CaO-SiO2-FeO-P2O5渣系中各组元的活度计算

根据熔渣分子和离子共存理论,建立了CaO-SiO2-FeO-P2O5渣系的活度计算模型.利用该模型对渣中各组元的活度进行了计算,并分析了w(FeO)和w(CaO)/w(SiO2)对渣中组元活度的影响.结果表明,在1 300℃下,CaO-SiO2-FeO-P2O5渣系中活度较高的组元是FeO、CaO·SiO2、2CaO·SiO2和3FeO·P2O5.当w(FeO)小于15%时,随着w(FeO)的增加,渣中2CaO·SiO2和3FeO·P2O5的活度不断升高,3CaO·P2O5活度降低.当w(FeO)大于15%时,随着w(FeO)的增加,渣中2CaO·SiO2和3FeO·P2O5的活度逐渐降低,而FeO的活度则不断升高.当w(CaO)/w(SiO2)小于1.5时,2CaO·SiO2的活度随碱度的增大而升高,3FeO·P2O5的活度变化不大.当w(CaO)/w(SiO2)大于1.5时,随炉渣碱度的增大,2CaO·SiO2和3FeO·P2O5的活度降低,而3CaO·P2O5的活度升高.     

电熔再结合镁铬砖的精炼渣浸实验

用试样旋转法在1600℃下实验研究了CaO－SiO2－Al2O3－MgO－CaF2（3％）型精炼渣组成对电熔再结合镁铬砖的侵蚀影响．结合渣浸试样的电镜分析，结果表明，随渣碱度（CaO／SiO2）的增大，试样的侵蚀增加；碱度大于1．8时，试样在冷却过程中粉化．由于尖晶石保护层的生成，渣中Al2O3含量的增加能沽少侵蚀．随渣中MgO含量的增加，试样的侵蚀减少，在此基础上，讨论了对提高镁铬砖炉衬有利的炉外精炼造渣制度．     

白云鄂博铁精矿造块过程中含钾脉石与萤石的相互作用

通过对钾长石体系、钾长石-萤石体系及钾长石-萤石-CaO体系在内的含钾长石体系的高温焙烧过程的实验研究,确定了钾长石与萤石不同温度下相互作用的产物.研究结果表明,钾长石在1 090℃开始发生分解反应,生成白榴石(KAlSi2O6)和SiO2.钾长石中加入CaF2,900℃就已经发生钾长石的分解反应,1 060℃开始有硅铝酸盐的生成;钾长石中加入CaF2和CaO,体系中有硅铝酸盐生成,并在1 050℃开始生成枪晶石(3CaO· 2SiO2·CaF2),1 270℃有镁黄长石(2CaO·MgO·2SiO2)和铝黄长石(2CaO· Al2O3·SiO2);焙烧过程伴随有KF生成.     

高碱度LF合成精炼渣泡沫化性能研究

在实验室条件下采用钼丝挂渣法测量熔渣发泡高度,以相对发泡高度作为衡量指标,结合理论分析,系统研究了高碱度合成精炼渣的泡沫化性能．结果表明：熔渣相对发泡高度随着黏度的增大、表面张力和密度的减小而增大．在精炼渣成分一定时,随温度升高和吹气量增加,熔渣相对发泡高度都有先增加后降低的趋势．具有较好泡沫化性能的精炼渣组成范围是：ω（CaO）／ω（SiO2）为5--8,ω（Al2O3）=27％,ω（CaF2）为3％～6％,ω（MgO）=8％,ω（FeO）〈0．5％．     

助熔剂种类与配比对高磷铁水脱磷渣高温性能的影响

分别以CaF2和B2O3为助熔剂,在实验室条件下研究了助熔剂种类与配比对脱磷渣熔点的影响,并测定了脱磷渣在不同温度下的黏度值。结果表明,以CaF2为助熔剂时,在保证脱磷渣熔点较低和流动性较好的同时,为了减轻设备腐蚀和环境污染程度,脱磷渣中CaF2与CaO的质量分数比值以0.50为最佳;以B2O3作为助熔剂时,只有当脱磷渣中B2O3与CaO的质量分数比值达到0.16时,助熔效果才比较明显。     

高铝铁矿石球团在预还原过程中的热力学行为

应用物质吉布斯自由能函数法计算高铝铁矿石球团在预还原过程中所发生反应的ΔG,明确球团中物相在该过程中的热力学行为.热力学计算、分析结果表明:还原阶段产生的FeO最易与Al2O3反应生成FeO·Al2O3,其次与SiO2反应生成2FeO·SiO2,最后与SiO2反应生成FeO·SiO2·Al2O3置换2FeO·SiO2和FeO·SiO2中SiO2生成FeO·Al2O3的反应较之SiO2置换FeO·Al2O3中Al2O3的反应要容易得多.FeO.SiO2的还原反应趋势要强于FeO·Al2O3及2FeO.SiO2.     

保护渣组分对部分稳定氧化锆原料高温稳定性的影响

选择CaO稳定氧化锆、CaO—Y2O3复合稳定氧化锆、Y2O3稳定氧化锆和MgO稳定氧化锆原料为研究对象,借助x射线衍射仪和扫描电子显微镜分析Al2O3、SiO2、Fe3O4、MnO2及3种不同组分的结晶器保护渣对这些原料高温稳定性的影响。结果表明,部分稳定氧化锆原料的高温稳定性主要取决于其稳定剂与渣组分的反应程度;高碱度渣有利于保持部分稳定氧化锆原料的稳定性。     

P在非均相脱磷剂中分布的研究

用FACT sage软件对脱磷渣在脱磷温度下进行热力学计算,确定固液两相共存的组成成分.CaO-FetO-SiO2-P2O5渣的温度升到1 350℃,然后将渣淬火,并进行电子探针定量分析.在冷却期间,C2S和C3P的固溶体从液态渣中析出,并形成一个成分范围较宽的伪二元固溶体.当渣中存在Ca2SiO4时,有利于脱磷,随着P含量的增加,Ca2SiO4相中溶解的P越来越多.Ca2Fe2O5相中的磷含量受初始渣中磷含量的影响程度不大.磷酸三钙(C3P)溶解于Ca2SiO4相中,并且在渣中呈现为Ca7(PO4)2(SiO4)2固溶体.P的初始含量对P分配比有关,初始含量越大,分配比越大.     

渣系对Ar气保护电渣重熔Ni-Cr-Co基高温合金质量的影响

在500 kg保护气氛电渣炉中重熔Ni-Cr-Co合金,分别采用低CaF2高Al2O3高CaO的五元渣系(渣系A)和高CaF2低Al2O3低CaO的五元渣系(渣系B)进行电渣重熔试验.结果表明,采用两种渣系重熔Al、Ti烧损率均小于7.0%,铸锭头尾Al、Ti偏差均≤0.05%;两种渣系冶炼的合金[O]、[N]、[S]纯净度都较高,但采用渣系A电渣锭底部w[H]增加约2×10-6,采用渣系B冶炼的电渣锭底部基本不增氢;采用渣系B重熔的合金锭元素显微偏析程度较小.采用渣系A重熔的合金枝晶间有明显的Laves-δ及一次碳化物析出相,而采用渣系B重熔的合金只有一次碳化物析出相.     

1873 K下CaF2-MgO-CaO-Al2O3-SiO2渣系对H13模具钢的脱氧研究

本文根据热力学和动力学理论,结合实验室实验,研究了1873 K下CaF2-MgO-Al2O3-CaO-SiO2渣系成分对H13工具钢脱氧极限的影响.理论计算结果与实验结果基本一致.研究结果表明,[Si]-[O]反应为脱氧控制反应,随着炉渣碱度的增大,脱氧极限降低.当碱度为2.0时,脱氧极限最低.在碱度为2.0且CaF2...     

P2O5对转炉钢渣矿物结构的影响

依据实际转炉钢渣理化特性,以CaO-MgO-SiO2-Fe2O3四元渣系作为基础渣系,向该渣系中加入渣量1%～7%（质量分数）的P元素,使用SEM和EDS对合成渣系矿物结构进行表征与分析。结果表明：合成渣系主要由硅酸二钙、铁酸二钙及方镁石组成,其中磷元素主要以磷酸三钙的形式固溶于硅酸二钙中,在其他相中并未发现磷元素的存在;随着磷含量的增加,磷元素在硅酸二钙矿物中的含量随之增加,并可能出现独立的磷灰石相,这可为转炉钢渣在磷肥工业的应用研究提供参考。同时,由于磷加入量增多,CaO优先与[PO4]4-反应,早先存在的方镁石逐渐消失而溶入基质相。基质相2CaO·Fe2O3向CaO·MgO·Fe2O3发生转变,最后形成2MgO·Fe2O3,表明高磷含量有利于改善转炉钢渣的安定性能。     

不锈钢粉尘内配煤团块高温自还原过程中金属铁的聚集

用不锈钢生产中的高碱度二次粉尘制备内配煤团块,在高温下自还原获得含铬、镍的金属铁粒.研究影响铁粒聚集长大的因素.研究表明：（1）内配煤团块的渣相碱度（w（CaO）/w（SiO2））小于2.8时,还原产物冷却过程中渣相与金属铁粒才能自然分离.碱度越低,渣量越大,越不利于金属铁聚集长大;（2）提高内配碳比,渣相残碳量明显升高,渣中过量的碳阻碍金属相聚集长大;（3）提高还原温度,直接还原铁的海绵状结构解体,逐渐聚集成颗粒状金属铁.还原温度越高,越有利于金属铁的聚集长大     

Physical Property Influence on Foaming Index of Refining Slag

The foaming indexes of a group of refining slag were measured. The refining slag with better foaming ability was chosen,its composition (mass frachon in %) is CaO, 53.25, SiO2, 17.75, MgO, 9; Al2O3, 15 and CaF2, 5. The relationship between slag foaming index and physical properties of the slag was obtained by dimensional analysis, and the expression indicates that viscosity of slag is the most important factor which influences foamng index. The influence sequence of slap composition on foaming index was also obtained as follows: CaF2→MgO→Al2O3→ B (CaO/SiO2).     

含BaO,Na2O渣系渣钢间硫平衡研究

在钼丝炉上进行了含BaO,Na2O精炼渣系渣钢间流平衡实验。研究 结果表明,在传统精炼渣系中加入BaO,能够提高渣系的硫容量,Na2O对渣系的硫容量也有很大的影响,但稳定性不好。     

转炉渣用于铁水预处理脱磷剂的热力学分析

针对几种典型转炉渣的成分分析,由FeOn^-(CaO MgO MnO)-(SiO2 P2O5）等活度图回归出氧化铁和氧化钙的活度,以确定其有效浓度,并在此基础上制定了转炉渣替代部分典型脱磷剂的热力学配方模型。该模型在保持脱磷率不变的情况下,根据典型脱磷剂中石灰、烧结矿、萤石的比值,同时考虑萤石对转炉渣液相线的影响,计算出用转炉渣替代部分脱磷剂后的脱磷剂新配方。     

Activity model and its application in CaO-FeO-SiO2-MoO3 quarternary system

The activity model of CaO-FeO-SiO2-MoO3 quarternary system was established according to the coexistence theory of slag structure and the reduction thermodynamics of molybdenum oxide was discussed by applying this model. The activities of SiO2 and MoO3 decrease, while that of CaO increases with increasing the basicity of slag. Among SiC, [C] and [Si] reactants, the reducing capability of SiC is the strongest, while that of [C] is the poorest at a high temperature (about 1873 K). It is advantageous to increase the yield of molybdenum by increasing the content of [Si] or [C]. Controlling of basicity of slag can prevent the oxidation loss of molybdenum.     

Research on mold flux for hypo-peritectic steel at high casting speed

Mold fluxes having adaptable properties were developed in the laboratory to solve quality defects, such as depressions and longitudinal cracks when casting hypo-peritectic steel at high casting speed. Firstly, the effect of components on the high basicity mold flux properties was first studied using the orthogonal method. In the scope of the studied content, Li2O has the largest effect on the melting temperature, and the least effect on the viscosity; CaF2 has the largest effect on the viscosity, and the least effect on the melting temperature; Na2O and CaO/SiO2 have no obvious influence on the melting temperature and viscosity. Secondly, two powders (Z1 and Z6) have reasonable viscosity-temperature curves, higher solidification temperatures, and porous structure after solidification, but the crystal property of Z6 is worse than that of Z1, and thus Z1 is more suitable for continuous casting hypo-peritectic steel at high casting speed. Thirdly, a higher basicity of powder, a less free enthalpy of crystal compound, and a lower baffle energy are good for a higher tendentiousness of crystal.     

Vaporization behavior of lead from the FeO-CaO-SiO_2-Al_2O_3 slag system

Vaporization behavior (1163-1463 K) of lead in the slag system of FeO-CaO-SiO2-Al2O3 with CaCl2 was examined.A thermodynamic estimation with the principle of Gibbs free energy minimization showed that the major vapor species from the sample of the FeO-CaO-SiO2-AI203 system+PbO+CaCl2 were metallic Pb,PbC1,PbCl2,and FeC12,at the experimental temperature range.The experimental results show that the mole ratio of vaporized CI in lead chlorides to vaporized Pb,simply expressed as CI/Pb,decreases with increasing temperature.The larger CUPb means a larger ratio of gaseous PbCl2,since metallic Pb and PbCI vapors are formed in a similar reduction atmosphere.The evaporation is initially rapid and becomes steady after holding for 10 rain.Gaseous PbCI2 is mainly formed during the heating period,and at the holding stage,it reacts with FeO to produce gaseous FeCI2.With regard to slag composition,FeO content and basicity significantly affect the evaporation of lead.High FeO content and high basicity promotes the formation of metallic Pb and PbCI,whereas,it prohibits PbCl2 evaporation.     

亚稳态Bi2SiO5晶体的制备及析晶热力学分析

采用熔体冷却法制备了亚稳态Bi2SiO5硅酸铋晶体,利用XRD、SEM等表征分析了所制备Bi2SiO5多晶的晶型及形貌特征.通过系统在相平衡温度时的可逆相变过程,计算了析晶过程的ΔH、ΔS和ΔG.实验结果表明:组成中当摩尔比Bi2O3/SiO2为1∶1时,所生成的Bi2SiO5晶体在2h保温时间后仍没有发生晶型转变.所制备的单相Bi2SiO5晶粒呈现层状生长,且层与层之间呈现紧密生长.热力学分析表明:当温度T=T0-ΔT=973.15K时,ΔG=-7.478KJ<0,说明从基础熔体中析出Bi2SiO5的过程是自发进行的;同时,熔体中的分相有利于Bi2SiO5晶体的析出.