cement raw material homogenization in dome yard

What Is Cement Raw Meal

Cement raw meal is the raw material for producing cement clinker, which is prepared in a certain proportion after crushing and grinding. After being calcined in a rotary kiln, the raw meal is turned into the clinker.

cement raw meal in pre homogenization yard
Raw meal in the stackyard

The composition and shape of the raw meal may vary according to different cement production methods. For example, in the dry process of cement production, the raw meal is ground into powders, while in other cement production methods, slurry, spherical, and massive raw meals are also commonly seen.

However, no matter what form the raw meal is, its chemical composition must be stable, and its fineness and moisture must meet the requirements of clinker calcination. Poor raw meal quality is harmful to the rotary kiln, and results in decreased product clinker.

Raw Meal Homogenization

How to maintain the quality of raw meal stable at a high level in the cement making process? The answer is homogenization.

Raw meal homogenization is a process in which the ingredients of the ground raw meal tend to be uniform through reasonable matching or pneumatic mixing. The raw meal preparation process of the cement industry includes four links: mining, pre-homogenization, grinding, and homogenization, which form the homogenization chain of raw meal preparation.

The prehomogenization yard in a cement plant
Pre homogenization yard under construction

Raw meal homogenization is the most important process link of the four, accounting for 40% of the homogenization task. It is an important factor to support the balanced and stable working performance of preheaters and kilns, and plays an important role in improving the output and quality of cement clinker.

Since the birth of suspension preheating and pre decomposition technology, the homogenization chain in cement dry production has been continuously improved, which has promoted the development and large-scale production of new dry cement, making it surpass the wet cement production technology and become the best cement production method.

How Does Homogenization Work

Now that we have learned the importance of raw meal homogenization in the cement industry, it is time to further explain its actual process, to answer the question: how exactly does homogenization make raw meal uniform.

The facility necessary for realizing raw meal homogenization is called homogenization silo or blending silo, in which the process of raw meal homogenization is completed. Nowadays, there are many kinds of homogenization silos in the cement industry. Different kinds of homogenization silos have different working methods. Due to space constraints, it is hard to cover them all comprehensively. However, they all follow the same basic principle:

The principle of raw meal homogenization is mainly to use the funnel effect produced by air mixing and gravity to mix the raw meal powder with as many multi layer material surfaces as possible when it falls down. Meanwhile, under the action of different fluidizing air, the fluidizing expansion of different sizes occurs along the parallel material surface in the silo. Some areas are unloaded and some areas are fluidized, so that the material surface in the silo is radially inclined to radial mixing and homogenization.

The Development of Raw Meal Homogenization

Raw meal homogenization technology has been constantly developing and improving since its birth, supporting the innovation of the cement production process.

Before the 1950s, raw meal homogenization mainly relied on mechanical mixing, which has high power consumption and a poor homogenization effect. Under such technical conditions at that time, the raw slurry was easier to mix than raw meal powder, so wet cement production was actively developed.

In the early 1950s, the batch air blending silo began to develop rapidly; In the 1960s, a double-layer silo was invented, in which the upper layer was used for blending and the lower layer for storage; In the 1970s, the Germans developed continuous homogenization silo and multi-material flow homogenization silo, which quickly became the mainstream in the cement plant. Up to now, on the basis of these two homogenization silos, people have expanded a variety of silo types, such as IBAU silo, CF silo, MF silo, TP silo, CP silo, and so on.

batch type homogenization silo design
The design of a type of batch homogenization silo

At present, the raw meal homogenization silo used in the cement industry is generally multi-material flow silo, because this homogenization silo can not only ensure a good homogenization effect but also save power consumption. Although the previously commonly used batch homogenization silo has a better homogenization effect, it consumes a lot of power and is multi silo intermittent operation, so it has been gradually eliminated.

In addition, while trying to weaken air mixing to save power consumption, many multi-material flow silos are also equipped with discharge silos with different volumes, so that the raw meal homogenized by funnel flow and radial mixing flow in the silo can be discharged into the warehouse or the silo under the main silo, and the materials entering the silo can be air stirred for a better homogenization effect.

AGICO Raw Meal Equipment

We are AGICO, a professional cement equipment supplier based in China. Our business services cover the design and construction of complete cement production lines as well as the procurement of single machines.

We have the ability to supply several types of machines that are needed for producing cement raw meal, including crushers, blending silos, bucket wheel stacker reclaimers, etc. Feel free to drop us a mail if you are in need of a cement machine.

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