Avaliação dos efeitos da adição de agregados reciclados de Al2O3-SiC-C e Al2O3-ZrO2-C em concretos refratários

Abstract

Refractory materials after use in industrial applications are historically disposed as waste in controlled landfills. However, some of these materials have the potential to be recycled contributing to environmental and economic sustainability. The major challenge in this area is the development of cost-effective technologies that enable the recycling of refractory waste. In this sense, this work aimed to evaluate the effects of the addition of recycled aggregates of Al2O3-SiC-C and Al2O3-ZrO2-C obtained by the segregation, selection and crushing of refractory waste from charging ladle, torpedo ladle car and slide gate plates. The main properties and characteristics of specimens made of refractory concrete were evaluated. Laboratory results indicated that physical characteristics and properties were not negatively affected. In addition, a lower corrosion wear rate and higher thermal shock damage resistance were observed for specimens with up to 20% recycled aggregates compared to specimens non-recycled material. Post-mortem analysis of Impeller KR containing recycled in their composition indicated that the recycled aggregates remain preserved so that there were no negative effects on refractory lining properties. The combination of laboratory and industrial results provided indications that the incorporation of recycled aggregates with characteristics compatible with the refractory base product is an attractive alternative to develop refractories with compromise between corrosion resistance and fracture resistance The industrial performance of the studied compositions was about 40% higher than the traditionally molded parts without recycled. These results point out to new perspectives for the use of refractory waste whose intrinsic quality allows the successful incorporation into refractory products.