As we all know, there are two elements to affect the quality and efficiency of the cement production line: cement production process and cement equipment. Cement equipment refers to all equipment in the cement plant, such as cement mill, cement crusher, cement kiln, cement silo, cement preheater, etc. Today we will focus on the cement production process analytics.
What is the cement production process? The cement production process is also called the cement manufacturing process, cement making process, directly decide the cement equipment of cement production line, and investment and production scale.
In general, a full cement production process includes the cement crushing process, raw mill process, clinker process, and cement grinding process, cement packing process, and related process.
The Portland cement manufacturing process is representative of all types of cement. limestone and clay are the main raw materials of cement making, the cement raw materials will be processed into a raw meal by crushing, batching, grinding. Feeding raw meal into cement kiln to make clinker, the clinker, and some mixed materials will be ground together by cement grinding plant, the finished cement will be done.
- Cement raw material preparation: Limestone is main raw materials for cement manufacturing, and most cement plants are located next to the quarry to reduce the transportation cost; Using explosion or getter loader to mine raw materials; sending raw materials to the cement crusher to crush or hammer; crushed raw materials are stored to prevent from environment and dusting.
- Raw meal: In the raw meal working site, the raw materials are processed by the raw mill to ensure the high-quality mixing; cement ball mill and cement vertical mill are generally used in the raw meal process; the finished raw meal are finally sent to the stacker and reclaimer for storage and further mixing.
- Clinker production: The diameter of the clinker ball must between 0.32 and 5.0cm. There are three steps of the high-temperature system: Drying or preheating, calcining, and sintering. The calcining is the core part of the clinker production; the raw meal is weighed and sent into preheater and cement kiln to process clinker. Grate cooler helps to cooler clinker, the cooled clinker is sent to the cement silo for storage. After cooling, the clinker can be transported on the conveyor belt and can regenerate up to 30% of its heat. Cooling air from the clinker is fed into the rotary kiln, which is conducive to fuel combustion. Clinker storage capacity can be based on the market, and a cement plant usually stores 5-25% of the annual clinker production.
- Cement grinding: The clinker is taken from the clinker silo and sent to the feed bin where it is mixed with gypsum and additives before entering the cement grinding plant. In the cement grinding process, the clinker is ground to a fine powder along with other materials, up to 5% gypsum or additional anhydrite is added to control the solidification time of the cement, and other compounds are added, such as compounds used to regulate fluidity or gas content.
- Cement packing and shipping: Finished cement will be stored in the cement silo, and the cement packing plant will help to bag it as requested. Cement can be delivered in bulk to the customer in trucks or wagons, or bagged and delivered in standard lorries.
Types of cement production process
As for the cement production process types, based on different raw meal production processing, we can divide the cement production process into dry process of cement (include Semi-dry process of cement) and wet process of cement ( include Semi-wet process of cement).
Dry process of cement
There are two methods to choose, drying and grinding the cement raw materials at the same time; or dry cement raw materials firstly, then grind them into raw meal. The raw meal will be sent into cement kiln to calcine clinker.
The semi-dry process of cement also belongs to the dry process of cement, add certain water into raw meal powder to make raw meal ball, which will be sent into the vertical kiln to process cement clinker.
The main advantage of dry process cement production is low heat consumption, it’s advantages include nonuniformity of raw meal, dusting, high power consumption.
Wet process of cement
The proportioned raw materials and water are ground into cement raw slurry, and sent into wet process kiln to calcine clinker.
The semi-wet process of dehydrating raw slurry, making raw meal block, and then calcining in the kiln can also be classified as wet-process cement production. Drying and grinding dehydrated raw materials and send them into precalciner, this process is generally known as wet grinding dry burning.
It has advantages of easy to homogenize raw meal, uniform composition, high and stable quality of clinker, low power consumption, less dust. The disadvantages include high energy consumption of the clinker, low production efficiency, and it tends to be replaced by a new dry process cement production.