隐晶质鲕状赤铁矿磁化焙烧过程中铁物相转变规律

摘要：鲕状赤铁矿具有含磷高、易泥化,铁与脉石矿物呈鲕状嵌布结构等特点,常规的重选和浮选等工艺难以取得较好的选矿指标。磁化焙烧-磁选工艺是利用高磷鲕状赤铁矿最有效的手段之一。X射线衍射（XRD）分析结果表明,在750℃的条件下,焙烧矿中磁铁矿的相对质量分数最大。焙烧温度高于800℃会发生过还原现象,生成富氏体,不利于焙烧矿的弱磁选。光学显微镜分析表明磁化焙烧过程不会破坏鲕状赤铁矿的鲕粒结构,只发生铁物相的转变。赤铁矿到磁铁矿的晶型转变由表及里,但是多数鲕状赤铁矿颗粒不会完全磁化,磁化焙烧效果与粒度有关。全铁品位为43.74%的矿样,在焙烧温度750℃、焙烧时间60min的条件下,弱磁选可得到全铁品位为55.42%,铁回收率为85.66%的人工磁铁矿,磁铁矿转化率在90%以上。     

微波作用高磷铁矿提铁脱磷的研究

为充分利用高磷铁矿,进行了微波作用高磷鲕状赤铁矿煤基碳热还原提铁脱磷的研究.高磷铁矿经微波作用碳热还原、细磨和磁选,其脱磷率达到87.8%,收铁率达到90%.本文从晶格能、热力学和动力学方面分析了微波强化高磷铁矿提铁脱磷的作用机理,探讨了微波应用于高磷铁矿提铁脱磷的可能性.结果表明:微波可以加快铁矿石碳热还原反应速率,...     

云南某高磷鲕状赤铁矿提铁降磷试验研究

云南某鲕状赤铁矿磷含量高达0.87%,铁品位为45.14%。对此矿石进行单一的强磁选及反浮选试验研究,结果表明都不能获得磷品位低于0.2%,铁品位较高的铁精矿。采用强磁-反浮选及脱泥-反浮选均能获得磷品位低于0.2%,铁品位高于52%的铁精矿。脱泥-反浮选具有投资成本低,流程结构简单的优势,推荐采用此流程处理该矿石。该研究对开发此类高磷鲕状赤铁矿具有一定的借鉴意义。     

高磷鲕状铁矿直接还原?磁选提铁降磷扩大试验研究

为给回转窑工业试验提供参数,以小型试验最佳结果为基础,进行了高磷鲕状铁矿煤基直接还原?磁选提铁降磷扩大试验。结果表明,在最佳的条件下可获得铁品位94.17%、铁回收率77.47%以及磷质量分数0.08%的粉末还原铁,推荐的回转窑工业试验初始条件为:石灰石用量（质量分数）28%、无烟煤用量（质量分数）16%、还原温度1300 ℃,还原时间3 h。采用XRD以及SEM-EDS研究了无烟煤的作用机理,发现无烟煤用量增加,促进了浮氏体、镁铁尖晶石的还原以及铁颗粒长大,从而提高了铁的回收效果,但过多的无烟煤通过增强还原气氛及其带入的灰分消耗了石灰石,使铁矿物中的磷以及磷灰石还原成单质磷并与铁颗粒形成铁磷合金。      

Recovery of metallic iron from high phosphorus oolitic hematite by carbothermic reduction and magnetic separation

Abstract

This study aims to provide theoretical and technical basis for economical and rational use of high phosphorus oolitic hematite. Following physical, chemical and microscopic characterisation of high phosphorus oolitic hematite ore the feasibility of separation of phosphorus and metallic iron by reduction roasting and magnetic separation process were investigated. The results indicate that such a process is a feasible and efficient method for iron and phosphorus separation of high phosphorus oolitic hematite. The recovery of metallic iron and dephosphorisation rate is relatively low without additives but is significantly improved by appropriate CaO and Na₂CO₃ addition. With 8%CaO and 3%Na₂CO₃ the recovery of metallic iron and dephosphorisation rate reach 95.1 and 94.0% respectively.     

Phosphorus Removal and Iron Recovery from High-Phosphorus Hematite Using Direct Reduction Followed by Melting Separation

To efficiently utilize high-phosphorus oolitic hematite resources, a method using direct reduction followed by melting separation was proposed. In this study, direct reduction behavior of the ore–char briquette and the melting separation behavior of the reduced briquette were investigated. Direct reduction test results show that under investigated conditions, the briquette reached a metallization rate of 80%–88% and a residual carbon value of 0.11–4.85 wt%,and apatite layers were fragmented into tiny particles, some of which were embedded in metallic iron phase. Melting separation test results show that residual carbon can significantly influence the iron recovery rate. For metallic briquettes with the abovementioned qualities, the iron recovery rate ranged from 75% to 98%. To control the phosphorus content in molten iron to be nearly 0.4 wt%, an iron recovery rate of 80% was shown to be adequate.     

高磷鲕状赤铁矿直接还原法脱磷技术的试验研究

为了经济、合理地利用高磷赤铁矿资源,在掌握试验用高磷鲕状赤铁矿理化特性和微观特性的基础上,采用直接还原法进行了固态直接还原+高强度磁选和直接生产珠铁2种工艺的试验研究。试验结果表明,高温度、低碱度以及高配碳量有利于铁矿石中磷灰石还原进入铁水中,不利于磷的脱除;通过工艺参数的优化,采用固态还原焙烧-磁选工艺,高磷赤铁矿脱磷率能达到60%以上,而采用珠铁工艺,其脱磷率能够达到80%以上。为合理高效地处理高磷鲕状赤铁矿奠定理论基础和技术依据。     

Slag/metal Separation Process of Gas-reduced Oolitic High-phosphorus Iron Ore Fines

Slag/metal separation process of the highly reduced oolitic high-phosphorus iron ore fines was investigated. Samples were prepared using the reduced ore fines （metallization rate： 88%） and powder additives of CaO and Na2CO3. Slag/metal separation behavior tests were conducted using a quenching method and the obtained metal parts were subjected to direct observation as well as microstructure examination with SEM and EDS; iron recovery and phosphorus distribution tests were conducted using a Si-Mo high temperature furnace and the obtained metal parts were examined by ICP-AES analysis and mass measurement. Thermodynamic calculation using coexistence theory of slag structure was also performed. Results show that temperature for slag/metal separation must be higher than 1823 K and a satisfying slag/metal separation of the highly reduced ore fines needs at least 4 min; phosphorus con- tent of hot metal is mainly determined by thermodynamics; temperature of 1823-1873 K and Na2CO3 mixing ratio of about 3 % are adequate for controlling phosphorus content to be less than 0.3 mass% in hot metal; temperature, time and Na2CO3 mixing ratio do not have significant effect on iron recovery, and iron recovery rate could be higher than 80% as long as a good slag/metal separation result is obtained.     

Direct Reduction of High-phosphorus Oolitic Hematite Ore Based on Biomass Pyrolysis

Direct reduction of high-phosphorus oolitic hematite ore based on biomass pyrolysis gases(CO,H_2,and CH_4),tar,and char was conducted to investigate the effects of reduction temperature,iron ore-biomass mass ratio,and reduction time on the metallization rate.In addition,the effect of particle size on the dephosphorization and iron recovery rate was studied by magnetic separation.It was determined that the metallization rate of the hematite ore could reach 99.35% at iron ore-biomass mass ratio of 1∶0.6,reduction temperature of 1 100℃,and reduction time of 55 min.The metallization rate and the aggregation degree of iron particles increase with the increase of reduction temperature.The particle size of direct reduced iron(DRI) has a great influence on the quality of the iron concentrate during magnetic separation.The separation degree of slag and iron was improved by the addition of 15 mass% sodium carbonate.DRI with iron grade of 89.11%,iron recovery rate of 83.47%,and phosphorus content of 0.28% can be obtained when ore fines with particle size of-10 μm account for 78.15%.     

高磷鲕状赤铁矿铁磷分离试验研究

对高磷鲕状赤铁矿进行了显微结构研究,采用添加脱磷剂直接还原焙烧-磁选工艺进行了铁和磷分离试验,研究了焙烧温度、内配碳量、添加剂配比对铁、磷分离主要技术指标的影响。结果表明:磷主要以磷灰石的形态嵌布在鲕状结构中,部分与赤铁矿形成环状间层,层间的厚度变化范围在3~15μm之间;在焙烧温度1 000℃、内配碳量6%、添加剂配比10%的优化工艺条件下,通过球磨-磁选试验可得到含铁品位大于85%、含磷量在0.15%~0.20%之间的优质还原铁粉和含磷为3.5%~4%的富磷渣。     

恩施高磷鲕状赤铁矿煤基直接还原的试验

 为最大限度地利用恩施黑石板地区的铁矿资源,先通过XRD、扫描电镜、金相显微镜等手段研究了它的矿相组成和结构,得知其主要成分是赤铁矿和石英,矿的显微结构以鲕粒群簇为主,鲕粒中赤铁矿与磷灰石呈环带状分布。矿相结构决定了用一般的选矿方法分离铁、磷非常困难,为此用实验室煤基直接还原法研究了还原温度、还原时间、煤种、添加剂、磁选工艺等对精矿中铁品位和铁回收率的影响规律,得到了提高还原率的合理工艺参数：以哈密煤为还原剂,焙烧还原温度1573K,还原时间40min,一段磨矿时间15min,磁场强度280kA/m。采用此工艺可使精矿产率、铁品位、铁回收率分别达到43.21%、 95.77%和92.18%,磷品位由0.76%降至0.097%。该研究为该地区高磷鲕状赤铁矿工业化的开发利用提供了依据。     

Composite Micropelletization of Slime for Iron Grade and Recovery Maximization to Generate Pellet Feed Materials

The present research work deals with the upgradation of iron ore slime by maximizing its iron grade and recovery so that it can be used in downstream iron making processes. Slime contains significant amount of iron value and is still being dumped as waste which also requires large area for dumping. Slime (45–48 wt% Fetotal) after converting into dry powder was mixed with desired amount of reductant (NCC), and the mixture was converted into composite micropellets (+ 1 to − 6 mm) by using disc pelletizer. Produced composite micropellets were subjected to reduction at desired reduction conditions. Temperature, NCC dosage and time were the prime parameters whose effect on iron grade and recovery was investigated. Wet magnetic separation tests were performed on reduced samples to upgrade the iron content. Maximum value of iron grade and recovery was achieved at 900 °C with 11% of NCC for 60 min. After magnetic separation, iron content and recovery in the magnetic concentrate were 57.27% and 60%, respectively. This route of reduction for steel plant generated slime may be a helping hand in the usage of slime to prepare magnetic concentrate-based pellet feed materials.     

Influence of Mechanical Activation on Acid Leaching Dephosphorization of High-phosphorus Iron Ore Concentrates

High pressure roll grinding (HPRG)and ball milling were compared to investigate the influence of me-chanical activation on the acid leaching dephosphorization of a high-phosphorus iron ore concentrate,which was man-ufactured through magnetizing roasting-magnetic separation of high-phosphorus oolitic iron ores.The results indica-ted that when high-phosphorus iron ore concentrates containing 54·92 mass% iron and 0·76 mass% phosphorus were directly processed through acid leaching,iron ore concentrates containing 55·74 mass% iron and 0·33 mass%phosphorus with an iron recovery of 84·64% and dephosphorization of 63·79% were obtained.When high-phosphor-us iron ore concentrates activated by ball milling were processed by acid leaching,iron ore concentrates containing 56·03 mass% iron and 0·21 mass% phosphorus with an iron recovery of 85·65% and dephosphorization of 77·49%were obtained.Meanwhile,when high-phosphorus iron ore concentrates activated by HPRG were processed by acid leaching,iron ore concentrates containing 58·02 mass% iron and 0·10 mass% phosphorus were obtained,with the iron recovery reaching 88·42% and the dephosphorization rate reaching 88·99%.Mechanistic studies demonstrated that ball milling can reduce the particle size,demonstrating a prominent reunion phenomenon.In contrast,HPRG pretreatment contributes to the formation of more cracks within the particles and selective dissociation of iron and P bearing minerals,which can provide the favorable kinetic conditions to accelerate the solid-liquid reaction rate.As such,the crystal structure is destroyed and the surface energy of mineral particles is strengthened by mechanical ac-tivation,further strengthening the dephosphorization.     

白云鄂博矿硫的分布特性及降硫的研究进展

文章对白云鄂博矿中硫的分布情况进行考察,并进行降硫的系列试验研究,可使白云鄂博氧化矿弱磁选铁精矿中的w(S)由1.02%降到0.33%,铁精矿产率损失5.33%;磁铁矿弱磁选铁精矿中的w(S)由1.72%降到0.48%,铁精矿产率损失3.28%,基本达到课题目标(铁精矿中w(S)0.4%,铁精矿产率损失小于8%),但降硫后产生的硫精矿(产率较高,硫品位低、铁品位高)再处理尚无有效的办法。     

Reduction Roast and Magnetic Separation of Oxidized Iron Ores for the Production of Blast Furnace Feed

Abstract

Low grade oolitic iron ore from the Aswan locality, assaying 45.23% Fe and 23.93% insoluble residue, was tested for concentration using reduction roasting and subsequent low intensity magnetic separation for the production of blast furnace feed. The ore is a low grade, high phosphorus, and high alumina oolitic hematite. Fine grinding of the ore was found to be imperative due to the fine dissemination characteristics of the ore. The application of reduction roasting-low intensity magnetic separation process for high grade concentrate production and minimum hot metal costs was investigated. The studies included the use of gaseous reductants such as H₂ or CO, and the different parameters affecting the process were verified. Optimization of the process was demonstrated on a bench scale. Quality magnetic concentrates assaying 59.6% FE with recoveries of about 90% were obtained from a run of mine ore assaying 45.23% Fe.

Réesumé

On a évalué la concentration de minerai de fer oolithique de basse qualité de la localité d'Aswan, essayant à 45.23% Fe et 23.93% de résidus insolubles. On a utilisé le grillage par réduction et une séparation magnétique subséquente à basse intensité pour la production d'alimentation de haut fourneau. Le minerai est une hématite oolithique de basse qualité, haute en phosphore et en oxyde d'aluminium. On a trouvé que le meulage fin du minerai était impératif dû aux caractéristiques de dissémination fine du minerai. On a étudié l'application du procédé de grillage par réduction-séparation magnétique, à faible intensité, a la production de concentré de haute qualite et des couts minimums de métal chaud.

L'etude inclue l'utilisation d'agents réducteurs gazeux tels que H₂ ou CO. On a vérifié les différents parametres affectant le procede. On a optimise le procédé à l'echelle du laboratoire.     

江西某铁矿回收铁的试验研究

对于磁铁矿和赤铁矿混合型石英脉铁矿,磁浮工艺是成熟的.针对该矿嵌布粒度细,品位低的特点,利用粗精矿磨矿提高磁铁矿精矿品位和浮选入选品位,在原矿铁品位22％情况下,试验获得弱磁铁精矿品位大于65％,反浮选铁精矿品位大于58％,综合铁回收率大于50％.     

大红山某铁矿提铁降硅选矿工艺的优化

大红山某铁矿样原来采用"磁选粗选+再磨(90%-200目)+磁选、重选精选+精选尾矿重选"的流程方案,由于铁精矿要用管道运输,细度要求达到80%-325目,所得铁精矿还需再磨,因此有必要考虑在更细再磨条件下的选矿试验,最终确定采用磁选粗选+再磨(80%-325目)+磁选精选+精选尾矿重选(摇床或离心机)流程,得到了较好的选矿指标。     

高磷鲕状赤铁矿磷的存在形态及脱磷机理

 针对高磷鲕状赤铁矿石矿物结构复杂导致的脱磷困难现状,为实现深度脱磷的目的,探索矿物还原过程中磷的形态及微观脱磷过程。以铁品位为44.78%、磷的质量分数为0.92%的高磷鲕状赤铁矿为研究对象,根据其面扫描电镜及矿相结构图可知,矿物之间嵌布紧密、逐层形成鲕状结构,石英、鲕绿泥石与赤铁矿等互相包裹,磷元素集中分布在鲕粒内部的氟磷灰石中。通过对焙烧产物做扫描电镜(SEM)及能谱分析(EDS),对高磷鲕状赤铁矿脱磷机理进行研究。研究结果表明,当YM-1脱磷剂质量分数为16%,还原过程中鲕状结构被破坏,金属铁逐渐从鲕粒中析出聚集,脉石与铁颗粒分离明显,磷化为不同形态被脱除。磁选后尾矿、铁分离完全,磷元素几乎全部进入尾矿,添加复合脱磷剂YM-1焙烧磁选后铁精矿的铁品位为90.16%,铁回收率为91.25%,磷质量分数为0.056%,脱磷率为93.91%。铁精粉各项指标满足工业冶炼要求。     

Innovative Method for Separating Phosphorus and Iron from High-Phosphorus Oolitic Hematite by Iron Nugget Process

This study puts forward a new method to separate phosphorus and iron from high-phosphorus oolitic hematite through iron nuggets process. Firstly, the physical, chemical, and microscopic characteristics of high-phosphorus oolitic hematite are investigated. Then, the reaction mechanisms of high-phosphorus hematite together with feasibility to separating phosphorus and iron by iron nugget process are discussed. Meanwhile, the experiments of high-phosphorus hematite used in rotary hearth furnace iron nugget processes are studied as well. The results indicate that the iron nugget process is a feasible and efficient method for iron and phosphorus separation of high-phosphorus oolitic hematite. The phosphorus content in iron nuggets is relatively low. Through the optimization of process parameters, the lowest of phosphorus in iron nuggets is 0.22  pct, the dephosphorization rate is above 86  pct, and the recovery of Fe is above 85  pct by the iron nugget process. This study aims to provide a theoretical and technical basis for economical and rational use of high-phosphorus oolitic hematite.     

白尖铁矿可选性试验研究

白尖铁矿的矿物组成和酒钢桦树沟铁矿的矿物相同,但白尖铁矿中的菱铁矿和褐铁矿的含量都明显高于桦树沟矿,而且白尖铁矿各主要铁矿物矿物的嵌布粒度细,比桦树沟铁矿更难选。实验室中白尖铁矿的最佳焙烧条件组合为焙烧温度为700℃、焙烧时间为100 min、催化剂用量为6%时,焙烧磁选精矿品位能达到56.36%、铁回收率能达到95.18%的实验室指标,但明显差于桦树沟铁矿的实验室焙烧指标。通过酒钢竖炉投笼焙烧后白尖铁矿,在磨矿细度为-200目85%时,经过一粗两精三段弱磁流程选别试验,可获得精矿品位54.11%、精矿产率66.22%、铁回收率82.68%的选别指标,该指标明显低于桦树沟矿的焙烧磁选的选别指标。