某鲕状赤铁矿流化床燃煤还原焙烧-磁选研究

运用小型循环流化床锅炉,针对铁品位为49.20%、磷质量分数为1.16%的湖北某鲕状赤铁矿进行磁化焙烧-磁选试验研究.试验结果表明,将粒径为106～150 μm的鲕状赤铁矿在700 ℃下焙烧15 min,选取磨矿后粒径在74 μm以下的颗粒质量分数为85%的焙烧矿物,运用湿式磁选管在139.22 kA/m的磁场强度下对筛选后的焙烧矿物进行磁选抛尾,可以获得铁品位为55.12%、全铁回收率为70.11%、磷质量分数为0.67%的铁精矿.研究表明,运用循环流化床局部还原性气氛高速磁化焙烧铁矿石是可行的,运用该磁化焙烧-磁选工艺流程可以达到一定的提铁降磷效果.     

河北某鲕状(菱)赤铁矿选矿试验研究

对河北某地含铁品位38.57%的鲕状(菱)赤铁矿进行了选矿试验研究,考察了该矿石的工艺矿物学特征,重点研究了采用磁选、浮选、磁化焙烧.弱磁选等选别工艺的分选效果,试验结果表明磁化焙烧-弱磁选工艺是分选此类难选铁矿石的有效方法.在温度750℃,焙烧时间80min,煤粉配比5%的最佳焙烧条件下,焙烧矿经弱磁选可以获得精矿铁品位为59.94%.回收率84.87%的良好指标,并通过XRD分析对磁化焙烧的反应机理进行了初步的探讨.     

鲕状赤铁矿选矿与脱磷技术动态

鲕状赤铁矿铁品位高、储量大,因其特殊的结构且含磷较高,成为国内外选矿技术的难点之一.对鲕状赤铁矿的选矿工艺从直接入选、磁化焙烧-磁选、深度还原3类进行了系统归纳和总结,并介绍了3类工艺的分选机理.指出直接入选能耗低,污染少,但对磨矿细度有要求,矿石泥化严重;磁化焙烧-磁选是目前处理鲕状赤铁矿行之有效的办法,精矿指标较好,但磷含量较高;深度还原法处理鲕状赤铁矿,能够进一步提高精矿指标,但能耗高、工艺复杂.此外,从物理法、化学法和微生物法3个方面评述了鲕状赤铁矿有害杂质磷的脱除,建议结合技术经济来考察和分析其脱磷效果.     

鲕状赤铁矿磁化焙烧—磁选—反浮选降磷试验

鄂西宁乡式鲕状赤铁矿嵌布粒度极细,SiO2、Al2O3、P等杂质含量高,用其生产的铁精矿很难达到冶炼要求.针对铁品位为43.76%,磷含量为0.84%的鄂西鲕状赤铁矿进行提铁降磷试验研究,通过对磁化焙烧温度、磁化焙烧时间、还原煤的配比等影响因素的条件试验,确定在焙烧时间60 min,焙烧温度750℃,还原煤11%(质量比)的最佳焙烧条件.焙烧产品磨矿至-0.038 mm占80.54%、用永磁选机进行弱磁选,获得了铁品位54.10%、铁回收率93.19%、磷含量0.80%的粗铁精矿.进行反浮选药剂制度试验,得到了铁品位58.95%、铁综合回收率80%、磷含量0.50%的铁精矿,其最佳浮选药剂制度为NaOH 750 g/t,淀粉800 g/t,石灰500 g/t,RA-715 750 g/t,G310 107.73 g/t,浮选温度30℃.在此浮选制度下,进行一粗一精试验,精选石灰和捕收剂用量减半,可得铁品位59.87%,磷含量降至0.28%,综合回收率71.08%,综合试验结果表明,本文探索的工艺流程具有很大的可行性,能够为鲕状赤铁矿的选矿利用提供参考.     

鲕状赤铁矿“磁化焙烧-晶粒长大-磁选”新工艺研究

基于宣龙式鲕状赤铁矿嵌布粒度极细、结构复杂等特点,进行了磁化焙烧-晶粒长大-磁选新工艺研究。在焙烧温度为800℃,煤粉配比10%,焙烧时间45min的条件下,使赤铁矿还原焙烧成磁铁矿,经过弱磁选,可得到铁精矿品位62.5%,回收率85.5%的良好选矿技术指标。通过一系列观测手段及相关理论说明,证实了磁铁矿晶粒能够长大。     

低品位铁矿石流化焙烧-磁选提质试验研究

针对我国低品位铁矿石嵌布粒度极细,成分复杂,难提难选的现况,运用循环流化床和磁选管进行劣质铁矿石的流化焙烧 磁选试验研究,试验采用CO、N2的混合气体营造还原性气氛（其中CO体积分数为10%）,将粒径为1 mm以下的新疆某低品位铁矿石（原矿铁品位为9.63%）于850 ℃焙烧10 min,得到强磁性的磁铁矿,将焙烧产物破碎细磨（磨至200 目以下占75%）,利用湿式磁选管在71.66 kA/m的磁场强度下进行弱磁选抛尾,可以得到铁精矿品位为46.25%,全铁回收率为25.52%的选矿指标.研究表明,运用循环流化床焙烧-弱磁选的方法提质铁矿石,可以有效地减少焙烧时间,在保证选矿达标的基础上,有效地降低生产周期.     

新材料与新工艺

难选铁矿流态化磁化焙烧成套技术获突破我国难选铁矿流态化磁化焙烧成套技术取得突破。低品位难选铁矿石资源利用,对打破国外垄断、缓解我国铁矿石供应紧张的意义十分重大。磁化焙烧是低品位难选铁矿利用的有效方     

助磨剂对鄂西高磷鲕状赤铁矿磨矿的影响

鄂西高磷鲕状赤铁矿在微细粒磨矿时黏度非常高,严重影响磨矿效率,导致磨矿能耗大幅上升。用助磨剂六偏磷酸钠和三聚磷酸钠对鄂西高磷鲕状赤铁矿进行降黏度磨矿试验。结果表明,添加两种助磨剂均可降低矿浆的黏度,助磨剂添加量为0.2%时降黏和助磨效果最佳;助磨剂使球磨机的生产能力得到显著提高,其相对增量最高可达144%,磨矿时间为5min时助磨效果最佳。添加助磨剂后磨矿产品中粒度小于38μm的颗粒含量明显增加,两种助磨剂都能有效降低磨矿的能耗,最大能耗降幅为57.14%。     

鲕状赤铁矿原料粒度对深度还原效果及铁颗粒形貌的影响

采用化学分析、扫描电子显微镜(SEM)和工艺矿物学参数自动测试系统(BPMA),考察了鲕状赤铁矿原料粒度对深度还原效果及铁颗粒粒度分布、微观形貌等特征的影响.结果表明:降低原料粒度有利于金属化率和选别指标的提高,且提高的速率随原料粒度的减小逐渐增大;原料粒度越小,还原产物中铁颗粒粒度越大;在铁颗粒粒度频率分布方面,小粒径铁颗粒占主体,并随着粒径的增大,铁颗粒的粒度频率快速降低;还原产物中铁颗粒的形状主要以类球状、块状、棒状和链状分布,并随着原料粒度的增大,还原产物中铁颗粒的形貌愈加复杂.降低原料粒度有利于鲕状赤铁矿深度还原效果的提高和铁颗粒的生长.     

鲕状赤铁矿悬浮焙烧的粒度影响研究

研究了+100,100~74,74~45,-45μm 4个不同粒级对重庆巫山某鲕状赤褐铁矿悬浮焙烧过程的影响,并通过扫描电镜及能谱分析、磁性分析、X射线衍射分析、热力学分析等手段对其机理进行研究.结果表明:悬浮焙烧前后,矿物颗粒的微观形貌及嵌布特征并未发生明显变化;悬浮焙烧后,鲕状赤褐铁矿中的弱磁性铁矿物可以转变为强磁性铁矿物,除-45μm粒级外,其他粒级物料的比磁化率和磁化强度显著提高,且物料颗粒越细,其比磁化率和磁化强度就越高.鲕状赤褐铁矿石中的赤铁矿转变成磁铁矿,当物料粒度在-45μm时,有FeO相存在,说明发生了过还原反应.在一定温度条件下,赤铁矿很容易被还原为磁铁矿,且有稳定的Fe3O4相存在.因此,控制好焙烧物料的粒度对于获得较好的悬浮焙烧质量产品以及提高焙烧效率至关重要.     

Application of multi-stage dynamic magnetizing roasting technology on the utilization of cryptocrystalline oolitic hematite: A review

A large number of studies have shown that oolitic hematite is an iron ore that is extremely difficult to utilize because of its fine disseminated particle size, high harmful impurity content and oolitic structure. To recover iron from oolitic hematite, we developed a novel multistage dynamic magnetizing roasting technology. Compared with traditional magnetizing roasting technologies, this novel technology has the following advantages: firstly, the oolitic hematite is dynamically reduced in a multi-stage roasting furnace, which shortens the reduction time and avoids ringing and over-reduction; secondly, the novel dynamic magnetizing roasting technology has strong raw material adaptability, and the size range of raw materials can be as wide as 0–15 mm; thirdly, the roasting furnace adopts a preheating-heating process, and the low-calorific value blast furnace gas can be used as the fuel and reductant, which greatly reduces the cost. The actual industrial production data showed that the energy consumption in the roasting process can be less than 35 kg of standard coal per ton of raw ore. The iron grade of the concentrate and iron recovery reached 65% and 90%, respectively.     

Effect of coal levels during direct reduction roasting of high phosphorus oolitic hematite ore in a tunnel kiln

The effect of coal levels on phosphorus removal from a high phosphorus oolitic hematite ore after direct reduction roasting have been investigated. Raw ore, coal, and a dephosphorization agent were mixed and the mixture was then roasted in a tunnel kiln. The roasted products were treated by two stages of grinding followed by magnetic separation. XRD and SEM–EDS examination of the products was used to analyze differences in the roasted products. The results show that coal is one of the most important factors affecting the direct reduction roasting process. When the inner coal levels increased from 0% to 15% the iron grade decreased linearly from 94.94% to 88.81% and the iron recovery increased from 55.94% to 92.94%. At the same time the phosphorus content increased from 0.045% to 0.231%. Increasing the inner coal levels also caused more hematite to be reduced to metallic iron but the oolitic structure of the roasted product was preserved in the presence of high coal loading. The phase of the phosphorus in raw ore was not changed after direct reduction roasting. The effect of coal on the phosphorus content in the H-concentrate arises from changes in the difficulty of mechanically liberating the metallic iron from the phosphorus bearing minerals.     

高磷铁矿碳热还原同步脱磷的实验研究

为探索高磷铁矿的有效利用途径,对高磷鲕状赤铁矿进行碳热还原同步脱磷实验研究,在含碳球团中添加CaO和Na2C O3作为脱磷剂,采用D T A-T G- M S综合热分析、X R D、SE M、E DS等方法分别对高磷鲕状赤铁矿的碳热还原过程以及还原产物进行分析. 结果表明,添加适量的CaO和Na2C O3可以显著提高脱磷率;在1 573 K、Na2C O3添加量为2 %、含碳球团碱度为1 .2的条件下,高磷鲕状赤铁矿能够被快速还原成含磷0 .09 %、含碳4 .6 %的碳饱和铁,脱磷率达到95 %;生铁中碳过饱和后以片状石墨的形态析出,生铁中的磷以夹杂物Ca3（P O4）2和Na2Ca4（P O4）2SiO4的形式存在     

Magnetizing roasting mechanism and effective ore dressing process for oolitic hematite ore

Magnetizing roasting of oolitic hematite ore from western Hubei Province was investigated.The mechanism for reduction roasting of oolitic hematite ore was discussed and analyzed.It is found that flash magnetizing roasting-magnetic separation process is a promising approach for the processing of oolitic hematite ore from western Hubei Province.     

磁化矿石颗粒模型及磁选过程分析

基于磁选过程中颗粒尺寸、磁场强度和磁选精矿品位三者之间的关系,建立磁化矿石颗粒模型,对其进行理论分析与计算,确定最佳磁场强度,并进行磁化矿石的磁选研究。结果表明：在配煤量4%（质量分数）,焙烧温度850℃,焙烧时间60 min,磨矿细度-0.074 mm占60%（质量分数）,磁场强度为40 mT的条件下,得到铁品位57.7%（质量分数）,铁回收率90.3%（质量分数）的铁精矿,较好地实现了铁精矿的富集和回收。     

细粒难选锐钛矿浮选试验研究

对TiO2品位为10.97%的某细粒复杂难选锐钛矿进行浮选试验研究.研究表明,试样磨矿细度为-0.043 mm占85.96%时,以碳酸钠将pH调至8.5,粗选采用羧甲基纤维素和氟硅酸钠为组合抑制剂,精选采用硫酸铝和淀粉为组合抑制剂,用乙酸铅作活化剂,用苄基胂酸和羟肟酸钠作组合捕收剂,经两次粗选、三次精选的浮选工艺,可得到产率为28.51%、TiO2品位为30.91%、回收率为80.32%的锐钛矿精矿,初步实现了细粒难选锐钛矿的选矿富集,为该矿的进一步深入研究及开发奠定了一定的基础,同时为伴生的V、Cr、Co等稀土元素的综合回收利用提供了一定的参考.研究结果表明：①锐钛矿的可浮性与金红石相似,Pb2＋离子同样是锐钛矿浮选的有效活化剂;②对嵌布粒度细、矿物组成复杂的难选矿,药剂的组合使用是使目的矿物以连生体的形式浮选富集的有效手段.     

Effect of Na<Subscript>2</Subscript>CO<Subscript>3</Subscript> and CaCO<Subscript>3</Subscript> on coreduction roasting of blast furnace dust and high-phosphorus oolitic hematite

Iron was recovered from blast furnace dust and high-phosphorus oolitic hematite in the presence of Na₂CO₃ and CaCO₃ additives. The functions of Na₂CO₃ and CaCO₃ during the coreduction roasting process were investigated by XRD and SEM-EDS analyses. Results indicate that these additives not only hinder the reduction of fluorapatite, CaCO₃ also decreases the P content of direct reduced iron (DRI) by increasing the reduction alkalinity. P remains as fluorapatite in the slag, which can be removed by grinding and magnetic separation under optimal conditions. The Na₂CO₃ promotes hematite reduction and improves the iron recovery (ε_Fe) by replacing the FeO from fayalite, which results in quick growth and aggregation of metallic iron and improvement of ε_Fe in DRI. A DRI with 91.88 mass% Fe, and 0.065 mass% P can be achieved at a recovery of 87.86 mass% under the optimal condition.