Effect of strong acids on red mud structural and fluoride adsorption properties. Red mud is the major waste material produced during alumina production. Methods for alkaline recovery of aluminum from bauxite. The chemical composition of the red mud samples expressed as distribution of oxides. Demonstrated the red mud compositions and its disposal and environmental. This applies not least in the manufacturing industries and one example from the global aluminium sector is the issue of bauxite residue otherwise termed red mud. The xrd pattern for the bauxite, red mud and clay samples are shown figure5 and supported with xrf analyses in table2. Study of red mud as an alternative building material for.
Jul 08, 2003 red mud is a byproduct of bauxite processing via the bayer process. Basics properties like specific gravity, particle size distribution, atter bergs limit, omc. Although red mud and bauxite residue are often used as synonyms, the contributing editor for this article was dimitrios panias. It is a mixture of compounds originally present in the parent mineral, bauxite, and of compounds formed or introduced during the bayer cycle. Red mud project site dedicated on the valorisation and. Its composition depends upon its parent material from which it is produced liu and wu, 2012. Researchers from csiros mineral resources flagship have developed a process that lowers the cost of refining bauxite aluminium ore to alumina aluminium oxide by treating the waste product generatedred mudto recover a costly ingredient, caustic soda. Composition of bauxite and the generated red mud compound as shown in table. The red mud studied in this work was supplied by eurallumina porto vesme, cagliari, italy as a mixture containing about 60% of solids, obtained immediately after alumina recovery from the digestion process.
According to the grade of the bauxite ore, 23 tonnes of ore yield one tonne of alumina and about one tonne of red mud dry weight. Bauxite tailings, also known as bauxite residue, red mud, red sludge, or alumina refinery residues, is a highly alkaline waste product composed mainly of iron oxide that is generated in the industrial production of alumina. China is the largest producer of aluminum in the world with a. Described herein is a process that converts the red mud into mineral products that can be used for commercial applications. Making the most of red mud february 24, 2014 issue vol.
Bauxite is a sedimentary rock with a relatively high aluminium content. Red mud rm is a byproduct of extracting of alumina from bauxite. The chemical and mineralogical composition of red mud depends largely on the nature of bauxite ore and the extraction process. Bauxite does not make aesthetic or interesting specimens as far as collectors are concerned.
The production rates of red mud depend on the origin of the bauxite. Decreasing yield and alumina content of red mud by. Known formally as bauxite residue, red mud is the noxious byproduct of the bayer process for extracting aluminum from bauxite ore. This is achieved using large clarification vessels mud thickeners, which allow the undissolved bauxite solids to settle out. The bayer process uses caustic soda, high pressure, and high temperature to leach alumina from ferruginous residue slurry bauxite residue or red mud. Physical and chemical properties of sintering red mud. It is the worlds main source of aluminium and gallium. Typical chemical composition and metal content of bayer process red mud are. It is a mixture of hydrous aluminum oxides, aluminum hydroxides, clay minerals, and insoluble materials such as quartz, hematite, magnetite, siderite, and goethite.
As the temperature and pressure increases, the solubility of red mud decreases with sodium hydroxide nie et al. Bauxite potential of guinea whatever concepts and definitions used, it appears from all studies that guinea is the country the most endowed with bauxite in the world. Wong jwc, ho ge 1993 use of waste gypsum in the revegetation on red mud. Physicomechanical properties of bauxite residueclay bricks. Novel uses of red mud in textile wastewater treatment, dyeing, and concrete production. Johannes vind goes in search of the sources of red mud. Production figures on bauxite from victoria in australia are available at the national resources and environment website under minerals and petroleum. Characterization and applications of red mud from bauxite.
Red mud is a waste material derived as residual from the bayer process by the caustic digestion of crushed bauxite at elevated temperature. Preparation of special cements from red mud journal article. Thus there is wide variation in chemistry of red mud, as follows. Red mud is a solid waste residue of the digestion of bauxite ores with caustic soda for alumina production. Red mud, or bauxite residue, is the largest environmental concern of alumina refineries, mainly because of the size of this waste stream and its caustic characteristics. Red mud is the waste product that is produced in the digestion of bauxite with sodium hydroxide. The utilization and value addition of iron in redmud is a critical measure for economically valorizing the waste and it eases the process of extracting. It fulfills the long absent need for a comprehensive description of jamaican bauxite both as a reference for their geology and geochemistry, a. The effects of bauxitealumina waste on the composition of. To force reaction 1, elevated or even high temperatures are necessary depending on the mineralogy of the processed bauxite. Ncu scientist points to recognised solution for alumina dumps. Over the period 2003 to 2006 the bauxite feed to the kirkvine refinery has undergone a dramatic change in composition with severe impact on plant performance. The utilization and value addition of iron in red mud is a critical measure for economically valorizing the waste and it eases the process of extracting.
Successes and challenges in the bauxite residue valorization. Wong jwc, ho ge 1993 use of waste gypsum in the revegetation on red mud depositsa greenhouse study. It is the insoluble product after bauxite digestion with sodium hydroxide at elevated temperature and pressure. Iron is a major constituent in most of the worlds reserves of bauxite residue 3 billion tons. Red mud bauxite residue is a byproduct generated during the bayers processing of bauxite. Bauxite is not a mineral, but rather a group of aluminum oxide s. According to the grade of raw material bauxite and the production process of alumina, red mud can be divided into bayer red mud and sintering red mud 1,2. The term is generally used to describe the economically important mixture of these minerals, which form a mass of the individually classified members of gibbsite, boehmite, and diaspore. As to the recovery of valuable metals from ironrich bauxite and red mud, there are a lot. Analysis on physical and mechanical properties of red mud. It fulfills the long absent need for a comprehensive description of jamaican bauxite both as a. Red mud is a product of the bayer process during the production of alumina hairi et al.
The waste slurry is called red mud, while the solid fraction is called bauxite residue. Recovery of rare earths and other valuable metals from. Bauxite residue red mud is a hazardous waste generated from alumina refining industries. Its disposal remains a worldwide issue in terms of environmental concerns. Red mud is the caustic byproduct stream from alumina production via the bayer process, often colloquially referred to as red mud or bauxite residue or bayer process tailings 1, 2. Composition and properties of red mud in the world have been presented by many researchers in their publications.
Pdf the composition, recycling and utilisation of bayer red mud. Chemistry of trace and heavy metals in bauxite residues red. This paper describes the characteristic properties of red mud and possible use as a. Red mud is a concentration of many elements, aluminium mainly. This material was heated for 2 h at 120c, affording a reddishorange powder. It has high calcium and sodium hydroxide content with a complex chemical composition, and accordingly is very caustic and a potential source of pollution. Advantages and disadvantages exist in different recovering processes. Iron recovery from bauxite tailings red mud by thermal reduction with blast. Bauxite processing waste is a combination of the unwanted components of the bauxite ore once aluminium has been extracted from it mainly oxides of iron, silicon, titanium, manganese and some aluminium oxide red mud and waste chemicals used in. Bauxite residue generation balance between aluminous content of the bauxite, type of aluminium containing compound, local energy cost, transport cost, silica content reactive more important than crystalline when plants located very distant from the bauxite source, they tend to use high alumina bauxite and high. Methods for alkaline recovery of aluminum from bauxite residue. Lancashire, bauxite and aluminium production, education in chemistry, may 1982, pps 6264. This article specifically covers the alkaline waste generated when operating the bayer process. Current iron recovery techniques using red mud are depicted.
The aluminum mineral bauxite information and pictures. Zerowaste valorisation of bauxite residue red mud summer school 2931. These bauxite solids are then passed through a countercurrent washing train mud washers using water to recover as much of the caustic as possible to enable it to be returned to the recycled caustic liquor. The effects of composition proportions of lime, red mud, fly ash, bauxite and gypsum, firing temperature and duration on the properties of cements produced were studied in detail. The accumulation of redmud or bauxite residue in the world is 30 billion metric tons. Composition of bauxite and the generated red mud sl. Dealing with red mud by product of the bayer process for. A major challenge going forward is to reconcile mans activities on earth with the key pillars of environmental stewardship, sustainability and safeguarding life forms. Red mud project site dedicated on the valorisation and best. The composition and properties of rm depend on the bauxite ore sources and. When designing an alumina plant, factors other than the type of bauxite ore to be used as feed material and the form of alumina to be produced have to be taken into consideration.
Red mud in an liquid state causes harmful effects to human skin. Fe 2 o 3 2060 wt%, al 2 o 3 1030 wt%, sio 2 0220 wt%, tio 2 028 wt%, na 2 o 210 wt% and cao 28 wt%. Summer school zerowaste valorisation of bauxite residue red mud summer school 2931 august 2016, leuven, belgium. The actual composition of red mud depends on the type of bauxite, the mining location and the process parameters of the bayer process40. Many valuable components such as rareearth elements, al, and fe, in rm are difficult to be. Aluminum mining leaves behind a staggering 120 million metric.
Pdf red mud or bauxite residue is a solid waste generated from. Particle size distribution in red mud showed a fine physical texture of solid sludge. Mineral compositionof the red mud depends on the mineral composition of the source material bauxite. Bauxite is a multiphase ore that may contain, according to some referen. Bauxite industry in guinea and value opportunities of the. Geotechnical characterization of bauxite residue red mud. Bauxite potential of guinea whatever concepts and definitions used, it appears from all studies that guinea. It is important to differentiate between the alkaline waste generated in the bayer process and the tailings generated during the mining of bauxite.
Review the composition, recycling and utilisation of bayer red mud. Redmud bauxite residue is a byproduct generated during the bayers processing of bauxite. Bauxite residue generation balance between aluminous content of the bauxite, type of aluminium containing compound, local energy cost, transport cost, silica content reactive more important than crystalline when plants located very distant from the bauxite source, they tend to. Bayer process is a process of extracting the alumina from the bauxite invented by the austrian chemist bayer between 1889 and 1892, and its tailing is bayer red. Bauxite tailings, also known as bauxite residue, red mud, red sludge, or alumina refinery residues arr, is a highly alkaline waste product composed mainly of iron oxide that is generated in the industrial production of alumina aluminium oxide, the principal raw material used in the manufacture of aluminium metal and also widely used in the. Red mud is the residue from the alkaline leaching of bauxite ore, which is the. Residues from different bauxite have a wide range of composition. About 90% of raw bauxite ore goes into the waste as alkaline red mud slurry during processing 3 as for every ton. European training network for zerowaste valorisation of bauxite residue redmud blog. Red mud is produced during the bayer process for alumina production.
Fabrication and characterisation of ghanaian bauxite red mud. Bauxite consists mostly of the aluminium minerals gibbsite aloh 3, boehmite. Red mud tanrai alumina processing plant contains a big content of oxides, such as. Bauxite residue is the ironoxide rich mine waste from the processing of bauxite ore for the extraction of alumina through the bayer process. Red mud project site dedicated on the valorisation and best practices on bauxite residue. Economic and environmental friendly integrated usage of red mud is promising. Bauxite processing waste is a combination of the unwanted components of the bauxite ore once aluminium has been extracted from it mainly oxides of iron, silicon, titanium, manganese and some aluminium oxide red mud and waste chemicals used in the extraction process mainly sodium hydroxide. Sodalite has the composition n 2, but less hydrated compounds may exist as.
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