铝土矿高温溶出过程的性能研究

评述在高压溶出铝土矿过程中,加入石灰等添加剂可以改善氧化铝溶出的工艺过程,同时论述石灰添加量、溶出时间、溶出温度对氧化铝溶出率的影响,并对其作用机理进行了分析.     

高硫铝土矿溶出过程中脱硫研究

研究了高硫型高品位铝土矿溶出过程的脱硫效果,考察了石灰添加量、溶出温度、苛性碱浓度和溶出时间对铝土矿中脱硫效果的影响。结果表明,在溶出高硫铝土矿时,脱硫效果最佳条件是:石灰添加量10%,温度245℃,脱硫时间70 min,碱液浓度240 g/L。此时,硫的溶出率仅为31.3%,同时又能保证氧化铝溶出率不低于81%。     

低温磁化焙烧对高铁铝土矿溶出及磁选性能的影响

为实现高铁铝土矿铝铁元素的高效利用，采用“低温磁化焙烧-拜耳溶出-赤泥磁选”的方式处理高铁铝土矿，考察了焙烧温度、H₂浓度及通入时间对高铁铝土矿溶出及磁选性能的影响。结果表明，焙烧过程中一水硬铝石脱水转变为过渡态Al₂O₃，矿物发生热破裂现象，比表面积增大，氧化铝溶出活性增加，在焙烧条件为焙烧温度530℃、H₂浓度20vol%、H₂通入时间5 min时，氧化铝相对溶出率可达97.65%。磁化焙烧过程中，针铁矿转变为赤铁矿，再由赤铁矿转变为磁铁矿，通过溶出解除了铝铁元素之间的嵌布关系，对焙烧矿的赤泥进行磁选，其铁精矿品位达62.05wt%，铁回收率为86.36%。     

高铁三水铝石型铝土矿在铝酸钠溶液中的溶出过程

在对某高铁三水铝石型铝土矿物相分析基础上,研究了其在不加钙的铝酸钠溶液中的溶出行为,考察了溶出液碱浓度、溶出温度和溶出时间对氧化铝溶出率的影响.结果表明,矿中Gibbsite形态的铝约占总铝量的70%,且嵌布于赤铁矿中;优化的溶出条件为,分子比3.0的铝酸钠溶液Na2O浓度为150 g/L、温度100℃、时间15 min,此时原矿中Al2O3溶出率达72%.该矿在低温低碱条件下的溶出过程受内扩散控制,计算的表观活化能为61.78 kJ/mol,溶出速率控制模式与表观活化能理论值不同可能与扩散形式相关.     

贵州某高硫铝土矿氧化铝溶出研究

对贵州某矿区高硫铝土矿的化学成分及物相进行了分析,了解矿物存在形态,采用中国铝业贵州分公司生产中的种分母液和蒸发母液进行适当配制后作为溶出用碱液,利用正交实验研究方法,考察了石灰添加量、苛性碱浓度、温度、时间对氧化铝溶出率的影响。实验结果表明,该矿区矿石氧化铝溶出率不高,在较佳溶出条件:温度260℃,时间90 min,石灰添加量为6%,碱浓度235 g/L时,氧化铝相对溶出率为95.21%。     

粒状氢氧化铝在工业领域的应用

氢氧化铝[Al(OH)3],工业上称氧化铝水合物,它是氧化铝生产中,从铝土矿提炼氧化铝的中间产品,目前,世界上氧化铝的生产方法主要有拜耳法和烧结法,拜耳江用于处理低硅高位铝土矿,它的生产过程包括,原矿浆制备,高压溶出,压煮矿浆的稀释及赤泥分离和洗涤,晶种分解,氢氧化铝的分洗涤和烘干等,烧结法用于处理高硅低品位铝土矿,它的生产过程有：生料浆制备,熟料烧结和溶出,赤泥分离洗涤,粗液脱硅,碳酸化分解,氢氧化铝分离洗涤和烘干,我国的铝土矿主要为一水硬铝石型,多采用烧结法生产,烧结法生产出的氢氧化铝,具有白度高的优点.     

拜耳法中石灰添加量对氧化铝溶出率的影响

在拜耳法高压溶出过程中，添加石灰可以改善氧化铝溶出的工艺过程，石灰添加量对氧化铝溶出率影响极大；最佳的石灰添加量可以获得较好的溶出效果。     

二段酸溶法制取碱式氯化铝

本文研究盐酸二段溶出低品位铝土矿制取碱式氯化铝,并与焙烧法、加压法对比,认为加入少量引发剂能显著提高氧化铝溶出率,制得产品主要是多核羟基铝的聚合体。     

高硫铝土矿的焙烧预处理

采用回转窑对我国高硫铝土矿进行焙烧预处理,考察了焙烧温度、焙烧时间对矿物中硫含量及氧化铝溶出性能的影响,利用SEM和XRD技术对焙烧矿的微观形貌、晶型结构变化进行了分析,并对高硫矿脱硫机理和焙烧机理作了探讨. 结果表明,焙烧脱硫处理高硫型铝土矿是可行的,焙烧温度为750℃、焙烧时间为60 min时,焙烧矿中硫含量低于0.7%,达到我国 氧化铝生产的工业要求;焙烧矿在溶出温度220℃、溶出时间60 min的条件下,氧化铝溶出率达到97%以上.     

高硫高硅铝土矿焙烧–溶出性能研究

采用悬浮焙烧对高硫高硅铝土矿进行处理,考察了不同焙烧温度对矿石中硫含量的影响,通过X射线衍射和扫描电子显微镜分析了不同温度条件下焙烧对铝土矿中物相变化及微观形貌的影响,研究了焙烧温度对矿石中氧化铝溶出性能的影响。结果表明,悬浮焙烧温度600℃及以上时,能够使铝土矿硫化型硫含量降至0.2wt%以下。焙烧使铝土矿中高岭石相发生分解生成非晶态的偏高岭石,同时破坏矿颗粒致密结构,出现晶粒细化,但温度过高(650℃)会出现局部烧结现象。焙烧使一水硬铝石晶体破坏而活化,600℃时晶体破坏最完全,使600℃焙烧矿在相同溶出条件下溶出效果较原矿及其他焙烧矿优势明显,在溶出温度270℃、苛碱浓度245 g/L、石灰添加量14wt%的条件下,相对溶出率能达96%以上。     

Reaction behavior of quartz in gibbsite-boehmite bauxite in Bayer digestion and its effect on caustic consumption and alumina recovery

A high content of quartz is usually present in Australian gibbsite-boehmite bauxite. The reaction between quartz and sodium aluminate solution at high temperatures in the Bayer process can lead to loss of alumina and sodium oxide. Therefore, to improve alumina recovery, the reaction of quartz needs to be avoided. The digestion behavior of Australian gibbsite-boehmite bauxite and pure quartz in the Bayer process at 230–250 °C was systematically studied in this paper. The mineral composition and morphology of the reaction products were characterized and the kinetics of the quartz dissolution process was studied in detail. It was shown that boehmite in gibbsite-boehmite bauxite can be completely digested at high temperature (250 °C) with a short digestion time (5 min). A short digestion time results in a low reaction rate of quartz in bauxite, and is ideal for alumina recovery at high temperatures. The quartz reaction rate rapidly increases with longer digestion times. The apparent activation energy of the dissolution of quartz in bauxite in the caustic solution is 151.9 kJ mol^?1, and the rate-controlling step of this reaction process is the interfacial chemical reaction. By controlling the particle size of bauxite, the digestion temperature, and the digestion time, the reaction rate of quartz in bauxite can be inhibited, which is beneficial for improving alumina recovery and reducing caustic consumption. Therefore, based on the above theoretical research, a process for digesting gibbsite-boehmite bauxite is proposed using high digestion temperature (250 °C), short digestion time (5 min) and large mineral size. An economic benefit of about US$101.9 million for a refinery with the annual output of 2 million tons of alumina can be created by the proposed process.     

Effect of Bauxite Aggregate on Properties of Al_2O_3-SiC-C Iron Trough Castables

Al2O3- SiC- C iron trough castables were prepared using high alumina bauxite clinker GL-90( 1 mm) or homogenized bauxite GL-88 to replace the traditional brown corundum aggregates( 1 mm) to reduce the cost of iron trough castables. Effects of the two bauxite aggregates on properties of iron trough castables were investigated. The results show that the two kinds of bauxite affect flowability,bulk density,strength and slag corrosion resistance of trough castables differently. Compared with homogenized bauxite,high alumina bauxite clinker is more suitable to substitute brown corundum. The castables prepared from the bauxite clinker have similar performances with those prepared from brown corundum,especially used in medium or small blast furnaces with weak thermal impact and lower temperature hot metal.However,in large blast furnaces with severe thermal impact and high temperature hot metal,the performances of the two castables are significantly different. So it is suggested to use the brown corundum based castables in the front gyral zone of the slag skimmer.     

Effect of Bauxite Aggregate on Properties of AI203-SiC-C lron Trough Castables

A1203-SiC-C iron trough castables were prepared using high alumina bauxite clinker GL-90 （ 〉 1 mm ） or homogenized bauxite GL-88 to replace the traditional brown corundum aggregates （ 〉 1 mm ） to reduce the cost of iron trough castables. Effects of the two bauxite aggregates on properties of iron trough eastables were investigated. The results show that the two kinds of bauxite affect flowability, bulk density, strength and slag corrosion resistance of trough castables differently. Compared with homogenized bauxite, high alumina bauxite clinker is more suitable to substitute brown corundum. The castables prepared from the bauxite clinker have similar performances with those prepared from brown corundum, especially used in medium or small blast furnaces with weak thermal impact and lower temperature hot metal. However, in large blast furnaces with severe thermal impact and high temperature hot metal, the performances of the two castables are significantly different. So it is suggested to use the brown corundum based castables in the front gyral zone of the slag skimmer.     

铝氧生产非碱法工艺的实验研究

为加深我国低品位高硅铝钒土、以及煤系伴生矿（高岭土、耐火粘土等）的综合利用层次，作者进行了铝氧生产非减法工艺的系统研究本文报导了低品位高硅铝钒土生产铝氧的H＋法和铵盐法的实验研究．实验考察了温度、反应时间及反应物配比对溶出反应的影响，获得了溶出反应的工艺条件；对铝盐的提纯和解高，也进行了成功的工艺实验．实验结果表明，H＋法和铵盐法工艺，可以生产出合格的氢氧化铝和氧化铝产品．     

粉煤灰提取氧化铝的综合利用

从粉煤灰对环境的危害性和中国铝土矿资源现状两方面论述了粉煤灰提取氧化铝的必要性。介绍了用碱法、酸法、酸碱联合法和一步酸溶法从粉煤灰中提取氧化铝的工艺技术及最新研究进展,结果表明了"一步酸溶法"提取氧化铝的工艺流程短、原料消耗低、氧化铝生产成本低,并在生产过程中无二次污染物产生,该工艺流程更适用于从高铝粉煤灰中提取氧化铝。最后总结了目前粉煤灰的应用情况,倡导加大粉煤灰综合利用的研究力度。     

贵州中低品位铝土矿综合利用分析

简要介绍了中国铝土矿资源的整体分布情况,较为详细地分析了贵州修文中低品位铝土矿的化学成分特点、矿物成分特点及XRD特征,综合阐述了中低品位铝土矿在生产氧化铝、耐火材料、化学制品方面以及其他方面的应用情况。认为贵州铝土矿资源丰富,但属于高铝高硅型,且铝硅比较低,除了少数可以用拜耳法来生产氧化铝外,大部分铝土矿属于中低品位铝土矿,在生产氧化铝方面往往采用联合法来处理。对于中低品位铝土矿,除了用于生产氧化铝外,在耐火材料、陶瓷及聚合物等方面的应用也在日渐发展,实现了铝土矿的综合利用。     

Enrichment of iron from bauxite waste in chemical looping combustion

This work reports a method and findings related to the enrichment of iron from bauxite waste (red mud) using chemical looping combustion (CLC). According to the results from X-ray Diffraction, X-ray Fluorescence, and scanning electron microscope–energy-dispersive X-ray spectroscopy, uniformly distributed iron in the red mud particles migrated outward to the surface during the 148 redox cycles in a bubbling fluidized bed reactor, in which the size-reduced iron-oxide particles due to attrition are concentrated in filters. The concentrations of iron oxide in raw particles and attrition fines are 43 wt.% and 83–87 wt.%, respectively. Since the attrition in CLC is inevitable, this recycled iron oxide can be a valuable by-product to compensate for the cost of CLC, whereas the bed materials continue to participate in the CLC process. Moreover, the abundant bauxite waste can be processed in an eco-friendly manner for integrated power generation, carbon capture, and iron recovery by the proposed strategy in this work.     

粉煤灰回收氧化铝工艺研究进展

粉煤灰是火力发电行业煤炭燃烧工业的副产品,是中国固体废弃物污染的主要来源。粉煤灰富含氧化铝,所以又是潜在的铝土矿的替代品。从粉煤灰中提取氧化铝不仅可以减少粉煤灰对环境的污染,而且能缓解中国铝土资源短缺的问题。对粉煤灰性质、危害、粉煤灰利用现状以及中国铝土资源现状做了分析,论证了粉煤灰提取氧化铝的必要性;详细介绍了石灰石烧结法、硫酸铵烧结法和一步酸溶法的工艺路线、建设生产情况及各工艺的优缺点,为粉煤灰提取氧化铝的发展提出建议,并呼吁加强粉煤灰提取铝工艺方法的研究力度。     

1,10-二氮杂菲光度法测定矾土中游离铁

介绍了1,10-二氮杂菲光度法测定矾土中游离铁的方法。通过实验确定了溶样酸的浓度、加热煮沸时间、称样量等分析条件。矿样基体中添加相应的铁量,回收率在90%～102%。本方法填补了矾土中游离铁检测的空白。     

铁相组分对铁相和高铁低钙水泥熟料水化性能及抗侵蚀性能影响

随着国家海洋战略的提出,大量水泥基材料被应用到海洋工程建筑中,海洋环境对水泥基材料的侵蚀破坏也愈发受到人们的广泛关注。研究表明,水泥中的铁相具有较好的抗侵蚀性能,而铁相中Al₂O₃和Fe₂O₃的摩尔比(Al/Fe,下同)是影响铁相抗侵蚀性能的主要因素。本文设计并烧成了两种铁相单矿C₄AF和C₆A₂F(Al/Fe分别为1和2),以及铁相为C₄AF或C₆A₂F的高铁低钙硅酸盐水泥熟料(铁相质量分数均为20%)。通过对铁相单矿C₄AF和C₆A₂F,以及高铁低钙水泥熟料进行X射线衍射、水化热、抗压强度、抗硫酸盐侵蚀能力和固化氯离子能力等测试,探究Al/Fe对铁相单矿和高铁低钙水泥熟料各项性能的影响。结果表明,随着Al/Fe增大,铁相晶面间距变小,氯离子固化能力增强,而抗硫酸盐侵蚀能力有所下降。同时,熟料中铁相含量提高促进了C₃S的水化,且Al/Fe高的熟料促进效果更加明显。铁相的Al/Fe提高,水泥熟料的氯离子固化能力增强,而抗硫酸盐侵蚀性能下降则较小。