Influence of pregranulation and low-pressure compaction on the properties of ceramic materials incorporating clay and spent coffee grounds

Spent coffee grounds (SCG) possess the potential to serve as an effective pore-forming additives ceramic materials productions. Nonetheless, a significant challenge arises when attempting to incorporate substantial quantities SCG, leading to a loss of consistency for extrusion moulding. Additionally, a drawback includes the pronounced drying shrinkage observed high SCG-content masses during plastic clay body moulding. In this study, the pregranulation process was employed to overcome these issues and produce a new material. SCG, in quantities of up to 20% by weight, were granulated with clay into assorted sized granules before being subjected to low-pressure pressing (0.05, 0.15, 0.25, and 0.5 MPa). The resulting samples underwent drying and firing, followed by evaluation of volume density, water absorption, compressive strength, and thermal. This article highlights the distinctions between materials shaped from plastic clay bodies and those formed using pregranulation. The findings demonstrate that by employing clay pregranulation process with or without the addition of spent coffee grounds, it is possible to produce low-density ceramic materials possessing excellent thermal insulation properties and sufficient strength. •Pregranulation allows to obtain thermal insulation material of sufficient strength.•Pregranulation of mass with SCG avoids consistency problems and reduces shrinkage.•Properties pregranulated material depend on granule size and moulding pressure.