烧结熔剂活性度及高温液相行为研究

使用指示剂滴定法和"座滴法"研究了烧结熔剂(生石灰、白云石)活性度及高温液相行为。结果表明:生石灰的活性度存在显著差异,生石灰活性度主要取决于"匀速滴定阶段"的活性度;活性度较高的生石灰与Fe_2O_3纯试剂反应的特征温度较低、特征温度区间较窄;石灰石与Fe_2O_3纯试剂反应的特征温度较生石灰低,这主要是由于高温下生成的CaO活性度更高;白云石与Fe_2O_3纯试剂反应的特征温度最高,这主要是由于MgO·Fe_2O_3阻碍了铁酸钙的形成;白云石与Fe_2O_3纯试剂反应后的试样出现了明显的分层现象,内层矿相以MgO形成的高熔点物质为主,外层矿相以低熔点铁酸盐为主。     

全封闭皮带定量给料机在烧结熔剂配料中的应用

<正>1前言生石灰、轻烧白云石作为烧结生产的重要熔剂,其消化放热可有效提高混合料温,改善烧结过程透气性,消化生成的消生石灰胶体黏结性好,有利于混合制粒,改善混合料粒度组成及热稳定性,为厚料层烧结创造条件。进而Fe_2O_3易与CaO反应生产强度、冶金性能优异的铁酸钙,同时轻烧白云石还可加入MgO改善高     

烧结熔剂活性度对烧结矿指标影响研究

正1前言目前,烧结所使用的熔剂有钙质熔剂与镁质熔剂两种,钙质熔剂主要有石灰石、生石灰、消石灰,镁质熔剂主要有白云石、轻烧白云石等。生石灰在改善烧结矿指标过程中,通过矿化反应,促进铁酸钙形成,生产出强度高、还原性好、粒度组成理想的烧结矿,其作用已经被得到广泛认可。而石灰石作为早期烧结配加的主要熔剂逐渐被淘汰。石灰石与生石灰     

基于综合效果优化的高活性熔剂减量化烧结试验

高炉碱性熔剂在烧结中加入,对于降低烧结熔点,生成多元低熔点共晶化合物,增加液相量起主导作用的是CaO,是CaO的主要价值所在。石灰石、消石灰、生石灰、活性石灰,有的还使用白云石、高镁灰等,其价格悬殊,但作为熔剂降低烧结熔点的作用是相同的,优化熔剂结构与比例成为降低熔剂成本的有效途径之一。基于此目的,在实验室与烧结机上进行了熔剂结构优化的系统试验。实验室试验表明,具有高活性度的生石灰或活性灰比例并不是越高越好,对于不同的物料结构,有一适宜生石灰/活性灰比例使烧结综合效果达到最好。与基准"石灰石4. 3%+生石灰a%+活性灰b%"进行综合评价,综合效果最好的是"石灰石6. 2%+生石灰a%+活性灰(b-1)%",其次是"石灰石5. 3%+生石灰a%+活性灰(b-0. 5)%",第三是"石灰石5. 2%+生石灰(a-0. 5)%+活性灰b%"。工业验证试验表明生石灰/活性灰下调后用石灰石替代,烧结矿产质量能耗指标不仅没有受到影响,反而还有改进。1台360 m~2烧结机试验中,活性灰下调0. 5%,台时产量上升18. 16 t/h,固体燃耗下降1. 27 kg/t,转鼓指数上升0. 18%,自产返矿率下降2. 23%。另一台260 m~2烧结机试验,生石灰下调0. 75%,台时产量上升9. 37 t/h,固体燃耗下降2. 01 kg/t,转鼓指数上升0. 15%,自返率下降1. 26%。高价熔剂生石灰/活性灰减量烧结技术应用取得显著效果。     

烧结熔剂高温性能的研究

为了解熔剂高温分解特性和高温反应特性在烧结工艺中的重要作用,通过熔剂高温分解特性试验,得到白云石和石灰石的分解温度,发现白云石失重率较高,产生气孔较多,有利于提高烧结料层透气性。烧结前对白云石和石灰石进行轻烧水化,有利于提高烧结矿质量;通过熔剂高温反应特性试验,发现石灰石和生石灰的变形温度和半球温度相差不大,白云石的变形温度和半球温度较高,且温度区间较大,石灰石和生石灰的流动性优于白云石。     

电炉冶炼高碳锰铁使用生石灰的解析

通过对目前电炉冶炼高碳锰铁时加入不同熔剂的方法,分析了使用石灰石或生石灰冶炼时的耗热情况,并折算成耗电指标。用实例说明了使用生石灰辅之以白云石或高 MgO 烧结矿的冶炼效果。     

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。     

精矿粉对烧结矿液相行为和结构的影响

粒级细小的精矿粉在烧结过程中对粘结液相的形成和行为具有重要影响。采用相图软件(FactSage~(T M)7.0)对Fe_2O_3-CaO-SiO_2渣系进行了计算,通过烧结试验对铁矿粉烧结液相行为受脉石的作用进行了研究。结果表明,SiO_2能明显提高烧结液相的量和流动行为,Al_2O_3也有一定的促进作用,MgO则会轻微抑制;同化性能好的铁矿粉形成的初始液相层较薄,有利于其扩散;烧结矿的粘结相和孔洞结构主要受液相行为和大颗粒矿粉自身致密度影响。     

Al_2O_3、MgO交互作用对复合铁酸钙生成影响机理

为了探索复合铁酸钙的生成机制以优化烧结工艺,提高烧结矿质量,采用相平衡法研究了准化学平衡条件下Al_2O_3与MgO在烧结中的行为。结果表明,Al_2O_3和MgO的共同存在有利于复合铁酸钙(silico-ferrite of calcium and alminum,简称SFCA)的生成,但存在着交互作用,MgO促进赤铁矿分解生成磁铁矿,Al_2O_3的存在可抑制MgO的作用,减少磁铁矿生成,尤其在Al_2O_3质量分数较高时,MgO促进磁铁矿生成能力降低,促进SFCA生成作用增强。当MgO质量分数为2%时,添加质量分数2%的Al_2O_3矿相中磁铁矿质量分数快速降低,SFCA质量分数快速增加;随着Al_2O_3质量分数升高,SFCA晶面间距减小,晶体结构稳定性增强,有利于SFCA的生成;Al_2O_3质量分数超过3%后,孔洞结构增多,SFCA质量分数增加变缓,磁铁矿质量分数呈降低趋势,赤铁矿质量分数有升高趋势。     

原料结构对高MgO烧结矿生产的影响

原料结构的优劣对烧结生产技术质量指标具有决定性的影响,尤其是在低硅烧结条件下生产高MgO烧结矿.本文介绍了以白云石、高镁粉作MgO熔剂添加剂生产高MgO烧结矿时,原料结构对烧结生产影响的试验研究情况.研究结果表明,只要原料结构选择适宜,无论使用何种MgO熔剂添加剂,均可在低硅条件下生产出具有高强度的高MgO烧结矿.     

Influence of limestone particle size on iron ore sinter properties and productivity

Iron ore fluxed sinter is the main ferrous burden of Jindal south west steel limited (JSWSL) blast furnaces. In sinter plant fluxes including limestone and dolomite are added to improve the sinter properties of iron ore and to provide an appropriate slag composition of the blast furnace. The raw material grain size affects the sinter process considerably because the sinter productivity and quality are strongly dependent on the green permeability of the bed, which is determined by the particle size distribution of the raw materials, the granulation effectiveness and by the sintering process itself. It is well‐known that in fluxed sinter, the size of limestone affects productivity and physical and metallurgical properties of the sinter. It is therefore necessary to understand the role of limestone particle size on sinter properties and productivity. In the present work laboratory sintering experiments have been carried out with different levels of limestone mean particle size (from 0.14 to 1.83mm) to understand the influence of limestone particle size on mineralogy, productivity, physical and metallurgical properties of the sinter. Sinter productivity increased with increasing limestone mean particle size due to improved sinter bed permeability. Sinter with limestone mean particle size of 1.25 to 1.52 mm yielded better sinter strength and lower RDI compared to sinter with smaller or larger limestone mean particle size. Higher sinter strength is due to better and uniform distribution of limestone particles, and better bed permeability enabled easy assimilation and effective distribution of calcium ferrite phases. The improvement in sinter RDI is due to change in mineralogy of the sinter compared to coarser and finer limestone mean particle size.     

The effect of dolomite addition on the properties of sinters produced from a high aluminous iron ore

This study provides a systematic approach to an evaluation of the sinter properties with increased MgO addition for superfluxed sinters produced from a high aluminous ore. The investigation revealed that part or full replacement of limestone by dolomite in the sinter mix leads to a drop in sinter cold strength, reducibility and production rate, but has a favourable influence on low-temperature reduction strength and probably better softening and meltdown properties. The change in sinter mineralogy due to the MgO addition has a paramount influence on the sinter properties. The Gua iron ore having a high alumina content, is easily amenable to sintering and the sinters produced can constitute a good burden material because of their high reducibility, good cold and hot-strength characteristics. Improved production rates can be expected by choosing dolomites having a smaller crystal size or choosing other suitable MgO-bearing materials. A high circulating load should be expected while producing MgO-bearing sinters.     

Influence of magnesia on iron ore sinter properties and productivity

Abstract

Dolomite and other MgO bearing materials are being increasingly used as basic flux constituents for production of fluxed sinters. Addition of flux materials in sinter influences the resultant sinter microstructure and chemical properties. The physical and metallurgical properties of sinter mainly depend on mineralogy of the sinter. Dolomite is the source of double carbonate of calcium and magnesium. Recent studies reveal that, apart from the additional fuel needed, the addition of dolomite and MgO bearing material greatly influences the magnetite content and the properties of the sinter produced. The increasing use of MgO bearing fluxes in the blast furnace burden, and the trend to incorporate a major part of fluxes in the sinter mix led to an investigation of the influence of MgO on sinter properties and productivity. In this study, the systematic investigation has been made on the influence of MgO% (1·4 to 2·6) on sinter mineralogy and sinter properties with dolomite. Microstructural examination of dolomite sinter revealed that hematite and calcium ferrite phases decreased whereas magnetite phase increased with increase in MgO percentage in sinter. From the laboratory pot grate sintering results it was found that sinter reduction degradation index improved whereas tumbler index and reducibility decreased with increase in MgO%.     

钢渣替代烧结白灰的试验

钢渣中含有大量能够循环利用的钙、铁、镁等成分,替代熔剂用于烧结过程是钢渣循环利用的重要途径之一。为提高钢渣在烧结过程中的使用比例,回收利用钢渣中的有用成分,采用XRD、矿相显微镜、微型烧结装置和烧结杯装置对某钢厂转炉钢渣进行了替代烧结白灰的试验研究。结果表明,钢渣的矿物组成主要是RO相(MgO、FeO和MnO的固溶体)、硅酸二钙、硅酸三钙等;钢渣作为熔剂用于烧结能够促进液相生成,提高液相流动性;钢渣搭配优质白灰替代部分低质白灰能够提高烧结矿的成品率和平均粒径,降低固体燃耗。     

Influence of Magnesia on Iron Ore Sinter Properties and Productivity – Use of Dolomite and Dunite

For production of fluxed sinter the use of dolomite and other MgO bearing materials has increased in the recent past. Flux materials influence the microstructure and chemical properties of the resultant sinter. Improvement in raw material quality and use of alternative raw materials play an important role for improving the sinter quality and overall economics of iron and steel making. The physical and metallurgical properties of sinter mainly depend on the mineralogy of the sinter. Dolomite is composed of calcium magnesium carbonate and dunite consists of magnesium silicate. In the present work laboratory sintering experiments have been carried out with different MgO level (1.40 to 2.60 mass%) to know the influence of MgO on the mineralogy, productivity, physical and metallurgical properties of sinter prepared by using dolomite and dunite. Microstructural examinations of the produced sinter revealed that dunite sinter is bounded with higher amounts of hematite and less calcium ferrites when compared to dolomite sinter. Hematite and calcium ferrite phases decreased whereas magnetite phase increased with increase of magnetite content in sinter using both dolomite and dunite. From the test results it was found that dunite sinter showed better metallurgical properties whereas dolomite sinter showed better physical properties.     

配用WPF粉矿烧结试验研究

通过小型烧结试验装置对低品质WPF澳矿粉的高温特性进行了研究。在此基础上,对应用WPF的配矿方案进行了烧结杯试验。研究结果表明,WPF的同化性较高,但是液相流动性较弱,因此可以利用其高温特性与其他矿粉搭配烧结,弥补其SiO2和Al2O3含量较高的缺点。WPF矿粉配比在10%～15%时有利于烧结矿取得良好的冶金性能,同时增加烧结矿中还原性能良好的针状铁酸钙含量。     

w(MgO)和w(Al2O3)对混合炉料软熔性能的影响

 改善高w（Al2O3）矿石冶炼的常用方法是增加烧结矿w（MgO），则高碱度烧结矿中w（MgO）和w（Al2O3）均升高且w（MgO）/w（Al2O3）改变。为降低冶炼成本，需合理调控高炉综合炉料的w（MgO）和w（Al2O3）。以现场烧结矿和天然块矿为试验原料，考察了烧结矿中w（MgO）和w（Al2O3）均增加的条件下混合炉料软熔性能的变化规律，结合相图和X射线衍射分析w（MgO）和w（Al2O3）的影响机制。结果表明，随着烧结矿中w（MgO）和w（Al2O3）增加，混合炉料软化特征温度降低；渣相熔化温度和黏度下降引起混合炉料的熔化特征温度降低，添加MgO能改善高Al2O3炉料的软熔性能，达到适宜的 w（MgO）/w（Al2O3）即可。     

轻烧白云石对烧结矿性能的影响

 针对水钢大量轻烧白云石粉末未能有效利用的情况,进行了烧结中添加轻烧白云石的试验。研究了轻烧白云石与白云石的质量比和MgO含量这2种因素对烧结矿性能的影响。结果表明：随着轻烧白云石与白云石质量比的增加,烧结矿质量指标和低温还原粉化性能先增加后降低,轻烧白云石与白云石质量比为0.67时,烧结矿转鼓强度为68.26%,落下强度为73.51%,成品率为76.14%;MgO质量分数在1.9%~2.5%之间变化时,MgO含量对烧结矿质量影响不明显,MgO含量增加有利于提高烧结矿的低温还原粉化性能,但MgO含量增加将导致烧结矿TFe含量的降低,TFe质量分数从54.27%降至53.28%;综合考虑,最佳工艺条件为轻烧白云石与白云石质量比为0.67,MgO质量分数为1.9%。