Determination of probable mechanism function and kinetic parameters is important to hydrometallurgical kinetics.In this work,the most probable mechanism function and kinetic parameters of gibbsite dissolution in NaOH ...Determination of probable mechanism function and kinetic parameters is important to hydrometallurgical kinetics.In this work,the most probable mechanism function and kinetic parameters of gibbsite dissolution in NaOH solution are studied.The sample,the mixture of synthetic gibbsite and sodium hydroxide solution,was scanned in high-pressure differential scanning calorimetry(DSC) equipment with the heating rate of 10 K·min-1. Integral equation and differential equation of non-isothermal kinetics were solved to fit the data related to DSC curve.According to the calculation results,the most probable mechanism function for pure synthetic gibbsite dissolution in sodium hydroxide solution is presented based on the optimum procedure in the database of the mechanism function.The apparent activation energy obtained is(75±1) kJ·mol-1,the frequency factor is 10 8±1mol·s-1,and the reaction is a second order reaction.展开更多
The values of GΘ,EΘ or pH from 110 to 160℃ were calculated and the relevant potential expressions were obtained.E-pH diagrams of ZnS-H2O system at oxygen partial pressure of 0.8 MPa,ionic activity of 1.0 and differ...The values of GΘ,EΘ or pH from 110 to 160℃ were calculated and the relevant potential expressions were obtained.E-pH diagrams of ZnS-H2O system at oxygen partial pressure of 0.8 MPa,ionic activity of 1.0 and different temperatures were drawn through thermodynamical calculation.With the temperature increasing,the stable regions of S and Zn(Ⅱ) in the E-pH diagrams become gradually larger,but the amplification decreases over 150℃.The impacts of leaching parameters,such as temperature,liquid to solid ratio,initial acidic concentration,leaching time,oxygen partial pressure and stirring speed on the leaching rate of Zn(Ⅱ) and conversion rate of S in the single factor of high pressure leaching experiment of ZnS in autoclave,were studied.The leaching residue was examined by X-ray fluorescence(XRF) chemical composition identification and X-ray diffraction(XRD) phase identification,and the content of the leaching solution was tested by inductively coupled plasma-atomic emission spectrometry(ICP).The experimental results indicate that the leaching rate of zinc increases from 60.05% to 97.85% and the conversion rate of sulfur increases from 38.90% to 80.92% with the temperature increasing from 110℃ to 150℃,5:1 of liquid-to-solid ratio,150 g/L of initial acidic concentration,120 min of leaching time,0.8 MPa of oxygen partial pressure,and 480 r/min of stirring speed,which tend to be stable over 150℃.The experimental results correspond with theoretical calculation.展开更多
Effects of particle size of the zinc sulfide concentrate,leaching temperature,solid-to-liquid ratio and additive amount on pressure acid leaching process of the zinc sulfide concentrate were studied.The results indica...Effects of particle size of the zinc sulfide concentrate,leaching temperature,solid-to-liquid ratio and additive amount on pressure acid leaching process of the zinc sulfide concentrate were studied.The results indicate that the additive can improve the reaction kinetics and the conversion rate.And sulfur can be successfully separated from the zinc sulfide concentrate as elemental sulfur.The reasonable experiment parameters are obtained as follows:the leaching temperature 150℃,oxygen partial pressure 1 MPa,additive amount 1%,solid-to-liquid ratio 1:4,leaching time 2 h,initial sulfuric acid concentration 15%,and particle size less than 44μm.Under the optimum conditions,the leaching rate of the zinc can reach 95%and the reduction rate of the sulfur can reach 90%.展开更多
Numerical simulation of enhanced fluid flow characteristics in a three-stage double-stirring extraction tank was conducted with the coupling of an Eulerian multiphase flow model and a Morsi-Alexander interphase drag f...Numerical simulation of enhanced fluid flow characteristics in a three-stage double-stirring extraction tank was conducted with the coupling of an Eulerian multiphase flow model and a Morsi-Alexander interphase drag force model. Results show that the addition of a stirring device into the settler can efficiently reduce the volume fraction of out-of-phase impurity in the outlet, and accelerate the settling separation of oil-water mixture. Such addition can also effectively break down the oil-water-wrapped liquid droplets coming from the mixer, inhibit reflux from the outlet, and improve the oil-water separation. The addition of a stirring device induces ignorable power consumption compared with that by the mixer, and can thus facilitate the commercialized promotion of this novel equipment.展开更多
Carbonation decomposition of hydrogarnet is a significant reaction of the calcification-carbonation new method for alumina production by using low-grade bauxite.In this work,non-isothermal decomposition kinetics of hy...Carbonation decomposition of hydrogarnet is a significant reaction of the calcification-carbonation new method for alumina production by using low-grade bauxite.In this work,non-isothermal decomposition kinetics of hydrogarnet in sodium carbonate solution was studied by high-pressure differential scanning calorimetry(HPDSC) at different heating rates of 2,5,8,10,15 and 20 K·min^(-1),respectively.The activation energy(E_α) was calculated with the help of isoconversional method(model-free),and the reaction mechanism was determined by the differential equation method.The calculated activation energy of this reaction was 115.66 kJ·mol^(-1).Furthermore,the mechanism for decomposition reaction is Avrami-Erofeev(n=1.5),and the decomposition process is diffusion-controlled.展开更多
The effects of magnetic field intensity,roasting temperature and roasting time on digestion rate and settling performance of bauxite with different iron contents were investigated systematically.The results indicate t...The effects of magnetic field intensity,roasting temperature and roasting time on digestion rate and settling performance of bauxite with different iron contents were investigated systematically.The results indicate that such magnetic treatment can profoundly change the microstructure and digestion performance of bauxite.For the two samples carrying different iron contents,phase transformation of the aluminum oxide phase proceeds faster in the high iron bauxite than the low one.The optimal pretreatment conditions of low iron bauxite are roasting temperature 550 °C and magnetic field intensity 6 T,while for high iron bauxite are 500 °C and 9 T.The digestion rate of alumina can reach 95% and 92% at digestion temperature of 190 °C and 250 °C.The settling performances of roasted ore by intense magnetic field after digestion are enhanced through pretreatment.展开更多
The effects of pyrolysis mode and pyrolysis parameters on Cl content in alumina were investigated, and the alumina products were characterized by XRD, SEM and ASAP. The experimental results indicate that the spray pyr...The effects of pyrolysis mode and pyrolysis parameters on Cl content in alumina were investigated, and the alumina products were characterized by XRD, SEM and ASAP. The experimental results indicate that the spray pyrolysis efficiency is higher than that of static pyrolysis process, and the reaction and evaporation process lead to a multi-plot state of the alumina products by spray pyrolysis. Aluminum phase starts to transform into γ-Al2O3 at spray pyrolysis temperature of 600 °C, which is about 200 °C lower than that of static pyrolysis process. The primary particle size of γ-Al2O3 product is 27.62 nm, and Cl content in alumina products is 0.38% at 800 °C for 20 min.展开更多
High ferrotitanium is used as a deoxidizer and alloying agent in steelmaking processes and is mainly produced using high-cost remelting processes.The thermite method is a simple and low-cost method for preparing low f...High ferrotitanium is used as a deoxidizer and alloying agent in steelmaking processes and is mainly produced using high-cost remelting processes.The thermite method is a simple and low-cost method for preparing low ferrotitanium.However,the high levels of S,Al,and O residues in the product severely restrict its applicability in the low-cost preparation of good-quality high ferrotitanium.In this study,a novel multistage deep reduction method for preparing high-quality high ferrotitanium is proposed,and the multistage desulfurization mechanism is systematically investigated.The results indicate that multistage desulfurization is an effective method for reducing the S content of high ferrotitanium prepared via the thermite method.During the strong desulfurization stage,Ti_(2)S reacts with CaO at the slag-metal interface and produces CaS.The S content decreases,while the O content increases,with the increase of CaO in the CaO-Al_(2)O_(3)-based slag.During the deep desulfurization,Ti_(2)S is deeply reduced by the Ca and produces CaS,thus further reducing the S content.The S content decreases with the incremental addition of Ca and can be reduced to 0.035 wt%after multistage desulfurization.展开更多
The new method of in-situ desulfurization with mechanical stirring of new type impellers was introduced, in which the bubble's dispersion and disintegration of magnesium vapor were the key to boosting the desulfuriza...The new method of in-situ desulfurization with mechanical stirring of new type impellers was introduced, in which the bubble's dispersion and disintegration of magnesium vapor were the key to boosting the desulfurization efficiency and increasing the utilization rate of magnesium. Effects of different new type of impellers on bubble dis persion and disintegration were studied through bubble image analysis, gas-liquid mass transfer, and power con- sumption levels of different impeller structures. The results showed that the sloped swept-back blade impeller-2 pro- duces optimal bubble's dispersion and disintegration, as well as higher volumetric mass transfer coefficient and CO2 gas utilization while consuming the least power. Numerical simulation result with Fluent software also showed that the sloped swept-back blade impeller-2 has higher turbulent kinetic energy and better velocity distribution than the other two impellers.展开更多
Abstract: The impeller blade structure for gas injection refining under mechanical stirring has been explored by water model experiments. A sloped swept-back blade impeller is'proposed for the purpose. The central p...Abstract: The impeller blade structure for gas injection refining under mechanical stirring has been explored by water model experiments. A sloped swept-back blade impeller is'proposed for the purpose. The central part of the impeller is disk- or plate-shaped, and the blades are fitted to the side of the disk or plate. In addition, a disk is put on the top side of the impeller blades. The impeller can strengthen the radial and downward flow between the blades and weaken the swirl flow in the zone above the impeller. These effects on flow phenomena are favorable for disintegration and wide dispersion of bubbles which are injected from a nozzle attached to the center of the underside of the impeller. In addition, the sloped swept-back impeller requires less power consumption. The impeller shaft should be placed away from the vessel center so as to disperse the injected bubbles widely in the bath under mechanical stirring even with unidi- rectional impeller rotation and without installing baffles. The number of gas holes in the nozzle and the direction of gas injection have a little effect on the bubble disintegration and dispersion in the bath. Highly efficient gas injection refining can be established under the conditions of proper impeller size, larger nozzle immersion depth, larger eccen- tricity and rotation speed of the impeller. The sloped swept back blade impeller can decrease the power consumption and vet improve the bubble disintegration and wide dist^ersion in the bath.展开更多
Ferrotitanium is used as a deoxidizer and alloying agent during steelmaking process,which has a high demand for sulfur control.Sulfur was introduced from raw materials in the process of producing ferrotitanium by ther...Ferrotitanium is used as a deoxidizer and alloying agent during steelmaking process,which has a high demand for sulfur control.Sulfur was introduced from raw materials in the process of producing ferrotitanium by thermite method,where CaO was used as fluxing agent.At the same time,CaO has a great desulfurization capability.Effects of CaO addition on the distribution of sulfur in high titanium ferroalloy prepared by thermite method were studied in this work.The equilibrium diagram of Ti-AlFe-S system was calculated by FactSage 6.4 software package with FactPS and FTmisc database.The alloy and slag samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),inductively coupled plasma atomic emission spectrometer(ICP-AES),X-ray fluorescence(XRF)and high-frequency infrared ray carbon sulfur analyzer.The result indicates that the sulfur in the alloy firstly exists in the form of liquid FeS,thereafter TiS(s)and eventually Ti2 S(s)during cooling.The sulfur is mainly distributed in the alloy,and only a small amount of sulfur remains in the slag.Moreover,it is noted that the sulfur in the alloy does not distribute homogeneously,and it exists in the form of solid solution phase,(Ti,Al,Fe)S.S content in the slag,the sulfur capacity of the slag and the sulfur distribution ratio(LS)all increase with the increment of CaO addition,while S content in alloys decreases.展开更多
The process of pressure leaching the converter vanadium slag with waste titanium dioxide without roasting was studied. Mineralogy analysis indicates that the con- verter vanadium slag contains mainly three mineral pha...The process of pressure leaching the converter vanadium slag with waste titanium dioxide without roasting was studied. Mineralogy analysis indicates that the con- verter vanadium slag contains mainly three mineral phases: magnetite, titanium magnetite, and silicate phase. Vana- dium is in combination with iron, titanium, manganese, aluminum, and silicon. The impacts of leaching tempera- ture, leaching time, stirring speed, liquid-to-solid ratio, and initial leaching agent concentration were investigated on the waste titanium dioxide leaching process. The results indi- cate that under the optimal conditions, the vanadium and the iron leaching rates are 96.85 % and 93.50 %, respectively, and the content of titanium is 12.6 % in the residue. The main mineral phases for the residues under the optimal operation conditions are quartz, ilmenite, anatase, and sili- cate phase, and the residues can be reused as the extraction of titanium raw materials for titanium dioxide production technology by the sulfate method.展开更多
High ferrotitanium prepared directly by the thermite method has a disadvantageously high O content(≥10 wt%)because of the short slag-metal separation time.In this study,CaO and CaF2 are added to the melt to improve t...High ferrotitanium prepared directly by the thermite method has a disadvantageously high O content(≥10 wt%)because of the short slag-metal separation time.In this study,CaO and CaF2 are added to the melt to improve the basicity of the slag and melt separation under heat preservation is performed to strengthen slag-metal separation.The thermodynamics of the step-by-step reduction process of TiO2 in the Ti-Al-Fe-Si-O system whose composition is close to the alloy after melt separation were calculated.Samples of alloys and slags before and after melt separation were systematically analyzed.The result indicates that the reaction that TiO is reduced by Al to Ti is the limited step in the reduction process of TiO2.The O content of the alloys slightly decreases with temperature from 1873 to 2023 K,which agrees with the changes in the law of deoxidation limit.It is mainly attributed to the movement of chemical reactions in the alloy melt at different temperatures and slag-metal interfacial reaction.The addition of Al2 O3-CaO-CaF2 slag and high temperature promote the removal of Al2 O3 and titanium suboxides.The minimum contents of O and Al in the alloy reach 1.84 wt% and 3.26 wt%,respectively.展开更多
Xanthated crosslinked chitosan(XCCS) resin prepared under microwave irradiation were used for adsorbing Au(Ⅲ) ions in hydrochloric acid medium.The influence of pH and temperature on the adsorption capacity of XCCS wa...Xanthated crosslinked chitosan(XCCS) resin prepared under microwave irradiation were used for adsorbing Au(Ⅲ) ions in hydrochloric acid medium.The influence of pH and temperature on the adsorption capacity of XCCS was investigated.The original XCCS and the loaded XCCS were characterized by scanning electron microscope(SEM) and X-ray diffraction(XRD),respectively.The results indicate that the XCCS has ability to adsorb Au(Ⅲ) ions and the maximum adsorption capacity of Au(Ⅲ) ions on XCCS is observed at pH 1 and 20℃.The data of batch adsorption tests are fitted to kinetic models and isotherm models,respectively.The kinetics of adsorption process is found to follow pseudo-second-order kinetic rate model,and equilibrium data agree very well with the Langmuir model.Thermodynamic calculation of the Au(Ⅲ) ions adsorption process indicates that the adsorption process is spontaneous and endothermic.展开更多
Based on the technique for preparing La Cl3 via direct pyrolysis of rare earth chloride solution, a jet pyrolysis reactor was designed and the intra-reactor temperature and chemical reactions were numerically simulate...Based on the technique for preparing La Cl3 via direct pyrolysis of rare earth chloride solution, a jet pyrolysis reactor was designed and the intra-reactor temperature and chemical reactions were numerically simulated using computational fluid dynamics(CFD) technique.The results show that the flow rate variation at the fuel inlet does not largely affect the temperature in the reactor, while the increase in external pressure at the material inlet rapidly decreases the average temperature, Venturi temperature, and outlet temperature. The CH4 and O2inside the reactor are combusted completely, and when the material inlet pressure is \90 Pa, the La Cl3 is fully pyrogenated. The contents of CO2, La2O3, and HCl fluctuate near the Venturi tube and finally stabilize. La2O3 content at the outlet is in a top-to-bottom gradient.展开更多
This paper investigates the changes of phase and apparent morphology under the combined effects of an intense magnetic field and temperature field.The effect of different roasting conditions on the digestion performan...This paper investigates the changes of phase and apparent morphology under the combined effects of an intense magnetic field and temperature field.The effect of different roasting conditions on the digestion performance of roasted ore is also studied.The results indicate that roasting pretreatment under high magnetic fields can change the microstructure and digestion performance of bauxite.The Al phase changed faster of high iron bauxite than that of low iron bauxite.The digestion performance of low iron bauxite improved significantly through roasting pretreatment in intense magnetic field. But the digestion performance of bauxite get worse with the iron content in bauxite increase,because the high iron content of bauxite lead the shielding effect of magnetic field and make the crystal structure of bauxite stably,the surface area or low iron bauxite increased obviously during pretreatment.The optimal pretreatment condition of low iron bauxite is roasting temperature of 550℃,roasting time of 60min and magnetic field intensity of 6T,while for the high iron is roasting temperature of 500℃,roasting time of 60min and magnetic field intensity of 9T.展开更多
基金Supported by the Research Fund for the Doctoral Program of Higher Education(20050145029)the Science and Technology Talents Fund for Excellent Youth of Liaoning Province(2005221012)
文摘Determination of probable mechanism function and kinetic parameters is important to hydrometallurgical kinetics.In this work,the most probable mechanism function and kinetic parameters of gibbsite dissolution in NaOH solution are studied.The sample,the mixture of synthetic gibbsite and sodium hydroxide solution,was scanned in high-pressure differential scanning calorimetry(DSC) equipment with the heating rate of 10 K·min-1. Integral equation and differential equation of non-isothermal kinetics were solved to fit the data related to DSC curve.According to the calculation results,the most probable mechanism function for pure synthetic gibbsite dissolution in sodium hydroxide solution is presented based on the optimum procedure in the database of the mechanism function.The apparent activation energy obtained is(75±1) kJ·mol-1,the frequency factor is 10 8±1mol·s-1,and the reaction is a second order reaction.
基金Project (2007CB613504) supported by the National Basic Research Program of ChinaProject(20050145029) supported by the PhD Programs Foundation of Ministry of Education of ChinaProject(2005221012) supported by the Science and Technology Talents Fund for Excellent Youth of Liaoning Province, China
文摘The values of GΘ,EΘ or pH from 110 to 160℃ were calculated and the relevant potential expressions were obtained.E-pH diagrams of ZnS-H2O system at oxygen partial pressure of 0.8 MPa,ionic activity of 1.0 and different temperatures were drawn through thermodynamical calculation.With the temperature increasing,the stable regions of S and Zn(Ⅱ) in the E-pH diagrams become gradually larger,but the amplification decreases over 150℃.The impacts of leaching parameters,such as temperature,liquid to solid ratio,initial acidic concentration,leaching time,oxygen partial pressure and stirring speed on the leaching rate of Zn(Ⅱ) and conversion rate of S in the single factor of high pressure leaching experiment of ZnS in autoclave,were studied.The leaching residue was examined by X-ray fluorescence(XRF) chemical composition identification and X-ray diffraction(XRD) phase identification,and the content of the leaching solution was tested by inductively coupled plasma-atomic emission spectrometry(ICP).The experimental results indicate that the leaching rate of zinc increases from 60.05% to 97.85% and the conversion rate of sulfur increases from 38.90% to 80.92% with the temperature increasing from 110℃ to 150℃,5:1 of liquid-to-solid ratio,150 g/L of initial acidic concentration,120 min of leaching time,0.8 MPa of oxygen partial pressure,and 480 r/min of stirring speed,which tend to be stable over 150℃.The experimental results correspond with theoretical calculation.
基金Project(20050145029)supported by the Research Fund for the Doctoral Program of Higher Education of ChinaProject(2005221012)supported by Science and Technology Talents Fund for Excellent Youth of Liaoning Province,China
文摘Effects of particle size of the zinc sulfide concentrate,leaching temperature,solid-to-liquid ratio and additive amount on pressure acid leaching process of the zinc sulfide concentrate were studied.The results indicate that the additive can improve the reaction kinetics and the conversion rate.And sulfur can be successfully separated from the zinc sulfide concentrate as elemental sulfur.The reasonable experiment parameters are obtained as follows:the leaching temperature 150℃,oxygen partial pressure 1 MPa,additive amount 1%,solid-to-liquid ratio 1:4,leaching time 2 h,initial sulfuric acid concentration 15%,and particle size less than 44μm.Under the optimum conditions,the leaching rate of the zinc can reach 95%and the reduction rate of the sulfur can reach 90%.
基金financially supported by the National 863 Plan(2010AA03A405and 2012AA062303)+4 种基金the National 973 Plan(2012CBA01205)the National Natural Science Foundation of China(U120227451204040)the National Science and Technology Support Program(2012BAE01B02)the Fundamental Research Funds for the Central Universities(N130702001 and N130607001)
文摘Numerical simulation of enhanced fluid flow characteristics in a three-stage double-stirring extraction tank was conducted with the coupling of an Eulerian multiphase flow model and a Morsi-Alexander interphase drag force model. Results show that the addition of a stirring device into the settler can efficiently reduce the volume fraction of out-of-phase impurity in the outlet, and accelerate the settling separation of oil-water mixture. Such addition can also effectively break down the oil-water-wrapped liquid droplets coming from the mixer, inhibit reflux from the outlet, and improve the oil-water separation. The addition of a stirring device induces ignorable power consumption compared with that by the mixer, and can thus facilitate the commercialized promotion of this novel equipment.
基金Supported by the Joint Funds of the National Natural Science Foundation of China(U1202274)the National Natural Science Foundation of China(51204040)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China(201200421100 11)the Doctor Start-up Foundation in Taiyuan University of Science and Technology(20142001)
文摘Carbonation decomposition of hydrogarnet is a significant reaction of the calcification-carbonation new method for alumina production by using low-grade bauxite.In this work,non-isothermal decomposition kinetics of hydrogarnet in sodium carbonate solution was studied by high-pressure differential scanning calorimetry(HPDSC) at different heating rates of 2,5,8,10,15 and 20 K·min^(-1),respectively.The activation energy(E_α) was calculated with the help of isoconversional method(model-free),and the reaction mechanism was determined by the differential equation method.The calculated activation energy of this reaction was 115.66 kJ·mol^(-1).Furthermore,the mechanism for decomposition reaction is Avrami-Erofeev(n=1.5),and the decomposition process is diffusion-controlled.
基金Projects(U1202274,51004033,51204040,50974035)supported by the National Natural Science Foundation of ChinaProjects(2010AA03A405,2012AA062303)supported by the National High Technology Research and Development Program(863 Prograam)of ChinaProject(N100302005)supported by the Fundamental Research Funds for the Central Universities,China
文摘The effects of magnetic field intensity,roasting temperature and roasting time on digestion rate and settling performance of bauxite with different iron contents were investigated systematically.The results indicate that such magnetic treatment can profoundly change the microstructure and digestion performance of bauxite.For the two samples carrying different iron contents,phase transformation of the aluminum oxide phase proceeds faster in the high iron bauxite than the low one.The optimal pretreatment conditions of low iron bauxite are roasting temperature 550 °C and magnetic field intensity 6 T,while for high iron bauxite are 500 °C and 9 T.The digestion rate of alumina can reach 95% and 92% at digestion temperature of 190 °C and 250 °C.The settling performances of roasted ore by intense magnetic field after digestion are enhanced through pretreatment.
基金Projects(U1202274,51004033,51204040)supported by the National Natural Science Foundation of ChinaProject(2012AA062303)supported by the National High Technology Research and Development Program of China+2 种基金Project(2012BAE01B02)supported by the National Science and Technology Support Program of ChinaProject(L2014096)supported by the Education Department of Liaoning Province,ChinaProject(N130702001)supported by the Fundamental Research Funds for the Central Universities,China
文摘The effects of pyrolysis mode and pyrolysis parameters on Cl content in alumina were investigated, and the alumina products were characterized by XRD, SEM and ASAP. The experimental results indicate that the spray pyrolysis efficiency is higher than that of static pyrolysis process, and the reaction and evaporation process lead to a multi-plot state of the alumina products by spray pyrolysis. Aluminum phase starts to transform into γ-Al2O3 at spray pyrolysis temperature of 600 °C, which is about 200 °C lower than that of static pyrolysis process. The primary particle size of γ-Al2O3 product is 27.62 nm, and Cl content in alumina products is 0.38% at 800 °C for 20 min.
基金financially supported by the Technology Program of Henan Province(No.202102210207)the National Key Research and Development Plan(No.2017YFB0305401)+2 种基金the National Natural Science Foundation of China(Nos.51422403 and 51774078)the Fundamental Research Funds for the Central Universities(Nos.N162505002,N172506009 and N170908001)the Key Science and Shenyang Science and Technology Project(No.17-500-8-01)。
文摘High ferrotitanium is used as a deoxidizer and alloying agent in steelmaking processes and is mainly produced using high-cost remelting processes.The thermite method is a simple and low-cost method for preparing low ferrotitanium.However,the high levels of S,Al,and O residues in the product severely restrict its applicability in the low-cost preparation of good-quality high ferrotitanium.In this study,a novel multistage deep reduction method for preparing high-quality high ferrotitanium is proposed,and the multistage desulfurization mechanism is systematically investigated.The results indicate that multistage desulfurization is an effective method for reducing the S content of high ferrotitanium prepared via the thermite method.During the strong desulfurization stage,Ti_(2)S reacts with CaO at the slag-metal interface and produces CaS.The S content decreases,while the O content increases,with the increase of CaO in the CaO-Al_(2)O_(3)-based slag.During the deep desulfurization,Ti_(2)S is deeply reduced by the Ca and produces CaS,thus further reducing the S content.The S content decreases with the incremental addition of Ca and can be reduced to 0.035 wt%after multistage desulfurization.
基金Item Sponsored by National Natural Science Foundation of China(50974035,51074047)High Technology Research and Development Program of China(2010AA03A405,2012AA062303)Innovation Team Project of Provincial Science and Technology of Liaoning Province of China(LT2010034)
文摘The new method of in-situ desulfurization with mechanical stirring of new type impellers was introduced, in which the bubble's dispersion and disintegration of magnesium vapor were the key to boosting the desulfurization efficiency and increasing the utilization rate of magnesium. Effects of different new type of impellers on bubble dis persion and disintegration were studied through bubble image analysis, gas-liquid mass transfer, and power con- sumption levels of different impeller structures. The results showed that the sloped swept-back blade impeller-2 pro- duces optimal bubble's dispersion and disintegration, as well as higher volumetric mass transfer coefficient and CO2 gas utilization while consuming the least power. Numerical simulation result with Fluent software also showed that the sloped swept-back blade impeller-2 has higher turbulent kinetic energy and better velocity distribution than the other two impellers.
基金Item Sponsored by National Natural Science Foundation of China(50974035,51074047)National High Technology Research and Development Program(863 Program)of China(2010AA03A405,2012AA062303)Innovation Team Project of Provincial Science and Technology of Liaoning Province of China(LT2010034)
文摘Abstract: The impeller blade structure for gas injection refining under mechanical stirring has been explored by water model experiments. A sloped swept-back blade impeller is'proposed for the purpose. The central part of the impeller is disk- or plate-shaped, and the blades are fitted to the side of the disk or plate. In addition, a disk is put on the top side of the impeller blades. The impeller can strengthen the radial and downward flow between the blades and weaken the swirl flow in the zone above the impeller. These effects on flow phenomena are favorable for disintegration and wide dispersion of bubbles which are injected from a nozzle attached to the center of the underside of the impeller. In addition, the sloped swept-back impeller requires less power consumption. The impeller shaft should be placed away from the vessel center so as to disperse the injected bubbles widely in the bath under mechanical stirring even with unidi- rectional impeller rotation and without installing baffles. The number of gas holes in the nozzle and the direction of gas injection have a little effect on the bubble disintegration and dispersion in the bath. Highly efficient gas injection refining can be established under the conditions of proper impeller size, larger nozzle immersion depth, larger eccen- tricity and rotation speed of the impeller. The sloped swept back blade impeller can decrease the power consumption and vet improve the bubble disintegration and wide dist^ersion in the bath.
基金financially supported by the National Natural Science Foundation of China(Nos.51422403 and51504064)the Fundamental Research Funds for the Central Universities(No.N162505002)the National Basic Research Program of China(No.2013CB632606)
文摘Ferrotitanium is used as a deoxidizer and alloying agent during steelmaking process,which has a high demand for sulfur control.Sulfur was introduced from raw materials in the process of producing ferrotitanium by thermite method,where CaO was used as fluxing agent.At the same time,CaO has a great desulfurization capability.Effects of CaO addition on the distribution of sulfur in high titanium ferroalloy prepared by thermite method were studied in this work.The equilibrium diagram of Ti-AlFe-S system was calculated by FactSage 6.4 software package with FactPS and FTmisc database.The alloy and slag samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),inductively coupled plasma atomic emission spectrometer(ICP-AES),X-ray fluorescence(XRF)and high-frequency infrared ray carbon sulfur analyzer.The result indicates that the sulfur in the alloy firstly exists in the form of liquid FeS,thereafter TiS(s)and eventually Ti2 S(s)during cooling.The sulfur is mainly distributed in the alloy,and only a small amount of sulfur remains in the slag.Moreover,it is noted that the sulfur in the alloy does not distribute homogeneously,and it exists in the form of solid solution phase,(Ti,Al,Fe)S.S content in the slag,the sulfur capacity of the slag and the sulfur distribution ratio(LS)all increase with the increment of CaO addition,while S content in alloys decreases.
基金financially supported by the Chinese National Programs for High Technology Research and Development(Nos.2010AA03A405 and 2012AA062303)the National Natural Science Foundation of China(Nos.U1202274,51004033,51204040,and 50974035)+2 种基金the National Science and Technology Support Program(No.2012BAE01B02)the Fundamental Research Funds for the Central Universities(No.N100302005)the Doctoral Fund Project(No.20120042110011)
文摘The process of pressure leaching the converter vanadium slag with waste titanium dioxide without roasting was studied. Mineralogy analysis indicates that the con- verter vanadium slag contains mainly three mineral phases: magnetite, titanium magnetite, and silicate phase. Vana- dium is in combination with iron, titanium, manganese, aluminum, and silicon. The impacts of leaching tempera- ture, leaching time, stirring speed, liquid-to-solid ratio, and initial leaching agent concentration were investigated on the waste titanium dioxide leaching process. The results indi- cate that under the optimal conditions, the vanadium and the iron leaching rates are 96.85 % and 93.50 %, respectively, and the content of titanium is 12.6 % in the residue. The main mineral phases for the residues under the optimal operation conditions are quartz, ilmenite, anatase, and sili- cate phase, and the residues can be reused as the extraction of titanium raw materials for titanium dioxide production technology by the sulfate method.
基金financially supported by the National Natural Science Foundation of China (Nos. 51422403, 51774078 and U1508217)the Fundamental Research Funds for the Central Universities (No. N162505002)
文摘High ferrotitanium prepared directly by the thermite method has a disadvantageously high O content(≥10 wt%)because of the short slag-metal separation time.In this study,CaO and CaF2 are added to the melt to improve the basicity of the slag and melt separation under heat preservation is performed to strengthen slag-metal separation.The thermodynamics of the step-by-step reduction process of TiO2 in the Ti-Al-Fe-Si-O system whose composition is close to the alloy after melt separation were calculated.Samples of alloys and slags before and after melt separation were systematically analyzed.The result indicates that the reaction that TiO is reduced by Al to Ti is the limited step in the reduction process of TiO2.The O content of the alloys slightly decreases with temperature from 1873 to 2023 K,which agrees with the changes in the law of deoxidation limit.It is mainly attributed to the movement of chemical reactions in the alloy melt at different temperatures and slag-metal interfacial reaction.The addition of Al2 O3-CaO-CaF2 slag and high temperature promote the removal of Al2 O3 and titanium suboxides.The minimum contents of O and Al in the alloy reach 1.84 wt% and 3.26 wt%,respectively.
基金financially supported by the National Natural Science Foundation of China(Nos.51004072,51004033,51074047)the National“Twelfth Five-Year”Plan for Science&Technology Support Program of China(No.2012BAE01B02)。
文摘Xanthated crosslinked chitosan(XCCS) resin prepared under microwave irradiation were used for adsorbing Au(Ⅲ) ions in hydrochloric acid medium.The influence of pH and temperature on the adsorption capacity of XCCS was investigated.The original XCCS and the loaded XCCS were characterized by scanning electron microscope(SEM) and X-ray diffraction(XRD),respectively.The results indicate that the XCCS has ability to adsorb Au(Ⅲ) ions and the maximum adsorption capacity of Au(Ⅲ) ions on XCCS is observed at pH 1 and 20℃.The data of batch adsorption tests are fitted to kinetic models and isotherm models,respectively.The kinetics of adsorption process is found to follow pseudo-second-order kinetic rate model,and equilibrium data agree very well with the Langmuir model.Thermodynamic calculation of the Au(Ⅲ) ions adsorption process indicates that the adsorption process is spontaneous and endothermic.
基金financially supported by the National Natural Science Foundation of China (Nos. 51204040 and U1202274)the National Science and Technology Support Program (No. 2012BAE01B02)the Fundamental Research Funds for the Central Universities (Nos. N130702001 and N130402012)
文摘Based on the technique for preparing La Cl3 via direct pyrolysis of rare earth chloride solution, a jet pyrolysis reactor was designed and the intra-reactor temperature and chemical reactions were numerically simulated using computational fluid dynamics(CFD) technique.The results show that the flow rate variation at the fuel inlet does not largely affect the temperature in the reactor, while the increase in external pressure at the material inlet rapidly decreases the average temperature, Venturi temperature, and outlet temperature. The CH4 and O2inside the reactor are combusted completely, and when the material inlet pressure is \90 Pa, the La Cl3 is fully pyrogenated. The contents of CO2, La2O3, and HCl fluctuate near the Venturi tube and finally stabilize. La2O3 content at the outlet is in a top-to-bottom gradient.
基金Item Sponsored by the Natural Science Foundation of China(NO.51004033,No.50934005,No.50974035,No.51074047)National 863 plan(2010AA03A405,2012AA061403)+1 种基金Operation expenses for universities'basic scientific research(N100302005)The doctoral fund of EDU gov(20050145029)
文摘This paper investigates the changes of phase and apparent morphology under the combined effects of an intense magnetic field and temperature field.The effect of different roasting conditions on the digestion performance of roasted ore is also studied.The results indicate that roasting pretreatment under high magnetic fields can change the microstructure and digestion performance of bauxite.The Al phase changed faster of high iron bauxite than that of low iron bauxite.The digestion performance of low iron bauxite improved significantly through roasting pretreatment in intense magnetic field. But the digestion performance of bauxite get worse with the iron content in bauxite increase,because the high iron content of bauxite lead the shielding effect of magnetic field and make the crystal structure of bauxite stably,the surface area or low iron bauxite increased obviously during pretreatment.The optimal pretreatment condition of low iron bauxite is roasting temperature of 550℃,roasting time of 60min and magnetic field intensity of 6T,while for the high iron is roasting temperature of 500℃,roasting time of 60min and magnetic field intensity of 9T.