高配比磁铁精矿烧结技术的研究进展

 随着传统高品位铁矿石资源的日趋枯竭,烧结用铁矿石资源已经从赤铁矿类型逐渐转变为复杂综合的铁矿类型。但某些铁矿石的杂质和烧损较高,细粒级比例较多,严重影响了烧结性能和烧结矿质量,如烧结矿品位、强度和固体燃耗等。磁铁精矿具有含铁品位高、杂质低的特点,而且在氧化时能够释放出大量的热量。配加磁铁精矿不仅可以改善烧结矿质量,而且还具有减少烧结燃料消耗的潜力。然而,大多数磁铁精矿是经过处理后的铁矿粉,其粒度非常细,会对烧结料层透气性产生很大的负面影响,从而影响烧结过程,不利于烧结生产率的提高。在调查了磁铁精矿烧结特性的基础上,回顾和评论了高配比磁铁精矿烧结技术的最新进展,包括添加剂技术、原料预处理技术、预造块技术、复合烧结技术、气体燃料喷吹技术、双层预烧结技术等。通过分析烧结料层的透气性和控制烧结过程中的化学反应,论证这些新技术在高配比磁铁精矿烧结中的潜力,期望充分发挥磁铁精矿的优点,改善100%磁铁精矿或高配比磁铁精矿烧结混合料的烧结性能,为高生产效率条件下生产出优质低耗的烧结矿提供理论依据和技术方案。     

全精矿低温烧结最佳工艺制度的研究

本文主要介绍三个烧结工艺参数──料层高度、燃料配比、烧结负压对烧结生产率、烧结矿质量、燃料消耗影响的试验研究结果。结果表明：全磁精矿低温烧结可以获得高产、优质、低耗的技术经济指标；低碳高料层操作是实现低温烧结的必要手段；烧结矿中ＰｅＯ含量对其还原性的不利影响较小．并得到了最佳烧结工艺参数。     

钒钛磁铁精矿预制粒烧结研究

本文通过在采取不同精矿比例与不同生石灰比例参与预制粒进行烧结试验研究,探索了强化钒钛磁铁矿烧结的新途径。结果表明：在钒钛磁铁精矿烧结中,精矿参与预制粒比例增加,烧结速度提高;生石灰比例增加,烧结矿强度指标改善,利用系数提高。结合攀钢的生产实际,采取预制粒精矿在25%~50%、生石在4%等措施,可以起到强化烧结的作用。     

高比例褐铁矿与细磁精矿粉配矿技术研究

在对褐铁矿-扬迪矿的性能进行了理、化、热力学性能分析研究的基础上,与太钢自产超细磁铁精矿粉尖山粉进行了合理配矿,经过大量的烧结杯试验和烧结矿冶金性能检测,优化出了适宜的配比方案,开发出了超细磁铁精矿粉与高比例褐铁矿配矿烧结技术,应用于生产实践,并实施了有利措施,烧结料层透气性得到了改善,烧结矿产质量指标保持在较好水平,配矿成本大大降低,取得了很好的应用效果。     

典型钒钛磁铁矿的烧结基础特性

 近年来,钒、钛和铬等重要金属的价格飞涨,钒钛磁铁矿资源的高效开发利用,不仅能缓解铁矿石资源的短缺问题,还能很好地解决重要金属的供需矛盾,有利于中国钢铁工业的可持续发展。通过微型烧结设备对国内使用量较大的5种典型钒钛磁铁矿的烧结基础特性进行了系统研究,同时使用XRD和SEM-EDS对精矿粉的物相组成进行了分析。研究表明,钒钛磁铁矿的基础特性与其化学成分和物相组成的联系紧密,低钛型钒钛磁铁矿的主要物相为磁铁矿,烧结基础特性的综合评价指数相对较好,其中CJ矿的最好,而高钛型钒钛磁铁矿的主要物相为磁铁矿和钛铁矿,它们的烧结基础特性均很差。总体来说,钒钛磁铁矿的烧结基础特性普遍较差,在使用过程中应尽可能与烧结基础特性较好的铁精矿搭配。     

高钒钛磁铁精矿配比烧结强化的研究

在烧结配加较高配比的攀精矿时,烧结矿产量、质量下降,为研究强化烧结的措施,采用烧结杯开展了试验研究。通过优化原料结构、强化制粒、强化低温成矿等试验,得出攀精矿配比55%~58%时切实可行的强化技术措施:1)添加1.2%左右的生物质B或1.6%左右的生物质D;2)添加0.2%左右的复合粘结剂B或1.0%左右的复合粘结剂LF;3)添加1.5%左右的液态粘结剂1号;4)用FMG替代澳矿。综合比较,在攀精矿配比55%~58%的条件下,采取添加1.0%左右的复合粘结剂LF或1.6%生物质燃料D进行强化烧结,可以稳定提高烧结矿产量、质量。     

Al_2O_3/SiO_2对低温烧结成矿规律的影响

研究了混合料 Al2 O3/Si O2 对低温烧结时烧结矿成矿规律的影响 ,揭示了低温烧结时铁酸盐的矿物含量、化学成分、结晶状态、成矿特性等的内在变化规律 ,指出调整混合料 Al2 O3/Si O2 是钒钛磁铁精矿实现低温烧结的前提条件     

LEACHING RATES OF ICEL-YAVCA DOLOMITE IN HYDROCHLORIC ACID SOLUTION

Additives can give rise to obvious, step-wise changes both in the oxidation process and in the sintering process. Therefore, the oxidation and sintering characteristics measured in dried pellets prepared from pure magnetite concentrates can not be representative for those characteristics in dried pellets containing additives. The oxidation and sintering characteristics of magnetite iron ore pellets balled with a novel complex binder (namely MHA) were mainly investigated by batch isothermal oxidation measurements in this research. Combined results reveal that the thermal decomposition of MHA binder influences the oxidation and sintering processes of dried pellets. Oxidation rate of pellets increases obviously with increasing the oxidation temperature in the range from 800°C to 1000°C. And the remaining FeO content declines gradually when separately heated for 10 min at low temperature (<1000°C). However, the oxidation rate of pellets decreases distinctly when oxidation temperature is higher than 1000°C. In addition, when oxidation temperature increases from 1000°C to 1250°C, the FeO content of pellets goes up obviously, particularly at 1250°C. The FeO content in the core of sintered pellets heated at 1250°C can even reach 29.68%. SEM spectrum analysis demonstrate that some iron appears in forms of wustite in sintered pellets, which indicates that the reduction reaction of iron oxide occurs during the high temperature sintering process. This is explained by the occurrence of reducing atmospheres because of the pyrogenic decomposition of MHA binder.     

磁铁矿在不同气氛下的烧结行为

采用－红外加热炉在模拟烧结温度制度的条件下，研究了磁铁矿在工业氮气及氧化气氛中的烧结行为。结果表明，在工业氮气中铁酸钙可以由磁铁矿直接生成。以该方式从烧结混合料中形成的铁酸钙含量甚微，所形成的烧结矿则由磁铁矿和硅酸盐组成。氧化气氛下烧结使赤铁矿和铁酸钙成为烧结矿的主要矿物。故磁铁矿烧结的关键在于将磁铁矿氧化，改变成矿过程而生成良好结构的烧结矿。在磁铁矿氧化不能充分发展时，配加赤铁矿是改善磁铁矿烧结     

攀钢高品位精矿烧结试验研究及生产实践

针对攀钢钒钛磁铁精矿品位提高的情况,在实验室进行了高品位攀精矿烧结试验研究。结果表明,高品位攀精矿烧结性能较差,对烧结矿转鼓强度、成品率及冶金性能有不利影响。采用适当提高混合料水分和配碳量,提高料层高度、提高碱度、返矿预润湿等技术措施,均可以有效地强化高品位攀精矿烧结过程,改善烧结矿的矿物组成和结构,从而提高烧结矿的转鼓强度和成品率,改善其冶金性能。用高品位攀精矿替代部分进口矿烧结是可行的。生产上采用后取得了良好的效果。     

Thermodynamic study of evolution of sinter phases at different alumina level

Though sintering is controlled by kinetics of various reactions and is far from equilibrium, a thermodynamic analysis can provide useful inputs on melt formation and helps understand deviation from actual process conditions. The thermodynamic software ‘FACTSAGE?’ was used for this study. The general sequence of reactions during the heating cycle is as follows: decomposition of calcium carbonate to calcined lime; formation of calcium ferrites/silicates; decomposition of calcium ferrites, reduction of haematite to magnetite and formation of spinel and silicates; assimilation of ferrites, silicates, spinel and magnetite into the melt. During the cooling stage, the amount of melt decreased with subsequent precipitation of phases such as magnetite, ferrites, silicates, spinel and formation of haematite. It is very much clear that the sinter made by using higher alumina levels generate fewer amounts of oxides and more slag phase compared to its low alumina counterpart.     

Oxidation and Induration Characteristics of Pellets Made from Western Australian Ultrafine Magnetite Concentrates and Its Utilization Strategy

Western Australian magnetite concentrates normally have ultrafine granularity and much higher specific surface areas than Chinese magnetite concentrates owing to the significant pre-grinding and beneficiation for saleable iron grade.Such characteristics will inevitably affect the subsequent pelletization process.However,very few investigations have been done before.Thus,the oxidation and induration characteristics of pellet made from a Western Australian ultrafine magnetite concentrate were revealed by conducting routine preheating-roasting tests in an electric tube furnace and investigating the microstructure of fired pellets under an optical microscope in comparison with that of pellets made from typical Chinese magnetite concentrate.The liquidus regions of CaO-SiO_2-Fe_2O_3 and CaOSiO_2-Al_2O_3 ternary systems in air at various temperatures were calculated by FactSage software to explain the importance of liquid phase in the consolidation of fired pellets.The results show that pellet made from ultrafine magnetite concentrate possesses better oxidability and preheating performance than that made from Chinese magnetite concentrate.However,it has inferior roasting performance,usually requiring conditions of roasting at 1 280℃ for at least 30 min to acquire sufficiently high compressive strength,which are attributed to higher temperature sensitivity caused by its smaller particle size and less formation of liquid phase because of low impurities like CaO and Al_2O_3 in raw materials.Correspondingly,its roasting performance can be significantly improved by blending with Chinese magnetite concentrates or increasing the pellet basicity(wCaO/wSiO_2).By comprehensive evaluation,blending with Chinese iron ore concentrates is an appropriate way to utilize Western Australia ultrafine magnetite concentrates.     

反射炉炼铜渣综合利用技术研究

在铜熔炼反射炉渣中铜铁赋存状态分析基础上,采用火法贫化和磁选技术对炉渣进行综合利用探索。此反射炉渣含1.06%Cu和36.41%Fe,其中32.5%的Fe以Fe3O4形式存在,53.5%的Fe以2FeO.S iO2形式存在,铜、铁、硅矿物紧密共生,相互交织。研究结果表明,转炉渣返回贫化作业会导致反射炉渣含铜较高,添加一定量黄铁矿精矿,采用火法贫化工艺能有效降低渣含铜。将贫化后铜渣脱硅缓冷、磁选,所得铁精矿品位62%,回收率达70.2%,实现了反射炉熔炼渣的综合利用,可用作炼铁原料。     

高品位攀精矿烧结试验研究

针对攀钢钒钛磁铁精矿品位提高的情况，在实验室进行了高品位攀精矿烧结试验研究。结果表明，高品位攀精矿烧结性能较差，对烧结矿转鼓强度、成品率及冶金性能有不利影响。采用适当提高混合料水分和配碳量，提高料层高度、提高碱度、铁精矿预先制粒、返矿预润湿等技术措施，均可以有效地强化高攀精烧结过程，改善高攀精烧结矿的矿物组成和结构，从而提高烧结矿的转鼓强度和成品率，改善其冶金性能。采用高品位攀精矿替代进口矿烧结是可行的。     

达钢烧结配矿试验研究

根据达钢烧结生产实际情况,研究了钒钛铁精矿配比对烧结过程和烧结矿冶金性能的影响。结果表明：在烧结杯实验条件下,随着钒钛铁精矿配比增加（达到12%）,垂直烧结速度会下降（低于25mm/min）,低温还原粉化指标也会变差。综合考虑,钒钛铁精粉比例目前控制在5%左右为宜。     

浮选赤铁精矿烧结节能降耗的实践

赤铁矿烧结主要是还原再氧化反应过程，与磁铁矿烧结相比，其能源消耗较高。用浮选法选别后的赤铁精矿具有细、粘等特点，烧结过程中表现为混匀难、造球难、烧结难、能耗高。本文介绍了鞍钢矿业集团东烧厂采用这种浮选赤铁细精矿烧结的节能降耗经验和措施。     

承钢高碱度钒钛磁铁矿烧结性能研究

承钢钒钛磁铁矿烧结面临的两大问题是机械强度差、低温还原粉化严重。从烧结过程、矿物组成、矿物结构、烧结矿强度和低温还原粉化几个方面对承钢高碱度烧结进行研究,得出碱度在2.0~2.3时转鼓强度与低温还原粉化率出现了低洼区现象,生产要避免此区间。     

配加高比例超细精矿粉对烧结的影响

为了充分利用自产资源,进行了高比例超细精矿粉对烧结影响的试验。结果表明:随着精矿粉配比的增加,烧结矿的产量、质量指标呈下降趋势,当精粉率超过70%时,烧结负压升高,烧结速度降低,利用系数下降了8.6%,转鼓强度降低3%以上;随着精粉配比的增加,烧结时混合料所需水分增加,且适宜区间变窄,水分的控制难度增大;特别是全精粉烧结时,适宜水分质量分数的波动范围只有±0.25%,当水分控制不稳定时出现熄火、烧结过程停滞的现象。     

碱度对钒钛烧结矿强度和烧结过程的影响

在新的配矿条件下，研究了碱度对承钢钒钛磁铁烧结矿的强度、矿物结构和烧结过程的影响。结果表明：在大量使用澳矿时，综合考虑烧结矿碱度对承钢烧结过程、高炉炉料结构和高炉冶炼过程的影响，烧结矿碱度控制在1．9左右比较适宜。     

东烧小球团烧结制粒研究

针对东烧以利用自产浮选精矿为离,进行生产酸性小球团热烧结矿的改造,进行了小球团烧结工艺的制粒研究。在采用新设备进行制粒基础上,提出了保证制粒效果的技术措施及制粒三大要素,即混合料要充分润湿;严格控制水分;制粒机速度必须可调。同时,指出了小球力烧结是普通烧结技术改造的良好途径,可独得明显的效益。