新形势下氧化铝工艺烧结法改拜耳法的实践突破

本文介绍了我国烧结法制取氧化铝工艺改造成拜耳法的必要性,以及改造方案的选择依据.着重阐述了原料磨,沉降槽,分解槽、赤泥旋流分砂等各环节的改造过程.改造后的精液Al2O3产出率最高达到91.5kg/m3,循环效率达到134.5kg/m3 -调配度,每吨氧化铝降低能耗1.03吨标准煤,年创造经济效益7千万元左右,为我国氧化铝行业探索高效发展提供了有力借鉴.     

锂在氧化铝生产过程中的存在行为

本文对氧化铝生产过程各种物料中锂的含量进行了检测，分别对拜耳法、烧结法和联合法生产氧化铝流程中锂的存在行为、平衡状态进行了分析。氧化铝生产中锂由铝矿石带入，部分锂由氧化铝产品带出，对产品质量有一定影响，生产过程中锂基本处于动态平衡状态，锂对物料中全碱的测定影响可忽略不计。     

Transformation of hematite in diasporic bauxite during reductive Bayer digestion and recovery of iron

The reductive Bayer digestion by using iron powder as reductant is proposed to convert hematite to magnetite and further to dissociate iron minerals from sodium aluminosilicate hydrate (desilication product, DSP) based on the differences of their surface properties. The results show that the differences of surface properties between magnetite and DSP in zeta potential, wettability and solvation trend facilitate magnetite to agglomerate, grow up and thus to dissociate from DSP. The increments of reductant amount and alkali concentration favor the transformation of hematite in digestion with the relative alumina recovery of 98.91%. Processing the resultant red mud can obtain qualified iron concentrate with iron grade of approximate 60% and recovery of about 86% through magnetic separation, resulting in reduction of red mud emission higher than 70%. The results are potential to develop a novel technology for processing high iron diasporic bauxite efficiently and provide references for comprehensive utilization of high iron red mud.     

熟料烧结过程中氧化铁反应行为的热力学分析

通过对Fe2O3与碳酸钠、氧化钙以及硅酸钙反应的热力学分析,明确Fe2O3在铝土矿炉料烧结过程中的热力学反应规律。热力学计算、分析结果表明:Fe2O3在正常烧结温度范围内能与Na2CO3或CaO发生反应,但更易与CaO反应形成2CaO.Fe2O3或CaO.Fe2O3,Fe2O3和Na2O.Fe2O3能使2CaO.SiO2和3CaO.2SiO2转变为CaO.SiO2,CaO.SiO2进一步与Na2O.Al2O3或Na2O.Fe2O3反应生成不溶的三元化合物而造成烧结法生产氧化铝过程中Na2O和Al2O3的损失。4CaO.Al2O3.Fe2O3不能由铁酸钙和铝酸钠相互反应产生,而可能是CaO、Al2O3和Fe2O3三者直接反应的产物,且在烧结条件下Na2O.Fe2O3可分解4CaO.Al2O3.Fe2O3。     

Calcification–Carbonation Method for Cleaner Alumina Production and CO2 Utilization

In this study, a calcification–carbonation method is proposed to change the equilibrium structure of red mud produced from the Bayer process. The thermodynamics of both calcification and carbonation processes has been elucidated. In addition, the non-isothermal kinetics involved in the calcification process and the effects of different parameters on the hydrogarnet synthesis and carbonation decomposition are experimentally investigated using pure reagents. The results indicate that through a two-step carbonation treatment of calcified slag by the new method, the mass ratio of alumina to silica (A/S) of the modified red mud has decreased to 0.44 and the Na₂O content drops to 0.12 wt.% at the carbonation temperature of 120°C under the CO₂ pressure of 1.2 MPa. The newly modified red mud could be directly used in the cement industry.     

山西分公司拜耳法赤泥工程特性及堆存方式的探讨

本文通过对山西分公司拜耳法赤泥工程特性试验的分析．多方位、多角度探索山西分公司拜耳法赤泥的排放和堆存方式，以寻求经济合理可行的排放和堆存方式     

Enhanced conversion mechanism of Al-goethite in gibbsitic bauxite under reductive Bayer digestion process

The conversion mechanism of Al-goethite under the action of different additives (lime or reductant for typical or reductive Bayer digestion) was investigated by thermodynamic calculation, XRD, and SEM?EDS. The results show that the formation of Fe-substituted hydrocalumite is crucial to converting Al-goethite to hematite during Bayer digestion by adding lime. However, the conversion proceeds more easily under the action of reductant due to the rapid formation of magnetite. Additionally, Bayer liquor composition significantly affects the product composition and also the conversion rate of Al-goethite. Compared to typical Bayer digestion with Al-goethite containing gibbsitic bauxite as raw material, the red mud yield of reductive Bayer digestion decreases from 39.02% to 31.19%, and the grade of TFe in red mud increases from 41.66% to 53.80%.     

浅谈氧化铝工业污染防治对策

分析我国氧化铝工艺水平和污染防治现状,提出应根据铝土矿实际情况,优先选择拜耳法和联合法工艺技术,提高工艺技术水平,提高熟料烧成窑处理水平、控制物料堆场的无组织排放,采用节水工艺技术、降低新水单耗,完善废水零排放技案,保证赤泥堆场安全稳定运行,拓宽赤泥综合利用渠道,加强炉窑监控等污染防治对策。     

Research progress on desulfurization technology of high-sulfur bauxite

Bauxite is the main raw material of the alumina industry. However, high-sulfur bauxite constitutes a relatively large proportion of bauxite resource in China. Excessive sulfur impurities in bauxite have significant impact on the Bayer process, such as corrosion of equipment and pipelines, increased consumption of alkali, and difficulties in sedimentation of red mud particles after digestion. As the mainstreams of bauxite desulfurization technologies, the bauxite pre-desulfurization (roasting, electrochemistry, biology, flotation, etc) and Bayer process desulfurization (oxidation and precipitation) need to be fully understood for the further improvement of desulfurization performance. Here, an in-depth review on their mechanisms and advantages/disadvantages is presented.     

The mineralogy of bauxite for producing smelter-grade alumina

Aluminum-producing companies rely on low-cost, high-purity, smelter-grade alumina (aluminum oxide), and alumina production utilizes the bulk of bauxites mined world-wide. The mineralogy of the bauxites has a significant impact on the operation of the Bayer process for alumina production. Typically, the Bayer process produces smelter-grade alumina of 99.5% Al₂O₃, starting from bauxite containing 30% to 60% Al₂O₃. The main objective of the Bayer process is to extract the maximum amount of aluminum from the bauxite at as high an aluminate concentration in solution as possible, while limiting any troublesome side reactions. Only with a better understanding of the chemistry of the mineral species and a strict control of the operating/processing conditions can the Bayer process produce efficiently, a low cost, high-quality alumina with minimum detrimental environmental impact. For more information, contact M. Authier-Martin, Raw Materials R&D, Arvida Research and Development Centre, Alcan International Limited, Jonquiere, Quebec, Canada G7S 4K8; monique.authier@alcan.com.     

赤泥中回收稀土金属的综述

叙述了从赤泥中稀土金属回收的意义以及我国赤泥中稀土元素的赋存状况.介绍了国内外从赤泥中回收稀土元素的工艺,并对其进行了评述.针对我国山西铝厂的赤泥中含钙和钠较高的特点,提出了先焙烧,再用盐酸浸出稀土,然后在浸出液中加碱,得到钪等稀土金属氧化物沉淀,最终分离的新工艺.该工艺能有效分离稀土,易实现工业化生产,废水处理量少,不产生新的污染,符合节能和环保的要求.但是目前还停留在实验室阶段,要实现工业化生产,其经济效益如何有待于进一步的实践证明.     

从赤泥中综合回收有价金属工艺的研究进展

本文对国内外各种氧化铝生产方法所产生的赤泥的物质组成。即化学组成和矿物组成进行了叙述；着重综述了国内外从赤泥中综合回收各种有价金属包括铁、钍、铝、钪和其它稀土元素等的还原炼铁——炉渣浸出工艺、焙烧还原——磁选——浸出工艺、酸浸出——提取工艺及其它生产、研究工艺新进展。并对其进行了评述。     

郑州氧化铝厂赤泥化学和矿物学特征及资源化利用探讨

研究了郑州长城铝业有限公司氧化铝厂所排放的拜耳-烧结联合法赤泥的基本化学和矿物学特征。选取新鲜、五年堆期和十年堆期的赤泥,分析项目包括pH、EC、水溶性和交换性盐基离子、X射线衍射矿物分析等。此外,还采用为期两年的慢速接力滴定法对这三种不同堆期赤泥的酸中和容量进行测定。选取酸中和能力最强的新鲜赤泥作改良剂,检测其作为改良剂对消除酸性矿山土壤酸性、降低土壤重金属活性和促进植物生长的效果。     

初探混联法生产氧化铝的工艺优化

在目前的生产条件下。通过大量的混联法物料衡算，定量地研究了供矿铝硅比、熟料铝硅比和拜年法赤泥铝硅比对混联法的制造成本、能耗和拜年法与烧结法的生产比例的影响规律，提出我国混联法生产进一步优化的方向和途径。并开发了研究和评价的计算软件。为混联法的生产和设计的进一步优化奠定基础。     

浅析石灰添加量对拜耳法溶出赤泥N/S的影响

拜耳法生产为降低碱耗需要添加一定石灰,本文针对石灰添加量对溶出赤泥N/S的影响进行了简要分析,探讨了适合山西分公司中品位矿石的拜耳法溶出条件。     

Reduction of Red Mud Discharge by Reductive Bayer Digestion: A Comparative Study and Industrial Validation

JOM - A novel design incorporating both reductive Bayer digestion and iron recovery into diasporic bauxite processing is proposed to remarkably reduce red mud discharge. This paper presents a...     

影响拜耳法赤泥N/S的因素分析

对影响溶出赤泥N/S的主要因素进行了详细地分析,并结合山西分公司的实际情况,提出了降低赤泥N/S的措施,对实际生产有着一定的指导意义.     

Recovery of scandium from bauxite residue——red mud:a review

Red mud is a slimy caustic residue generated from alumina production. Taking into account the relatively considerable content and availability of scandium, red mud can be viewed as an important and promising scandium resource rather than a solid waste. This paper is primarily to review the investigations of scandium recovery from red mud based on the most widely used hydrometallurgical processes including acid leaching, solvent extraction and ion exchange adsorption. It is thought that recovery of scandium from red mud should be considered as a direct objective rather than a by-product in the development of overall flowsheet. In order to achieve environmentally-friendly processes with high scandium recovery and low cost, more attention is required to be paid to optimizing the selective leaching of scandium to decrease mineral acid consumption and alleviate pollution, and developing new solvent extraction systems and novel ion exchange adsorption materials with high selectivity and recognition for scandium.     

高A/S低[F/A]熟料添加矿化剂降低烧成温度试验研究

针对熟料氧化铝含量提高、氧化铁含量降低以后,烧成温度升高这一难题,探索采用添加矿化剂CaF2的方法降低烧成温度的可行性.进行了不同添加量的烧结试验,对高铝熟料的烧结性能有了更深刻的认识,并在试验室条件下进行了溶出及赤泥沉降性能试验.为氧化铝含量大干40%的熟料的烧结找到了一种降温用矿化剂.