Direct Fired Heating in Cement Industry

Direct Fired Heating in Cement Industry

Originally created in the 1840s, cement has become a 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.

The Manufacturing Process

Regardless of whether the ores are dry or wet, the process is as follows:

  1. Quarry the shale, limestone, silica and iron oxides.
  2. Crush and mix the minerals.
  3. Run the mixture through a rotary kiln. The picture below illustrates this step in the wet process. If the material is dry, it is first preheated.

Wet Process Cement Manufacturing

As the image shows, the wet material is being fed into a rotary kiln. The kiln is heated via a direct fired process air heater to over 2000 degrees Fahrenheit to burn off the CO2. This “calcines” the limestone, forming clinker. After the clinker is produced, the product is then discharged.

4. The clinker is placed in a grinder and mixed with gypsum to produce cement.

5. The cement mixture is bagged for sale.


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