微波场中含碳铬铁矿粉反应过程升温特性数值模拟

 对含碳铬铁矿粉在微波场中的升温特性作了分析。首先是分析加热谐振腔体的几何结构、耦合方式及物料的位置等来推测微波场分布，并通过实验进行了验证；进而分析了冶金化学反应的详细过程，结合含碳铬铁矿粉在微波场中的相关热及物理性质的变化，得出了在这个反应过程中物料的等效损耗因子；最后通过微波耗散功率与物料温度的关系的模拟计算，拟合出含碳铬铁矿粉的升温曲线。这种方法对于分析不同物料、不同配比、不同体积条件下在类似场结构下的微波冶金物料的化学反应过程中升温特性也是有效的。     

微波场中含碳铬矿粉升温特性曲线数值模拟

在微波加热过程中,冶金物料在微波照射下的温度分布是它与微波场相互作用且吸收微波的过程, 此期间伴随的传输过程所导致的升温都归因于微波能耗散转化为热能。分析了微波场影响含碳铬铁矿粉升温特性一系列重要因素,即分析了影响微波场分布的加热谐振腔体的结构和多管耦合方式;结合含碳铬矿粉在微波场中的比热容、介电性质等热及物理性质的变化,通过计算模拟得出微波耗散功率与温度的关系,进而拟合出含碳铬矿粉的升温曲线。这种方法对于不同物料、不同配比、不同体积条件下在类似场结构下的微波冶金物料的升温特性也是有效的     

微波加热含碳氧化锰矿粉体还原过程中锰铁金属化物的渗碳行为

纯净锰铁对纯净钢质量的影响至关重要,尤其是碳含量。微波可以快速加热含碳氧化锰矿粉进行体还原,为获得低碳锰铁奠定了基础。在碳氧原子摩尔比为1．06,rCaO：rSiO2分子摩尔比为1．28的条件下,采用微波加热法,对含碳氧化锰矿粉加热到一定温度并保温一定时间。结果表明：还原物料中锰铁金属化物的碳含量在0．11％～0．23％之间。随着物料温度的提高和保温时间的增加,锰铁金属化物中的碳含量随铁含量增加而提高,而随锰含量的增加而降低,但锰含量与铁含量呈负相关关系。由于铁比锰易于渗碳,因此物料温度、保温时间和物料的锰铁比是影响锰铁金属化物渗碳的主要因素。     

高碳锰铁粉与高碳铬铁粉微波升温特性对比

通过对比微波场中高碳锰铁粉和高碳铬铁粉的升温特性,分析了影响物料升温特性的因素。结果表明,微波场中高碳锰铁粉的升温效果优于高碳铬铁粉,高碳锰铁粉与高碳铬铁粉在微波场中的升温曲线均可分为2个阶段,高碳锰铁粉的平均升温速率为70.9和12.4℃·min-1,而高碳铬铁粉的平均升温速率为20.0和8.33℃·min-1;2.450GHz时,高碳铬铁粉的介电损耗较大,而高碳锰铁粉的磁损耗较大;反射损耗计算表明,高碳锰铁粉有较高的微波吸收率。     

Kinetics of Voluminal Reduction of Chromium Ore Fines Containing Coal by Microwave Heating

The kinetics of voluminal reduction of chromium ore fines containing coal （COFCC） by microwave heating was studied. When the molar ratio of carbon to oxygen was 0.84 and that of CaO to SiO2 was 0.39 in COFCC, the temperature rising rate of COFCC by microwave heating was 62.5 ℃/min, 68.75 ℃/min, 70. 59 ℃/min, and 72.22 ℃/min at 1 000 ℃, 1 100 ℃, 1 200 ℃, and 1 300 ℃, respectively. The results show that the voluminal re duction of COFCC by microwave heating at solid-solid phase is first order reaction, with the apparent activation energy of 51. 480 kJ/mol. The limiting step of reaction rate for the overall reaction is the mass transfer of CO in the reduced product layer between dielectric particles of chromium ore and coal.     

Microstructure of Solid Phase Reduction on Manganese Oxide Ore Fines Containing Coal by Microwave Heating

Microstructure of solid phase reduction on manganese oxide ore fines containing coal (MOOFCC) is one of important kinetics conditions of influencing microwave heating. On condition that an atomic molar ratio of rO∶rC in MOOFCC is 1∶1.06 as well as a molecular molar ratio of rSiO2∶rCaO is 1∶1.28,1 kg of MOOFCC is heated by microwave to reach 1000-1300℃ and hold different time respectively. Experiments show that the metal phase takes the iron-based metal compounds containing manganese as the main content. The manganese content of metal phase increases with the rise of temperature. The particle size of the metal phase is within the range from 0.01 to 0.05mm. MO2 phase in the stuff is entirely changed into MnO phase and the slag phase is mainly composed of wollastonite and manganese olivine. The stuff reduced is loose and massive as a whole and its porosity is from 30% to 45%. The low softening-melting property and the low density of the stuff impact,to some degree,the solid phase reduction of powder by microwave heating.     

Intensifying Gaseous Reduction of High Phosphorus Iron Ore Fines by Microwave Pretreatment

 Gaseous reduction kinetics of the high phosphorus iron ore fines from Hubei in China and effect of microwave pretreatment on the gaseous reduction behavior were studied. Gaseous reduction kinetics were investigated by TG (Thermogravimetric) methods using LINSEIS STA PT 1600 thermal analysis equipment. Microwave pretreatments to the ore fines with four power levels were performed using a high temperature microwave reactor. Its effect was examined by TG methods and its mechanism was analyzed by SEM (scanning electron microscope) and EDS (energy dispersive spectrometer). Gaseous reduction tests were carried out using a tubular furnace. Results of kinetic study indicate that controlling step of the gaseous reduction of the ore fines is a mixing control of gas internal diffusion and interface chemical reaction when reduction fraction is less than 0. 8 and is solid state diffusion when reduction fraction is more than 0. 8. Microwave pretreatment of the ore fines could change the pore structure of the oolitic unit to generate cracks, fissures and loose zones, which promotes reduction in the early stage and delays the occurrence of sintering. Gaseous reduction tests show in the condition that the ore fines are pretreated with a microwave power of 450 W for 4 min and reduced under temperature of 1273 K, the gaseous reduction of the ore fines could be apparently intensified. Using CO or H2 as a reductant and ore fines being reduced for 1. 5 to 2 h , increase of metallization rate of the ore fines is 10% to 13%.     

微波加热含碳氧化锰矿粉体还原过程中磷的迁移行为

通过电子探针面扫描成分分析,研究了微波加热含碳锰矿粉体还原过程中磷的迁移行为。在rc：ro原子摩尔比为1．06、rcao：rsio2分子摩尔比为1．27的条件下,将含碳锰矿粉放入微波,冶金炉中进行加热还原并保温一段时间。结果表明：固相还原时,有53％～67％的磷分布于气相中,高于常规冶炼的气化脱磷率。温度高于1000℃后,部分磷以锰、铁磷化物的形式迁移进入金属化物中。随着温度的提高和保温时间的增加,锰铁金属化物中的含磷量随之增加。将微波加热温度控制在1100℃以内,并缩短保温时间,有利于获得低磷海绵锰铁。     

氢气还原1～3mm铁矿粉的动力学研究

在自制的kg级高温流化床中研究了氢气还原1～3 mm矿粉的动力学试验。随着时间的增加,气体利用率下降,表明还原前期反应速度快,后期反应慢;温度越高,气体利用率越高,但随着还原时间的增加,差距在逐步缩小;对于750℃,前20 min的气体利用率为9%,金属化率达到84%,说明氢气还原矿粉反应是非常迅速的。随着气速的增加,金属化率在增加,并且几乎成线性关系,因此使用氢气作为还原剂,可以允许更高的气速,从而提高设备的生产效率。随着料高的增加,金属化率不断下降,然而气体利用率却在不断升高。使用氢气作为还原剂,可以将还原温度降低到700～750℃,避免流化床过程中的粘结难题;试验中氢气还原1～3 mm铁矿粉时的表观活化能为58.4kJ/mol。     

电焊条用钛铁矿的介电特性及微波加热特征

电焊条用含钛原料的介电特性研究对于拓宽焊条制造原料来源和发展微波加热制备还原钛铁矿具有重要的指导意义.采用同轴探头反射法测定了钛铁矿粉末（含TiO237%～47%）在2.45 GHz频率下和20～80℃之间的介电特性,并测定钛铁矿在微波场下的温升特性.研究结果表明：钛铁矿的介电常数和介电损耗因子及损耗角正切随着温度的上升而增加,介电特性总体随着含钛品位增高逐渐增强.钛铁矿的穿透深度在40～80℃之间随温度增加逐渐降低,微波加热钛铁矿的最佳物料厚度为3～6 cm.微波场下钛铁矿的升温曲线表明温度和微波加热时间具有一个非线性关系.     

某钢厂常用4种铁矿粉烧结基础特性

以提高某钢厂烧结矿质量为目标,对烧结矿质量影响较大的铁矿粉高温特性进行了研究。利用FactSage 7.1热力学软件计算出铁矿粉在1 280 ℃、碱度为3.0时产生的液相量和液相黏度指数,并以热力学计算为基础采用TSJ-2型红外线快速高温烧结炉进行4种铁矿粉基础特性测定试验。试验结果表明,A、D 两种铁矿粉同化温度较高,同化性较差;C 种铁矿粉同化性较好,B种铁矿粉同化性最好。当试验温度为1 280 ℃、碱度为3.0时,A 和D两种铁矿粉的液相流动指数较低;C种铁矿粉的液相流动指数较好,B 种铁矿粉的液相流动指数最好。由FactSage 7.1热力学软件计算得出,A铁矿粉液相量为51.46%、黏度为0.031 Pa·s,B铁矿粉液相量为77.8%、黏度为0.032 Pa·s,C铁矿粉液相量为66.64%、黏度为0.035 Pa·s,D铁矿粉液相量为70.66%、黏度为0.044 Pa·s,根据流动性指数公式得出结果与试验结果相一致。     

微波加热含碳氧化锰矿粉固态还原过程中硫的分配

在rC∶rO原子摩尔比为1.06、rCaO∶rSi O2分子摩尔比为1.27的条件下,通过电子探针面扫描成分分析,对微波加热含碳氧化锰矿粉固态还原过程中硫的分配进行了研究。结果表明:加热温度为1 000~1 300℃时,88%~96%的硫分配于气相中,锰铁金属化物中的平均硫含量为0.002%~0.017%;随着微波加热温度的提高和保温时间的延长,锰铁金属化物中的含硫量与含铁量呈负消长的关系,而与含锰量呈正消长的关系;提高微波加热温度和延长保温时间,有利于进一步改善含碳锰矿粉的气化脱硫效果。与传统冶炼方法相比,微波加热含碳锰矿粉以气化脱硫为主,并可以获得良好的脱硫效果。     

鞍钢鲅鱼圈烧结配矿试验研究与工业应用

为保证鞍钢鲅鱼圈高炉顺利开工,根据鲅鱼圈的现有运输条件和铁粉矿资源,进行了高比例赤铁粉矿烧结的配矿研究。通过对各种配矿方案(包括全部采用赤铁粉矿)进行烧结杯试验,并对烧结矿的高温冶金性能、矿物组成和微观结构等进行检测、比对和分析,认为方案1能够满足鲅鱼圈分公司烧结开工的配矿要求。经生产验证,烧结矿合格率、品位、碱度及转鼓强度、利用系数、<5 mm粉末含量等指标维持在3σ~4σ的水平,可以满足大高炉生产需求,保证高炉的稳定顺行。鲅鱼圈烧结和高炉的开工标志着鞍山钢铁集团大比例粉矿烧结时代的开启。     

Smelting characteristics of fluxed chromite sinter and its performance assessment in electric arc furnace to produce high carbon ferrochrome

More than 80% of the high grade chromite ores are fragile and tend to form fines during their handling. In order to utilise these chromite ore fine, in ferrochrome production, agglomeration is necessary. In the present study, the direct sintering of chromite ore fines in the presence of coke breeze has been carried out, which does neither require further grinding of ore fines (???10?mm) nor binder. It uses suitable fluxes and coke breeze as heat source to raise temperature up to 1600°C and produces a semifused mass (20% molten phases) with good strength. The developed sinter showed very good strength properties suitable for cold handling. Since it contains higher amount of fluxes than conventional pellet, the study on its smelting characteristics is necessary to assess its suitability in Fe–Cr production. In the present paper, smelting reduction characteristics and assessment of its performance with respect to the lump ore in a 50?kVA electric arc furnace have been studied in 10?kg scale. Different smelting parameters such as coke and flux requirement, energy consumption, etc. has been optimised through both thermodynamically and experimentally to get maximum extent of reduction, metallic yield and chromium recovery. Coke (21%), quartzite (7.52%) and bauxite (10%) addition with 45?kWh of heat input was found to be optimum to achieve 76% metallic yield and 91%, chromium recovery. In the comparative study in identical condition, the chromite sinter showed much better metallic yield (76%) and higher chromium content (54.6%) in the produced ferrochrome than the lump ore (70 and 51. 9% respectively) of the same grade.     

微波处理低品位锰矿冶炼硅锰合金试验研究

对微波加热国产低品位锰矿含碳球团冶炼硅锰合金进行试验研究,探明了还原剂种类、配碳系数、碱度等对锰元素回收率的影响。结果表明,采用微波加热含碳低品位锰矿球团可以冶炼出硅锰合金。以木炭为还原剂时,锰回收率可达63.3%,冶炼效果明显优于兰碳。配碳系数及碱度对冶炼效果有明显影响,最佳配碳系数为1.3,最佳碱度为0.7。通过混合高品位锰矿的方式,提高混合锰矿中锰含量,对锰元素回收率没有明显影响。     

锰矿粉利用技术研究

系统地分析了当前锰矿资源及利用状况，并提出了一种利用贫锰矿粉的新工艺——微波加热含碳锰矿球团制备海绵锰（铁）。对可持续利用我国大量贫锰矿资源具有重要意义。     

济钢2#1750m3高炉大矿批冶炼实践

由于原燃料条件变差,造成高炉风量减少,透气性变差,炉缸侧壁温度升高,炉况出现波动。济钢2#1750m3高炉采用大矿批冶炼,通过优化热制度、造渣制度、装料制度、送风制度等,高炉风量由3002m3/min提升到3186m3/min,利用系数由2.234t（/m·3d）提高到2.394t（/m·3d）,炉缸侧壁温度由1023℃降至669℃,基本实现了低耗、高效冶炼的目标。     

铁矿粉反应性研究

研究了铁矿粉与氧化钙反应的熔化特性。实验结果表明，铁矿娄与氧化钙反应生成液相的熔点温度受氧化钙的配比和铁矿粉本身的特性影响。氧化钙配比越高，熔点温度越低；铁矿粉中氧化铝提高了液相生成的熔点温度，在氧化钙配比较低时，影响比较明显；当不同矿种中的氧化铝含量接近时，含结晶水的矿种与氧化钙反应生成液相的熔点温度较低；矿种相同时，粒度越细，熔化温度越低。     

难选金矿微波预处理边磨边浸非氰化试验研究

某难选金矿石化学成分分析结果显示,金品位为3.51×10-6 ,SiO2 含量高达71.88%,有害元素为碳和硫。其中,有机碳含量高达2.51%,严重阻碍了后续浸出过程的进行。XRD和金物相分析可知,矿石中主要矿物为石英、方解石及硫化矿,硫化矿以黄铁矿为主。金主要以微细粒浸染或包裹于石英、硅酸盐、硫化矿及碳酸盐矿物中。针对该难选金矿石的性质,采用非氰化药剂TL直接浸出时,浸出率较低。采用了微波预处理边磨边浸非氰化工艺,研究了微波焙烧时间、微波焙烧温度、浸出剂TL的用量、液固比及磨浸时间对金浸出率的影响。试验结果表明,在微波焙烧温度为650 ℃、微波焙烧时间为45 min的条件下,当非氰化浸出剂用量为6 kg/t、液固比为4∶1、磨浸时间为6 h时,可获得71.64%的金浸出率。     

新钢常用国内外烧结粉矿冶金价值技术经济分析

根据烧结、炼铁生产实际,采用通用铁矿粉冶金价值技术经济分析方法分析了新钢公司常用国内外烧结粉矿的生产使用效果。认为在目前价格条件下综合比较,南美粉矿的生产使用效果优于印度粉和澳粉(含杨迪粉)。采购南美粉矿在现阶段有其经济性和合理性。