Therefore, the leaching process with dilute HNO 3 has been performed and optimized at a pilot scale for the recovery of scandium from bauxite residue . According to Petrakova et al., leaching with nitric acid could be a problem due to the absorption of nitrate ions on the residue, so that large volumes of water are needed for their removal [ 43 ].
Bauxite residue (BR) is a well promising resource for critical metals, especially scandium (Sc), a rare and expensive metal with increasing applications in advanced technology. Greek BR seems to significantly favor a commercially viable recovery of Sc combining optimized leaching and advanced separation techniques. Leaching with mineral acids emerges as the dominant selection compared to other ...
The process combines carbothermic smelting, acid baking water leaching, and thermal desulfation to efficiently extract the target materials from the bauxite residue without producing hazardous solid residues, while enabling the recovery and recycling of the major process reagents: CaO, SiO 2, and H 2 SO 4. Through systematic testing, the ...
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 ...
The circulation liquid and lime (75% active CaO) for Bayer leaching were obtained from Guizhou, China. Methods. Three different AlFe recovery processes can be found in Fig. shown in Fig. 2, the LRS process means that the bauxite is firstly subjected to Bayer leaching, followed by magnetic roasting of red mud, and then, the roasted red mud would be magnetically separated for ...
Gibbsitic bauxite from Australia was leached by hydrochloric acid in this work. Analysis on kinetics for the extraction of Al 2 O 3 was quantitatively studied. It was concluded that the hydrochloric acid leaching process of gibbsitic bauxite was controlled by chemical reaction. Moreover, the mechanism for the dissolution followed the equation ...
The leaching process with dilute HNO 3 was performed at pilot scale and optimized for the extraction of scandium from bauxite residue ( OchsenkühnPetropoulou et al., 2002 ). Xue et al. (2010) found that at a reaction temperature of 90 °C and an L/S ratio of 3:1, over 80% of the scandium in bauxite residue could be leached by H 2 SO 4.
In the leaching method, bauxite ore is digested with a concentrated solution of N a O H that produces X. When C O 2 gas is passed through the aqueous solution of X, a hydrated compound Y is precipitated. X and Y are N a [A l (O H) 4 ] and A l 2 O 3 ⋅ x H 2 O respectively.
The calcification‑carbonation method is a novel technology recovering Na 2 O and Al 2 O 3 from bauxite residue through mineral transformation, which realizes the harmless treatment of bauxite residue simultaneously. It is mainly realized by two key transformation steps such as calcification transformation and carbonation transformation of the slag phase, and multiple wet process series steps.
In the process of recovering valuable elements from bauxite residue, the acid leaching process method is mainly used at present, which includes hydrochloric acid leaching, sulfuric acid leaching, nitric acid leaching, etc. Nitric acid is highly corrosive and cannot be connected with the medium of the subsequent extraction process, so most of them use hydrochloric acid or sulfuric acid leaching.
Verified by Toppr. Bauxite gets dissolved in hot concentrated NaOH but the impurities do not dissolve in this. So, the method of concentration used for bauxite ore is Leaching. Solve any question of General Principles and Processes of Isolation of Elements with:. Patterns of problems.
The leaching process with dilute HNO 3 was performed at pilot scale and optimized for the extraction of scandium from bauxite residue (OchsenkühnPetropoulou et al., 2002). Xue et al. (2010) found that at a reaction temperature of 90 °C and an L/S ratio of 3:1, over 80% of the scandium in bauxite residue could be leached by H 2 SO 4 .
The process of Leaching is used to concentrate the ore. NaAlO 2 + 2H 2 O → NaOH + Al(OH) 3. Serpek's process: This process is used when the bauxite ore contains a higher percentage of silica as an impurity. In this process, powdered bauxite ore is mixed with carbon (coke) and heated to 1473K in a current of nitrogen.
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 Dimitrios Kotsanis and Maria Psoma and Danai Marinos and Panagiotis Davris and Efthymios Balomenos and Dimitrios Panias}, journal={RawMat 2023}, year ...
In general, the lithium content in bauxite ore is negatively correlated with the alumina content,, the lithium content in bauxite decreases with increasing Al 2 O 3 content. 25,28 Lithium in bauxite tailings 27 can be recovered using acid leaching; however, this leaching process is not selective and the leachate purification process is ...
The lateritic bauxite hydrochloric acid leaching process showed that when the ore granularity was less than 55 μm, the liquid/solid ratio (L/S ratio) was 100:7, the leaching temperature was 373383 K, the leaching time was 120 min and the HCl concentration was 10%, both the leaching rates of Al and Fe were over 95% . But the hydrochloric ...
Due to drawbacks of the direct leaching route from bauxite residue, such as silica gel formation and low selectivity towards these valuable metals, a novel leaching process based on oxidative ...
Bauxite residue (BR), an alkaline industrial waste, is a major byproduct of the alumina production process known as the Bayer process. The Bayer process generates a byproduct known as bauxite residue (red mud). This residue was leached with sulfuric acid in a pilot plant of Mytilineos to recover scandium. Scandium was selectively recovered in pilotscale experiments using ion exchange.
In this study, a novel process has been developed to extract lithium as lithium phosphate from bauxite mine tailings, which includes: 1) leaching with mixed acid (H 3 PO 4 + H 2 SO 4), 2) leachate neutralization, and 3) Li 3 PO 4 preparation. Mixed acid was used to effectively leach lithium (Li) without roasting pretreatment, the Li leaching ...
Principle processflow diagram of bauxite leaching with HCl based on reference [112]. Many metallic elements in bauxite can be leached in an acid solution. Thus, iron, aluminum or other metallic elements are leached and recovered together during the acidleaching process. However, some problems with acid treatment remain, including severe ...
At the same time, as a secondary resource, its aluminum content can reach 50%, which is close to that of mediumgrade bauxite; thus, it can be used as a substitute for bauxite resources. We propose a new method for extracting aluminum from fly ash via leaching. By designing the thermal reaction system of the molten brine, highpurity hydroxyl ...
Thus, this process doesn't look compatible with laterite where the iron content is much higher than typical lowgrade bauxite. Hence, an alternative acid leaching extraction was planned. For any earth material extraction process, the study of the kinetic behavior of element extraction is crucial to make the process efficient.
In order to explore the commercialized applications of the lowgrade bauxite in the refractory industry, a calcination integrated with acid leaching method was adopted to remove the potassium (K) and iron (Fe) from the diasporeillite (DI) type lowgrade bauxite. Following calcining the bauxite at different temperatures, the leaching parameters, including the sulfuric acid concentration ...
The Bayer process is the main method of alumina production worldwide. The use of lowquality bauxites for alumina production results in the formation of a significant amount of technogenic waste—bauxite residue (BR). The Bayer reductive method is one possible way to eliminate BR stockpiling, but it requires highpressure leaching at temperatures higher than 220 °C.
In this process, bauxite residue is smelted at 1500 °C or higher in presence of a flux and a reductant to produce pig iron and slag. Alumina in the produced slag is mainly in the form of calcium aluminate that can be treated with Na 2 CO 3 solution. The leach residue generated from this process is known as gray mud.
The study showed the change in the limiting stage of the alkaline leaching process after water treatment, with the activation energy growing from to kJ/mol.
The bauxite selection that can be insitu leaching mining needs to solve the following problems: (1) whether it is permeable to ensure that the leaching solution can flow in the ore layer; (2) whether it is soluble, which can ensure the leaching rate, the content of beneficial minerals in the leaching solution and the consumption of leaching ...
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