The high concentration of iron compounds in the bauxite gives the byproduct its characteristic red colour, and hence its common name red mud. Stockpiling and comprehensive utilization of red mud research progress. Abstract rapid industrialization leads to the maximum discharge of waste products which in turn causes the environmental hazards. Phosphate removal by using activated red mud from seydisehir. With up to 4 inches of red mud coating farmland, concerns arose about red muds potential impact on the 2011 planting of corn, alfalfa, and other crops. Red mud in an liquid state causes harmful effects to human skin. Red mud tanrai alumina processing plant contains a big content of oxides, such as. 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. Bauxite, reserve, alumina, red mud, residue, product. Apart from iron oxide, other primary substances within red mud include titanium oxide, residual aluminum oxides, and silica. Corrosion characterization of aluminium 6061 red mud. Making the most of red mud february 24, 2014 issue vol.
Wang and liu, 2012 measured by using xray diffractometer. The bayer process is the principal industrial means of refining bauxite to produce alumina aluminium oxide and was developed by carl josef bayer. China has a target to recycle 10% of all of its red mud, and chalco has already introduced several solutions to recover iron and rare earth metals from red mud waste, so the residues can be used for steel and concrete production. Physical and chemical properties of sintering red mud and. However, a lot of ironrich bauxite and bayer red mud resources have not been timely and effectively recycled, resulting in serious problems of environmental pollution and wastage of resources. With stirring and cooling to 60c, aluminum hydroxide aloh 3 hydrargillite precipitates. The definitive overview of the science and metallurgy of aluminum, magnesium, titanium and beryllium alloys, this is the only book available covering the background materials science, properties, manufacturing processes and applications of these key engineering metals in a single accessible volume.
Red mud is the solid waste residue generated from the alumina refining of bauxite ore, primarily by the bayer process which utilizes caustic soda to dissolve the aluminum silicate. Red mud is about one million times more alkaline than a neutral material. In western countries, about 35 million tons of red mud are produced yearly. Rio tinto is a global leader in aluminium, one of the worlds most widely used metals.
Experimental investigations on mechanical properties of al. Vickers micro hardness tests are performed and the hardness values vary from hv145 to hv177 with an increase in reinforcement from 0% to 15% volume fraction. Bauxite is composed of aluminum hydroxide minerals, including primarily open access. Adding the weak soda washed out of the red mud to the sodium aluminate solution dilutes it and cools it to about 100c. Aluminium plants typically produce red mud, and most of them also generate fly ash.
Fly ash is mainly composed of sio2 and al2o3, thus can be used to absorb the water contained in the red mud and improve the reactive silica content of the cement. Bauxite industry in guinea and value opportunities of the. Red mud was reduced in a tube furnace in an atmosphere of co, co. Composition and properties of red mud in the world have been presented by many researchers in their publications. Rm is mainly made up of oxides of iron, aluminum, silicon and titanium. The value in recovering materials from red mud would have a tremendous impact for the aluminum industry and for the economy. It is the insoluble product after bauxite digestion with sodium hydroxide at elevated temperature and pressure. The metallic element aluminum is the third most plentiful element in the earths crust, comprising 8% of the planets soil and rocks oxygen and silicon make up 47% and 28%, respectively. Main categories of red mud and its environmental impacts. Stateoftheart formation of red mud during industrial processing of bauxite in the sverdlovsk region russian federation is presented. Corrosion characterization of aluminium 6061 red mud metal. Red mud is the solid waste residue of the digestion of bauxite ores with caustic soda for alumina al2o3 production.
Red mud is composed of minerals such as hematite, gibbsite, calcite, quartz, goethite, diaspore, rutile, kaolinite, etc. It comprises of iron, aluminium, titanium and silica along with some other minor constituents. The nalco red mud contains a higher amount of iron oxides, whereas the alcoa red mud is rich in sio 2. A mineralogical assessment on residues after acidic. Though clearly innovative, according to mishra a method for extracting salable products from red mud in the next five years is all but inevitable. The use of any information contained herein by any member or nonmember of the aluminum association is entirely voluntary. Minor amounts of as 24% are also removed from solution via surface adsorption of as onto the al oxyhydroxides. Carbothermic reduction of red mud in an eaf and subsequent recovery of aluminum from slag by pressure leaching in caustic solution. Red mud is a toxic byproduct of the industrial process that refines bauxite, raw aluminum ore, into aluminum oxide, or alumina. Red mud emerges as the waste material during the production of alumina from bauxite in bayers process. It is obtained from hindalco, renikoot district, up. It is a mixture of compounds originally present in the parent mineral, bauxite, and of compounds formed or introduced during the bayer cycle. Possibilities of exploitation of bauxite residue from alumina.
Two step stir casting process is used to fabricate the composites by varying volume fractions of red mud 5%, 10% and 15% volume fractions. 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. These wastes can be a substitute for conventional material, when utilized in a best way. 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. The chemical composition of the two kinds of red mud determined by xrf analyzer is given in table 1. The red mud used for this study was generated in aluminum of greece boeotia, greece s. About 120,000,000 t red mud would be discharged globally every year 1. 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 disasters main threat to crops is not toxic. Methodology red mud will be collected from two different sites of india. Approximately 3540% of the processed bauxite ore goes into the waste as alkaline red mud slurry which consists of 1540% solids and 0. The composition, recycling and utilisation of bayer red mud. Red mud or bauxite residue is a solid waste generated from the bayer process.
May 12, 2016 the most common among the uses of red mud is using it as a building material. Cn102757060b method for dissolving bayer process red mud. Also red mud has been used as building materials 3, catalyst 4, inorganic substrate 5, removal agents 68 and absorbent 911, but all these applications use low amounts of generated red mud. Reclamation of red mud storage area few of red mud storage area is reclamed in china, that is not friendly to the surrounding. Red mud or bauxite residue is a highly alkaline waste generated from alumina refinery with a ph of 10. Red mud is a waste obtained after the removal of aluminium from its ore. This involves refining the mineral ore bauxite to generate aluminum oxide alumina, which gives aluminum when smelting 1. Best practice is not a single onesize fits all prescription to bauxite residue management.
Alumina is put through a separate process, electrolysis, to make aluminum metal. Washing of red mud with distilled water by taking different ratios of red mud and water. Red mud is industrial waste obtained from bayers process that contains different constituents like al2o3, fe2o3, tio2, and na2o etc. Chemistrywise, silicarich red mud seems more suitable for geopolymerization and the silicatoalumina ratio is 2. With the rapid development of iron and steel industry and aluminum industry, highquality iron ore and bauxite resources become increasingly tense. In addition to iron, the other dominant particles include silica, unbleached residual aluminum, and titanium oxide. A study on the characterization of red mud harjeet nath1, abanti sahoo2.
Its composition depends upon its parent material from which it is produced liu and wu, 2012. The chemical composition of the red mud is listed in table1and shows the major constituents of this material such as iron iiioxide, aluminum oxide, calcium oxide and silicon dioxide analyzed by. 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. It can be seen from table 2 that the main composition of the red mud from the sintering process is. Because of the complex physicochemical properties of red mud it is very challenging task for the designers to find out the economical utilization and safe disposal of red mud. The use of red mud as secondary resource to recovery of valuable metals can be one of the solutions to these problems.
By increasing the red mud upto 40% to the soil with 3% lime, the best results were come out at 20% red mud soil mixture. The comprehensive utilisation of red mud utilisation in. The remaining iron, titanium, sodium, silica and other impurities are all discarded. Development of aluminum composites using red mud as. Red mud a hazardous industrial solid waste red mud world.
Microtest approaches like xrf, xrd and sem and routine soil tests were applied to analyze the chemical composition, mineral composition, microstructure and basic physical property indicators of three kinds of red mud, which were the bayer red mud, sintering red mud as well as the mixed red mud prepared by sintering red mud and the bayer red mud at the mixture ratio of 1. The bayer process also creates an insoluble mixture of compounds known as red mud rm, which, at present, is regarded as waste. In the institute of metallurgy of the ural branch of the russian academy of sciences, red mud is utilised by introducing it into the. Toxic red mud flooded thousands of homes this week near the town of devecser, hungary.
Which component of the red mud is the more dangerous. In comp arison with red mud it is more solid, because it contains higher portion of solid co mponent, but it has lower content of fe 2o 3 and na 2o. 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. Active in the sector for more than 110 years, today we operate largescale, highquality bauxite mines and alumina refineries and the worlds most modern and competitive aluminium smelters portfolio. The addition of red mud delayed the onset of corrosion and possibly also reduced the corrosion rate. This waste product is known from its oxidised iron content as red mud. Information on some aspects of the up to now practised disposal of red mud is available at the works of s. The red mud waste dries to a very fine, powdery solid and contains significant amounts of iron, aluminum, calcium and sodium. 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. A new project, involving high pressure filtering and dry disposal and reuse of red mud, is under implementation. Approximately, 3540% of the processed bauxite ore goes into the waste as alkaline red mud slurry which consists of 1540% solids, and 1. In the method disclosed by the invention, the structure and composition of red mud are changed by adopting calcification transformation and pressurizing calcification transformation methods, so that dealkalization and extraction of aluminum can be realized. With rapid growth of aluminum output in recent years, the discharge amount of red mud increases accordingly.
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. The red color is caused by the oxidized iron present which can make up to 60% of the red mud. A typical chemical composition is shown in table 1 and a typical. In addition to iron, the other dominant components include silica, unleached residual alumina, titanium oxide, and caustic. The mud primarily contains non aluminium compounds present in the bauxite ore and left as residues after its refining along with sodium hydroxide used to dissolve aluminium oxide. It is important to differentiate between the alkaline waste generated in the bayer process and the tailings generated during the mining of bauxite. Red mud is a product of the bayer process during the production of alumina hairi et al. The types and concentrations of minerals present in the muds depend on the composition of the ore and processing conditions. There are different aluminum production processes to different bauxites. Dicalcium silicate in red mud is also one of the main phases in cement clinker, and red mud can play the role of crystallization in the production of cement clinker. As the temperature and pressure increases, the solubility of red mud decreases with sodium hydroxide nie et al. Red mud rm is a solid waste product obtained from aluminum industries which is reddish brown in color. Stockpiling and comprehensive utilization of red mud. Effect of red mud on the corrosion of reinforced concrete.
Red mud is the tailings generated from the production process of alumina in aluminum industry. While the association believes that its compilation procedures are reliable, it does not warrant. The unique project to produce red mud powder has been commissioned in a fully mechanised and automated plant. The red colour is caused by the oxidized iron present, which can make up to 60% of the mass of the red mud. This produces a sodiumaluminium solution from which pure al oh3 s precipitated, later to be calcined to produce oxide, from which the metal is recovered. Dealing with red mud by product of the bayer process for. Effect of replacement of cement by red mud on the properties of concrete.
The disposal of red mud leads to a serious environmental threat because of its tiny particle size and high alkaline value. What are the aluminum properties that confer it a widespread use. The primary component of red mud is iron oxide which gives the substance its red color. Total element composition will be analyzed by xray fluorescence spectroscopy xrf mineral composition will be determined by xray diffraction xrd extraction of ree.
Red mud is a byproduct of aluminum production, in which alumina is extracted from bauxite ore via the bayer process. Its eds analysis reveals the presence of oxides of iron, silicon, titanium, zirconium etc. 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. Mineralogy and chemical composition of sampled red mud optimum condition for ree extraction from red mud compounds those could be removed from hospital waste by red mud references. 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. Table i chemical composition of aluminium 7075 alloy red mud is a waste obtained after the removal of aluminium from its ore. Characterization and comprehensive utilization of red mud. Figure 3 shows that removal efficiencies were increased with increasing phosphate concentration up to 30 mg l1 phosphate then decreased. The corrosion of steel bars embedded in concrete containing varying amounts of red mud up to 30% of the total binder was tested by electrochemical impedance spectroscopy eis, under partial immersion in a sodium chloride solution. A study on microstructure composition of unsaturated red mud. In some plants, red muds are further processed to produce aluminum oxides. The final red mud contains a residual level of caustic liquid or alkalinity, with a ph of approximately.
Expected outcome the following outcomes are expected. The bayer process is the cornerstone of global aluminum production. 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. 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. The use of red mud not only increases the compressive and tensile strength of products made by this method, it also serves as a colourant.
Analysis on physical and mechanical properties of red mud. The team was able to efficiently treat red mud particulates with unneutralized vaaa copolymers, down to a vaaa solid composition of 4. A typical chemical composition is shown in table 1 and a typical mineralogical composition is shown in table 2. Most alumina refineries are local is the north of china, where is aried and semiaried climate. How aluminum is made material, manufacture, making, used. Hence, the synergistic use of red mud and fly ash makes the aluminium industry more profitable due to the reduced transportation costs of the waste materials and, ultimately, facilitates these industries with better management plans. Bauxite residue management australian aluminium council. We cant afford to keep collecting red mud in ponds, he opined.
The key point is to find or to acclimatize plants which are salttolerant and alkalitolerant, but not alien species. Jul 08, 2003 red mud is a byproduct of bauxite processing via the bayer process. Behavior of aluminum, arsenic, and vanadium during the. Red mud chemical composition is presented, and an analysis of existing ways in which they are utilised is executed. O, cao and sometimes a high concentration of valuable metal elements. In nature, aluminum is found only in chemical compounds with other elements such as sulphur, silicon, and oxygen. Red mud leachate ph collected from ajka, hungary is neutralized to 99% al is removed from solution during the formation of an amorphous boehmitelike precipitate and dawsonite. The utilisation and recycling of red mud is currently a crucial issue. Dealing with red mud by product of the bayer process. Described herein is a process that converts the red mud into mineral products that can be used for commercial applications. 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. Recovery of al2o3, fe2o3 and tio2 from bauxite processing. Similarly to the change of chemical and minera logical composition of bauxite in dependence on its deposit, the composition of waste mud changes, too. Analysis of alumina red mud wet flue gas desulfurization.
Red mud is produced during the bayer process for alumina production. Chemical and biological leaching of aluminum from red mud. 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. 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. 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. Table 1 chemical composition range % for bauxite residue for main components. This red mud, or bauxite residue, represents a significant challenge to the industry due to its highly caustic.
33 103 1466 234 329 276 252 1390 1258 1472 158 1352 630 1008 247 829 585 1349 1141 568 132 1237 615 958 1338 414 626 538 453 83 1412 54 825 589