Based on the density functional theory,we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons.De...Based on the density functional theory,we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons.Descriptors including global softness,Fukui function,local softness and local mulliken charge were calculated at SVWN/DN~* level of DFT with PC Spartan Pro.Nucleophilicity and basicity of 28 selected compounds were classified based on intensity.BP algorithm of artificial neural network(ANN) was employed to study the relationship between the descriptors and nucleophilicity/basicity.Cross-validation was carried out to avoid the over-fitting in training of ANN.A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons.The results show that the prediction based on the network matches with the experimental results well.The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity.The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.展开更多
Based on the density functional theory, we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons. ...Based on the density functional theory, we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons. Descriptors including global softness, Fukui function, local softness and local mulliken charge were calculated at SVWN/DN＊ level of DFT with PC Spartan Pro. Nucleophilicity and basicity of 28 selected compounds were classified based on intensity. BP algorithm of artificial neural network （ANN） was employed to study the relationship between the descriptors and nucleophilicity/basicity. Cross-validation was carried out to avoid the over-fitting in training of ANN. A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons. The results show that the prediction based on the network matches with the experimental results well. The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity. The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.展开更多
During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a rest...During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.展开更多
The properties of direct reduced iron(DRI)smelting slag are important in the DRI melting process for molten iron production to ensure the slag-iron separation and quality of molten iron.The influence of binary basicit...The properties of direct reduced iron(DRI)smelting slag are important in the DRI melting process for molten iron production to ensure the slag-iron separation and quality of molten iron.The influence of binary basicity on the viscosity and sulfide capacity of CaO-SiO_(2)-MgO-Al_(2)O_(3)-FeO slag was investigated by the high-temperature experiments,structural analysis and thermodynamic calculation.The viscosity of the slag decreased rapidly with an increase in basicity from 0.4 to 0.8,and this trend became slow as the basicity further increased to 1.2.For the acidic slag with basicity of 0.4 and 0.6,the viscosity at 1500℃ was higher than 0.6 Pa s,which was harmful for the fluidity of slag melt.The slags with basicity of 0.8,1.0 and 1.2 at 1500℃ showed the low viscosity of less than 0.6 Pa s.For the basic slag with basicity of 1.0 and 1.2,the rapid precipitation of melilite led to the abrupt increase behavior of the viscosity,and the acidic slag showed the gentle temperature-viscosity curves.The Raman analysis revealed that the conversion from Q^(3) to Q^(2),Q^(1) and Q^(0) mainly occurred with the basicity increasing from 0.4 to 0.8,and the conversion from Q^(2) to Q^(1) and Q^(0) was dominant with further increase in basicity to 1.2,decreasing the degree of polymerization.The sulfide capacity was improved with the increasing basicity due to the increase in O^(2-)ions,and CaS could be formed dominantly for S^(2-)stabilization in present slag.The sulfur partition ratio was derived from sulfide capacity,and the values of sulfur partition ratio at basicity of 0.4 and 0.6 were much smaller than those at basicity of 0.8,1.0 and 1.2,indicating a weak desulfurization ability of the slag with a low basicity.展开更多
The semi-molten smelting process of a mixture of saprolitic and limonitic laterite ores was systematically investigated and the effect of slag basicity was deeply analyzed.The results indicate that the slag system can...The semi-molten smelting process of a mixture of saprolitic and limonitic laterite ores was systematically investigated and the effect of slag basicity was deeply analyzed.The results indicate that the slag system can be located in the liquidus region of low melting-point diopside(CaMgSi_(2)O_(6))when slag basicity is kept at 0.3 and limonitic laterite mass fraction is not less than 10%.When the reduction temperature,C/O mass ratio,limonitic laterite mass fraction and slag basicity are kept at the optimum values of 1300℃,0.86,20%and 0.3,respectively,ferronickel products with grades 6.42%Ni and 86.99%Fe are prepared.The recovery rates of Ni and Fe reach 88.60%and 72.25%,respectively.展开更多
Ni-rich layered oxide cathode materials such as LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NCM811)face poor interfacial stability and serious side reactions with sulfide solid-state electrolytes.This problem is thought to be exa...Ni-rich layered oxide cathode materials such as LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NCM811)face poor interfacial stability and serious side reactions with sulfide solid-state electrolytes.This problem is thought to be exacerbated by the gradually accumulated basicity of the surface with the Ni content increasing.Herein,the acidic Li_(3)PO_(4)coating layer on NCM811 particles is introduced by ball-milling approach to neutralize the basicity and aggrandize the interfacial stability.The tailored surface structure and components of NCM811 not only suppress the direct contact of cathode particles with sulfide solid-state electrolyte,but also facilitate electrochemical dynamics by driving the Li+migration across the interface and promoting the electron exchange.Thus,cells with Li_(3)PO_(4)coating layer yield 101.3 mAh g^(-1)specific capacity at 2.0 C and highly reversed discharging capacity after suffering from harsh work conditions.Additionally,the stable coating layer broadens the electrochemical windows of cells,delivering long cycle stability(>100 cycles 0.5 C).This contribution highlights the importance of basicity regulation of Ni-rich layered oxide cathode and offers a low-cost and effective approach to design the interfacial structures for the development of all solid-state batteries.展开更多
Basicity has an important effect on the sinter quality, especially for low-titanium vanadium-titanium sinter. The effect of basieity on sintering behavior of low-titanium vanadium-titanium mixture, and the transferenc...Basicity has an important effect on the sinter quality, especially for low-titanium vanadium-titanium sinter. The effect of basieity on sintering behavior of low-titanium vanadium-titanium mixture, and the transference and distribution of element in sintering process were researched by sinter pot test, mineralogical analysis, scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS） analysis. The results show that CaO preferentially reacts with TiO2, generating pervoskite, so that the total liquid phase content of the sinter is low. There is an increase in the perovskite concentration of the sinter with the basicity ranging from 1.9：1 to 2.7：1. With increasing the basicity, the calcium ferrite content increases slightly and then rises rapidly, while the silicate content decreases and the metallurgical property of the sinter is improved. As for the distribution of these elements in the sinter, Ti occurs mainly in perovskite, V occurs mainly in silicate, and Fe occurs mainly in magnetite and hematite. The most abundant occurrence of Ca and Si occurs in silicate and perovskite. With increasing the basicity, the contents of A1 and Mg increase in calcium ferrite, while they decrease in other minerals.展开更多
The effects of basicity and MgO content on the viscosity of SiO2-CaO-MgO-9wt%Al2O3 slags with basicity from 0.4 to 1.0 and MgO content from 13wt%to 19wt%were investigated using the rotating cylinder method. A correlat...The effects of basicity and MgO content on the viscosity of SiO2-CaO-MgO-9wt%Al2O3 slags with basicity from 0.4 to 1.0 and MgO content from 13wt%to 19wt%were investigated using the rotating cylinder method. A correlation between the viscosity and the slag structure was determined by Fourier transform infrared （FTIR） spectroscopy. It is indicated that the complex network structure of the slag melt is depolymerized into simpler network units with increasing basicity or MgO content, resulting in a continuous decrease in viscosity of the slag. The viscosity is strongly dependent on the combined action of basic oxide components in the slag. Under the present experimental conditions, increasing the basicity is found to be more effective than increasing the MgO content in decreasing the viscosity of the slag. At higher temperatures, the increase of basicity or MgO content does not appreciably decrease the viscosity of the slag, as it does at lower tem-peratures. The calculated activation energy of viscous flow is between 154 and 200 kJ＆#183;mol-1, which decreases with an increase in basicity from 0.4 to 1.0 at a fixed MgO content in the range of 13wt%to 19wt%.展开更多
Mass action concentration （activity） calculation model was used to analyze the variation rule of mass action concentrations of slag compositions with basicity changing, and the effect of basicity on deoxidation capa...Mass action concentration （activity） calculation model was used to analyze the variation rule of mass action concentrations of slag compositions with basicity changing, and the effect of basicity on deoxidation capability and control of spinel and globular inclusions was investigated theoretically. From the calculation and experimental results, it was found that with the increase of basicity, the mass action concentration of Al2O3 and SiO2 decreases, while the mass action concentration of FeO and MgO increases at first and then decreases.Slag basicity below 3 to 4 would help to control spinel inclusions formation, and higher basicity improves formation of globular inclusions. Slag with basicity under 2 can effectively control the formation of globular inclusions. Deoxidation capability of slag increases with the increase of basicity, and slag with basicity about 4 could almost reach the maximum deoxidation capability. In order to smelt low oxygen steel with globular inclusions controlled, refining slag basicity should be controlled at about 4.展开更多
Desulfurization performance with low binary basicity refining slag in 72 grade tire cord steel was calculated using FactSage and it is found that sulfur content in steel decreases with the increase of basicity of slag...Desulfurization performance with low binary basicity refining slag in 72 grade tire cord steel was calculated using FactSage and it is found that sulfur content in steel decreases with the increase of basicity of slag, MgO content in slag and slag/steel ratio while sulfur partition ratio between slag and steel increases gradually with the increase of basicity of slag as well as MgO content. Experiments were carried out and the results are of great agreements with theoretical calculation. Then industrial application tests were performed in a domestic plant and good results were achieved. Sulfur content in steel decreases gradually during refining process, as a result, sulfur content in the billets is controlled in the range of 0.007 1%-0.008 1%. Sulfur content in steel refined with slag basicity of 1.21 is lower than that of 1.02, while the plasticity of oxide compound inclusions is a little better controlled in low basicity heats. Using refining slag with basicity of 1.0-1.2 and MgO content of 5%-10% and reducing the slag takeover of LD are favorable for improving the desulfurization performance and the plasticity of inclusions during the industrial production.展开更多
In high speed continuous casting of peritectic steel slabs, mold fluxes with high basicity are required for less surface defect product. However, the basicity of remaining liquid slag film tends to decrease in casting...In high speed continuous casting of peritectic steel slabs, mold fluxes with high basicity are required for less surface defect product. However, the basicity of remaining liquid slag film tends to decrease in casting process because of the crystallization of 3CaO ·2SiO2 · CaF2. Thus, a way is put forward to improve mold fluxesr properties by raising the original basicity. In order to confirm the possibility of this method, the effect of rising original basicity on the properties of mold fluxes is discussed. Properties of high fluorine based mold fluxes with different basicities and contents of CaF2 , Na2 O, and MgO were measured, respectively. Then, properties of higher basicity mold fluxes were discussed and compared with traditional ones. The results show that increasing the basicity index can improve the melting and flow property of mold fluxes. With the increasing basicity, crystallization rate of mold fluxes increases obviously and crystallization temperature tends to decrease when the basicity exceeds 1.35. The method presen- ted before is proved as a potential way to resolve the contradiction between horizontal heat transfer controlling and solidified shell lubricating for peritectic steel slab casting. But further study on improving the flow property of liquid slag is needed. This work can be used to guide mold fluxes design for high speed continuous casting of peritectic steel slabs.展开更多
The desulfurization ability of refining slag with relative lower basicity （B） and Al2O3 content （B = 3.5-5.0; 20wt%-25wt% Al2O3） was studied. Firstly, the component activities and sulfide capacity （Cs） of the sl...The desulfurization ability of refining slag with relative lower basicity （B） and Al2O3 content （B = 3.5-5.0; 20wt%-25wt% Al2O3） was studied. Firstly, the component activities and sulfide capacity （Cs） of the slag were calculated. Then slag-metal equilibrium experiments were carried out to measure the equilibrium sulfur distribution （Ls）. Based on the laboratorial experiments, slag composition was optimized for a better desulfurization ability, which was verified by industrial trials in a steel plant. The obtained results indicated that an MgO-saturated CaO-Al2O3-SiO2-MgO system with the basicity of about 3.5-5.0 and the Al2O3 content in the range of 20wt%-25wt% has high activity of CaO （αCaO）, with no deterioration of Cs compared with conventional desulfurization slag. The measured Ls between high-strength low-alloyed （HSLA） steel and slag with a basicity of about 3.5 and an Al2O3 content of about 20wt% and between HSLA steel and slag with a basicity of about 5.0 and an Al2O3 content of about 25wt% is 350 and 275, respectively. The new slag with a basicity of about 3.5-5.0 and an Al2O3 content of about 20wt% has strong desulfurization ability. In particular, the key for high-efficiency desulfurization is to keep oxygen potential in the reaction system as low as possible, which was also verified by industrial trials.展开更多
The addition of silica to steelmaking slags to decrease the binary basicity can promote phosphate enrichment in quenched slag samples. In this study, we experimentally investigated phosphate enrichment behavior in CaO...The addition of silica to steelmaking slags to decrease the binary basicity can promote phosphate enrichment in quenched slag samples. In this study, we experimentally investigated phosphate enrichment behavior in CaO-SiO2-FeO-Fe203-P205 slags with a P205 content of 5.00% and the binary basicity B ranging from 1.0 to 2.0, where the （%Fe/O）/（%CaO） mass percentage ratio was maintained at 0.955. The experimental results are explained by the defined enrichment degree c, of solid solution 2CaO·SiO2-3CaO·P205 （C2S-C3P）, where R_C2S-C3P is a component of the developed ion and molecule coexistence theory （IMCT）-Ni model for calculating the mass action concentrations Ni of structural units in the slags on the basis of the IMCT. The asymmetrically inverse V-shaped relation be- tween phosphate enrichment and binary basicity B was observed to be correlated in the slags under applied two-stage cooling conditions. The maximum content of PROs in the C2S-C3P solid solution reached approximately 30.0% when the binary basicity B was controlled at 1.3.展开更多
A new model is proposed to estimate the density of molten slag, in which the temperature dependence of density is described by Arrhenius Law with the activation energy expressed as the linear function of optical basic...A new model is proposed to estimate the density of molten slag, in which the temperature dependence of density is described by Arrhenius Law with the activation energy expressed as the linear function of optical basicity. Successful applications to the density calculations of CaO-Al2 O3-SiO2 and Al2 O3-CaO-MgO-SiO2 slag systems show that this formula can give a good description of composition and temperature dependence of density for molten slags. It is also found that the ionic band percentage of M-O band in MOx oxide is the intrinsic origin of the phenomenon that the slag with a high optical basicity has a large sensitivity to temperature.展开更多
Baivumebo iron ore is special magnetite containing fluorine,kalium and sodium elements,and the main raw material for ironmaking of Baotou Iron and Steel（Group） Co.The effects of basicity and ratio of Al2O3 to SiO2（...Baivumebo iron ore is special magnetite containing fluorine,kalium and sodium elements,and the main raw material for ironmaking of Baotou Iron and Steel（Group） Co.The effects of basicity and ratio of Al2O3 to SiO2（A/S） on the formation of silico-ferrite of calcium and aluminium（SFCA） in Baivumebo low silica sinters were studied by means of mini-sintering,XPF-500 optical mineralogical microscope and CSS-88000 electronic universal testing machine.The results show that it is beneficial to the formation of complex calcium ferrite to enhance the basicity of Baivumebo low silica sinters.The acicular SFCA-I was increased with the enhancing basicity and reached the peak at basicity 2.8,then the columnar or platy SFCA formed and the bonding strength decreased.Alumina is beneficial to the formation of acicular complex calcium ferrite in Baivumebo low silica sinters.But the residual unfused Al2O3 reagent came into being when A/S was 0.35,while complex calcium ferrite still remained to be acicular.There is a common rule about mineralogy components affected by basicity and ratio of A/S,that is,SFCA is increasing accompanied with hematite and porosity reduced,but the content of glass phase is stable展开更多
Viscosity is an important physical property of blast furnace slags and has a great influence on blast furnace operations. Because of time consumption and difficulties encountered during high temperature experimental m...Viscosity is an important physical property of blast furnace slags and has a great influence on blast furnace operations. Because of time consumption and difficulties encountered during high temperature experimental measurement, viscosity data are also limited, so a rea-sonable and accurate estimation model is required to provide the data for controlling and optimizing the blast furnace process. In the present study a viscosity model was proposed for blast furnace slags. In the model the activation energy was calculated by the optical basicity cor-rected for cations required for the charge compensation of , and the temperature dependence was described by the Weymann-Frenkel equation. The estimated viscosity values of the CaO-Al2O3-SiO2, CaO-Al2O3-SiO2-MgO, and CaO-Al2O3-SiO2-MgO-TiO2 systems fit well with experiment data, with the mean deviation less than 25%.展开更多
The single influence of capillary porosity and coupling effects of absolute basicity and capillary porosity on concrete carbonation were investigated. The experimental results showed that carbonation rate of concrete ...The single influence of capillary porosity and coupling effects of absolute basicity and capillary porosity on concrete carbonation were investigated. The experimental results showed that carbonation rate of concrete at a given absolute basicity （AB） increased moderately with the increase of the porosity ranging from 6.2% to 9.25%, and increased rapidly with porosity from 9.25% to 12.8%.The coupling effect mainly embodied in disappeared mutation point of capillary porosity, and the distributing regions of carbonation depth were clearly partitioned in the coupling influence of absolute basicity and capillary porosity. A design method on carbonation related durability of concrete based on the coupling effects was proposed.展开更多
At low basicity and low temperature, the dephosphorization behavior and phosphorus distribution ratio(LP) between slag and molten steel in the double slag and remaining slag process were studied with a 180 t basic oxy...At low basicity and low temperature, the dephosphorization behavior and phosphorus distribution ratio(LP) between slag and molten steel in the double slag and remaining slag process were studied with a 180 t basic oxygen furnace industrial experiment.The dephosphorization slags with different basicities were quantitatively analyzed.At the lower basicity range of 0.9–2.59, both LP and dephosphorization ratio were increased as the basicity of dephosphorization slag increased.Dephosphorization slag consisted of dark gray P-rich, light gray liquid slag,and white Fe-rich phases.With increasing basicity, not only did the morphologies of different phases in the dephosphorization slag change greatly, but the area fractions and P2O5 content of the P-rich phase also increased.The transfer route of P during dephosphorization can be deduced as hot metal → liquid slag phase + Fe-rich phase → P-rich phase.展开更多
基金National Science & Technology Major Project of China(Grant No.2009ZX09501-002)National Natural Science Foundation of China(Grant No.20802006).
文摘Based on the density functional theory,we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons.Descriptors including global softness,Fukui function,local softness and local mulliken charge were calculated at SVWN/DN~* level of DFT with PC Spartan Pro.Nucleophilicity and basicity of 28 selected compounds were classified based on intensity.BP algorithm of artificial neural network(ANN) was employed to study the relationship between the descriptors and nucleophilicity/basicity.Cross-validation was carried out to avoid the over-fitting in training of ANN.A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons.The results show that the prediction based on the network matches with the experimental results well.The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity.The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.
基金Foundation items： National Science ＆ Technology Major Project of China （Grant No. 2009ZX09501-002）, National Natural Science Foundation of China （Grant No. 20802006）.
文摘Based on the density functional theory, we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons. Descriptors including global softness, Fukui function, local softness and local mulliken charge were calculated at SVWN/DN＊ level of DFT with PC Spartan Pro. Nucleophilicity and basicity of 28 selected compounds were classified based on intensity. BP algorithm of artificial neural network （ANN） was employed to study the relationship between the descriptors and nucleophilicity/basicity. Cross-validation was carried out to avoid the over-fitting in training of ANN. A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons. The results show that the prediction based on the network matches with the experimental results well. The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity. The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.
基金financially supported by the National Natural Science Foundation of China(Nos.52274315 and 52374320)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-22-011A1 and FRF-DF22-16)。
文摘During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.
基金the financial support from China Postdoctoral Science Foundation(2024M750177)National Natural Science Foundation of China(52474345)and Science and Technology Major Project of WuHan(2023020302020572).
文摘The properties of direct reduced iron(DRI)smelting slag are important in the DRI melting process for molten iron production to ensure the slag-iron separation and quality of molten iron.The influence of binary basicity on the viscosity and sulfide capacity of CaO-SiO_(2)-MgO-Al_(2)O_(3)-FeO slag was investigated by the high-temperature experiments,structural analysis and thermodynamic calculation.The viscosity of the slag decreased rapidly with an increase in basicity from 0.4 to 0.8,and this trend became slow as the basicity further increased to 1.2.For the acidic slag with basicity of 0.4 and 0.6,the viscosity at 1500℃ was higher than 0.6 Pa s,which was harmful for the fluidity of slag melt.The slags with basicity of 0.8,1.0 and 1.2 at 1500℃ showed the low viscosity of less than 0.6 Pa s.For the basic slag with basicity of 1.0 and 1.2,the rapid precipitation of melilite led to the abrupt increase behavior of the viscosity,and the acidic slag showed the gentle temperature-viscosity curves.The Raman analysis revealed that the conversion from Q^(3) to Q^(2),Q^(1) and Q^(0) mainly occurred with the basicity increasing from 0.4 to 0.8,and the conversion from Q^(2) to Q^(1) and Q^(0) was dominant with further increase in basicity to 1.2,decreasing the degree of polymerization.The sulfide capacity was improved with the increasing basicity due to the increase in O^(2-)ions,and CaS could be formed dominantly for S^(2-)stabilization in present slag.The sulfur partition ratio was derived from sulfide capacity,and the values of sulfur partition ratio at basicity of 0.4 and 0.6 were much smaller than those at basicity of 0.8,1.0 and 1.2,indicating a weak desulfurization ability of the slag with a low basicity.
基金supports from the National Key R&D Program of China(No.2022YFC3901404)the Natural Science Foundation of Chongqing,China(No.CSTB2023NSCQ-BHX0166)the Fundamental Research Funds for the Central Universities,China(No.2023CDJXY-016)are sincerely acknowledged.
文摘The semi-molten smelting process of a mixture of saprolitic and limonitic laterite ores was systematically investigated and the effect of slag basicity was deeply analyzed.The results indicate that the slag system can be located in the liquidus region of low melting-point diopside(CaMgSi_(2)O_(6))when slag basicity is kept at 0.3 and limonitic laterite mass fraction is not less than 10%.When the reduction temperature,C/O mass ratio,limonitic laterite mass fraction and slag basicity are kept at the optimum values of 1300℃,0.86,20%and 0.3,respectively,ferronickel products with grades 6.42%Ni and 86.99%Fe are prepared.The recovery rates of Ni and Fe reach 88.60%and 72.25%,respectively.
基金supported by the National Natural Science Foundation of China(22379121)the Shenzhen Foundation Research Fund(JCYJ20210324104412034)+1 种基金the Fundamental Research Funds for the Central Universities(G2024KY05103)the“Scientists+Engineers”Team in Qinchuangyuan of Shaanxi Province(2024QCY-KXJ-023)。
文摘Ni-rich layered oxide cathode materials such as LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NCM811)face poor interfacial stability and serious side reactions with sulfide solid-state electrolytes.This problem is thought to be exacerbated by the gradually accumulated basicity of the surface with the Ni content increasing.Herein,the acidic Li_(3)PO_(4)coating layer on NCM811 particles is introduced by ball-milling approach to neutralize the basicity and aggrandize the interfacial stability.The tailored surface structure and components of NCM811 not only suppress the direct contact of cathode particles with sulfide solid-state electrolyte,but also facilitate electrochemical dynamics by driving the Li+migration across the interface and promoting the electron exchange.Thus,cells with Li_(3)PO_(4)coating layer yield 101.3 mAh g^(-1)specific capacity at 2.0 C and highly reversed discharging capacity after suffering from harsh work conditions.Additionally,the stable coating layer broadens the electrochemical windows of cells,delivering long cycle stability(>100 cycles 0.5 C).This contribution highlights the importance of basicity regulation of Ni-rich layered oxide cathode and offers a low-cost and effective approach to design the interfacial structures for the development of all solid-state batteries.
基金Projects(2012AA062302,2012AA062304) supported by the National High Technology Research and Development Program of China(863 Program)Projects(51090384,51174051) supported by the National Natural Science Foundation of ChinaProject(2012DFR60210) supported by the International Cooperation of Ministry of China
文摘Basicity has an important effect on the sinter quality, especially for low-titanium vanadium-titanium sinter. The effect of basieity on sintering behavior of low-titanium vanadium-titanium mixture, and the transference and distribution of element in sintering process were researched by sinter pot test, mineralogical analysis, scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS） analysis. The results show that CaO preferentially reacts with TiO2, generating pervoskite, so that the total liquid phase content of the sinter is low. There is an increase in the perovskite concentration of the sinter with the basicity ranging from 1.9：1 to 2.7：1. With increasing the basicity, the calcium ferrite content increases slightly and then rises rapidly, while the silicate content decreases and the metallurgical property of the sinter is improved. As for the distribution of these elements in the sinter, Ti occurs mainly in perovskite, V occurs mainly in silicate, and Fe occurs mainly in magnetite and hematite. The most abundant occurrence of Ca and Si occurs in silicate and perovskite. With increasing the basicity, the contents of A1 and Mg increase in calcium ferrite, while they decrease in other minerals.
基金financially supported by the National Natural Science Foundation of China(No.51174148)
文摘The effects of basicity and MgO content on the viscosity of SiO2-CaO-MgO-9wt%Al2O3 slags with basicity from 0.4 to 1.0 and MgO content from 13wt%to 19wt%were investigated using the rotating cylinder method. A correlation between the viscosity and the slag structure was determined by Fourier transform infrared （FTIR） spectroscopy. It is indicated that the complex network structure of the slag melt is depolymerized into simpler network units with increasing basicity or MgO content, resulting in a continuous decrease in viscosity of the slag. The viscosity is strongly dependent on the combined action of basic oxide components in the slag. Under the present experimental conditions, increasing the basicity is found to be more effective than increasing the MgO content in decreasing the viscosity of the slag. At higher temperatures, the increase of basicity or MgO content does not appreciably decrease the viscosity of the slag, as it does at lower tem-peratures. The calculated activation energy of viscous flow is between 154 and 200 kJ＆#183;mol-1, which decreases with an increase in basicity from 0.4 to 1.0 at a fixed MgO content in the range of 13wt%to 19wt%.
基金Item Sponsored by National Natural Science Foundation of China(51134009)Fundamental Research Funds for Central Universities of China(N100102001)
文摘Mass action concentration （activity） calculation model was used to analyze the variation rule of mass action concentrations of slag compositions with basicity changing, and the effect of basicity on deoxidation capability and control of spinel and globular inclusions was investigated theoretically. From the calculation and experimental results, it was found that with the increase of basicity, the mass action concentration of Al2O3 and SiO2 decreases, while the mass action concentration of FeO and MgO increases at first and then decreases.Slag basicity below 3 to 4 would help to control spinel inclusions formation, and higher basicity improves formation of globular inclusions. Slag with basicity under 2 can effectively control the formation of globular inclusions. Deoxidation capability of slag increases with the increase of basicity, and slag with basicity about 4 could almost reach the maximum deoxidation capability. In order to smelt low oxygen steel with globular inclusions controlled, refining slag basicity should be controlled at about 4.
基金Item Sponsored by National Key Basic Research and Development Program of China(2010CB30806)Central South University Postdoctoral Funded Project of China(120961)
文摘Desulfurization performance with low binary basicity refining slag in 72 grade tire cord steel was calculated using FactSage and it is found that sulfur content in steel decreases with the increase of basicity of slag, MgO content in slag and slag/steel ratio while sulfur partition ratio between slag and steel increases gradually with the increase of basicity of slag as well as MgO content. Experiments were carried out and the results are of great agreements with theoretical calculation. Then industrial application tests were performed in a domestic plant and good results were achieved. Sulfur content in steel decreases gradually during refining process, as a result, sulfur content in the billets is controlled in the range of 0.007 1%-0.008 1%. Sulfur content in steel refined with slag basicity of 1.21 is lower than that of 1.02, while the plasticity of oxide compound inclusions is a little better controlled in low basicity heats. Using refining slag with basicity of 1.0-1.2 and MgO content of 5%-10% and reducing the slag takeover of LD are favorable for improving the desulfurization performance and the plasticity of inclusions during the industrial production.
基金Item Sponsored by National Natural Science Foundation of China(50904083)
文摘In high speed continuous casting of peritectic steel slabs, mold fluxes with high basicity are required for less surface defect product. However, the basicity of remaining liquid slag film tends to decrease in casting process because of the crystallization of 3CaO ·2SiO2 · CaF2. Thus, a way is put forward to improve mold fluxesr properties by raising the original basicity. In order to confirm the possibility of this method, the effect of rising original basicity on the properties of mold fluxes is discussed. Properties of high fluorine based mold fluxes with different basicities and contents of CaF2 , Na2 O, and MgO were measured, respectively. Then, properties of higher basicity mold fluxes were discussed and compared with traditional ones. The results show that increasing the basicity index can improve the melting and flow property of mold fluxes. With the increasing basicity, crystallization rate of mold fluxes increases obviously and crystallization temperature tends to decrease when the basicity exceeds 1.35. The method presen- ted before is proved as a potential way to resolve the contradiction between horizontal heat transfer controlling and solidified shell lubricating for peritectic steel slab casting. But further study on improving the flow property of liquid slag is needed. This work can be used to guide mold fluxes design for high speed continuous casting of peritectic steel slabs.
基金financially supported by the National Basic Research Program of China (No. 2010CB630806)the State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing (No. 41603015)
文摘The desulfurization ability of refining slag with relative lower basicity （B） and Al2O3 content （B = 3.5-5.0; 20wt%-25wt% Al2O3） was studied. Firstly, the component activities and sulfide capacity （Cs） of the slag were calculated. Then slag-metal equilibrium experiments were carried out to measure the equilibrium sulfur distribution （Ls）. Based on the laboratorial experiments, slag composition was optimized for a better desulfurization ability, which was verified by industrial trials in a steel plant. The obtained results indicated that an MgO-saturated CaO-Al2O3-SiO2-MgO system with the basicity of about 3.5-5.0 and the Al2O3 content in the range of 20wt%-25wt% has high activity of CaO （αCaO）, with no deterioration of Cs compared with conventional desulfurization slag. The measured Ls between high-strength low-alloyed （HSLA） steel and slag with a basicity of about 3.5 and an Al2O3 content of about 20wt% and between HSLA steel and slag with a basicity of about 5.0 and an Al2O3 content of about 25wt% is 350 and 275, respectively. The new slag with a basicity of about 3.5-5.0 and an Al2O3 content of about 20wt% has strong desulfurization ability. In particular, the key for high-efficiency desulfurization is to keep oxygen potential in the reaction system as low as possible, which was also verified by industrial trials.
基金financially supported by the National Basic Research Program of China (No. 2014CB643401)the National Natural Science Foundation of China (Nos. 51372019, 51174186, and 51072022)
文摘The addition of silica to steelmaking slags to decrease the binary basicity can promote phosphate enrichment in quenched slag samples. In this study, we experimentally investigated phosphate enrichment behavior in CaO-SiO2-FeO-Fe203-P205 slags with a P205 content of 5.00% and the binary basicity B ranging from 1.0 to 2.0, where the （%Fe/O）/（%CaO） mass percentage ratio was maintained at 0.955. The experimental results are explained by the defined enrichment degree c, of solid solution 2CaO·SiO2-3CaO·P205 （C2S-C3P）, where R_C2S-C3P is a component of the developed ion and molecule coexistence theory （IMCT）-Ni model for calculating the mass action concentrations Ni of structural units in the slags on the basis of the IMCT. The asymmetrically inverse V-shaped relation be- tween phosphate enrichment and binary basicity B was observed to be correlated in the slags under applied two-stage cooling conditions. The maximum content of PROs in the C2S-C3P solid solution reached approximately 30.0% when the binary basicity B was controlled at 1.3.
基金Item Sponsored by National Natural Science Foundation of China(50774004)
文摘A new model is proposed to estimate the density of molten slag, in which the temperature dependence of density is described by Arrhenius Law with the activation energy expressed as the linear function of optical basicity. Successful applications to the density calculations of CaO-Al2 O3-SiO2 and Al2 O3-CaO-MgO-SiO2 slag systems show that this formula can give a good description of composition and temperature dependence of density for molten slags. It is also found that the ionic band percentage of M-O band in MOx oxide is the intrinsic origin of the phenomenon that the slag with a high optical basicity has a large sensitivity to temperature.
基金Sponsored by Inner Mongolia Science Foundation of China(2009MS0702)
文摘Baivumebo iron ore is special magnetite containing fluorine,kalium and sodium elements,and the main raw material for ironmaking of Baotou Iron and Steel（Group） Co.The effects of basicity and ratio of Al2O3 to SiO2（A/S） on the formation of silico-ferrite of calcium and aluminium（SFCA） in Baivumebo low silica sinters were studied by means of mini-sintering,XPF-500 optical mineralogical microscope and CSS-88000 electronic universal testing machine.The results show that it is beneficial to the formation of complex calcium ferrite to enhance the basicity of Baivumebo low silica sinters.The acicular SFCA-I was increased with the enhancing basicity and reached the peak at basicity 2.8,then the columnar or platy SFCA formed and the bonding strength decreased.Alumina is beneficial to the formation of acicular complex calcium ferrite in Baivumebo low silica sinters.But the residual unfused Al2O3 reagent came into being when A/S was 0.35,while complex calcium ferrite still remained to be acicular.There is a common rule about mineralogy components affected by basicity and ratio of A/S,that is,SFCA is increasing accompanied with hematite and porosity reduced,but the content of glass phase is stable
基金supported by the National Natural Science Foundation of China (No.51090384)
文摘Viscosity is an important physical property of blast furnace slags and has a great influence on blast furnace operations. Because of time consumption and difficulties encountered during high temperature experimental measurement, viscosity data are also limited, so a rea-sonable and accurate estimation model is required to provide the data for controlling and optimizing the blast furnace process. In the present study a viscosity model was proposed for blast furnace slags. In the model the activation energy was calculated by the optical basicity cor-rected for cations required for the charge compensation of , and the temperature dependence was described by the Weymann-Frenkel equation. The estimated viscosity values of the CaO-Al2O3-SiO2, CaO-Al2O3-SiO2-MgO, and CaO-Al2O3-SiO2-MgO-TiO2 systems fit well with experiment data, with the mean deviation less than 25%.
基金Funded by the National Basic Research Program of China(No.2009CB623200)Nanjing Key Construction Project (No.7612005822)
文摘The single influence of capillary porosity and coupling effects of absolute basicity and capillary porosity on concrete carbonation were investigated. The experimental results showed that carbonation rate of concrete at a given absolute basicity （AB） increased moderately with the increase of the porosity ranging from 6.2% to 9.25%, and increased rapidly with porosity from 9.25% to 12.8%.The coupling effect mainly embodied in disappeared mutation point of capillary porosity, and the distributing regions of carbonation depth were clearly partitioned in the coupling influence of absolute basicity and capillary porosity. A design method on carbonation related durability of concrete based on the coupling effects was proposed.
基金financially supported by the National Natural Science Foundation of China (No.U1960202)。
文摘At low basicity and low temperature, the dephosphorization behavior and phosphorus distribution ratio(LP) between slag and molten steel in the double slag and remaining slag process were studied with a 180 t basic oxygen furnace industrial experiment.The dephosphorization slags with different basicities were quantitatively analyzed.At the lower basicity range of 0.9–2.59, both LP and dephosphorization ratio were increased as the basicity of dephosphorization slag increased.Dephosphorization slag consisted of dark gray P-rich, light gray liquid slag,and white Fe-rich phases.With increasing basicity, not only did the morphologies of different phases in the dephosphorization slag change greatly, but the area fractions and P2O5 content of the P-rich phase also increased.The transfer route of P during dephosphorization can be deduced as hot metal → liquid slag phase + Fe-rich phase → P-rich phase.
