Drying minerals with a “heavy-duty” Tema Fluid Bed dryer.
In the first stage of drying, free (surface) moisture is removed from the product and all available energy supplied as heat (gas burner) in the drying air is used for evaporation.
The temperature of the air moving through the fluidized bed drops as it absorbs moisture up to its saturation point. If there is a change in the moisture content of the feed or in the feed rate, the temperature of the air supply is adjusted to maintain a steady product temperature at the exit point of the dryer section.
Direct burners (up to 600 °C) are used and may be fired by natural gas, light fuel oil, propane or heavy fuel oil. Conveying of the granular product is achieved by the use of a low-frequency, high-amplitude shaker mechanism. For de-dusting of the air, automatically self-cleaning Puls-Jet filter installations are used.
The filter dust is usually dry and can therefore, be discharged through a rotary valve, transported to the product outlet by a screw conveyor and mixed with the end product.
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