Concrete is one of the important building materials in the modern construction industry. It is manufactured after the mixing of cement, water, sand, and some other admixtures. Of them, cement is the most indispensable raw material. It is usually composed of limestone, clay, slate, blast furnace slag, iron ore, etc (different admixtures gives cement different properties). All these ingredients combined to form a hard substance by heating with a high temperature and then they can be ground into what we usually think of as a fine cement powder.
As a full-range supplier for cement equipment in the cement manufacturing plant, AGICO has mastered the advanced production technology and the ability to produce large-scale mechanical equipment from individual machines to complete plants. We provide various types of cement EPC projects and one-stop services for customers according to their requirements. To keep up with the changing situation of the industry, we have been strengthening the cement plant technology innovation, which not only ensures the environmentally sustainable development but also guarantees the health and safety of workers’ working environment.
Raw Material In Cement Manufacturing Process
|Main Materials||Calcareous materials||Limestone,chalk,shells,marl,calcium carbide slag,marble,etc.|
|Clayey materials||Clay,loess,shale,phyllite,river mud,fly ash,|
|Corrective Materials||Iron corrective materials||Pyrite cinder,iron ore,copper slag,etc.|
|Siliceous corrective materials||Sandstone,siltstone,diatomaceous earth,etc.|
|Aluminum corrective materials||Furnace slag,coal gangue,bauxite,etc.|
|Set-retarded Material||Gypsum,anhydrite,phosphogypsum,industrial by-product gypsum,etc.|
|Cement Mixture||Granulated blast-furnace slag,limestone,etc.|
Calcareous Materials & Clayey Materials
The basic raw materials of cement manufacturing are calcareous material (CaO) and clayey material (SiO2, Al2O3, and a little Fe2O3). In the raw materials used to produce 1 tone clinker, the calcareous material accounts for about 80%, and the clayey material accounts for 10%~15%.
In the cement industry, calcareous materials refer to materials that regard calcium carbonate as the main component. It can be divided into natural and artificial (i.e., industrial wastes, like slag). The natural ore containing CaCO3 is the commonly used calcareous material in cement production, such as limestone, marl, chalk, marble, etc.
Clayey materials are the general term of raw materials containing water aluminosilicate. The natural clayey materials used in the cement industry include clay, loess, shale, mudstone, siltstone, and river mud. Fly ash is a kind of recycled and reprocessed material which can replace clay to save production costs
Corrective materials are used in small quantities only to adjust the chemical composition of the cement raw meal to meet the required quality targets. If an essential chemical component needed in the cement raw meal is not present in the required amount, corrective materials are used as additives. Generally, they can be classified into iron corrective materials, siliceous corrective materials, and aluminum corrective materials.
Gypsum (calcium sulfate dehydrate) is the most commonly adopted set-retarded material in cement manufacturing plants. It is generally added in a very small amount before the clinker is sent into a cement mill. Its main function is to prolong the setting time of cement otherwise the cement would set within minutes after mixing with water.
Except for the four materials we mentioned above, another important raw material is coal. It acts as the energy source in the cement manufacturing process. After mined, it should be further processed in the coal mill for more efficient burning.
Fly Ash & Slag
Fly ash is the powdery ash after coal combustion in thermal power plants, and the slag is also formed after coal combustion in industrial boilers. Their main components are SiO2 and Al203 and usually used in the cement manufacturing process for partially or completely replacing clay to participate in material batching, or used as aluminum corrective materials and cement mixture.
How To Manufacture Cement?
At present, the cement manufacturing processes can be divided into dry process and wet process. Their main difference is that in the dry process, raw meals are fed into the cement kiln in a dry state. While in the wet process, the raw meals are mixed with water in a slurry state. Regardless of the method used, the first stage of cement manufacturing is always started from raw materials quarrying.
In the cement manufacturing process, the calcareous material and clayey material, as the basic raw material, will be excavated from open-pit mines near the cement plant after drilling and blasting. Then they will be fed into a crusher in the quarry, the product of which will be further transported to the cement plant, or they will be delivered to a crushing plant by trucks for further reduction in size. This depends on the raw materials particle size, economic factors, and the actual situation on the quarry.
After different kinds of raw materials are mined, they will get into a crushing stage. Cement crushers, we usually set the primary and secondary crushers, are the main equipment applied to crush raw materials until reaching an appropriate particle size, such as cone crusher, jaw crusher, hammer crusher, and roller crusher. Then the crushed materials are sent in a dryer for removing uncombined water. This step is typical of the dry method cement production process.
The pre-proportioning of raw materials is mainly finished in pre-blending yards. Crushed limestones are pre-blended and layered stacking on a circular pre-blend yard by stacker, and other addictive materials are on the longitudinal yard. Then a re-claimer will deliver them to their respective storage bins.
Raw meal grinding is a key part of the raw material preparation process. Varies types of cement raw mills are the main helper in this stage. The amount of each material received by the raw mill depends on the speed of belt conveyors which take the materials from their respective storage bin and feed them into the raw mill. After that, they will be ground into fine size. While, in the wet process, crushed raw meals are sent in wet grinding mills where a lot of water is added, these get ground to a fine, thin paste.
Homogenizing silo is a device used to mix raw meals by compressed air to get uniform chemical composition and fineness. It is the last homogenizing step in the line of the raw meal preparation processes. Besides, it also has the function of storage.
In the clinker calcination process, raw meals will be first sent into a preheater which is a device that reuses the hot gas discharged from kiln tail and calciner to preheat raw meals so that they can be partially calcined before entering the cement kiln. The preheater replaces partial functions of cement kiln, reduces the energy consumption and cost.
However, clinker burning still mainly occurs in the cement kiln, in which raw materials can be heated to 1500℃. In the heating process, the chemical interaction between raw meals will eventually lead to the formation of many gray spherical substances which we called clinker. These gray spherical substances are discharged with high temperature, so they should cool down to normal temperature by a cooler set behind the kiln.
After cooling, the ball shape clinker will be mixed with addictive materials, such as gypsum, limestone, etc., and then ground by cement mill. The final cement products are transferred to silos for storage and extracted by using a bucket elevator to be packed. Now, they are ready to be transported to various locations.
EPC Projects Of Cement Manufacturing Plant We Offer
For different stages in the cement manufacturing process, AGICO offers various EPC projects of cement manufacturing plants: cement production lines, stone crushing plants, cement grinding units, and fly ash processing plants. All of these EPC projects can highly meet your needs for cement production with superior quality.
What Is EPC Project?
EPC refers to Engineering, Procurement, and Construction, which is an international general term of the general contracting projects. The EPC project service means that the project contracting enterprise shall be responsible for all stages of project construction, such as engineering design, equipment procurement, construction, commissioning, etc., according to the fixed or adjustable total price specified in the contract, and undertake the due obligations of quality, progress, cost and safety aspects of the project, finally submit a project meeting the use function and conditions to the owner.
In the cement industry, with the continuous technology upgrading and the intensification of market competition, more and more customers have turned their attention to EPC turnkey projects. One of the reasons is that the EPC project is more suitable for large projects with the engineering process as the main core. In addition, what are the other advantages of the EPC turnkey project compared with the traditional management model?
Low & Fix Cost
Centralized bidding reduces transaction costs, and in the project construction process, comprehensive management of the design, procurement, and construction also reduces the cost of the enterprise. In addition, it adopts a fixed-price contract which prevents contractors from adjusting prices because of changes in costs.
Clearly Defined Rights & Responsibilities
The EPC project management mode has a clear division of responsibilities, which reduces the risk of project loss or project failure caused by a conflict of interest. The owner is mainly responsible for the design, technical standards and the supervision of the contractor in the construction process, which bears little risk and is conducive to the project quality management, progress monitoring, and cost control.
High Efficiency & Profit
When we adopt the EPC project, the project design, equipment procurement, engineering construction, and other links can be all cross-implementation by the contracting enterprises, so as to effectively reduce the construction period and improve the profit.
Why Choose AGICO Cement EPC Project?
AGICO is a professional cement equipment and cement manufacturing plant supplier in China. We have more than 20 years’ experience in constructing cement EPC projects at home and aboard, which covers cement manufacturing plant design and construction, cement equipment production, installation, commissioning, and maintenance, personal training, and other services.
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