Cement kiln system for co-processing manganese slag to produce pozzolanic admixture

Abstract

The utility model discloses a system for producing a pozzolanic admixture by co-processing manganese slag in a cement kiln. The system comprises a raw material processing-homogenizing unit, a powder conveying-heat exchange decomposition unit, a calcining unit, a cooling unit, a waste gas processing unit, a storage unit and a combustion unit. The raw material treatment-homogenization unit is used for treating wastes such as manganese slag and sending the treated wastes to a raw material homogenization silo; the powder conveying-heat exchange decomposition unit conveys and decomposes powder; the calcining unit is used for calcining the hot raw material; the cooling unit is used for cooling the calcined mixed material; the waste gas treatment unit treats kiln head waste gas; the storage unit is used for storing mixed materials and kiln dust; and the combustion unit supplies heat to calcination. According to the system, resource utilization of wastes such as manganese slag is realized through collaborative operation of all units, and a volcanic ash mixed material is produced for cement production. Meanwhile, the waste gas is treated and discharged after reaching the standard, waste heat is recycled, the resource utilization rate is increased, environmental pollution is reduced, and remarkable economic and environmental benefits are achieved.

Description

A system for co-processing manganese slag in cement kilns to produce pozzolanic composite materials Technical Field

[0001] This utility model relates to the field of cement kiln technology, specifically to a system for co-processing manganese slag in cement kilns to produce pozzolanic composite materials. Background Technology

[0002] With industrial development, the disposal of waste such as manganese slag, polluted soil, and shale construction waste has become an urgent environmental problem. Manganese slag contains a certain amount of manganese and other heavy metals, and improper disposal can pollute soil and water bodies; pollutants in polluted soil can affect the balance of ecosystems and the safety of crops; and the indiscriminate dumping of shale construction waste also occupies a large amount of land resources.

[0003] At the same time, the cement industry requires a large amount of blended materials to improve cement performance and reduce production costs during the production process. The acquisition of traditional blended materials often relies on the extraction of natural resources, which not only exacerbates resource shortages but also damages the ecological environment.

[0004] Against this backdrop, it is crucial to find a technology that can effectively dispose of wastes such as manganese slag, contaminated soil, and shale from construction waste, while also providing high-quality admixtures for the cement industry. Cement kiln co-processing technology, with its high temperature and high efficiency, has become one of the effective ways to solve these problems. However, current technologies still have shortcomings in system integration, process optimization, and the efficiency of waste resource utilization. There is an urgent need to develop a new system for co-processing manganese slag in cement kilns to produce pozzolanic admixtures, in order to achieve the harmlessness, reduction, and resource utilization of waste. Summary of the Invention

[0005] The purpose of this utility model is to provide a system for co-processing manganese slag in cement kilns to produce pozzolanic composite materials, which solves the problem of disposing of waste such as manganese slag, polluted soil and construction waste shale in the existing technology, and overcomes the problem of excessive dependence on natural resources for obtaining composite materials in the cement industry, so as to achieve the harmlessness, reduction and resource utilization of waste.

[0006] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A cement kiln co-processing manganese slag to produce pozzolanic composite material, including a raw material processing-homogenization unit, a powder conveying-heat exchange and decomposition unit, a calcination unit, a cooling unit, a waste gas treatment unit, a storage unit and a combustion unit;

[0007] The raw material processing-homogenization unit is used to process manganese slag, contaminated soil and construction waste shale and then transport them to the raw material homogenization silo.

[0008] The powder conveying-heat exchange and decomposition unit is connected to the raw material homogenization silo, and the powder conveying-heat exchange and decomposition unit is used to convey and decompose pozzolanic powder.

[0009] The calcination unit is connected to the powder conveying-heat exchange and decomposition unit, and the calcination unit is used to calcine the hot raw materials;

[0010] The cooling unit is connected to the calcination unit, and the cooling unit is used to cool the calcined pozzolanic composite material.

[0011] The waste gas treatment unit is connected to the kiln head of the calcination unit, and the waste gas treatment unit is used to treat the waste gas from the kiln head.

[0012] The storage unit is connected to the cooling unit-exhaust gas treatment unit, and the storage unit is used to store pozzolanic composite material and kiln ash;

[0013] The combustion unit is connected to the calcination unit, and the combustion unit is used to provide heat for calcination.

[0014] As a preferred solution for a cement kiln co-processing manganese slag to produce pozzolanic composite materials, the powder conveying-heat exchange and decomposition unit includes a bucket elevator, a pneumatic three-way valve, an air conveying chute, a rotary unloader, an electro-hydraulic plug-in valve, and a preheating decomposition furnace system connected in sequence. The powder conveying-heat exchange and decomposition unit conveys the pozzolanic powder from the raw material homogenization silo and decomposes it through heat exchange in the preheating decomposition furnace system. The preheating decomposition furnace system does not inject fuel and only serves as a ventilation duct.

[0015] As a preferred embodiment of the cement kiln co-processing manganese slag to produce pozzolanic composite materials, the calcination unit includes a rotary kiln, which is connected to the preheating decomposition furnace system, and the rotary kiln calcines the hot raw materials after heat exchange decomposition.

[0016] As a preferred embodiment of the cement kiln co-processing manganese slag to produce pozzolanic composite material, the cooling unit includes a grate cooler and a cooling fan. The grate cooler is connected to the rotary kiln, and the cooling fan provides air to the grate cooler to cool the calcined pozzolanic composite material.

[0017] As a preferred solution for a cement kiln co-processing manganese slag to produce pozzolanic composite materials, the waste gas treatment unit includes a kiln head waste heat boiler, a bag filter, and a kiln head exhaust fan. The kiln head waste heat boiler is connected to the grate cooler to cool the kiln head waste gas. The bag filter is connected to the kiln head waste heat boiler for dust removal. The kiln head exhaust fan is connected to the bag filter to discharge the qualified waste gas into the atmosphere.

[0018] As a preferred embodiment of the cement kiln co-processing manganese slag to produce pozzolanic composite material, the storage unit includes a chain bucket conveyor connected to the grate cooler to transport the cooled pozzolanic composite material to the clinker silo for storage.

[0019] The storage unit also includes a chain conveyor, the feed end of which is connected to the kiln head waste heat boiler and the bag filter. The chain conveyor transports the collected kiln ash to the clinker silo for storage via the chain bucket conveyor.

[0020] As a preferred embodiment of the cement kiln co-processing manganese slag to produce pozzolanic composite materials, the combustion unit includes a kiln head burner, which is connected to the rotary kiln to inject pulverized coal into the rotary kiln for combustion to provide heat for the calcination of raw materials.

[0021] The beneficial effects of this utility model are as follows:

[0022] First, the raw material processing-homogenization unit transforms manganese slag, contaminated soil, and construction waste shale into production raw materials, which are then transported to the raw material homogenization silo. This realizes the resource utilization of waste, reduces the pollution of the environment by waste, lowers the dependence of cement production on natural resources, and improves resource utilization.

[0023] Secondly, the powder conveying-heat exchange and decomposition unit, calcination unit, and cooling unit work closely together. From the conveying and decomposition of powder, the calcination of hot raw materials to the cooling of finished products, each link is seamlessly connected, ensuring the efficient production of pozzolanic composite materials, improving production efficiency, and guaranteeing the stability of product quality.

[0024] Third, the exhaust gas treatment unit cools and removes dust from the kiln head exhaust gas, and discharges it after it meets the standards, effectively reducing the pollution of the atmospheric environment by harmful gases and dust; the storage unit stores the volcanic ash mixture and kiln ash in a reasonable manner, avoiding secondary pollution, meeting environmental protection requirements, and contributing to green production.

[0025] Fourth, the combustion unit provides heat to the calcination unit, ensuring the calcination of raw materials. Moreover, the various units within the system cooperate with each other, and the waste heat can be utilized by other processes to a certain extent, improving energy efficiency, reducing energy consumption, achieving energy conservation and emission reduction, and conforming to the concept of sustainable development. Attached Figure Description

[0026] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0027] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0028] Figure 1 is a schematic diagram of the structure of the cement kiln co-processing manganese slag to produce pozzolanic composite material provided in the embodiment of this utility model.

[0029] In the diagram, 1. Bucket elevator; 2. Pneumatic three-way valve; 3. Air conveying chute; 4. Rotary unloader; 5. Electro-hydraulic plug-in valve; 6. Preheating decomposition furnace subsystem; 7. Rotary kiln; 8. Grate cooler; 9. Cooling fan; 10. Kiln head burner; 11. Kiln head waste heat boiler; 12. Bag filter; 13. Kiln head exhaust fan; 14. Chain bucket conveyor; 15. Chain conveyor. Detailed Implementation

[0030] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0032] Referring to Figure 1, this utility model embodiment provides a system for co-processing manganese slag in a cement kiln to produce pozzolanic composite materials, including a raw material processing-homogenization unit, a powder conveying-heat exchange and decomposition unit, a calcination unit, a cooling unit, a waste gas treatment unit, a storage unit, and a combustion unit.

[0033] The raw material processing-homogenization unit processes manganese slag, contaminated soil, and construction waste shale before transporting them to the raw material homogenization silo. Through a crushing process, the lumpy manganese slag, contaminated soil, and construction waste shale are pulverized into smaller particles, increasing the specific surface area of ​​the materials and facilitating subsequent homogenization, batching, and grinding operations. The homogenization process ensures uniform mixing of materials from different sources and with varying compositions, guaranteeing the stability of subsequent production. The batching stage precisely adjusts the proportions of various raw materials according to the production requirements of the pozzolanic composite. Grinding further refines the materials to achieve a suitable particle size distribution, which is beneficial for full reaction in subsequent processes. Finally, the materials are transported to the raw material homogenization silo for storage and re-homogenization, ensuring the uniformity and stability of the materials entering the next process.

[0034] The powder conveying-heat exchange and decomposition unit is connected to the raw material homogenization silo and is used to convey and decompose pozzolanic powder. In this embodiment, the powder conveying-heat exchange and decomposition unit includes a bucket elevator 1, a pneumatic three-way valve 2, an air conveying chute 3, a rotary unloader 4, an electro-hydraulic plug-in valve 5, and a preheating decomposition furnace subsystem 6 connected in sequence. The powder conveying-heat exchange and decomposition unit conveys the pozzolanic powder from the raw material homogenization silo and decomposes it through heat exchange in the preheating decomposition furnace system 6. The preheating decomposition furnace system 6 does not inject fuel and only serves as a ventilation duct.

[0035] Specifically, the bucket elevator 1 continuously lifts materials using buckets, raising the powder at the bottom of the raw material homogenization silo to a certain height for subsequent transport using gravity and airflow. The pneumatic three-way valve 2 controls the powder's transport path by changing the airflow direction, enabling the powder to be diverted or merged, allowing it to smoothly enter the air conveying chute 3. The air conveying chute 3 uses air to fluidize the powder within the chute, and relying on the chute's inclination angle and aerodynamics, the powder is quickly and efficiently transported to the rotary unloader 4. The rotary unloader 4 controls the discharge volume and speed of the powder through rotation, evenly transporting the powder to the electro-hydraulic plug-in valve 5. The electro-hydraulic plug-in valve 5 acts like a switch, precisely controlling the entry of powder into the preheating decomposition furnace subsystem 6 according to production process requirements. Within the preheating decomposition furnace system 6, the waste heat from the high-temperature exhaust gas at the kiln tail is used to decompose the volcanic ash powder through heat exchange, breaking down components such as carbonates, thus reducing the burden on subsequent calcination. Furthermore, the decomposition furnace does not inject fuel, but only utilizes waste heat, thereby improving energy efficiency.

[0036] The calcination unit is connected to the powder conveying-heat exchange decomposition unit, and is used to calcine the hot raw materials. In this embodiment, the calcination unit includes a rotary kiln 7, which is connected to the preheating decomposition furnace subsystem 6. The rotary kiln 7 calcines the hot raw materials after heat exchange decomposition. The rotary kiln 7 is the core equipment for calcination. Under high temperature conditions, the hot raw materials slowly advance within the rotary kiln 7 as the kiln body rotates. The high temperature inside the kiln is generated by the combustion of pulverized coal provided by the combustion unit, and the temperature is controlled within a range suitable for calcining the pozzolanic composite. During the calcination process, the material undergoes a series of complex physical and chemical reactions, such as solid-phase reactions and crystal structure transformations, causing the material to form a pozzolanic composite with specific properties, completing the key transformation process from raw material to product.

[0037] The cooling unit is connected to the calcination unit and is used to cool the calcined pozzolanic mixture. In this embodiment, the cooling unit includes a grate cooler 8 and a cooling fan 9. The grate cooler 8 is connected to the rotary kiln 7, and the cooling fan 9 provides air to the grate cooler 8 to cool the calcined pozzolanic mixture. When the high-temperature pozzolanic mixture enters the grate cooler 8 from the rotary kiln 7, the cooling fan 9 blows cold air into the grate cooler 8. The cold air undergoes intense heat exchange with the high-temperature material, rapidly removing the heat and quickly lowering the material temperature. This not only benefits subsequent storage and transportation but also stabilizes the crystal structure of the pozzolanic mixture, ensuring its stable performance. Simultaneously, the heated air can be returned to the kiln as secondary or tertiary air for combustion support, improving energy efficiency.

[0038] The waste gas treatment unit is connected to the kiln head of the calcination unit and is used to treat the waste gas from the kiln head. In this embodiment, the waste gas treatment unit includes a kiln head waste heat boiler 11, a bag filter 12, and a kiln head exhaust fan 13. The kiln head waste heat boiler 11 is connected to the grate cooler 8 to cool the waste gas from the kiln head. The bag filter 12 is connected to the kiln head waste heat boiler 11 for dust removal. The kiln head exhaust fan 13 is connected to the bag filter 12 to discharge the qualified waste gas into the atmosphere. The waste gas from the kiln head is at a high temperature when it is discharged from the grate cooler 8 and contains a large amount of heat energy and dust. The kiln head waste heat boiler 11 uses the waste heat of the waste gas to generate steam, realizing waste heat recovery and reducing the temperature of the waste gas. The cooled waste gas enters the bag filter 12, where the bag filter 12 uses a filter medium to intercept the dust in the waste gas on the surface of the filter bags, allowing the purified gas to pass through. Finally, the kiln head exhaust fan 13 provides power to discharge the exhaust gas, which has undergone dust removal and meets emission standards, into the atmosphere, reducing environmental pollution.

[0039] The storage unit is connected to the cooling unit-exhaust gas treatment unit and is used to store pozzolanic composite material and kiln ash. In this embodiment, the storage unit includes a chain bucket conveyor 14, which is connected to the grate cooler 8 to transport the cooled pozzolanic composite material to the clinker silo for storage. The storage unit also includes a chain conveyor 15, whose feed end is connected to the kiln head waste heat boiler 11 and the bag filter 12. The chain conveyor 15 transports the collected kiln ash to the clinker silo via the chain bucket conveyor 14. The chain bucket conveyor 14 drives the buckets via chains to transport the cooled pozzolanic composite material from the grate cooler 8 to the clinker silo, thus storing the product. The chain conveyor 15 is responsible for collecting the kiln ash from the kiln head waste heat boiler 11 and the bag filter 12, and using chain drive to transport the kiln ash to the chain bucket conveyor 14, which is then sent to the clinker silo for storage. This design enables the effective collection and storage of various materials during the production process, preventing material loss and facilitating subsequent use and management.

[0040] The combustion unit is connected to the calcination unit and provides heat for calcination. In this embodiment, the combustion unit includes a kiln head burner 10, which is connected to the rotary kiln 7 to inject pulverized coal into the rotary kiln 7 for combustion, providing heat for the calcination of raw materials. The kiln head burner 10 mixes pulverized coal and air in a certain proportion and injects it into the rotary kiln 7. The pulverized coal burns rapidly in the high-temperature environment inside the kiln, releasing a large amount of heat energy, providing the necessary high-temperature conditions for the calcination of hot raw materials in the rotary kiln 7. By controlling the amount of coal injected and the air distribution ratio of the burner, the temperature inside the kiln can be adjusted to ensure a stable and efficient calcination process, guaranteeing the calcination quality of the pozzolanic composite material.

[0041] The workflow of this utility model is as follows:

[0042] First, raw material pretreatment and homogenization: The raw material processing-homogenization unit first processes manganese slag, contaminated soil, and construction waste shale. A crusher breaks these raw materials into small pieces to increase their surface area, facilitating subsequent processing; homogenization equipment mixes raw materials of different properties uniformly, ensuring stable composition; a batching device adjusts the raw materials according to specific proportions to meet production requirements; grinding equipment further refines the raw materials, ensuring their particle size meets production standards, and finally, they are transported to the raw material homogenization silo for secondary homogenization, providing uniform raw materials for subsequent production.

[0043] Second, powder conveying and heat exchange decomposition: The powder conveying-heat exchange decomposition unit obtains pozzolanic powder from the raw material homogenization silo. A bucket elevator 1 lifts the powder to a high position, where it enters a pneumatic three-way valve 2 using gravity and airflow. This valve controls the powder's conveying direction, directing it into an air conveying chute 3. In the chute, air fluidizes the powder, achieving efficient conveying. A rotary unloader 4 regulates the powder flow rate and speed, while an electro-hydraulic plug-in valve 5 controls the powder's entry into the preheating decomposition furnace subsystem 6. Within the preheating decomposition furnace system 6, the powder undergoes heat exchange decomposition using the residual heat of the high-temperature exhaust gas from the kiln tail, decomposing components such as carbonates, reducing the burden on subsequent calcination. Furthermore, the decomposition furnace serves only as a ventilation duct, without injecting fuel, thus improving energy utilization.

[0044] Third, calcination: The rotary kiln 7 of the calcination unit is connected to the preheating decomposition furnace subsystem 6 to receive the decomposed hot raw materials. The kiln head burner 10 of the combustion unit injects pulverized coal into the rotary kiln 7 for combustion, generating a high-temperature environment, with the calcination temperature controlled at 900℃-1000℃. The hot raw materials undergo complex physicochemical reactions inside the kiln, such as solid-phase reactions and crystal structure transformations, gradually forming a pozzolanic composite material.

[0045] Fourth, cooling: The grate cooler 8 of the cooling unit receives the high-temperature pozzolanic mixture from the rotary kiln 7. Cooling fans 9 supply cold air to the grate cooler 8, where the cold air exchanges heat with the high-temperature material, rapidly reducing its temperature. The cooled material has stable properties, facilitating storage and transportation. Simultaneously, the heated air can be returned to the kiln as secondary or tertiary air to aid combustion, improving energy efficiency.

[0046] Fifth, waste gas treatment: The waste gas treatment unit treats the kiln head waste gas. The kiln head waste heat boiler 11 utilizes the waste heat from the high-temperature waste gas discharged from the grate cooler 8 to generate steam, realizing waste heat recovery and reducing the waste gas temperature. The cooled waste gas enters the bag filter 12, where dust is intercepted by the filter media. The purified waste gas is discharged into the atmosphere in compliance with standards under the action of the kiln head exhaust fan 13, reducing environmental pollution.

[0047] Sixth, storage: The storage unit is responsible for collecting and storing products and kiln ash. The chain bucket conveyor 14 transports the cooled pozzolanic mixture from the grate cooler 8 to the clinker silo. The chain conveyor 15 collects kiln ash from the waste heat boiler 11 at the kiln head and the bag filter 12, and transports it to the chain bucket conveyor 14, and finally sends it to the clinker silo for storage, facilitating subsequent use and management.

[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A system for co-processing manganese slag in a cement kiln to produce pozzolanic composite materials, characterized in that, The system includes a raw material processing-homogenization unit, a powder conveying-heat exchange and decomposition unit, a calcination unit, a cooling unit, a waste gas treatment unit, a storage unit, and a combustion unit. The raw material processing-homogenization unit processes manganese slag, contaminated soil, and construction waste shale before conveying it to a raw material homogenization silo. The powder conveying-heat exchange and decomposition unit is connected to the raw material homogenization silo and is used to convey and decompose pozzolanic powder. The calcination unit is connected to the powder conveying-heat exchange and decomposition unit and is used to calcine the hot raw materials. The cooling unit is connected to the calcination unit and is used to cool the calcined pozzolanic mixture. The waste gas treatment unit is connected to the kiln head of the calcination unit and is used to treat kiln head waste gas. The storage unit is connected to the cooling-waste gas treatment unit and is used to store the pozzolanic mixture and kiln ash. The combustion unit is connected to the calcination unit and is used to provide heat for calcination.

2. The system for co-processing manganese slag in a cement kiln to produce pozzolanic composite materials according to claim 1, characterized in that, The powder conveying-heat exchange and decomposition unit includes a bucket elevator (1), a pneumatic three-way valve (2), an air conveying chute (3), a rotary unloader (4), an electro-hydraulic plug-in valve (5), and a preheating decomposition furnace system (6) connected in sequence. The powder conveying-heat exchange and decomposition unit conveys the pozzolanic powder from the raw material homogenization silo and decomposes it in the preheating decomposition furnace system (6). The preheating decomposition furnace system (6) does not inject fuel and only serves as a ventilation duct.

3. The system for co-processing manganese slag in a cement kiln to produce pozzolanic composite materials according to claim 2, characterized in that, The calcination unit includes a rotary kiln (7), which is connected to the preheating decomposition furnace subsystem (6). The rotary kiln (7) calcines the hot raw materials after heat exchange decomposition.

4. The system for co-processing manganese slag in a cement kiln to produce pozzolanic composite materials according to claim 1, characterized in that, The cooling unit includes a grate cooler (8) and a cooling fan (9). The grate cooler (8) is connected to the rotary kiln (7), and the cooling fan (9) provides air to the grate cooler (8) to cool the calcined pozzolanic composite material.

5. A system for co-processing manganese slag in a cement kiln to produce pozzolanic composite materials according to claim 4, characterized in that, The waste gas treatment unit includes a kiln head waste heat boiler (11), a bag filter (12), and a kiln head exhaust fan (13). The kiln head waste heat boiler (11) is connected to the grate cooler (8) to cool the kiln head waste gas. The bag filter (12) is connected to the kiln head waste heat boiler (11) for dust removal. The kiln head exhaust fan (13) is connected to the bag filter (12) to discharge the qualified waste gas into the atmosphere.

6. A system for co-processing manganese slag in a cement kiln to produce pozzolanic composite materials according to claim 5, characterized in that, The storage unit includes a chain bucket conveyor (14), which is connected to the grate cooler (8) to transport the cooled pozzolanic mixture to the clinker silo for storage; the storage unit also includes a chain conveyor (15), the feed end of which is connected to the kiln head waste heat boiler (11) and the bag filter (12), and the chain conveyor (15) transports the collected kiln ash to the clinker silo via the chain bucket conveyor (14).

7. A system for co-processing manganese slag in a cement kiln to produce pozzolanic composite materials according to claim 6, characterized in that, The combustion unit includes a kiln head burner (10), which is connected to the rotary kiln (7) to inject pulverized coal into the rotary kiln for combustion to provide heat for the calcination of raw materials.

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