Flota？？o do carv？o contido em um rejeito carbonoso

the processes involved in coal preparation produce harmful effects for the environment, mainly by the quantity and nature of wastes that are generated. these tailings generally called “pyritic”, even though not presenting a high pyrite content, are an acid material harmful to the environment. these tailings are usually disposed of in tailings dams. the tailings, studied in this work come from a process involving dense-medium cyclones and spirals. they have an ash content of 56% and a calorific value of 5,800 btu / lb, the sulfur content is 1.2%. in terms of size, the material is considered as ultrafine, as 63% of it is less than 0,014 mm. the coal matter content of these tailings is easily recovered by froth flotation, as evidenced in this work. it's possible to recover 74% of the coal matter and to obtain a product with 7.3% ash and calorific value of 14,225 btu / lb in dry basis.