【作者】 陈敏；

【导师】 罗立群；

【作者基本信息】 武汉理工大学 ， 矿物加工工程， 2012， 硕士

【摘要】 我国鲕状赤铁矿资源丰富,远景资源量超过1×1010t,约占全国铁矿资源总量的1/9,由于鲕状赤铁矿嵌布粒度极细且含磷量较高,矿物组成和矿石结构及构造复杂,是国内外公认的难选铁矿石类型之一,目前这类铁矿资源基本没有得到开发利用。随着国内高品位富矿及易选矿资源的日趋枯竭,国内钢铁行业正面临着巨大的原料供应压力。研究鲕状赤铁矿资源的选矿技术,对于缓解我国冶金工业存在的铁矿石供需矛盾具有重大的实际意义。本文在对湖北某鲕状赤铁矿进行了矿物工艺学研究的基础上,采用磁化焙烧-弱磁选-反浮选的原则工艺流程进行了提铁降杂工艺研究,重点考察了磁化焙烧温度、磁化焙烧时间对磁化焙烧效果的影响,并对磁化焙烧前后的相关产物进行了显微镜下观察、统计和XRD定性与定量相关分析。结果表明：通过对磁化焙烧-弱磁选-反浮选工艺流程的研究,确定最佳工艺条件为：磁化焙烧温度为800℃,磁化焙烧时间为60min,磁化焙烧还原剂(煤粉)用量为8%；弱磁选粗选磁场场强为79.58kA/m,弱磁选精选磁场场强为63.66kA/m,弱磁选磨矿细度为-0.045mm占84.15%；反浮选控制pH=11.0～11.5,活化剂用量为50g/t,抑制剂用量350g/t,反浮粗选捕收剂用量1300g/t,反浮精选捕收剂用量650g/t。在此条件下进行得到了铁品位为60.24%、总回收率为74.54%的最终铁精矿,磷含量为0.28%,可以作为冶炼铁的配料,若要作为炼铁的原料,还需要进一步的试验研究以降低杂质P含量。显微镜下观察与统计发现：磁化焙烧的反应过程是由表及里,由外到内逐步转化的；矿石的粒度大小和粒度分布对磁化焙烧过程有直接的影响,矿石颗粒越细小,越有利于焙烧过程中还原反应的进行；磁化焙烧过程仅能改变铁的物相而不能改变含铁矿物的粒度及嵌嵌布关系,焙烧产物中含铁矿物的粒度及嵌布关系对焙烧前的试样具有继承性,鲕状结构并没有被破坏,这制约着鲕状赤铁矿磁化焙烧的效果。焙烧矿的XRD定量分析表明,磁化焙烧温度为800℃、磁化焙烧时间为60min时,生成强磁性的Fe304含量最高,且只发生轻微的过还原反应,只有少量的弱磁性的富氏体和弱磁性硅酸铁生成,焙烧效果较好。更多还原

【Abstract】 The oolitic hematite is abundant in our country and its prospective reserve is more than ten billion ton which accounts for1/9of the total iron ore resourees. However, this kind of iron ore resource around the world has not been widely exploited for its fine particle distribution, complicated structure, complex compostion and a high P content. With the high consumption of high grade ore for easy separation continually, steel industry is facing tremendous pressure from raw material supply. The job of exploring and processing the low grade and refractory hematite ore is quite urgent, which is propitious to ease the contradiction between supply and demand and has great practical significance.Based on the research of mineral technology of the oolitic hematite in Hubei, this paper mainly studies on magnetizing roasting-low intensity magnetic separation-reverse flotation flowsheet for high grade iron concentrate and mainly examines influence of magnetizing roasting temperature and time towards magnetizing roasting effect. Then through observation and statistics of roasted production and XRD qualitative and quantitative correlation analysis, the results show that:Through the reasearch of magnetizing roasting-low intensity magnetic separation-reverse flotation process, determine the optimum conditions as following: magnetizing roasting temperature for800degrees centigrade, magnetizing roasting time for60min, magnetizing roasting reducing agent amount for8percent; magnetic field stength of weak magnetic roughing separation for79.58kA/m, weak magnetic cleaning separation for63.66kA/m, grinding fineness of-0.045mm accounting for84.15percent; pH of reverse flotation for11.0～11.5, activating agent dosage for500g/t, inhibitor dosage for350g/t, collector dosage of1300g/t for reverse roughing flotation, collector dosage of650g/t for reverse cleaning separation. Based on those conditions, the result of magnetizing roasting-low intensity magnetic separation-reverse flotation closed-circuit test process is for: the iron grade of60.24%, the total recovery rate of74.54percent, phosphorus content of0.28percent for the final iron concentrate. The final iron concentrate can be used as ingredients for smelting iron. It needs further study to reduce P content.Observations and statistics for roasted production under optical microscope show that magnetizing roasting reaction is from outside to inside. The particle size and particle distribution of the crude ore has a direct influence on magnetizing roasting process. The smaller the particle size is, the easier the reducing reaction will occur. Magnetizing roasting process can only change iron phase rather than oolitic microstructure, which means that the magnetizing roasted ore has the same microstructure as the crude ore. This is the internal factor that restricts magnetizing roasting effect. XRD quantitative analysis of roasted ore shows that when magnetizing roasting temperature is800℃and magnetizing time is60min, there will be highest magnetite content generated and a small amout of weakly magnetic iron silicate generated. Meanwhile, there is only slight over-reducing reaction and only a small amount of weakly magnetic wustite generated, which means the roasting effect is good.更多还原