Valorization of rice straw waste: Production of porcelain tiles

Abstract

The rice industry generates huge amounts of rice straw ashes (RSA). This paper presents the results of an experimental research work about the incorporation of RSA waste as a new alternative raw material for production of porcelain tiles. The RSA replaces, partially or completely, the non-plastic raw materials (quartz (feldspathic sand in this research) and feldspar), that together with the clays, constitute the major constituents of formulations of porcelain tiles. A standard industrial composition (0% RSA) and two more compositions in which feldspar and feldspathic sand were replaced with two percentages of RSA (12.5% RSA and 60% RSA) were formulated, keeping the clay content constant. The mixtures were processed, reproducing industrial porcelain tile manufacturing conditions by the dry route and fired at peak temperatures varying from 1140-1260 °C. The results showed that additions of 12.5% RSA in replacement of feldspar and feldspathic sand allowed producing porcelain tiles that did not display marked changes in processing behaviour, in addition to obtain a microstructure and the typical mineralogical phases of porcelain tile. Thus, an alternative use of an agricultural waste material is proposed, which can be translated into economic and environmental benefits.