O efeito da adição do resíduo de madeiras folhosas processadas no desenvolvimento de placas de revestimento cerâmico

Abstract

The Amazon Forest is a region of great biodiversity that needs sustainable management in order to allow the conservation of its biome. It is necessary to use its resources in a rational way and stimulate sustainability activities to create innovative products, such as the sawdust powders from tropical wood, in order to reduce the incidence of inadequate and disorderly disposal of solid residues in nature, which usually cause damage, even irreversible, to the environment. However, there are no studies on the incorporation of the use of sawdust powder from tropical wood (in natura) in ceramic masses as a partial substitute for clay, for the manufacture of wall coverings for internal use, the focus of this work. Faced with such arguments, the following research question arises: What is the impact of the use of the sawdust powders from tropical woods, generated in the production process of a wood industry, when mixed with clay, in the production of new ceramic products of wall covering, taking into account social, environmental and economic values? In this work, therefore, the objective is to verify the feasibility of incorporating sawdust powders from the wood Pithecelobium racemosum Ducke (Angelim rajado) and Andira parviflora Ducke (Sucupira vermelha) in a ceramic mass composed as porogenic agents for the manufacture of ceramic coatings, in addition to seeking to minimize their impacts on the environment when discarded. The residues were collected in Indústria Mil Madeireira Preciosa Ltda and the clay was collected in the yard of Cerâmica Montemar Indústria e Serviços de Coleta de Resíduos Ltda, located, respectively, in the municipalities of Itacoatiara and Iranduba in the state of Amazonas, Brazil. For characterization, chemical, physical and mineralogical analyzes were carried out to evaluate the behavior of raw materials and mass formulations between clay and sawdust, and the following technological properties after firing were evaluated: Linear Shrinkage (LS), Fracture Resistance (FR) of three-point, Water Absorption (WA), Porosity (P) and Apparent Density (AD), X-Ray Diffractometry and Scanning Electron Microscopy (SEM) according to ABNT NBR 13818/1997 and ABNT NBR ISO 10545/2017. Then, 120 specimens were made in the dimensions of 60x20x5 mm, with 6 samples for each group and with a specific percentage. After drying, these specimens were sintered at temperatures of 750 °C and 850 °C, with a heating rate of 7 °C/min and a burning time of 180 min. The estimation of LS, RF and WA was obtained through a generalized linear model, so that the results were validated through Statistical Analysis, using methods of descriptive analysis, with calculation of frequencies and position measurements (averages and standard deviation). The results showed that the addition of sawdust powders, in the clay, increased the density of the dry soil, indicating a greater packing. Linear firing shrinkage increased with the gradual insertion of residue content in all formulations compared to pure clay, but the results remained within the parameters required by ABNT NBR 13818/1997 in the compositions of AR 2.5%, SV 2.5%, SV 5% and ARSV 10%, configuring a satisfactory result, due to the importance of dimensional control of the product. Although there was a decrease in the mechanical strength of the specimens, caused by the size of the granulometry of the residues, which were greater than 2 μm, the water absorption obtained a significant result after the insertion of sawdust powders from Andira parviflora Ducke (Sucupira vermelha), in the formulations of MC5 (SV 2.5%) and MC6 (SV 5%), when sintered at a temperature of 850 ºC. It is concluded, with these results, that sawdust powders from Sucupira vermelha had better performance as a porogenic agent in relation to Angelim rajado, allowing improvements in the red clay from Iranduba/AM, in this way, it has potential for manufacturing red-based ceramic products, such as BIII-rated porous coatings.