Red mud reduction furnace
Through the high-temperature calcination of red mud by two-stage rotary furnace, the problems of complex composition and unstable iron content are solved, and the effective utilization of red mud in cement production is achieved, the cement strength is improved and energy consumption and pollution are reduced.
Patent Information
- Application Number
- CN202422537002.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-21
- Publication Date
- 2025-08-29
- Estimated Expiration
- 2034-10-21
AI Technical Summary
The red mud has complex composition and unstable iron content, making it difficult to effectively utilize as an iron calibration material for cement, and the processing of the prior art is difficult.
A two-stage rotary furnace is used, including a preheating furnace and a calcining furnace. The iron oxide in the red mud is reduced to ferrous oxide or iron tetraoxide through high-temperature calcination, and the spiral propulsion teeth and the central gas supply structure are used to achieve efficient treatment of the red mud material.
The stable adjustment of the iron composition of red mud has been achieved, the early intensity development of cement clinker has been improved, and energy consumption and environmental pollution have been reduced.
Smart Images
Figure CN223283412U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of cement production, in particular to a roasting furnace, in particular to a device for calcining red mud as an iron correction material for cement. Background Art
[0002] my country has a large-scale aluminum industry, in which bauxite is used as raw material. The ore often contains a large amount of iron oxide. After aluminum smelting, these wastes containing iron oxide are called red mud or red mud because they are slightly red. Because red mud is strongly alkaline, has small particle size, is difficult to comprehensively utilize, has complex composition, and is difficult to develop and utilize, therefore, according to the scale of my country's aluminum industry, a large amount of red mud is generated every year and needs to be processed.
[0003] In cement production, iron is required for cement clinker, forming a special mineral phase such as tetracalcium aluminoferrite (C4AF), which contributes significantly to the early strength development of cement. Therefore, iron correction materials are added during the firing process to replenish and adjust the iron content in the cement clinker. Red mud has been found to contain a high level of iron, leading to the consideration of using it as an iron correction material for cement. However, due to its complex composition and the significant variations in the content of various components depending on the aluminum smelting process, red mud needs to be processed to achieve a stable iron content and a specific shape and structure for easy incorporation into cement clinker production. Utility Model Content
[0004] In order to address the deficiencies of the existing technology, the utility model proposes a red mud reduction furnace, which can reduce the iron oxide components in the red mud into ferrous oxide or ferroferric oxide through high-temperature calcination, making it convenient to adjust the iron content in the red mud to an appropriate range through subsequent treatment.
[0005] The technical problem to be solved by the present invention is achieved through the following technical solutions:
[0006] A red mud reduction furnace is a rotary furnace. In the utility model, it includes a preheating furnace and a calcining furnace which are concentrically arranged end to end. The furnace head of the preheating furnace is arranged to be an inwardly contracted opening, and a feed hopper and an air inlet pipe are arranged at the contracted opening. The furnace tail of the calcining furnace is provided with a discharge port, and a discharge hopper that matches the calcining furnace is arranged below the discharge port. Driving teeth surrounding the furnace body are provided on the outside of the preheating furnace and the calcining furnace. The driving teeth are driven by driving motors respectively, and the preheating furnace and the calcining furnace rotate synchronously.
[0007] In the present invention, the furnace walls of the preheating furnace and the calcining furnace are both multi-layer structures. The furnace walls of the preheating furnace are respectively composed of a preheating furnace outer layer, a preheating furnace insulation layer, and a preheating furnace inner layer from the outside to the inside, and spiral propulsion teeth are provided on the inner wall of the preheating furnace inner layer. The furnace walls of the calcining furnace are respectively composed of a calcining furnace outer layer, a calcining furnace insulation layer, and a calcining furnace inner layer from the outside to the inside, and spiral propulsion teeth are provided on the inner wall of the calcining furnace inner layer.
[0008] Furthermore, the inner diameter of the preheating furnace is smaller than the inner diameter of the calcining furnace. As the furnace body rotates, the material is directly pushed from the preheating furnace into the calcining furnace.
[0009] In the present invention, there is one air inlet pipe or a plurality of air inlet pipes arranged in parallel, and the air inlet pipes enter the preheating furnace from the furnace head of the preheating furnace and pass through the preheating furnace to reach the calcining furnace.
[0010] Furthermore, the air inlet pipe includes an outer pipe and an inner pipe, and the outer pipe and the inner pipe are fixed sleeve structures. The open end of the outer pipe is located in the preheating furnace, and the open end of the inner pipe is located in the calcining furnace. The cavity between the outer pipe and the inner pipe transports a mixture of combustion-supporting gas and inert gas, and the inner pipe transports a mixed flow of combustion medium and combustion-supporting gas. Specifically, the outer pipe and the inner pipe transport a mixture of oxygen and nitrogen, and the inner pipe transports a mixed flow of coal powder and oxygen.
[0011] In the present invention, the discharge port is a small window distributed in parallel around the tail of the calcining furnace. The small window penetrates the multi-layer structure of the calcining furnace. A shield is provided outside the discharge port to prevent heat and smoke from overflowing. The shield is a semi-enclosed structure with openings at the front and bottom. The front end of the shield is fitted with a gap between the outer wall of the calcining furnace. A smoke exhaust port is also provided at the tail of the calcining furnace, and the smoke exhaust port is connected to the outside of the shield.
[0012] Furthermore, the discharging hopper is located at the lower end of the discharging port, the upper part of the discharging hopper is arc-shaped, which matches the outer surface of the calcining furnace, and the left and right sides of the upper end of the discharging hopper are respectively matched with the gap of the furnace body on the left and right sides of the discharging port or rolled with the furnace body surface through rollers, and the lower part of the discharging hopper is funnel-shaped.
[0013] Furthermore, a material conveying device is provided directly below the discharge hopper to receive the material from the discharge hopper.
[0014] In the utility model, an ignition device and a temperature sensor are provided in both the preheating furnace and the calcining furnace.
[0015] In the present invention, the preheating furnace and the calcining furnace are arranged at an angle, and the center of the preheating furnace head is higher than the center of the calcining furnace tail.
[0016] Compared with the prior art, the utility model has the following advantages:
[0017] The present application processes the mixture of granulated red mud and reducing materials through a two-stage rotary kiln. The preheating furnace can further dry the red mud and heat and preliminarily ignite the reducing materials. The calcining furnace fully and controllably calcines the red mud and reducing materials, reducing part of the iron oxide in the red mud to ferrous oxide and ferroferric oxide, so that the iron content in the red mud can be adjusted to an appropriate content in subsequent steps such as magnetic separation.
[0018] The furnace head of the preheating furnace of the present application is provided with a constriction, and the furnace tail of the calcining furnace is provided with a shield, which can effectively realize the full utilization of heat by the entire furnace body and also prevent the emission of smoke from causing air pollution;
[0019] This application adopts the method of tilting the furnace body and screw pushing to push the material backward as the furnace body rotates until it reaches the discharge port;
[0020] This application adopts a central air supply method to effectively avoid the possibility of materials blocking the air inlet when the preheating furnace and the calcining furnace rotate. At the same time, the air supply sleeve structure avoids mutual interference between the preheating furnace and the calcining furnace when the air is supplied separately.
[0021] Therefore, the utility model has novel conception, ingenious design, good red mud treatment effect, energy saving and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a schematic diagram of the overall structure of the utility model;
[0023] Figure 2 for Figure 1 AA section view in the figure;
[0024] Figure 3 for Figure 1 BB section view in.
[0025] In the figure: feed hopper 1, feed hopper support frame 2, air inlet pipe 3, preheating furnace 4, calcining furnace 5, drive teeth 6, drive motor 7, discharge port 8, discharge hopper 9, rail trolley 10, smoke exhaust port 11, shield 12, preheating furnace outer layer 13, preheating furnace insulation layer 14, preheating furnace inner layer 15, spiral propulsion teeth 16, necking 17, feed pipe 18, outer tube 19, inner tube 20, calcining furnace outer layer 21, calcining furnace insulation layer 22, calcining furnace inner layer 23. DETAILED DESCRIPTION
[0026] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but the scope of protection of the present invention is not limited thereby.
[0027] A red mud reduction furnace, such as Figure 1As shown, it includes a preheating furnace 4 and a calcining furnace 5. The center of the furnace head of the preheating furnace 4 is set to an inward contraction 17. The tail of the preheating furnace 4 is concentrically connected to the furnace head of the calcining furnace 5. The tail of the preheating furnace 4 is provided with a discharge port 8. The preheating furnace 4 and the calcining furnace 5 are both provided with driving teeth 6 surrounding the furnace body. The driving teeth 6 are driven by driving motors 7 respectively. The preheating furnace 4 and the calcining furnace 5 rotate synchronously. The preheating furnace 4 and the calcining furnace 5 are arranged at an angle. The center of the furnace head of the preheating furnace 4 is higher than the center of the tail of the calcining furnace 5.
[0028] A feed hopper 1 and an air inlet pipe 3 are provided at the furnace head of the preheating furnace 4. The feed hopper 1 is located above the furnace head and is fixed by a feed hopper support frame 2. It receives the transported materials, which include red mud and reducing materials. The tail end of the feed hopper 1 is a feed pipe 18. The feed pipe 18 is inserted into the necking 17 and enters the preheating furnace 4. The air inlet pipe 3 also enters the preheating furnace 4 from the necking 17.
[0029] The discharge port 8 is a small window arranged in parallel around the tail of the calcining furnace 5. A discharge hopper 9 is provided directly below the discharge port 8. The upper part of the discharge hopper 9 is arc-shaped and matches the outer surface of the calcining furnace 5. The left and right sides of the upper end of the discharge hopper 9 respectively fit in the gap with the furnace body on the left and right sides of the discharge port 8 or roll with the furnace body surface through rollers. The lower part of the discharge hopper 9 is funnel-shaped. A rail trolley 10 is provided directly below the discharge hopper 9 to receive the material from the discharge hopper 9. A semi-enclosed structure shield 12 is provided outside the discharge port 8. The front end and lower part of the shield 12 are open. The front end of the shield 12 fits in the gap with the outer wall of the calcining furnace 5. A smoke exhaust port 11 is also provided at the tail of the calcining furnace 5. The smoke exhaust port 11 is connected to the outside of the shield 12.
[0030] exist Figure 2 and Figure 3 In the figure, the walls of both the preheating furnace 4 and the calcining furnace 5 are multi-layered. The walls of the preheating furnace 4, from outside to inside, consist of a preheating furnace outer layer 13, a preheating furnace insulation layer 14, and a preheating furnace inner layer 15. The inner wall of the preheating furnace inner layer 15 is provided with spiral propelling teeth 16. The feed pipe 18 and the air inlet pipe 3 are positioned in the middle of the preheating furnace 4 after passing through the necking 17. The walls of the calcining furnace 5, from outside to inside, consist of a calcining furnace outer layer 21, a calcining furnace insulation layer 22, and a calcining furnace inner layer 23. The inner wall of the calcining furnace inner layer 23 is provided with spiral propelling teeth 16. The inner diameter of the preheating furnace 4 is smaller than that of the calcining furnace 5. As the furnace body rotates, the material is pushed directly from the preheating furnace 4 into the calcining furnace 5.
[0031] like Figure 2The air inlet pipe 3 described in the figure comprises an outer tube 19 and an inner tube 20. The outer tube 19 and the inner tube 20 are of a sleeve structure. The inner tube 20 is located at the center of the outer tube 19. The outer tube 19 and the inner tube 20 are connected and fixed by connecting ribs. The open end of the outer tube 19 is located in the preheating furnace 4, and the open end of the inner tube 20 is located in the calcining furnace 5. The cavity between the outer tube 19 and the inner tube 20 transports a mixture of combustion-supporting gas and inert gas, and the inner tube 20 transports a mixed flow of combustion medium and combustion-supporting gas.
[0032] The utility model is applied to the preparation of silicate cement using red mud as an iron correction material. In the process flow, the red mud material after washing, dilution and pretreatment is dried and granulated by rollers in sequence to be made into granules or balls of appropriate size, which are then sent to the red mud reduction furnace of the utility model for reduction treatment. After crushing, grinding and magnetic separation, the red mud material with appropriate sodium, aluminum and iron components can be mixed with limestone and calcined and matured as cement raw material. Among them, in the reduction section of the present application, after the red mud material and the reducing material are fed into the feed hopper 1, they are evenly transported along the feed pipe 18 to the preheating furnace 4. With the assistance of the combustion-supporting gas fed into the air inlet pipe 3, part of the reducing material is ignited, and the red mud material and the reducing material are preheated and dried. With continuous tumbling, the red mud material is fed into the calcining furnace 5. Under the combustion and calcination of the combustion medium, the red mud material is heated to the reaction temperature and reacts with the reducing material and the reducing gas generated by the reducing material. The reacted red mud material passes through the discharge port 8 through the discharge hopper 9 into the rail trolley 10, and is continuously transported to the next process by the rail trolley 10.
[0033] In summary, combined with the above structure and use process, it can be found that the utility model has a novel concept, ingenious design, good red mud treatment effect, energy saving and environmental protection.
Claims
1. A red mud reduction furnace, which is a rotary furnace, characterized in that: It includes a preheating furnace and a calcining furnace which are concentrically connected end to end. The furnace head of the preheating furnace is set to be an inward-contracted opening, and a feed hopper and an air inlet pipe are set at the contracted opening. The furnace tail of the calcining furnace is provided with a discharge port, and a discharge hopper that matches the calcining furnace is set below the discharge port. Driving teeth surrounding the furnace body are set outside the preheating furnace and the calcining furnace. The driving teeth are driven by driving motors respectively, and the preheating furnace and the calcining furnace rotate synchronously.
2. The red mud reduction furnace according to claim 1, characterized in that: The furnace walls of the preheating furnace and the calcining furnace are both multi-layer structures. The furnace walls of the preheating furnace are respectively the outer layer of the preheating furnace, the thermal insulation layer of the preheating furnace, and the inner layer of the preheating furnace from the outside to the inside. The inner wall of the inner layer of the preheating furnace is provided with spiral propulsion teeth. The furnace walls of the calcining furnace are respectively the outer layer of the calcining furnace, the thermal insulation layer of the calcining furnace, and the inner layer of the calcining furnace from the outside to the inside. The inner wall of the inner layer of the calcining furnace is provided with spiral propulsion teeth.
3. The red mud reduction furnace according to claim 2, characterized in that: The inner diameter of the preheating furnace is smaller than the inner diameter of the calcining furnace.
4. The red mud reduction furnace according to claim 1, characterized in that: There is one air inlet pipe or a plurality of air inlet pipes arranged in parallel. The air inlet pipes enter the preheating furnace from the furnace head of the preheating furnace and pass through the preheating furnace to reach the calcining furnace.
5. The red mud reduction furnace according to claim 4, characterized in that: The air inlet pipe includes an outer pipe and an inner pipe, and the outer pipe and the inner pipe are fixed sleeve structures. The open end of the outer pipe is located in the preheating furnace, and the open end of the inner pipe is located in the calcining furnace. The cavity between the outer pipe and the inner pipe transports a mixture of combustion-supporting gas and inert gas, and the inner pipe transports a mixed flow of combustion medium and combustion-supporting gas.
6. The red mud reduction furnace according to claim 1, characterized in that: The discharge port is a small window distributed in parallel around the tail of the calcining furnace. The small window penetrates the multi-layer structure of the calcining furnace. A shield is provided outside the discharge port to prevent heat and smoke from overflowing. The shield is a semi-enclosed structure with openings at the front and bottom. The front end of the shield is fitted with a gap between the outer wall of the calcining furnace. A smoke exhaust port is also provided at the tail of the calcining furnace, and the smoke exhaust port is connected to the outside of the shield.
7. The red mud reduction furnace according to claim 6, characterized in that: The discharging hopper is located at the lower end of the discharging port, and the upper part of the discharging hopper is arc-shaped, which matches the outer surface of the calcining furnace. The left and right sides of the upper end of the discharging hopper respectively cooperate with the gap of the furnace body on the left and right sides of the discharging port or roll with the surface of the furnace body through rollers. The lower part of the discharging hopper is funnel-shaped.
8. The red mud reduction furnace according to claim 7, characterized in that: A material conveying device is provided directly below the discharge hopper.
9. The red mud reduction furnace according to claim 1, characterized in that: The preheating furnace and the calcining furnace are both provided with an ignition device and a temperature sensor.
10. The red mud reduction furnace according to claim 1, characterized in that: The preheating furnace and the calcining furnace are arranged tilted, and the center of the preheating furnace head is higher than the center of the calcining furnace tail.