초록 ▼

Pulverized mineral material is calcined by suspending it in a current of gas constituted by a combustive gas and a fuel whose combustion furnishes the necessary calories for the calcination. To enable solid fuels rich in ash, substantially inert and difficult to condition to be used, the fuel is gas

Pulverized mineral material is calcined by suspending it in a current of gas constituted by a combustive gas and a fuel whose combustion furnishes the necessary calories for the calcination. To enable solid fuels rich in ash, substantially inert and difficult to condition to be used, the fuel is gasified in a fluidized bed hearth by blowing air from below through the bed whereby a gaseous fuel is disengaged from the bed and flows upwardly with the very finest particles of the solid fuel suspended therein. This is mixed with air and the mineral material to calcine the same.

대표청구항 ▼

A process for the calcination of a pulverized mineral material, which comprises the steps of (a) gasifying pieces of a solid fuel in a fluidized bed hearth wherein the fluidized bed is maintained at a depth decreasing progressively from a first zone whereto the solid fuel is delivered to a second zo

A process for the calcination of a pulverized mineral material, which comprises the steps of (a) gasifying pieces of a solid fuel in a fluidized bed hearth wherein the fluidized bed is maintained at a depth decreasing progressively from a first zone whereto the solid fuel is delivered to a second zone wherefrom residual ashes are removed by blowing air from below through the fluidized bed hearth and the air is blown through the fluidized bed at a speed decreasing from the first to the second zone until the solid fueld has been gasified and is disengaged from the fluidized bed hearth in an upwardly moving flow of gaseous fuel entraining the very finest solid fuel particles in suspension therein, (b) selecting the granulometry of the solid fuel particles so that the particles entrained with the gaseous fuel out of the fluidized bed hearth constitute about 20% to 50% of the fuel mass, (c) guiding the flow of gaseous fuel and the fuel particles suspended therein upwardly through a substantially vertical conduit at a speed of ascension in excess of 20 meters/second to a separate calcination chamber, and burning the gaseous fuel and the fuel particles in the separate calcination chamber, and (d) mixing air and the pulverized mineral material with said flow of gaseous fuel to burn the gaseous fuel and the solid fuel particles suspended therein until the burned fuel furnishes the required calories for the calcination.