The Gypsum Kiln Overview from Mr Oscar Goudriaan, Managing Director of OMV (Pty) Ltd
During manufacturing gypsum for various market requirements a significant stage of the cycle is the drying process. Wet gypsum is conveyed from the plant onto the primary stockpile, this gypsum is either dried using the drying floors or more recently by using the drying kiln. This process of eliminating natural drying decreases the drying time and in turn allows for a higher production output. The drying capacity of the rotary convection dryer is to reduce moisture from a free moisture content of 20-25% to a moisture content of below 10%, at a feed rate of 50 tons per hour.
At a free moisture content of roughly 20-25% the gypsum fed into the kiln. This product is still identified as wet and is not suitable to fit the requirements of the clients.
The dryer consists of two main parts, the combustion chamber and the rotary drum. Within the combustion chamber an oil burner is used to heat air which is sucked through holes in the back plate into the chamber. This air is heated to +- 850 degrees C. The air from the combustion chamber is forced into the drum which rotates at 4 RPM.
Gypsum is fed into the feed bin by means of front end loader. This material is then conveyed into the feed chute which deposits the material into the rotary drum.
Free moisture is removed from the gypsum by means of absorption of moisture by the passing heated air. The heated air which passes through the gypsum naturally removes the moisture on the external area of the gypsum's particles. The extraction fan sucks the air into the stack through a cyclone that eliminates airborne particles.
The final product is suitable for the requirements of OMV's various clients is then discharged by means of a conveyor to the dispatch floor from the discharge opening of the kiln. This product is ready to be used in various applications throughout the different sectors for which OMV caters.