Otimização das condições experimentais na desidratação da gipsita para obtenção de um gesso reciclável

Abstract

Optimized operational conditions for recycled beta plaster production had been determined with aid of pressure and temperature controls of gypsum ore dehydration process. Plaster currently does not possess, officially, recognized techniques of recycling or reuse. For identification of the quality of recycled plaster the properties had been tested: hardness, unit mass and flexion strength module. An experimental design of 32 type was adopted, with the generated results being studied with aid of the response surfaces method. A mathematical model of the quadratic type was adjusted well to the experimental data, allowing an unquestionable visualization of the process optimized conditions. Photographs of the microstructure of the produced plaster, obtained in a scanning electronic microscopy, with factor of magnifying of the order of 3700 times, had shown the crystal formation prolongated and responsible for a microstructure that guarantees similar properties or better that of the microstructure of origin for formed plasters and hydrated. The projection of the levels curves in the contours diagram showed to one very small interaction between the studied factors. The region of excellent conditions was identified around 0,6 manometric atmosphere and 170°C