含Ce2O3渣系作用浓度的计算模型

为研究精炼渣中Ce2O3的加入对渣中Al2O3活度的影响,根据炉渣结构离子与分子共存理论和相关相图,建立1500℃下Ce2O3-Al2O3和CaO-Al2O3-Ce2O3渣系作用浓度的计算模型,考察Ce2O3对Al2O3作用浓度的影响。结果表明：对于Ce2O3-Al2O3渣系,当Ce2O3的摩尔分数在0.49左右时,Ce2O3·Al2O3的作用浓度达到最大值0.90,使得Al2O3和Ce2O3的作用浓度均达到较低水平;对于CaO-Al2O3-Ce2O3渣系,模型所计算的Al2O3作用浓度与实测Al2O3活度的变化趋势一致,即Ce2O3含量一定时,随着w(CaO)/w(Al2O3)的增加,Al2O3的作用浓度降低;保持w(CaO)/w(Al2O3)不变,随着Ce2O3含量的增加,Al2O3的作用浓度降低。同时,由计算结果绘出CaO和Ce2O3的等作用浓度线。总之,精炼渣中添加一定量的Ce2O3能够有效地降低Al2O3的作用浓度,这能提高精炼过程中高质量洁净钢中Al2O3的去除速率和精炼渣的精炼效率。     

CaO-MnO-SiO2渣系的表面张力计算模型

基于熔渣结构离子与分子共存理论和Butler方程,建立了CaO-MnO-SiO2熔渣表面张力计算模型。模型利用纯组元的表面张力和摩尔体积以及熔渣中各组元表面相和体相中作用浓度(活度)可以计算出CaO-MnO-SiO2熔渣表面张力随熔渣成分、温度的变化规律。表面张力的计算结果与文献介绍的值吻合很好。计算了1773 K下CaO-MnO-SiO2渣系的等表面张力线,并进一步考察了炉渣成分对表面张力的影响。     

渣中BaO和TiO2在真空下对钢液氮含量的影响

为了研究钢包顶渣中BaO和TiO2在真空下对钢液中氮含量的影响,选用caO-SiO2-Al2O3碱性渣作为基础渣系.实验结果表明,真空下,渣系中的BaO和TiO2对钢液氮含量有较强的影响作用;向熔渣中同时添加BaO和TiO2配成的渣系对钢液脱氮作用强于它们单独加入渣中的渣系对钢液脱氮的作用.     

Nb_2O_5-MnO-SiO_2渣中Nb_2O_5和MnO活度的研究SCIEI

本文利用含NbFe液与Nb_2O_5-MnO-SiO_2渣之间平衡,在1828K温度下应用固体电解质浓差电池方法测定了Fe液中氧的活度,从而计算出渣中Nb_2O_5及MnO的活度,并绘制了Nb_2O_5-MnO-SiO_2三元系的等α_(Nb_2O_5)和等α_(MnO)图。     

42CrMoA曲轴钢中CaO-SiO2-Al2O3系夹杂物的塑性化控制

为了减少42CrMoA曲轴钢精炼过程中CaO-SiO2-Al2O3系夹杂物对其基体损伤的影响,利用Factsage软件计算了42CrMoA曲轴钢中CaO-SiO2-Al2O3系低熔点夹杂物的成分,并根据钢液-夹杂物,钢液-精炼渣之间的平衡,计算分析了CaO-SiO2-Al2O3系夹杂物控制在塑性区域内所需的钢液成分及对精炼渣的要求.结果表明:CaO-SiO2-Al2O3系夹杂物存在两个变形良好的控制区域.区域1对应的精炼渣成分由于碱度过低在生产中受到极大限制,区域2要求的精炼渣成分往往会发生偏离.建议向精炼渣中配加适量的CaF2和MgO,以将CaO-SiO2-Al2O3三元系夹杂物转变为四元或多元系夹杂物.     

基于最小Gibbs自由能原理的CaO-SiO2炉渣和Si-Ca金属两相体系平衡热力学模型

基于封闭平衡体系Gibbs自由能最小原理对精炼Si液中杂质Ca的炉渣金属体系建立热力学模型,由该热力学模型得到Si液中Ca的摩尔分数xCa与CaO-SiO2二元渣系CaO的摩尔分数xCaO的关系和文献报道的实验结果吻合良好,即0.3相似文献   

高炉型含钛炉渣中MnO对TiO_2还原的影响SCIEI

研究了高炉冶炼钒钛磁铁矿时Ti(C,N)的生成规律以及高钛渣中MnO对TiO_2的影响。结果表明,高钛渣中MnO对抑制TiO_2还原在渣-焦处作用不大,而主要在渣-铁处,渣中含MnO4％左右,碱度0.6—1.2能显著抑制Ti(C,N)的生成,(MnO)在一定条件下还能显著抑制(SiO_2)的还原,加速脱硫反应。     

中间包覆盖渣中B2O3和Al2O3对钢液氮含量的影响

常压下,选用CaO-SiO2-Al2O3碱性渣系作为基础渣系,通过改变渣中B2O3和Al2O3含量,来分析其对钢液氮含量的影响作用.通过对实验结果的分析得知,虽然渣中B2O3和Al2O3对钢液脱氮作用不太明显,但是,熔渣中B2O3和Al2O3对钢液都有较好的保护作用,可以较好地阻止大气中的氮气进入钢液中.     

CaF_2-CaO-Al_2O_3-MgO-SiO_2渣系表面张力计算模型

基于熔渣结构离子与分子共存理论和Butler方程,建立了CaF2-CaO-Al2O3-MgOSiO2熔渣表面张力计算模型。本模型利用纯组元的表面张力和摩尔体积以及熔渣中各组元表面相和体相中作用浓度(活度)可以计算出CaF2-CaO-Al2O3-MgO-SiO2熔渣表面张力随熔渣成分、温度的变化规律。将计算得到的表面张力值与文献实测值进行对比,计算结果与文献实测值吻合很好。进一步考察了炉渣成分对表面张力的影响,以期为电渣重熔法精炼铜铬合金过程渣系的控制提供理论参考。     

42CrMoA曲轴钢中SiO2-Al2O3-MnO系夹杂物的塑性化控制

为预测42CrMoA曲轴钢中SiO2-Al2O3-MnO系夹杂物具有良好塑性变形能力的成分控制范围,利用热力学计算软件Factsage对1873 K下42CrMoA曲轴钢钢液与SiO2-Al2O3-MnO系夹杂物间的平衡进行计算.结果表明:为得到塑性变形良好的SiO2-Al2O3-MnO系夹杂物,应控制SiO2-Al2O3-MnO三元系夹杂物中15wt％～60wt％SiO2,17wt％～75wt％MnO,Al2O3＜30％,ω(MnO)/ω(SiO2)值为0.28～5.与之平衡时钢液中酸溶铝[Al]s含量应小于2.50×10-4,溶解氧含量小于3×10-5.     

THERMODYNAMIC CALCULATION MODELS FOR TiO_2-BASED SLAG MELTS

1.IntroductionTheincreasingdemandsf0rlownitrogensteelproductsgiveriset0greatenthusiaJsmtouseTiO2-basedfluxfordenitrogeniZationofsteel[1-3].ManyexperimentscondrmedthatTi0z-basedslagshavehighernitridecaPacitiesandaPpeartobeonekind0fthemosteffectivefiuxesf0rdeIiltrogenization.Butasfarastherm0dynamicstudiesareconcerned,littleworkhasbeenreported0nthethermodynamiccalculationm0delsforTiO2-base'slags[4],especiallyf0rmulticomponentslagswithtitania-Inadditi0n,aJsaresultofusingvanadium-bearingtitani…     

CO还原CaO－SiO_2－Al_2O_3－Fe_tO渣系研究

研究了在１７２３Ｋ下ＣＯ还原ＣａＯ－ＳｉＯ_２－Ａ１_２Ｏ_３－Ｆｅ_ｔＯ渣系。根据ＣＯ_２红外分析仪测定的出口气体中ＣＯ_２浓度变化，计算了炉渣的表现还原速度常数Ｋ_ａ和还原速度常数Ｋ。结果表明，加入Ａｌ_２Ｏ_３，提高了ＣａＯ－ＳｉＯ_２－Ｆｅ_ｔＯ的Ｋ_ａ和Ｋ值；炉渣碱度不变时，随着Ｆｅ_ｔＯ含量的增加，Ｋ_ａ呈增加趋势，但Ｋ则呈抛物线趋势变化；当ＦｅＯ的光学碱度∧_ＦｅＯ为１．０或０．８７时，Ｋ_ａ随该四元渣系光学碱度的增加而线性增加，而Ｋ则呈递减趋势。用炉渣规则溶液模型计算了ＣａＯ－ＳｉＯ_２－Ａｌ_２Ｏ_３－Ｆｅ_ｔＯ四元渣系的Ｆｅ_ｔＯ活度ａ_Ｆｅ_ｔＯ。     

含B2O3渣系的热力学计算模型

根据炉渣结构的共存理论和相图，推导了ＣａＯＢ２Ｏ３和ＦｅＯＦｅ２Ｏ３Ｂ２Ｏ３渣系的热力学计算模型。结果表明：（１）理论计算的ＣａＯＢ２Ｏ３渣系的作用浓度ＮＣａＯ及ＮＢ２Ｏ３与实测的活度ａＣａＯ及ａＢ２Ｏ３一致；（２）理论计算的ＦｅＯＦｅ２Ｏ３Ｂ２Ｏ３渣系的氧化能力ＮＦｅｔＯ与实测的炉渣ＦｅｔＯ的活度值相符合。这说明本文提出的热力学计算模型是合理的。     

Calculating models of mass action concentrations for structural units or ion couples in RbCl-H2O binary system and RbCl-RbNO3-H2O ternary system

Thermodynamic models of calculating mass action concentrations for structural units or ion couples in RbCl-H2O binary and RbCl-RbNO3-H2O ternary strong electrolyte aqueous solutions were developed based on the ion and molecule coexistence theory at 298.15 K. A transformation coefficient is needed to compare the calculated mass action concentration and the reported activity because they are obtained at different standard states and concentration units. The results show that the transformation coefficients between the calculated mass action concentrations and the reported activities of the same structural units or ion couples in RbCl-H2O binary and RbCl-RbNO3-H2O ternary strong electrolyte aqueous solutions change in a very narrow range. The transformed mass action concentrations of structural units or ion couples in RbCl-H2O binary system are in good agreement with the reported activities. The transformed mass action concentrations of RbCl and RbNO3 in RbCl-RbNO3-H2O ternary solution are also in good agreement with the reported activities, aRbCl and , with different total ionic strengths as 0.01, 0.05, 0.1, 0.5, 1.0, 1.5, 2.0, 3.0 and 3.5 mol/kg, respectively. All those results mean the developed thermodynamic model of strong electrolyte aqueous solutions can reflect structural characteristics of RbCl-H2O binary and RbCl-RbNO3-H2O ternary strong electrolyte aqueous solutions and the mass action concentration also strictly follows the mass action law.     

KINETICS OF REDUCTION IRON OXIDE IN CaO-SiO_2-Al_2O_3-Fe_tO SLAGS WITH CARBON SATURATED IN MOLTEN IRON

1.IntroductionItisimportanttoinvestigatethekineticsofreductionofironoxideinslagswithcarbonsaturatedinmoltenironforunderstandingboththeslag-metalreactioninthehearthofblastfurnaceandthefinalreductionbehavioursofprereductionironorepelletscontainingcarboninironbathreactor.Theprevious.......h..sll--7]focusedtheirattentionsmainlyonthereductionrateofpureironoxideortheredlltionrateofironoxideinsimpleslags.Thoseresultsarenotconsistentwiththatoftilerealsituation.Throughanalyzinggascompositionattheoutlet…     

CO还原CaO—SiO2—FetO三元渣系的研究

在1723K进行了CO还原CaO—SiO_2-Fe_(t)O三元渣系的研究根据CO_2红外分析仪测定的出口气体中的CO_2浓度变化,计算了炉渣的表观还原速度常数K_(a)结果表明,K_(a)随炉渣中Fe_1O量增加呈抛物线变化;当炉渣碱度R<1.0,Fe_(t)O为50％和R为1.5,Fe_(t)O为70％时,K_(a)分别出现最小值用炉渣规则溶液模型可计算1723K时的CaO-SiO_2-Fe_tO三元渣系的Fe_1O活度值a_(Fe_1O)。     

CALCULATION OF NaCl-BaCl_2-SrCl_2 PHASE DIAGRAM

The mathematical formulas are given for calculating the partial molar thermodynamic proper-ties in a ternary system from its three corresponding binary systems based on the new ternarysymmetric model presented by the authors in the foregoing paper.Applying this model toNaCl-BaCl_2-SrCl_2 system,the phase diagram of which as well as some isothermal sectionshave been calculated.The devations of temperature between the calculated and experimen-tal diagrams are less than five degrees.     

ACTIVITIES OF CaO AND La_2O_3 IN LIQUID CaO-SiO_2-La_2O_3 SLAGS AND SLAG STRUCTURE

The activity of CaO and La_2O_3 in the liquid ternary slay CaO-SiO_2-La_2O_3 has 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 La_2O_3 changes slowlywhile the ratio of mole fraction.x_(CaO)/x_(SiO_2),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 slagB_2O_3-La_2O_3 saturated witlt solid La_2O_3 at three different temperatures,the relation betweenIgγ_(La)~0 and I/T is determined as follows:Igγ_(La)~0=-20400/T+11.37(1500-1600C)A random network model of molten silicate structure was applied to CaO-SiO_2-La2O_3.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 La_2O_3 areconsiderahly 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.     

Effect of B2O3 content on viscosity and structure of SiO2−MgO−FeO-based slag

The effect of B₂O₃ content on the viscosity of SiO₂?MgO?FeO-based molten slag system was investigated using the rotating cylinder method. The evolution process of the melt structure under different contents of B₂O₃ was comprehensively studied via FTIR spectroscopy and a model for calculating the degree of polymerization was developed. The results showed that the viscosity of the molten slag decreased with the addition of B₂O₃, which had a slight effect when its content exceeded 3 wt.%. As the addition of B₂O₃ increased from 0 to 4 wt.%, the break temperature of the slags decreased from 1152 to 1050 °C and the apparent activation energy decreased from 157.90 to 141.84 kJ/mol. The addition of B₂O₃ to the molten slag destroyed the chain silicate structure to form a more cyclic borosilicate structure. The Urbain model was improved to calculate the viscosity of the SiO₂?MgO?FeO-based slags, and the values were in good agreement with the experimentally measured values.