Process Design Aspects for Scandium-Selective Leaching of Bauxite Residue with Sulfuric Acid

Minerals

Lamprini-Areti Tsakanika¹  Theopisti Lymperopoulou¹  Konstantinos Hatzilyberis¹  Maria Ochsenkühn-Petropoulou¹  Paraskevas Georgiou¹  Nikolaos Defteraios¹  Fotios Tsopelas¹  Klaus-Michael Ochsenkühn¹ 

[1] School of Chemical Engineering (Chem. Eng.), National Technical University of Athens (NTUA), 9 Iroon Polytechniou St., 15780 Athens, Greece;

关键词: Scandium;    REEs;    bauxite residue;    selective leaching;    process design aspects;    thin film diffusion model;    unyielding core;    specific recovery;   

DOI  :  10.3390/min8030079

来源: DOAJ

【 摘 要 】

Aiming at the industrial scale development of a Scandium (Sc)-selective leaching process of Bauxite Residue (BR), a set of process design aspects has been investigated. The interpretation of experimental data for Sc leaching yield, with sulfuric acid as the leaching solvent, has shown significant impact from acid feed concentration, mixing time, liquid to solids ratio (L/S), and number of cycles of leachate re-usage onto fresh BR. The thin film diffusion model, as the fundamental theory for leaching, either with constant particle size for selective leaching, or with shrinking particle size for less- or non-selective leaching, interprets the relevant experimental data. In both cases, a concept for an unyielding core supplements the basic model. Especially for the selective leaching mild conditions, the simplest model version agrees with the experiments, since both prove 1st order kinetics, while for extreme conditions, a combined conversion rate model with diffusion and chemical reaction inside particles is proposed. The maximization of Sc recovery per unit of consumed solvent emerged as highly critical for the process economics.

【 授权许可】

Unknown