Analysing the chemical composition of man-made materials resultant from the production of primary aluminium in order to find cost-effective recycling techniques

Nemchinova, N. V.; Tyutrin, A. A.; Бараускас, А. Э.

doi:10.17580/tsm.2019.12.03

Cited by 7 publications

(2 citation statements)

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“…Глинозем является основным сырьевым продуктом в производстве алюминия, поэтому вместе с увеличением выпуска алюминия происходит рост производства глинозема. В условиях возрастающих цен на сырье и энергоносители, роста требований к качеству продукции возникает необходимость в постоянном совершенствовании технологического процесса [1][2][3]. Более 90% глинозема во всем мире получают с помощью щелочного способа Байера [4].…”

Section: Introductionunclassified

Improving decomposition efficiency of aluminate liquor through preparation and introduction of active seed during the decomposition process

Alekseev,

Loginova,

Chetyrkin

et al. 2023

jour

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The aim is to determine the optimal parameters for the preparation and dosing of active seeding (ﬁnely dispersed aluminium hydroxide) to control the decomposition of aluminate liquor in the Bayer process. Laboratory tests were carried out on a temperature-controlled rotating water bath (Intronics, Australia). The granulometric analysis of the obtained aluminium hydroxide was carried out using the VideoTest image analysis system and a Carl Zeiss Axioskop-40 microscope (Germany) supplemented with Image Analysis software. Finely dispersed aluminium hydroxide (active seed) was obtained by mixing an alkaline aluminate solution and recycled water in various ratios. The ﬁlling order of solutions was determined – ﬁrst, recycled water, followed by cooled alkaline aluminate solution. Optimal conditions for the preparation of active seeding were established: the solution was held for 48–72 hours at 50°C at an aluminate solution to recycle water ratio of 60% and 40%, respectively. The dosing of the obtained active seeding into the head decomposers was examined. It was demonstrated that using active seeding in continuous decomposition mode stabilises the particle-size distribution of the production-grade aluminium hydroxide. The presence of active seeding allowed the initial decomposition temperature to be reduced from 62°C to 58°C without altering the particle-size distribution of aluminium hydroxide. In addition, the study conﬁrmed the positive effect of active seeding on increasing the degree of decomposition of the aluminate liquor up to 1.5%. Therefore, based on the research results, it was established that the use of the new method for preparing and dosing active seeding into the main decomposers leads to the intensiﬁcation of the decomposition process in alumina production.

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Section: Introductionunclassified

Improving decomposition efficiency of aluminate liquor through preparation and introduction of active seed during the decomposition process

Alekseev,

Loginova,

Chetyrkin

et al. 2023

jour

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“…Solid waste is only partially used in other industries, while the majority is stored at landfills and mud basins. In this regard, developing solutions aimed at improving the environmental performance of the aluminum electrolysis due to the use of technogenic raw materials in the fundamental technique or other industries [11][12][13][14][15][16] is a critical task.…”

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confidence: 99%

Hydrometallurgical Processing of Spent Carbon Lining to Extract Valuable Components for Cryolite Production

Nemchinova

2021

SSP

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The technique of mathematical modeling using the Selector software package has been applied to study the leaching of fluorine from the carbon part of the aluminum electrolysis cell spent lining. Based on the model obtained, the effects of the solvent (caustic soda Na2Oку) concentration and the ratio of liquid and solid phases in the pulp on the fluorine extraction have been assessed. The research object was the lining samples by the RUSAL Krasnoyarsk JSC. A thermodynamic assessment of the spent carbon lining components behavior during the alkaline processing has been performed with the introduction of three solvent concentrations into the model: 12.5, 17.5, and 25.0 g/dm3. According to the model solutions, the maximum fluorine extraction (up to 90 %) is achieved when using a reagent with the Na2Oку concentrations of 12.5 and 17.5 g/dm3 and a liquid to solid ratio of 8.5÷10:1. Using the model, the phase composition of the cake and the forms, in which fluorine remains in the solid residue (cake), have been determined. Laboratory studies confirm the convergence of the simulation results with the experimental data: solutions have been obtained to crystallize out cryolite (with fluorine and silica content of 50–53 % wt. and 0.11÷0.53 % wt., respectively), which is in demand in the electrolysis of cryolite-alumina melts.

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Processing of finely dispersed technogenic raw materials for aluminum production in order to extract valuable components

Nemchinova¹,

Бараускас²,

Тютрин³

et al. 2021

Izv.VUZ. Tsvet. Met.

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The paper provides the results of experiments on the hydrometallurgical processing of finely dispersed technogenic raw materials for primary aluminum production in Soderberg cells (case study of the Irkutsk Aluminum Smelter) – aged sludge. The components of this sludge are dust from electrostatic precipitators (79.7 %), wet gas cleaning sludge (4.4 %) and coal froth flotation tailings (15.8 %). According to the grain-size analysis carried out, aged sludge sample particles have a size of –50 μm. According to the chemical composition analysis of the sludge sample, main components in it are carbon, cryolite, chiolite with a small amount of other compounds (corundum, ralstonite, spodumene, fluorite). Fluorine leaching experiments were carried out with a 2 % sodium hydroxide solution at a stirrer speed of ~1020 rpm. Using the mathematical planning of a three-factor experiment, it was found that the maximum concentration of fluorine in the solution (15.844 g/dm3) is achieved with the following optimal parameters of fluorine alkaline leaching: temperature of 90 °C, liquid-to-solid ratio of 9 : 1, and time of 90 min. The multidimensional polynomial equation was obtained for fluorine alkaline leaching from aged sludge. Cryolite was obtained from fluorine-containing solutions (by the reaction of sodium fluoride interaction with sodium bicarbonate and an aluminate solution), which was confirmed by X-ray phase analysis data.

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Analysing the chemical composition of man-made materials resultant from the production of primary aluminium in order to find cost-effective recycling techniques

Cited by 7 publications

References 0 publications

Improving decomposition efficiency of aluminate liquor through preparation and introduction of active seed during the decomposition process

Improving decomposition efficiency of aluminate liquor through preparation and introduction of active seed during the decomposition process

Hydrometallurgical Processing of Spent Carbon Lining to Extract Valuable Components for Cryolite Production

Processing of finely dispersed technogenic raw materials for aluminum production in order to extract valuable components

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