Zinc leaching from electric arc furnace dust in alkaline medium

Physical and chemical properties of electric arc furnace （EAF） dust from Tianjin seamless Pipe Company were measured and analyzed. The zinc leaching tests in alkaline medium were carried out under variation of leaching agent concentration, leaching temperature, leaching cumulative time and solid-to-liquid ratio. The thermodynamics and kinetics of the zinc leaching process were also analyzed. The results show that the EAF dust contains 10% （mass fraction） zinc and the median particle size is 0.69 μm. The zinc recovery of 73.4% is obtained tinder the condition of 90 ℃, 6 mol/L NaOH, and 60 min leaching time. With the increase of concentration of NaOH and the cumulative time, zinc leaching will be significantly increased. The kinetics study demonstrates that the leaching reaction is chemically controlled and the reaction activation energy is 15.73 kJ/mol.

Heat Transfer Analysis for Industrial AC Electric Arc Furnace

The heat transfer analysis was performed for an AC electric arc furnace (EAF). Heat losses by conduction, convection and radiation from outer surface, roof, bottom and electrodes of EAF were determined in detail. Some suggestions about decreasing heat losses were presented.

Application of Extended Kalman Filter to the Modeling of Electric Arc Furnace for Power Quality Issues

Electric arc furnaces(EAFs)represent one of the most disturbing loads in the subtransmission or transmission electric power systems.Therefore,it is necessary to build a practical model to descript the behavior of EAF in the simulation of power system for power quality issues.This paper deals with the modeling of EAF based on the combination of extended Kalman filter to identify the parameter of arc current and the power balance equation to obtain the dynamic,multi-valued u-i characteristics of EAF load.The whole EAF systems are simulated by means of power system blockset in Matlab to validate the proposed EAF model.This model can also be used to assess the impact of the new plant or highly varying nonlinear loads that exhibit chaos in power systems.

Development and Application of Castables for Ladle Nozzle of Electric Arc Furnace

The castables for ladle nozzle were developed using brown corundum as the main raw material and the right amounts of complex additives . The influence of several additives on the properties such as strength and permanent linear change of the samples was studied . The results showed that applying complex additives improved the strength and the volume stability of the castables greatly. The campaign of the castables for ladle nozzle has increased from about 40 heats to 70 heats.

High Alumina Refractory Bricks for Electric Arc Furnace Roofs

This standard specifies the sort, technical requirement, test method, inspection rules, marking, packing, transportation, storage and quality certification of high alumina refractory bricks for electric arc furnace roofs.

Revamping design of an EAF automatic temperature measurement and sampling robot

The function,features,and architecture of a robot that performs automatic temperature measurement and sampling applied on a 150-t AC electric arc furnace(EAF)production line of Baosteel were presented,and the key points of design and revamping experience on the site layout,device protection,lance tool,probe container,measuring position control,and system safety were summarized.Furthermore,a valuable reference for the application of automatic temperature measuring and sampling robots in EAF steelmaking plants will be provided.

大容量直流电弧炉接入对电网谐波的影响分析

大容量直流电弧炉是高功率的非线性负荷,运行时会产生大量谐波,影响电网的电能质量。基于某钢铁集团130t直流电弧炉配电网架构及参数,建立了含治理装置的大容量直流电弧炉的动态仿真模型,分析了大容量直流电弧炉的谐波发射特性及其影响因素。通过现场实测和仿真结果,分析了大容量直流电弧炉接入电网后的谐波特性,验证了静止无功补偿器(SVC)的滤波效果,为直流电弧炉接入电网后的监督和治理提供了参考。

Flexible Power Supply System of AC Electric Arc Furnace

The AC electric arc furnace(EAF)is becoming a core apparatus of the modern steel industry.Nevertheless,it used to be a major threat of power quality in the traditional power supply system.In this paper,a flexible power supply system of the AC EAF is proposed,which is expected to completely alter its inherent cognition of impact load in the power grid.The basics of the power supply for EAF are first reviewed and the novel techniques to enhance the operation flexibility of EAF are introduced.The power circuit and the control structure are then presented,followed by the detailed strategies of various operations fully considering the features of EAF.A large disturbance stability criterion based on the mixed potential theory is also established for the practical application.Both electromagnetic transient simulations using PSCAD and benefit analyses verify the feasibility of the proposed system.

EAF steelmaking process with increasing hot metal charging ratio and improving slagging regime

A new electric arc furnace （EAF） steelmaking process with increasing hot metal charging ratio and improving slagging regime simultaneously was developed and applied in a 50 t electric arc furnace for more than a year at No. 1 Steelmaking Plant of Shanxi Taigang Stainless Corporation Limited. The essential fact of the new EAF steelmaking process was to charge hot metal in two portions or steps： firstly, 35wt%-40wt% hot metal was pretreated by blowing oxygen in a specially designed reactor for decar burization and improving hot metal temperature and melting premelted slag; secondly, 30wt% hot metal was charged into EAF with high basicity refining slags from ladle furnace （LF）-vacuum degassing furnace （VD） refining process. The results show that the hot metal charging ratio can reach to about 65wt%-70wt% for the new EAF steelrnaking process; meanwhile, the tap-to-tap time of a 50 t EAF can shorten by 5-10 min, the electricity consumption can decrease by 35-50 kW·h/t, the lime consumption can reduce by 10.5 kg/t of molten steel, and the content of harmful heavy metals in molten steel can be easily controlled to less than the upper limits of aimed steel specification or grade compared with the traditional EAF steelmaking process. In addition, the dephosphorization ability shows a slight strengthening, however, a small degree of lessening for desulphurization ability is observed for the new EAF steelmaking process, but the weakness of desulphurization ability cannot become an obstacle to its further application since a stronger desulphurization ability can be achieved during secondary refining of LF coupled with VD after EAF steelmaking process.

电炉铁水比对供氧量及其利用系数的影响研究

在高铁水比电炉生产过程中,铁水比是影响电炉供氧量及其利用系数的重要因素。本研究结合理论分析和现场数据分析,发现在终点碳含量在0.049%~0.1%,氧气消耗量及其利用系数与铁水比具有较好的线性关系,对高铁水比电炉冶炼制定供氧制度具有一定的借鉴意义。

直流电弧炉无功超短期滚动预测及控制

为提升直流电弧炉系统SVC装置动态补偿性能,提出了一种直流电弧炉无功超短期滚动预测及控制方法。首先,分析并揭示了直流电弧炉的控制原理及无功特性;其次,建立了直流电弧炉超短期无功滚动预测模型,基于AIC信息准则和历史冶炼数据实现了预测模型的定阶;然后,基于预测模型提出了直流电弧炉无功超短期滚动预测控制方法;最后,对预测及控制效果进行了仿真验证。与传统控制方法相比,采用预测控制算法后,瞬时闪变降低了31.16%。所提预测控制算法对直流电弧炉系统SVC装置的闪变抑制效果改善显著。

电弧炉采用直接还原铁炼钢工艺技术分析

分析了直接还原铁作为废钢替代品进行电弧炉炼钢的工艺技术特征,并阐明了影响冶炼电耗的主要因素。结果表明,熔池较大留钢量(≥40%)和诸如强化供氧、底吹和电磁搅拌的强化搅拌始终是促进熔化和缩短冶炼周期(可缩短8%~10%)的重要手段。直接还原铁比例超过30%宜采用连续加料,冶炼前期和中期加料速度一般等于熔化速度28~33 kg/min(供电功率1 MW),需匹配石灰和白云石以防渣线侵蚀,冶炼全程应喷碳使泡沫渣埋弧操作以保证供电效率。为降低冶炼电耗,应控制w[C]1%~4.5%、金属化率≥90%、w[SiO_(2)]≤6%、w[P]≤0.1%、w[S]≤0.04%,使用高C、高金属化率、低SiO_(2)、低P、低S和较高温度的热直接还原铁。采用直接还原铁竖炉和电弧炉相结合的紧凑短流程工艺是低碳节能和洁净化生产的重要方向。

Designing Evolutionary Wavelet Neural Network for Estimating Foaming Slag Quality in Electric Arc Furnace Using Power Quality Indices

In the present study,a novel approach based on an evolutionary wavelet neural network(EWNN)is proposed to estimate the slag quality in an electric arc furnace(EAF)employing power quality indices.In the EWNN,an evolutionary method is applied to train the parameters for a combination of neural networks and wavelets.I For this purpose,all of the electrical parameters for six melting processes are measured with a power quality analyzer,attached to the secondary component of an EAF transformer at a Saba steel complex,to estimate the foaming slag quality.Experimental results on various combinations of measured electrical parameters,applying the designed EWNN estimator,demonstrate that utilizing five leading indicators leads to the highest precision.The obtained 99%accuracy for estimating the foaming slag quality by EWNN compared to the other methods illustrates the proposed method's efficiency.

Technological innovations of electric arc furnace bottom-blowing in China

Nowadays, in China, the bottom-blowing technique plays an important role in accelerating the molten bath stirring and promoting the metallurgical reactions in electric arc furnace (EAF) steelmaking. The innovations of bottom-blowing technologies in EAF steelmaking were reviewed. The optimized bottom-blowing arrangement in EAF based on the furnace structure and the position of electrodes was introduced, and the fluid flow characteristics of EAF molten bath with bottomblowing were analyzed. Furthermore, bottom-blowing CO2 in EAF can facilitate the carbon-oxygen reaction reaching equilibrium and decrease the content of nitrogen in molten steel due to its special metallurgical properties. Pulsating bottom-blowing in EAF can effectively improve the molten bath stirring through the action of the unsteady bottom blowing gas streams, which could make the fluid flow field more disorderly than the steady bottom-blowing. And submerged O2 injection with CO2 in EAF can noticeably strengthen the EAF molten bath stirring, increase the production efficiency and improve the molten steel quality.

矿热炉用耐火材料及炉衬结构的研究进展

在全球“碳中和”背景下,为了达成铁合金行业节能、减排、环保的目标,矿热炉炉型正朝着越来越大型化的方向发展。炉衬的寿命决定了矿热炉的服役时间,而正确选择耐火材料、合理设计炉衬结构是矿热炉炉衬实现长寿命运转的重要保障。文章概述了矿热炉炉衬的毁损机理,探讨了不同铁合金冶炼时炉衬耐火材料的选择依据。重点阐述了炉衬结构的研究进展,对比分析了保温型炉衬和冷凝型炉衬的结构特点、工作原理、实际使用情况和经济性。最后从工业生产实际情况出发,在炉衬结构选择方面提出合理化建议。

电弧反应产生烟尘中余热利用之节能环保电弧炉的探讨

节能环保电弧炉中收尘孔与电极孔处飘出的余热烟尘气经过加料口各层螺旋翅片之间,在较大受热面积作用下,温度快速分散用于加热其上的混合颗粒料层,使混合颗粒料快速升温,可有效降低熔化能量。

以系统优化的观点看电弧炉炼钢技术的进步

以系统优化的观点对电弧炉炼钢技术的进步给予评述。指出钢铁生产过程是一类过程系统，并对过程系统工程和系统优化作了简要的说明。基于系统与环境构成更大系统的观点，对原料、能源、产品、成本和投资等外部因素对电弧炉炼钢的发展和制约作用作了讨论。在系统与子系统的层次上对电炉钢厂自身的特点、结构和典型流程予以说明，着重指出结构纵向化和生产规模化的趋向。对于电弧炉炼钢单元工序，以超高功率技术为主线点评了变压器功率级别的提高，高阻抗电弧炉、智能电弧炉的发展，直流电弧炉、竖炉一电弧炉、双壳电弧炉等炼钢技术的发展。

电弧炉兑铁水冶炼工艺的试验研究

在１８０ｋＶＡ实验型直流电弧炉上进行了兑入０～５０％铁水冶炼工艺的试验研究。结果表明，每加入１０％的铁水可使冶炼时间缩短约７％，电耗降低６％。吨钢氧气消耗量应随铁水比例的增加而增加，当铁水比例为３％时适宜值为２５ｍ３／ｔ。在高碳范围内熔池脱碳反应速度与供氧强度和氧气利用率成正比，而提高吹氧压力可以提高氧气利用率。在本试验条件下高碳范围内脱碳速度大于０．１％／ｍｉｎ，明显高于传统电炉。另外，兑铁水方法不同冶炼指标也有差异，根据厂家的实际情况合理选择兑铁水方法也十分重要。

含锌电炉粉尘配碳球团的冶金特性

以某钢铁公司含锌电炉粉尘为原料,配入适当的无烟煤制成含碳球团,焙烧球团通过还原煤保护冷却至室温后进行化学分析·研究了1150℃～1300℃的范围内,温度、时间和内配煤量对锌、铁的还原速率以及球团抗压强度的影响·研究结果表明:锌、铁的还原率均随焙烧温度、焙烧时间以及内配煤量的增加而提高;抗压强度随焙烧温度、焙烧时间的增加而增高,但随内配煤量的增加出现极值点·焙烧球团最佳的工艺参数:焙烧时间为15min,内配煤量为13 04%,焙烧温度为1250℃·此时锌的还原率为98 43%,金属化率为94 51%,抗压强度为800 6N/球·

基于能量平衡的电弧炉模型的仿真与参数辨识

为了研究电弧炉对电力系统的谐波影响,针对基于能量平衡关系的电弧炉(EAF)模型,利用粒子群算法(PSO)对仿真模型中的参数进行了辨识,得到的电压波形与实际波形吻合较好;在此基础上,在Matlab/Simulink中对该模型进行了仿真,将得到的仿真结果与实测谐波含量进行了对比,对比分析结果证明了该模型的合理性。研究结果表明,该建模方法能够较准确地反映电弧炉对电网的谐波影响,同时提出的参数辨识方法能够找到该模型参数合理的适应值,进而重现和预测电弧炉的负荷特性。