The crystallization mechanism of Al(OH)3 from sodium aluminate solutions

Synthesis of high-surface-area γ-Al2O3 from aluminum scrap and its use for the adsorption of metals: Pb(II), Cd(II) and Zn(II)

“…According to Kim et al [30], the poorly organized structure of bayerite is due to the oxolation reactions being less favored at the isoelectric point. Li et al [32] revealed that the crystal growth of bayerite and gibbsite follows different pathways and, as can be seen in the results of the present report, the crystal growth of the bayerite and gibbsite were strongly influenced by the precipitation pH. Next, the XRD pattern of the aluminum oxide obtained by thermal treatment of Gel 8-80 at 500 • C is attributed to the formation of poorly crystalline chi-alumina, and is very similar to that found by Meephoka et al [33], Mekasuwandumrong et al [34], Vieira-Coelho et al [35] and Tsuchida and Ichikawa [36], with characteristic broad peaks located at 37 • , 40 • , 46 • , 60 • and 67 • .…”

Uticaj Dodatka Glukoze Na Specifičnu Površinu I Teksturalne Osobine Nano Kristalne Mezoporozne Alumine

“…bajerit, nordstrandit, slabo kristalni bemit [1,2,4]. Kristalizacija dobro kristalnog bajerita uglavnom preovlađuje iz razrijeđenih rastvora aluminata (≤ 1M NaOH) [8], dok kod koncentrovanih rastvora (≥2,5 M NaOH) [7,8] preovlađuje gibsit. Rastvori srednjih koncentracija (1,0-2,5 M NaOH) daju smješu gibsita i bajerita.…”

Statistical Modeling of the Industrial Sodium Aluminate Solutions Decomposition Process

“…[3] Because of the complexity of Bayer liquor speciation, the mechanisms of Al(OH) 3 crystallization are still not understood completely and are the subject of considerable research effort. [4] During Al(OH) 3 crystallization, growth and aggregation of the crystals occur simultaneously.…”

“…[5] Investigations of the gibbsite nucleation from the synthetic sodium aluminate solutions revealed that this process is accelerated in saturated solutions [6] yielding large crystal grains as the result of their aggregation. [4] Also, recent investigations indicated that the introduction of certain ions in the aluminate solution influences the crystallization rate and the size of obtained gibbsite crystals. [7][8][9][10][11][12][13] The crystallization mechanism of Al(OH) 3 from sodium aluminate solutions was investigated by Li et al, [4] they indicated that the mineral form of obtained crystals, as well as their size distribution, depends on the concentration of the solution at temperatures ranging between 338 K (65°C) and 343 K (70°C).…”

“…[4] Also, recent investigations indicated that the introduction of certain ions in the aluminate solution influences the crystallization rate and the size of obtained gibbsite crystals. [7][8][9][10][11][12][13] The crystallization mechanism of Al(OH) 3 from sodium aluminate solutions was investigated by Li et al, [4] they indicated that the mineral form of obtained crystals, as well as their size distribution, depends on the concentration of the solution at temperatures ranging between 338 K (65°C) and 343 K (70°C). This was also proved in the investigations published by Dash et al [14] The kinetics of the gibbsite crystallization from the caustic sodium-aluminate solution, as well as size and the shape of obtained particles, depend on the following parameters of the process: temperature, alumina/caustic ratio, amount and size distribution of the crystallization seeds, stirring speed, and the presence of activation ions added to the solution.…”