钢渣氧化改质过程中的物相分析与影响因素探究

现今的各种钢渣回收工艺中,存在着严重的铁元素浪费问题,文中提出用大自然中常见的空气,将钢渣中的含铁氧化物在钢渣自带高温的作用下进行氧化改质,以适合后续进行回收利用的工艺.本实验对反应过程中不同温度以及不同渣碱度变化时钢渣的结晶行为进行探讨,利用自行配制的常见六元系转炉钢渣,进行各种控制变量上的分析,进一步论证预测的合理性.其中,碱度、保温时间、保温温度等条件的变化均对钢渣的氧化改质过程有着一定的影响.     

钢渣的回收与利用

介绍钢渣冷却处理，从钢渣中回收金属的工艺流程，渣钢的循环使用及渣钢的其他用途，为钢铁企业回收和利用钢渣，提供参考。     

用碳热还原法从含钒钢渣回收含钒生铁

实验研究表明对于含钒2．65％钢渣,钒元素主要分布在RO相和Ca3SiO5相中;调节渣中（CaO／SiO2）=2,含V2O53．4％的合成渣,熔化缓冷后,钒主要固溶于Ca3SiO5相中;对于V2O5含量在4．7％-7．0％之间的钢渣,钒是以CaV2O6还是Fe—Mn—V—O固溶体形式存在主要取决于渣中铁氧化物的含量。在钒含量较低的钢渣中,由于含钒相的晶粒较小,很难将钒从其它组分中分离出来,但在1550～1600℃条件下,用碳热还原法可以有效地回收钢渣中的钒,得到被碳饱和的钒铁合金,利用渣在冷却过程中自动粉化现象,很容易实现渣和合金的分离。     

八钢着力推进固废综合利用工作

八钢在水渣、钢渣利用取得一些成效的基础上,着手系统推进整个固体废物综合利用工作。近年来,八钢高度重视固废综合利用工作,从水渣、钢渣利用做起,先后建立了先进的矿渣微粉、铜渣处理等生产线,对高炉水渣、炼钢钢渣进行回收利用,不仅有效回收铁元素,还变废为宝,生产新型建筑材料,经济效益与环保效益显著。在此基础上,八着手对高炉瓦斯灰、烧结机头灰、除尘灰、氧化铁皮、各种污泥等所有固体废物成分进行详细分析研究,策划制订对全部固废进行系统处理综合利用的方案,特别针对含锌固废回收利用的难题开展工作。     

国内外冶金渣显热回收

钢渣具有很高的温度(1450～1650℃),钢渣热焓约为1670MJ/t,属于高品质的余热资源,具有很高的回收价值。但目前,国内外冶金渣多以水淬法为主,热量无法回收利用。由于冶金渣用途很广,因此,熔渣能量的回收原则就是不仅要回收其余热资源,而且要便于炉渣的再利用,并且不产生环境污染。     

从净液渣中回收铜的生产实践及其改进

本文对湿法炼锌净液渣的综合回收铜的工艺流程选择、生产实践及其改进进行了介绍,经生产实践证明从净液渣中回收高附加值产品精镉和电铜是可行的.     

炼钢厂固体废弃物循环利用的效果分析

炼钢生产过程中,产生的固体废弃物主要有钢渣及除尘系统捕集的金属粉尘。含铁尘泥加工为冷固球团后,做为冷却剂在转炉冶炼过程中抵消富余热量;钢渣磁选后,钢渣大块、中块、粒钢、混合渣粉、铸余渣钢等可以直接回收作为金属料使用;铁含量只有2%的尾渣将其做为转炉调渣剂使用,替代部分石灰、白云石及萤石的消耗。文章重点分析了炼钢厂回收固废(除尘灰、钢渣)高效利用的效果。     

首秦资源类固废综合回收利用实践

主要论述了在大力推广钢铁企业绿色可持续发展的大背景下,首秦对厂内资源类固废回收利用的探索和实践。除小部分固废可直接回吃外,首秦通过厂内自建加工线进行加工回吃,实现了大部分固废的回收利用,提高了自消纳率,为企业创效的同时,也为环境作出了积极贡献。2013年以来资源类固废回吃比例达到72%,比2012年提高2.3%。高炉渣通过自建水渣超细磨工艺实现年产水渣微粉约60万t。钢渣通过自建钢渣处理生产线,对渣钢进行干磨深加工,精选出水磨豆钢及钢渣水磨粉两种产品分别返回炼钢和烧结回收利用。烧结和高炉无法自回收利用的烧结机头三电厂除尘灰、高炉布袋灰与炼钢OG泥、氧化铁皮等固废配加一定燃料和皂土烧成红泥砖,烧成砖后破碎成一定粒度,返回炼钢作为冷却剂使用,破碎后的粉末返回烧结使用,后期该工艺改? ＡЫ豪涔糖蛲殴ひ眨档图庸し?0元/t。     

邯钢钢渣深处理现状及生产应用

介绍了邯钢钢渣预处理工艺的现状,并对钢渣深处理与综合利用生产线的工艺进行了阐述。该生产线采用干法生产,具有高效可控的渣铁分离技术,能充分回收钢渣中的铁元素,延伸加工利用尾渣,实现了钢渣的回收利用由无害化向高值化转变。     

粒化钢渣相变传热过程数值模拟

通过建立球形熔渣凝固过程的物理和数学模型,利用现代CFD设计软件FLUENT对不同粒径渣粒的凝固过程进行了数值模拟,得到了凝固过程中渣粒和周围气体的温度场,从而确定了渣粒完全凝固的时间,为熔渣粒化和余热回收设备的设计提供了理论基础。结果表明:渣粒初始温度1 823 K,渣粒直径为1~3 mm,冷却气体温度为373 K,冷却气体流速为1~20 m/s时,液态钢渣相变过程在2 s内释放出80%以上的热量。说明在氮气冷却条件下,只要保证一定的冷却时间,即可保证钢渣余热回收。     

高炉渣对钢渣改性的物理化学基础研究

钢渣用作建筑材料时,由于其中含有大量游离氧化钙(f-CaO),稳定性较差,通常需要改性钢渣以提高其稳定性、胶凝性. 在对钢渣、高炉渣进行化学成分和矿物组成分析的基础上,对高炉渣改性钢渣的可能性进行了热力学计算,结果表明高炉渣中的SiO₂与钢渣中f-CaO反应,生成胶凝相,同时降低了钢渣中的f-CaO含量. 本文通过研究热态高炉渣改性钢渣,结合X射线衍射、拉曼光谱、扫描电镜及能谱分析等研究方法,对改性钢渣的矿物成分、f-CaO含量、黏度变化等进行了分析. 研究发现随着热态高炉渣配比量的增加,改性渣黏度缓慢增加,改性钢渣中f-CaO、RO相含量降低,改性渣的胶凝性能提高. 在1550℃下,钢渣中添加10%高炉渣时,改性渣中2CaO·SiO₂(C₂S)、3CaO·SiO₂(C₃S)含量显著提高,f-CaO质量分数降至1.64%,稳定性大大提高,符合建材化使用要求. 此外,进一步使用焦炭还原改性渣中的铁,轻松实现了渣铁分离,提高改性渣的易磨性.      

Recovering and recycling scrap from dumps containing steelmaking slags

The company Mittal Stil Temirtau has accumulated more than 13 million tons of steelmaking slag, and it annually adds another 600,000 tons of slag to this amount from ongoing production operations. Here, some of the iron from the production process is lost in the form of metallic iron and oxides. The total amount of iron lost is estimated to be 15%. Studies have established that discarded steelmaking slags contain up to 8% magnetic products. A slag-processing unit began operation at the dump in 2003 to recover scrap from the slag. The unit has a productivity of 120 tons of bank slag per hour and can process slag with an initial coarseness of up to 700 mm. Extracting iron-bearing products from steelmaking slags and returning them to the production cycle has reduced iron losses by 30% for the metallurgical conversion as a whole. __________ Translated from Metallurg, No. 1, pp. 80–81, January, 2006.     

钢铁渣的农业资源化利用

钢铁渣是钢铁冶金生产的主要固体废弃物,开发冶金炉渣的综合利用技术对于防止环境污染和促进冶金工业的长期可持续发展有十分重要的意义.钢铁渣的理化特性进行了简要的介绍,详细论述了其在农业生产上的资源化再利用技术以及施用钢铁渣肥料后的土壤环境效应.钢铁渣应用于农业生产可以使其含有的有益元素得到充分利用,不会对农产品及土壤环境造成危害,而且通过在钢铁渣中加入添加剂合成新型农业肥料可以有效地提高钢铁渣肥料的附加值,更好地满足农业生产的高产和优质的需求.     

A solid electrolyte oxygen sensor for steelmaking slags of the basic oxygen converter

Oxygen pressure in the slag phase is an important parameter in steelmaking processes. Consequently, an in situ solid electrolyte oxygen sensor for the steelmaking slags was developed in the present work. EMF measurements, optical examination, and EPMA analysis of cross sections of the electrolyte tubes used in laboratory experiments indicated that magnesia-stabilized zirconia was suitable for this purpose. The oxygen sensor was also tested on slags of a 100,000 kg LD converter at the end of the normal blowing operation. The stable oxygen pressure in the slag was successfully obtained by the simultaneous measurements of EMF and temperature. By using the oxygen sensor, a simple empirical relation was obtained between the oxygen pressure and ratio of ferric to the total iron ion content in the slag. Also, the oxygen pressure in the LD converter slag was found an order of magnitude higher than that in the metal at the end of the normal blowing operation.     

Processing of liquid steelmaking slags to obtain commercial products

The processing of liquid steelmaking slags to obtain a commercial product with specified properties and maximum iron extraction is considered. The performance of existing systems for liquid-phase reduction of the metal from slag and methods of liquid-slag processing is compared. Prototype equipment for slag processing is developed and tested at OAO OMK-Stal’ (Vyksa) on liquid electrofurnace slag and ladle (refining) slag.     

Smelting Oxidation Desulfurization of Copper Slags

 According to the mechanism of sulfur removal easily through oxidation, the process of smelting oxidation desulfurization of copper slags is studied, which supplies a new thinking for obtaining the molten iron of lower sulfur content by smelting reduction of copper slags. Special attention is given to the effects of the holding temperature, the holding time and CaF2, CaO addition amounts on the desulfurization rate of copper slags. The results indicate that the rate of copper slags smelting oxidation desulfurization depends on the matte mass transfer rate through the slag phase. After the oxidation treatment, sulfur of copper slags can be removed as SO2 efficiently. Amount of Ca2+ of copper slags affects the desulfurization rate greatly, and the slag desulfurization rate is reduced by adding a certain amount of CaF2 and CaO. Compared with CaF2, CaO is negative to slags sulfur removal with equal Ca2+ addition. Under the air flow of 0. 3 L/min, the sulfur content of copper slags can be reduced to 0. 00467% in the condition of the holding time of 3 min and the holding temperature of 1500 ℃. The sulfur content of molten iron is reduced to 0. 0008% in the smelting reduction of treated slags, and the problem of high sulfur content of molten iron obtained by smelting reduction with copper slag has been successively solved.     

Activity Calculation in Complex Metallurgical Molten Slag Systems Based on Regular Solution Model

 The activity of FetO is very important in ironmaking and steelmaking process. In order to predict the activity of FetO and optimize the operation conditions in ironmaking and steelmaking process, by application of regular solution model in molten slag systems, FeO-Fe2O3-SiO2 ternary system, FeO-Fe2O3-SiO2-CaO and FeO-Fe2O3-SiO2-NiO quaternary systems have been studied by the chemical equilibrium between H2/H2O gas mixture and liquid slag contained in solid iron. The values of interaction energy between cations concerning steelmaking slags have been determined by application of ferric-ferrous iron equilibrium and iron-ferric iron equilibrium. And then the activity of FetO can be calculated. The results show that the relative error is 39% in FeO-Fe2O3-SiO2 system and 18% in FeO-Fe2O3-SiO2-CaO system. The prediction of activities of FetO in the systems are in good agreement with the measurements and the regular solution model is valid for predicting the activity of FetO in complex molten slags systems. The activity of FetO in FeO-Fe2O3-NiO system have not been tested presently, and the calculated result can not be assessed.     

Manganese Distribution between FeO‐MnO‐SiO2–CaO–MgO‐Al2O3 Slags and Molten Iron

Pretreatment of high manganese hot metal is suggested to produce hot metal suitable for further processing to steel in conventional LD converter and rich manganese slags satisfy the requirements for the production of silicomanganese alloys. Manganese distribution between slag and iron represents the efficiency of manganese oxidation from hot metal. The present study has been done to investigate the effect of temperature, slag basicity and composition of oxidizer mixture on the distribution coefficient of manganese between slag and iron. Ferrous oxide activity was determined in molten synthetic slag mixtures of FeO‐MnO‐SiO₂–CaO–MgO‐Al₂O₃. The investigated slags had chemical compositions similar to either oxidizer mixture or slags expected to result from the treatment of high manganese hot metal. The technique used to measure the ferrous oxide activity in the investigated slag systems was the well established one of gas‐slag‐metal equilibration in which molten slags contained in armco iron crucibles are exposed to a flowing gas mixture with a known oxygen potential until equilibrium has been attained. After equilibration, the final chemical analysis of the slags gave compositions having a particular ferrous oxide activity corresponding to the oxygen potential of the gas mixture. The determined values of ferrous oxide activity were used to calculate the equilibrium distribution of manganese between slag and iron. Higher manganese distribution between slag and iron was found to be obtained by using oxidizer containing high active iron oxide under acidic slag and relatively low temperature of about 1350°C.     

Results demonstrating techniques for enhancing electrochemical reactions involving iron oxide in slags and C in liquid iron

Two techniques are described for the enhancement of the kinetics of reduction of iron oxide from slags by carbon in molten iron. Laboratory experiments have shown that the rate of iron oxide reduction by carbon-saturated iron can be increased by 5 to 10 times when the reaction is carried out under a reduced-pressure atmosphere. This effect is thought to be the result of the increased volumetric gas evolution through the slag layer and the associated increase in slag stirring. A model is presented, which relates the mass-transfer coefficient for ferrous ions in the slag to its stirring that is controlled by varying the ambient pressure. Additional laboratory experiments examined the electrochemical nature of iron oxide reduction from slag by carbon in liquid iron. Results indicate that the reduction of iron oxide from slag is increased in the presence of an applied electric field. The external circuit allows for the separation of the half-cell reactions associated with iron oxide reduction and decarburization and increases the reaction area available for the individual reactions. These results have significant implications for several important slag metal reactions, which occur during ironmaking and steelmaking operations.     

Metal losses during steelmaking in arc furnaces and methods for their decreasing

The structure of metal losses in steelmaking in ultrahigh-power arc steel-melting furnaces is estimated and refined using reported data and the results of our investigations. Methods for decreasing the iron losses in electric furnace steelmaking by performing organization and technological measures in arc-furnace plants and methods for utilizing the slags, dusts, and slimes of electric furnace steelmaking are considered. The pyrometallurgical utilization of the slags and dusts with the maximum iron recovery from them is shown to be promising.