Method and kiln for calcining finely divided material
AssigneeVeitscher Magnesitwerke-Aktiengesellschaft
InventorsMichael Grill, Helmut Grohmann
Life of this patent
Estimating the term…
Abstract
An aqueous solution of magnesium chloride is sprayed into a kiln chamber where it is countercurrently heat treated by a stream of hot gas produced by flames projected into the chamber by burners. Calcined material is removed from the bottom of the kiln chamber and the hot gas stream and any treated material carried thereby is removed from the top of the chamber. Material carried by the hot gas stream is separated therefrom in a cyclone separator and the separated material is returned to the kiln chamber through a zone heated to a temperature in the range of the temperature in the kiln chamber.
Claims16
In a method of heat treating finely divided material, wherein the material is introduced into a treatment chamber at a first inlet zone and is subjected to a treatment temperature in the treatment chamber, a stream of hot gas is passed into and through the chamber to produce said temperature, completely heat treated material is removed from the chamber through one outlet, the hot gas stream carries along some of the material not completely heat treated, the gas stream with the incompletely heat treated material is removed from the chamber through another outlet, the incompletely heat treated material carried by the hot gas stream is separated therefrom after removal from the chamber, and returning the separated material to the treatment chamber at a second inlet zone spaced from the first inlet zone:
- the step of returning the separated material through a confined zone heated to a temperature in the range of the treatment temperature.
In a kiln for heat treating finely divided material which defines a treatment chamber and comprises a first inlet means for delivering the finely divided material into the treatment chamber, main burner means extending into the chamber at a level spaced from and below the first inlet means to produce a stream of hot gas passing into and through the chamber, an outlet spaced from and below the main burner means for removing completely heat treated material from the kiln chamber, another outlet spaced from and above the first inlet means for removing the hot gas stream and not completely heat treated material carried thereby, means for separating the incompletely heat treated material carried by the hot gas stream therefrom outside the kiln chamber, and at least one conduit receiving the separated material and returning the same to the kiln chamber in the region of the main burner means:
- means for heating at least a part of the return conduit to a temperature in the range of the treatment temperature.
Dependencies are inferred from the claim text.