Direct Fired Heating in Cement Industry
Originally created in the 1840s, cement has become keystone product in our society today- it is used to build sidewalks, buildings, streets, parking lots, houses, and much more. Cement production can be done one of three ways: dry, semi-dry or wet processing of various ores to produce a mixture of minerals.
Regardless of whether the ores are dry or wet, the process is as follows:
- Quarry the shale, limestone, silica and iron oxides.
- Crush and mix the minerals.
- Run the mixture through a rotary kiln. The picture below illustrates this step in the wet process. If the material is dry, the feed is first preheated before being discharged into the rotary kiln.
As the image shows, the wet material is being fed into a rotary kiln. The kiln is heated via a direct gas-fired combustion system to a temperature high enough to burn off the CO2, or “calcine” the limestone, forming clinker. After the clinker is produced, is then discharged.
4. The clinker is placed in a grinder and mixed with gypsum to produce Portland Cement.
5. The Portland cement mixture is bagged for sale.
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