Method and system for promoting settlement of sodium carbonate fine particles in sodium aluminate solution
By adding red mud slurry to the salt settling tank, the settling of fine sodium carbonate particles is improved, addressing mismixing issues and increasing production capacity and product quality in the Bayer process for aluminum oxide production.
Patent Information
- Application Number
- CN202510695504.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-28
- Publication Date
- 2025-07-15
AI Technical Summary
During the Bayer method of alumina production, the accumulation of impurities in the sodium aluminate solution leads to the refinement of sodium carbonate particles, resulting in the salt settlement tank running and mixing, poor settlement effect, low bottom flow solid content, lower production capacity of the salt discharge machine, and the fine sodium carbonate particles return to the alumina production system, affecting product quality and equipment efficiency.
Add red mud slurry to the salt sedimentation tank, and mix the red mud slurry with sodium aluminate solution to improve the sedimentation effect of the fine particles of sodium carbonate, and feed the salt sedimentation tank by washing the bottom flow pipeline assembly of the red mud wash the sedimentation tank.
It improves the settlement effect of the salt settlement tank, increases the bottom flow solid content, improves the production capacity of the salt discharge machine, reduces the return of fine sodium carbonate particles, improves the operation efficiency and product quality of the alumina production system, and has a simple structure and low cost.
Smart Images
Figure CN120308994A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of alumina production by the Bayer process, and particularly relates to a method for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution, and also relates to a system for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution. Background Art
[0002] In the salt removal process of alumina production by the Bayer process, due to the accumulation of impurities such as oxalate and sulfate in the sodium aluminate solution, the sodium carbonate particles precipitated by forced evaporation and salt removal are refined. The forced evaporation discharge enters the salt settling tank, resulting in the mixing of the salt settling tank. The sedimentation effect of the salt settling tank is poor, and the solid content of the underflow is low. The underflow of the salt settling tank is discharged to the salt removal machine, resulting in a decrease in the production capacity of the salt removal machine. The overflow of the salt settling tank enters the strong alkali tank, and the strong alkali liquid in the strong alkali tank returns to the alumina production system. The mixing of the salt settling tank will cause a large number of fine sodium carbonate particles to return to the alumina production system, which will further lead to the deterioration of the alumina production system, the deterioration of product quality, and the decline of equipment operation efficiency. Summary of the Invention
[0003] In view of this, one of the purposes of the present invention is to provide a method for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution to solve the technical problems proposed in the background art; the second purpose of the present invention is to provide a system for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution.
[0004] One of the purposes of the present invention is achieved through the following technical solutions:
[0005] A method for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution, adding red mud slurry to the salt settling tank, and the red mud slurry is mixed with the sodium aluminate solution to enhance the sedimentation effect of the fine sodium carbonate particles.
[0006] Further, the red mud slurry is the underflow of the red mud washing and settling tank.
[0007] Further, the red mud slurry is the underflow of the first washing settling tank or the last washing settling tank of the red mud washing and settling tank.
[0008] Further, the amount of red mud slurry added to the salt settling tank is 3-5 cubic meters per hour.
[0009] The second purpose of the present invention is achieved through the following technical solutions:
[0010] A system for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution, which includes a salt settling tank and a red mud washing and settling tank. A red mud slurry conveying pipeline assembly is connected to the underflow conveying pipe of the red mud washing and settling tank, and the discharge end of the red mud slurry conveying pipeline assembly is connected to the feed port of the salt settling tank.
[0011] Further, the red mud washing and settling tank is the underflow of the first washing settling tank or the last washing settling tank.
[0012] Further, the speed of the red mud slurry conveying pipeline assembly for conveying the red mud slurry is 3-5 cubic meters per hour.
[0013] Furthermore, the red mud slurry conveying pipeline assembly includes a red mud slurry conveying pipe, and a valve, a pump and a flow meter are sequentially arranged on the red mud slurry conveying pipe along the red mud slurry conveying direction.
[0014] Still further, a discharge pipe for discharging the red mud slurry to a trench is connected to the red mud slurry conveying pipe between the valve and the pump, and a discharge valve is connected to the discharge pipe.
[0015] The beneficial effects of the present invention are as follows:
[0016] The method for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution proposed in this embodiment adds red mud slurry to a salt sedimentation tank. The red mud slurry is the underflow of the first washing sedimentation tank or the underflow of the final washing sedimentation tank of the red mud washing sedimentation tank. The red mud slurry is mixed with the sodium aluminate solution to cause the fine sodium carbonate particles in the sodium aluminate solution to sediment. The sedimentation effect is obtained through a salt sedimentation performance experiment:
[0017] Salt sedimentation performance experiment 1: First, take the underflow of the first washing sedimentation tank of the red mud washing sedimentation tank as the red mud slurry for standby. Then, take 4 portions of sodium aluminate solution containing fine sodium carbonate particles in the salt sedimentation tank and place them in 4 reaction vessels respectively. The reaction vessels are graduated cylinders. The NK concentrations of the 4 portions of sodium aluminate solution containing fine sodium carbonate particles are 320 g / L respectively, the volumes are 500 ml respectively, and the temperatures are 95 °C respectively. Mark the experimental serial numbers 1, 2, 3, and 4 on the surfaces of the 4 reaction vessels respectively. Add 0 ml, 1 ml, 2 ml, and 3 ml of red mud slurry to the reaction vessels with experimental serial numbers 1, 2, 3, and 4 respectively. Observe the height of the clear liquid layer in the reaction vessels with experimental serial numbers 1, 2, 3, and 4 at 5 min and 10 min respectively. The results are shown in Table 1 and Figure 2 ( Figure 2 The upper side is the clear liquid layer):
[0018] Table 1 Salt sedimentation performance experiment 1
[0019]
[0020] Salt settlement performance experiment two: First, take the underflow of the final washing settlement tank in the red mud washing and settlement tank as the red mud slurry for standby. Then, take 4 portions of sodium aluminate solution containing fine sodium carbonate particles from the salt settlement tank and place them in 4 reaction vessels respectively. The reaction vessels are graduated cylinders. The NK concentrations of the 4 portions of sodium aluminate solution containing fine sodium carbonate particles are 320 g / L respectively, the volumes are 500 ml respectively, and the temperatures are 95 °C respectively. Mark the experiment serial numbers 1, 2, 3, and 4 on the surfaces of the 4 reaction vessels. Add 0 ml, 1 ml, 2 ml, and 3 ml of red mud slurry to the reaction vessels with experiment serial numbers 1, 2, 3, and 4 respectively. Observe the height of the clear liquid layer in the reaction vessels with experiment serial numbers 1, 2, 3, and 4 at 5 min and 10 min respectively. The results are shown in Table 2 and Figure 3 ( Figure 3 The upper side is the clear liquid layer):
[0021] Table 2 Salt settlement performance experiment two
[0022]
[0023] It can be seen from Table 1 and Table 2 that the mixing of red mud slurry and sodium aluminate solution can make the fine sodium carbonate particles in the sodium aluminate solution settle, and the settlement effect becomes better and better with the increase of the addition amount of red mud slurry. Therefore, the red mud slurry can improve the settlement effect of the fine sodium carbonate particles in the sodium aluminate solution. It solves the technical problems of a large amount of fine sodium carbonate particles returning to the alumina production system caused by the running and mixing of the salt settlement tank and the low solid content in the feed of the salt discharging machine resulting in the reduction of the production capacity of the salt discharging machine.
[0024] The system for improving the settlement of fine sodium carbonate particles in sodium aluminate solution proposed by the present invention improves the settlement effect of the fine sodium carbonate particles in the sodium aluminate solution, increases the solid content in the underflow of the salt settlement tank, improves the production capacity of the salt discharging machine, reduces the running and mixing of the salt settlement tank, reduces the return of fine sodium carbonate particles to the alumina production system, and has a simple structure and low cost. By setting a discharging pipe, it is used for discharging when the red mud slurry conveying pipeline assembly withdraws, such as during maintenance.
[0025] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following specification. Brief description of the drawings
[0026] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings, where:
[0027] Figure 1 is the schematic diagram of the present invention.
[0028] Figure 2 This is the experimental result graph of Experiment 1 on the salt sedimentation performance of the present invention.
[0029] Figure 3 This is the experimental result graph of Experiment 2 on the salt sedimentation performance of the present invention. Specific Embodiments
[0030] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the protection scope of the present invention.
[0031] Embodiment 1
[0032] As Figure 1-2 shown in the method for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution, red mud slurry is added to the salt sedimentation tank. The red mud slurry is the underflow of the first washing sedimentation tank or the underflow of the final washing sedimentation tank of the red mud washing and sedimentation tank. The red mud slurry is mixed with the sodium aluminate solution to enhance the sedimentation effect of fine sodium carbonate particles in the sodium aluminate solution. During actual production, the amount of red mud slurry added to the salt sedimentation tank is 3 - 5 cubic meters per hour.
[0033] In the method for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution proposed in this embodiment, red mud slurry is added to the salt sedimentation tank. The red mud slurry is the underflow of the first washing sedimentation tank or the underflow of the final washing sedimentation tank of the red mud washing and sedimentation tank. The red mud slurry is mixed with the sodium aluminate solution to cause the fine sodium carbonate particles in the sodium aluminate solution to sediment. The sedimentation effect is obtained through the salt sedimentation performance experiment:
[0034] Salt sedimentation performance experiment 1: First, take the underflow of the first washing sedimentation tank of the red mud washing and sedimentation tank as the red mud slurry for standby. Then, take 4 portions of sodium aluminate solution containing fine sodium carbonate particles in the salt sedimentation tank and place them in 4 reaction vessels respectively. The reaction vessels are measuring cylinders. The NK concentrations of the 4 portions of sodium aluminate solution containing fine sodium carbonate particles are 320 g / L respectively, the volumes are 500 ml respectively, and the temperatures are 95 °C respectively. Mark the experimental serial numbers 1, 2, 3, and 4 on the surfaces of the 4 reaction vessels respectively. Add 0 ml, 1 ml, 2 ml, and 3 ml of red mud slurry to the reaction vessels with experimental serial numbers 1, 2, 3, and 4 respectively. Observe the height of the clear liquid layer in the reaction vessels with experimental serial numbers 1, 2, 3, and 4 at 5 minutes and 10 minutes respectively. The results are shown in Table 1 and Figure 2 ( Figure 2 the upper side is the clear liquid layer):
[0035] Table 1 Salt sedimentation performance experiment 1
[0036]
[0037] Salt sedimentation performance experiment two: First, take the underflow of the final washing sedimentation tank in the red mud washing and sedimentation tank as the red mud slurry for standby. Then, take 4 portions of sodium aluminate solution containing fine sodium carbonate particles in the salt sedimentation tank and place them in 4 reaction vessels respectively. The reaction vessels are graduated cylinders. The NK concentrations of the 4 portions of sodium aluminate solution containing fine sodium carbonate particles are 320 g / L respectively, the volumes are 500 ml respectively, and the temperatures are 95 °C respectively. Mark the experimental serial numbers 1, 2, 3, and 4 on the surfaces of the 4 reaction vessels respectively. Add 0 ml, 1 ml, 2 ml, and 3 ml of red mud slurry to the reaction vessels with experimental serial numbers 1, 2, 3, and 4 respectively. Observe the height of the clear liquid layer in the reaction vessels with experimental serial numbers 1, 2, 3, and 4 at 5 min and 10 min respectively. The results are shown in Table 2 and Figure 3 ( Figure 3 the upper side is the clear liquid layer):
[0038] Table 2 Salt sedimentation performance experiment two
[0039]
[0040] From Table 1, Table 2, Figure 2 and Figure 3 it can be seen that the mixing of red mud slurry and sodium aluminate solution can make the fine sodium carbonate particles in the sodium aluminate solution sediment, and the sedimentation effect gets better and better with the increase of the addition amount of red mud slurry. Therefore, the red mud slurry can improve the sedimentation effect of the fine sodium carbonate particles in the sodium aluminate solution. It solves the technical problems of a large amount of fine sodium carbonate particles returning to the alumina production system caused by the mixing in the salt sedimentation tank and the decrease in the production capacity of the salt discharge machine due to the low solid content in the feed of the salt discharge machine.
[0041] Based on the salt sedimentation performance experiment, a causticization experiment is carried out. The specific method is as follows: Take 4 portions of sodium aluminate solution containing fine sodium carbonate particles in the salt sedimentation tank and place them in 4 reaction vessels respectively. The NK concentrations of the 4 portions of sodium aluminate solution containing fine sodium carbonate particles are 320 g / L respectively, the volumes are 500 ml respectively, and the temperatures are 95 °C respectively. Mark the experimental serial numbers 1, 2, 3, and 4 on the surfaces of the 4 reaction vessels respectively. Add 0 ml, 2 ml, 4 ml, and 6 ml of red mud slurry to the reaction vessels with experimental serial numbers 1, 2, 3, and 4 respectively. At 10 min, carry out solid-liquid separation on the solutions in the 4 reaction vessels in the form of making filter cakes to obtain four portions of solids. Add hot water to the four portions of solids respectively and mix them evenly to obtain the causticization stock solution. Then, carry out the causticization experiment. The causticization experiment method is the prior art and will not be elaborated here. The causticization results are shown in Table 3:
[0042] Table 3 Causticization experiment
[0043]
[0044] As can be seen from Table 3, as the addition amount of red mud slurry gradually increases, the causticization effect of sodium carbonate at the back end does not change significantly, indicating that after adding red mud slurry, it has no impact on the subsequent causticization.
[0045] Example 2
[0046] As Figure 1 The system for enhancing the settlement of fine sodium carbonate particles in sodium aluminate solution as shown, which includes a salt settling tank and a red mud washing and settling tank. A red mud slurry conveying pipeline assembly is connected to the underflow conveying pipe of the first washing settling tank or the final washing settling tank of the red mud washing and settling tank. The discharging end of the red mud slurry conveying pipeline assembly is connected to the feeding port of the salt settling tank. The speed of the red mud slurry conveying pipeline assembly for conveying red mud slurry is 3 - 5 cubic meters per hour. Specifically, the red mud slurry conveying pipeline assembly includes a red mud slurry conveying pipe 1. Along the red mud slurry conveying direction on the red mud slurry conveying pipe 1, a valve 2, a pump 3, and a flowmeter 4 are successively arranged. A discharging pipe 5 for discharging the red mud slurry to the trench is connected to the red mud slurry conveying pipe 1 between the valve 2 and the pump 3. A discharging valve 6 is connected to the discharging pipe 5.
[0047] The system for enhancing the settlement of fine sodium carbonate particles in sodium aluminate solution proposed by the present invention improves the settlement effect of fine sodium carbonate particles in sodium aluminate solution, increases the solid content of the underflow of the salt settling tank, improves the production capacity of the salt discharging machine, reduces the mixing of the salt settling tank, reduces the return of fine sodium carbonate particles to the alumina production system, and has a simple structure and low cost. By setting the discharging pipe 5, it is used to discharge the material to the trench when the red mud slurry conveying pipeline assembly is withdrawn, such as during maintenance.
[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered by the scope of the claims of the present invention.
Claims
1. A method for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution, characterized in that: Red mud slurry is added to the salt settling tank, and the red mud slurry is mixed with the sodium aluminate solution to enhance the settling effect of the fine particles of sodium carbonate in the sodium aluminate solution.
2. The method for enhancing the sedimentation of fine particles of sodium carbonate in sodium aluminate solution according to claim 1, characterized in that: The red mud slurry is the bottom flow of the red mud washing sedimentation tank.
3. The method for enhancing the sedimentation of fine particles of sodium carbonate in sodium aluminate solution according to claim 2, characterized in that: The red mud slurry is the bottom flow of the first wash sedimentation tank or the bottom flow of the final wash sedimentation tank of the red mud washing sedimentation tank.
4. The method for enhancing the sedimentation of fine particles of sodium carbonate in sodium aluminate solution according to any one of claims 1-3, characterized in that: The amount of red mud slurry added to the salt settling tank is 3-5 cubic meters per hour.
5. A system for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution, which comprises a salt sedimentation tank and a red mud washing and sedimentation tank, and is characterized in that: The underflow conveying pipe of the red mud washing and settling tank is connected with a red mud slurry conveying pipeline assembly, and the discharge end of the red mud slurry conveying pipeline assembly is connected to the feed port of the salt settling tank.
6. The system for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution according to claim 5, wherein: The red mud washing sedimentation tank is a first washing sedimentation tank bottom flow or a final washing sedimentation tank bottom flow.
7. The system for enhancing the sedimentation of fine sodium carbonate particles in sodium aluminate solution according to claim 5, characterized in that: The red mud slurry conveying pipeline assembly conveys red mud slurry at a speed of 3-5 cubic meters per hour.
8. The system for enhancing the sedimentation of fine particles of sodium carbonate in sodium aluminate solution according to any one of claims 5-7, characterized in that: The red mud slurry conveying pipeline assembly comprises a red mud slurry conveying pipe (1), on which a valve (2), a pump (3) and a flow meter (4) are sequentially arranged along the red mud slurry conveying direction.
9. The system for enhancing the sedimentation of fine particles of sodium carbonate in sodium aluminate solution according to any one of claims 8, characterized in that: A discharge pipe (5) for discharging the red mud slurry into a ditch is connected to the red mud slurry conveying pipe (1) between the valve (2) and the pump (3), and a discharge valve (6) is connected to the discharge pipe (5).