were theoretically analyzed by flotation solution chemistry and DLVO theory. The results indicated that the iron concentrate grade improved sharply when pH increased from 11.0 to 12.0, but changed unobviously when pH was larger than 12.0, which was related to solution chemistry of siderite and interactions among particles. Sodium tripolyphosphate was an effective dispersant and sodium dodecyl sulfate was an effective auxiliary collector of KS-III. Both recovery and grade enhanced by the action of sodium dodecyl sulfate or sodium tripolyphosphate when pH was 12.0.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 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
基金Projects(51674207,51922091)supported by the National Natural Science Foundation of ChinaProject(2018QNRC001)supported by the Young Elite Scientists Sponsorship Program by CAST,ChinaProjects(2019YFS0453,2018JY0148)supported by the Sichuan Science and Technology Program,China。
文摘In this study,ceramics was prepared by slip casting(no pressure was used during shaping step)and atmospheric pressure sintering with low-melting point glass(LPG)powder as the binding material to facilitate the transformation of spodumene flotation tailings(SFTs)into ceramics at lower temperatures.The influence of sintering temperature and mass ratio of LPG on the mechanical properties(flexural strength and compressive strength)of ceramic materials was studied by orthogonal test.The results showed that when the mass ratio of LPG powder was higher than or equal to 20 wt%and the sintering temperature was higher than or equal to 550℃,mutual adhesion between the sample particles was realised and consequently the ceramic materials could be prepared with good mechanical properties(the maximum flexural strength=19.55 MPa,the maximum compressive strength=42.25 MPa,average porosity=24.52%,average apparent density=1.66 g/cm^(3),and average water absorption=14.79%).The sintered ceramics were characterized by XRF,XRD,optical microscopy analysis,SEM,TGA-DSC and FT-IR.The formation of liquid phase at high temperature may lead to the mutual bonding between particles,which might be the main reason for the improvement of mechanical properties of ceramic materials.Overall,SFTs were successfully sintered at low temperature to prepare ceramic materials with good mechanical properties,which are crucial for energy conservation and environmental preservation.
基金Project(2018YFC1903500)supported by the National Key Research and Development Program of ChinaProject(52174386)supported by the National Natural Science Foundation of ChinaProject(2021YFH0058)supported by the Science and Technology Plan Project of Sichuan Province,China。
文摘Electrolytic manganese residue leachate(EMRL)contains plenty of Mn^(2+) and NH_(4)^(+)-N,and phosphogypsum leachate(PGL)contains large amounts of PO_(4)^(3-)-P and F^(-).Traditional methods of EMRL and PGL discharge could seriously damage the ecological environment.In this study,an innovative method for cooperative removal Mn^(2+),NH_(4)^(+)-N,PO_(4)^(3-)-P,F^(-)from PG and POFT was studied.The result showed that Mn^(2+),PO_(4)^(3-)-P and F^(-)were mainly removed in forms of Mg_(3)Si_(4)O_(10)(OH)_(2),Mn_(3)O_(4),Mn_(3)(PO_(4))_(2),Mg_(3)(PO_(4))_(2),CaSO_(4)·2H_(2)O,MnF_(2),MnOOH and Ca_(2)P_(2)O_(7)·2H_(2)O,when LG-MgO was used to adjust the pH value of the system to 9.5,and the volume ratio of EMRL and PGL was 1:4,as well as reaction for 1 h at 25℃.NH_(4)^(+)-N was mainly removed by struvite precipitate,when the molar ratio of N:Mg:P was 1:3:2.4.The concentrations of Mn^(2+),NH_(4)^(+)-N and F^(-)were lower than the integrated wastewater discharge standard.The concentration of PO_(4)^(3-)-P decreased from 254.20 mg/L to 3.21 mg/L.This study provided a new method for EMRL and PGL cooperative harmless treatment.
文摘Effects of particle size and chain length on flotation of quaternary ammonium salts (QAS) onto kaolinite have been investigated by mico-flotation tests. The two kinds of quaternary ammonium salts [RN(CH3)3] with different chain lengths, dodecyltrimethylammonium chloride (DTAC) and cetyltrimethylammonium chloride (CTAC) were used as collectors for kaolinite in different particle size fractions (0.075–0.01 mm, 0.045–0.075 mm, 0–0.045 mm). The anomalous flotation behavior of kaolinite have been further explained based on crystal structure considerations by adsorption tests and molecular dynamics (MD) simulation. The results show that the flotation recovery of kaolinite in all different particle size fractions decreases with an increase in pH when DTAC and CTAC are used as collectors. As the concentration of collectors increases, the flotation recovery increases. The longer the carbon chain of QAS is, the higher the recoveries of coarse kaolinite (0.075–0.01 mm and 0.045–0.075 mm) are. But the flotation recovery of the finest kaolinite (0–0.045 mm) decreases with chain lengths of QAS collectors increasing, which is consistent with the flotation results of unsifted kaolinite (0–0.075 mm). It is explained by the froth stability related to the residual concentration of QAS collector. In lower residual concentration, the froth stability becomes worse. Within the range of flotation collector concentration, it's easy of CTAC to be completely adsorbed by kaolinite in the particle size fraction (0–0.045 mm), which led to lower flotation recovery. Moreover, it is interesting that the particle size of kaolinite is coarser, the flotation recovery is higher. The anomalous flotation behavior of kaolinite is rationalized based on crystal structure considerations. The results of MD simulations show that the (001) kaolinite surface has the strongest interaction with DTAC, compared with the (001), (010) and (110) surfaces. On the other hand, when particle size of kaolinite is altered, the number of basal planes and edge planes is changed. It is observed that the finer kaolinite particles size become, the greater relative surface area of edges is, and the more the number of edges is. It means that fine kaolinite particles have more edges to adsorb less cationic colletors than that of coarse kaolinite particles, which is responsible for the poorer floatability of fine kaolinite.
文摘In order to know the particle size distribution and mineral compositions of dust in Maiji town, Tianshui City, Gansu Province, size distribution and physical compositions of atmosphere natural dropping dust have been analyzed. Based on the natural dropping dust ζ potential and the mass percentage of main mineral compositions in dust fall, we present two models (calculation method and hybrid method) for the zeta potential of atmospheric dust fall in pure water. The results illustrated that the natural dropping dust in Maiji town belongs to inhalable particles. The main mineral compositions and contents of the dust are quartz (57.08%), calcite (27.79%), albite (10.29%), muscovite (4.84%). Atmospheric dust fall in pure water is electronegativity and ζ potential decreased with increasing pH. There are some differences exist in the two modeling ways, but have a similar tendency. The zeta potential differences between natural dropping dust and modeling dust reflects the zeta potential contribution rate of main mineral particles in dust and the effect of trace polarity organic pollutants or other minerals.
基金Supported by the Opening Project of Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education (11zxgk05)
文摘Xianfeng large-scale lignite mining area, symbiotic diatomaceous earth mining area is the second largest diatomaceous earth mining in China with high organic matter content. The Xianfeng diatomaceous earth mining is a difficult development and utilization of low-grade diatomaceous earth, which has not been effective utilized due to low economic value of traditional processes. The objectives of this paper are utilizing high organic matter content diatomite as waste resources and improving the comprehensive utilization ratio of mineral resources in Xianfeng coal mining areas. The high organic content diatomaceous earth was purified by the acid washing and then calcinations under N2 as a protective atmosphere and high temperature of 500 to 800 ℃. The organic matter was carbonized with the formation of amorphous complex of activated carbon and diatomaceous earth. The novel ternary composited diatomaceous earth was prepared by combining carbonation diatomaceous earth and magnetic nanomaterials. The absorption property of ternary composited diatomaceous earth was improved through the organosilane and polyacrylamide modification to meet the needs of practical application. Electron microscopy showed that magnetic precursor calcined under N2 as a protective atmosphere, the surface of the magnetic nanoparticles were coated with amorphous carbon, which improved chemical stability and compatibility with diatomaceous earth. The magnetic nanoparticles and amorphous activated carbon uniformly dispersed in a diatomaceous earth surface and within the pores, to form a stable magnetic nanoparticles - the amorphous active carbon - ternary complexes. The specific surface area and methylene blue adsorption test showed ternary composited diatomaceous earth performing much higher than conventional diatomite products, the novel diatomaceous earth with specific surface area of 55.79 m2/g, methylene blue adsorption capacity of 44.5 m2/g. MgFe2O4 and Co3O4-based superparamagnetic ternary composited diatomaceous earth as an unique adsorbent has great application potential in organic pollutants and heavy metals pollution treatment of water. In addition, the CoFe2O4 based soft magnetic ternary composited diatomaceous earth has potential applications in magnetic plastics, rubber functional filler fields. This study shows that the proposed technology is conducive to a substantial increasing economic value of the Xianfeng diatomaceous earth mining, has a broad industrial application prospects.
文摘The novel high-performance nanocomposites of polyaniline (PANI) and graphene oxide sheets (GOs) was synthesized via in situ polymerization in the presence of Hexadecyl trimethyl ammonium Bromide intercalated graphite oxide (CGO), basing on PANI and GOs as a matrix respectively. The result showed that ANI monomer was intercalated into the spacing of CGO, and the CGO was well exfoliated into nanosheets while polymerization. Owing to π–π electron stacking effect between the PANI and the GOs, the electrical conductivity of GOs/PANI nanocomposites (0.47 S/cm), which basing on PANI as a matrix, improved in comparison with pure PANI nanowires (0.02 S/cm) and GO (2.5×10-5 S/cm), while the electrical conductivity of PANI/GOs nanocomposites, which basing on GOs as a matrix, was only 6.2×10-3 S/cm. And it also indicated that the mole ratio of APS, the concentration of HCl, other with the polymerization time, are also important influencing factors of the conductivity of nanocomposites.
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.
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In this study A549 cell viability, extracellular activities of lactate dehydrogenase (LDH), tumor necrosis factor (TNF)–α and interleukin (IL)-6 levels were investgated after incubation with quartz (KWC-Q4 and KWC-Q3), Nano-SiO2, and KWC-M, the micronucleaus test and comet assay was carried out to evaluate the genotoxicity. The results showed that, there were significant difference in the cell death rate and extracellular LDH activity compared with the control group, and appeared a good linear relationship in certain concentration range. All mineral particle tested can induce the increase of TNF-α after incubation with mineral powders at 200 μg/mL for 3h merely, and significant increase of IL-6 for 24h, the results indicated the inflammatory reaction can be triggered by the exposure of KWC-Q4, KWC-Q3, Nano-SiO2, and KWC-M. The micronucleus test result showed the MNF (Micronucleus frequency) listed as Nano-SiO2>KWC-Q3>KWC-Q4. There is no significant increase of KWC-M compared with the control group, maybe resulted from its high cell death rate at low concentration. The comet assay confirmed the genotoxicity of all samples tested, the DNA damage: KWC-M > Nano-SiO2 > KWC-Q4 > KWC-Q3.
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After the sewage treatment, putting the wet sludge in which the heavy metal content is extremely low, corrupt and broken straw, bentonite, urea in proportioning according to the certain ratio, mixing well-distributed, taking the shape of Nitrogen slow-release fertilizers, doing the dynamic bioleaching test by the method of Artificial rainfall simulation, researching the slow-release characteristic, water retention. When the mass ratio of the wet sludge whose water content is 82.5%: bentonite: corrupt and broken straw: urea is 62.5: 12.5: 12.5: 12.5, drip washing the 10g Nitrogen slow-release fertilizers by the 80ml distilled water after 48h, the residue rate of urea is 29.63%; Under the room temperature of 25 ℃, 77%RH, moisture evaporate 46.32% after 60 h. The results demonstrate that the slow-release fertilizer has a good release-effect of nitrogen and water conservation effect. It provides the basic for the development and application of the sewage in the aspect of Nitrogen slow-release fertilizers.
文摘Produced by the production of sulfuric acid from kaolinite type when the Fe2O3 and metakaolin together constitute the kaolinite type pyrite cinder is a typical industrial solid waste. Only in southern Sichuan China storage capacity has reached millions of tons, that caused serious impact on ecology and environment in this area. It also caused serious waste of resources. The magnetite concentrate and given priority to with partial kaolinite pyrite cinder tailings that were obtained by grinding and magnetic separation. This experiment studied the relationship composition and particle size with its activity when cinder tailings as cement mixed material. The results show that the particle size of D90 were 88 micron, 56 micron, 40 micron, the activity index were 1.036, 1.068, 1.102. The slag after magnetic separation is a kind of very good activity of cement mixed material. It can make good use of the industrial solid waste.
文摘The Influence of pulp pH, dispersants and auxiliary collectors on reverse flotation of carbonate-containing iron ores were explored. Interactions between iron ores and quartz were theoretically analyzed by flotation solution chemistry and DLVO theory. The results indicated that the iron concentrate grade improved sharply when pH increased from 11.0 to 12.0, but changed unobviously when pH was larger than 12.0, which was related to solution chemistry of siderite and interactions among particles. Sodium tripolyphosphate was an effective dispersant and sodium dodecyl sulfate was an effective auxiliary collector of KS-III. Both recovery and grade enhanced by the action of sodium dodecyl sulfate or sodium tripolyphosphate when pH was 12.0.
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 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.
基金Projects(2019YFC1904903,2020YFC1806504)supported by the National Key R&D Program of ChinaProject(51978658)supported by the National Natural Science Foundation of ChinaProject(2023YQTD03)supported by the Central Universities Outstanding Youth Team Project of CUMTB,China。
