Patent ID: 6375456
Filing Date: 2002-04-23
Classification: F27B

Abstract:
A process for calcining an ore-based material, comprising the steps of:producing a flame with at least one fuel and at least one oxidizer, the flame comprising a primary combustion zone formed by the combustion of a first fuel and a first oxidizer, the primary combustion zone located adjacent to the points of injection of the first oxidizer and of the first fuel, and a secondary combustion zone formed by the combustion of a second fuel and a second oxidizer, the secondary combustion zone located downstream of the primary zone; preheating the second fuel by flowing the second fuel through the primary zone of the flame; and heating said material by contact with a heat source created by the flame; wherein the step of preheating the second fuel comprises flowing the second fuel along a distance with the second fuel in contact with the flame in the primary zone for at least some of the second fuel to be preheated to a temperature of at least 400Â° C.