复吹转炉多功能法脱磷工艺

在不新增设备的前提下,通过优化转炉冶炼工艺,使用复吹转炉多功能法进行铁水脱磷,提高转炉脱磷率.根据现有转炉设备条件,通过热力学计算确定转炉前期脱磷温度范围,并在现场实验中掌握好倒渣时机、渣碱度、加料量和出钢温度,确定最佳脱磷工艺.分析实验结果,与常规冶炼相比,该脱磷工艺用原料量少,脱磷率稳定,且高达90%以上,在提高钢水质量的同时也降低了生产成本.     

转炉留渣脱磷工艺实践

介绍了某炼钢厂40t顶吹转炉的留渣操作工艺。从转炉脱磷的热力学和动力学理论两方面进行了分析,并针对性地制定了转炉吹炼过程去磷的有效措施,包括采用转炉留渣操作提高前期去磷效果、提高炉渣碱度等。实践证明,实施留渣操作对转炉冶炼时的脱磷十分有利,脱磷率由80.1%提高到89.9%,还可以降低石灰及钢铁料消耗,提高炉龄,取得了显著的经济效益。     

转炉留渣-双渣操作前期脱磷影响因素

为实现转炉高效脱磷同时减少渣料(主要是石灰)消耗,对国内某钢厂的80 t转炉进行了留渣-双渣操作试验。通过引入经验公式对前期脱磷的影响因素进行了热力学计算,并与现场实验结果进行了对比,得出转炉吹炼前期脱磷较佳的工艺条件:炉渣碱度R控制在1.2~1.8左右,一次倒渣温度控制在1 325~1 355℃,渣中FeO质量分数控制在15~17%。统计生产数据表明,留渣-双渣操作比单渣操作,石灰加入量每吨钢减少6.9 kg。     

基于多功能转炉炼钢法的连续循环冶炼过程

为了研究脱碳渣在脱磷期的重新利用,基于多功能转炉炼钢法进行连续循环冶炼实验.实验发现：脱磷阶段渣中较低的FeO含量、吹炼5 min左右,[ C]≥2.8%的条件下,可实现转炉熔池内铁液[ P]≤0.025%的脱磷效果,并对低( FeO)含量炉渣的脱磷可行性进行热力学计算;随着循环的进行,石灰加入量逐渐降低,由65 kg·t-1降低至31 kg·t-1,转炉冶炼终点钢水[ P]量由0.018%降低至0.005%,2~4炉后达到平衡状态;在循环过程中,脱磷阶段结束倒出炉渣60~80 kg·t-1,整个循环结束一次性倒出剩余全部炉渣120~130 kg·t-1,平均渣量为83 kg·t-1左右,较普通工艺的120 kg·t-1渣量有大幅度减少.     

210吨转炉脱磷工艺探讨

本文根据济钢210吨转炉脱磷情况,主要从转炉脱磷的理论分析入手,对冶炼过程中前期温度、炉渣碱度、渣中(FeO)、转炉底吹效果等对终点磷的影响及回磷的原因、影响因素及防范措施等进行了探讨,同时本文指出应控制的参数:炉渣碱度、渣中(FeO)、终点温度在合理范围内,并重视钢水回磷问题。     

京唐公司转炉双联冶炼工艺及技术指标

阐述了京唐公司转炉双联工艺及其优势,重点就转炉双联法与常规冶炼主要技术指标进行了对比分析,分析结果显示：采用转炉双联冶炼法时脱磷率为92.86%,采用常规冶炼法转炉脱磷率为88.4%,转炉双联工艺脱磷效果明显。脱磷炉终渣中平均TFe含量是8.27%,脱碳炉终渣中平均TFe含量是18.92%,常规转炉终渣中平均TFe含量是18.98%,转炉双联冶炼过程不仅铁损低,而且金属料消耗少。辅原料消耗上转炉双联法白灰和轻烧白云石的用量比传统冶炼法分别减少9.7 g/t钢、9.3 g/t钢。转炉双联法和常规冶炼法终点钢水平均碳氧积分别为0.0023和0.0024,控制水平较好。     

高磷铁水脱磷渣枸溶性

参照实际转炉脱磷炉渣,配制了不同F、P2O5、FeO和MgO含量及碱度的渣样,用化学分析方法测试了不同组分对渣中磷的枸溶率的影响规律.结果表明:当脱磷渣中含有F时,P主要与F形成氟磷灰石,使得磷的枸溶率随渣中F含量的升高而急剧降低,当不含氟时枸溶率可达92.5%,当氟质量分数达到0.5%时枸溶率已降低到50%以下;随碱度增加,由于渣中Ca2+含量增加,破坏了硅氧网络结构,使得枸溶率有所上升;渣中MgO含量升高,由于Mg2+在熔融冷却过程中会抑制β--Ca3(PO4)2晶体的析出,而β--Ca3(PO4)2中磷不易为质量分数为2%的柠檬酸液溶出,而使枸溶率有所升高;随渣中P2O5含量升高,由于P5+与O2-形成络离子,P5+位于O2-密集形成的间隙中,不易溶出,使得枸溶率有所下降;渣中FeOn升高,枸溶率随之降低.     

转炉冶炼 CaO-SiO2-FeO 渣系中磷的行为

回归推导出渣系中磷酸盐容量对数与炉渣光学碱度和温度的关系表达式,通过回归公式绘制出 CaO-SiO2-FeO(10% MgO)渣系的等磷酸盐容量图,分析了转炉终渣、终点成分及温度对钢中磷含量的影响情况.当熔渣磷酸盐容量一定时,随着转炉终点碳含量降低,渣/钢间磷分配比增加;相同终点碳含量时,随着熔渣磷酸盐容量增加,渣/钢间磷分配比增加;转炉终点碳质量分数控制在0.03%～0.04%,炉渣碱度大于3.5,渣中 FeO 质量分数低于18%,渣中 P2O5质量分数低于2%,有利于获得终点磷质量分数在0.008%以内的钢水.     

转炉利用石灰石造渣炼钢的试验研究

基于对石灰石分解机理的分析,研究了炼钢过程中利用石灰石代替石灰进行造渣时炉内富余热量的变化,发现当采用全部石灰进行冶炼时,铁水加入比(质量分数)可达到86.1%左右,随着石灰石加入量的增加,废钢比降低,吨钢富余热量减少,石灰加入量降低.若全部采用石灰石进行造渣,铁水比最高可达到97.0%.在此基础上,利用60 t转炉研究了炼钢过程采用石灰石完全代替石灰进行造渣炼钢的冶金效果.实验发现：与采用石灰造渣炼钢相比,当采用石灰石进行造渣炼钢时,吹炼至4 min时的炉渣TFe质量分数为21.87%,碱度为1.22;随着吹炼时间增加,炉渣TFe含量降低,碱度上升至3.0以上.炼钢过程脱磷更加稳定且脱磷率提高了2.6%;平均终渣碱度为3.52,能满足冶炼的脱磷要求;渣量大幅度降低,从而降低了钢铁料消耗;吹炼时间略有延长,终点熔池温度基本保持不变.研究结果为调整炉料结构、降低生产成本提供了新的方法和思路.     

转炉冶炼CaO-SiO2-FeO渣系中磷的行为

回归推导出渣系中磷酸盐容量对数与炉渣光学碱度和温度的关系表达式,通过回归公式绘制出CaO-SiO2-FeO(10%MgO)渣系的等磷酸盐容量图,分析了转炉终渣、终点成分及温度对钢中磷含量的影响情况.当熔渣磷酸盐容量一定时,随着转炉终点碳含量降低,渣/钢间磷分配比增加;相同终点碳含量时,随着熔渣磷酸盐容量增加,渣/钢间磷分配比增加;转炉终点碳质量分数控制在0.03%～0.04%,炉渣碱度大于3.5,渣中FeO质量分数低于18%,渣中P2O5质量分数低于2%,有利于获得终点磷质量分数在0.008%以内的钢水.     

Phosphate enrichment mechanism in CaO–SiO2–FeO–Fe2O3–P2O5 steelmaking slags with lower binary basicity

The addition of silica to steelmaking slags to decrease the binary basicity can promote phosphate enrichment in quenched slag samples. In this study, we experimentally investigated phosphate enrichment behavior in CaO–SiO₂–FeO–Fe₂O₃–P₂O₅ slags with a P₂O₅ content of 5.00% and the binary basicity B ranging from 1.0 to 2.0, where the (%Fe_tO)/(%CaO) mass percentage ratio was maintained at 0.955. The experimental results are explained by the defined enrichment degree R_C2S-C3P of solid solution 2CaO·SiO₂–3CaO·P₂O₅ (C₂S–C₃P), where R_C2S-C3P is a component of the developed ion and molecule coexistence theory (IMCT)–N_i model for calculating the mass action concentrations N_i of structural units in the slags on the basis of the IMCT. The asymmetrically inverse V-shaped relation between phosphate enrichment and binary basicity B was observed to be correlated in the slags under applied two-stage cooling conditions. The maximum content of P₂O₅ in the C₂S–C₃P solid solution reached approximately 30.0% when the binary basicity B was controlled at 1.3.     

超低碳钢顶渣氧化性对钢液洁净度的影响

为探究降低顶渣氧化性对改善超低碳钢钢液洁净度的影响,在转炉终点至中间包过程中,在多位置取炉渣和钢水试样,分别进行炉渣氧化性、钢液成分和夹杂物分析.实验结果表明:转炉出钢后通过对顶渣改质,渣中T.Fe由转炉终点的19.18％降至RH进站时的4.68％,顶渣氧化性降低明显.渣中T.Fe降低导致钢中[O]的降低,T.Fe较低的炉次平均吹氧量较大,使得铝脱氧前钢中[O]较高.RH结束渣T.Fe与夹杂物数量呈线性关系,T.Fe越低夹杂物数量越少,同时RH结束后夹杂物数量与铝脱氧前钢中[O]无必然关系.顶渣(CaO)/(Al2O3)会影响其吸收Al2O3夹杂物的能力,(CaO)/(Al2 O3)控制不合理的炉次,其夹杂物数量也较多.通过降低顶渣氧化性,热轧板卷缺陷率得到明显降低.     

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.     

复吹转炉锰矿直接合金化热力学模型研究

基于某钢厂铁水、废钢和造渣料等的成分得出转炉炼钢的渣量计算模型,根据热力学原理得出锰的收得率和终点锰含量的预报模型。对模型研究结果表明,提高终点出钢温度、渣碱度、锰矿品位和铁水Mn含量,降低终渣含量及渣中FeO含量,可显著提高Mn的收得率和终点Mn含量。     

基于粗糙集的转炉炼钢知识发现模型

针对转炉炼钢知识发现的特点,采用粗糙集理论进行分析,应用数据清洗、标准化及离散等方式对转炉炼钢生产数据进行预处理,以炼钢生产的主要影响因素作为知识发现的条件属性,以转炉冶炼终点控制目标作为知识发现的决策属性,建立了基于粗糙集方法的转炉炼钢知识发现模型,实现转炉炼钢生产知识的自动发现、获取和规则提取。以转炉冶炼终点钢水温度的变化规律做为知识发现的决策属性,采用210 t转炉炼钢实际生产数据进行模型的应用测试,结果表明提取出的铁水硅含量、铁矿石质量、氧气消耗量等影响因素对转炉冶炼钢水终点温度存在重要影响,且模型提取出的转炉炼钢终点钢水温度知识规则与现行转炉炼钢现场的变化规律一致,证明基于粗糙集方法的转炉炼钢知识发现模型的有效性。     

精炼渣成分与轴承钢夹杂物类型关系热力学分析

针对轴承钢中钙铝酸盐大型夹杂物的控制问题,通过计算GCr15轴承钢中尖晶石MgO·Al2 O3、钙的铝酸盐CaO·6Al2 O3夹杂物生成热力学,分析精炼渣成分与夹杂物类型之间的定量关系.结果表明：当钢水中含有质量分数0.10×10-6的溶解钙[Ca]时,只要溶解镁[Mg]质量分数小于10×10-6,MgO·Al2O3就会被[Ca]还原成 CaO·6Al2O3;当精炼渣碱度为7.04,(MgO)质量分数为1.38%时,钢水中溶解[Mg]质量分数比临界[Mg]质量分数低56%,夹杂物以尺寸大于10μm的CaO-Al2O3系复合夹杂为主;当精炼渣碱度为3.75,(MgO)质量分数3.14%时,钢水中溶解[Mg]质量分数比临界[Mg]质量分数低14%,夹杂物以尺寸小于8μm的MnS包裹MgO·Al2 O3复合夹杂为主;当精炼渣钙铝比C/A为1.8~2.0时,控制精炼渣碱度R为4.5~5.5,(MgO)质量分数为3%~5%,即能使钢中MgO·Al2O3保持稳定而不转变为CaO·6Al2O3.     

Activity coefficients of NiO and CoO in CaO-Al2O3-SiO2 slag and their application to the recycling of Ni-Co-Fe-based end-of-life superalloys via remelting

To design optimal pyrometallurgical processes for nickel and cobalt recycling, and more particularly for the end-of-life process of Ni–Co–Fe-based end-of-life (EoL) superalloys, knowledge of their activity coefficients in slags is essential. In this study, the activity coeffi-cients of NiO and CoO in CaO–Al2O3–SiO2 slag, a candidate slag used for the EoL superalloy remelting process, were measured using gas/slag/metal equilibrium experiments. These activity coefficients were then used to consider the recycling efficiency of nickel and cobalt by remelting EoL superalloys using CaO–Al2O3–SiO2 slag. The activity coefficients of NiO and CoO in CaO–Al2O3–SiO2 slag both show a positive deviation from Raoult’s law, with values that vary from 1 to 5 depending on the change in basicity. The activity coefficients of NiO and CoO peak in the slag with a composition near B = (%CaO)/(%SiO2) = 1, whereB is the basicity. We observed that controlling the slag composition at approximatelyB = 1 effectively reduces the cobalt and nickel oxidation losses and promotes the oxidation removal of iron during the remelting process of EoL superalloys.     

含钛高炉渣活度模型的建立及热力学分析

根据分子离子共存理论,建立了CaO-SiO2-MgO-Al2O3-TiO2含钛高炉渣活度模型,模型计算结果与实验测定结果吻合较好.利用该模型并结合相图计算分析了碱度和w(TiO2)对含钛高炉渣主要组元活度的影响.结果表明,含钛高炉渣中钛的主要赋存相是CaO·TiO2,1500℃时典型含钛高炉渣中CaO·TiO2的活度为0.18.随着碱度和w(TiO2)增加,CaO·TiO2活度先增后减.当碱度区间在1.08~3.08,w(TiO2)在26%~43%的条件下,有利于CaO·TiO2活度的增加,促进钛组分在钙钛矿中富集.CaO·TiO2活度最大值所需碱度随TiO2含量的增加而增加,当含钛高炉渣中w(TiO2)为20%~28%时碱度为1.34~1.63,对促进钛在钙钛矿中的富集是有利的.     

转炉炉渣气化脱硫动力学

研究了转炉炉渣的气化脱硫动力学,着重考察了熔渣温度、∑ＦｅＯ含量、碱度以及气氛对气化脱硫速度的影响,对气态脱硫反应的机理和反应速度的限制性环节进行了分析和讨论。