不锈钢冶炼渣铁浴熔融还原动力学实验研究

通过10 kg级小型不锈钢冶炼渣熔融还原试验,研究了不锈钢废渣在1 500～1 650℃温度范围内的熔融还原动力学行为,认为还原反应体现在两个阶段:反应初期不锈钢废渣熔解为反应的控速环节;而反应后期界面处的化学反应演变为反应的控速环节.从整体熔融还原试验上看,不同阶段对炉渣组成有着不同的要求:反应初期需要降低熔渣熔点,能有效促进形成液态渣,以提高不锈钢渣的熔解速度;反应后期需合理调节炉渣流动性以加速熔融还原反应.故可以通过炉渣参数优化以求在保证终渣的残铬达到较高回收的前提下尽可能提高熔融还原的速率.     

Kinetics of isothermal reduction of stainless steelmaking dust pellets

The stainless steelmaking dust pellets were reduced in isothermal temperature condition simulating the direct recycling practice in the stainless steel production and the kinetics of the reduction process was investigated.The pellets were formed after mixing the dust with carbon as the reducing agent and dolomite as the binder and smelting flux. An electric furnace was used to heat the pellets and an electrical microbalance was used to check the mass of the pellets in the reduction process. The reduction rate was calculated according to the data of pellet mass change in consideration of the evaporation of moisture, zinc and lead at high temperature. The results of the experi-ments show that the reduction process is in two consecutive stages. The reduction kinetic models were set up for each stage and the kinetic parameters such as activation energy and frequency factor were determined. The apparent activation energy of the first stage is 21.69 kJ/mol, and this stage is controlled by chemical reaction. The apparentactivation energy of the second stage is 17.35 kJ/mol, and this stage is controlled by the diffusion of carbon monox-ide through the resultants of reaction.     

图像处理技术的钢水熔炼终点识别及控制

结合企业实际生产条件，对用中频熔炼炉熔炼过程中测温和扒渣方法进行了改进。用数字图像处理技术对熔炼过程中钢水液面的图像进行分析处理，来检测钢水的温度以及表面是否存在钢渣，自动控制机械手扒渣以及自动控制中频炉的输入功率来达到钢水的升温和保温，最终判断熔炼过程的终点。该系统的应用使得熔炼过程的自动化程度大大提高。     

新一代洁净钢生产流程的理论解析

通过对新一代洁净钢生产流程中主要元素选择性氧化还原的热力学分析,并结合首钢京唐公司铁水"全三脱"生产洁净钢的技术实践,研究了新一代洁净钢生产流程中S,P,C等主要元素的控制规律,并对新一代洁净钢生产流程进行了理论解析,提出了需要进一步解决的若干工艺问题.研究表明:采用CaO/CaF2脱硫剂的KR法脱硫,可使铁水中S含量稳定地降到0.0020%以下,终点硫的控制主要取决于脱磷转炉中的回硫量,减少废钢和渣料等辅助材料带入的S以及适当提高脱磷炉渣碱度是减少半钢回硫量的关键;在较低温度(1300 1350℃)和较高氧位条件下造碱度合适的渣,是脱磷转炉实现脱磷保碳的关键,对于冶炼普通低磷钢,将脱磷炉半钢P控制在0.03%以下,则可将脱碳转炉终点磷控制在0.006%以下,而对于冶炼超低磷钢,则需将半钢P含量控制在0.008%以下,转炉终点磷可以降低至0.0020%以下;脱碳转炉少渣冶炼、降低铁耗以及高碳出钢是新流程降低洁净钢生产成本和提高钢液洁净度的重要技术特征.     

方圆坯连铸机引锭杆下滑现象的研究与改进

结合华中某特钢方圆坯连铸机在开浇至脱引锭阶段出现引锭杆突然下滑导致结晶器液面波动的现象，综合分析引锭杆下滑的各种影响因素，强化操作规范、加强设备点检等人为因素和针对设备自身存在的客观问题进行改造，有效地降低引锭杆下滑的概率，保证生产工艺参数的稳定。     

浅谈如何减少生产低碳低硅铝镇静钢时结晶器卷渣

通过对低碳低硅铝镇静钢生产过程中结晶器卷渣机理进行分析，提出了稳定结晶器液位、防止水口堵塞、提高保护渣的熔速、黏度以及表面张力、保证合适的浇注温度和拉速、合理的耐材烘烤制度、选用合适的振幅和频率以及采用正确的加渣捞渣操作等技术措施，取得了控制夹渣的良好效果，使铸坯夹渣率从24.16％降低到2.62%，解决了结晶器卷渣问题。     

A New Pyrometallurgical Process for Producing Antimony White from By-Product of Lead Smelting

Antimonial dust is a by-product of lead smelting and an important material for extracting antimony. A new pyrometallurgical process for producing antimony white from the antimonial dust is reported. The process mainly consists of three steps, which are reduction smelting, alkaline refining, and blowing oxidation. First, the reduction smelting of antimonial dust is carried out in an oxygen-rich bottom blow furnace to enrich antimony and lead in the crude alloy. The antimony and lead contents in the slag can thus be reduced to 2.8 wt.% and 0.1 wt.%, respectively. Second, the conventional method of alkaline refining is adopted to remove arsenic from the crude alloy, and arsenic content in the low-arsenic alloy could be decreased to 0.009 wt.%. Finally, the low-arsenic alloy is oxidized in a special oxidizing pan at 650°C by blowing compressed air or oxygen-rich air on the surface, during which qualified antimony white can be produced and collected in a bag house. The oxygen concentration and antimony content in the bottom alloy have a significant impact on production efficiency and product quality during blowing oxidation.     

B2O3—MgO—SiO2—Al2O3—CaO系渣组成对溶体物性的影响

用柱体旋转法测定了Ｂ_２Ｏ_３—ＭｇＯ—ＳｉＯ_２—Ａｌ２Ｏ_３—ＣａＯ系富硼镁渣的粘度及熔化性温度，用双柱联称法测定熔渣的密度及表面张力．实验结果表明：富硼镁渣的粘度及熔化性温度随渣中Ｂ_２Ｏ_３含量的增加而降低；当Ｂ_２Ｏ_３含量一定时，随渣中ＭｇＯ量及渣碱度的增加而增大．熔体的密度及表面张力随ＭｇＯ量增加或ＳｉＯ_２量减少而增大，分别为（２．５±０．５）ｔ·ｍ~（－３）和０．４－０．６Ｎ·ｍ~（－１）．     

新型环保除尘镁铁球在电炉冶炼造渣中的应用

介绍了太钢一钢厂电炉用除尘镁铁球团的研制以及它在电炉造渣中的应用,即对原本废弃不用的除尘红灰进行回收,制成性能良好的电炉造渣原料“镁铁球”加入炉中参与冶炼。当电炉冶炼氧化前期大幅脱磷时,随冷料一起配入镁铁球,可在熔化前期快速成渣,达到低温大幅脱磷的效果,从而保证在氧化期自如地控制电炉中钢水的终点碳,并大幅去除钢中有害夹杂物,净化钢液。     

Behavior of vanadium during reduction and smelting of vanadium titanomagnetite metallized pellets

The effects of CaO content, MgO content and smelting temperature on the vanadium behavior during the smelting of vanadium titanomagnetite metallized pellets were investigated. The thermodynamics of reduction and distribution of vanadium was analyzed and the high-temperature smelting experiments were carried out. The thermodynamic calculations show that the distribution ratio of vanadium between the slag and the hot metal decreases with the increments of CaO and MgO content in the slag as well as the increase of the smelting temperature. The smelting experiments demonstrate that the vanadium content in iron and the recovery rate of vanadium in pig iron increase as the CaO content, MgO content and smelting temperature increase, whereas the vanadium distribution ratio between the slag and iron tends to decrease. Moreover, the recovery rate of vanadium in pig iron has a rising trend with increasing the optical basicity of the slag. The addition of MgO in the slag to increase the slag optical basicity can not only improve the vanadium reduction but also promote the formation of magnesium-containing anosovite, which is beneficial to following titanium extraction.     

大功率密闭直流电弧炉冶炼钛渣烟气净化工艺研究

根据国内引进的第一台30MW密闭直流电弧炉钛渣生产线的工艺流程,对采用云南省钛铁矿冶炼钛渣过程中产生的烟气进行了气体及烟尘的流量、含量、化学成分等分析。由于产生的烟气具有温度高、含尘量大(1.75%~9.60%)、SO2含量低、CO含量高的特点,选择烟气净化设备时,除了处理能力要符合生产要求,还需要考虑粉尘粒径和烟气温度这两个因素,以实现烟气回收利用的目的。经过研究,烟气净化工艺首先对烟气进行直接水冷使烟气降温,然后选用德国进口涤气机对烟气进行精处理,除尘效率可以达到99.983%。处理净化后的烟气,热值高,气体性质稳定,净化后可安全用于无烟煤/钛渣干燥及渣包/铁包的烘烤,实现节能减排的目标;烟尘可以回收利用。     

连铸结晶器内卷渣过程的数学模型

基于功能原理和速度边界层理论,建立了一个数学模型来研究结晶器内渣金卷混机理,提出了引起界面卷渣的钢液临界流速和渣滴直径计算公式,并利用物理模型进行了验证。结果表明：钢液临界流速决于渣钢密度、粘度和它们之间的界面张力,在实际生产中,钢液临界流速为０．５－０．８ｍ／ｓ,产生的渣滴直径约为３ｍｍ。     

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针对含硼中碳钢铸坯角部裂纹问题,通过检测保护渣凝固液渣层硼含量发现钢中硼的质量分数为0.001 3%时,进入渣中B2O3的质量分数为0.74%,并测得原渣样和液渣样粘度分别为0.122、0.12Pa·s(1 300℃),认为钢中硼含量对保护渣性能影响较小,无需针对含硼钢设计特殊保护渣。对原中碳钢保护渣性能进行了优化,碱度(R)从1.23增加到1.27;1 300℃下粘度从0.165Pa·s降低到0.123Pa·s;1 350℃下熔速从22kg/h增加到27kg/h;熔点从1 085℃增加到1 155℃,铸坯角部裂纹得到了明显的控制。     

Resistance of High-Nickel,Heat-Resisting Alloys to Air and to Supercritical CO<Subscript>2</Subscript> at High Temperatures

The reduction behaviour of wustite-type iron oxide scale on a low-carbon, low-silicon steel by dissolved carbon in the steel at 650–900 °C under pure nitrogen was studied. It was found that dissoved carbon in the steel examined was able to react with the wustite scale on the surface, leading to reduction of this scale. It was also found that the scale reduction rate was the most rapid within 750–800 °C, followed by that at 700 °C and then at 850 °C, whereas the rates were essentially zero at 650 and 900 °C. Decarburization occurred to the steel as a result of scale reduction, and the degree of decarburization at 750–800 °C was also the most severe. The rate of scale–carbon reaction was primarily controlled by carbon diffusion through the decarburization layer as the calculated carbon permeability, defined as the product of carbon diffusivity and the carbon concentration difference across the decarburization layer, also reached its maximum within 750–800 °C. Scale reduction led to the formation of pores at the scale–steel interface as a result of volume shrinkage when wustite was reduced to iron, but the porosity volume was smaller than calculated at 800–850 °C, which could have an inhibiting effect on the scale–carbon reaction. The calculated volume of CO + CO₂ gases generated as a result of scale–carbon reactions was about 100 times the calculated porosity volume. It was believed that the wustite scale was permeable to CO and/or CO₂, allowing the much larger volume of CO and CO₂ gases to escape through the scale layer.     

含碳球团—铁浴熔融还原法关键技术的应用基础研究

系统研究了以非焦煤粉和铁精矿粉为基础的含碳球团－铁浴熔融还原新流程的关键技术。解决了冷固结含碳球团高温强度问题，提出了含碳球团自还原动力学模型，再氧化机理和提高球团预还原速度，抗氧公有力的技术措施和参数，研制出了具有高配碳量，高强度，高自还原速度，高预还原速度，高抗氧化能力的新型含碳球团。同时，研究了含碳球团在铁浴中熔化还原动力学参数，优化得到了控制还原速度，终还原率，熔渣中最低ＦｅＯ含量，泡沫渣     

叶片用超低碳不锈钢冶炼技术

介绍了我厂为冶炼三峡不锈钢叶片ZGOCr13Ni4Mo钢进行的设备改造,以及ZGOCr13Ni4Mo钢VOD(真空氧脱碳)冶炼工艺流程和试验结果等。     

高碳钢连铸保护渣的性能

为了研究高碳钢保护渣在连铸过程中的匹配性,对典型工业高碳钢保护渣的熔化、润湿、黏度、渣膜分布,以及传热性能进行研究。结果表明,4个高碳钢保护渣的开始熔化温度范围为1 110~1 129 ℃,润湿角范围为30.1°~37.8°,黏度范围为0.210~0.312 Pa·s,转折温度范围为1 046~1 130 ℃,渣膜的液态层比例为14.7%~18.9%。其中,1号高碳钢保护渣熔化温度较低(熔化区间1 110～1 345 ℃)、黏度较低(0.264 Pa·s)、渣膜液态层较高(比例为18.9%)、转折温度(1 059 ℃)和控热能力均适宜,表明该渣在高碳钢连铸结晶器中可以迅速熔化,形成足够的液态渣,并从弯月面渗入渣道,形成均匀的渣膜,从而润滑铸坯,避免黏结漏钢和裂纹等缺陷,保障高碳钢连铸的顺行。     

IF钢炼钢过程洁净度控制生产实践

涟钢通过优化转炉底吹、下渣控制、顶渣改质技术、缩短RH炉处理周期、严格控制RH炉吹氧量、稳定脱碳终点氧含量、提高一次加铝命中率、RH炉破真空到开浇镇静时间大于20 min,确保了夹杂物有充分的上浮时间,使得中间包钢水全氧低于2.5×10-5比例大于90%,IF钢夹杂降等量从2011年1.41%降低到目前0.15%,铝耗从2011年1.86 kg/t降低到目前的1.05 kg/t,钢水洁净度得到进一步改善。     

THE THEORETICAL REQUIREMENTS OF CARBON FOR REDUCTION AND HEAT SUPPLY IN BLAST-FURNACE SMELTING

提出修正一般文献中关于保証还原和热量供应的理論碳量消耗的图解。应用冶金原理上浮士体的理論对焦比进行計算,提出了保証热量供应的曲线。从图解推断有可能在适当的原料条件下,把焦比降到450公斤左右。     

缩短120 t顶底复吹转炉工艺时间的研究与实践

为提高转炉产能,有效降低成本消耗,实现降耗增效、降本增效、提质增效、提产增效,北营炼钢厂在现有设备工艺条件下,推进转炉工艺优化,通过提高供氧强度、优化复吹工艺、少渣冶炼等手段,实现了缩短转炉工艺时间及冶炼周期约5 min/炉,且部分技术指标达历史最好水平,其供氧强度、复吹碳氧积接近国内先进水平。