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。     

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。     

微波加热内配碳酸钙高碳铬铁粉固相脱碳

高碳铬铁无渣脱碳法可避免有毒铬渣的排放,利用微波场可快速加热粉状物料的特性,在高碳铬铁粉中配加一定比例的碳酸钙粉,可实现高碳铬铁粉快速固相脱碳.实验结果表明:配加一定比例的碳酸钙粉,不会影响内配碳酸钙高碳铬铁粉混合物料的微波加热特性;提高混合物料的脱碳摩尔比、微波加热温度和保温时间,有利于高碳铬铁粉的深度脱碳,但相应加剧脱碳铬铁粉的氧化程度.合适的固相脱碳条件为:脱碳摩尔比1∶1.0~1∶1.4,微波加热温度1100℃,保温脱碳时间60 min.在上述条件下可使碳质量分数为8.16%的高碳铬铁粉脱碳至3.91%~1.71%,脱碳率为52.08%~79.04%.      

微波加热高碳铬铁粉固相脱碳动力学

采用微波加热对高碳铬铁粉固相脱碳进行了动力学研究.以碳酸钙粉为固体脱碳剂,按高碳铬铁粉中碳与碳酸钙粉完全分解后产生的CO₂的摩尔比为1︰1和1︰1.4混合,在微波场中对内配碳酸钙高碳铬铁粉加热到不同温度并保温脱碳一定时间,测定其碳含量并计算固相脱碳反应的表观活化能.实验表明:提高内配碳酸钙的比例,物料的脱碳率会相应提高,但混合物料的微波加热升温速率会变小;对于脱碳摩尔比相同的物料,随着脱碳温度的提高和保温时间的延长,物料的脱碳率随之提高.当1200℃保温脱碳60 min时,两种脱碳摩尔比下物料脱碳效果最好,脱碳率分别为65.56%和82.96%.微波场能促进高碳铬铁粉中碳的活化扩散和CO₂的吸附扩散.微波加热内配碳酸钙高碳铬铁粉固相脱碳反应近似为一级反应,脱碳反应的表观活化能为68.43 kJ·mol-1.      

粉状含碳锰铁原料在微波场中的加热行为研究

采用微波加热方式,研究了粉状含碳锰铁原料的升温特性,结果表明,粉状单一原料中,焦炭粉和南非锰矿粉均可在频率为2.45 GHz的微波中加热,实现快速升温,石灰粉几乎不吸波,属于微波透明体;矿物的升温速率与其矿物成分有一定的关系,矿物成分越复杂,一般越容易吸收微波,有利于提高升温速率。混合物料的升温速率与原料粒度、配碳比、碱度有一定的关系:在原料一定时,适当提高原料的配碳比,降低碱度均有利于提高物料的升温速率;微波加热前期,原料粒度越小,升温速率越快,在加热后期,粒度越大,升温速率越快。     

微波加热含碳锰矿球团冶炼高碳锰铁的研究

对微波加热含碳锰矿球团冶炼高碳锰铁进行了试验研究,探明配碳系数、炉渣碱度对锰回收率的影响。结果表明,采用微波加热含碳锰矿料球,可以冶炼出符合要求的高碳锰铁合金。配碳系数及炉渣二元碱度对锰元素回收率影响显著,当配碳系数为1.4、炉渣二元碱度为2.0时,锰元素回收率最高可达90%以上。当配碳过量时,锰元素回收率下降明显。     

微波焙烧对高磷铁矿气化脱磷的影响

为实现高磷铁矿粉在焙烧过程中气化脱磷,促进高磷铁矿的开发利用。试验基于微波加热的方式和加入复合脱磷剂条件下,研究了微波焙烧工艺参数(温度、煤粉粒度、升温速率、保温时间)对气化脱磷率的影响。结果表明,随着温度的提高、升温速率加快及煤粉粒度的加粗,气化脱磷率明显提高,而保温时间对脱磷率的影响呈现先增加后降低的趋势,通过优化焙烧工艺参数后,高磷铁矿粉的气化脱磷率达到最大值为25.71%。     

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。     

高硫铝土矿微波脱硫溶出试验研究

采用微波焙烧脱硫工艺研究了微波加热温度、微波加热时间和矿物粒度对高硫铝土矿中硫含量的影响及氧化铝溶出率的影响;并且依据原矿和微波处理后铝土矿的XRD谱,探讨了高硫铝土矿的脱硫机理。结果表明:微波加热温度为650℃、微波加热时间为5 min、矿物粒度为0.095~0.076 mm时,高硫铝土矿的硫含量可以从4.15%降低到0.37%;在试验条件下,可以使氧化铝的溶出率从80.4%提高到98.7%。     

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     

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.     

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.     

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。     

硅锰合金粉料添加富锰矿粉冷固结压块试验研究

针对硅锰合金粉料添加富锰矿粉不易成型和成品块强度低等问题,采用新型添加剂进行压块研究,确定了最佳的添加剂配比.讨论了添加富锰矿粉在冶炼过程中能起护炉和脱硫、磷作用以及易合金化的机理.指出这是在低成本条件下合理利用硅锰合金粉料、富锰矿粉及其它类似二次资源的1个较好途径.     

微波加热与常规加热硅锰粉固相脱硅动力学比较

采用微波加热和常规加热对硅锰粉和巴西粉锰的脱硅反应进行了动力学行为研究,以巴西粉锰为脱硅剂,与硅锰粉中的硅发生氧化还原反应.微波加热和常规加热分别加热到不同温度并保温一定时间,测定产物中硅含量并计算固相脱硅反应的表观活化能.实验表明:单一和混合料均可在微波场中快速升温.随着温度的升高和保温时间的延长,两种加热方式脱硅率均随之提高,在相同实验条件下,微波加热的脱硅率和反应速率均高于常规加热,微波加热可以提高固相脱硅率;微波加热固相脱硅反应的限制性环节为扩散环节,其表观活化能为102.93 kJ·mol-1,常规加热脱硅反应的表观活化能为180 kJ·mol-1,说明微波加热能改善固相脱硅的动力学条件,提高固相脱硅反应速率,降低脱硅反应的活化能.      

Direct Reduction of Mixtures of Manganese Ore and Iron Ore

This paper presents recent results of direct reduction investigation of different combination of blends of manganese ore, iron ore and coal at the Department of Ferrous Metallurgy (IEHK) of RWTH Aachen University. A mixture of iron and manganese ore in a ratio of 75/25 is a good raw material for steelmaking of high Mn‐alloyed grades. The experimental studies consisting of reduction of (a) fine material and (b) agglomerated material (briquettes) were carried out in the range of 1273 to 1673 K. The behaviour of combined reduction of manganese ore and iron ore and the employment in the direct reduction on a coal and gas basis for production of steels with high Mn content were investigated. It was found that a high metallization degree for Mn can be reached at 1273 K with the reduction of manganese ore by hydrogen‐containing gas. Addition of carbon monoxide to the reducing gas retarded the reduction process. The addition of coal to manganese ore and iron ore blends increased the degree of reduction. The results of carbothermic reduction of briquettes consisting of a mixture of manganese ore and iron ore combined with coal as reducing agent show that a high temperature, a low Mn/Fe ratio and a high Fe₂O₃ content have a favourable effect on the degree of reduction. In order to obtain a high degree of metallization, the temperature should be higher than 1473 K. The reduction of briquettes at higher temperatures (up 1573 K) has shown a molten phase and the separation of slag and metal.     

Reuse of furnace fines of ferro alloy in the electrolytic manganese production

The use of ferro-alloy fines, especially the (Fe–Mn) alloy, to replace Rhodocrosite in the production of electrolytic manganese was studied. This approach helped to solve the environmental problem of the disposal of furnace fines and showed further advantages: the concentrations of some undesirable impurities such as Ni, Cu and Mo are smaller in the fines than in the Rhodocrosite ore; the K and Na contents are significantly higher in the fines than they are in the ore, but these elements do not affect the manganese electrodeposition; the presence of Pb in the fines is beneficial to the manganese deposition, improving the current efficiency. No size reduction is needed, in contrast with several stages of ore size reduction. The manganese content of the fines dissolves readily at room temperature. On the other hand, the ore contains manganese as carbonate requiring heating in order to dissolve in sulfuric acid solution. Fines do not generate CO₂, which is formed by the reaction of carbonate present in the ore.