Red mud is a byproduct of aluminum production, in which alumina is extracted from bauxite ore via the bayer process. M e t a l l u r g i e p r o z e s s t e c h n i k recycling results carbothermic reduction and leaching main components in wt. The major chemical composition of red mud for selected countries over the world is presented in table 2. It must be removed from the pregnant caustic liquor prior to precipitation or. Dealing with red mud by product of the bayer process. Once aluminum is extracted from bauxite, the remains are a porous matrix of metalsa mineral skeleton, iannicelli explains. Disposal of the red mud is a major problem due to the large amounts that are created1in seydisehir, turkey, for example, more than 3 million tons of red mud have accumulated over the past few decades. Bayer method dissolution of pulp from the red mud is red mud and the formation of sodium aluminates solution suspension. Fe 2 o 3, al 2 o 3, sio 2, tio 2, nao, k 2 o, cao and. Red mud rm is a solid waste product obtained from aluminum industries via bayers process. This can be explained by temperature having a significant effect on the dissolution of alumina and therefore increasing the diffusion of digestion liquor on bauxite.
The jbi labs analyses a range of sampletypes for chemical and mineralogical composition for a fee eg. Up to now 2006 red mud, is discharged through a pipe line at the sea of antikyra bay. Red mud is the solid waste residue of the digestion of bauxite ores with caustic soda for alumina al2o3 production. The main problem with the mud is its strongly alkaline nature, ranging from ph 10 to, and it was this that did the damage in the hungarian spill.
Tga and dtg were shown to detect and estimate reasonably low level gibbsite and goethite in in byproduct red mud samples. The inventors propose a process that produces a rm cake low in caustic and alumina concentration permitting environmentally friendly disposal. Analysis of alumina red mud wet flue gas desulfurization. Red mud is a hazardous waste generated from alumina refining industries. Pdf the composition, recycling and utilisation of bayer red mud. Bauxite, the most important ore of aluminium, contains only 3060% aluminium oxide al 2 o 3, the rest being a mixture of silica, various iron oxides, and titanium dioxide. Making the most of red mud february 24, 2014 issue vol. First, brief description of red mud each ton of alumina produced about 1. It is generated from the refining of bauxite for alumina production al2o3 by the bayer process. Approximately 3540% of the processed bauxite ore goes into the waste as alkaline red mud slurry which consists of 1540% solids and 0. The performance of red mudadsorbents in the removal of inorganic anions, heavy metals and organic compounds from wastewaters, and gaseous effluents is also discussed.
Known formally as bauxite residue, red mud is the noxious byproduct of the bayer process for extracting aluminum from bauxite ore. As the temperature and pressure increases, the solubility of red mud decreases with sodium hydroxide nie et al. Red mud, a residue of the alumina production industry which is actually a solid waste, has. Pdf red mud or bauxite residue is a solid waste generated from the. The effects of na 2 o c concentration, reaction temperature, reaction time, liquidsolid ratio on the leaching rate of alumina were investigated and. Thus, disposal of red mud is an environmental concern and it should be recycled in an effective way. Its composition depends upon its parent material from which it is produced liu and wu, 2012. 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. For the comprehensive utilization of waste, the mineral component, chemical composition, grain size and microstructure of alumina red mud from henan branch of china aluminum co.
The major chemical composition of ironrich red mud generated in alumina plants in. Several studies explored the use of red mud as a component in clay bricks bricks made of fly ash and red mud. The composition of red mud varies depending on the composition of the orig. Red mud was reduced in a tube furnace in an atmosphere of co, co. Tga can do similarly for boehmite content of red muds byproduct of the bayer process. Dealing with red mud by product of the bayer process for. A new project, involving high pressure filtering and dry disposal and reuse of red mud, is under implementation.
R recovered from waste of silica alumina refractory bricks. The situation concerning the disposal method is changing. It is important to differentiate between the alkaline waste generated in the bayer process and the tailings generated during the mining of bauxite. The output, composition and characteristics of red mud vary with the type of bauxite and the. Approximately, 3540% of the processed bauxite ore goes into the waste as alkaline red mud slurry which consists of 1540% solids, and 1. Methods for utilization of red mud and its management.
Mar 16, 2016 this study investigates the level of technological enhancement of normally occurring radioactive materials tenorm in the red mud waste due to the production of alumina in jamaica. Red mud is the finegrained residue left after alumina extracted from the bauxite ore. Bauxite is a multiphase ore that may contain, according to some referen. Both alumina recovery and na 2 osio 2 ratio of red mud increase with increase in temperature in case of no lime usage. The alumina process used today is essentially the one invented by karl bayer in 1887. The composition of red mud is shown in the table below. Red mud minimisation and management for the alumina industry by the carbonation method a thesis submitted in fulfilment of the requirement for the degree of doctor of philosophy environmental engineering by cuong phuoc tran february 2016 school of chemical engineering faculty of engineering, computer and mathematical sciences. The authors present aspects related to red mud composition and the types of treatments applied to red mud to enhance its adsorption or catalytic performances.
The bayer process, which refines bauxite to produce alumina aluminum oxide, generates a significant waste stream. Red mud disposal still remains a major environmental issue in alumina production and the world wide aluminium industry has been constantly trying to find a viable and permanent solution to dispose and reuse the red mud produced enormously during alumina extraction. Red mud is a byproduct produced in the process of extraction of alumina from. The refinery adopted an innovative and investmentfree mud preparation technology, where the material undergoes unaided separation and drying at the bauxite residue disposal area.
For each part of alumina produced, about one part of red mud is generally superfluous as a waste. The composition of the red mud is mostly oxides of iron, titanium, soda alumina silicate compounds, unreacted quartz, and other insolubles in the bauxite. Synthesis and properties of red mudbased nanoferrite clinker. Pdf a study on the characterization of red mud researchgate. Red mud rm is a solid caustic waste or a byproduct formed after the digestion of bauxite ore with sodium hydroxide in a solution of concentrated naoh at 150230c under pressure in bayers process for the extraction of alumina kurniawan et al. Bauxite tailings, also known as bauxite residue, red mud, red sludge, or alumina refinery. Chemical analysis shows that red mud contains silicon, aluminum, iron, calcium, titanium, sodium as well as an array of minor elements namely k, cr, v, ba, cu, mn, pb, zn, p, f, s. On occasion, red mud discharges have created environmental calamities, such as the ajka sludge spill in western hungary during 2010. Survey of bauxite resources, alumina industry and the.
Red mud contains high quantities of alkaligenerating minerals and metal ions, which can cause significant environmental damage. The red mud is a residue of the industry of aluminum mining. Physical and chemical properties of sintering red mud and. More than 120 million tons of rm is generated annually all over the world and about 4 million tons is in india. This article specifically covers the alkaline waste. 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 study of the red mud specimen from an alumina production site included tgadtg and dsc analyses. Applying red mud as construction materials like cement, soil ameliorant applications face the problem of na, cr, as leaching into the environment. 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 generated red mud to recover a costly ingredient, caustic soda. Mineral compositionof the red mud depends on the mineral composition of the source material bauxite.
Two step stir casting process is used to fabricate the composites by varying volume fractions of red mud 5%, 10% and 15% volume fractions. In india, major producer vedanta aluminium ltd has commissioned a red mud powder processing unit at its lanjigarh refinery in odisha, probably the first of its kind in the alumina industry addressing major environmental hazards. It is the insoluble product after bauxite digestion with sodium hydroxide at elevated temperature and pressure. Red muds may also contain trace amounts of elements such as barium, boron, cadmium, chromium, cobalt, gallium, vanadium, scandium, and lead, as well as radionuclides. Red mud rm is a solid waste byproduced formed after alumina production from bauxite following the bayer process. Composition and refractory properties of mixtures of moroccan. In other words, for each ton of alumina or half ton of aluminum, approximately one ton of red mud based on dry weight is produced. The composition and properties of rm depend on the bauxite ore sources and. Red mud is the major waste material produced during alumina production.
Wanchao liu zhengzhou research institute of chalco. How aluminum is made material, manufacture, making, used. A method for producing bricks from red mud containing free alkali wherein no softening occurs during firing of the bricks, comprising mixing red mud having a residual water content of 15 to 35 weight%, based on the weight of dry red mud, with a clay which can chemically bond with and vitrify the free alkali in the red mud to provide a resulting mixture containing 50 to 92 weight. There are two methods of red mud disposal using seawaterdumping red mud directly into the sea or treating red mud at alumina plant bauxite residue sites near the sea. New technologies to rehabilitate dams into useful land. The unique project to produce red mud powder has been commissioned in a fully mechanised and automated plant. Polyacrylamide used as setting flocculants for the red mud. The refinery adopted an innovative and investmentfree mud preparation technology, where the material undergoes unaided separation and. However, the hightemperature reduction, smelting and alkaline leaching process is a feasible method to recover iron and alumina from ironrich bauxite and red mud. Methods for alkaline recovery of aluminum from bauxite residue. Red mud is produced during the bayer process for alumina production.
Red mud a byproduct generated at the aluminium plants all over the world. Composition and properties of red mud in the world have been presented by many researchers in their publications. However, a lot of ironrich bauxite and bayer red mud resources have not been. 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. Used red mud was received from jajarm alumina plant iranian alumina co. Jul 08, 2003 red mud is a byproduct of bauxite processing via the bayer process. The residue called red mud that accumulates in the bottom of the tank consists of fine sand, iron oxide, and oxides of trace elements like titanium. 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. Alumina of calcium aluminate slag was leached using sodium carbonate solutions na 2 co 3 abbr. The red mud involved in the accident is a waste product of the bayer process, which refines bauxite into a form of aluminium oxide called alumina. As a rule of thumb, 4 metric tons of bauxite yields 2 tons each of alumina and red mud, and in turn 1 ton of aluminum metal. Jul 29, 2019 red mud, an industrial waste obtained from alumina plants, is usually discharged into marine or disposed into a landfill polluting the surrounding water, atmosphere, and soil. The performance of red mud adsorbents in the removal of inorganic anions, heavy metals and organic compounds from wastewaters, and gaseous effluents is also discussed. Red mud is a byproduct of bauxite processing via the bayer process.
From the view of main chemical composition and alumina process, red mud in china could be classified into 4 types. Keywords bauxite residue red mud aluminum extraction aluminum. Since red mud consists of iron and aluminumrich phases, it can potentially be processed into cementitious material. Characterization and applications of red mud from bauxite. The next profit margin in the alumina industryred mud. Oct 11, 2012 red mud disposal still remains a major environmental issue in alumina production and the world wide aluminium industry has been constantly trying to find a viable and permanent solution to dispose and reuse the red mud produced enormously during alumina extraction.
Red mud is the industrial waste generated during the production of alumina. With seawater neutralization, the calcium and magnesium ions in the water. Red mud minimisation and management for the alumina industry. Recover iron from bauxite residue red mud iopscience. Geotechnical characterization of bauxite residue red mud. The bayer process is the principal industrial means of refining bauxite to produce alumina aluminium oxide and was developed by carl josef bayer. Leaching behavior of alumina from smelting reduction. Irrespective of its exact composition, the mineral mixture. The red mud used contained 32 % iron in the form of hematite and goethite, 8 % aluminum as aluminum hydroxides and alumina, 4 % titania, 6 % calcium carbonate and desilication product dsp.
Currently, it is stored or dumped on land, or in the oceans near alumina refineries. Analysis on physical and mechanical properties of red mud. Since its inception in the late1800s, the only option was to impound the caustic red mud. Recovery of al2o3, fe2o3 and tio2 from bauxite processing. Neutralization of this red mud would be very much use full and reduces the pollution largely and. Adsorptive removal of phosphate from aqueous solutions. This paper describes the basic characteristics and mineral compositions of rm. In some plants, red muds are further processed to produce aluminum oxides. Unfortunately, for each ton of aluminum produced, around 12 tons of red mud are also produced, creating a massive amount of industrial waste to manage. Alumina, also called aluminum oxide, synthetically produced aluminum oxide, al 2 o 3, a white or nearly colourless crystalline substance that is used as a starting material for the smelting of aluminum metal. It also serves as the raw material for a broad range of advanced ceramic products and as an active agent in chemical processing. Red muds contain significant amounts of iron 20 to 50 percent, aluminum 20 to 30 percent, silicon 10 to 20 percent, calcium 10 to 30 percent, and sodium 10 to 20 percent.
The novel red mud treatment process however aims at turning all of the red mud waste into valuable products and this includes transforming the eaf slag into inorganic fibers suitable for the production of a variety of products commonly known as mineral or slag, rock wool. Alumina is a bright white solid with a trigonal crystal structure, with oxygen atoms in a hexagonalclosepacked arrangement and the aluminium atoms occupying twothirds of the octahedral holes. Leaching behavior of alumina of smelting reduction calcium aluminate slag based on highiron red mud composition was investigated. Apr 06, 2018 associate professor huang said the process, which was being tested in field trials at alumina refineries in australia, had the potential to transform expensive red mud rehabilitation practices at. The first commercial extraction of alumina al 2 o 3 from bauxite has been attributed to henri sainteclaire deville in about 1854 soon after this, in 1888, karl joseph bayer described what is now known as the bayer process, which led to a dramatic reduction in the cost of aluminum metal. Red mud is a product of the bayer process during the production of alumina hairi et al. From a few alumina plants, red mud is deposited on the sea bed under strictly controlled conditions. In general, the composition of the residue reflects that of the nonaluminium components, with. Technological enhancements factors tef were determined for the uranium, thorium, actinium series, their progenies, and the nonseries potassium40 using gamma spectrometry. Red mud tanrai alumina processing plant contains a big content of oxides, such as. The red mud waste dries to a very fine, powdery solid and contains significant amounts of iron, aluminum, calcium and sodium. Bauxite industry in guinea and value opportunities of the.
Alumina red mud from aluminum industry has not been utilized effectively due to its strong alkaline, and so2 is an industrial pollutant which mainly produced by thermal power plants. At present, in india about 10 million tonnes of red mud residue are being generated annually posing very serious and alarming environmental problems. Bauxite residue is the ironoxide rich mine waste from the processing of bauxite ore for the extraction of alumina through the bayer process. Fe 2 o 3, al 2 o 3, sio 2, tio 2, nao, k 2 o, cao and sometimes. The types and concentrations of minerals present in the muds depend on the composition of the ore and processing conditions. Red mud is a toxic byproduct of the industrial process that refines bauxite, raw aluminum ore, into aluminum oxide, or alumina. It is a mixture of compounds originally present in the parent mineral, bauxite, and of compounds formed or introduced during the bayer cycle. Alumina is put through a separate process, electrolysis, to make.
Described herein is a process that converts the red mud into mineral products that can be used for commercial applications. Red mud in an liquid state causes harmful effects to human skin. Red mud is the tailings generated from the production process of aluminum industry and is mainly stacked in openair at present, so how to ensure the stability of red mud stockpile is very important. Red mud rm is a byproduct of extracting of alumina from bauxite. This red mud, or bauxite residue, represents a significant challenge to the industry due to its highly caustic nature and the. Residues from different bauxite have a wide range of composition. The title of the patent is treatment and disposal of red mud generated in the bayer process, au701874. Regarding mud stockpile of guizhou aluminum factory as the research object, this paper studies the physical and mechanical properties of bayer red mud from wetting process, bayer red mud from.
As part of this initiative, the company already sells 200250 ktyr of red mud generated at its nikolayev alumina refinery in ukraine. Investigation of the composition and properties of red mud from domestic alumina processing plant in order to turn its use towards the obtaining of ceramic oxide materials foams is a main objective of the project watoprem pniiptpcca204177, ctr. Therefore, as bauxite breaks down to smaller pieces, new surface area opens and the digestion. The bayer process uses caustic soda, high pressure, and high temperature to leach alumina from ferruginous residue slurry bauxite residue or red mud. The disposal of red mud can present an environmental problem simply because there is so much of it.
The technological enhancement of normally occurring. Bauxite, reserve, alumina, red mud, residue, product. Tables 2 and 3 list the chemical and mineral compositions of red mud that are. The mud primarily contains nonaluminium compounds present in the bauxite ore and left as residues after its refining along with sodium hydroxide used to dissolve aluminium oxide. Alumina production growth in china and the world in the past. The high concentration of iron compounds in the bauxite gives the byproduct its characteristic red colour, and hence its common name red mud. In general, the composition of the residue reflects that of the non aluminium components, with. Initially, the residue is washed, to extract as much valuable caustic soda and dissolved alumina as possible. Alumina production in china in 2014 50 million tonnes. The samples studied were made from a mixture selected.
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