Clay calcination and color control system and method

Abstract

The invention provides a clay calcination and color control system and method. The system comprises a clay calcination rotary kiln, a hot blast stove, a reducing gas generator and an indirect heat exchange cooler. The clay calcining rotary kiln comprises a kiln feeding cover, a kiln cylinder body, a kiln discharging cover and a first air locking discharging valve. The kiln feeding cover is arranged at the high end of the kiln cylinder body, and the kiln discharging cover is arranged at the low end of the kiln cylinder body. The hot blast stove is communicated with the kiln discharging cover, and the kiln feeding cover is provided with a waste gas port, so that clay and high-temperature flue gas flow reversely; the indirect heat exchange cooling machine comprises a cooling machine feeding pipe, a cooling machine barrel body and a cooling machine kiln discharging cover; the first air-locking discharging valve is arranged at the bottom of the kiln discharging cover, and the cooling machine cylinder body is arranged below the kiln discharging cover and communicates with the first air-locking discharging valve; and the reducing gas generator is arranged at the lower part of the kiln discharging cover and is used for blowing reducing gas into the kiln discharging cover, so that the reducing gas and the calcined clay are subjected to a reduction reaction, and the reddish brown ferric oxide is reduced into black ferroferric oxide.

Description

Technical Field

[0001] The invention relates to the technical field of cement kilns, and in particular to a clay calcination and color control system and method. Background Art

[0002] Color control in cement clinker is of great significance in cement production, especially in affecting the appearance and quality of the final cement product. The color of cement clinker is mainly determined by factors such as mineral composition, firing temperature, fuel type and chemical reaction process. Color control has a direct impact on the appearance consistency, market acceptance and application of cement in the construction industry.

[0003] As a building material, cement not only requires good strength and durability, but also consistency in appearance. Consumers have certain preferences for the color of cement, especially in decorative building applications. The color of cement is often regarded as an important indicator of its quality, especially in the fields of high-end construction and decorative concrete. Inconsistent cement color may affect the market competitiveness of the product. Color control also reflects the stability of the production process. For example, if cement clinker appears excessively black or uneven in color, it may mean that the combustion process is incomplete or that certain chemical reactions have failed to achieve the expected results. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a clay calcination and color control system and method to eliminate or improve one or more defects existing in the prior art.

[0005] In a first aspect, the present invention provides a clay calcining and color control system, the system comprising a clay calcining rotary kiln, a hot blast furnace, a reducing gas generator and an indirect heat exchange cooler; The clay calcining rotary kiln comprises a kiln inlet cover, a kiln body, a kiln outlet cover and a first air-locking discharge valve; The kiln body is arranged obliquely, the kiln inlet cover is arranged at the high end of the kiln body, and the kiln outlet cover is arranged at the low end of the kiln body, so that the clay material is fed into the high end of the clay calcining rotary kiln, and the calcined clay material is discharged from the low end; The hot blast furnace is connected to the kiln discharge cover through a pipeline or directly, and the kiln inlet cover has an exhaust gas port, so that the high-temperature flue gas provided by the hot blast furnace enters the kiln body at the lower end, and the exhaust gas is discharged from the higher end; The indirect heat exchange cooler comprises a cooler feeding pipe, a cooler barrel and a cooler kiln discharge cover; The first air-locking discharge valve is arranged at the bottom of the kiln discharge cover, the cooler barrel is arranged below the kiln discharge cover and is connected with the first air-locking discharge valve through a cooler feeding pipe at the front end thereof, and the cooler kiln discharge cover is arranged at the end of the cooler barrel; The reducing gas generator is arranged at the lower part of the kiln discharge cover, and is used to blow reducing gas into the kiln discharge cover so as to cause reducing reaction with the calcined clay, and reduce the reddish brown ferric oxide to black ferrosoferric oxide.

[0006] In some embodiments, the kiln body of the clay calcining rotary kiln includes a drying section and a calcining section, and the angle of the kiln body relative to the horizontal plane is set to 1°~3°; Wherein, the inner wall of the drying section is provided with a lifting plate, and the lifting plate includes a plurality of groups of inclined lifting plates, L-shaped lifting plates and arc-shaped lifting plates arranged at intervals; The inner wall of the calcining section is provided with a refractory layer.

[0007] In some embodiments, the clay calcining rotary kiln further comprises a kiln transmission device, the kiln transmission device comprises a speed regulating motor, a reducer, a gear and a gear ring, wherein the speed regulating motor is connected to the gear through the reducer, the gear ring is connected to the kiln body, and the gear is meshed with the gear ring; The clay calcining rotary kiln also includes multiple groups of kiln belts and kiln supporting devices, wherein the kiln belts are fixedly arranged on the outer peripheral wall of the kiln shell, and the kiln supporting devices are fixedly arranged on the bottom of the kiln shell for supporting the rotation of the kiln belts.

[0008] In some embodiments, the hot blast furnace is equipped with a flue gas temperature control structure to control the high temperature flue gas temperature of the calcining section of the clay calcining rotary kiln to be between 850°C and 950°C.

[0009] In some embodiments, the cooling machine body of the indirect heat exchange cooling machine is arranged tilted, and its angle relative to the horizontal plane is set to 1°~3°; The cooler feeding pipe is arranged at the high end of the cooler barrel, and a cooler discharge cover is arranged at the bottom end of the cooler barrel.

[0010] In some embodiments, a second air-locking discharge valve is provided at the bottom of the cooler discharge hood to prevent outside air from entering the cooler barrel when the clay passes through the second air-locking discharge valve.

[0011] In some embodiments, the indirect heat exchange cooler further includes a blower, a cooling air inlet duct, a cooling air inlet hood, a cooling air duct, a cooler outlet hood and a waste heat recovery duct; Wherein, the blower is connected to the cooling air inlet hood through the cooling air inlet duct, and the cooling air inlet hood is arranged at the bottom end of the cooling machine barrel; The cooling air ducts are provided in plurality and are arranged inside the cooling machine barrel along the axial direction thereof; inside the cooling machine barrel, the cooling air ducts are sealed so that the cooling air does not contact the clay material; The heat recovery pipeline is arranged at the high end of the cooling machine barrel and is connected to the cooling air pipeline.

[0012] In some embodiments, the cooling air absorbs the heat of the clay material in the cooler barrel and is converted into high-temperature gas; The heat recovery pipeline is connected to the kiln discharge cover to introduce the high-temperature flue gas provided by the hot blast furnace that absorbs the high-temperature gas and mixes with the high-temperature gas into the kiln body of the clay calcining rotary kiln; The gas outlet of the heat recovery pipeline is located higher than the first air-locking discharge valve and the reducing gas generator.

[0013] In some embodiments, the indirect heat exchange cooler further comprises a cooler transmission device, the cooler transmission device comprises a reduction motor, a gear and a ring gear, wherein the reduction motor is connected to the gear, the ring gear is connected to the cooler barrel, and the gear is meshed with the ring gear; The indirect heat exchange cooler also includes multiple sets of cooler belts and cooler support devices, wherein the cooler belts are fixedly arranged on the outer peripheral wall of the cooler barrel, and the cooler support device is fixedly arranged on the bottom of the cooler barrel for supporting the rotation of the cooler belts.

[0014] In a second aspect, the present invention provides a method for calcining and controlling the color of clay. The implementation of the method is based on the above-mentioned clay calcining and color control system, and the method comprises the following steps: The high-temperature flue gas of the hot blast furnace is used to preheat the interior of the clay calcining rotary kiln, and the kiln transmission device is started to rotate the clay calcining rotary kiln; Feed clay materials into the clay calcining rotary kiln at the kiln inlet cover, so that the clay and the high-temperature flue gas flow in the opposite direction, and the exhaust gas is discharged from the exhaust port of the kiln inlet cover; Control the temperature and flow of the high-temperature flue gas of the hot blast furnace, and control the temperature and flow of the waste heat recovery pipeline. The high-temperature flue gas of the hot blast furnace is maintained at 850°C to 950°C, so that the activation temperature of the clay material is controlled at 800°C to 850°C; Control the heat exchange time of clay materials in the clay calcining rotary kiln to complete the clay calcination after 60 to 120 minutes and reach the kiln discharge cover; Controlling the reducing gas generator to blow reducing gas at a temperature of 600°C to 800°C into the kiln discharge cover, so that the reducing gas reduces the reddish brown ferroferric oxide in the clay into black ferroferric oxide, wherein the reducing gas includes carbon monoxide with a specific concentration; The first air-locking discharge valve at the bottom of the kiln discharge cover is controlled to discharge the clay material into the indirect heat exchange cooler. The cooled clay material is discharged through the second air-locking discharge valve with a temperature lower than 120°C to obtain cement clinker.

[0015] The embodiment of the present invention provides a system and method for adjusting the color of a product by precisely controlling the ferric oxide reduction reaction during the clay calcination process. By introducing a reducing gas, the reddish-brown ferric oxide is reduced to black ferrosoferric oxide, thereby achieving effective color control and enhancing the market adaptability of clay products. This process not only improves the appearance, but may also affect other properties of the product, such as strength and durability, and therefore has great practical application potential.

[0016] Additional advantages, purposes, and features of the present invention will be described in part in the following description, and will become apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The purposes and other advantages of the present invention may be achieved and obtained by the structures specifically indicated in the specification and the accompanying drawings.

[0017] Those skilled in the art will appreciate that the objectives and advantages that can be achieved with the present invention are not limited to the above specific description, and the above and other objectives that can be achieved by the present invention will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention. The components in the drawings are not drawn to scale, but are only for illustrating the principles of the present invention. In order to facilitate the illustration and description of some parts of the present invention, the corresponding parts in the drawings may be enlarged, that is, they may become larger relative to other components in the exemplary device actually manufactured according to the present invention. In the drawings: Figure 1 It is a structural schematic diagram of a clay calcination and color control system in one embodiment of the present invention.

[0019] Figure 2 for Figure 1 Cross-sectional view at A.

[0020] Figure 3 The figure is a flowchart of a clay calcination and color control method in one embodiment of the present invention.

[0021] Reference numerals: 100, clay calcining rotary kiln; 110, kiln inlet cover; 111, kiln inlet seal; 120, kiln body; 121, drying section; 122, calcining section; 123, lifting plate; 124, refractory layer; 130, kiln discharge cover; 131, kiln discharge seal; 132, first air lock discharge valve; 140, kiln transmission device; 141, speed regulating motor; 142, reducer; 151, kiln wheel belt; 152, kiln support device; 160, hot air furnace; 170, reducing gas generator; 200, indirect heat exchange cooler; 210, cooler feeding pipe; 211, cooler inlet seal; 220, cooler barrel; 230, cooler kiln discharge cover; 231, cooler discharge cover seal; 232, second air lock discharge valve; 241. Blower; 242. Cooling air inlet duct; 243. Cooling air inlet cover; 244. Cooling machine air inlet duct seal; 245. Cooling air duct; 246. Cooling machine air outlet cover; 247. Cooling machine air outlet cover seal; 248. Waste heat recovery pipeline; 251. Cooler wheel belt; 252. Cooler support device; 260. Cooler transmission device. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0023] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0024] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0025] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection involving an intermediate.

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0027] In a first aspect, the present invention provides a clay calcination and color control system, such as Figure 1As shown, the system may include a clay calcining rotary kiln 100, a hot blast furnace 160, a reducing gas generator 170, an indirect heat exchange cooler 200, and the like.

[0028] The clay calcining rotary kiln 100 includes a kiln inlet cover 110, a kiln body 120, a kiln outlet cover 130, and a first air-locking discharge valve 132. The kiln body 120 is arranged at an angle to ensure the flow of clay in the rotary kiln and the uniformity of the calcining process; the clay material is subjected to high-temperature treatment here. The kiln inlet cover 110 is arranged at the high end of the kiln body 120 and is responsible for delivering the clay material into the kiln body 120. The kiln outlet cover 130 is arranged at the low end of the kiln body 120 and is responsible for discharging the calcined clay material. The first air-locking discharge valve 132 is located at the bottom of the kiln outlet cover 130, and its main function is to control the airflow (to prevent high-temperature flue gas from entering the cooler) so that the calcined material can be discharged smoothly.

[0029] The hot blast furnace 160 is connected to the kiln discharge cover 130 through a pipeline or directly, and the kiln inlet cover 110 has an exhaust gas port. The hot blast furnace 160 is used to provide high-temperature flue gas to increase the temperature in the kiln and promote the calcination reaction of clay.

[0030] In the above embodiment, the clay in the kiln and the hot flue gas are countercurrently heat exchanged, that is, the high-temperature flue gas provided by the hot blast furnace 160 enters the lower end of the kiln body 120, and the exhaust gas is discharged from the higher end; the clay material is fed into the higher end of the clay calcining rotary kiln 100, and the calcined clay material is discharged from the lower end. Countercurrent heat exchange can make the high-temperature flue gas fully contact with the cooled clay material, thereby effectively transferring heat to the clay material. In this way, the clay material in the kiln can absorb as much heat as possible before entering the kiln body 120, reducing the consumption of external energy and reducing production costs. The countercurrent design can maximize the use of the waste heat of the rotary kiln by allowing the flue gas to enter from the lower end of the kiln and gradually heat up, avoiding the direct discharge of high-temperature flue gas and reducing the waste of heat energy. In the process of the clay material moving from the higher end to the lower end in the kiln, it can achieve more uniform heating through countercurrent contact with the hot flue gas. In this way, the temperature of the clay material rises more steadily, which helps to improve the uniformity of the calcination process, thereby achieving better calcination results and reducing the phenomenon of overheating or under-calcination. The clay is continuously heated by the hot flue gas in the kiln, so that the minerals in the clay (such as ferric oxide) can fully react within a more suitable temperature range, thereby improving the calcination effect and reaction rate of the material. Countercurrent heat exchange can also reduce the exhaust gas temperature. Because the hot flue gas has been cooled by heat exchange with the material before entering the rotary kiln, the exhaust gas temperature is lower, which helps to reduce environmental pollution and reduce the requirements for emission control equipment (such as flue gas desulfurization, denitrification devices, etc.). The countercurrent design helps to accurately control the temperature distribution in the kiln. As the hot flue gas flows from the low end to the high end, the flue gas temperature gradually decreases, which helps to regulate the temperature at different calcination stages and ensure the uniformity of the temperature in the kiln, thereby improving the stability and consistency of the entire production process.

[0031] Further, the indirect heat exchange cooler 200 is used to reduce the temperature of the clay material, and may include a cooler feeding pipe 210, a cooler barrel 220, and a cooler kiln discharge cover 230. The first air lock discharge valve 132 is arranged at the bottom of the kiln discharge cover 130, the cooler barrel 220 is arranged below the kiln discharge cover 130 and is connected to the first air lock discharge valve 132 through the cooler feeding pipe 210 located at the front end thereof, and is used to feed the discharged calcined material into the cooler barrel 220, and the cooler kiln discharge cover 230 is arranged at the end of the cooler barrel 220.

[0032] Furthermore, the reducing gas generator 170 is disposed at the lower part of the kiln discharge cover 130, and is used to blow reducing gas into the kiln discharge cover 130, so that it reacts with the calcined clay to reduce the reddish brown ferric oxide to black ferric oxide. The reducing gas generator 170 burns fuel in an oxygen-deficient state to generate reducing gas with a temperature of 600°C to 800°C and a certain concentration of carbon monoxide. During the clay calcination process, ferric oxide ( ) often gives the material a reddish brown color; the reddish brown ferric oxide in the clay is reduced to black ferric oxide at the bottom of the kiln discharge cover 130, thereby achieving the color control of the clay material. The excess carbon monoxide gas after the reduction of the reducing gas and ferric oxide enters the kiln and reacts with the oxygen in the high-temperature flue gas to generate carbon dioxide. The first air lock discharge valve 132 prevents the high-temperature flue gas in the kiln discharge cover 130 from entering the rotary indirect cooler during discharge, thereby preventing the clay from being oxidized.

[0033] The present invention provides a system for adjusting the color of a product by precisely controlling the reduction reaction of ferric oxide during the calcination of clay. By introducing reducing gas, reddish-brown ferric oxide is reduced to black ferric oxide, thereby achieving effective color control and enhancing the market adaptability of clay products. This process not only improves the appearance, but may also affect other properties of the product, such as strength and durability, and therefore has great practical application potential.

[0034] In some embodiments, the angle of the kiln body 120 relative to the horizontal plane is set to 1°~3°; this design can ensure that the material has an appropriate slope in the kiln, promoting uniform flow and heat transfer of the material. The material in the kiln slides to the lower end due to gravity and fully contacts with the hot flue gas to achieve heat exchange and calcination. The angle design helps to prevent the material from stagnating in the kiln and improve the efficiency of the material passing through the kiln. This setting maximizes the contact time and heat exchange effect between the material and the flue gas, ensures the uniformity of heating of the material, and can reduce the problem of incomplete calcination caused by accumulation or retention of the material.

[0035] In some embodiments, the kiln body 120 of the clay calcining rotary kiln 100 includes a drying section 121 and a calcining section 122. Drying and calcining are performed simultaneously in the body of a rotary kiln and continuous production is achieved, which can achieve large-scale production capacity. The length of the drying section 121 can be matched according to the moisture content of the fed clay; the temperature of the drying section 121 is relatively low, while the temperature of the calcining section 122 is higher. The temperature distribution in the kiln needs to be precisely controlled according to the characteristics and processing requirements of the material. After the material enters the kiln barrel, it first enters the drying section 121. At this stage, the material evaporates water by heating with high-temperature gas. As the kiln barrel rotates, the material is continuously pushed and gradually enters the calcining section 122 with a higher temperature. The flow rate, residence time and heat exchange efficiency of the material can be carefully designed to ensure the processing effect of the material in different sections.

[0036] Furthermore, the inner wall of the drying section 121 is provided with a material raising plate 123, such as Figure 2 As shown, the lifting plate 123 includes several groups of inclined lifting plates, L-shaped lifting plates and arc-shaped lifting plates arranged at intervals. In the drying section 121, the lifting plates 123 are used to help the material to turn over and spread, increase the contact area between the material and the hot air flow, and improve the water evaporation efficiency. These lifting plates 123 enhance the heat exchange and moisture removal of the material by disturbing the material, ensuring that the material is dried efficiently at a lower temperature. The inclined lifting plate can lift the material at a certain angle, increase the contact area with the flue gas, promote heat transfer and evaporation of moisture in the material. The design of the L-shaped lifting plate can promote the turning and uniform distribution of the material, and improve the heat exchange effect of the drying section 121. The arc-shaped lifting plate can change the flow trajectory of the material through its curved shape, so that it flows more evenly in the kiln tube, and enhance the contact time between the material and the flue gas through the reflection effect of the lifting plate 123, thereby promoting heat transfer. The combined use of various types of lifting plates 123 can effectively increase the relative movement between the material and the flue gas, improve the heat exchange efficiency, ensure that the material is evenly and fully heated in the drying section 121, and reduce the phenomenon of uneven drying.

[0037] Furthermore, the inner wall of the calcining section 122 is provided with a refractory layer 124. In the calcining section 122, the material needs to undergo a chemical reaction at a relatively high temperature, and the role of the refractory layer 124 is particularly important. The refractory layer 124 can effectively reflect the heat in the kiln, prevent heat loss, and improve the thermal efficiency in the kiln. The refractory layer 124 can withstand high-temperature heat flow and mechanical impact, reduce the wear of the kiln wall, and extend the service life of the equipment. Optionally, the refractory layer 124 can use laid refractory bricks and poured refractory materials. The refractory layer 124 can not only provide effective temperature protection, but also improve the overall thermal efficiency in the kiln by reducing heat loss. At the same time, the refractory layer 124 can maintain the stability of the kiln wall and reduce structural damage caused by temperature changes, thereby ensuring the stability of the calcining process.

[0038] In the above embodiment, the heat exchange efficiency, material handling quality and equipment durability are effectively improved by rationally allocating and optimizing the drying section 121 and calcining section 122 of the rotary kiln, and coordinating different types of lifting plates 123 and refractory layers 124. This design ensures that the rotary kiln can achieve high thermal efficiency and stable production effects when calcining clay, and ultimately improves the economic benefits of the production process and product quality.

[0039] In some embodiments, the clay calcining rotary kiln 100 further includes a kiln transmission device 140, such as Figure 1 As shown, the kiln transmission device 140 includes a speed regulating motor 141, a reducer 142, a gear and a ring gear, wherein the speed regulating motor 141 is connected to the gear through the reducer 142, the ring gear is connected to the kiln body 120, and the gear is meshed with the ring gear. The speed regulating motor 141 is one of the core parts of the rotary kiln transmission system and is responsible for providing power. Its speed is adjustable and the rotation speed of the rotary kiln drum can be accurately controlled as needed. Through the speed regulating motor 141, the residence time of the material in the rotary kiln can be optimized to ensure the uniformity and efficiency of the calcination or drying process. The reducer 142 drives the rotary kiln drum to rotate by converting the high-speed rotation of the motor into low-speed, high-torque power, which plays a role in deceleration and torque increase in the transmission system, so that the drum of the rotary kiln can rotate at a suitable speed. The gear is meshed with the ring gear to transmit the power output by the reducer 142 to the rotary kiln drum. The meshing accuracy and strength of the gears and gear rings are crucial to the rotation stability of the kiln drum, ensuring that the rotary kiln runs smoothly during operation and avoiding mechanical failures caused by gear wear or poor meshing.

[0040] In some embodiments, the clay calcining rotary kiln 100 further includes a plurality of kiln belts 151 and a kiln support device 152, wherein the kiln belt 151 is a mechanical support component, which can be a steel ring structure, fixedly arranged on the outer peripheral wall of the kiln barrel 120; the role of the kiln belt 151 is to provide additional support force through friction with the rotary kiln barrel and ensure the stable rotation of the kiln barrel. Under high temperature and heavy load working conditions, the kiln belt 151 helps to disperse the weight and pressure of the kiln barrel and prevent the kiln barrel from deflecting or tilting. The kiln support device 152 is fixedly arranged at the bottom of the kiln barrel 120 for supporting the rotation of the kiln belt 151. As at least one achievable manner, the kiln support device 152 can be composed of a group of supporting wheels and brackets, which are installed at the bottom of the rotary kiln to support the kiln belt 151 and allow it to rotate freely. The design of the support device can ensure that the kiln barrel can operate stably while being able to withstand the load of the rotary kiln. Especially when operating at high speed and high temperature, the durability and strength of the support device are crucial.

[0041] In some embodiments, the hot blast furnace 160 is equipped with a flue gas temperature control structure to control the high temperature flue gas temperature of the calcining section 122 of the clay calcining rotary kiln 100 to 850°C~950°C. The purpose of this design is to ensure that the calcination process in the rotary kiln can be carried out under the optimal temperature conditions, thereby improving the production efficiency and the calcination quality of the material. The flue gas temperature control structure is designed to accurately adjust the flue gas temperature entering the rotary kiln through the hot blast furnace 160 to avoid excessively high or low temperatures affecting the calcination effect. The structure for controlling the temperature may include a temperature control valve, a cooler (or air preheater) temperature sensor, etc. Preferably, the high temperature flue gas is controlled at about 900°C to ensure the calcination temperature of the clay and avoid the clay temperature being too high and losing its activity. This method can improve the calcination quality, ensure the calcination uniformity of the material, save energy, and improve the overall production efficiency. In addition, the automation and precise control of the temperature control structure can reduce human operation errors and improve the stability and reliability of production.

[0042] In some embodiments, the cooler barrel 220 of the indirect heat exchange cooler 200 is arranged at an angle of 1° to 3° relative to the horizontal plane; this inclination angle setting can help the material flow smoothly in the cooler. The inclined design allows the material to flow downward by gravity during the cooling process, reducing the time the material stays in the cooler and improving the cooling efficiency. This design can avoid material blockage and retention and ensure the uniformity of the cooling process. The cooler feeding pipe 210 is arranged at the high end of the cooler barrel 220, and the bottom end of the cooler barrel 220 is provided with a cooler discharge hood. This arrangement is to ensure that the material can enter from the high end of the cooler and naturally slide down to the bottom end of the cooler by gravity for cooling. The function of the discharge hood is to guide the cooled material out of the cooler to avoid blockage and facilitate subsequent processing.

[0043] In some embodiments, a second air-locking discharge valve 232 is provided at the bottom of the cooler discharge hood to prevent outside air from entering the cooler barrel 220 when the clay passes through the second air-locking discharge valve 232, thereby preventing the black ferroferric oxide in the clay from being oxidized into reddish-brown ferric oxide again.

[0044] In some embodiments, the indirect heat exchange cooler 200 further includes a blower 241, a cooling air inlet duct 242, a cooling air inlet hood 243, a cooling air duct 245, a cooler air outlet hood 246, and a waste heat recovery duct 248. The blower 241 is connected to the cooling air inlet hood 243 through the cooling air inlet duct 242, and the cooling air inlet hood 243 is arranged at the bottom end of the cooler barrel 220; the function of the blower 241 is to provide the required cold air or airflow for the cooler. The blower 241 introduces air into the system through the duct to provide a strong airflow for cooling.

[0045] Furthermore, a plurality of cooling air ducts 245 are provided, and are arranged inside the cooling machine barrel 220 along the axial direction thereof; inside the cooling machine barrel 220, the cooling air ducts 245 are sealed so that the cooling air does not contact the clay material; the heat recovery duct is provided at the high end of the cooling machine barrel 220, and is connected to the cooling air duct 245. The cooling method is air cooling, the cooling machine is a rotary indirect heat exchange method, and the cooling air duct 245 is sealed and installed inside the cooling machine barrel 220 to ensure that the cooling air does not directly contact the material, and to prevent the black ferroferric oxide in the clay from being oxidized again into reddish-brown ferric oxide.

[0046] In some embodiments, the cooling air is converted into high-temperature gas after absorbing the heat of the clay material in the cooling machine barrel 220. The heat recovery pipeline is connected to the kiln discharge hood 130 to introduce the high-temperature flue gas provided by the hot blast furnace 160 that absorbs the high-temperature gas into the kiln barrel 120 of the clay calcining rotary kiln 100; the high-temperature gas in the cooler (originally the gas after the cooling air absorbs the heat) is transported to the kiln discharge hood 130 through the heat recovery pipeline. At this time, the role of the heat recovery pipeline is to collect these high-temperature gases, reduce energy waste, and guide them to other areas through the pipeline system to make full use of their thermal energy. The gas outlet of the heat recovery pipeline is located higher than the first air lock discharge valve 132 and the reduction gas generator 170. The first air lock discharge valve 132 is located above the reduction gas generator 170 to prevent high-temperature gas from affecting the reduction reaction.

[0047] In some embodiments, the indirect heat exchange cooler 200 also includes a cooler transmission device 260, and the cooler transmission device 260 includes a reduction motor, a gear and a ring gear, wherein the reduction motor is connected to the gear, the ring gear is connected to the cooler barrel 220, and the gear is meshed with the ring gear.

[0048] In some embodiments, the indirect heat exchange cooler 200 also includes multiple sets of cooler belts 251 and cooler support devices 252, wherein the cooler belts 251 are fixedly arranged on the outer peripheral wall of the cooler barrel 220, and the cooler support device 252 is fixedly arranged on the bottom of the cooler barrel 220, for supporting the rotation of the cooler belts 251.

[0049] The material inlet and outlet and the gas inlet and outlet in the embodiment of the present invention may be provided with corresponding sealing structures, such as the kiln inlet seal 111 provided at the kiln inlet cover 110; the kiln discharge seal 131 provided at the kiln discharge cover 130; the cooler inlet seal 211 provided at the cooler feeding pipe 210; the cooler discharge cover seal 231 provided at the cooler kiln discharge cover 230; the cooler air inlet pipe seal 244 provided at the cooling air inlet cover 243; the cooler outlet cover seal 247 provided at the cooler outlet cover 246, etc. These sealing structure designs not only improve the air tightness and safety of the equipment, but also effectively control the temperature, pressure and gas flow, ensure the energy utilization rate in the production process, and reduce energy waste and environmental pollution. At the same time, good sealing performance also helps to improve the stability of the heating, calcining and cooling processes of the materials, thereby improving product quality and production efficiency. These designs are of great significance for the long-term stable operation, energy saving and consumption reduction, and environmental protection benefits of the equipment.

[0050] In a second aspect, the present invention provides a method for calcining and controlling the color of clay, the implementation of which is based on the above-mentioned clay calcining and color control system, such as Figure 3 As shown, the method comprises the following steps: S10, preheating the interior of the clay calcining rotary kiln 100 by the high-temperature flue gas of the hot blast furnace 160, and starting the kiln transmission device 140 to rotate the clay calcining rotary kiln 100; this step ensures that the rotary kiln has sufficient thermal energy when starting by introducing the high-temperature flue gas into the rotary kiln, thereby avoiding energy waste caused by direct heating or insufficient calcination of the first input materials.

[0051] S20, feeding clay material into the clay calcining rotary kiln 100 at the kiln inlet cover 110, so that the clay and the high-temperature flue gas flow in the opposite direction, and the exhaust gas is discharged from the exhaust port of the kiln inlet cover 110; this can maximize the heat energy transfer efficiency and ensure the best heat exchange effect of the material.

[0052] S30, controlling the temperature and flow of the high-temperature flue gas of the hot blast furnace 160, and controlling the temperature and flow of the waste heat recovery pipeline 248, wherein the high-temperature flue gas of the hot blast furnace 160 is maintained at 850°C-950°C, so that the activation temperature of the clay material is controlled at 800°C-850°C; ensuring that the material completes the activation reaction at a suitable temperature.

[0053] S40, control the heat exchange time of the clay material in the clay calcining rotary kiln 100 to complete the clay calcination after 60 to 120 minutes, and reach the kiln discharge cover 130; this time range can ensure that the material is fully heated and calcined, while avoiding excessive calcination that causes changes in the material properties. Because the cylinder is inclined, the clay is lifted to a certain height in the cylinder and then slides down and moves a distance along the axial lower end, forming an axial movement speed, and the clay is heated during the movement.

[0054] S50, control the reducing gas generator 170 to blow reducing gas at a temperature of 600°C to 800°C into the kiln discharge cover 130, so that the reducing gas reduces the reddish brown ferroferric oxide in the clay into black ferroferric oxide, and the reducing gas includes a specific concentration of carbon monoxide; thereby effectively controlling the color of the clay, avoiding the undesirable reddish brown color of the material, and obtaining a better black color. After reduction, the excess carbon monoxide gas enters the kiln and reacts with the oxygen in the high-temperature flue gas to generate carbon dioxide, and its waste heat is reused for calcining and drying the clay.

[0055] S60, control the first air-locking discharge valve 132 at the bottom of the kiln discharge cover 130 to discharge the clay material into the indirect heat exchange cooler 200. The cooled clay has a temperature lower than 120°C and is discharged through the second air-locking discharge valve 232 to obtain cement clinker. The first air-locking discharge valve 132 ensures normal discharge while preventing the high-temperature gas in the kiln discharge cover 130 from entering the cooler. The indirect heat exchange cooler 200 uses the heat exchange between the material and the cooling air to reduce the temperature of the material. The cylinder of the rotary cooler is inclined, and the material is lifted to a certain height in the cylinder and then slides down and moves a distance along the axial lower end at the same time, forming an axial movement speed. The cooled material falls from the cylinder into the cooler discharge cover and is discharged through the second air-locking discharge valve 232. The second air-locking discharge valve 232 ensures normal discharge while preventing air from entering the cooler.

[0056] After these steps, the obtained cement clinker meets the process requirements and has good quality and color. By controlling the concentration and temperature of the reducing gas, the color of the clay was successfully adjusted to achieve the desired effect.

[0057] The clay calcination and color control method in the embodiment of the present invention not only improves the energy efficiency of the calcination process, but also effectively controls the color of the material, ensuring the high quality and controllability of the final cement clinker through precise temperature and flow control, reasonable use of reducing gas and timely cooling treatment.

[0058] According to the clay calcination and color control system and method in the embodiment of the present invention, the beneficial effects that can be obtained include at least: (1) The present invention separates the drying section 121 and the calcining section 122 in the design of the rotary kiln, which are responsible for the drying and calcining processes of the materials respectively, ensuring that the process requirements of each stage are met. In the drying section 121, the clay material with high humidity will be quickly heated to remove moisture, while in the calcining section 122, the material is subjected to high temperature treatment to complete the chemical change. The rotary kiln is a continuous and uninterrupted production equipment that can stably and continuously process a large amount of clay materials. Its structural form can adapt to large-scale production, significantly improve production efficiency and capacity, and is particularly suitable for industrial applications that require large-scale continuous production.

[0059] (2) The present invention adjusts the drum speed of the rotary kiln through the speed regulating motor 141, thereby accurately controlling the residence time of the material in the kiln. This is crucial for the clay calcination process, because different types of clay (such as different hardness, humidity, etc.) have different heat exchange requirements during calcination. Adjusting the speed can achieve the best calcination effect for different clays, ensuring that the material obtains sufficient heat in the appropriate time, thereby improving the uniformity of calcination and product quality, while avoiding excessive or insufficient calcination.

[0060] (3) The present invention uses a hot blast furnace 160 as a heat source to calcine clay, and can accurately control the temperature of the hot flue gas entering the rotary kiln and maintain it in an ideal range (e.g., 850°C to 950°C). The use of the hot blast furnace 160 makes the flue gas temperature controllable, avoiding excessive temperatures and preventing high temperatures from adversely affecting the activity of the clay. Excessive temperatures may cause the clay material to be over-calcined, thereby affecting its chemical composition and physical properties, and further affecting the quality of the final product. Through the regulation of the hot blast furnace 160, the calcination effect of the clay is ensured to be more stable.

[0061] (4) The reducing gas generator 170 of the present invention generates reducing gas during the calcination process and injects it into the kiln to reduce the reddish brown iron sesquioxide ( ) is black ferroferric oxide ( ). This process not only helps control the color change of clay, but also improves the quality and appearance of clay. Through this reduction reaction, the undesirable color performance is reduced, ensuring that the appearance of the final cement clinker meets the needs of the market and users, and increasing the added value of the product.

[0062] (5) The rotary indirect heat exchange cooler 200 of the present invention adopts indirect heat exchange technology, that is, the cooling gas does not directly contact the clay material, but transfers energy through an air-cooled heat exchanger. This method can not only effectively reduce the temperature of the clay material (usually below 120°C), but also reduce the pollution or material quality fluctuations that may be caused by the contact between the material and the cooling medium. In addition, the indirect heat exchange method is safer and more reliable, avoiding material loss or pollution that may be caused by direct contact.

[0063] (6) Through the action of reducing gas, the iron oxide in the clay ( ) is reduced to ferroferric oxide ( ), thereby eliminating the reddish-brown effect and making the color of the clay more uniform and stable. This color control is very important for the appearance requirements of final products such as cement, avoiding the reddish-brown color of ferric oxide from having an adverse effect on the appearance of cement. This method can ensure the appearance quality of cement, meet industry standards and market demands, and enhance the market competitiveness of products.

[0064] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0065] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A clay calcination and color control system, characterized in that: The system comprises a clay calcining rotary kiln (100), a hot blast furnace (160), a reducing gas generator (170) and an indirect heat exchange cooler (200); The clay calcining rotary kiln (100) comprises a kiln inlet cover (110), a kiln body (120), a kiln outlet cover (130) and a first air-locking discharge valve (132); The kiln barrel (120) is arranged tilted, the kiln inlet cover (110) is arranged at a high end of the kiln barrel (120), and the kiln outlet cover (130) is arranged at a low end of the kiln barrel (120), so that clay material is fed into the clay calcining rotary kiln (100) at a high end, and the calcined clay material is discharged from a low end; The hot blast furnace (160) is connected to the kiln discharge cover (130) through a pipeline or directly, and the kiln inlet cover (110) has an exhaust gas port, so that the high-temperature flue gas provided by the hot blast furnace (160) enters the kiln body (120) at the lower end, and the exhaust gas is discharged from the higher end; The indirect heat exchange cooler (200) comprises a cooler feeding pipe (210), a cooler barrel (220) and a cooler kiln discharge cover (230); The first air-locking discharge valve (132) is arranged at the bottom of the kiln discharge cover (130), the cooler barrel (220) is arranged below the kiln discharge cover (130) and is connected to the first air-locking discharge valve (132) through a cooler feeding pipe (210) located at the front end thereof, and the cooler kiln discharge cover (230) is arranged at the end of the cooler barrel (220); The reducing gas generator (170) is arranged at the lower part of the kiln discharge cover (130) and is used to blow reducing gas into the kiln discharge cover (130) so as to cause reducing gas to react with the calcined clay and reduce the reddish brown ferric oxide to black ferrosirconium tetroxide.

2. The clay calcination and color control system according to claim 1, characterized in that: The kiln body (120) of the clay calcining rotary kiln (100) comprises a drying section (121) and a calcining section (122), and the angle of the kiln body (120) relative to the horizontal plane is set to 1° to 3°; Wherein, the inner wall of the drying section (121) is provided with a material lifting plate (123), and the material lifting plate (123) comprises a plurality of groups of inclined material lifting plates, L-shaped material lifting plates and arc-shaped material lifting plates arranged at intervals; The inner wall of the calcining section (122) is provided with a refractory layer (124).

3. The clay calcination and color control system according to claim 1, characterized in that: The clay calcining rotary kiln (100) further comprises a kiln transmission device (140), wherein the kiln transmission device (140) comprises a speed regulating motor (141), a reducer (142), a gear and a ring gear, wherein the speed regulating motor (141) is connected to the gear via the reducer (142), the ring gear is connected to the kiln body (120), and the gear is meshed with the ring gear; The clay calcining rotary kiln (100) further comprises a plurality of groups of kiln belts (151) and kiln support devices (152), wherein the kiln belts (151) are fixedly arranged on the outer peripheral wall of the kiln body (120), and the kiln support devices (152) are fixedly arranged on the bottom of the kiln body (120) for rotatably supporting the kiln belts (151).

4. The clay calcination and color control system according to claim 2, characterized in that: The hot blast furnace (160) is provided with a flue gas temperature control structure to control the high-temperature flue gas temperature of the calcining section (122) of the clay calcining rotary kiln (100) to be between 850°C and 950°C.

5. The clay calcination and color control system according to claim 1, characterized in that: The cooling machine barrel (220) of the indirect heat exchange cooling machine (200) is arranged tilted, and its angle relative to the horizontal plane is set to 1° to 3°; The cooler feeding pipe (210) is arranged at the upper end of the cooler barrel (220), and a cooler discharge cover is arranged at the lower end of the cooler barrel (220).

6. The clay calcination and color control system according to claim 5, characterized in that: A second air-locking discharge valve (232) is provided at the bottom of the cooler discharge cover, for preventing outside air from entering the cooler barrel (220) when the clay passes through the second air-locking discharge valve (232).

7. The clay calcination and color control system according to claim 5, characterized in that: The indirect heat exchange cooler (200) further comprises a blower (241), a cooling air inlet duct (242), a cooling air inlet cover (243), a cooling air duct (245), a cooler air outlet cover (246), and a waste heat recovery duct (248); The blower (241) is connected to the cooling air inlet hood (243) through the cooling air inlet duct (242), and the cooling air inlet hood (243) is arranged at the bottom end of the cooling machine barrel (220); A plurality of cooling air ducts (245) are provided, and are arranged inside the cooling machine barrel (220) along the axial direction thereof; inside the cooling machine barrel (220), the cooling air ducts (245) are sealed so that the cooling air does not contact the clay material; The heat recovery pipeline is arranged at the high end of the cooling machine barrel (220) and is connected to the cooling air pipeline (245).

8. The clay calcination and color control system according to claim 7, characterized in that: The cooling air absorbs the heat of the clay material in the cooling machine barrel (220) and is converted into high-temperature gas; The heat recovery pipeline is connected to the kiln discharge cover (130) to introduce the high-temperature flue gas provided by the hot blast furnace (160) that absorbs the high-temperature gas and mixes into the kiln body (120) of the clay calcining rotary kiln (100); The gas outlet of the heat recovery pipeline is located higher than the first air-locking discharge valve (132) and the reducing gas generator (170).

9. The clay calcination and color control system according to claim 5, characterized in that: The indirect heat exchange cooler (200) further comprises a cooler transmission device (260), wherein the cooler transmission device (260) comprises a reduction motor, a gear, and a gear ring, wherein the reduction motor is connected to the gear, the gear ring is connected to the cooler barrel (220), and the gear is meshed with the gear ring; The indirect heat exchange cooler (200) further comprises a plurality of sets of cooler wheel belts (251) and a cooler support device (252), wherein the cooler wheel belts (251) are fixedly arranged on the outer peripheral wall of the cooler barrel (220), and the cooler support device (252) is fixedly arranged on the bottom of the cooler barrel (220) for rotatably supporting the cooler wheel belts (251).

10. A method for calcining and controlling the color of clay, the method being implemented based on the clay calcining and color control system according to any one of claims 1 to 9, the method comprising the following steps: The interior of the clay calcining rotary kiln (100) is first preheated by high-temperature flue gas from a hot blast furnace (160), and a kiln driving device (140) is started to rotate the clay calcining rotary kiln (100); Feeding clay material into the clay calcining rotary kiln (100) through the kiln inlet cover (110) so that the clay and the high-temperature flue gas flow in the opposite direction, and the exhaust gas is discharged from the exhaust port of the kiln inlet cover (110); Controlling the temperature and flow rate of the high-temperature flue gas of the hot blast furnace (160), and controlling the temperature and flow rate of the waste heat recovery pipeline (248), wherein the high-temperature flue gas of the hot blast furnace (160) is maintained at 850° C. to 950° C., so that the activation temperature of the clay material is controlled at 800° C. to 850° C.; Controlling the heat exchange time of the clay material in the clay calcining rotary kiln (100) to be 60 to 120 minutes to complete the clay calcination and reach the kiln discharge cover (130); Controlling the reducing gas generator (170) to blow reducing gas at a temperature of 600°C to 800°C into the kiln discharge cover (130), so that the reducing gas reduces reddish brown ferrosoferric oxide in the clay into black ferrosoferric oxide, wherein the reducing gas includes carbon monoxide at a specific concentration; The first air-locking discharge valve (132) at the bottom of the kiln discharge cover (130) is controlled to discharge the clay material into the indirect heat exchange cooler (200). The cooled clay material has a temperature lower than 120° C. and is discharged through the second air-locking discharge valve (232) to obtain cement clinker.

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