Cleaner Design and Production of Lightweight Aggregates (LWAs) to Use in Agronomic Application

Carmen Martínez-García,Luisa Barbieri,Isabella Lancellotti,Romina D Farías,Fernanda Andreola,Mª Teresa Cotes-Palomino

doi:10.3390/app11020800

Carmen Martínez-García, Luisa Barbieri + Show 4 more

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https://doi.org/10.3390/app11020800

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Abstract

This research focused on the obtainment of sustainable lightweight aggregates (LWAs) for agronomic application. The cleaner production is based on saving matter through the valorization of waste available in industry as a substitute of clays into the formulation of the lightweight aggregates (LWAs). Three different types of clays (white, black, and red) and alternative raw materials were blended. Cattle bone flour ash (CBA) and a fertilizer glass (FG) were used to introduce K and P into the mixture in amounts suitable for fertilizer application, and a sewage sludge from a brewery wastewater treatment plant was used as pore forming agent. For the production of the LWAs, we mixed different percentage of waste in two different clay mixtures, which were thermally treated at 1000 °C for 1 h. Technological parameters such as loose bulk and oven dry density, total porosity, water absorption capacity, pH, and electrical conductivity were determined to evaluate the potential use of LWAs as a growing media. Moreover, scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) techniques were used, and leaching tests were performed to complete the samples’ characterization. The results indicated the potential for manufacturing high-quality LWAs for the agronomic field by using energy-saving and matter-processing involving low temperatures with respect to the conventional process.

Highlights

Ceramics materials are extendedly studied as an alternative valorization of hazardous and non-hazardous waste and by-products for the production of sustainable construction materials to improve building energy savings [1] as an alternative to landfill disposal.To deal with such problems, more attention has been paid to the development of sustainable clay bricks, such as those made from kindling from vine shoot [2], paper sludge [3], olive mill wastewater and spent coffee [4], grape and cherry seeds [5], sawdust and sugar cane ash [5], and textile laundry sludge [6]
The chemical analysis (XRF) results reported in Table 3 show that white, black, and red clays contained high silica (SiO2 ) and alumina (Al2 O3 ) quantities, typical for these minerals, as well as iron oxide (Fe2 O3 ), with red clay being the one with the highest values of the three oxides mentioned
Regarding the other raw materials, we found that brewery wastewater treatment plant (BS) showed a high loss on ignition (LOI) (53.80%), probably due to organic matter content and carbonates (18.52% de calcium oxide (CaO)), making it suitable as a poring agent, while

Summary

Introduction

Ceramics materials are extendedly studied as an alternative valorization of hazardous and non-hazardous waste and by-products for the production of sustainable construction materials to improve building energy savings [1] as an alternative to landfill disposal. To deal with such problems, more attention has been paid to the development of sustainable clay bricks, such as those made from kindling from vine shoot [2], paper sludge [3], olive mill wastewater and spent coffee [4], grape and cherry seeds [5], sawdust and sugar cane ash [5], and textile laundry sludge [6]. In terms of number of papers on this matter over past years, the publication rate has increased from 1 to 2 articles per year from the 1990s to 15–20 papers in recent years [28], demonstrating the great interest in this field; some topics are still open, such as the application lightweight aggregates (LWAs) in the agronomic field

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Conclusion