Chromite oxidizing roasting device

Abstract

The utility model discloses a chromite oxidizing roasting device, which belongs to the technical field of metallurgical chemical equipment and comprises a first-section heating kiln, a second-section deep oxidation kiln, a chute and a support frame, the first-section heating kiln, the second-section deep oxidation kiln, the chute and the support frame are distributed in an up-and-down stepped manner, and the kiln heads of the first-section heating kiln and the second-section deep oxidation kiln are lower than the kiln tails and are inclined. According to the utility model, the sectional deep oxidizing roasting device is used for sectional oxidizing roasting, and the first-section heating kiln is mainly used for preheating raw materials and carrying out preliminary oxidizing roasting in the heating process; the second-section deep oxidation kiln is connected into an oxygen introducing pipeline, high-concentration oxygen gas is introduced into the kiln body, and deep oxidation roasting is carried out; meanwhile, when the oxygen hole is controlled to rotate to the bottom of the material, the controller opens the oxygen control valve of the corresponding access point, the material is exploded by means of the gas pressure of the oxygen, the contact area of the material and the oxygen is further increased along with rotation of the kiln body, and the mass and heat transfer effect is enhanced. The deep oxidation roasting device improves the chromium conversion rate, reduces the production cost and reduces the environmental pollution.

Description

Technical Field

[0001] This utility model belongs to the field of metallurgical and chemical equipment technology, and in particular relates to a chromite oxidation roasting device. Background Technology

[0002] Oxidative roasting of chromite is a key process in chromium salt production. Its main purpose is to convert chromium in chromite into soluble chromates for subsequent hydrometallurgical processing. Currently, the cleanest method for oxidative roasting of chromium salts is calcium-free roasting. Calcium-free roasting involves roasting chromite directly with soda ash in a rotary kiln without adding calcium filler. The advantages of this method are its simplicity and low energy consumption, but the chromium conversion rate is relatively low, typically only around 65%-80%.

[0003] In recent years, several improved roasting methods and apparatus have been proposed. Application number CN202111406536.X discloses a roasting method to improve the chromium-aluminum conversion rate of chromite. This method involves mixing chromite, sodium carbonate, and water, then heating the mixture with microwaves to precipitate sodium carbonate on the surface of the chromite. Subsequent oxygen-free and oxygen-enriched roasting further improves the chromium-aluminum conversion rate. However, this method requires additional microwave heating equipment and complex pretreatment processes, increasing production costs and operational complexity.

[0004] In addition, existing roasting equipment also has some problems in terms of oxygen supply and mass and heat transfer efficiency. For example, insufficient or uneven oxygen supply leads to incomplete oxidation reaction of chromite; the small contact area between the material and oxygen during roasting results in poor mass and heat transfer, low chromium conversion rate, large amount of chromium slag, and significant environmental pollution.

[0005] In summary, existing chromite oxidation roasting technology has the following main problems: low chromium conversion rate (the chromium conversion rate of ordinary roasting methods is usually only about 70%-80%), high energy consumption, high cost, and a lot of waste residue. Insufficient or uneven oxygen supply leads to incomplete oxidation reaction of chromite, affecting roasting effect. Poor mass and heat transfer, small contact area between material and oxygen, and uneven heat transfer affect roasting efficiency and product quality.

[0006] Based on this, the present invention designs a chromite oxidation roasting device to solve the above problems. Utility Model Content

[0007] The present invention aims to provide a segmented deep oxidation roasting device for chromite to improve chromium conversion rate, reduce coal consumption and chromium slag, and enhance mass and heat transfer.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A chromite oxidation roasting apparatus includes a primary heating kiln, a secondary deep oxidation kiln, a chute, a support frame, and an oxygen control valve, arranged in upper and lower steps. The kiln heads of the primary heating kiln and the secondary deep oxidation kiln are inclined below the kiln tails and are connected by the chute. Both the primary heating kiln and the secondary deep oxidation kiln are located above the support frame, and an oxygen generator is fixedly connected inside the support frame.

[0010] The kiln bodies of the first-stage heating kiln and the second-stage deep oxidation kiln have a refractory brick layer, an insulation layer, and a steel outer skin from the inside out. Kiln supports, kiln support rollers, and rotary wheels are installed on the outside of the kiln bodies of the first-stage heating kiln and the second-stage deep oxidation kiln in sequence at the kiln head, kiln tail, and middle parts.

[0011] The inclination of the kiln body of the first-stage heating kiln and the second-stage deep oxidation kiln is 0.5°-10°. Coal guns are installed at the kiln heads of the first-stage heating kiln and the second-stage deep oxidation kiln to feed coal into the rotary kiln respectively.

[0012] The first-stage heating kiln is equipped with a sample inlet and a negative pressure fan at its kiln tail, while the second-stage deep oxidation kiln is equipped with a discharge outlet at its kiln head.

[0013] As a further description of the above technical solution:

[0014] The bottom of the two-stage deep oxidation kiln is connected to an oxygen pipe, and oxygen holes are opened inside the kiln body. The oxygen holes are distributed in an equilateral triangle in the radial direction of the cylinder.

[0015] When the oxygen port rotates to the bottom of the material, the controller opens the oxygen control valve at the access point, and the material bursts open by the gas pressure of the oxygen.

[0016] As a further description of the above technical solution:

[0017] The first-stage heating kiln uses a PID control system to maintain the temperature at 700-1000℃, while the second-stage deep oxidation kiln uses a PID control system to maintain the temperature at 800-1200℃, based on the original temperature.

[0018] As a further description of the above technical solution:

[0019] The oxygen concentration at the tail end of the first-stage heating kiln is 3%-14%, the oxygen concentration at the tail end of the second-stage deep oxidation kiln is 16%-30%, the oxygen generator produces an oxygen concentration of 60%-85%, and the oxygen concentration is detected by a gas detector.

[0020] As a further description of the above technical solution:

[0021] The oxygen pipeline is connected to the oxygen generator.

[0022] As a further description of the above technical solution:

[0023] The oxygen generated by the oxygen generator enters the kiln body from the bottom of the rotary kiln material and reacts with the material.

[0024] As a further description of the above technical solution:

[0025] The first-stage heating kiln and the second-stage deep oxidation kiln are equipped with gas detectors for detecting oxygen concentration, and the oxygen concentration of the oxygen generator is controlled by an oxygen control valve to control its flow rate.

[0026] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0027] 1. In this invention, a segmented deep oxidation roasting device is used for segmented oxidation roasting. The first-stage heating kiln mainly performs preliminary oxidation roasting during the preheating and temperature rise of the raw materials. The second-stage deep oxidation kiln is connected to an oxygen supply pipe to introduce high-concentration oxygen gas into the kiln body for deep oxidation roasting. Simultaneously, when the oxygen orifice rotates to the bottom of the material, the controller opens the oxygen control valve at the corresponding access point, causing the material to burst open due to the gas pressure. The rotation of the kiln further increases the contact area between the material and oxygen, enhancing mass and heat transfer. This deep oxidation roasting device improves chromium conversion rate, reduces production costs, and reduces environmental pollution. Attached Figure Description

[0028] Figure 1 This is a three-dimensional structural schematic diagram of a chromite oxidation roasting device proposed in this utility model.

[0029] Figure 2 This is a three-dimensional structural diagram of an oxygen generator for a chromite oxidation roasting device proposed in this utility model;

[0030] Figure 3 This utility model proposes a chromite oxidation roasting device. Figure 2 Enlarged structural diagram of section A;

[0031] Figure 4 This is a schematic diagram of the cross-sectional structure of a two-stage deep oxidation kiln in a chromite oxidation roasting device proposed in this utility model.

[0032] Legend:

[0033] 1. Support frame; 2. First-stage heating kiln; 3. Negative pressure fan device; 4. Sample inlet; 5. Kiln support rollers; 6. Chute; 7. Second-stage deep oxidation kiln; 8. Discharge port; 9. Oxygen generator; 10. Oxygen pipeline; 11. Oxygen control valve; 12. Oxygen port. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0035] Please see Figures 1-4 ;

[0036] This utility model provides a technical solution: a chromite oxidation roasting device, comprising a primary heating kiln 2, a secondary deep oxidation kiln 7, a chute 6, a support frame 1, and an oxygen control valve 11, arranged in upper and lower steps. The kiln heads of the primary heating kiln 2 and the secondary deep oxidation kiln 7 are lower than the kiln tails and are inclined. The two are connected by the chute 6. Both the primary heating kiln 2 and the secondary deep oxidation kiln 7 are located above the support frame 1, and an oxygen generator 9 is fixedly connected inside the support frame 1.

[0037] The kiln bodies of the first-stage heating kiln 2 and the second-stage deep oxidation kiln 7 have a refractory brick layer, an insulation layer, and a steel outer skin from the inside out. The kiln supports, kiln support rollers 5, and rotary wheels are installed on the outside of the kiln bodies of the first-stage heating kiln 2 and the second-stage deep oxidation kiln 7 at the kiln head, kiln tail, and middle parts in sequence.

[0038] The inclination angles of the primary heating kiln 2 and the secondary deep oxidation kiln 7 are 0.5°-10°. Coal guns are installed at the kiln heads of the primary heating kiln 2 and the secondary deep oxidation kiln 7 to feed coal into the rotary kiln. The inclination angle of the kiln bodies of the primary heating kiln 2 and the secondary deep oxidation kiln 7 allows the kiln body to utilize gravity to guide the flow of materials, ensuring uniform movement of materials from the kiln head to the kiln tail. The installation of coal guns ensures that coal can be accurately fed into the kiln to participate in the heating and oxidation processes. The combination of these two aspects optimizes the contact effect between materials and fuel, improves heat transfer efficiency, and ensures that materials do not accumulate or stagnate during the roasting process, thereby improving production efficiency and energy utilization efficiency.

[0039] The first-stage heating kiln 2 has a sample inlet 4 and a negative pressure fan device 3 at the kiln tail, and the second-stage deep oxidation kiln 7 has a discharge outlet 8 at the kiln head.

[0040] The bottom of the two-stage deep oxidation kiln 7 is connected to an oxygen pipe 10, and oxygen holes 12 are opened inside the kiln body. The oxygen holes 12 are distributed in an equilateral triangle in the radial direction of the cylinder.

[0041] When the oxygen port 12 rotates to the bottom of the material, the controller opens the oxygen control valve 11 at the access point, and the material bursts open by the gas pressure of oxygen. The bottom of the two-stage deep oxidation kiln 7 is connected to an oxygen pipeline 10, and there is an oxygen port 12 inside. The oxygen control valve 11 is controlled by the controller. The configuration of the oxygen pipeline 10 ensures that oxygen can be stably supplied to the oxygen port 12 at the bottom of the kiln. The on / off control function of the oxygen control valve 11 makes the oxygen flow rate adjustment more precise. By precisely adjusting the oxygen flow rate through the control valve, it can be automatically adjusted according to the oxygen concentration and reaction requirements in the kiln, avoiding incomplete reactions caused by excessive or insufficient oxygen, improving the oxidation effect and chromium conversion rate, while reducing energy waste and pollution.

[0042] The temperature of the first-stage heating kiln 2 is controlled at 700-1000℃ by a PID control system. The temperature of the second-stage deep oxidation kiln 7 is controlled at 800-1200℃ by a PID control system on the basis of the original temperature. The oxygen concentration at the kiln tail of the first-stage heating kiln 2 is 3%-14%, and the oxygen concentration at the kiln tail of the second-stage deep oxidation kiln 7 is 16%-30%. The oxygen generator 9 produces an oxygen concentration of 60%-85%. The oxygen concentration is detected by a gas detector. The oxygen pipeline 10 is connected to the oxygen generator 9. The oxygen generated by the oxygen generator 9 enters the kiln body from the bottom of the rotary kiln material and reacts with the material. Gas detectors for detecting oxygen concentration are installed in the first-stage heating kiln 2 and the second-stage deep oxidation kiln 7. The oxygen concentration of the oxygen generator 9 is controlled by the oxygen control valve 11, which controls its flow rate.

[0043] During operation, chromite is fed into a primary heating kiln 21 and heated to 700-1000℃ for heating and pre-oxidation roasting. The heated chromite is then fed into a secondary deep oxidation kiln 72. Oxygen with a concentration of 65%-80% is generated by an oxygen generator 9 and introduced into the secondary deep oxidation kiln 72 via oxygen pipes 10 for deep oxidation of the chromite. Oxygen enters the kiln from the bottom of the rotary kiln and reacts with the material. The oxygen pipes 10 are arranged in an equilateral triangle, and oxygen is sprayed whenever the material is at the oxygen holes 12. Entering the kiln, the rotation of the kiln body increases the contact area between the material and oxygen, enhancing the mass and heat transfer effect. The oxygen concentration at the kiln tail of the first-stage heating kiln 2 is 3%-14%, and the oxygen concentration at the kiln tail of the second-stage deep oxidation kiln 7 is 16%-30%. The chromium conversion rate is increased from 75% to 95%-98%, the amount of chromium slag is reduced from 0.8t to 0.5t, and the coal consumption per ton of product is reduced from 0.75t to 0.45t. It has the advantages of good mass and heat transfer effect, high chromium conversion rate, low coal consumption, and reduced chromium slag.

[0044] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A chromite oxidation roasting device comprising a one-stage heating kiln (2), a two-stage deep oxidation kiln (7), a chute (6), a support frame (1) and an oxygen control valve (11) arranged in a ladder shape, characterized in that, The first heating kiln (2) and the second deep oxidation kiln (7) are inclined from the kiln head to the kiln tail, and are connected through a chute (6), the first heating kiln (2) and the second deep oxidation kiln (7) are arranged above a support frame (1), and the support frame (1) is fixedly connected with an oxygen generator (9); The kiln body of the first heating kiln (2) and the second deep oxidation kiln (7) is provided with, from inside to outside, a refractory brick layer, a heat preservation layer and a steel outer skin; and the kiln body of the first heating kiln (2) and the second deep oxidation kiln (7) is provided with, from outside to inside, a kiln head, a kiln tail and a middle part, a kiln support, a kiln support roller (5) and a rotating wheel; The inclination of the kiln body of the first heating kiln (2) and the second deep oxidation kiln (7) is 0.5°-10°, and the kiln head of the first heating kiln (2) and the second deep oxidation kiln (7) is provided with a coal gun for feeding coal into the rotary kiln; The kiln tail of the first heating kiln (2) is provided with a sample inlet (4) and a negative pressure fan device (3), and the kiln head of the second deep oxidation kiln (7) is provided with a discharge port (8).

2. A chromite oxidation roasting device according to claim 1, characterized in that, The second deep oxidation kiln (7) is connected with an oxygen pipeline (10) at the bottom, and the kiln body is provided with oxygen holes (12) in the inside, and the oxygen holes (12) are distributed in a regular triangle shape in the radial direction of the cylinder body; When the oxygen holes (12) rotate to the bottom of the material, the oxygen control valve (11) of the connection point is opened by the controller, and the material is exploded by the gas pressure of the oxygen.

3. A chromite oxidation roasting device according to claim 1, characterized in that, The temperature of the first heating kiln (2) is controlled to be 700-1000℃ through a PID control system, and the temperature of the second deep oxidation kiln (7) is controlled to be 800-1200℃ through a PID control system on the basis of the original temperature.

4. A chromite oxidation roasting device according to claim 1, characterized in that, The oxygen concentration at the kiln tail of the first heating kiln (2) is 3%-14%, the oxygen concentration at the kiln tail of the second deep oxidation kiln (7) is 16%-30%, and the oxygen concentration prepared by the oxygen generator (9) is 60%-85%.

5. A chromite oxidation roasting device according to claim 2, characterized in that, The oxygen pipeline (10) is connected with the oxygen generator (9).

6. A chromite oxidation roasting device according to claim 1, characterized in that, The oxygen generated by the oxygen generator (9) enters the inside of the kiln body from the bottom of the rotary kiln material and reacts with the material.

7. A chromite oxidation roasting device according to claim 2, characterized in that, The first heating kiln (2) and the second deep oxidation kiln (7) are provided with a gas detector for detecting the oxygen concentration, and the oxygen concentration of the oxygen generator (9) is controlled by the oxygen control valve (11).

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