Dynamic Modeling of Yield and Particle Size Distribution in Continuous Bayer Precipitation

Stephenson, Jerry L.; Kapraun, Chris

doi:10.1007/978-3-319-48176-0_123

Cited by 5 publications

(4 citation statements)

References 2 publications

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“…Более 90% глинозема во всем мире получают с помощью щелочного способа Байера [4]. Осаждение гидроксида алюминия из щелочного раствора, содержащего алюминат натрия, является основной стадией процесса Байера, ограничивающего общую скорость глиноземного производства [5,6]. Было проведено множество исследований с целью выяснения механизма декомпозиции и возможных путей увеличения скорости процесса [7][8][9][10][11][12].…”

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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“…Several methods have been proposed to enhance the precipitation rate and speed, such as mechanical or thermal activation of the industrial seed [4,5], active seed and additive application [6][7][8], and operating conditions optimization [9]. Seed surface purification from organic and nonorganic species can also enhance seeded precipitation rate [10][11][12] because adsorbed impurities on the seed surface can reduce the active site availability.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Precipitation of Gibbsite from Sodium Aluminate Solution by Adding Agglomerated Active Al(OH)<sub>3</sub> Seed

Shoppert¹,

Valeev²,

Alekseev³

et al. 2022

Preprint

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The addition of active seed for increasing the precipitation rate leads to the formation of fine Al(OH)3 particles that complicates separation of solid from the mother liquor. In this study, the enhanced precipitation of coarse Al(OH)3 from sodium aluminate solution using active agglomerated seed was investigated. Aluminum salt (Al2(SO4)3) were used for active agglomerated seed precipitation at the initial of the process. About 50% of precipitation rate was obtained when these agglomerates were used as a seed in the amount of 20 g L–1 at 25 °C within 10 h. The agglomerated active seed and precipitate samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). SEM images showed that agglomerates consist of flake-like particles that can be stick together by bayerite (β-Al(OH)3) acting as a binder. The precipitation temperature above 35 °C and the high concentration of free alkali (αk &gt; 3) lead to the agglomerates refinement that can be associated with the bayerite dissolution.

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“…Precipitation of aluminum hydroxide from sodium aluminate solution is the narrowest stage of the Bayer process, as it lasts more than 40 hours and the degree of precipitation of the solution does not exceed 55% [1,2]. However, precipitation determines the quality of the final product -alumina, as the particle size distribution of aluminum hydroxide is retained after calcination [3].…”

Section: Introductionmentioning

confidence: 99%

Improvement of Stirred Tank for Aluminum Hydroxide Seeded Precipitation

Chernyshov

Shoppert

Sarapulova

2019

MSF

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Dynamic Modeling of Yield and Particle Size Distribution in Continuous Bayer Precipitation

Cited by 5 publications

References 2 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

Enhanced Precipitation of Gibbsite from Sodium Aluminate Solution by Adding Agglomerated Active Al(OH)<sub>3</sub> Seed

Improvement of Stirred Tank for Aluminum Hydroxide Seeded Precipitation

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