What Is a Clinker Brick?

Clinker refers to clay, pre-fired ceramic materials such as ceramic powder, brick powder, or pre-fired clay. Gypsum is generally added to the molding material formula to increase strength, and fresh, unfired clay powder is added to increase viscosity when not dry, reduce shrinkage and increase hardness when fired, and can also create interesting surface texture effects. It is also used in the manufacture of crucibles and other products to enable extreme high temperature resistance.

Clinker is a necessary step in the cement production process, and its production process is also very complicated. It is roughly divided into five steps: crushing and pre-homogenization, raw material preparation, raw material homogenization, pre-heat decomposition and clinker burning. to make. Among them, crushing and pre-homogenization include: crushing and pre-homogenization of raw materials.

Clinker crushing and pre-homogenization

During cement production, most raw materials are crushed, such as limestone, clay, iron ore, and coal. Limestone is the raw material that produces the largest amount of cement. After mining, the particle size is larger and the hardness is higher. Therefore, the crushing of limestone occupies a relatively important position in the crushing of the materials in the cement plant.

The crushing process is more economical and convenient than the grinding process. It is very important to choose crushing equipment and grinding equipment reasonably. Before the material enters the grinding equipment, as much as possible, crush large pieces of material to a small, uniform size to reduce the load on the grinding equipment and increase the output of the honing machine. After the material is broken, the phenomenon of separation of different granularity materials during transportation and storage can be reduced, and raw materials with uniform composition can be obtained to improve the accuracy of batching. The pre-homogenization technology is to use the scientific stacking and reclaiming technology during the storage and retrieval of raw materials to achieve the initial homogenization of the raw materials, so that the raw material storage yard has the functions of storage and homogenization. The basic principle of raw material pre-homogenization is that when the materials are stacked, the incoming materials are continuously stacked by the stocker into a certain number of layers that are parallel to each other, overlap each other, and have the same thickness. When taking the material, in a direction perpendicular to the material layer, cut all the material layers at the same time as far as possible, and cut them in turn until they are finished, that is, tiling straight.

Clinker raw material preparation

The preparation of raw meal is the process of feeding limestone, clay and calibration raw materials into the raw meal mill in proportion to grind the raw meal. Most of the raw mills of new dry cement production lines are vertical mills.

The working principle of the vertical mill: the motor drives the grinding disc to rotate through a reduction gear, and the material falls to the center of the grinding disc through the feeding lock device through the feeding lock device. The crushed material overflows from the edge of the grinding disc and is dried by the high-speed upward hot air flow from the nozzle. Depending on the air velocity, part of the material is taken by the air flow into the high-efficiency powder separator. , Re-grind; fine powder is ground out with the air flow and collected in the system dust collection device, which is the product. The coarse particles that are not carried by the hot air flow are fed into the powder separator by the bucket elevator after being circulated out of the grinding plate.

Clinker raw material homogenization

In the new dry cement production process, the stability of the raw material composition in the pit is the prerequisite for the stable clinker firing thermal system. The raw material homogenization system plays the final role of stabilizing the raw material composition in the pit. The principle of homogenization uses air stirring and gravity to produce a "funnel effect", so that when the raw meal powder is discharged downward, it is possible to cut the multi-layered material surface as much as possible to fully mix. Different fluidized air is used to cause different sizes of fluidized expansion of the parallel material surface in the warehouse. Some areas are unloaded and some areas are fluidized, so that the material surface in the warehouse is inclined to perform radial mixing and homogenization.

Clinker preheat decomposition

The preheater and partial decomposition of the raw material are completed by the preheater, which replaces some functions of the rotary kiln to shorten the length of the return kiln. At the same time, the kiln is stacked for gas-material heat exchange process and moved to the preheater in suspension The next step is to make the raw material fully mix with the hot gas discharged from the kiln, increase the contact area of the gas material, fast heat transfer speed, high heat exchange efficiency, and achieve the improvement of kiln system production efficiency and reduction of clinker burning heat consumption. purpose.

Clinker clinker

After the raw materials are preheated and decomposed in the cyclone preheater, the next step is to enter the rotary kiln for firing the clinker.

In the rotary kiln, the carbonate is further rapidly decomposed and a series of solid-phase reactions occur to generate minerals in the cement clinker. As the temperature of the material rises, the mineral will change into a liquid phase, and it will dissolve in the liquid phase and react to form a large amount (clinker). After the clinker is fired, the temperature starts to decrease. Finally, the high temperature clinker discharged from the rotary kiln is cooled by the cement clinker cooler to a temperature that can be endured by downstream conveying, storage and cement mills, and the sensible heat of the high temperature clinker is recovered, improving the thermal efficiency and clinker quality of the system. ^[2]