链篦机-回转窑铁矿氧化球团焙烧过程的分析

为了降低链-回-环系统球团矿焙烧过程的能耗,对某工业装置进行了平衡测试和分析,得到了流图。分析表明,传热不可逆损和燃烧不可逆损是系统损的主要部分。建立了气体质流量、床层空隙率、床高、球团直径、烟气中氧含量等运行参数与损的关系。结果表明,适当减小气体质流量、床高和球团直径,增大床层空隙率,可以减小损。在其它条件不变的情况下,当烟气中二氧化碳浓度为1.0%～9.0%,将空气消耗系数控制在1.6～2.0,可使损最小。     

链篦机-回转窑-环冷机氧化球团工艺设计及实践

探究链篦机-回转窑-环冷机氧化球团工艺设计过程中的设备选型。通过分析某公司180万t链篦机-回转窑-环冷机氧化球团工程中干燥机、高压辊磨机、混合机、圆盘造球机等设备的选型优化,使类似生产规模链篦机-回转窑-环冷机氧化球团工程的工艺设备选型更好地服务于生产。     

安钢120万t/a链篦机-回转窑氧化球团工程的设计特点

介绍了安阳钢铁集团公司120万t/a链篦机-回转窑-环冷机氧化球团生产线的设计特点及投产后的运行情况,详细论述了工艺流程及设备特点.投产以来,产品质量已达到设计要求,实现了快速达产.     

鞍钢200万t氧化球团链篦机-回转窑系统的设计

本文介绍了鞍钢200万吨氧化球团厂链篦机-回转窑生产线的工艺设计及特点。详细论述了球团生产过程中的原料准备、煤粉制备、干燥、配料、混合、造球、焙烧、冷却、成品等各个环节。鞍钢弓矿公司球团厂生产出铁品位65．5％、二氧化硅含量5％左右的球团矿,其产品质量达到了世界一流球团矿的技术标准。     

链篦机-回转窑氧化球团系统技术进步

介绍了山东淄博铁鹰钢铁有限公司60万t/a链篦机-回转窑氧化球团生产系统2010年以来进行的工艺优化、设备改造和操作调整。这一系列措施实施后,球团矿产、质量提高,能耗降低,较好地满足了高炉需求。     

链篦机-回转窑氧化球团生产线的工艺设计及生产实践

分析了邯郸钢铁公司年产200万t氧化球团生产线链篦机-回转窑的工艺设计与主要设备选型,介绍了该生产线的生产情况.     

从昆钢氧化球团工程试生产成功看我国氧化球团的技术进步

回顾了我国氧化球团生产技术的发展过程 ,阐述了一批大型链篦机—回转窑—环冷机工艺成功投产所带来的技术进步。通过介绍昆钢氧化球团工程 ,指出我国氧化球团工程技术已上了一个新的台阶 ,并总结了其成功经验     

氧化球团链篦机-回转窑用耐火材料的进展

综述了氧化球团链篦机－回转窑用耐火材料的发展历程．介绍了各个时期氧化球团链篦机－回转窑用耐火材料的特点及应用情况，并对氧化球团链篦机－回转窑用耐火材料的发展方向进行了探讨。     

莱钢矿建公司氧化球团链篦机-回转窑的设计特点

介绍了莱钢矿建公司25万t／a链篦机-回转窑氧化球团生产线的工艺设计及特点。     

Brazilian Iron Ore and Production of Pellets

Brazil is the second-largest producer of iron ore in the world. Brazilian richer superficial deposits are composed of brittle material with fine texture and significant amounts of fines are generated during mining and transport. Another type of ore found in this country is the itabirites that have lower iron contents. Beneficiation and concentration steps are required to prepare these materials for the pelletizing process. A general view of Brazilian types of iron ores, mines, and mining companies is given in this work. Special attention is given to pelletizing and the influence of mineralogical characteristics of different ores on the production and final properties of iron ore pellets.     

Cold Bonding of Iron Ore Concentrate Pellets

Iron ore concentrate pellets are traditionally hardened at high temperatures in horizontal grates and grate-kiln furnaces. However, heat induration requires tremendous quantities of energy to produce high-quality pellets, and is consequently expensive. Cold bonding is a low-temperature alternative to heat induration. Pellets can be cold bonded using lime, cement, sponge iron powder, and organic materials such as starch and flour. Cold bonding consumes less energy than heat induration, and has found favor for bonding self-reducing pellets and for refractory ores that are difficult to heat-treat. Herein, we review the principal cold bonding methods and their fundamentals.     

Pellets Prepared with Mechanically Activated Iron Ore

This work analyses pellets prepared with iron ore that has been mechanically activated by high energy ball milling. Pellet feed iron ore was submitted to high‐energy ball milling for 60 minutes, and the resulting material was analysed through measurements of particle size and specific surface area, as well as X‐ray diffraction. Pellets were prepared from this material. The pellets were heated at temperatures ranging from 1000 to 1250°C in a muffle furnace, and submitted to the maximum temperature during 10‐12 minutes. The samples were then tested regarding crushing strength, densification and porosity, and were examined in a scanning electronic microscope. The results were compared to those obtained with similar samples made from non‐milled pellet feed. It has been shown that through high‐energy ball milling of iron ore it is possible to achieve pellets presenting high densification and compressive strength at firing temperatures lower than the usual ones.     

Reduction-Swelling Behaviour of Pellets Bearing Iron Ore and Charcoal

Abstract

Self-reducing pellets containing iron ore and charcoal were reduced under argon at 1123, 1273, 1323, 1373, and 1423 K. The pellets were cold bonded with Portland cement. Pellets measuring 9.1 and 15.3mm diameter were tested. Thermogravimetry was used to follow the reduction process. X-ray diffraction was used to identify the present phases at the different steps of the reduction reaction. The change in volume was related to the reaction fraction, reaction temperature and the size of the pellet. Scanning electron microscopy images of the reduced pellet have shown that swelling is due to the formation of whiskers of iron during the wiistite to iron step of reduction. © 1998 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved.

Résumé

Des pelotes auto-reductrices faites de minerais de fer et de charbon ont été réduites sous atmosphère d'argon à temperatures de 1123, 1273, 1323, 1373,et de 1423K. Les pelotes furent liées à froid avec un ciment Portland. Des pelotes mesurant de 9,I a 15,3 mm furent étudiées. Afin d'étudier l'évolution de la réduction, des analises thermogravimetriques furent performées. La technique de diffraction de rayons X fut utilisée pour identifier les différentes phases présentes au cours des differentes étapes de la réaction de réduction. Le changement de volume fut relié à l'avancement de la réaction, la temperature de la reaction et à la taille de la pelote. Des observations avec microscope a balayage des pelotes ont révelé que le changement de volume était du a la formation de fibres de fer au cours de la wiistite de la reduction du minerais de fer.     

Utilization of High Sulfur Raw Materials in Iron Ore Pellets

Pyrite cinder and high sulfur magnetite were used as raw materials to produce iron ore pellets. Good qualities of green balls and fired pellets were obtained from the feed comprising 50% pyrite cinder and 50% high sulfur magnetite concentrate at a small scale. Small-scale tests were proven by pilot-scale tests. The high grade fired pellets, assaying 63.22% Fe, were analyzed, and the compressive strength of fired pellets was over 2500 N/pellet. The fired pellets possessed excellent metallurgical performances, such as reducibility index higher than 67%, reduction swelling index lower than 15% and low temperature reduction degradation index (+ 3.15 mm) higher than 1%, which can be used as the burden for blast furnace.     

Use of Iron Ore Fines in Cold-Bonded Self-Reducing Composite Pellets

The feasibility of producing direct reduced iron from cold-bonded, self-reducing composite pellets, constituted from beneficiated iron ore slime, coke, and different binders (dextrin, bentonite, calcium lignosulfonate, and carboxymethyl-cellulose [CMC]) was studied. This was done using a design of experiments approach. It was found that as-received beneficiated iron ore slime is suitable as a raw material for the production of self-reducing composite pellets with carboxymethylcellulose as the most suitable binder. Dry strengths in excess of 300 N/pellet were attained by curing the pellets under ambient conditions. The composite pellets reduced within 20 min to degrees of metallization in excess of 90% at 1100°C, with decrepitation indices significantly below 5%. The degree of metallization of composite pellets increased with an increase in reduction temperature (from 1000 to 1100°C), reduction time (20 min. vs. 40 min), and coke quantity (15% vs. 20%). CMC was identified as the most economical and suitable binder for the Sishen concentrate.     

添加熔剂对球团矿还原膨胀率的影响

在鞍钢现场的原料条件下,向铁精矿中添加含CaO、MgO等熔剂并研究其对原膨胀率的影响。结果表明:CaO恶化球团的还原膨胀性能,MgO能够很好地降低球团的膨胀率,并随着熔剂配比的增加而降低。当熔剂配比为1%时,镁石球团还原膨胀率指标最低,为11.83%,且比基准球团低1.2%;石灰石球团还原膨胀率指标最高,为14.93%且比基准球团高出1.93%。     

内配碳赤铁矿球团固结机理研究

以赤铁矿为原料,添加适量的固体燃料可以提高球团矿强度,大幅度降低焙烧燃耗,改善球团矿的冶金性能.研究碳对赤铁矿球团强度的影响,结合显微结构分析,揭示内配碳赤铁矿球团的固结机理.结果表明,内配碳赤铁矿球团焙烧过程中存在部分原生赤铁矿先被还原成磁铁矿或浮士体,然后再氧化成次生赤铁矿的过程.次生赤铁矿活性高,易发生迁移和扩散...