Reaction Behavior of Autoclaved Aerated Concrete and Sodium Aluminate at Mild Alkaline and Acid Hydrothermal Conditions

Model for AAC Recycling

authored by

Andrea Hartmann, Josef C. Buhl

Abstract

Recyclable fractions such as calcium and sodium aluminosilicates including zeolite sodalite (SOD) were obtained from hydrothermal treatment of autoclaved aerated concrete (AAC) waste material under addition of sodium aluminate. Three experimental series were performed using hydrothermal conditions at temperatures of 80°C and 180°C (autogeneous pressure) and AAC aluminate mass ratios of 0.8 and 2.0. Different solvents were applied in each series; whereas the reactions were carried out in water or 1-molar NaOH, a special two-step process was developed, starting with acid leaching of AAC (1-molar citric acid), followed by alkaline treatment of the whole slurry in 1-molar NaOH. Final products were analyzed by X-ray powder diffraction. Selected samples were further investigated by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The results exhibit model character for new ways of resource recycling of AAC.

Organisation(s)

Institute of Mineralogy

Type

Article

Journal

Journal of Materials in Civil Engineering

Volume

24

Pages

441-450

No. of pages

10

ISSN

0899-1561

Publication date

01.04.2012

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Civil and Structural Engineering, Building and Construction, General Materials Science, Mechanics of Materials

Sustainable Development Goals

SDG 12 - Responsible Consumption and Production

Electronic version(s)

https://doi.org/10.1061/(ASCE)MT.1943-5533.0000392 (Access: Closed)