Work

Influence of Synthesis Route on Composition and Main Properties of Mullite Ceramics Based on Waste

Year: 2025

Type: article

Abstract: , is a material with excellent thermal and mechanical properties. Two types of waste sand, rich in impurities, were employed as precursors for mullite ceramic synthesis. Two different synthesis routes were used: (i) solid-state reactions involving a sand and bauxite mixture, and (ii) precipitation synthesis, where alumina was deposited on sand particle surfaces; the sintering process was performed at temperatures ranging from 1300 °C to 1400 °C. Mullite was obtained as the main phase when the ceramics were obtained by solid-state reactions opposite to the second method, in which a composite ceramic with a specific microstructure, i.e., sand particles embedded in a matrix formed by alumina crystals, was assessed by electronic microscopy. The main properties, i.e., the apparent density, open porosity, compressive strength and thermal expansion coefficient (CTE) of the obtained materials were influenced by the composition and microstructure as well as the sintering temperature. The ceramics in which mullite was the main phase had slightly lower CTE's and did not exhibit any phase transition in the 20-900 °C range. The results presented in this article highlight the importance of the synthesis route correlated with the nature of the precursors, the type and amount of impurities and the sintering temperature.

Source: Materials

DOI: 10.3390/ma18051098

Authors: Alina-Ioana Badanoiu, Stefania-Paula Stoleriu, Alexandru-Cosmin Carocea, Mihai-Alexandru Eftimie, Roxana Trusca

Institution: Universitatea Națională de Știință și Tehnologie Politehnica București

Language: English

Topic: Recycling and utilization of industrial and municipal waste in materials production

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

SDG: Responsible consumption and production

Open Access status: gold

Estimated APC paid: $3,137