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。     

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。     

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。     

高磷鲕状赤铁矿煤基直接还原实验

采用XRD和SEM对高磷鲕状赤铁矿矿物的组成及矿相结构进行了研究分析,根据分析结果提出采用煤基直接还原-磁选工艺处理高磷鲕状赤铁矿,并对影响该工艺的因素进行了详细的实验研究与分析。结果表明:最佳工艺条件为还原温度1 250℃、还原时间30min、碳氧比1.8及碱度0.8,在此工艺条件下,可以得到产率为47.68%、铁品位为86.51%、铁回收率为92.94%、磷的质量分数为0.18%和金属化率为92.56%的磁选精矿以及磷回收率为92.88%的尾矿。     

高磷鲕状赤铁矿深度还原过程中磷的迁移规律

 针对鄂西某地高磷鲕状赤铁矿进行了深度还原技术研究,考查了还原温度、还原时间、配碳系数和CaO添加量对磷迁移规律的影响。结果表明：进入铁粉中磷的品位和回收率随着还原温度的升高和还原时间的延长而升高,随着配碳系数的增大先升高后降低,并在配碳系数为2.0时达到最大;而受CaO添加量的影响较小。还原物料的XRD和SEM分析表明大部分磷被还原为单质迁移进入了铁粉中。对高磷鲕状赤铁矿深度还原过程中磷的迁移规律进行了初步探索,为进一步研究高磷鲕状赤铁矿提供了一定的理论基础。     

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。     

鲕状赤铁矿特征及选冶技术进展

论述了鄂西高磷鲕状赤铁矿的资源状况、矿物组成、矿石结构、矿物工艺学特征,对处理、利用该类矿石存在的问题进行了分析,介绍了常用反浮选、强磁选、磁化焙烧-弱磁选、直接还原焙烧、酸浸及微生物浸出等选冶技术的现状,展望了高磷鲕状赤铁矿还原-磁选、磁选-絮凝脱泥-反浮选等选矿联合流程的发展趋势。     

鲕状高磷赤铁矿熔融还原过程脱磷技术研究

针对"宁乡式"鲕状高磷赤铁矿的矿物学特点,研究用熔融还原法处理"宁乡式"鲕状赤铁矿脱磷的技术。热力学及动力学分析和熔融还原脱磷实验表明,碱度、萤石比例等因素影响脱磷率。鲕状高磷赤铁矿熔融还原过程中配加CaO、CaF2脱磷效果显著,脱磷率最高可达97.3%。合适的二元碱度在1.8~2.2之间,CaF2的合理加入量在6%~9%。     

鄂西高磷鲕状赤铁矿直接还原焙烧同步脱磷机理

采用XRD和SEM分析方法研究了鄂西高磷鲕状赤铁矿添加脱磷剂后直接还原焙烧的产物及磁选后的最终产品.结果表明,还原焙烧过程中添加的脱磷剂除具有脱磷效果外,对铁的还原也有促进作用.脱磷剂可以使部分磷转化为易去除的可溶性磷酸盐,同时破坏鲕粒结构,使细磨-磁选后铁相易与脉石矿物分离从而达到脱磷效果,并且可以提高产品中铁的品位和回收率.     

红土镍矿含碳球团还原焙烧-磁选试验

为提高红土镍矿金属品位及回收率,采用含碳球团还原焙烧-磁选分离工艺对镍品位为1．45％（质量分数,余同）的红土镍矿进行了处理,研究了还原温度、配碳量、还原时间以及磁选工艺对Ni、Fe品位和回收率的影响。试验结果表明：随着还原温度和配碳量的增加,Ni、Fe品位及回收率均会增加,其中温度的影响最大,配碳量次之,时间最小。1...     

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.     

Dephosphorisation of high phosphorus oolitic hematite by carbon composite pre-reduction and fast melting separation

High phosphorus oolitic hematite deposit is a kind of refractory iron ore resource of huge amount. At present, it is difficult to be utilised by traditional physical and chemical technology efficiently and economically. A novel process for utilisation of the high phosphorus oolitic hematite based on carbon composite pre-reduction and fast melting separation has been put forward in the paper. High grade pig iron nugget of low phosphorus could be obtained in the present research. The influence of experimental conditions, such as pre-reduction temperature, C/O (molar ratio) and basicity, on the dephosphorisation behaviours was studied in detail. The thermodynamic basis and reduction and melting separation process were also analysed. The phosphorus content in the iron nugget decreased with the increasing of basicity and increased with the increasing of C/O. The optimum parameters were pre-reduction temperature of 1200°C for 30?min, C/O of 0.95 and basicity of 1.7. After melting separation of molten iron and slag at 1400°C for 10?min, the iron nugget containing 0.02?wt-% [P] would be obtained. The dephosphorisation degree and iron yield in the form of iron nugget were 97.5% and 96.9% respectively. The iron nugget may be directly used as the raw materials of steelmaking from the view point of its high grade.     

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。     

温度对高磷鲕状赤铁矿含碳球团直接还原影响

对高磷鲕状赤铁矿含碳球团直接还原进行了研究。结果表明,1100℃以下时,提高温度可以显著提高球团金属化率;1100℃以上时,继续提高温度对球团金属化率影响不大。球团金属化率越高,磁选精矿铁品位越高。还原温度不仅显著影响球团的金属化率,还影响金属铁相的长大及磁选效果。因此,控制适宜的温度对高磷鲕状赤铁矿含碳球团直接还原至关重要。     

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.