A system for improving the sedimentation of fine sodium carbonate particles in sodium aluminate solution
By introducing a red mud slurry conveying pipeline assembly into the salt settling tank, the underflow of the red mud washing settling tank is mixed with the sodium aluminate solution, which solves the problem of poor sedimentation of sodium carbonate particles in the Bayer process, improves the sedimentation effect and the capacity of the salt discharge machine, and improves the operating efficiency and product quality of the alumina production system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUIZHOU HUAJIN ALUMINUM CO LTD
- Filing Date
- 2025-05-28
- Publication Date
- 2026-06-30
AI Technical Summary
In the Bayer process for alumina production, the accumulation of impurities in the sodium aluminate solution leads to the refinement of sodium carbonate particles, resulting in mixing in the salt settling tank, poor settling effect, low solids content in the underflow, reduced capacity of the salt discharge machine, and deterioration of product quality.
By introducing a red mud slurry conveying pipeline assembly into the salt settling tank, the underflow of the red mud washing settling tank is mixed with a sodium aluminate solution. The red mud slurry is used to enhance the settling effect of fine sodium carbonate particles and improve the settling performance.
It improved the settling effect of the salt settling tank, increased the solids content of the underflow, enhanced the capacity of the salt discharge machine, reduced the return of fine sodium carbonate particles to the alumina production system, improved product quality, and reduced costs.
Smart Images
Figure CN224430210U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of alumina production technology using the Bayer process, and in particular to a system for improving the sedimentation of fine sodium carbonate particles in sodium aluminate solution. Background Technology
[0002] In the Bayer process for alumina production, the accumulation of impurities such as oxalate and sulfate in the sodium aluminate solution leads to finer sodium carbonate particles precipitated during forced-efficiency evaporation. This precipitate enters the salt settling tank, causing turbidity and poor settling efficiency, resulting in low solids content in the underflow. The underflow from the salt settling tank is discharged to the desalting machine, reducing its capacity. Furthermore, the overflow from the salt settling tank enters the strong alkali tank, where the strong alkali solution is returned to the alumina production system. This turbidity in the salt settling tank causes a large amount of fine sodium carbonate particles to return to the alumina production system, further deteriorating the system, degrading product quality, and reducing equipment operating efficiency. Utility Model Content
[0003] In view of this, the purpose of this utility model is to provide a system for improving the sedimentation of fine sodium carbonate particles in sodium aluminate solution, so as to solve the technical problems mentioned in the background art.
[0004] The objective of this utility model is achieved through the following technical solution:
[0005] A system for improving the sedimentation of fine sodium carbonate particles in a sodium aluminate solution includes a salt sedimentation tank and a red mud washing sedimentation tank. A red mud slurry conveying pipeline assembly is connected to the underflow conveying pipe of the red mud washing sedimentation tank, and the discharge end of the red mud slurry conveying pipeline assembly is connected to the inlet of the salt sedimentation tank.
[0006] Furthermore, the red mud washing and settling tank is either the bottom flow of a first-wash settling tank or the bottom flow of a final-wash settling tank.
[0007] Furthermore, the red mud slurry conveying pipeline assembly conveys red mud slurry at a rate of 3-5 cubic meters per hour.
[0008] Furthermore, the red mud slurry conveying pipeline assembly includes a red mud slurry conveying pipe, on which valves, pumps, and flow meters are sequentially installed along the red mud slurry conveying direction.
[0009] Furthermore, a discharge pipe is connected to the red mud slurry conveying pipe between the valve and the pump, which can discharge the red mud slurry into the ditch, and a discharge valve is connected to the discharge pipe.
[0010] The beneficial effects of this utility model are:
[0011] The system for improving the sedimentation of fine sodium carbonate particles in sodium aluminate solution proposed in this invention transports the underflow from the first or last wash sedimentation tank of the red mud washing sedimentation tank to the salt sedimentation tank via a red mud slurry conveying pipeline assembly. In the salt sedimentation tank, the red mud slurry mixes with the sodium aluminate solution, causing the fine sodium carbonate particles in the sodium aluminate solution to settle. The sedimentation effect is obtained through salt sedimentation performance experiments.
[0012] Experiment 1 on salt settling performance: First, the bottom flow from the first settling tank of the red mud washing tank was used as red mud slurry for later use. Then, four portions of sodium aluminate solution containing fine sodium carbonate particles were taken from the salt settling tank and placed in four reaction containers (measuring cylinders). The NK concentrations of the four sodium aluminate solutions containing fine sodium carbonate particles were 320 g / L, the volumes were 500 ml, and the temperatures were 95℃. The four reaction containers were labeled with experiment numbers 1, 2, 3, and 4. 0 ml, 1 ml, 2 ml, and 3 ml of red mud slurry were added to reaction containers numbered 1, 2, 3, and 4, respectively. The height of the clear liquid layer in reaction containers numbered 1, 2, 3, and 4 was observed at 5 min and 10 min, respectively. The results are shown in Table 1.
[0013] Table 1
[0014]
[0015] Experiment 2 on salt settling performance: First, the bottom flow of the unwashed red mud settling tank was taken as red mud slurry for later use. Then, four portions of sodium aluminate solution containing fine sodium carbonate particles were taken from the salt settling tank and placed in four reaction containers (measuring cylinders). The NK concentrations of the four sodium aluminate solutions containing fine sodium carbonate particles were 320 g / L, the volumes were 500 ml, and the temperatures were 95℃. The experiment numbers 1, 2, 3, and 4 were marked on the surface of the four reaction containers. 0 ml, 1 ml, 2 ml, and 3 ml of red mud slurry were added to reaction containers numbered 1, 2, 3, and 4, respectively. The height of the clear liquid layer in reaction containers numbered 1, 2, 3, and 4 was observed at 5 min and 10 min, respectively. The results are shown in Table 2.
[0016] Table 2
[0017]
[0018] Tables 1 and 2 show that mixing red mud slurry with sodium aluminate solution can cause the fine sodium carbonate particles in the sodium aluminate solution to settle, and the settling effect becomes better with increasing red mud slurry addition. Therefore, red mud slurry can improve the settling effect of fine sodium carbonate particles in sodium aluminate solution. This solves the technical problems of a large amount of fine sodium carbonate particles returning to the alumina production system due to mixing in the salt settling tank and the reduced capacity of the salt dewatering machine due to low solids content in the feed.
[0019] The system for improving the sedimentation of fine sodium carbonate particles in sodium aluminate solution proposed in this invention enhances the sedimentation effect of fine sodium carbonate particles in sodium aluminate solution, increases the solids content in the bottom flow of the salt settling tank, improves the capacity of the salt discharge machine, reduces mixing in the salt settling tank, and reduces the return of fine sodium carbonate particles to the alumina production system. It has a simple structure and low cost. A discharge pipe is installed for discharging material when the red mud slurry conveying pipeline assembly is removed, such as during maintenance.
[0020] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description
[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the following will describe this utility model in further detail with reference to the accompanying drawings, wherein:
[0022] Figure 1 This is a schematic diagram of the present invention. Detailed Implementation
[0023] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the preferred embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.
[0024] Example 1
[0025] like Figure 1 The system shown is for the sedimentation of fine sodium carbonate particles in a sodium aluminate solution. It includes a salt sedimentation tank and a red mud washing sedimentation tank. A red mud slurry conveying pipeline assembly is connected to the underflow conveying pipe of the first or last washing sedimentation tank of the red mud washing sedimentation tank. The discharge end of the red mud slurry conveying pipeline assembly is connected to the inlet of the salt sedimentation tank. The red mud slurry conveying pipeline assembly conveys red mud slurry at a speed of 3-5 cubic meters per hour. Specifically, the red mud slurry conveying pipeline assembly includes a red mud slurry conveying pipe 1. A valve 2, a pump 3, and a flow meter 4 are sequentially installed on the red mud slurry conveying pipe 1 along the red mud slurry conveying direction. A discharge pipe 5 is connected to the red mud slurry conveying pipe 1 between the valve 2 and the pump 3, which can discharge the red mud slurry into a ditch. A discharge valve 6 is connected to the discharge pipe 5.
[0026] The system for improving the sedimentation of fine sodium carbonate particles in sodium aluminate solution proposed in this invention transports the underflow from the first or last wash sedimentation tank of the red mud washing sedimentation tank to the salt sedimentation tank via a red mud slurry conveying pipeline assembly. In the salt sedimentation tank, the red mud slurry mixes with the sodium aluminate solution, causing the fine sodium carbonate particles in the sodium aluminate solution to settle. The sedimentation effect is obtained through salt sedimentation performance experiments.
[0027] Experiment 1 on salt settling performance: First, the bottom flow from the first settling tank of the red mud washing tank was used as red mud slurry for later use. Then, four portions of sodium aluminate solution containing fine sodium carbonate particles were taken from the salt settling tank and placed in four reaction containers (measuring cylinders). The NK concentrations of the four sodium aluminate solutions containing fine sodium carbonate particles were 320 g / L, the volumes were 500 ml, and the temperatures were 95℃. The four reaction containers were labeled with experiment numbers 1, 2, 3, and 4. 0 ml, 1 ml, 2 ml, and 3 ml of red mud slurry were added to reaction containers numbered 1, 2, 3, and 4, respectively. The height of the clear liquid layer in reaction containers numbered 1, 2, 3, and 4 was observed at 5 min and 10 min, respectively. The results are shown in Table 1.
[0028] Table 1
[0029]
[0030] Experiment 2 on salt settling performance: First, the bottom flow of the unwashed red mud settling tank was taken as red mud slurry for later use. Then, four portions of sodium aluminate solution containing fine sodium carbonate particles were taken from the salt settling tank and placed in four reaction containers (measuring cylinders). The NK concentrations of the four sodium aluminate solutions containing fine sodium carbonate particles were 320 g / L, the volumes were 500 ml, and the temperatures were 95℃. The experiment numbers 1, 2, 3, and 4 were marked on the surface of the four reaction containers. 0 ml, 1 ml, 2 ml, and 3 ml of red mud slurry were added to reaction containers numbered 1, 2, 3, and 4, respectively. The height of the clear liquid layer in reaction containers numbered 1, 2, 3, and 4 was observed at 5 min and 10 min, respectively. The results are shown in Table 2.
[0031] Table 2
[0032]
[0033] Tables 1 and 2 show that mixing red mud slurry with sodium aluminate solution can cause the fine sodium carbonate particles in the sodium aluminate solution to settle, and the settling effect becomes better with increasing red mud slurry addition. Therefore, red mud slurry can improve the settling effect of fine sodium carbonate particles in sodium aluminate solution. This solves the technical problems of a large amount of fine sodium carbonate particles returning to the alumina production system due to mixing in the salt settling tank and the reduced capacity of the salt dewatering machine due to low solids content in the feed.
[0034] Based on the salt settling performance experiment, a causticization experiment was conducted. The specific method was as follows: Four portions of sodium aluminate solution containing fine sodium carbonate particles were placed in four reaction vessels in the salt settling tank. The NK concentrations of the four sodium aluminate solutions containing fine sodium carbonate particles were 320 g / L, the volumes were 500 ml, and the temperatures were 95℃. The reaction vessels were labeled with experiment numbers 1, 2, 3, and 4. 0 ml, 2 ml, 4 ml, and 6 ml of red mud slurry were added to reaction vessels numbered 1, 2, 3, and 4, respectively. After 10 minutes, the solutions in the four reaction vessels were separated into solid and liquid components by preparing filter cakes to obtain four solids. Hot water was then added to each of the four solids and mixed thoroughly to obtain the causticization stock solution. The causticization experiment was then conducted using existing technology, which will not be elaborated further here. The causticization results are shown in Table 3.
[0035] Table 3
[0036]
[0037] As shown in Table 3, as the amount of red mud slurry added gradually increases, the causticizing effect of sodium carbonate at the downstream end does not change significantly, indicating that the addition of red mud slurry has no effect on the downstream causticizing.
[0038] The system for improving the sedimentation of fine sodium carbonate particles in sodium aluminate solution proposed in this invention enhances the sedimentation effect of fine sodium carbonate particles in sodium aluminate solution, increases the solids content in the bottom flow of the salt settling tank, improves the capacity of the salt discharge machine, reduces mixing in the salt settling tank, and reduces the return of fine sodium carbonate particles to the alumina production system. It has a simple structure and low cost. A discharge pipe is installed for discharging material when the red mud slurry conveying pipeline assembly is removed, such as during maintenance.
[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of this technical solution, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.
Claims
1. A system for enhancing the settling of fine particles of sodium carbonate in a sodium aluminate solution, comprising a salt settling tank and a red mud wash settling tank, characterised in that: The bottom flow conveying pipe of the red mud washing and settling tank is connected with a red mud slurry conveying pipeline assembly, and the discharging end of the red mud slurry conveying pipeline assembly is connected with the feeding port of the salt settling tank.
2. The system for elevating the settling of fine sodium carbonate particles in a sodium aluminate solution according to claim 1, characterized in that: The red mud washing and settling tank is a washing and settling tank bottom flow or a final washing and settling tank bottom flow.
3. The system for elevating the settling of fine sodium carbonate particles in a sodium aluminate solution of claim 1, wherein: The speed of the red mud slurry conveying pipeline assembly in conveying red mud slurry is 3-5 cubic meters per hour.
4. The system for raising the settling of fine particles of sodium carbonate in a solution of sodium aluminate according to any one of claims 1-3, characterized in that: The red mud slurry conveying pipeline assembly comprises a red mud slurry conveying pipe (1), and a valve (2), a pump (3) and a flow meter (4) are sequentially arranged on the red mud slurry conveying pipe (1) along the red mud slurry conveying direction.
5. The system for elevating the settling of fine sodium carbonate particles in a sodium aluminate solution according to claim 4, characterized in that: A discharging pipe (5) for discharging red mud slurry to a ditch is connected to the red mud slurry conveying pipe (1) between the valve (2) and the pump (3), and a discharging valve (6) is connected to the discharging pipe (5).