Produção de placas de forro com a reciclagem de gesso

Abstract

The theme of this research arose from the need to evaluate proposals for methodologies for the recycling of gypsum, in view of the prohibition by the state public prosecutor of the waste disposal pits in erosion and landfill sites. The prohibition finds support in the scientific literature indicate that the deposition of gypsum waste in environments of low pH, in presence of moisture, under anaerobic conditions, and also with the presence of bacteria that act as sulfate-reducing, can produce hydrogen sulfide , which at high concentrations is toxic product. In this sense, the study evaluated a proposed methodology for the production of lining plates with recycled gypsum, which may be used by small companies. For this was done the recycling of gypsum and laboratory tests carried out to characterize: the powder, the mass unit and the fineness modulus, pastes, for the start and end times of the handle, the compressive strength, hardness, water absorption and corportamento material with the incorporation of additives, and the lining plates on the flexural strength, thickness and the density of the final product. Were also carried out tests on the powder, pastes and the lining plates made with natural gypsum, as a way to set a standard for comparison of results. The plaster used in this study is of natural origin, but it can also be obtained in industrial processes too. The plaster, when hydrated and used in the manufacture of plates, picture frames and statues, reproduces the characteristics of the rock where it originated. Thus recycling of gypsum residue was done observing the same steps used for producing gypsum which consists in milling, calcining and pulverizing. The recycling of gypsum, and reduce environmental liability and promote the sustainability of the sector, can contribute to the development of a new economic activity and produce social gains in the process. In the research it was found that it is technically feasible the production of lining plates with the use of recycled gypsum, even in small businesses. The recycled gypsum, as observed in this work, has characteristics compatible with those of natural gypsum. For small businesses, however, the best use of recycled gypsum is mixed into pastes, for the use of the material in the pure state requires adjustments and adaptations in equipment and manufacturing techniques.