Thermodynamic and experimental study of high-temperature roasting of blast furnace gas ash for recovery of metallic zinc and iron

A high-temperature reduction roasting method was used to achieve metallic iron and zinc recovery from blast furnace gas ash(BFA).The reduction processes for Zn-containing and Fe-containing oxides were analyzed in detail by using ther-modynamic equilibrium calculation and the principle of minimum free energy.The results showed that the main reaction in the system is the reduction of ZnFe_(2)_(4)and iron oxides.Over the full temperature range,iron oxides were more easily reduced than zinc oxides.Regardless of the amount of CO contained in the system,the reduction of ZnO to Zn was difficult to proceed below the boiling point(906℃)of Zn.When the reduction temperature is below 906℃,the reduction process of zinc ferrate was ZnFe_(2)_(4)→ZnO;when the reduction temperature is above 906℃,its reduction process becomed ZnFe_(2)_(4)→ZnO→Zn(g).The metallization and dezincification rates of the BFA gradually increased with increasing reaction temperature.As the C/O ratio increased,the metallization and dezincification rates first increased and then decreased.The effect of reduction time on BFA reduction was similar to that of reaction temperature.

Present development of rolling reheating furnace technology in Shougang

By analyzing recent development of reheating furnace in Shougang,the direction of rolling reheating furnace is large type,high efficiency,lower pollution and automation etc.Many advanced technologies are integrated in new rolling reheating furnace such as working beam,regenerative combustion,evaporation cooling and hot loading and hot feeding etc.It shows that reheating furnace technology is upgraded.During the process of product structure adjustment in Shougang,because product heating quality is improved,energy-saving of reheating furnace should pay attention to aspects such as energy-saving of heating variety steel,equality of heating steel,heating system,oxidation loss and so on.This will offer reference for energy-saving of domestic and overseas reheating furnace technology.

Castables for Steel Rolling Reheating Furnace

1 Scope This standard specifies the classification, technical requirements, test methods, quality appraisal procedures, packing, marking, transportation, storage and quality certificate of castables for steel rolling reheating furnace.

High-temperature performance study of chromium-containing stuffing sand for ladles

High-temperature performance tests of chromium-containing stuffing sand for a steel ladle w ith different ratios w ere performed. A high-temperature simulation test furnace w as used to analyze the influence of the composition ratio of ladle filler sand and sintering time on the high-temperature compression resistance of chromium-containing stuffing sand in the temperature range of 1 500- 1 600 ℃. The results show that the refractoriness of ladle filler sand w as the low est（ only 1 610 ℃） w hen the composition ratio of chromite sand and silica sand w as 6∶ 4. M oreover,the high-temperature compression resistance w as high w hen the content of chromite sand w as at 70%; the resistance increased w ith increasing sintering time. When the sintering time w as extended at a temperature of 1 600 ℃,the high-temperature compression resistance of ladle filler sand first increased and then decreased after being overburnt.

安钢冷轧1550 mm连退炉内张力控制与分析

结合安钢冷轧连退机组实际工艺流程,以安钢冷轧1 550 mm连退机组退火炉为研究平台,分析与研究了其炉内带钢张力,这对于薄带钢高速运行低张控制优化具有一定指导意义,可实现冷轧连退薄带钢高效化生产。

台车式热处理炉热处理过程模拟与分析

热处理是轧辊产品生产过程中至关重要的环节,合理的热处理工艺对轧辊质量具有重要影响。采用数值模拟的方法,系统研究了热处理炉中轧辊不同摆放位置对炉内流场、温度场以及轧辊表面温度场的影响,为制定轧辊的精准热处理工艺,以及提高轧辊产品质量奠定基础。

免加热直接轧制技术送钢控制模型对直轧率的影响

针对棒线材的免加热直接轧制技术将铸坯从连铸机直接运输到轧机进行轧制,可完全取消传统加热炉,实现节能减排的目标。与传统棒线材轧制工艺相比,直轧率偏低是影响免加热直接轧制技术推广的因素之一。提出了一种新送钢控制模型,依据现场实际生产工艺参数,研究对比了先进先出模型(first in first out, FIFO)和所提控制模型的运行效果。结果显示,在四机四流连接一条轧线下,采用FIFO控制模型的直轧率为88.7%,与实测直轧率吻合较好,而采用所提控制模型可将直轧率提高到94.3%。同时还模拟研究了两种模型在五机五流连接一条轧线下的直轧率,结果显示使用FIFO控制模型、所提控制模型的直轧率分别为74.3%和81.7%。通过结果对比发现,送钢控制因素直接影响直轧率。另外,连铸机流数与轧机能力的匹配程度也是影响直轧率的重要因素之一。

热连轧加热炉控制系统及升温曲线的优化研究

为解决当前热连轧加热炉在实际生产中由于对温度控制精度不够而导致的轧制产品质量不好和能耗偏高的问题,在对热连轧加热炉进行综合概述的基础上,采用可兼容通讯模块对控制系统进行改造,对加热炉升温曲线进行优化。优化改造后,对在炉时间、装炉温度和能耗等指标进行综合评估,不仅提升了产品质量,而且降低了能耗。

3105B合金深冲锅胆料工艺研究

使用1003★1950倾斜式双驱动铝板带铸轧机,生产3种不同厚度铸轧板,均匀化退火,通过金相抛光及低倍组织检验,研究了坯料板厚对晶粒和力学性能的影响。结果表明,铸轧坯料板厚的不同对铝板力学性能和轧制性能有显著影响。

直用罩退炉烟气余热烘干脱脂冷轧板技术实践

针对罩式退火炉的高温烟气余热特点,提出了直用烟气余热烘干冷轧板技术。从烟尘特性入手分析烟气对冷轧板质量的影响,提出了烟气净化烘干工艺流程并确定了工艺参数。对工艺的经济性与节能效益进行分析,阐述该技术的应用效果。实践表明,烟气净化后直用烘干冷轧板技术安全可靠,节能效果好,可有效降低生产运行成本,提升企业经济效益。

冷轧板表面水淬网纹与黄斑缺陷分析

近几年,随着国家工业逐步向高端市场转型,对汽车板和家电板的需求量大大增加,对冷板质量提出了更高的要求。然而,邯宝冷轧厂的连续退火炉已跟不上市场对产品的要求,生产高端产品时会产出大量的带出品,带出品的缺陷主要有黄斑、网纹等。分析发现,这些缺陷集中在水淬段范围之内。通过对水淬段的设备以及生产方式进行分析,找出了产生黄斑和网纹缺陷的原因,进而对设备进行了优化改造,最终消除了带钢表面缺陷。

轧钢加热炉低温烟气脱硫脱硝控制工艺研究

为提高轧钢加热炉低温烟气脱硫脱硝的效率,且在低成本和能耗下增强处理效果,改善大气中二氧化硫与氮氧化合物污染问题,对轧钢加热炉低温烟气脱硫脱硝工艺进行了研究。详细分析脱硫脱硝工艺流程中的所涉及的关键参数,并采用模糊PID来完成对低温烟气脱硫脱硝工艺关键参数的自整定控制,输出最佳的关键参数,完成低成本和低能耗,高效的低温烟气脱硫脱硝。经过试验验证,该方法可以有效实现烟气脱硫脱硝,具有较高的处理效率,且综合能耗与成本均更低,应用后能够有效降低烟气中二氧化硫和氮氧化合物的浓度,增强脱硫脱硝效果。

原料钢坯氧化铁皮控制研究

热轧带钢和原料坯氧化铁皮的厚度对于提高钢产品表面质量、降低生产成本具有重要意义,但原料坯进入加热炉后,氧化铁皮逐渐脱落、堆积,会严重影响加热炉正常运行,若处理不当,还会造成产品表面缺陷。针对此问题,重点分析了原料钢坯氧化铁皮在生产中对加热炉的主要影响,并针对性地制定了优化钢产品化学成分、调整生产工艺参数、制作氧化铁皮清除装置等工艺优化措施,减少了热轧带钢中氧化铁皮的轧入。

Optimal control for spatial-temporal distributed nonlinear autoregressive with exogenous inputs correlation model of steel rolling reheating furnace: a coordinated time-sharing control approach

Accurate control of slab temperature and heating rate is an important significance to improve product performance and reduce carbon emissions for steel rolling reheating furnace(SRRF).Firstly,a spatial temporal distributed-nonlinear autoregressive with exogenous inputs correlation model(STD-NARXCM)to spatial temporal distributed-autoregressive with exogenous inputs correlation model(STD-ARXCM)in working point is established.Secondly,a new coordinated time-sharing control architecture in different time periods is proposed,which is along the length of the SRRF to improve the control performance.Thirdly,a hybrid control algorithm of expert-fuzzy is proposed to improve the dynamic of the temperature and the heating rate during time period 0 to t_(1).A hybrid control algorithm of expert-fuzzy-PID is proposed to enhance the control accuracy and the heating rate during time period t_(1) to t_(2).A hybrid control algorithm of expert-active disturbance rejection control(ADRC)is proposed to boost the anti-interference and the heating rate during time period t_(2) to t_(3).Finally,the experimental results show that the coordinated time-sharing algorithm can meet the process requirements,the maximum deviation of temperature value is 8-13.5℃.

基于BP神经网络的炉辊健康评估

炉辊是连续退火机组的重要设备,其健康状态直接影响带钢表面质量,有效评估炉辊的健康状态对于炉辊的健康维护计划具有重要意义。从某钢厂炉辊的历史数据出发,针对炉辊工作特性,提出了炉辊健康状态监测方案,设计了基于BP神经网络的炉辊健康评估方法,实现了对炉辊正常、轻微退化、严重退化和故障4个等级健康状态的识别,达到了指导炉辊有效健康评估和更换维护的目的,具有良好工程实用性。

湿法除尘在烧结混料系统上的应用实践

在烧结生产过程中,烧结一次混合机、二次混合机是烧结生产工艺中必不可少的重要设备,它承担着对混合料进行润湿、混均及制粒的重任,是当前上料系统普遍采用的皮带机-漏斗给料方式,使混合料的水分、粒度、料温及混合料的成分均匀分布并制粒,为烧结机提供适宜的混合料。但在混合制粒过程中,产生大量的蒸汽和粉尘,现场环境较差。本文主要针对天津市新天钢联合特钢有限公司烧结厂两台230平米烧结机在一混、二混生产过程中存在的问题进行论述,并针对此项问题展开攻关,提出解决方案,彻底改善现场环境,实现超低排放。

Flow behavior of high-temperature flue gas in the heat transfer chamber of a pilot-scale coal-water slurry combustion furnace

The flow characteristics of high-temperature flue gas are important in the heat transfer of coal-water slurry（CWS） combustion furnaces.The flow field of a 250 kg/h vertical-type slag tap cyclone furnace was non-intrusively investigated,using two-dimensional particle-image velocimetry（2D PIV）.The method was verified using traceable fly ash particles in high-temperature flue gas.The flow field of the flue gas was analyzed with a time-averaged method,based on which the effects of excess air ratio and loading were investigated.The flue gas separated by a gas separator maintained good rigidity near the furnace wall,rather than eroding the heating surface.Numerical simulations validated the reliability of PIV under the actual circumstances within the furnace.This study provides guidelines for applying 2D PIV in analyzing flue gas in thermal test boilers.

连续退火炉张力波动控制研究

根据连续退火炉的张力控制原理,对退火炉的张力波动现状进行分析,制订系统的张力波动排查方案,利用检修时机对退火炉设备开展排查,发现缓冷段炉顶辊炉辊轴头变形导致了带钢张力波动;通过分析炉辊变形与退火炉张力波动情况,以及带钢张力波动与带钢表面周期性硌痕的对应关系,发现张力波动引起的带钢抖动剐蹭到缓冷段风管,从而导致铁屑黏附到炉辊表面,影响了产品质量的稳定。

High-temperature oxidation behavior of modified 4Al alumina-forming austenitic steel: Effect of cold rolling

The oxidation behavior and mechanism of as-received and 30 % cold-rolled alumina-forming austenitic(AFA) steel were investigated in dry air at 700℃.The results show that the mass gain per unit area curves of as-received and 30 % cold-rolled steels subject to near-parabolic law before 100 h oxidation time.Two samples both show higher high-temperature oxidation resistance due to the formation of dense Al_(2)O_(3) oxide scale.Gradual spallation of outer scale results in the formation of continuous and dense alumina scale.Dislocations can act as short-circuit diffusion channel for the diffusion of Al from alloy matrix to surface,and also provide nucleation sites for B2-NiAl phase,which ensure the continuous formation of Al_(2)O_(3) scale.

基于BP神经网络的炉辊传动部故障诊断

为了实现连续退火炉炉辊传动部的故障精准定位,采用BP神经网络诊断炉辊传动部故障。按照采样周期采集炉辊传动部4个测点的振动信号并提取时域指标;构建基于BP神经网络的炉辊传动部的故障诊断模型;将提取的时域指标制作数据集,构建训练模型并验证。实验结果表明:基于BP神经网络的炉辊传动部故障诊断准确率达到了98.11%,有效实现了炉辊传动部故障的精准定位,为炉辊传动部的故障分析提供了思路。