Preparation of electronic grade manganese sulfate from ferromanganese slag, including grinding, leaching and purification, was studied. The impurities, such as Fe3+, Al3+, Ca2+, Mg2+, heavy metal ions and Na+, K+, wer...Preparation of electronic grade manganese sulfate from ferromanganese slag, including grinding, leaching and purification, was studied. The impurities, such as Fe3+, Al3+, Ca2+, Mg2+, heavy metal ions and Na+, K+, were removed from leaching solution by neutralized-hydrolysis, fluorination precipitation, sulfuration precipitation and re-crystallization. Effects of pH of reaction, temperature and dosage of the different additives on removal rates of the metallic ions in leaching solution were investigated, and the suitable temperature, pH and the added amount of precipitating agent were obtained. The prepared manganese sulfate product, of which the mass fractions of Ca2+, Mg2+, Na+, K+ are all smaller than 0.005%, the mass fractions of Fe3+, Al3+ and heavy metal ions are smaller than 0.001%, and the mass fraction of Mn2+ is greater than 32%, can meet the demand of anode materials of lithium-ion batteries.展开更多
China is a big producer and consumer of tea. A huge amount of tea waste is produced in China every year, resulting in environmental pollution and enormous natural resources waste. From the perspective of utilization w...China is a big producer and consumer of tea. A huge amount of tea waste is produced in China every year, resulting in environmental pollution and enormous natural resources waste. From the perspective of utilization way, this pa- per summarized the research progresses in tea waste as a raw material for ex- tracting active ingredients and preparing absorbent, activated carbon, bio-organic fer- tilizer, animal feed and nutrients for edible fungi cultivation. In addition, the develop- ment trend of comprehensive utilization of tea waste was prospected. It is found that the comprehensive utilization of tea waste using a variety of techniques can im- prove the utilization efficiency of tea waste and reduce production costs. Finally, a simple and practical comprehensive utilization program was proposed to provide a reference for practical application.展开更多
A kind of industrial solid waste, i.e., carbide slag, was used as CaO precursor to synthesize CO2 sorbent. The highly reactive synthetic sorbent was prepared from carbide slag, aluminum nitrate hydrate and glycerol wa...A kind of industrial solid waste, i.e., carbide slag, was used as CaO precursor to synthesize CO2 sorbent. The highly reactive synthetic sorbent was prepared from carbide slag, aluminum nitrate hydrate and glycerol water solution by the combustion synthesis method. The results show that the synthetic sorbent exhibits a much higher CO2 capture capacity compared with carbide slag. The CO2 capture capacity and the carbonation conversion of the synthetic sorbent are 0. 38 g/g and 0. 70 after 50 cycles, which are 1.8 and 2. 1 times those of carbide slag. The average carbonation conversion and the CO2 capture efficiency of the synthetic sorbent are higher than those of carbide slag with the same sorbent flow ratios. The required sorbent flow ratios are lower for synthetic sorbent to achieve the same CO2 capture efficiency compared with carbide slag. With the same sorbent flow ratio and CO2 capture efficiency, the energy requirement in calciner for the synthetic sorbent is less than that for carbide slag.展开更多
The reduction smelting process for cobalt recovery from converter slag of the Chambishi Copper Smelter in Zambia was studied. The effects of reducing agent dosage, smelting temperature and time and the addition of sla...The reduction smelting process for cobalt recovery from converter slag of the Chambishi Copper Smelter in Zambia was studied. The effects of reducing agent dosage, smelting temperature and time and the addition of slag modifiers (CaO and TiO2) were investigated. In addition, the depleted slag and cobalt-bearing alloy were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Under the determined conditions, 94.02% Co, 95.76% Cu and less than 18% Fe in the converter slag were recovered. It was found that the main phases of depleted slag were fayalite and hercynite; and the cobalt-bearing alloy mainly contained metallic copper, Fe-Co-Cu alloys and a small amount of sulfide.展开更多
The oxidizing roasting process of carbon ferrochrome to prepare potassium chromate in the presence of potassium carbonate and air was investigated. The effects of reaction temperature, reaction time, mole ratio of pot...The oxidizing roasting process of carbon ferrochrome to prepare potassium chromate in the presence of potassium carbonate and air was investigated. The effects of reaction temperature, reaction time, mole ratio of potassium carbonate to carbon ferrochrome were studied, and thermodynamics and kinetics were also discussed. It was observed that the reaction temperature and reaction time had a significant influence on the roasting reaction of carbon ferrochrome. The reaction mechanism changed greatly as the temperature varied. A two-stage roasting process was favorable for the roasting reaction, and a chromium recovery rate of 97.06% was obtained through this two-stage roasting method. The chromium residue yielded from this method was only 1/3 of the product. Moreover, the component of Fe in the residue was as high as 55.04%. Therefore, it can be easily recovered to produce sponge iron, realizing complete detoxication and zero-emission of chromium residue.展开更多
Preliminary study on concentration and separation of tin(Sn) from copper alloy dross by selective dissolution method was conducted. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution...Preliminary study on concentration and separation of tin(Sn) from copper alloy dross by selective dissolution method was conducted. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution which could allow separation of tin from the copper alloy dross. The tin as H2SnO3(metastannic acid) phase was precipitated in the solution with centrifuging process and transformed to tin dioxide(SnO2) after drying process. The dried sample was heat-treated at low temperature and its phase characteristics, surface morphology and chemical composition were investigated.展开更多
In 2008,around 596 000 t of aluminum dross was generated from secondary aluminum industry in China;however,it was not sufficiently recycled yet.Approximately 95% of the Al dross was land filled without innocent treatm...In 2008,around 596 000 t of aluminum dross was generated from secondary aluminum industry in China;however,it was not sufficiently recycled yet.Approximately 95% of the Al dross was land filled without innocent treatment.The purpose of this work is to investigate Al dross recycling by environmentally efficient and friendly methods.Two methods of Al dross recycling which could utilize Al dross efficiently were presented.High-quality aluminum-silicon alloys and brown fused alumina(BFA) were produced successfully by recycling Al dross.Then,life cycle assessment(LCA) was performed to evaluate environmental impact of two methods of Al dross recycling process.The results show that the two methods are reasonable and the average recovery rate of Al dross is up to 98%.As the LCA results indicate,they have some advantages such as less natural resource consumption and pollutant emissions,which efficiently relieves the burden on the environment in electrolytic aluminum and secondary aluminum industry.展开更多
We report the adsorption of phosphate and discuss the mechanisms of phosphate removal from aqueous solution by burst furnace slag (BFS) and steel furnace slag (SFS). The results show that the adsorption of phosphate o...We report the adsorption of phosphate and discuss the mechanisms of phosphate removal from aqueous solution by burst furnace slag (BFS) and steel furnace slag (SFS). The results show that the adsorption of phosphate on the slag was rapid and the majority of adsorption was completed in 5~10 min. The adsorption capacity of phosphate by the slag was reduced dramatically by acid treatment. The relative contribution of adsorption to the total removal of phosphate was 26%~28%. Phosphate adsorption on BFS and SFS follows the Freundlich isotherm, with the related constants of k 6.372 and 1/n 1.739 for BFS, and of k 1.705 and 1/n 1.718 for SFS. The pH and Ca2+ concentration were decreased with the addition of phosphate, suggesting the formation of calcium phosphate precipitation. At pH 2.93 and 6.93, phosphate was desorbed by about 36%~43% and 9%~11%, respectively. These results indicate that the P adsorption on the slag is not completely reversible and that the bond between the slag particles and adsorbed phosphate is strong. The X-ray diffraction (XRD) patterns of BFS and SFS before and after phosphate adsorption verify the formation of phosphate salts (CaHPO4·2H2O) after adsorption process. We conclude that the removal of phosphate by BFS and SFS is related to the formation of phosphate calcium precipitation and the adsorption on hydroxylated oxides. The results show that BFS and SFS removed phosphate nearly 100%, indicating they are promising adsorbents for the phosphate removal in wastewater treatment and pollution control.展开更多
Using seawater in concrete can be considered as one of the sustainable approaches in construction industry not only to save the freshwater resource but also to promote the use of abandoned seawater resource, especiall...Using seawater in concrete can be considered as one of the sustainable approaches in construction industry not only to save the freshwater resource but also to promote the use of abandoned seawater resource, especially in the construction at the uninhabited area close to the sea where the procurement of fresh water is difficult. In this study, durability against chloride attack of seawater mixed concrete with different replacement ratio of BFS (blast furnace slag) and FA (fly ash) is discussed and the life time until the occurrence of corrosion crack is evaluated. The results show that: (1) Chloride penetration rate of seawater mixed specimens with BFS and FA is lower than that of freshwater mixed OPC (ordinary Portland cement) specimens; (2) Oxygen permeability of seawater mixed specimens with BFS and FA is almost the same or lower than that of freshwater mixed OPC specimens; (3) Total life time (corrosion incubation period and propagation period) of seawater mixed specimens with BFS and FA is almost the same or only slightly shorter than that of freshwater mixed OPC specimens. From the results, it was confirmed that the usage of seawater in concrete mixing is feasible in concrete with the appropriate BFS and FA replacement ratio.展开更多
A direct production method of high-strength titanium alloy from upgraded titania slag(UGS)was developed.First,UGS was reduced into alloy powder with 1.3 wt.%oxygen using magnesium powder.Subsequently,the alloy powder ...A direct production method of high-strength titanium alloy from upgraded titania slag(UGS)was developed.First,UGS was reduced into alloy powder with 1.3 wt.%oxygen using magnesium powder.Subsequently,the alloy powder was compacted at 600 MPa to produce a pellet.Lastly,the pellet was sintered to produce titanium alloy.The reduced powder was characterized,and the effect arising from the sintering temperature on the sintered density,compressive strength,microstructure,and hardness of the alloys was studied.The results showed that the density tended to increase with the temperature increasing from 900 to 1200℃,whereas the porosity decreased.A significant sintering densification was achieved at the temperature above 1100℃(98.65%at 1100℃ and 99.41%at 1200℃).At 1100℃,the hardness and compressive strength reached the maximal values of the alloy,HV 655.7 and 1563 MPa,respectively.展开更多
The effects of MgO/Al2 O3 ratio on the viscous behaviors of MgO-Al2 O3-TiO2-CaO-SiO2 systems were investigated by the rotating cylinder method.Raman spectroscopy was used to analyze the structural characteristics of s...The effects of MgO/Al2 O3 ratio on the viscous behaviors of MgO-Al2 O3-TiO2-CaO-SiO2 systems were investigated by the rotating cylinder method.Raman spectroscopy was used to analyze the structural characteristics of slag and Factsage 7.0 was adopted to demonstrate the liquidus temperature of slag.The results show that the viscosity and activation energy for viscous flow decrease when the MgO/Al2O3 ratio increases from 0.82 to 1.36.The break point temperature and liquidus temperature of slag initially decrease and subsequently increase.The complex viscous structures are gradually depolymerized to simple structural units.In conclusion,with the increase of MgO/Al2O3 ratio,the degree of polymerization of slag decreases,which improves the fluidity of slag.The variations of liquidus temperature of slag lead to the same changes of break point temperature.展开更多
With titanium-bearing blast furnace slag, ammonium sulfate, citric acid and potassium carbonate as raw materials to produce foliar fertilizer and Ca-S-Si compound fertilizer by means of heating process for the first t...With titanium-bearing blast furnace slag, ammonium sulfate, citric acid and potassium carbonate as raw materials to produce foliar fertilizer and Ca-S-Si compound fertilizer by means of heating process for the first time, which improved the solubility of the slag and converted the nutritional elements into such ones which are prone to be absorbed by plants. The effects of process conditions on dissolution rate of titanium were mainly analyzed through the orthogonal experiment. The results showed that the optimum synthesis process conditions of foliar fertilizer from the slag were 360 ℃ for 35 min, the mass ratio of ammonium sulfate and titanium-bearing blast furnace slag was 8:1. Under these conditions more than 80% of iron, titanium, magnesium and part of silicon in titanium-bearing blast furnace slag converted into water-soluble substances and existing in foliar fertilizer. Foliar fertilizer contained nitrogen, sulfur, potassium, iron, titanium, magnesium and silicon, and pH value of foliar fertilizer was 6. Ca-S-Si compound fertilizer mainly contained calcium silicate and calcium sulfate, which existed in the form of citric acid-soluble substance and slightly soluble substance, respectively.展开更多
[Objective] The aim was to optimize the appropriate solid state fermentation(SSF)conditions.[Method] The optimization of solid state fermentation using a mixture substrate of bean curd residue and the marc with Bacill...[Objective] The aim was to optimize the appropriate solid state fermentation(SSF)conditions.[Method] The optimization of solid state fermentation using a mixture substrate of bean curd residue and the marc with Bacillus natto was developed.[Result] The best fermentation condition optimized by the test of single factor and the orthogonal design respectively was mixing ratio of bean curd residue to marc 2∶1,substrate pH value 6,fermentation temperature 39 ℃,inoculum volume 10% and fermentation time 48 h.Under this optimized fermentation condition,the content of crude fiber in the substrate decreased from 107.8 mg/g before SSF to 56.2 mg/g after SSF,and the degeneration rate of crude fiber was 47.87%.[Conclusion] The bean curd residue in its palatability was enormously improved by SSF with Bacillus natto strain,which could be expected to be widely used as raw material of health foodstuff.展开更多
An experiment was performed to study the influence of polymer binders on the physical properties,and stability against a simulated rainfall,of a slope consisting of engineering spoil.Results showed that low polymer bi...An experiment was performed to study the influence of polymer binders on the physical properties,and stability against a simulated rainfall,of a slope consisting of engineering spoil.Results showed that low polymer binder concentrations(≤500g/m3) could enhance the air permeability and moisture-retaining capacity of the engineering spoil;however,adding more polymer binder made the hardness of the engineering spoil increase and then decline.With the increase of polymer binder concentrations,the surface(0-5cm) permeability of the engineering spoil decreased but the permeability of the lower layers(5-10cm) increased.Polymer binders might reduce runoff and sediment,but the effect becomes weaker with the increase of rainfall.The results of this study have significance for engineering practices.Further experiments are needed to study the effects of binders under other conditions,such as natural rainfall,different slopes,different rock types,different degrees and spoil weathering and different added material,and the chemical interaction between soil and polymer binders.展开更多
Nanometer Ni0.5Zn0.5Fe2O4 powders with spinel phase were prepared by the hydrothermal method using purified FeSO4 solution from sodium jarosite's slag as materials. The results show that the spinel phase of Ni0.5Zn0....Nanometer Ni0.5Zn0.5Fe2O4 powders with spinel phase were prepared by the hydrothermal method using purified FeSO4 solution from sodium jarosite's slag as materials. The results show that the spinel phase of Ni0.5Zn0.5Fe2O4 powders begins to form at a relatively low temperature (130 ℃) and a shorter holding time (1 h) when pH=8. The crystallization kinetics equation at 200℃ is ln[-ln(1-x)] =-0.78+0.951n t. The growth activation energy of Ni0.5Zn0.5Fe2O4 grains is 41.6 kJ/moL in hydrothermal synthesis process. With the increase of sintering temperature, the density and diameter shrinkage of ferrite circulus increase, whereas its pores decrease. The results of magnetic measurements show that saturation magnetic flux density Bs increases and the coercivity Hc decreases with the increase of their sintering temperature. Magnetic parameters of all the investigated samples satisfy the character demand of high Bs, low Br and low Hc of soft magnetic ferrite materials.展开更多
This paper describes a new method for producing TiCl4 by chloridizing materials of high content CaO and MgO, in which a combined fluidized bed is used as a reactor to avoid agglomeration between particles caused by mo...This paper describes a new method for producing TiCl4 by chloridizing materials of high content CaO and MgO, in which a combined fluidized bed is used as a reactor to avoid agglomeration between particles caused by molten CaCl2 and MgCl2. The combined fluidized bed consists of at least a riser tube and a semi-circulating fluidized bed. Two kinds of high titanium slag, in which the total mass content of CaO and MgO is 2.03% and 9.09% respectively, are employed to examine the anti-agglomeration effect and the conversion of the materials when the temperature ranges are between 923.15K and 1073.15K, gas apparent velocity 0.7--1.1m.s-1, and inlet amount of solid materials is 4.6-7.0kg·h^-1. It is found that the anti-agglomeration effect in the combined fluidized bed is satisfactory and the new method can achieve a TiCl4 production capacity of 14.0-75.4t·m^-2·d^-1 in relation to 25.0-- 40.0t·m^-2·d^-1 from the conventional bubble bed. Furthermore, low-temperature chloridization, for example, at 923K or 973K, can also be used to produce TiCl4 and avoid agglomeration.展开更多
In the near future, fresh water will be very difficult to get and scarce. It is said that in 2025 half of the mankind will live in the areas where fresh water is not enough. Also, UN and WMO (World Meteorological Org...In the near future, fresh water will be very difficult to get and scarce. It is said that in 2025 half of the mankind will live in the areas where fresh water is not enough. Also, UN and WMO (World Meteorological Organization) are predicting five billion people will be in short of even drinking water. Also, in the present, there are some areas where sea water or chloride contained sand are used as mixing water with or without intension. The authors believe that the possibilities of using sea water as mixing water in concrete should be investigated seriously. In this paper, the authors would like to show various possibilities of using sea water as mixing water in RC (reinforced concrete) members. The possibilities are shown as follows: (1) mixed with pozzolanic materials (Blast furnace slag powder, etc.) expecting to fix the free chloride ion; (2) Mixed with corrosion inhibitor; (3) reinforced with stainless steel or corrosion resistant reinforcement; and (4) used in very dry or submerged conditions.展开更多
基金Project(2013ZX0754-001)supported by China National Critical Project for Science and Technology on Water Pollution Prevention and Control
文摘Preparation of electronic grade manganese sulfate from ferromanganese slag, including grinding, leaching and purification, was studied. The impurities, such as Fe3+, Al3+, Ca2+, Mg2+, heavy metal ions and Na+, K+, were removed from leaching solution by neutralized-hydrolysis, fluorination precipitation, sulfuration precipitation and re-crystallization. Effects of pH of reaction, temperature and dosage of the different additives on removal rates of the metallic ions in leaching solution were investigated, and the suitable temperature, pH and the added amount of precipitating agent were obtained. The prepared manganese sulfate product, of which the mass fractions of Ca2+, Mg2+, Na+, K+ are all smaller than 0.005%, the mass fractions of Fe3+, Al3+ and heavy metal ions are smaller than 0.001%, and the mass fraction of Mn2+ is greater than 32%, can meet the demand of anode materials of lithium-ion batteries.
基金Supported by Innovation Funds of Jiangxi Academy of Agricultural Sciences(20141CBS003)Jiangxi Provincial Earmarked Fund for Agriculture Research System(JXARS-02)~~
文摘China is a big producer and consumer of tea. A huge amount of tea waste is produced in China every year, resulting in environmental pollution and enormous natural resources waste. From the perspective of utilization way, this pa- per summarized the research progresses in tea waste as a raw material for ex- tracting active ingredients and preparing absorbent, activated carbon, bio-organic fer- tilizer, animal feed and nutrients for edible fungi cultivation. In addition, the develop- ment trend of comprehensive utilization of tea waste was prospected. It is found that the comprehensive utilization of tea waste using a variety of techniques can im- prove the utilization efficiency of tea waste and reduce production costs. Finally, a simple and practical comprehensive utilization program was proposed to provide a reference for practical application.
基金The National Natural Science Foundation of China(No.51376003)
文摘A kind of industrial solid waste, i.e., carbide slag, was used as CaO precursor to synthesize CO2 sorbent. The highly reactive synthetic sorbent was prepared from carbide slag, aluminum nitrate hydrate and glycerol water solution by the combustion synthesis method. The results show that the synthetic sorbent exhibits a much higher CO2 capture capacity compared with carbide slag. The CO2 capture capacity and the carbonation conversion of the synthetic sorbent are 0. 38 g/g and 0. 70 after 50 cycles, which are 1.8 and 2. 1 times those of carbide slag. The average carbonation conversion and the CO2 capture efficiency of the synthetic sorbent are higher than those of carbide slag with the same sorbent flow ratios. The required sorbent flow ratios are lower for synthetic sorbent to achieve the same CO2 capture efficiency compared with carbide slag. With the same sorbent flow ratio and CO2 capture efficiency, the energy requirement in calciner for the synthetic sorbent is less than that for carbide slag.
基金Project(2008BAB34B01-1)supported by the National Key Technology R&D Program of China
文摘The reduction smelting process for cobalt recovery from converter slag of the Chambishi Copper Smelter in Zambia was studied. The effects of reducing agent dosage, smelting temperature and time and the addition of slag modifiers (CaO and TiO2) were investigated. In addition, the depleted slag and cobalt-bearing alloy were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Under the determined conditions, 94.02% Co, 95.76% Cu and less than 18% Fe in the converter slag were recovered. It was found that the main phases of depleted slag were fayalite and hercynite; and the cobalt-bearing alloy mainly contained metallic copper, Fe-Co-Cu alloys and a small amount of sulfide.
基金Project(2009GK2003)supported by the Natural Science Foundation of Hunan Province,China
文摘The oxidizing roasting process of carbon ferrochrome to prepare potassium chromate in the presence of potassium carbonate and air was investigated. The effects of reaction temperature, reaction time, mole ratio of potassium carbonate to carbon ferrochrome were studied, and thermodynamics and kinetics were also discussed. It was observed that the reaction temperature and reaction time had a significant influence on the roasting reaction of carbon ferrochrome. The reaction mechanism changed greatly as the temperature varied. A two-stage roasting process was favorable for the roasting reaction, and a chromium recovery rate of 97.06% was obtained through this two-stage roasting method. The chromium residue yielded from this method was only 1/3 of the product. Moreover, the component of Fe in the residue was as high as 55.04%. Therefore, it can be easily recovered to produce sponge iron, realizing complete detoxication and zero-emission of chromium residue.
基金supported by the "Energy Efficiency & Resources" of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No. 20125010100030-11-2-400)
文摘Preliminary study on concentration and separation of tin(Sn) from copper alloy dross by selective dissolution method was conducted. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution which could allow separation of tin from the copper alloy dross. The tin as H2SnO3(metastannic acid) phase was precipitated in the solution with centrifuging process and transformed to tin dioxide(SnO2) after drying process. The dried sample was heat-treated at low temperature and its phase characteristics, surface morphology and chemical composition were investigated.
基金Project(07dz12028) supported by the Science Program of Science and Technology Commission of Shanghai Municipality,China
文摘In 2008,around 596 000 t of aluminum dross was generated from secondary aluminum industry in China;however,it was not sufficiently recycled yet.Approximately 95% of the Al dross was land filled without innocent treatment.The purpose of this work is to investigate Al dross recycling by environmentally efficient and friendly methods.Two methods of Al dross recycling which could utilize Al dross efficiently were presented.High-quality aluminum-silicon alloys and brown fused alumina(BFA) were produced successfully by recycling Al dross.Then,life cycle assessment(LCA) was performed to evaluate environmental impact of two methods of Al dross recycling process.The results show that the two methods are reasonable and the average recovery rate of Al dross is up to 98%.As the LCA results indicate,they have some advantages such as less natural resource consumption and pollutant emissions,which efficiently relieves the burden on the environment in electrolytic aluminum and secondary aluminum industry.
基金Project supported by the Foundation for the Author of NationalExcellent Doctoral Dissertation of China (No. 200149)the NaturalScience Foundation of Zhejiang Province (No. R305078), China
文摘We report the adsorption of phosphate and discuss the mechanisms of phosphate removal from aqueous solution by burst furnace slag (BFS) and steel furnace slag (SFS). The results show that the adsorption of phosphate on the slag was rapid and the majority of adsorption was completed in 5~10 min. The adsorption capacity of phosphate by the slag was reduced dramatically by acid treatment. The relative contribution of adsorption to the total removal of phosphate was 26%~28%. Phosphate adsorption on BFS and SFS follows the Freundlich isotherm, with the related constants of k 6.372 and 1/n 1.739 for BFS, and of k 1.705 and 1/n 1.718 for SFS. The pH and Ca2+ concentration were decreased with the addition of phosphate, suggesting the formation of calcium phosphate precipitation. At pH 2.93 and 6.93, phosphate was desorbed by about 36%~43% and 9%~11%, respectively. These results indicate that the P adsorption on the slag is not completely reversible and that the bond between the slag particles and adsorbed phosphate is strong. The X-ray diffraction (XRD) patterns of BFS and SFS before and after phosphate adsorption verify the formation of phosphate salts (CaHPO4·2H2O) after adsorption process. We conclude that the removal of phosphate by BFS and SFS is related to the formation of phosphate calcium precipitation and the adsorption on hydroxylated oxides. The results show that BFS and SFS removed phosphate nearly 100%, indicating they are promising adsorbents for the phosphate removal in wastewater treatment and pollution control.
文摘Using seawater in concrete can be considered as one of the sustainable approaches in construction industry not only to save the freshwater resource but also to promote the use of abandoned seawater resource, especially in the construction at the uninhabited area close to the sea where the procurement of fresh water is difficult. In this study, durability against chloride attack of seawater mixed concrete with different replacement ratio of BFS (blast furnace slag) and FA (fly ash) is discussed and the life time until the occurrence of corrosion crack is evaluated. The results show that: (1) Chloride penetration rate of seawater mixed specimens with BFS and FA is lower than that of freshwater mixed OPC (ordinary Portland cement) specimens; (2) Oxygen permeability of seawater mixed specimens with BFS and FA is almost the same or lower than that of freshwater mixed OPC specimens; (3) Total life time (corrosion incubation period and propagation period) of seawater mixed specimens with BFS and FA is almost the same or only slightly shorter than that of freshwater mixed OPC specimens. From the results, it was confirmed that the usage of seawater in concrete mixing is feasible in concrete with the appropriate BFS and FA replacement ratio.
基金the National Natural Science Foundation of China(No.52004342)the Innovation-Driven Project of Central South University,China(No.150240015)the Natural Science Fund for Outstanding Young Scholar of Hunan Province,China(No.2021JJ20065).
文摘A direct production method of high-strength titanium alloy from upgraded titania slag(UGS)was developed.First,UGS was reduced into alloy powder with 1.3 wt.%oxygen using magnesium powder.Subsequently,the alloy powder was compacted at 600 MPa to produce a pellet.Lastly,the pellet was sintered to produce titanium alloy.The reduced powder was characterized,and the effect arising from the sintering temperature on the sintered density,compressive strength,microstructure,and hardness of the alloys was studied.The results showed that the density tended to increase with the temperature increasing from 900 to 1200℃,whereas the porosity decreased.A significant sintering densification was achieved at the temperature above 1100℃(98.65%at 1100℃ and 99.41%at 1200℃).At 1100℃,the hardness and compressive strength reached the maximal values of the alloy,HV 655.7 and 1563 MPa,respectively.
基金Projects(51574067,51904063)supported by the National Natural Science Foundation of ChinaProjects(N172503016,N172502005,N172506011)supported by Fundamental Research Funds for the Central Universities,ChinaProject(2018M640259)supported by China Postdoctoral Science Foundation
文摘The effects of MgO/Al2 O3 ratio on the viscous behaviors of MgO-Al2 O3-TiO2-CaO-SiO2 systems were investigated by the rotating cylinder method.Raman spectroscopy was used to analyze the structural characteristics of slag and Factsage 7.0 was adopted to demonstrate the liquidus temperature of slag.The results show that the viscosity and activation energy for viscous flow decrease when the MgO/Al2O3 ratio increases from 0.82 to 1.36.The break point temperature and liquidus temperature of slag initially decrease and subsequently increase.The complex viscous structures are gradually depolymerized to simple structural units.In conclusion,with the increase of MgO/Al2O3 ratio,the degree of polymerization of slag decreases,which improves the fluidity of slag.The variations of liquidus temperature of slag lead to the same changes of break point temperature.
基金This study was supported by the National Natural Science Foundation of China (No. 50874029) and the National Basic Research Program of China (No.2007CB613504). Thanks are due to X.L. Nan and B.Y. Ma for their assistance in language editing.
文摘With titanium-bearing blast furnace slag, ammonium sulfate, citric acid and potassium carbonate as raw materials to produce foliar fertilizer and Ca-S-Si compound fertilizer by means of heating process for the first time, which improved the solubility of the slag and converted the nutritional elements into such ones which are prone to be absorbed by plants. The effects of process conditions on dissolution rate of titanium were mainly analyzed through the orthogonal experiment. The results showed that the optimum synthesis process conditions of foliar fertilizer from the slag were 360 ℃ for 35 min, the mass ratio of ammonium sulfate and titanium-bearing blast furnace slag was 8:1. Under these conditions more than 80% of iron, titanium, magnesium and part of silicon in titanium-bearing blast furnace slag converted into water-soluble substances and existing in foliar fertilizer. Foliar fertilizer contained nitrogen, sulfur, potassium, iron, titanium, magnesium and silicon, and pH value of foliar fertilizer was 6. Ca-S-Si compound fertilizer mainly contained calcium silicate and calcium sulfate, which existed in the form of citric acid-soluble substance and slightly soluble substance, respectively.
文摘[Objective] The aim was to optimize the appropriate solid state fermentation(SSF)conditions.[Method] The optimization of solid state fermentation using a mixture substrate of bean curd residue and the marc with Bacillus natto was developed.[Result] The best fermentation condition optimized by the test of single factor and the orthogonal design respectively was mixing ratio of bean curd residue to marc 2∶1,substrate pH value 6,fermentation temperature 39 ℃,inoculum volume 10% and fermentation time 48 h.Under this optimized fermentation condition,the content of crude fiber in the substrate decreased from 107.8 mg/g before SSF to 56.2 mg/g after SSF,and the degeneration rate of crude fiber was 47.87%.[Conclusion] The bean curd residue in its palatability was enormously improved by SSF with Bacillus natto strain,which could be expected to be widely used as raw material of health foodstuff.
基金NSFC (National natural science foundation of China) for funding(Grant No. 30870467) this paper
文摘An experiment was performed to study the influence of polymer binders on the physical properties,and stability against a simulated rainfall,of a slope consisting of engineering spoil.Results showed that low polymer binder concentrations(≤500g/m3) could enhance the air permeability and moisture-retaining capacity of the engineering spoil;however,adding more polymer binder made the hardness of the engineering spoil increase and then decline.With the increase of polymer binder concentrations,the surface(0-5cm) permeability of the engineering spoil decreased but the permeability of the lower layers(5-10cm) increased.Polymer binders might reduce runoff and sediment,but the effect becomes weaker with the increase of rainfall.The results of this study have significance for engineering practices.Further experiments are needed to study the effects of binders under other conditions,such as natural rainfall,different slopes,different rock types,different degrees and spoil weathering and different added material,and the chemical interaction between soil and polymer binders.
基金Project(50204001) supported by the National Natural Science Foundation of China
文摘Nanometer Ni0.5Zn0.5Fe2O4 powders with spinel phase were prepared by the hydrothermal method using purified FeSO4 solution from sodium jarosite's slag as materials. The results show that the spinel phase of Ni0.5Zn0.5Fe2O4 powders begins to form at a relatively low temperature (130 ℃) and a shorter holding time (1 h) when pH=8. The crystallization kinetics equation at 200℃ is ln[-ln(1-x)] =-0.78+0.951n t. The growth activation energy of Ni0.5Zn0.5Fe2O4 grains is 41.6 kJ/moL in hydrothermal synthesis process. With the increase of sintering temperature, the density and diameter shrinkage of ferrite circulus increase, whereas its pores decrease. The results of magnetic measurements show that saturation magnetic flux density Bs increases and the coercivity Hc decreases with the increase of their sintering temperature. Magnetic parameters of all the investigated samples satisfy the character demand of high Bs, low Br and low Hc of soft magnetic ferrite materials.
基金Supported by the National Natural Science Foundation of China (No.20306030) and China Postdoctoral Science Foundation (No.2003033240).
文摘This paper describes a new method for producing TiCl4 by chloridizing materials of high content CaO and MgO, in which a combined fluidized bed is used as a reactor to avoid agglomeration between particles caused by molten CaCl2 and MgCl2. The combined fluidized bed consists of at least a riser tube and a semi-circulating fluidized bed. Two kinds of high titanium slag, in which the total mass content of CaO and MgO is 2.03% and 9.09% respectively, are employed to examine the anti-agglomeration effect and the conversion of the materials when the temperature ranges are between 923.15K and 1073.15K, gas apparent velocity 0.7--1.1m.s-1, and inlet amount of solid materials is 4.6-7.0kg·h^-1. It is found that the anti-agglomeration effect in the combined fluidized bed is satisfactory and the new method can achieve a TiCl4 production capacity of 14.0-75.4t·m^-2·d^-1 in relation to 25.0-- 40.0t·m^-2·d^-1 from the conventional bubble bed. Furthermore, low-temperature chloridization, for example, at 923K or 973K, can also be used to produce TiCl4 and avoid agglomeration.
文摘In the near future, fresh water will be very difficult to get and scarce. It is said that in 2025 half of the mankind will live in the areas where fresh water is not enough. Also, UN and WMO (World Meteorological Organization) are predicting five billion people will be in short of even drinking water. Also, in the present, there are some areas where sea water or chloride contained sand are used as mixing water with or without intension. The authors believe that the possibilities of using sea water as mixing water in concrete should be investigated seriously. In this paper, the authors would like to show various possibilities of using sea water as mixing water in RC (reinforced concrete) members. The possibilities are shown as follows: (1) mixed with pozzolanic materials (Blast furnace slag powder, etc.) expecting to fix the free chloride ion; (2) Mixed with corrosion inhibitor; (3) reinforced with stainless steel or corrosion resistant reinforcement; and (4) used in very dry or submerged conditions.