Gypsum, calcium sulfate dihydrate (CaSO4.2H2O) found in Polo Plasterer Araripe, Pernambuco, Brazil, is considered the best quality in the world, with purity content ranging from 88% to 98% containing 79% sulfate calcium and 21% water of crystallization. When dried until the loss of 1.5 water molecules, constitutes a stable hemihydrate, called plaster, whose features are the ability to rehydrate with exothermic reaction, the phenomenon handle and return to the crystal structure. Polo provides 95% of the plaster consumed in Brazil. The reserves are estimated at 1.2 billion tons, the world's fifth volume. Ovens Pole can be direct or indirect contact between the flue gas and ore, and the type of operation, batch or continuous. In the indirect gas heat a metallic surface that transfers the heat using fuel or bunker oil, since the contact thereof with the gypsum is not recommended and mixture of the material may occur, resulting in alteration of properties of the plaster. In direct, the gas flows inside a metal cylinder, allowing more efficient heat exchange. The use of natural gas has advantages such as heat exchange efficiency and higher volume processing and preservation of the ecosystem, being low-polluting. Its combustion is clean, free of soot and other materials that can harm the environment with low levels of nitrogen, carbon dioxide, water and sulfur compounds. Natural gas reached Araripe in March 2011, a pilot experiment, with the expectation of a jump in quality and volume on local production. Cleaner and more efficient, can provide energy security required for the sector to better meet growing demand, avoiding deforestation in the region that uses wood as fuel.
gypsum; natural gas; deforestation; ovens direct contact; environmental preservation; polo plasterer
