Process and apparatus for calcining gypsum
AssigneeFuller Company
InventorSidney M. Cohen
Life of this patent
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Abstract
An apparatus and process for calcining gypsum is disclosed which utilizes a flash furnace for rapidly calcining fine particulate gypsum while the material is suspended in a stream of hot gas. The method and apparatus utilize a two-stage suspension preheater for utilizing waste gases from the calcining furnace for preheating raw material to be calcined and a two-stage suspension cooler for cooling hot calcined gypsum which is discharged from the calcining furnace. Spent cooling gas is supplied to the preheater for use in preheating the fresh gypsum to be calcined. The invention also contemplates recirculating a portion of the gypsum discharged from the furnace back to the furnace for further calcination. Hot product may be discharged directly from the furnace.
Claims7
A process for calcining gypsum comprising the steps of:
- providing a furnace means for calcining gypsum;
- supplying hot gas and gypsum to be calcined to the furnace means whereby the hot gas at least partially calcines the gypsum within the furnace means while the gypsum is suspended in the hot gas;
- discharging at least partially calcined gypsum from the furnace means;
- separately discharging hot gas from said furnace means;
- cooling at least a portion of the at least partially calcined gypsum discharged from the furnace by suspending the calcined gypsum in cooling gas whereby the cooling gas is heated and the calcined gypsum is cooled;
- preheating fresh gypsum to be calcined by suspending the fresh gypsum in hot gas discharged from the furnace means and the heated cooling gas;
- and
- selectively recirculating to the furnace means a portion of the at least partially calcined gypsum discharged from the furnace means for further calcining.
Dependencies are inferred from the claim text.