实验研究了碳饱和铁液与 CaO-SiO_2-TiO_2((%TiO_2)<18)系熔渣间(TiO_2)的还原速度,同时考察了初渣碱度、温度对(TiO_2)还原速度的影响.研究结果表明:在本实验体系中,在初渣碱度 B=(%CaO)/(%SiO_2)=0.54～1.5范围内,随着碱度的升高,(...实验研究了碳饱和铁液与 CaO-SiO_2-TiO_2((%TiO_2)<18)系熔渣间(TiO_2)的还原速度,同时考察了初渣碱度、温度对(TiO_2)还原速度的影响.研究结果表明:在本实验体系中,在初渣碱度 B=(%CaO)/(%SiO_2)=0.54～1.5范围内,随着碱度的升高,(TiO_2)的还原速度加快,而温度的提高也能加快(TiO_2)的还原速度.建立了在该实验体系中(TiO_2)被铁液中的溶解碳还原的速度模型,模型考虑了还原反应产生的 CO 气泡逸出渣层时对渣层产生的环流作用,实验数据与模型计算结果符合程度较好.通过数学模拟,得到了该体系中(TiO_2)被铁液中的溶解碳还原的两个重要参数:表观反应速度常数和 Ti 在渣铁间的分配比.结果表明该体系中(TiO_2)的还原反应为表观二级反应,过程受渣中(Ti^(4+))的传质控制,表观反应速度常数随着渣碱度或温度的升高而增大,反应表观活化能为66.60kcal/mol.当碱度B<1.5时,Ti 在渣铁间的分配比(%Ti)/[%Ti]随着碱度的升高或温度的升高而降低.展开更多
The activity of CaO and LaOin the liquid ternary slay CaO-SiO-LaOhas been de-termined by equilibrating Sn with the slag phase in a graphite crucible under l arm of CO at1600C.The experimental results ,showed that the ...The activity of CaO and LaOin the liquid ternary slay CaO-SiO-LaOhas been de-termined by equilibrating Sn with the slag phase in a graphite crucible under l arm of CO at1600C.The experimental results ,showed that the activity of CaO and LaOchanges slowlywhile the ratio of mole fraction.x/x,is less than unit.hut varies sharply while the ra-rio increases from 1 to 1.2.In addition,by equilibrating Sn with the binary slagBO-LaOsaturated witlt solid LaOat three different temperatures,the relation betweenIgγ~0 and I/T is determined as follows:Igγ~0=-20400/T+11.37(1500-1600C)A random network model of molten silicate structure was applied to CaO-SiO-La2O.It was found that the experimentally determined activity-composition curve of CaO arequalitatively reproduced by the curves calculated with the model,but the curves of LaOareconsiderahly different from the calculated ones.It implies that the model used is over-simpli-fied and that the difference in interaction energy between the metal cations of different valenceand silicate anions should be considered.展开更多
The rate of reducing Fet O in CaO-SiO2-Al2O3-Fet O slags with carbon saturated in molten iron has been determined in a graphite crucible in the temperature range of 1673-1773K. The effects of temperature, slag basicit...The rate of reducing Fet O in CaO-SiO2-Al2O3-Fet O slags with carbon saturated in molten iron has been determined in a graphite crucible in the temperature range of 1673-1773K. The effects of temperature, slag basicity and FetO content on the reduction rate have also been discussed. Test results show that the reduction rate increases with increasing temperature or FEtO concentration in slags, and the reduction rate has a parabolic relation with the simple basicity or optical basicity of slag, the maximum reduction rate being observed at around CaO/SiO2=1.5 of molten slags. The reduction reaction order is 1. 73 or 1.80, and the reduction activation energy is 299.9 or 295.9 kJ/mol in regard to Fet O weight content or Fet O activity calculated by using regular solution model, respectively. The reduction rate of CaO-SiO2-Al2 O3-Fet O slags with carbon saturated in molten iron is in the range of 0.32-3.48 mol-O/cm2·s.展开更多
An attempt was made to use the Wilson equation to predict the thermodynamic properties of the FeO-CaO-SiO2 melts at 1673 and 1873K. The activities of component FeO in the ternary melts at a given temperature were foun...An attempt was made to use the Wilson equation to predict the thermodynamic properties of the FeO-CaO-SiO2 melts at 1673 and 1873K. The activities of component FeO in the ternary melts at a given temperature were found to be conveniently calculated from the equation only with related binary parameters at different temperatures.The predicted values are in agreement with the ternary experimental data.展开更多
The removal of boron impurity from metallurgical-grade silicon for solar cell application in slag system of CaO-SiO_2 is investigated.The experiments are conducted in an electromagnetic induction furnace which is used...The removal of boron impurity from metallurgical-grade silicon for solar cell application in slag system of CaO-SiO_2 is investigated.The experiments are conducted in an electromagnetic induction furnace which is used to heat. The distribution coefficient of boron(L_B)between slag and silicon phase is particularly examined in terms of the optical basicity of slag.With the increase of optical basicity,L_B increases to a local maximum value of 1.58 when the optical basicity is 0.71 after getting to the minimum value of 0.72 when the optical basicity is 0.56.In that above optical basicity of 0.71,L_B decrease sharply which indicates that increasing the basicity of slag is not always effective in boron removal from silicon.展开更多
The investigation results of the bonding structure of CaO-SiO2 slag by means of molecular dynamics simulation are presented. The characteristics of partial radial distribution function gij(r) are in good agreement wit...The investigation results of the bonding structure of CaO-SiO2 slag by means of molecular dynamics simulation are presented. The characteristics of partial radial distribution function gij(r) are in good agreement with the measurement of X-ray diffraction, and the variation of Qn with different SiO4 tetrahedra following the change of Xcao is consistent with the results of Raman spectroscopy, The partial vibrational density of states Fsi(ω) shows that two bands appear in the range of 636-737 cm-1 and 800? 200 cm-1 respectively which are also consistent with Raman spectroscopy.展开更多
During the smelting process of the high Al steels,the reaction between SiOin molten slag and dissolved aluminum in liquid steel always takes place.This aluminathermic reduction reaction will lead to the substitution o...During the smelting process of the high Al steels,the reaction between SiOin molten slag and dissolved aluminum in liquid steel always takes place.This aluminathermic reduction reaction will lead to the substitution of 1mol SiOfor 2/3mol AlO.Therefore,the investigations about the influence of the ratio of AlOto SiOon viscosity and structure changes of mould flux during this process are very necessary.The viscosity variation of CaO-SiO-AlO-CaFv2 melts was studied by changing compositions considering the aluminathermic reduction reaction.It was found that viscosity increased monotonously with gradually increasing the substitution extent.According to the Raman analysis,the substitution of AlOfor SiOleads to the decrease of non-bridging oxygen but the increase of bridging oxygen.Therefore,degree of polymerization and viscosity increase as the substitution extent increases.By comparing the measured viscosities with the model calculated values,it was found that both the recently developed Zhang′s model and Roboud model could describe the viscosity variation behavior of CaO-SiO-AlO-CaFmelts very well.展开更多
A thermochemical model based on the ion and molecule coexistence theory(IMCT)was developed to calculate thermodynamic data in the CaO-SiO_(2)-Al_(2)O_(3) slag system,considering the influential role of oxide activitie...A thermochemical model based on the ion and molecule coexistence theory(IMCT)was developed to calculate thermodynamic data in the CaO-SiO_(2)-Al_(2)O_(3) slag system,considering the influential role of oxide activities on the thermodynamic properties of slags.Using this model,iso-activity contours were obtained for oxide components CaO,SiO_(2) and Al2O3 in this system at temperatures of 1,873 K and 1,773 K.When compared with the IMCT model,it is found that the predicted activities of oxide components in the CaO-SiO_(2)-Al_(2)O_(3) system using the model developed in this study better matches experimental data from literature in terms of both trend and numerical value.Therefore,the model developed in this study can serve as a robust modeling tool for metallurgical processes,and the thermodynamic data predicted by this new model can be used to improve the metallurgical technology.展开更多
文摘实验研究了碳饱和铁液与 CaO-SiO_2-TiO_2((%TiO_2)<18)系熔渣间(TiO_2)的还原速度,同时考察了初渣碱度、温度对(TiO_2)还原速度的影响.研究结果表明:在本实验体系中,在初渣碱度 B=(%CaO)/(%SiO_2)=0.54～1.5范围内,随着碱度的升高,(TiO_2)的还原速度加快,而温度的提高也能加快(TiO_2)的还原速度.建立了在该实验体系中(TiO_2)被铁液中的溶解碳还原的速度模型,模型考虑了还原反应产生的 CO 气泡逸出渣层时对渣层产生的环流作用,实验数据与模型计算结果符合程度较好.通过数学模拟,得到了该体系中(TiO_2)被铁液中的溶解碳还原的两个重要参数:表观反应速度常数和 Ti 在渣铁间的分配比.结果表明该体系中(TiO_2)的还原反应为表观二级反应,过程受渣中(Ti^(4+))的传质控制,表观反应速度常数随着渣碱度或温度的升高而增大,反应表观活化能为66.60kcal/mol.当碱度B<1.5时,Ti 在渣铁间的分配比(%Ti)/[%Ti]随着碱度的升高或温度的升高而降低.
文摘The activity of CaO and LaOin the liquid ternary slay CaO-SiO-LaOhas been de-termined by equilibrating Sn with the slag phase in a graphite crucible under l arm of CO at1600C.The experimental results ,showed that the activity of CaO and LaOchanges slowlywhile the ratio of mole fraction.x/x,is less than unit.hut varies sharply while the ra-rio increases from 1 to 1.2.In addition,by equilibrating Sn with the binary slagBO-LaOsaturated witlt solid LaOat three different temperatures,the relation betweenIgγ~0 and I/T is determined as follows:Igγ~0=-20400/T+11.37(1500-1600C)A random network model of molten silicate structure was applied to CaO-SiO-La2O.It was found that the experimentally determined activity-composition curve of CaO arequalitatively reproduced by the curves calculated with the model,but the curves of LaOareconsiderahly different from the calculated ones.It implies that the model used is over-simpli-fied and that the difference in interaction energy between the metal cations of different valenceand silicate anions should be considered.
文摘The rate of reducing Fet O in CaO-SiO2-Al2O3-Fet O slags with carbon saturated in molten iron has been determined in a graphite crucible in the temperature range of 1673-1773K. The effects of temperature, slag basicity and FetO content on the reduction rate have also been discussed. Test results show that the reduction rate increases with increasing temperature or FEtO concentration in slags, and the reduction rate has a parabolic relation with the simple basicity or optical basicity of slag, the maximum reduction rate being observed at around CaO/SiO2=1.5 of molten slags. The reduction reaction order is 1. 73 or 1.80, and the reduction activation energy is 299.9 or 295.9 kJ/mol in regard to Fet O weight content or Fet O activity calculated by using regular solution model, respectively. The reduction rate of CaO-SiO2-Al2 O3-Fet O slags with carbon saturated in molten iron is in the range of 0.32-3.48 mol-O/cm2·s.
文摘An attempt was made to use the Wilson equation to predict the thermodynamic properties of the FeO-CaO-SiO2 melts at 1673 and 1873K. The activities of component FeO in the ternary melts at a given temperature were found to be conveniently calculated from the equation only with related binary parameters at different temperatures.The predicted values are in agreement with the ternary experimental data.
基金Item Sponsored by the National Natural Science Foundation of China[u1137601,51104080]
文摘The removal of boron impurity from metallurgical-grade silicon for solar cell application in slag system of CaO-SiO_2 is investigated.The experiments are conducted in an electromagnetic induction furnace which is used to heat. The distribution coefficient of boron(L_B)between slag and silicon phase is particularly examined in terms of the optical basicity of slag.With the increase of optical basicity,L_B increases to a local maximum value of 1.58 when the optical basicity is 0.71 after getting to the minimum value of 0.72 when the optical basicity is 0.56.In that above optical basicity of 0.71,L_B decrease sharply which indicates that increasing the basicity of slag is not always effective in boron removal from silicon.
基金Project supported by Shanghai Natural Science Foundation
文摘The investigation results of the bonding structure of CaO-SiO2 slag by means of molecular dynamics simulation are presented. The characteristics of partial radial distribution function gij(r) are in good agreement with the measurement of X-ray diffraction, and the variation of Qn with different SiO4 tetrahedra following the change of Xcao is consistent with the results of Raman spectroscopy, The partial vibrational density of states Fsi(ω) shows that two bands appear in the range of 636-737 cm-1 and 800? 200 cm-1 respectively which are also consistent with Raman spectroscopy.
基金Item Sponsored by National Natural Science Foundation of China(51304018,51174022,51474141)
文摘During the smelting process of the high Al steels,the reaction between SiOin molten slag and dissolved aluminum in liquid steel always takes place.This aluminathermic reduction reaction will lead to the substitution of 1mol SiOfor 2/3mol AlO.Therefore,the investigations about the influence of the ratio of AlOto SiOon viscosity and structure changes of mould flux during this process are very necessary.The viscosity variation of CaO-SiO-AlO-CaFv2 melts was studied by changing compositions considering the aluminathermic reduction reaction.It was found that viscosity increased monotonously with gradually increasing the substitution extent.According to the Raman analysis,the substitution of AlOfor SiOleads to the decrease of non-bridging oxygen but the increase of bridging oxygen.Therefore,degree of polymerization and viscosity increase as the substitution extent increases.By comparing the measured viscosities with the model calculated values,it was found that both the recently developed Zhang′s model and Roboud model could describe the viscosity variation behavior of CaO-SiO-AlO-CaFmelts very well.
基金This work was financially supported by the National Natural Science Foundation of China(NSFC 52175352).
文摘A thermochemical model based on the ion and molecule coexistence theory(IMCT)was developed to calculate thermodynamic data in the CaO-SiO_(2)-Al_(2)O_(3) slag system,considering the influential role of oxide activities on the thermodynamic properties of slags.Using this model,iso-activity contours were obtained for oxide components CaO,SiO_(2) and Al2O3 in this system at temperatures of 1,873 K and 1,773 K.When compared with the IMCT model,it is found that the predicted activities of oxide components in the CaO-SiO_(2)-Al_(2)O_(3) system using the model developed in this study better matches experimental data from literature in terms of both trend and numerical value.Therefore,the model developed in this study can serve as a robust modeling tool for metallurgical processes,and the thermodynamic data predicted by this new model can be used to improve the metallurgical technology.
