Publication:
A comparative study of acid and alkaline aluminum extraction valorization procedure for aluminum saline slags

Date

2022

Authors

Jiménez, Alejandro
Rives, Vicente
Vicente, Miguel Ángel

Director

Publisher

Elsevier
Acceso abierto / Sarbide irekia
Artículo / Artikulua
Versión publicada / Argitaratu den bertsioa

Project identifier

AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-112656RB-C21/ES/recolecta

Abstract

A management process for saline slags, one of the wastes from Secondary Aluminum Production, is proposed. The process begins with a grinding step, followed by washing with water, which removed the fluxing salts but provoking the hydrolysis of AlN, yielding Al(OH)3 and ammonia. Sieving of the solid generated an intermediate and a fine fraction. The first one was rich in metallic aluminum, and can also be returned to the Secondary Aluminum Production. The fine fraction was submitted to a extraction process in acid (HCl or HNO3) or alkaline (NaOH, KOH or CsOH) conditions, under reflux at 90 ºC, obtaining an Al(III) solution that can be used in the synthesis of aluminum-based solids. HCl (1-8 mol/L) and NaOH (1-4 mol/L) were used as reference solutions, HNO3, NaOH and KOH were used under specific conditions; the slag fraction:extraction solution solid:liquid ratio was also varied. The optimum extraction conditions were: extraction time 2 h, solid:liquid ratio 3:10, concentration 3 mol/L for the NaOH medium and 4 mol/L for the HCl medium. More than 30% of the aluminum present in the fraction smaller than 0.4 mm was recovered (the remaining aluminum was present as insoluble phases, corundum and spinel). Acid or basic media can be selected depending on the final use of Al(III) solutions, the basic medium leading to an Al(III) solution with a lower amount of impurities. The hazardousness of the solid obtained after the extraction process was greatly decreased, making possible the use of this solid residue in sectors such as construction.

Description

Keywords

Aluminum saline slags, Industrial waste valorization, High-value-added products, Aluminum extraction

Department

Zientziak / Institute for Advanced Materials and Mathematics - INAMAT2 / Ciencias

Faculty/School

Degree

Doctorate program

item.page.cita

Jiménez, A., Rives, V., Vicente, M.A., Gil, A.. (2022). A comparative study of acid and alkaline aluminum extraction valorization procedure for aluminum saline slags. Journal of Environmental Chemical Engineering . 10,3 .

item.page.rights

© 2022 The Author(s). This is an open access article under the CC BY-NC-ND license

Los documentos de Academica-e están protegidos por derechos de autor con todos los derechos reservados, a no ser que se indique lo contrario.