Microalloying and modification of steel with natural materials and industrial waste

The use of natural materials and industrial waste in the microalloying and modification of steel is studied. The metallurgical properties of a natural barium–strontium modifier are investigated, and its influence on the melting point of reducing slag is assessed. The results show that its industrial use is very promising. Terra software is used to assess the reduction of barium and strontium from their oxides by silicon and aluminum. The action of barium and strontium on the metal quality is analyzed. The potential of vanadium converter slag in microalloying steel with vanadium is established. The effectiveness of carbon from molten steel in the reduction of vanadium is assessed. Industrial tests are in good agreement with the theoretical findings. Recommendations are made for the optimization of microalloying and modification. The use of the materials here investigated improves the economics of steel production and considerably enhances the quality of the steel produced. The prospects for expanded of use of natural materials and industrial waste are discussed.     

Experimental study on slag splashing with modified vanadium slag

Slag splashing is the most effective technology to improve the furnace campaign of converter; however, due to the great difference of composition between the vanadium slag and the steel slag, the technology has not been applied in the vanadium extraction converter. To solve the serious problem of lining erosion in the vanadium extraction converter, in this paper, slag splashing with modified vanadium slag was studied. The results showed that the purpose of adjusting the state of vanadium slag can be achieved through the modification. The modified slag had good slag splashing performance. After slag splashing, the thickness of the furnace was increased by more than 10?mm. The content of CaO in the modified vanadium slag can be controlled less than 3%, and the quality of vanadium slag and semi-steel was not obviously affected. The metallic iron content in the slag was greatly reduced, which was beneficial to reduce the iron loss in the vanadium extraction process.     

提钒转炉溅渣护炉试验研究

溅渣是提高转炉炉龄最有效的技术,但由于钒渣与钢渣成分差异较大,溅渣护炉技术尚未在提钒转炉上得到应用.为解决提钒转炉炉衬侵蚀严重的问题,对改性钒渣溅渣进行了研究.结果表明,通过改性可以达到调整钒渣状态的目的.改性后的钒渣具有良好的溅渣性能,溅渣后炉厚增加10 mm以上.改性钒渣中w(CaO)可控制在3％ 以下,对钒渣和半...     

含V2O5、TiO2钢渣熔化性质的研究

研究了主要组元对含V2O5、TiO2钢渣熔化性温度及熔化区间的影响,提出了含V2O5、TiO2钢渣进行溅渣护炉的控制方向.通过电子显微镜分析V、Ti元素在钢渣矿相中的含量,找出了含V2O5、TiO2钢渣与普通钢渣熔化规律差异的原因.     

减少转炉提钒过程碳烧损

摘要：为了有效减少了转炉提钒过程的碳烧损量,在硅钼炉内进行氧化性炉渣与铁水在不同温度下的渣金反应实验,发现炉渣与铁水的反应速率随温度的升高而加快;温度越高铁红(Fe2O3)将钒氧化到极值的速度越快,但达到极值后钒会被还原回铁水中,且还原速度也随温度的升高而提高;温度越高钒渣中的钒被铁水中碳还原的量越大。根据实验结果对转炉提钒工艺进行了优化,吹炼温度为1340～1350℃时加入冷却剂,控制较低的终点温度,在钒氧化率不降低的情况下,碳烧损率从19.39%降到17.91%、碳烧损量从0.82%减少到0.76%,有效减少了转炉提钒过程的碳烧损。     

钒钛钢渣配制AC-13型沥青混合料的研究

钒钛钢渣具有较好的力学和表面特性,研究了其作为AC-13型沥青混合料集料的可行性。结果认为,钒钛钢渣可以作为AC-13型沥青混合料的集料,该沥青混合料的配合比设计为:钒钛钢渣(4.75~13.2 mm)、钒钛钢渣粉(0.075~4.75 mm)、矿粉三者之比为58∶40∶2,外配油石比最佳比例为4.9%。     

钒钛转炉钢渣熔化特性的研究

测定了钒钛钢渣在不同组元含量条件下的熔化性温度及熔化区间。通过电子显微镜分析V、Ti在岩相中的含量,找出了钒钛钢渣与普通钢渣熔化规律差别的原因。提出了钒钛钢渣进行溅渣护炉的控制方向。     

以转底炉技术利用钛资源的基础研究

提出了一种以转底炉煤基直接还原技术利用钛资源的新工艺及两个不同的方案。该工艺以攀枝花钒钛磁铁精矿或钛精矿粉、煤粉和少量添加剂组成的复合球团为原料,在高温加热条件下将含钛矿中的氧化铁还原为铁,经渣铁分离后获得生铁和富集了的钛渣。第一方案以钒钛磁铁精矿配20%钛精矿为原料,还原后渣铁自然分离,得到块铁和品位为50%左右的钛渣;第二方案以钛精矿为原料,还原后经破碎磁选分离得到粒铁和TiO2富集率为～75%的钛渣。对这两种方案均进行了初步试验,确定了合理的工艺条件。     

Noninertial control of the blast furnace and the carburization of iron

Essentially, the reduction of iron in the blast furnace and the oxidative smelting of steel in the oxygen converter are opposing processes. In addressing the carburization of iron in the blast furnace and its decarburization in the converter, we consider noninertial control of the zonal blast-furnace processes. A functional relation is established between the parameters of the zonal processes and the parameters of the hot blast, the reducing gas, and the blast-furnace gas. On that basis, the batch and coke consumption and the yield of metal, slag, and gas in unit time may be strictly and continuously regulated. That, in turn, permits monitoring of the ore load on the coke. Noninertial control of the zonal blast-furnace processes by this means permits regulation of the slag’s oxidative potential, the ore load, and the consumption of injected dusty iron oxides and hence reduction of the carbon content in the hot metal to 2.0–2.5% or less. This approach leads ultimately to the creation of a single-stage process from ore to steel.     

Mechanism and Kinetics of Optimized Slag Formation in an Oxygen Converter

One of the most important technical requirements in modern high-speed converter steelmaking is early formation of the furnace slag. Early slag formation helps optimize conditions for the oxygen blow and facilitates thorough refining of the steel in the converter. The main factors that determine the rate of slag formation are the contents of oxides of iron and manganese in the slag, the temperature of the steel, and the conditions under which the lime is added. When converter steelmaking is done on low-silicon, low-manganese pig iron with use of a portion of the slag from the previous heat, the slag tends to form earlier and intensive decarbonization takes place as the blow proceeds in the dynamic regime. Such steelmaking is also more efficient as a whole, since it reduces the amount of silicon and manganese in the pig and shortens the heat. __________ Translated from Metallurg, No. 8, pp. 42–43, August 2005.     

Resource-saving direct alloying of steel

The development of the alloying and modification of steel by oxides, including natural materials, is very promising. Potential materials include barium–strontium carbonate ores, nickel concentrates, and vanadium converter slag, which may be used to produce steel with improved properties, without the expensive process of producing ferroalloys and intermediate alloys. Considerable research is required to improve steel-making processes. Thermodynamic modeling may be used for that purpose. In the present work, thermodynamic modeling is used for elementary systems involved in the extraction of barium, strontium, vanadium, and nickel from their oxides by means of different reducing agents. The results indicate that microalloying and modification of steel by inexpensive materials is possible; and permit the determination of the type of reducing agent and the optimal quantities employed. The Terra software used in thermodynamic modeling permits the determination of the equilibrium composition of the multicomponent heterogeneous system for high-temperature conditions, on the basis of the maximum-entropy principle. The reducing agents considered are carbon, silicon, and aluminum. The influence of the temperature and reducing-agent consumption on the reduction processes is investigated. The results regarding the reduction of barium and strontium show that silicon or aluminum is the best reducing agent when barium-bearing oxide materials are employed. The optimal reducing-agent consumption corresponding to maximum reduction of the barium and strontium is determined. The possibility of reducing nickel by carbon is confirmed. It is found that vanadium may be reduced by silicon or carbon or a complex process in which carbon is the predominant reducing agent. The results permit the development of a resource-saving technology based on oxides for the alloying, microalloying, and modification of Fe–C systems.     

降低提钒脱硫炼钢钢铁料消耗工艺优化

为了降低炼钢全流程钢铁料消耗,结合西昌钢钒炼钢厂装备及工艺条件,在提钒工序提出低硅质量分数铁水采用石英砂调渣、优化供氧制度等工艺改进措施以降低钒渣TFe的质量分数;在脱硫工序提出优化脱硫剂w(CaO)/w(Mg)质量分数比以减少脱硫渣量及喷溅;在转炉炼钢工序提出优化转炉终点温度和终点碳质量分数以降低转炉渣TFe质量分数。通过工艺改进措施的实施,钒渣TFe质量分数由28.59%下降到26.72%,脱硫铁损的质量分数由2.94%下降到2.63%,转炉渣TFe的质量分数由20.09%下降到19.00%。炼钢全流程钢铁料消耗由2015年12月的1 112.73降低到2016年4月的1 107.55kg/t,达到国内同类型企业中的先进水平,取得了巨大的经济效益。     

高炉炉缸区钒氧化物的还原试验

炉缸区钒氧化物的还原对钒的收得率具有重要影响。通过研究炉渣成分和温度对钒氧化物还原的影响,结果表明:二元碱度对钒氧化物还原影响显著,钒氧化物的还原率随着二元碱度的增加而增加;MgO、Al_2O_3含量增加,钒氧化物的还原率先升高后降低;TiO_2含量增加,钒氧化物的还原率降低,且TiO_2含量超过11%时钒氧化物的还原率大幅降低;钒氧化物的还原率随着温度的增加而升高。当承钢高炉渣的二元碱度1.2、Al_2O_3含量14%、MgO含量10%、TiO_2含量9%、炉渣温度控制1 500℃时,钒氧化物的还原达到最佳,还原率达到90%左右。     

Process of Re-Resourcing of Converter Slag

 The process of “re-resourcing of converter slag” was put forward based on the analysis of the existing steel slag treatment process. The converter slag obtained from Jinan steel plant was studied. After grinding, the slag contained 33% of iron particles, 5484% of magnetic part (wTFe=20%), and 4184% of non-magnetic part, which could be used for making cement directly. At a temperature below 1000 ℃, the non-magnetic Fe2O3 in the slag could be efficiently reduced to magnetic iron by pure H2 and CO. The slag after precise reduction had high degree of dispersion and did not get sintered, which provided an optimum condition for the separation of iron and impurities. To separate the slag and enrich the iron after reduction, the laboratory-scale device of magnetic separation was designed and made. The process of slag re-resourcing, which included magnetic sorting, precise reduction, magnetic separation, and removal of free calcium oxide (f-CaO), was proposed to obtain iron-rich magnetic materials and cement adulterant materials. Through this process, 33 kg iron particles, 150 kg iron-rich material and 700 kg cement could be obtained in each ton slag. Besides, this process to recycle converter slag had a lower energy and material consumption and no pollutant emission.     

转炉渣热闷法直接上线工艺处理概况及应用

转炉渣含丰富的金属氧化物、微量元素及矿物,具有很高的回收利用价值。钢渣热闷法以其环保低耗、回收率高的特点被逐渐应用于钢渣的预处理工艺。简要介绍转炉渣的组成和性能及质量影响因素、焖渣工艺的原理及方法和现状,重点分析研究了某公司突破性地实现了转炉渣焖渣坑直接上线深度处理工艺。该工艺通过分坑倒入转炉渣、多次分段打水、颚破初破和棒磨机细磨后磁选等工艺、设备的优化,解决了当前焖渣工艺存在的焖坑内板结、焖后红块的问题,提高了钢渣质量性能,达到尾渣粒度最小化和金属铁回收量最大化,使其具备直接上线的能力,同时减少了扬尘污染与外排水资源浪费。该工艺实现了:焖渣坑直接上线比例达43%以上,脱碳线上线率达76.3%以上,尾渣破碎后粒度小于10 mm,且处理后尾渣含铁量小于1.06%,金属回收率得到大幅提升,对钢渣的回收利用具有指导意义。      

碱度对转炉钢渣熔融还原提铁的影响

为了使熔融钢渣的"渣"和"热"得到双利用,采用熔融还原法进行了钢渣提铁实验,探讨了二元碱度对还原提铁的影响.结果显示随着碱度的增大铁的回收率及金属化率呈先升后降的趋势,在碱度1.1时铁的回收率和金属化率达到最大,分别为95.8%和99.2%.与炼钢用生铁国标相比,回收的铁块中C、Si、Mn的含量较低,而S、P含量远远高于炼钢用生铁.     

Metallurgical value of converter slag

The characteristics of OAO ZSMK converter slag are investigated, including a series of experimental melts in a laboratory arc furnace. The losses of iron with converter tailings slag at OAO ZSMK after primary magnetic separation in the slag fields amount to 22.7%, on average (9.0% metallic iron + 13.7% iron oxides). In sorting the slag, the large fractions are enriched with iron oxides—primarily FeO and Fe₃O₄; Fe₂O₃ passes to the small fractions. In melting converter slag, some of the iron is recovered, with increase in the content of metallic iron to 11.7%, on average. Most of the metallic iron is concentrated in the large fractions (more than 40 mm), where its content is 18%, on average, as against 5–6% in the smaller fractions.     

脱磷炉利用脱碳炉返回渣的试验

为了达到节能降耗的目的,脱磷炉采用回吃脱碳炉返回渣的工艺。主要研究了脱碳炉渣的熔化特性以及作为炉料在脱磷炉中的应用效果。结果表明,通过每炉次加入约3.5t的脱碳炉渣,可平均节约1.01t石灰,4.71kg/t钢铁料消耗,脱磷炉终点炉渣的岩相组成主要由硅酸二钙、RO相、玻璃相和少量的金属铁粒组成。加入返回渣后脱磷炉终点炉渣中硅酸二钙和铁酸二钙含量有所增加,玻璃相含量降低,炉渣碱度有所升高,脱磷炉终点钢水成分控制水平有所提高。由此表明,采用脱碳炉渣返回脱磷炉循环利用减少了石灰等原辅料和钢铁料消耗,同时达到了预期的脱磷效果。     

Simulation and Application of Swirl‐Type Oxygen Lance in Vanadium Extraction Converter

Stirring effects and impacting characteristics of conventional and various swirl‐type oxygen lances (Swirl angles are 5°, 10°, and 13°, respectively) on the molten pool were studied. The mixing time, impacting depth and impacting diameter were measured by water model experiment. The flow field characteristics of gas–liquid two phase flow were simulated using Fluent software. It is found that 10° swirl‐type oxygen lance injection can get the shortest mixing time which is only 47.6 s. The area surrounded by isovelocity is larger in molten pool when injecting by the swirl‐type oxygen lance. When injecting by the 10° swirl‐type oxygen lance, the area is the largest and the flow velocity of liquid steel is the highest. On this basis, the 10° swirl‐type oxygen lance was experimented in 150 t vanadium extraction converter. The experiment shows that the swirl‐type oxygen lance can guarantee the normal smelting process. Compared with the conventional oxygen lance, the reduction ratio of vanadium content in semi‐steel is 17.8%, vanadium extraction rate is increased by 5.1%, V₂O₅ grade of vanadium slag is increased by 0.93% and iron loss is reduced. It provides a new technology to improve the recovery of vanadium resources in converter.     

包钢炼钢厂转炉工艺优化

炼钢和连铸生产过程中产生了大量的含铁尘泥、连铸切割渣、渣钢等含铁物质,为了减少这些含铁物质的外排和污染,在转炉中加入这些含铁物质,但是转炉工艺操作出现了波动,部分炉次钢铁料消耗较高。通过采用"留渣+双渣"工艺,在留渣的基础上将转炉吹炼分为两个阶段;同时在吹炼过程中对底吹进行控制,显著地降低喷溅发生。现有操作工艺进行优化后,钢铁料、渣料消耗大幅减少,显著地降低了转炉炼钢的生产成本。