SOME ASPECTS OF THE THERMODYNAMICS OF MELTS

为了从二元系中两组元活度的测定值之比求得该两组元的活度值,导出了一个变通的 Gibbs-Duhem 方程式,并在 PbCl_2-SnCl_2,PbCl_2-CdCl_2,AgCl-CuCl,Cu_2S-FeS,PbO-BiO_(1.5),PbO-SbO_(1.5),CaO-CaF_2及 CaO-SiO_2-CaF_2等冶金熔体中得到应用.多年前所发展的从 Ag 和 Pb 二元相图求得两组元活度的方法已扩大到含有单个 AB 化合物的二元系.用这一方法已求得 In-Sb 和 Sn-Te 系中各组元的活度.在研究某些黑色冶金渣与金属间的平衡时,用一适当选择的非铁金属代替 Fe作为熔剂金属有助于克服某些实验上的困难.采用 Sn 或 Cu 与熔渣平衡研究了 CaO-SiO_2,CaO-Al_2O_3和 CaO-SiO_2-Al_2O_3体系.对 CaO-SiO_2二元系获得的数据可以认为具有足够的准确度来验证 Masson 模型的合理性.     

CaO-SiO2-TiO2-Al2O3-MgO炉渣中三价和四价Ti氧化物的氧化还原平衡

实验研究了ＣａＯ－ＳｉＯ２－Ａｌ２Ｏ３－ＭｇＯ炉渣在不同温度和氧分压下,三价和四价Ｔｉ氧化物间的氧化还原平衡。结果表明：在ωＣａＯωＳ〈２时,ωＴｉ＾４＋ωＴｉ＾４＋＋ωＴｉ＾３＋与ωＣａＯωＳｉＯ２近似呈线性关系,并可用ωＴｉ＾４＋ωＴｉ＾４＋＋ωＴｉ＾３＋来判断炉渣碱度;ｘＴｉ＾３＋ｘＴｉ＾４＋随全二氧化钛摩尔分数ｘＴｉＯ２,Ｔｏｔ的增大而增大;升高温度有利于渣中高价Ｔｉ氧化物的还原（ω为质量     

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。     

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   

ACTIVITY OF MnO IN LIQUID BLAST-FURNACE-TYPE SLAGS AND ITS RATE OF REDUCTION

本文报告了锰在银、铁,渣、铁及渣、银间的分配数据及高炉型渣中MnO活度的计算结果。从熔渣结构观点讨论了碱度,Al_2O_3,MgO及CaF_2对渣中MnO活度的影响。还报告了渣中MnO还原速率的测定结果,讨论了反应级数问题。最后,对实验结果在生产实际中的应用进行了讨论.     

Na2O对含MgO铝酸钙炉渣相变规律和氧化铝浸出性能的影响（英文）

采用向铝酸钙炉渣体系中添加Na2O的方法,降低或消除铝酸钙炉渣中MgO的负作用,并分析其影响机理。结果表明:当MgO含量为3%时,Na2O的添加量由0增加至4%后,炉渣的氧化铝浸出率由68.73%提高到80.86%。对含4%Na2O的样品进行XRD分析,发现四元化合物C20A13M3S3已消失。添加Na2O不能完全消除MgO对炉渣浸出性能的负作用。XRD和EDS分析结果表明,Na2O会进入12CaO·7Al2O3的晶格并促进其形成。     

Optimum composition of blast furnace slag as deduced from liquidus data for the quaternary system CaO-MgO-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-SiO<Subscript>2</Subscript>

On the basis of liquidus measurements in the system CaO-MgO-Al₂O₃-SiO₂ and previously published data, diagrams have been constructed at 5 pct Al₂O₃ intervals from 5 to 35 pct Al₂O₃. Liquidus temperatures and primary phase fields are shown. The optimum composition of a blast furnace slag for a given alumina content is indicated. At the optimum point, ordinary slags will be entirely liquid and will have maximum desulphurization potential and minimum viscosity. The relation of optimum composition of slags to the “plateau region” of the liquidus surface, and the application of these data on synthetic quaternary slags to actual slag compositions are discussed. Index of refraction of glasses is given as well as composition, temperature, and phase data for each mixture.     

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.     

熔渣无污染短路电化学还原分析

在可控氧流冶金理念指导下发展了熔渣无污染短路电化学还原新方法。分析了以氧离子导体作隔离膜时从氧化物熔渣中直接提取金属的电化学还原原理。利用电池等效电路,比较了熔渣在短路、开路条件下电化学还原时氧电流的特点,讨论了熔渣还原时影响氧电流的因素。结果表明:外电路短路、降低电路中总电阻、选用更强的还原剂或采用阴极合金化等措施可以增大氧离子电流,提高熔渣电化学还原速度。实验利用碳饱和铁液作还原剂,组成如下两种电池:石墨棒|[O]Fe C饱和|ZrO2(MgO)|FeO(slag)|铁棒;石墨棒|[O]Fe C饱和|ZrO2(MgO)|FeO(slag) Cu(l)||钼丝,从CaO-SiO2-Al2O3-FeO系熔渣中分别得到了纯铁和无碳铁合金。     

The Sulfide Capacity of Iron Oxide-Rich Slags

The relationship between the sulfide capacity of slags rich in iron oxide and the sulfur partition ratio between the metal and slag is strongly related to the slag’s iron oxide concentration. For slags containing little or no lime, this relationship is linear for a constant concentration of iron oxide in the slag. The effect of silica on changes in the sulfide capacity of slags rich in iron oxide is similar to that of basic steel-making slags, particularly at low activity of silica in slag.     

Interfacial tension and contact angle variations of SUS304 melt in contact with solid oxides and CaO-SiO2-Al2O3(CaF2) slags at 1470°C

Study on the interfacial properties of SUS304 melt in contact with pedestal oxides and also liquid slags of varying chemistry was carried out by using a combination of the sessile drop method and a X-ray fluoroscopic technique at 1470°C. Interfacial tension and contact angle were obtained directly from a numerical solution of the Young-laplace equation. Surface tension of SUS304 was found to be 1467 mN.m in Ar-atmosphere which was considerably lower than that of pure iron. This may be due to the existence of surface active elements such as (Cr, Ni and Mn etc. in SUS304. Interfacial tensions of SUS304 in contact with CaO-Sio₂-Al₂O₃(CaF₂) slags were in the range of 925 to 1 148 mN/m. The contact angle between SUS 304 and various pedestal was about 120° regardless of pedestal oxides. A1₂O₃. TiO₂ and SiO₂. Contact angles between SUS304 and the pedestal alumina coexisting with liquid CaO-SiO₂-Al₂O₃CaF₃) were in the range of 125° to 142°.     

Treating electroplating residues with thermal plasmas

A process for the treatment of sludge containing heavy metals generated in electroplating processes has been developed. The process is based on the use of a plasma system and allows the recovery of some of the metals contained in the sludge, while generating totally inert slags as by-products. Experiments performed for the treatment of zinc-rich residues (20% zinc) showed that zinc can be recovered in the process (metallic or oxide form) while generating both a ferrous slag containing heavy metals and a ceramic type of slag (originated from the silica and calcium oxide contained in the sludge). The two types of slags are inert and produced when treating any type of electroplating residues using the described technology; the slags can be sold to steelmakers (in the case of the metallic slag), used as bedroad fillers (in the case of the ceramic slag), or discarded without risks for the environment. Laboratory-scale tests have been conducted, and a pilot plant that is capable of treating up to 150 kg/h of electroplating residues has been built.     

Li2O对CaO基钢包渣系脱磷能力影响的热力学研究

渣金平衡实验表明Li2 O替代CaO基钢包渣系中等量CaO使渣系磷酸盐容量Cp提高。在此基础上进行钢液脱磷的工艺性实验 ,研究了Li2 O含量、渣系碱度及氧化性对渣系脱磷能力的影响 ,并给出了控制转炉钢液在钢包中回磷及钢包渣脱磷的渣系。     

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…     

电解烟气净化系统氧化铝中杂质的影响及对策探讨

电解烟气净化系统流程中氧化铝输送系统是决定整个净化系统净化效率及系统流程是否通畅的关键.本文对造成输送系统堵塞的原因进行了分析,并根据今年来的工程经验,针对性的提出一些避免渣壳形成的手段和减少渣壳对电解烟气净化系统构成影响的可行手段.     

MECHANISM AND KINETICS OF TRANSFORMATION OF ALUMINA INCLUSIONS BY CALCIUM TREATMENT

The basic mechanism and kinetics of the transformation process of alumina inclusions in steel was reported when calcium introduced into the steel by wire feeding orpowder injection. To clarify the mechanisms model, experiments were performed by studying reactions between AltOs and CaO in a laboratory furnace and by performing calcium treatments in an 8kg induction furnace for Al deoxidised melt. The phases formed during the reaction between Al2O3 and CaO were examined by SEM-EDS （scanning electron microscope-energy dispersive spectrometer）, and the reaction sequence of Al2O3=〉 CA6=〉 CA2 =〉 CA =〉 CAx（l） was discussed in term of the experimental observations. The kinetics of the reaction of calcium with alumina inclusions were simulated by immersing alumina plates in a Ca treated steel melt in the induction furnace. Results were compared with observations of real inclusion transformation. A kinetic model was proposed based on the results.     

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…     

A revised thermodynamic description of the Co-W-C system

A thermodynamic reassessment of the Co-W-C system is presented. New information on the liquid (L)+face-centered cubic (fcc)+graphite+WC and L+fcc+WC+M₆C equilibria has recently been published. Because these equilibria are very important for extrapolation to higher-order systems, the ternary system has been revised. A revision of the Co-W system also has been performed.     

EFFECT OF FeO_n ON PROPERTIES OF CONVERTER END SLAG (LOW P CONTENT)

从相图分析和岩相观察出发,对转炉(低磷)终渣的性质进行分析。在此基础上,用工业生产中氧气转炉出钢渣的数据,计算高温状态下的相平衡,并将计算结果加以数学处理,得到了FeO_n含量与经析出晶体(C_2S,C_3S,CaO)后的转炉(低磷)炉渣内所残存的液相量之间关系。论证了控制渣中FeO_n对转炉渣性质的重要性。对炉渣粘度、“化渣”概念、转炉造渣原则以及炉渣性质的研究等问题进行了讨论。     

THE DESULPHURIZATION OF MOLTEN SLAGS IN THE GASEOUS PHASE DURING TOP-BLOWN WITH AIR

利用空气顶吹研究熔渣的气态脫硫动力学,着重研究了熔渣∑FeO含量、j值[j=N_(Fe_2O_3)/(N_(Fe_2O_3)+N_(FeO))]、以及碱度对气态脫硫速度的影响.对气态脫硫反应的机理及反应速度的限制性环节作了分析和讨论.最后,对金属直接的气态脫硫、炉渣的气态脫硫和炉渣脫硫本身的矛盾、以及气态脫碗在转炉炼钢工艺上的应用问题进行了简要的讨论.