No abstract

Throughout the world, the generation of wastes is increasing in quantity and diversity at a rapid rate. Effective and efficient methods must be developed to correctly dispose and recycle the wastes produced. It is also necessary to reduce the non-renewable resources used and lower the impact on our environment. In 2017, over 13.5 million square meters of tiles were produced globally, and the demand for ceramic tiles has escalated along with social development. There has been an increasing incentive to recycle waste materials in ceramic tiles due to the high heterogeneity of the raw materials, and the matrix for creating ceramics being flexibly interchangeable. The objective of this paper is to review and discuss the various recycling options of waste materials in the production of ceramic tiles. Past experimentation includes the addition of glass, coal ash, municipal solid waste ash, sewage sludge, and mining and ore wastes in ceramic tiles. They were used as an additive or substitute for the key components of the ceramic tiles. The results show a general enhancement to the physical and mechanical properties of the tiles with minor adverse effects on the aesthetics. Furthermore, when recycled with toxic wastes, the heavy metals were found to be immobilised during the firing process of the tiles. Therefore, the addition of wastes in tiles offers a sustainable solution to a growing pollution problem, in addition to decreasing the consumption of natural resources utilised in the manufacturing of tiles. However, further research and developments are essential.

Cigarettes are one of the favoured commodities on our planet. However, the annual consumption of 5.7 trillion cigarettes and 75% littering rate results in cigarette butts (CBs) being one of the most critical environmental issues. The leachate of heavy metals and toxic chemicals is polluting our ecosystem and threatening the wildlife species. Therefore, it is crucial to find effective and efficient recycling methods to solve the growing CB waste issue. In this study, unglazed fired ceramic tiles were manufactured with 0%, 0.5%, 1.0%, and 1.5% shredded CBs by dry mass to investigate the feasibility of the proposed sustainable recycling method. The chemical and mineralogical characterisation, density, shrinkage, bulk density, breaking strength, water absorption, and modulus of rupture were investigated and compared with the Australian Standards for ceramic tiles (AS 4459). The results revealed that tiles incorporating 0.5% CBs by mass demonstrated the greatest performance compared to the other mixtures. The water absorption for all tile–CB mixtures was found to be greater than 10%, with a positive growth tendency. The addition of 0.5% CBs by mass slightly improved flexural strength from 15.56 MPa for control samples to 16.63 MPa. Tiles containing 0.5% CBs by mass satisfied the modulus of rupture and water absorption limits for group III class according to the Australian Standards (AS 13006), and they may be suitable to be used as wall tiles. The result of a simulation equation predicts that an energy savings of up to 7.79% is achievable during the firing process for ceramic tiles incorporating 1% CBs by mass.