A silicon modulus of enriched bauxite units was obtained. As a result of the autoclave leaching of gibbsitekaolinite bauxite after a twostage enrichment, the maximum extraction of alumina into solution was %. The yield of red mud during the processing of bauxite enriched and calcined at 950 C was %. During the autoclave
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The alumina content of a typical Kaolin is 1525% varying from place to place. Kaolin is highly silicious having around 50% silica. That is the reason it follows a different route of roasting and chloride leaching to extract alumina. Leaching with acids like HCl and H 2 SO 4 [3, 4] is
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There are three primary methods for recovering alumina from aluminum ore such as Bayer process, sintered Bayer process and Pedersen process (Safarian and Kolbeinsen, 2016 ). The summary of these processes are listed in Table 1.
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The specific process included pressure leaching by hydrochloric acidextraction separation of leaching solutiondirect pyrolysis of aluminum chloride solution to produce alumina. As shown in Fig. 1, first, the highiron bauxite was treated by acid leaching, and the solution containing aluminum chloride and ferric chloride was obtained.
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In this paper, a novel process is proposed to extract Al 2 O 3 and SiO 2 from highsilica bauxite without residue discharge, that is, sintering bauxite with Na 2 CO 3 followed by twostep leaching with water and sulfuric acid. The effects of the sintering parameters on the process were investigated, and the phase transformations during ...
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As a hybrid process, bauxite residue undergoes a reductive smelting process with lime addition in an electric arc furnace in order to generate aluminaenriched slag. This slag is subsequently treated with highpressure caustic leaching at moderated (200300 g/l) and high (572762 g/l) sodium hydroxide concentrations.
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Keywords Scandium ·Rare earth elements ·Bauxite ·Bayer process Introduction The Bayer process is the main process applied to obtain alumina from bauxite ore. The mineral is dissolved using sodium hydroxide in digesters, which obtain sodium aluminate in solution and a solid phase called red mud; the two are separated by the clarification ...
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In 2015, the US Geological Survey estimated that over 95% of bauxite was converted to alumina, with the remainder going toward a variety of products such as abrasives, chemicals, proppants, and more. The primary approach to transforming bauxite ore to alumina is known as the Bayer Process.
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The research on pressure leaching started in 1887. Karl Josef Bayer was the first one who proposed to leaching bauxite with sodium hydroxide solution at a temperature of 413453 K to obtain sodium ...
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Red mud is a slimy caustic residue generated from alumina refining of bauxite ores. During the alumina extraction process, about 35 %40 % of the bauxite ores go into the residue as highly alkaline red mud slurry (pH ) which contains 15 %40 % of solid phase in volume [1, 2].Depending on the quality of bauxite ores, producing 1 t alumina basically generates t red mud [].
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Aluminum is primarily produced by refining the bauxite ore to alumina in the Bayer Process, followed by electrolytic reduction to metal in HallHéroult process . ... The leach solution obtained after sulfation roasting and water leaching at optimized conditions (300 °C, mL/g acid, 1 h) consist of g/L Ti, g/L Al, g/L Fe ...
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where x = 1 for monohydrate hard alumina bauxite or monohydrate soft alumina bauxite; x = 3 for the trihydrate alumina bauxite. Among them, trihydrate alumina bauxite is the easiest to leach, with a typical leaching temperature of 140~145 °C and Na 2 O mass concentration of 120~140 g/L. Monohydrate soft alumina bauxite is more difficult to ...
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A novel process involving microwave roasting of slurry mixtures of diasporic bauxite and alkaline solutions followed by dilute alkaline leaching, is proposed for extracting alumina from low grade diasporic bauxite was found that when the mole ratio of m NaOH / (m Al + m Fe) and m Ca /m Si in the slurry mixture was close to 1 and 2, the Al and Si contained in the bauxite were completely ...
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Bayer process alumina production. Bauxite ore is the main raw material used in alumina production. ... The filtrate obtained can be recycled in the Bayer process, and the residue was subjected to highintensity magnetic separation. ... Zhang TA, et al. Thermodynamics study on leaching process of gibbsite bauxite by hydrochloric acid ...
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The alumina in leaching residue with A/S> 10 can be extracted by the Bayer process if more than 90% of silica in HACG will be removed. Therefore, a novel technology of hematite (Fe 2 O 3) involved roastingalkaline leachingBayer digestion process is proposed to extract the silica and alumina in HACG [10, 11]. Kaolinite, the main min
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More than 90% of the world's commercial manufacture of alumina is obtained by hydrochemical sodium hydroxide extraction of bauxite through the conventional Bayer process.
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Experimental Method. In this study, the recovery of precious metals from bauxite ore was examined by a twostage leaching process. The stages of this process were Stage I: Removing iron to a large extent and revealing the solubility conditions of titanium by treating the bauxite ore with oxalic acid, Stage II: Determining the recovery conditions of aluminum from the residue obtained after the ...
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Red mud, also referred to as bauxite residue, is the largest process waste produced during alumina production from bauxite ore by the Bayer method. Approximately 12 tons of red mud are produced for every ton of alumina produced 1. Global red mud manufacturing is anticipated to be 200 million tons annually.
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produce highly purified and fine alumina, some alternative on leaching and precipitation processes were studied. These due to leaching process tends to predetermine the rate of recovery and the purity of alumina whereas a very effective precipitation process can be applied to produce fine size of alumina powder.
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Based on the above technical route, > 96% SiO 2 and 97% Al 2 O 3 in highalumina coal gangue was extracted, respectively. 26 In addition, > 95% of silica by reduction roasting simulated CFBderived coal fly ash with Fe 2 O 3 can be dissolved in alkaline solution and the mass ratio of alumina to silica in the leached residue can increase from to above 20. 25 However, the silica leaching ...
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DOI: /materproc Corpus ID: ; The Efficient Use of Sulfuric Acid in Bauxite Residue Leaching article{Toli2023TheEU, title={The Efficient Use of Sulfuric Acid in Bauxite Residue Leaching}, author={Aikaterini Toli and Dimis Kotsanis and Maria Psoma and Danai Marinos and Panagiotis Davris and Efthymios Balomenos and Dimis Panias}, journal={RawMat 2023}, year ...
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Introduction. Alumina (Al 2 O 3) is a material which has been studied extensively due to its wideranging applications in areas such as adsorbents and is traditionally obtained from the Bayer Process, which recovers aluminium from bauxite via a caustic digestion process, followed by crystallisation of aluminium hydroxides from the sodium aluminate mother liquor (Power et al ...
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A silicon modulus of enriched bauxite units was obtained. As a result of the autoclave leaching of gibbsitekaolinite bauxite after a twostage enrichment, the maximum extraction of alumina into solution was %. The yield of red mud during the processing of bauxite enriched and calcined at 950 °C was %.
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In the industrial production of alumina, there are three main production methods: the Bayer process, sintering process, and combined process (Liu et al. 2014a).The Bayer process is the most commonly used in alumina production (Liu et al. 2007), and more than 90% of alumina is produced by the Bayer process worldwide (Wang et al. 2018).Bayer red mud is an insoluble alkaline solid waste residue ...
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Recycling a ton of aluminum requires only about 5 percent of the energy and saves almost nine tons of bauxite from being hauled from mines. Even antiplastics campaigners agree that recycling ...
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In the Bayer Process to obtain alumina from bauxite, for each tonne of alumina produced, it generates tonnes of residue known as red mud [].The major chemical components of red mud are aluminum, iron, sodium, titanium and silicon; however studies have confirmed the presence of different valuable metals, such as scandium, yttrium and other rare earth elements [2,3,4,5,6].
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Aluminum electrolytic spent anodes obtained from an electrolytic aluminum plant in Yunnan, China, were used as the raw material in the experiment. ... The leaching process was carried out in a temperaturecontrolled magnetic stirrer (DF101S; Shanghai Lichenbangxi Instrument Technology, Shanghai, China) at a temperature of 3090°C, and a ...
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1. Introduction. Red mud (RM) is a waste generated during bauxite processing for alumina production. The most common method for bauxite processing is the Bayer process, where raw material is digested under high pressure by NaOH to obtain a pregnant sodium aluminate solution [].During highpressure leaching, nonsoluble elements such as iron, titanium, and refractory or precipitated during ...
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The Pedersen process is a method to produce alumina from Alcontaining sources, and it is a more materialefficient method than the current commercial Bayer process, since the formation of bauxite residue (red mud) is avoided, and the bauxite can be holistically consumed. The smelting reduction (SR) part of the Pedersen process yields pig iron and a calcium aluminate slag, and the latter is a ...
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The major commercial technology for the production of smelter grade alumina has conventionally been the Bayer process which converts bauxite ore, an aluminum containing ore which typically contains about 50 % Al2O3, into smelter grade alumina that contains over % Al2O3. Another potential source of aluminum that is receiving renewed attention is coal fly ash (CFA), which is a byproduct of ...
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Bauxite residue, known as red mud, is a byproduct of alumina production using the Bayer process. Currently, its total global storage amounts to over billion tons, including about 600 million tons in Russia. The total global storage of red mud occupies large areas, leading to environmental damage and increasing environmental risks. Moreover, it contains a significant amount of sodium ...
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1. Introduction. Red mud (RM) is a solid waste generated by alkali (NaOH) leaching of bauxite by the Bayer process for alumina production [].More than one ton of RM is produced for one ton of alumina (Al 2 O 3), and over 150 Mt of RM is annually stored in landfills and sea [].The RM utilization degree is extremely low due to the high Na, Al, Si, and Ca content because these elements increase ...
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1 Answer +1 vote answered Feb 25, 2020 by Richa01 ( points) selected Feb 25, 2020 by Mohit01 Best answer 1. Bauxite contains impurities like TiO2 Fe2O3 etc. Bauxite is concentrated by digesting the powdered ore in a concentrated solution of NaOH at 473 573 K and 35 bar pressure. Al2O3 is leached as sodium aluminate.
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In this process the ground bauxite is leached with caustic soda (NaOH) to produce soluble sodium aluminate (NaAlO2), leaving the impurities in the insoluble residue. The aluminate solution is then decomposed producing Al (OH)3 which is calcined to produce Al2O3. Alumina Extraction Problem
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Red mud (RM), also known as bauxite residue, is an alkaline solid waste byproduct derived in the extraction process of alumina from bauxite ore. With increasing demands for alumina, the global reserves of RM have reached billion tons in 2018, and it is estimated that an annual increase was approximately 200 million tons [1].
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