Utilização do fosfogesso como matéria prima alternativa no setor da construção civil

Abstract

The surplus generation and final disposal of solid waste is a challenge to society. The National Solid Waste Policy (PNRS) provides guidelines that help in the correct disposal of this waste. Among the solid residues, this work will focus on phosphogypsum, which is generated from the attack of phosphate rock with sulfuric acid for the production of phosphoric acid. Its generation is in proportions of 4 to 6 times greater than phosphoric acid, being considered an environmental liability for the producing companies. This study brings the incorporation of phosphogypsum in clayey soil with proportions of: 4% and 7% by mass of this residue. The soil used was made available by the Universidade Nove de Julho, and because it is an unclassified soil, soil characterization tests were performed. Phosphogypsum was donated by the Institute for Energy and Nuclear Research in dihydrate form. Thus, this research aims to analyze the possibility of using phosphogypsum residue as an alternative raw material for the civil construction sector. With the introduction of this waste in the civil construction sector, it is possible to reduce its disposal in the environment, causing the civil construction sector to reduce the environmental impact due to the amount of natural resources explored and, at the same time, to make this waste raw material. alternative for the sector. To this end, tests were first conducted for geotechnical characterization of the soil and phosphogypsum. Compacted prismatic specimens were also molded, burned in a muffle at 900 ° C for 96h. The strength parameters of the specimens were obtained by means of simple compression and flexural tensile tests. The analysis of these data was performed using descriptive statistics and averaging tests using the SPSS software in order to determine the best possibility of this residue being used in the civil construction sector. From the results obtained from the laboratory procedures, it was possible to perceive the possibility of using phosphogypsum in the civil construction sector for all the proportions of soil with phosphogypsum studied. Because of these results, there may be a possibility to reduce the piles of phosphogypsum stored near the fertilizer industries and at the same time reduce the amount of raw material extracted from the deposits for ceramic use.