西澳超细粒磁铁精矿特性及其对球团焙烧性能的影响

本文采用圆盘造球机及DSC、TG分析手段对西澳超细粒磁铁精矿和国产磁铁精矿动态成球性及氧化特性进行了研究,并对西澳超细粒磁铁精矿及配加国产磁铁精矿的球团焙烧特性进行了研究。结果表明,单一西澳超细磁铁精矿比表面积高、氧化放热反应温度低,球团焙烧时易形成双层结构,导致球团焙烧性能较差。当配加40%国产磁铁精矿时,球团适宜预热温度由1 050℃降低到950℃,适宜的焙烧温度由1 300℃降低到1 250℃,焙烧时间由40min缩短到15min;而且焙烧球团矿的抗压强度由2 313 N/个提高到2 746 N/个。焙烧球团矿的矿相研究表明:配加国产磁铁精矿后,焙烧球团矿微观结构得到明显改善,赤铁矿再结晶良好。优化配矿是改善西澳超细粒磁铁精矿球团矿焙烧特性的有效途径之一。     

蒙古高硫铁精矿生产球团矿的试验研究

通过对不同含硫量精矿的预热焙烧性能研究,提出了适宜于高硫精矿制备氧化球团矿的预热焙烧制度,可为球团矿生产使用高硫精矿提供技术指导。焙烧试验结果表明,球团工艺使用硫含量低于1.1%的混合精矿生产球团矿,适宜焙烧温度区间为1 250~1 280℃。     

优化配矿强化西澳超细粒磁铁精矿球团焙烧研究

进行了西澳超细粒磁铁精矿分别配加国产磁铁精矿和巴西赤铁精矿制备氧化球团矿的实验研究.结果表明,以100%西澳超细磁铁精矿为原料制备氧化球团矿时,球团预热及焙烧性能较差,在预热温度为1050℃、预热时间20 min及焙烧温度1300℃、焙烧时间40 min的条件下,预热球团和焙烧球团矿抗压强度分别为每个502和2313 N.西澳超细粒磁铁精矿配加40%国产磁铁精矿或20%巴西赤铁精矿时,球团适宜预热温度由1050℃分别降低到950和975℃,适宜的焙烧温度由1300℃分别降低到1250和1280℃;而且焙烧球团矿的抗压强度分别提高到每个2746 N和每个2630 N.焙烧球团矿的微观结构研究表明:配加国产磁铁精矿后,焙烧球团矿中Fe₂O₃晶粒发育优良,晶粒间互联程度提高,晶粒粗大,孔隙率低,固结更加紧密.配加20%巴西赤铁精矿时,焙烧球团矿中Fe₂O₃晶粒基本连接成片,Fe₂O₃晶体发育良好.优化配矿是改善西澳超细粒磁铁精矿球团矿预热及焙烧性能的有效途径.      

巴西赤铁粉矿制取氧化球团及焙烧性能试验研究

为扩大生产球团矿的磁铁精矿资源,以国产磁铁精矿搭配巴西赤铁粉矿（粒度4～0mm）为原料,进行了制取氧化球团试验及其焙烧性能的试验。试验结果表明,该球团配料的成球性和焙烧性能优良,适合各种球团工艺生产氧化性球团矿。     

玛瑙山磁铁精矿氧化球团试验研究

以玛瑙山磁铁精矿为原料 ,进行了制备氧化球团的成球、焙烧和冶金性能等试验研究。试验结果表明 ,该精矿的上述各项性能优良 ,适合生产氧化球团矿。     

攀钢高炉大规模使用钒钛球团矿冶炼实践

对攀钢高炉大规模使用钒钛酸性氧化球团矿工业试验与生产实践进行了总结,结果表明,用钒钛球团矿大规模代替钒钛烧结矿试验与生产是成功的.当球团矿配比最高达到32%时,高炉没有出现不适应,利用系数提高,焦比降低.综合考虑攀钢炉料结构,＂高碱度低钛烧结矿＋全钒钛精矿酸性球团矿＂是最佳炉料结构,烧结中加入普通粉矿质量最佳,全钒钛磁铁精矿球团矿质量最好,钒钛磁铁精矿的最佳利用方式是生产球团矿,不适合于生产烧结矿.     

高钛型护炉球团矿焙烧工艺研究

TiO2含量在15%以上的高钛型护炉球团矿具有较好的市场需求。为了提升产品附加值,增强企业的竞争优势,西昌矿业公司希望利用自产钒钛磁铁精矿和钛精矿,生产这种高钛型护炉氧化球团矿。为此,进行了试验室试验和投笼试验,对高钛护炉氧化球团的矿物特征、焙烧工艺及固结机理进行了研究。结果表明,在适宜的造球参数及焙烧工艺条件下,生产TiO2含量为18%左右的高钛型护炉球团矿是可行的。     

高硫磁铁精矿反浮选脱硫工艺研究现状

为了从弱磁选铁精矿中分离磁黄铁矿,高硫磁铁精矿反浮选脱硫工艺受到了关注,笔者通过分析,介绍了磁黄铁矿分选的困难、磁黄铁矿的结构特点及其可浮性关系机理研究现状、高硫磁铁精矿反浮选脱硫药剂及其作用机理研究现状、高硫磁铁精矿反浮选脱硫工艺优化研究和高硫磁铁精矿反浮选脱硫试验及应用研究现状,针对高硫磁铁精矿反浮选脱硫工艺的研究方向提出了建议。     

添加剂强化钒钛磁铁精矿还原的研究

对硼砂添加剂强化钒钛磁铁精矿球团固态还原的机理进行了研究。结果表明,与无添加剂的球团还原比较,含添加剂的预氧化还原球团的金属化率较高,硼砂添加剂可明显促进钒钛磁铁精矿的还原。在还原过程中,含硼砂添加剂的钒钛磁铁精矿还原球团中的颗粒含有数量较多的微细孔洞,从而改善了钒钛磁铁精矿还原球团的显微结构,增强了气体反应物的扩散,有利于钒钛磁铁精矿的还原进行。     

承德钒钛磁铁精矿球团氧化固结机理与工艺制度的优化研究

本文采用各种主要分析和鉴定手段,研究了承德钒钛磁铁精矿球团氧化固结机理及氧化动力学;用数学方法,分析了影响球团矿质量的主要因素,并对因素取值进行了优化研究。 研究表明:900℃是承德钒钛磁铁精矿球团氧化动力学限制环节的转折点。因此,铁精矿球团氧化温度不宜高于1000℃;矿粉变细,氧化温度亦应降低。该矿球团氧化固结过程分为三个阶段,即氧化阶段,赤铁矿再结晶固结阶段和有液相参加下的赤铁矿“细粒化”及再结晶长大、晶粒连接成片阶段,球团合理的焙烧温度不得低于1250℃。优化计算得出了获得优质球团矿的最佳工艺参数组合.提出了改进承钢球团矿质量的建议。     

配加宣化当地精粉对球团矿质量影响的研究

造球原料中含适量CaO有利于提高球团矿强度,MgO有利于改善球团矿的冶金性能。宣化当地精粉含有部分CaO和MgO,为了充分利用本地资源,同时改善球团矿质量,我们在试验室模似宣钢生产条件进行了配加当地精粉的球团试验。探讨了这种含CaO、MgO精粉对球团矿质量的影响。     

高压辊磨预处理对超细粒度磁铁精矿粉球团性能的影响

 某磁铁精矿粉粒度虽然非常细,小于0.044mm的比例达到88%,但由于该矿粉颗粒形貌为板状、片状结构,故为中等成球性能矿粉。采用高压辊磨对该矿粉进行预处理后,其颗粒形貌发生很大变化,造球性能得到改善,膨润土单耗降低,但生球爆裂温度有下降趋势;高压辊磨预处理铁矿粉后,对改善预热球团矿的抗压强度效果不明显,但成品球团抗压强度得到提高。研究结果表明,高压辊磨预处理对细粒度磁铁精矿粉的造球性能及成品球强度有明显的改善效果。     

低温烧结时铁酸盐的矿物学研究

本文着重研究了钒钛磁铁精矿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 ,揭示了低温烧结的内在规律 ,为实现低温烧结提供了理论依据。     

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.     

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.     

粘结剂与铁精矿表面作用机理研究

本文从表面润湿热、表面电性及红外光谱测试入手，研究了“复合粘结剂”ＣＢ与磁铁矿颗粒表面作用机理。研究结果表明：ＣＢ化学吸附于颗粒表面，使矿粒表面亲水性增强，从而改善了磁铁矿的成球性，为成功地制备出优质铁精矿冷固球团创造了条件。     

Reduction swelling behaviour of haematite/magnetite agglomerates with addition of MgO and CaO

Abstract

The influence of three kinds of CaO and MgO additives (dolomite, burnt lime and serpentine) on the reduction swelling behaviour of haematite–magnetite (H–M) concentrates pellets was studied. Burnt lime and dolomite increased the reduction swelling index of H–M oxidised pellets, while the reduction swelling index was able to be reduced when serpentine was added. CaO accelerated the formation and growth of metallic iron whiskers and led to abnormal swelling of the magnetite briquettes, while MgO was able to be dissolved in wüstite and reduced the migration rate of Fe²⁺; therefore, there was no catastrophic swelling in either the haematite or magnetite briquettes. As far as H–M concentrate pellets were concerned, because the solubility of CaO in magnetite was greater than that in the primary haematite and the secondary haematite generated from magnetite during the oxidation was easy to be reduced to wüstite, there was abnormal swelling in the reduced H–M pellets with CaO addition.     

低铁高硅赤铁精矿对氧化球团性能的影响

为合理利用国内低铁高硅铁精矿、降低球团生产成本,研究了低铁高硅赤铁精矿对生球、预热球和焙烧球团性能的影响。结果表明,典型的低铁高硅赤铁精矿A较磁铁精矿有更好的润磨性能。赤铁精矿A的亲水性较磁铁精矿强,在保持生球水分不变且赤铁精矿配比较高的条件下(>10%),生球水分不足,生球质量随着赤铁矿配比的提高而变差。随着赤铁精矿A的配比由0提高到50%,预热球强度由588降低到196 N/个,焙烧球团抗压强度由3 425降低到1 368 N/个,赤铁精矿A配比不宜高于30%,适当提高焙烧温度有利于球团抗压强度的提高。配加低铁高硅赤铁精矿A的球团还原膨胀性能和还原性能均有一定程度改善。     

烧结和球团添加含硼铁精矿的研究

在实验室条件下，进行了烧结和球团配加含硼铁精矿的试验研究。研究表明；配加含硼铁精矿能提高烧结矿、球团矿的强度和还原性，降低球团矿的焙烧温度，改善烧结矿的生产指标。含硼铁精矿在具备条件的情况下是炼铁工业的经济合理的新型添加剂。     

Humic Substance-based Binder In Iron Ore Pelletization: A Review

Due to the reducing ability and bonding effect, a humic substance-based binder has been added into iron ore pellets, both as a reductant and a binder. However, humic substance-based binders were not commonly used in pelletization since some pelletizing results indicated they were not as good asbentonite or other binders. Thus, there were few detailed investigations using humic substance-based binders in pelletization before the 1980s. Funa, which is a type of humic substance-based binder extracted from lignite, was successfully invented and applied in cold-bonded pellets in China. Since the organic fraction in the humic substance-based binder is burnt away during heating, leaving no contaminant in pellets and improving the iron content of the pellets, humic substance-based binders were also gradually utilized in oxidized pellets. On the basis of Funa binder research, the extracting procedure of a humic substance-based binder was modified, and a composite binder named Modified Humic Acid (MHA)was prepared for oxidized pellets, especially for making Vanadium-Titanium (V-Ti) magnetite pellets, and achieved qualified V-Ti magnetite oxidized pellets in industrial testing. The behaviors of humic substance-based binders in wet balls, dry balls and fired balls were well investigated. Moreover, MHA binder was gradually tested in a lab for pelletization of several other types of iron ore concentrates, such as magnetite from different districts, specularite and fluxed hematite, and good quality pellets were obtained. A review of the development of a humic substance-based binder and its characteristics, preparing method, and behaviors in pelletizing were considered in this paper.