微波作用下高磷铁矿提铁脱磷的实验研究

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实验研究。从热力学和动力学方面研究了微波强化高磷铁矿提铁脱磷的作用机理,探讨了微波场中高磷铁矿提铁脱磷的影响因素和工艺条件。结果表明:微波可以加快铁矿石碳热还原反应速率,强化提铁脱磷效果;高磷铁矿在微波场中碳热还原,再经细磨和磁选,其脱磷率可达87.8%,收铁率可达90%。     

高磷铁矿石脱磷技术研究现状及发展趋势

高磷铁矿石的选矿已成为国内外的一大选矿技术难题,本文总结了当前国内外高磷铁矿脱磷工艺的研究现状及方法,从我国高磷铁矿选矿技术现状和高磷铁矿选铁脱磷工艺存在的问题进行了综述和分析,提出开发高磷铁矿石的提铁降磷工艺的发展方向及趋势.     

复合脱磷剂对微波焙烧高磷铁矿过程的影响

为实现高磷铁矿粉在烧结过程中气化脱磷,促进高磷铁矿的开发利用,试验选用鲕状高磷赤铁矿为原料,采用微波加热方式研究了复合脱磷剂成分及用量对气化脱磷率的影响。结果表明,煤种选用烟煤、配碳量为5%、SiO_2加入量为0.75%、CaCl_2加入量为1.5%、碱度为1.4时,能使高磷铁矿粉在微波场中气化脱磷率达到20.36%。通过X射线衍射仪(XRD)对焙烧产物进行检测得知,过量加入CaCl_2会产生Ca_5(PO_4)_3Cl,不利于气化脱磷的进行。     

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。     

高磷铁矿气化脱磷理论及试验研究

以高磷铁矿为研究对象,从氧势图、热力学计算、气化脱磷优势区图角度分析了气化脱磷的可行性,采用微型烧结试验研究了不同配碳量、添加剂配比对气化脱磷率的影响。理论分析表明,磷氧化物氧势线高于铁氧化物氧势线,难于还原,原料中加入碳后,碳颗粒周围存在局部的还原性,可以实现原料中磷的还原,加入添加剂,可以把原料中磷转化为含磷气体。试验研究表明,配碳量过低和过高均不利于脱磷,当配碳量为4%,按照一定配比加入Si O2+Ca Cl2后,气化脱磷率达到17%左右。     

生物质木炭用于鲕状高磷铁矿除磷

针对难处理的鲕状高磷铁矿,提出了首先采用高气化性生物质木炭制备含碳球团,然后通过直接还原-高温熔分的方法,成功实现了该铁矿的除磷提铁.直接还原实验采用管式炉.考察了还原温度、生物质木炭加入比例（碳氧摩尔比）和气氛等条件对样品还原行为的影响,并确定了适宜的还原条件为温度1373 K、配碳量0.9、时间15～25 min以及气氛P_CO2/P_CO=1:1.在此条件下,样品的金属化率和残碳质量分数分别在75%～80%和0.69%～0.11%的范围内.通过对该金属化球团的X射线衍射和扫描电镜-能谱分析发现:还原后样品中的主要物相为金属铁、磷灰石和硅酸三钙;磷没有被还原而仍以磷灰石的形式存在于脉石中.高温熔分实验采用Si-Mo棒高温箱式炉.实验结果得到磷质量分数为0.4%的铁样.在熔分体系中进一步添加相对质量为2%～4%的Na₂CO₃,可以得到磷质量分数在0.3%以下的铁样.基于以上分析,证明了采用生物质木炭用于高磷铁矿的除磷提铁是可行的.      

脱磷剂对高磷铁矿球团气化脱磷的影响

高磷铁矿由于磷含量过高,限制其大规模开发利用。通过XRD衍射仪分析高磷铁矿中磷的赋存状态,并基于FactSage7.2热力学计算结果的基础,采用配料造球、球团焙烧等手段,探究不同脱磷剂SiO_2和CaCl_2对高磷铁矿球团气化脱磷的影响。结果表明:高磷铁矿中磷的存在形式为Ca_5(PO_4)_3,加入脱磷剂后气化脱磷开始反应温度降低至815℃,在温度1 250℃,配碳5%的条件下,加入SiO_2和CaCl_2配比分别为0.8%、1.6%作为混合脱磷剂,气化脱磷效果最佳,脱磷率达22.1%。为高磷铁矿在球团焙烧过程中气化脱磷提供了新思路。     

高磷鲕状赤铁矿脱磷技术研究

为合理利用我国储量丰富的高磷鲕状赤铁矿,针对其矿物学特点,提出了利用直接还原法处理高磷鲕状赤铁矿提铁脱磷的技术思想.实验表明,通过控制渣相碱度、还原温度和内配碳比等,可提高铁的收得率和脱磷率.     

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%。     

高磷鲕状铁矿酸浸脱磷

研究了酸浸处理高磷铁矿脱磷及其影响因素.实验用鄂西鲕状高磷矿Fe的质量分数为51.7%,P的质量分数约0.5%,S的质量分数为0.34%.通过硫酸浸出,浸出矿中磷的质量分数降低至0.07%左右,而铁损只有0.18%,S的质量分数为0.35%,满足钢铁生产的要求.通过扫描电镜观察和能谱分析表征了高磷矿中磷的脱除,在实验酸度下能明显看出磷灰石溶解,而铁相基本不反应,并得到了热力学计算证明.实验确定了最佳的酸浸条件:浸出时间1 h,液固比100mL:8 g,酸度0.2 mol·L-1,振荡频率150 Hz.通过微波加热预处理,高磷铁矿中产生微裂纹,增加了矿石的比表面积,但是这并没有明显促进酸浸脱磷的进行.通过补酸的方式循环利用酸浸液处理高磷铁矿能得到较好的脱磷效果,脱磷率稳定在80%,能有效减少酸耗、保护环境.      

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.     

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。      

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.     

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。     

微波还原-磨矿磁选对鲕状赤铁矿提铁脱磷的影响

摘要：采用微波加热还原 磨选技术研究鲕状赤铁矿的提铁脱磷条件,且探索最佳磨选条件。在原矿粒度小于0.18mm占90%、配碳系数1.0、碱度系数0.8、脱磷剂用量15%（质量分数）的条件下,采用微波加热在950℃下还原30min获得金属化球团,对金属化球团进行破碎、研磨,考察磨矿粒度、磁选强度对铁粉铁品位、回收率、P含量、脱磷率的影响规律,并对还原样品、磁选后的铁粉和非磁性渣进行了扫描电镜、能谱和X射线衍射分析。研究结果表明,金属化球团在研磨粒度小于0.045mm占62.90%、磁选强度65mT条件下,可获得铁粉铁品位87.69%、回收率77.86%、P质量分数0.30%、脱磷率86.37%。     

鲕状赤铁矿微波加热还原提铁脱磷机制

采用微波加热还原鲕状赤铁矿内配碳球团,考察了还原温度、碱度及添加剂用量对球团含磷组元迁移的影响,对微波碳热还原提铁脱磷机制进行了分析。结果表明,随着还原温度的升高含磷组元逐渐被还原,当还原温度达到1 150℃以上时含磷矿物被大量还原,并且富集到还原铁中造成还原铁粉磷含量过高。在较低还原温度下,通过选择合适的碱度和脱磷剂用量,能有效地抑制含磷组元的还原,促进铁氧化物的还原和聚集。实验采用原矿粒度0.8 mm、碱度0.8、碳氧摩尔比1.0、钠盐添加剂用量20%(质量分数)、还原温度为950℃保温10 min的条件对物料进行还原,将还原物料研磨到0.074 mm在65 mT的场强下进行磁选可得到全铁质量分数82.79%、回收率86.49%、P质量分数0.34%的指标,所得到的还原铁粉杂质较少,而含磷物质主要以磷酸盐的形式存在于磁选渣中。     

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。     

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.