Visit a cement factory . See how cement is prepared and discuss the process.
Answers
Cement is typically made from limestone and clay or shale. These raw materials are extracted from the quarry crushed to a very fine powder and then blended in the correct proportions.
This blended raw material is called the 'raw feed' or 'kiln feed' and is heated in a rotary kiln where it reaches a temperature of about 1400 C to 1500 C. In its simplest form, the rotary kiln is a tube up to 200 metres long and perhaps 6 metres in diameter, with a long flame at one end. The raw feed enters the kiln at the cool end and gradually passes down to the hot end, then falls out of the kiln and cools down.
The material formed in the kiln is described as 'clinker' and is typically composed of rounded nodules between 1mm and 25mm across.
After cooling, the clinker may be stored temporarily in a clinker store, or it may pass directly to the cement mill.
The cement mill grinds the clinker to a fine powder. A small amount of gypsum - a form of calcium sulfate - is normally ground up with the clinker. The gypsum controls the setting properties of the cement when water is added.
Work in cement plant is a bit tough, because of the following reasons:
- Heavy maintenance of plant equipments requires you to be super busy all the time.
- In case of improper dust collection in older/cheaper plants, there is a lot of dust at Crusher/Mill areas, so you'll have breathing problems. (A lot of accounts where cement entered into my mouth)
- Most of the plants are located in limestone belts in India which are far off from cities, and you're stuck in a remote location with no entertainment opportunities.
- There is not much engineering application when it comes to running a cement plant.
- It's the easiest industry to get in due to the nature of applications. Crush it, mix it, cook it, cool it, and grind it. Lalala, you have cement.
- The nature of work is hazardous, so you have to follow safety regulations all the time if you want to stay safe.
- Compensation is not really good (unless you're in an MNC like LafargeHolcim
The raw materials needed to produce cement are generally extracted from limestone rock, chalk, clayey schist or clay.They are then crushed and transported to the plant where they are stored and homogenized.The raw material is preheated and then sent to the kiln. The material is heated to 1,500°C before being suddenly and dramatically cooled by bursts of air. This produces clinker, the basic material required for the production of all cements.
in short
Cement manufacturing is a complex process that brings with mining and then grinding raw materials that include limestone and clay, to a fine powder, called raw meal,which is then heated to a sintering temperature as high as 1450 degree celcious in a cement..