Study of a blast-furnace smelting technology which involves the injection of pulverized-coal fuel, natural gas, and an oxygen-enriched blast into the hearth

Studies were made of features of a blast-furnace smelting technology that involves the injection of natural gas (NG), oxygen (O₂) and pulverized-coal fuel (PCF) into the hearth. The technology has been implemented in the compensation and overcompensation regimes, which has made it possible to maintain or improve the gasdynamics of the furnace, the conditions for the reduction of iron oxides, the heating of the charge, and PCF combustion in the tuyere zone as PCF consumption is increased and coke use is decreased. Under the given conditions, with the blast having an oxygen content of 25.64–25.7%, the hearth injection of 131–138 kg PCF and 65–69 m³ NG for each ton of pig iron has made it possible to reduce coke consumption by 171–185 kg/ton pig (30.2–32.7%), reduce the consumption of comparison fuel by 36–37 kg/ton (5.2–5.3%), and lower the production cost of the pig iron by 43–49 hryvnas/ton (3.7–6.4%). Here, furnace productivity has increased 3.8–6.5%, while the quality of the conversion pig iron remains the same as before. Measures are being implemented to further increase the level and efficiency of PCF use. __________ Translated from Metallurg, No. 5, pp. 41–44, May, 2006.     

Effectiveness of using oxygen-gas burners in modern arc steelmaking furnaces

Oxygen-gas burners have become a standard component of modern electric-arc steelmaking furnaces worldwide as a means of increasing productivity and reducing electric power consumption. The use of such burners in these furnaces is expedient from both an economic and an energy standpoint. On the average, the use of 1 m³ of natural gas to heat the scrap in the furnace charge saves 0.6–0.8 m³ of natural gas for the refining operation. The amount of heat obtained from the combustion of natural gas can be increased significantly by equipping arc steelmaking furnaces with high-capacity rotary oxygen-gas burners that allow changes to be made to the direction of the flame.     

Introduction of a System for Intensifying Steelmaking in a DSP 100 Arc Furnace at Ural Steel

Ural Steel has rebuilt its arc steelmaking furnace No. 1, equipping it with wall and door multi-lances that are moved into position by hydraulic manipulators. The changes have allowed the company to introduce a system that speeds up the steelmaking operation. Use of the system has shortened the average heat to 89 min. Unit electric-power consumption was previously 406 kWh/ton liquid steel and electrode consumption averaged 4.2 kg/ton. The replacement of 25 tons of solid pig iron by the same amount of liquid pig in each heat has made it possible to lower the average unit consumption of electric power to 382 kWh/ton and shortened the time of operation of the furnace under current to 50 min. The coefficient characterizing the use of oxygen in the blow is now within the range 0.86–0.92%.     

Russian electrometallurgy: Achievements,problems, prospects

The changes in the Russian metallurgy, in particular, electric furnace steelmaking, having occurred in the recent years are analyzed. The main increase in the steelmaking output is due to putting into operation of new electric furnaces in new miniworks and enterprises equipped earlier with open-hearth furnaces. Reaching the rated capacity of a furnace in Russia substantially lags behind foreign enterprises. Only 30–35% of the Russian market of corrosion-resistant steel are provided by Russian metal.     

Use of liquid pig iron in electric-arc furnaces

Conclusions A technology for adding liquid pig iron to a DSP-10017 furnace has been developed, tested, and introduced commercially. The technology reduces the consumption of electric power by 44–55 kW·h/ton steel (to 406.3 kW·h/ton) and shortens the heat by an average of 10 min. The duration of the trial heats was 1 h, 51 min. Certain technological parameters of the steelmaking operation were determined. For example, it was established that the molten pig iron should be added only after complete melting of the scrap metal and that unit electric-power consumption during the addition should be within the range 230–320 kW·h/ton scrap. A total of 4–5 tons of iron ore (sinter) and 4–6 tons of lime should be added to the cold charge and the secondary scrap charge. The high SiO₂ content of the slag makes it necessary to carefully discharge the slag over the sill of the working door after the liquid pig iron has been added. Kuznetsk Metallurgical Combine. Translated from Metallurg, No. 6, p. 32, June, 2000.     

电弧炉高效多位SGOB用氧技术改造

介绍了石钢电弧炉高效多位SGOB用氧技术改造,利用炉壁氧枪实现二次燃烧,极大地提高了二次燃烧率,吨钢电耗降低50kW·h,生产效率提高约15％。     

Possibilities for intensifying blast-furnace smelting

An article published earlier by I. E. Sperkach and I. F. Kurunov [Metallurg, No. 2 (2005)] presented additional information in support of the author’s proposal that blast-furnace smelting practice be changed over to the use of 600 kPa top-gas pressure and a high-parameter combination blast (oxygen content up to 42%, natural-gas consumption up to 250 m³/ton pig). A blast-furnace complex which operates at high pressures with such a blast and which includes equipment to compress and heat the blast, a compact blast furnace, a gas-cleaning system, and a waste-gas turbine holds promise as a new generation of engineering system that would significantly enhance the competitiveness of blast-furnace smelting. This is a continued examination of the problem discussed by I. E. Sperkach and I. F. Kurunov in [1]. __________ Translated from Metallurg, No. 6, pp. 42–45, June, 2006.     

The use of siderites in blast furnaces operated on unfluxed pellets

Bakal siderites represent an important source of iron ore that can be used in the production of high-quality pig iron and steel. Their value in this regard stems from the stability of their chemical composition, low content of harmful impurities (sulfur, phosphorus), good reducibility, and good strength in the roasted state. These advantages, combined with the favorable composition of the country rock-which has a basicity (based on CaO + MgO/SiO₂) of up to 2.6-makes it possible to classify these siderites as iron-fluxes that can be used effectively in a blast furnace. Roasted siderite concentrate (RSC) can be used efficiently in the blast-furnace charge to make different grades of manganese-bearing foundry iron as long as unfluxed pellets are also employed. On the average, the addition of 10 kg of RSC to the charge per ton of pig iron reduces the consumption of dry skip coke by 0.6–1.5 kg/ton pig and increases furnace productivity by 0.9–2.0 tons/day by decreasing the amount of raw flux needed and increasing the iron content of the fluxed part of the charge. __________ Translated from Metallurg, No. 8, pp. 51–55, August, 2006.     

淘汰平炉 发展全连铸 优化炼钢生产结构

重钢在全国率行淘汰了平炉炼钢，发展转炉炼钢和全连铸生产工艺，文中根据重钢生产实践，从连铸技术发展，平炉和转炉炼钢成本比较，转炉炼钢厂连铸坯品种开发，和安置平炉厂下岗人员四个方面，论述淘汰平炉，优化炼钢生产结构问题，提出应创造条件，尽早淘汰平炉，发展全连铸的观点。     

Supplying steel scrap for electric steelmaking in Russia

This article reports on the steel-scrap balance in Russia and analyzes the demand for this resource from the steelmaking industry, as well as the potential sources of steel scrap. It is shown that the continuing growth of electric steelmaking in Russia will soon be challenged by shortages of steel scrap in the market and the need to more thoroughly process the scrap that will be available. Calculations show that when it is necessary to charge additional steel scrap into an arc furnace twice after the cold charge, the unit consumption of electric power is increased by 8.7 kWh/ton cast semifinished product and the heat is lengthened by 3 min. __________ Translated from Metallurg, No. 6, pp. 46–50, June, 2006.     

Oxygen converter steelmaking at the MMK

Information is presented on the invention, ensuing growth, and future prospects of oxygen-converter steelmaking at the MMK. __________ Translated from Metallurg, No. 1, pp. 43–44, January, 2007.     

Scrap melting in continuous process rotary melting furnace Part 1 – Bench scale furnace trials

Abstract

A heat transfer model was developed for scrap melting in an oxyfuel fired continuous process rotary melting furnace (CPRMF), which was envisioned as a replacement for the electric arc furnace in minimill steelmaking. The results are presented in a two part series. This first paper describes the bench scale CPRMF, the experimental procedure, and the operational results which will be used to validate the model. Two groups of copper melting trials were performed to explore aspects of furnace operation such as oxygen enrichment and slag thickness. The experimental results indicated that furnace thermal efficiency was significantly improved by moving from 37 to 80% oxygen in the combustion air and, extrapolating the results, would be ～30% for oxy fuel firing. With the constant oxygen level of 53%, the introduction of a slag layer significantly lowered the efficiency from 22 to 18% for 1·3 cm slag and 12% for 2·5 cm slag.     

Study of ways of reducing coke use at non-integrated metallurgical plants

To reduce the costs of blast-furnace smelting, the Svobodnyi Sokol plant has devised a comprehensive program of organizational-technical measures that include study of ways of reducing coke consumption. To do this, the plant began operating its blast furnaces with schungite when making foundry and conversion pig irons. Using schungite in the charge employed to make foundry iron makes it possible to save a significant (10–15%) amount of coke. The value of the coefficient that characterizes the replacement of coke by schungite varies broadly and can reach 1.0 or more, depending on the grade of iron being made and the furnace operating regime. The same coefficient has a value of 0.57 kg coke/kg schungite when 12–15 kg schungite/ton pig is used to make conversion pig iron. __________ Translated from Metallurg, No. 3, pp. 38–42, March, 2006.     

应用COMI炼钢工艺进行转炉全铁水冶炼基础研究

基于二氧化碳与氧气混合喷吹(简称COMI)炼钢工艺热力学理论计算及实验研究,建立了转炉全铁水COMI炼钢工艺物料与能量模型.研究发现:应用COMI炼钢工艺进行转炉全铁水冶炼工艺研究不仅能解决转炉全铁水常规冶炼过程中存在的大渣量及大喷溅问题,而且在提高转炉煤气热值,降低转炉吨钢氧耗及石灰消耗、调节矿石加入量方面有显著效果.     

What direction-steel?

Resource planning for the steel industry is the subject of this 50th Howe Lecture. After first proving that there will be a good market for steel products in the future, particularly in the auto industry as quality requirements are upgraded, the paper describes what iron- and steelmaking technologies may be expected to satisfy these demands. Iron ore supply will not be a problem in the foreseeable future and so most of the research work will be directed at reducing transportation costs and upgrading the raw material. Recent projected blast furnace technological advances are discussed with the emphasis on coke replacement schemes that will help to achieve coke rates of 600 lbs. or less per ton of hot metal. The direct reduction scene is reviewed with special application to reducing electric furnace steelmaking costs. Assessment of steelmaking techniques, both new and old, indicates that the basic oxygen process, whether it be top-, side-or bottom-blown, or even continuous, will dominate the steelmaking scene until the end of this century. In particular, a discussion of the IRSID process of continuous steelmaking is highlighted as the most promising of these schemes. A final look at steelmaking concludes that the electric process will, by 1995, match B.O.F. tonnage, especially with the increasing demand for specialty steels and as the open hearth is phased out. Summarizing the resource planning picture is a section on the most important raw material—energy. The paper points out that even though total energy consumption by the steel industry is continually increasing, steelmakers have done well in improving their efficiency of energy use by continuously decreasing the energy used per product ton. Nevertheless, shortages of energy raw materials are in sight, with the exception of uranium. The only long term hope is in the development of the breeder type nuclear reactor and this must be done before the end of this century.     

副枪技术在莱钢120 t转炉上的应用

介绍了莱钢120 t转炉副枪的应用情况,莱钢炼钢厂通过不断优化数学模型和完善修改各项规程制度使副枪运行得到了稳定,基本上取消了转炉倒炉作业,并对转炉炼钢工艺操作进行了优化。转炉各项指标得到了一定的提高,碳温双命中率达到了90%以上,冶炼周期平均缩短了4 min,转炉生产能力提高了10%,钢铁料消耗降低11 kg/t(钢)。同时降低了耐材消耗,提高了钢水质量、稳定了钢水成分,为开发优质品种钢创造了有利条件,实现了从经验炼钢到智能炼钢的转变。     

Material Metabolism and Environmental Emissions of BF-BOF and EAF Steel Production Routes

As an energy-intensive industry, iron and steel production are suffering from the resource and environmental issues. Blast furnace—basic oxygen furnace (BF-BOF) process and electric arc furnace (EAF) process are the two most common routes of steel production. Therefore, it is very important to quantify the industrial metabolism for the two routes. In this work, material flow analysis is used to comparatively investigate the energy efficiency, material efficiency, and emissions intensity at the enterprise level. The results show that the total energy consumption and material consumption per ton of steel of the BF-BOF route are 2.8 and 11 times larger than those of the EAF route, respectively. In addition, the emission intensities of dust, CO₂, SO₂, NO₂ and CO of the BF-BOF route are 7.7, 2.6, 92.6, 33.5, and 12.0 times greater than those of the EAF route, respectively. To achieve a more sustainable steel industry, some policy recommendations are put forward finally.     

铁钢比变化对吨钢综合能耗影响分析方法

 在碳达峰、碳中和背景下,增加废钢消耗比例、降低铁钢比可直接影响钢铁企业吨钢综合能耗下降,是中国长流程钢铁企业能效提升、节能降碳的有效路径,已成为钢铁行业研究热点。首先结合长流程钢铁生产实际从热量平衡角度简要分析了降低铁水热量损失、提高废钢入炉温度、降低转炉出钢温度等降低铁钢比的主要途径和相应技术措施。为了完整量化分析铁钢比变化对钢铁企业吨钢综合能耗的影响,以钢铁企业系统节能原理为基础,在传统的铁前工序钢比系数、转炉炼钢工序能耗变化影响分析的基础上,增加了由于铁钢比变化导致吨钢余能回收对吨钢综合能耗的影响,并提出了铁钢比变化对长流程钢铁企业能耗影响定量分析方法。最后以若干钢铁企业实际数据为例进行了定量分析,在该案例条件下,铁钢比从基准期0.950降低至统计期0.790,铁前工序钢比系数、转炉炼钢工序能耗、吨钢余能回收三者变化分别影响吨钢综合能耗下降71.282 kgce/t、下降1.000 kgce/t、增加9.687 kgce/t,合计影响吨钢综合能耗下降62.595 kgce/t。该案例定量分析显示铁钢比平均每降低0.01,吨钢综合能耗下降3.912 kgce/t,铁钢比下降能够有效提升长流程钢铁企业吨钢综合能耗水平。     

Effect of fluorspar and other fluxes on slag-metal equilibria involving phosphorus and sulfur

The effect of additions of fluorspar-and potential substitutes such as borate, manganese ore, and ilmenite—to basic steelmaking slags on the equilibrium phosphorus and sulfur distribution ratio has been studied at 1550δC. From laboratory slag-metal equilibrium studies it was found that the presence of CaF2 in concentrations between 1.5 and 5 wt pct in the slag (equivalent to 2 and 6 kg of fluorspar per ton of steel) lowered the equilibrium phosphorus content in the metal by about a factor of three. The use of B₂O₃, manganese ore, or ilmenite (the active ingredient in Sorel flux) did not affect the equilibrium phosphorus content of the metal. The effect of CaF₂ is ascribed to a lowering of the activity of P₂O₅ in the slag. Good agreement was found between the metal phosphorus content obtained from open-hearth plant data (no fluorspar added) and the present laboratory data for slags not containing CaF₂. None of the fluxes studied in this work, including CaF₂, improved the equilibrium sulfur distribution between metal and slag. The present results indicate that the choice of a substitute for fluorspar in an actual steelmaking operation, except when phosphorus presents a problem, should be based primarily on the cost of using the fluorspar substitute, including any change in refractory costs resulting from using the substitute.