Comparison of Three Manufacturing Techniques for Sustainable Porous Clay Ceramics

Abstract

This study proposes different manufacturing techniques (manual pelletization, powder pressing, and “shell scaffold”) to obtain lightweight clay ceramics containing recovery raw materials. The sintering in an electrical furnace (1000 °C, 1 h processing time) was conducted by traditional firing from room temperature, for pressed and shell-scaffold samples, while the flash heating (i.e., samples directly put at 1000 °C) was used only for the pellets. The porous materials (porosity 40–80%), functionalized with nutrients (K and P) in amounts to confer the fertilizer capability, gave suitable results in terms of pH (6.7–8.15) and electrical conductivity (0.29–1.33 mS/cm). Thus, such materials can be considered as feasible lightweight clay ceramics, with a positive effect on the soil. These findings permit us to hypothesize a potential use in green roofs or in agronomic applications.

The characteristics and production method between glazed and unglazed of ceramic and porcelain tiles by firing process: A review

“…Pelleting is a form of aggregation that allows the particle size to increase. In the pharmaceutical, food and fertilizer industries, it is used to transform hundreds of compounds from fine powders into manageable particles [19]. As a result, it is strong enough to handle and withstand the special application of sintered raw materials during firing, but still provides nutrients when needed.…”

A review on the production of porous ceramics using organic and inorganic industrial waste

“…Table II summarizes the properties of some porous ceramic materials that were obtained from the use of organic waste as porogenic agents. The data reveal that ceramic bodies with a high level of porosity, low thermal conductivity, and satisfactory mechanical strength can be obtained from waste such as rice husks [12], banana leaves [13], olive stones [14], wheat straw [14], yeast [15] and coffee waste [16,72]. Additionally, it is observed that the most porous ceramic materials produced using organic waste in their composition are applied in the civil construction industry, such as porous clay bricks and foams for thermal and/or acoustic insulation.…”

Evaluating the properties of cellular ceramics prepared with a granite dust and plantain (Musa paradisiaca) peel powder for external wall thermal insulation of buildings

“…Different processing techniques of cellular ceramics include gel casting, replication of a sacrificial foam template, direct foaming of a liquid slurry, burn-out of fugitive pore formers, among others [11,12]. Andreola et al [13] experimented three different manufacturing techniques of porous ceramics and concluded that one technique can be preferable as compared to the others depending on the specific use. The pore-former technique is based on the mixing of the ceramic powder, or its precursors, with a fugitive material that acts as a poreforming agent, followed by the formation of a green body, extraction of the pore-former, and sintering of the ceramic phase [14].…”