青钢降低高炉槽下烧结返矿率生产实践

2013年初青钢高炉槽下烧结返矿率达210 kg/t,铁水成本明显增加。为此,青钢炼铁公司从配矿结构、烧结矿碱度及熔剂质量、料层厚度、点火温度、烧结工艺、筛分系统等方面进行改进,采取优化配矿结构、适当提高烧结矿碱度和稳定熔剂质量、提高点火温度、改进烧结生产工艺、加强高炉槽下筛分管理等措施,使烧结矿强度提高了5%,烧结返矿率下降了17%,年降低费用1 179.36万元。     

优化配矿结构对烧结矿冶金性能的影响

针对永锋钢铁公司烧结原料结构, 明确烧结目标, 进行烧结杯优化配矿实验, 以达到提高烧结矿成矿率、利用系数、成品矿品位、转鼓强度以及降低其返矿率的目的.实验运用扫描电镜观察成品矿形貌显微结构; 用成品烧结矿还原实验的检测数据, 探究优化配矿对成品烧结矿还原性能的影响; 并对比现场烧结配矿前、后的各项指标.实验结果表明:在现场烧结配矿条件下(在将巴混配比提高6 %, 燃料比降低至4 %, 烧结负压为11 kPa)通过优化配矿, 成品烧结矿转鼓强度可达到70.93 %, 成品率及利用系数分别为84.44 %、1.77 (t/m2h), 烧结矿品位为53.7 %, 还原度高达83.5 %, 可以保证高炉稳定生产.      

降低高钛型钒钛精矿烧结返矿率实践

针对高钛型钒钛磁铁精矿的原料特点，通过工艺参数优化、烧结矿成分的合理控制，成品矿运输及筛分系统采用花格子衬板与阶梯漏子，降低皮带转速，高炉沟下筛增加缓冲溢流溜槽，缩小筛孔孔径，高炉回收使用小粒级烧结矿等技术措施，在物料条件变差状况下，实现了降低高钛型钒钛精矿烧结的返矿比例，对优化高炉炉料结构发挥了极大的作用。     

首钢京唐低硅低镁烧结技术的研究与应用

为了进一步改善5 500m~3特大型高炉精料入炉水平,首钢京唐炼铁作业部在停配白云石熔剂实现自然镁烧结的基础上,结合相关烧结杯试验做了微观组织结构研究。根据生产实际,通过采取优化配矿结构以及调整过程控制参数等措施,逐步降低烧结矿SiO_2与MgO质量分数生产低硅低镁烧结矿。通过低硅低镁烧结技术的应用,首钢京唐炼铁作业部在改善烧结矿品位稳定强度、粒度的基础上保证了入炉精料水平,并取得了较好的效果,为首钢京唐5 500m~3特大型高炉提高综合入炉品位、降低渣比以及喷煤降焦创造了良好的原料条件。     

基于低成本炼铁过程控制的研究实践

新冶钢“实施低成本”战略以来,铁前系统紧紧围绕公司生产要求,在外部条件劣化的背景下,始终围绕高炉的稳定顺行为基本方针,不断优化原、烧系统配矿方案;高炉通过加强原燃料管理,不断优化炉料和燃料结构,提高烧结矿、块矿和焦丁比例,不断优化高炉操作制度、提高煤比和富氧率,实现了高炉合理的煤气流分布和较高的煤气利用率,保持了高炉的长期稳定顺行;烧结固体燃耗、高炉燃料比等技术经济指标及工序制造成本不断降低,基本达到了经济炼铁的目标。     

降低烧结矿返矿率攻关实践

通过采取改善烧结矿原料质量,优化原料结构,加强成品筛分及高炉槽下筛分管理,提高料层厚度,增加压料装置,返矿回用炼钢等一系列攻关措施,宣钢烧结矿返矿率降低了3.64个百分点,低于行业平均水平以下,达到了预期的攻关目标。     

红钢降低高炉槽下返矿率的实践

针对红钢高炉槽下返矿率较高的问题,分析了影响高炉槽下返矿率的因素。由于红钢使用的本地铁矿粉种类多、烧结性能差,配加一定量的进口粉矿、提高烧结矿碱度和适当降低烧结矿中MgO含量,可改善烧结矿矿相及粒度组成,提高烧结矿的转鼓指数,为降低高炉返矿率创造条件。通过提高烧结料层厚度、完善装料及供料制度、强化高炉槽下筛筛板维护等措施,可使高炉返矿率降低5.95%。     

降低武钢烧结返矿率的生产实践

武钢烧结矿返矿率一直较高,造成烧结能耗和加工成本的增加。为降低烧结返矿率,采取了适当提高烧结矿FeO含量、调整烧结点火温度、强化制粒、调整烧结筛网尺寸等一系列措施。2014年第1季度,炼铁厂全厂烧结返矿率降至11.5%,较2011年全年平均值下降5.9%,有效提高了烧结产量,在控制炼铁成本上取得了实效。     

MgO对烧结矿与高炉渣冶炼性能及工艺参数影响的试验

MgO是高炉渣的重要成分,渣中含有一定的MgO可降低炉渣粘度,提高炉渣流动性,提高还原性以及软化和熔化温度而改善冶金性能;烧结矿含有一定数量的MgO,可降低低温还原粉化性改善高炉透气性。工业试验表明,目前条件下攀钢烧结矿提高MgO 0.2%左右,矿相结构与矿物组成改善,强度提高0.10%左右,低温还原粉化率由66.03%降低到64.33%,但还原度由84.46%下降到84.13%,烧结矿粒度约有偏差。高炉渣中MgO质量分数提高0.35%达到7.8%~8.0%,炉渣熔化性温度与粘度下降,炉渣流动性由115 mm提高到170 mm,铁损由7.09%降低到5.15%,校正后产量下降18 t/d,但综合焦比下降了6.57 kg/t,节焦效果显著,同时烧结与高炉的工艺参数得到优化。     

不同厚度和不同部位烧结矿质量指标变化规律

通过对700、850、1 000 mm 3个料层厚度进行相应的石英杯烧结试验,研究得出随着料层厚度增加烧结成 品率逐渐增加,烧结矿转鼓指数逐渐升高,成品烧结矿的粒度组成逐渐变好,烧结固体燃耗降低;但垂直烧结速度 显著变慢,烧结利用系数降低。对3个料层厚度进行上、中、下3层的解剖研究结果表明,对于同一解剖层的烧结 矿,3个料层厚度的烧结成品率和转鼓指数大小顺序均为700 mm<850 mm<1 000 mm,同一料层厚度的烧结矿转 鼓强度指标是上层<下层<中层,平均粒度大小是上层<中层<下层。通过矿相分析得出同一料层厚度赤铁矿和 铁酸钙质量分数是上层<中层<下层,而磁铁矿质量分数是上层>中层>下层,3个料层厚度的赤铁矿和铁酸钙质 量分数依次是700 mm<850 mm<1 000 mm。     

Influence of Coating Granulation Process on Iron Ore Sinter Quality and Productivity

For better blast furnace performance, there has always been a need for better quality raw materials like sinter, lump ore, and pellets. Among these raw materials the usage of sinter in blast furnace is at higher side compared to other iron bearing materials. As the quality of sinter product improves, its usage in blast furnaces also increases. Iron ore fines are the main source for sinter making. To improve the sinter properties it is necessary to provide good quality of iron ore fines. Due to depletion of high grade iron ore resources, goethite and limonitic ore content in iron ore fines is expected to increase gradually. Usually limonitic and goethite ore are associated with higher alumina and LOI. The conventional sintering process is one of the well established processes for high quality hematite ore. It does not fully respond to the low grade iron ore associated with goethite and limonite. This has led to deterioration in sinter properties and productivity. In recent years the improvement in the quasi‐particle structure with the granulation process is an effective method for improving sinter quality and productivity. To improve the sinter quality and productivity for low grade iron ore fines, different granulation processes like the conventional one, and other two advanced granulation processes like coke breeze, and flux & coke breeze coating granulation were studied in detail by conducting laboratory pot grate sintering experiments. From the test results it was found that sinter productivity, physical and metallurgical properties of the sinter improved with flux & coke breeze coating granulation process compared to conventional and coke breeze coating granulation process. Proper selection of the granulation time is very important to achieve the desired sinter properties. In the present work detailed laboratory experiments have been carried out by varying the coating time from 30s to 110s to study the influence of flux & coke breeze coating granulation time on mineralogy, productivity, physical, and metallurgical properties of sinter. With a coating granulation time of 50s, higher productivity, higher yield, and stronger sinter (higher T.I) with lower RDI and ‐5mm size sinter were achieved.     

承德钒钛磁铁矿低碱度烧结试验研究

通过烧结杯试验研究了承德钒钛磁铁矿的低碱度烧结过程和烧结矿质量,探讨了低碱度钒钛烧结矿替代球团的可行性。结果表明：与高碱度钒钛烧结矿相比,低碱度钒钛烧结矿的成品率高、强度好、低温还原粉化性能好,可以满足高炉冶炼要求。但其垂直烧结速度慢,w（FeO）高。碱度控制在0.8,配碳量控制在3.4%～3.6%,配加20%的澳矿粉可以取得较好效果。     

Influence of Alumina on Iron Ore Sinter Properties and Productivity in the Conventional and Selective Granulation Sintering Process

Iron ore sinter constitutes a major proportion of blast furnace burden. Hence, its quality and consistency have a significant impact on blast furnace performance. Iron ore fines are the main source for sinter, and the chemical composition of the iron ore fines, together with the thermal conditions that blends are subjected to, plays an important role in forming the primary melt during the sintering process and accordingly determines the sinter structure and quality. Therefore, considerable importance has been placed on the chemical composition and consistency of iron ore fines, particularly in terms of alumina content. Due to depletion of high grade iron ore resources, alumina content in the iron ore fines is expected to increase gradually. Ore with higher alumina content is usually expected to be detrimental in forming the sinter matrix, if sintered alone, due to the low reactivity of alumina bearing minerals and the high viscosity of primary melts. The selective granulation process is a new sintering process for high alumina iron ore fines, and can eliminate the adverse effects of ‘hard to sinter’ or ‘unsuitable – for ironmaking’ ores. In the present work laboratory sintering experiments have been carried out with iron ore fines of different alumina level (2.00 to 5.46 mass‐%) to know the influence of alumina on mineralogy, productivity, physical and metallurgical properties of sinter prepared by the conventional and the selective granulation process. With increasing alumina content in sinter of both the conventional and selective granulation process, the fractions of hematite and of silico‐ferrites of calcium and alumina (SFCA) as well as the pore phase increased whereas the magnetite and silicate phases decreased. With increase in alumina content sinter productivity and tumbler index (T.I.) decreased, and metallurgical properties like sinter RDI and reducibility improved. However, sinter of the selective granulation process showed better results compared to the conventional process.     

Improvement of sintering performance of sinter mixtures containing high ratio of specularite fines

Although specularite fines possess high iron grade and low impurities, their granulation performance was poor so that the ratio of specularite fines is kept below 20% in sinter ore blends because of low permeability and productivity and weak strength. In order to increase its ratio in sintering, binders were used to improve the granulation performance of sinter blends containing high ratio of specularite fines in sintering pot test. Results show that cold permeability of the sintering bed increases by 19. 05% by adding 0. 65mass% bentonite or by 27. 98% by 0. 55mass% BF composite binder respectively when 36 mass% specularite fines are proportioned in sinter blends. In addition, the hot permeability is also improved by adding bentonite or BF composite binder, respectively, resulting in an increase in the productivity of 11. 67% and 7. 50% as well as an decrease in solid fuel consumption of 2. 82kg/t and 4. 01kg/t, respectively, while the tumble index, chemical composition and metallurgical performance meet the requirement of blast furnace. So using suitable binders is one of effective ways to improve the granulation and sintering performance of sinter ore blends comprising high ratio of specularite fines.     

库粉在烧结生产中的应用

库粉具有含铁品位高、含SiO2和Al2O3低、价格低等特点，为了充分利用库粉，针对其粘性差、含结晶水影响烧结料层透气性的问题，进行了优化配料结构和烧结工艺参数的生产试验。结果表明，在保证烧结矿产量、质量的基础上，可以配加12％库粉，既满足了高炉的需要，又可降低原料成本。     

达钢高炉原料冶金性能研究

针对四川迭州钢铁集团有限责任公司的高炉失常，全面检测了高炉原料的冶金性能，提出烧结矿的低温还原粉化是导致高炉失常的主要原因。在采取措施改善烧结矿质量，使高炉恢复正常生产后．又对烧结矿的冶金性能进行了研究。     

Development of fluxed micropellets for sintering utilising iron oxide waste fines

Abstract

Ultrafine iron oxide wastes such as slime, blue dust and Linz–Donawitz (LD) converter sludge have very limited use in sintering of iron ore due to their excessive fineness (?50 μm). Pelletisation of these ultrafine materials for use in blast furnace involves high temperature curing, which is a highly energy intensive process. Briquetting of LD sludge requires costly binders and contains high moisture, which creates problem at high temperature of the downstream process. In order to alleviate these problems, the current study has developed a process for preparing micropellets of waste iron oxide fines (2–6 mm size) without using any binder. The strength of the micropellet has been increased by a novel CO₂ treatment process at room temperature. Developed micropellets exhibit very suitable drop strength (125 Nos), tumbler properties and cold compressive strength (～9 kg/pellet) to withstand cold handling. Low lime containing micropellets have the possibility of being used as a mixed material in usual sinter making, and high lime containing micropellets may be exploited for making super fluxed sinter that can be used as synthetic flux in the basic oxygen furnace process towards the formation of low melting oxidising slag at the early stage of blow.     

氧化铝对铁矿石烧结质量和生产率的影响(英文)

烧结矿是现代高炉生产的主要含铁原料。合理控制入炉烧结矿的理化性能与冶金性能对高炉生产和稳定操作是很必要的。铁矿粉是烧结矿的主要原料,其化学成分和烧结料层内的热量条件在烧结过程中起着重要的作用。化学成分等参数也决定着烧结矿矿相结构和质量。由于含氧化铝原料的低反应性及其液相的高粘性,因此在人们的预料中高铝矿石对烧结矿结构组成的影响并不好。烧结混合料中的氧化铝在同化过程中需要消耗大量热量,延迟烧结过程。在确保高炉渣的流动性方面,氧化铝也需要消耗较大热量。不论是烧结还是高炉的生产实绩均表明,氧化铝是有害的。一般而言,高含铁量与低脉石的印度矿与其他矿石的不同特点就是氧化铝含量高。由于高品味铁矿石的消耗殆尽,使用可利用的烧结原料成为生产必需。因此,必须要掌握氧化铝的作用及其对烧结矿质量和生产过程的影响。实验室完成了不同氧化铝含量水平(2.00%～5.46%)的实验,可从中了解氧化铝在烧结矿矿物学、生产率、物理性能和冶金性能方面的影响。随着烧结矿中氧化铝含量的增加,残存赤铁矿、复合铁酸钙(SFCA)和孔隙率增加,而磁铁矿和硅酸盐比例下降。烧结生产率和烧结矿转鼓强度(TI)随着氧化铝含量上升而下降,反映烧结矿冶金性能的诸如低温还原粉化率(RDI)和还原率(RI)提高。     

烧结工艺优化的试验研究

针对湘钢采用高铁低硅烧结的特点,虽然提高了入炉烧结矿品位,但会使烧结矿强度、粒度、冶金性能等明显变差.采取添加蛇纹石的试验和生产,结果表明:烧结矿的SiO2含量略有提高,但改善了高铁低硅烧结矿中液相少、强度差的状况,使返矿率下降,固体燃耗量降低,烧结矿的还原性和软熔性能得到改善.针对湘钢高炉渣Al2O3含量高的实际情况,解决增加MgO会影响烧结矿强度的问题;工业试验表明:用轻烧白云石部分代替白云石对烧结矿的产量没有明显的影响,转鼓强度稍有提高,固体燃耗明显下降,高炉利用系数提高,焦比下降,炉渣流动性好.在降低烧结矿低温还原粉化率方面,喷洒约3?Cl2溶液是非常有效的.     

莱钢烧结、高炉锌的分布及平衡研究

对莱钢型钢区域的烧结、高炉进行了系统的锌分布及平衡研究。结果表明,265m2烧结机的锌金属带入量为0.88kg/t,主要由混匀料和冷返矿＋灰带入（合计95.40%）,由烧结矿和返矿带出（合计97.77%）;1#高炉的锌金属带入量为0.85kg/t,主要由烧结矿和球团矿带入（合计92.45%）,由重力灰和布袋灰排出（合计82.86%）。结合莱钢生产实际,提出了降低锌带入量及提高脱锌率的建议,如除尘灰、污泥等通过转底炉脱锌后再利用,通过高炉操作降锌等。