High-pressure acid leaching apparatus having descaling function, and operating method thereof

Abstract

The present application relates to the technical field of high-pressure acid leaching apparatuses. Provided are a high-pressure acid leaching apparatus having a descaling function, and an operating method thereof. The high-pressure acid leaching apparatus comprises a pressure kettle, steam piping, and a descaling liquid intake bypass, wherein the steam piping is connected to the pressure kettle, and is configured to introduce high-pressure steam into the pressure kettle. The descaling liquid intake bypass is connected to the steam piping, and the descaling liquid intake bypass can introduce descaling liquid into the pressure kettle via the steam piping, so as to clean off at least part of the scale in the pressure kettle. The high-pressure acid leaching apparatus having a descaling function and the operating method thereof use the steam piping to perform descaling operations, such that the operating difficulty of the descaling operations and the cost of a descaling device can be reduced.

Description

High-pressure acid leaching equipment with scale removal function and working method thereof

[0001] The present application claims priority to the Chinese patent application No. 202411523642.X, filed on October 29, 2024, and entitled "High-pressure acid leaching equipment with scale removal function and working method thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of high-pressure acid leaching equipment, and particularly relates to a high-pressure acid leaching equipment with scale removal function and a working method thereof. BACKGROUND

[0003] In the production process of the high-pressure acid leaching equipment, most of the nickel and cobalt in the ore raw material (ore slurry) of the laterite nickel ore will dissolve into the solution, and most of the other impurities such as iron, silicon and aluminum in the ore raw material will remain in the slag, thereby realizing selective leaching of nickel and cobalt. Elements such as iron and aluminum in the laterite nickel ore are prone to form hematite and bauxite during high-pressure acid leaching, and scale is formed in the pressure kettle. The scale is easily attached to the surface of the stirring paddle in the pressure kettle, the inner wall of the pressure kettle and the inner wall of the discharge pipe. The accumulation of more scale can have a greater impact on the continuous operation of the high-pressure acid leaching equipment. In some production practices, the high-pressure acid leaching equipment used to treat laterite nickel ore with high aluminum content needs to be stopped for scale removal every 2 months on average. Frequent parking for scale removal can reduce the operation rate of the high-pressure acid leaching equipment and restrict the improvement of production capacity. SUMMARY

[0004] The present application is made in view of the above state of the art. The purpose of the present application is to provide a high-pressure acid leaching equipment with scale removal function, which uses at least part of the structure of the steam pipeline to introduce scale removal liquid into the pressure kettle, thereby reducing the difficulty of scale removal work and reducing the cost of scale removal device.

[0005] The present application also provides a working method of the above-mentioned high-pressure acid leaching equipment with scale removal function.

[0006] The present application provides a high-pressure acid leaching equipment with scale removal function, which comprises a pressure kettle, a steam pipeline and a scale removal liquid inlet bypass, the steam pipeline is connected to the pressure kettle and used to introduce high-pressure steam into the interior of the pressure kettle.

[0007] The scale removal liquid inlet bypass is connected to the steam pipeline, and the scale removal liquid inlet bypass can introduce scale removal liquid into the interior of the pressure kettle through at least part of the steam pipeline to clean at least part of the scale in the interior of the pressure kettle.

[0008] In at least one possible implementation, the composition of the descaling liquid includes sulfuric acid with a percentage concentration of 10% to 20% and ferric sulfate with a mass concentration of 0.5 to 1 gram per liter.

[0009] In at least one possible implementation, the pressurized kettle includes one or more stirring devices, the stirring devices including stirring paddles arranged inside the pressurized kettle,

[0010] The descaling liquid introduced into the interior of the pressurized kettle by the descaling liquid inlet bypass can clean at least part of the scale of at least one of the stirring paddles.

[0011] In at least one possible implementation, the high-pressure acid leaching device with a descaling function further includes a descaling control module, the descaling control module being capable of monitoring the working current of the stirring device to control the introduction of the descaling liquid into the interior of the pressurized kettle based on the size of the working current.

[0012] In at least one possible implementation, the pressurized kettle further includes one or more partitions, the partitions separating the interior of the pressurized kettle into multiple stirring areas,

[0013] The steam pipeline forms multiple branches, the multiple branches being respectively connected to different stirring areas to clean the scale of at least part of the stirring areas.

[0014] In at least one possible implementation, each of the branches is respectively connected to a different stirring area.

[0015] In at least one possible implementation, the descaling liquid inlet bypass is provided with an on-off valve for controlling the opening and closing of the descaling liquid inlet bypass; and / or

[0016] The steam pipeline is provided with a switching valve for controlling the communication between the descaling liquid inlet bypass and the steam pipeline.

[0017] The present application also provides a working method of a high-pressure acid leaching device with a descaling function, which is applied to the aforementioned high-pressure acid leaching device with a descaling function,

[0018] Before the descaling liquid introduced into the interior of the pressurized kettle by the descaling liquid inlet bypass, the high-pressure acid leaching device with a descaling function stops feeding, stops discharging, and stops introducing high-pressure steam.

[0019] In at least one possible implementation, the composition of the descaling liquid includes sulfuric acid with an percentage concentration of 10% to 20% and ferric sulfate with a mass concentration of0.5 to 1 gram per liter.

[0020] In at least one possible implementation, the temperature inside the pressure vessel is set to 170 to 200 degrees Celsius before the descaling solution is introduced into the pressure vessel via the descaling solution inlet bypass.

[0021] In at least one possible implementation, the high-pressure acid leaching equipment with descaling function further includes a descaling control module, which is capable of monitoring the operating current of the stirring device.

[0022] The descaling control module determines whether descaling is required based on the magnitude of the operating current of the stirring device, and / or

[0023] The descaling control module controls the descaling solution to be introduced into the pressure vessel through the descaling solution inlet bypass according to the operator's instructions.

[0024] In at least one possible implementation, the descaling control module stops supplying descaling solution into the pressure vessel after detecting that the operating current of the stirring device has returned to the normal range.

[0025] The high-pressure acid leaching equipment and its working method with descaling function provided in this application utilize a steam pipeline to introduce a descaling solution into the pressure vessel. This solution cleans at least a portion of the scale buildup inside the pressure vessel, particularly the scale coating the surface of the agitator within the pressure vessel, thereby reducing the adverse effects of scale buildup on the operation of the high-pressure acid leaching equipment. The descaling solution provided in this application utilizes the existing structure of the steam pipeline in the high-pressure acid leaching equipment, which can reduce the production and operating costs of the equipment and the difficulty of the descaling operation. Attached Figure Description

[0026] Figure 1 is a simplified structural diagram of a high-pressure acid leaching apparatus according to one embodiment of this application;

[0027] Figure 2 is a partial enlarged view of the simplified structural diagram shown in Figure 1.

[0028] Explanation of reference numerals in the attached drawings: 10-Pressure vessel; 11-Agitator; 111-Agitator paddle; 12-Baffle plate; 13-Discharge pipe; 20-Steam pipeline; 21-Branch; 30-Scaling solution inlet bypass; 40-Flash evaporator; 41-Downstream outlet; 50-Sulfuric acid pipeline; 60-Slag outlet; 70-Preheating device; 71-Slurry inlet; 72-Waste gas outlet. Detailed Implementation

[0029] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement this application only, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of this application.

[0030] The embodiments of this application provide a high-pressure acid leaching device (hereinafter, sometimes simply referred to as "high-pressure acid leaching device") with a descaling function, as shown in Figures 1 and 2. The high-pressure acid leaching device may include a pressure vessel 10, a steam pipeline 20, and a descaling liquid inlet bypass 30.

[0031] The ore slurry (especially laterite nickel ore slurry) can be preheated before entering the pressure vessel 10. The pressure vessel 10 can be supplied with high-pressure steam and sulfuric acid to meet the necessary conditions for the high-pressure acid leaching process. A steam pipeline 20 can be connected to the pressure vessel 10 to supply high-pressure steam into its interior. A descaling solution inlet bypass 30 can be connected to the steam pipeline 20 to supply descaling solution into the pressure vessel 10 via at least a portion of the steam pipeline 20. It is understood that utilizing at least a portion of the steam pipeline 20, compared to a separate descaling pipeline, can reduce the production cost of the high-pressure acid leaching equipment and decrease its space requirements.

[0032] The descaling solution may include sulfuric acid with a percentage concentration of 10% to 20% and ferric sulfate with a mass concentration of 0.5 to 1 gram per liter. The iron ions in the ferric sulfate can reduce the corrosion of the high-pressure acid leaching equipment by the descaling solution, especially the corrosion of the steam pipe 20 (which may be made of a titanium alloy containing iron).

[0033] The pressure vessel 10 may include one or more stirring devices 11, and the stirring device 11 may include a stirring paddle 111 disposed inside the pressure vessel 10. The surface of the stirring paddle 111, the inner surface of the pressure vessel 10, and the inner wall of the discharge pipe 13 of the pressure vessel are the main locations where scale easily forms in the pressure vessel 10. When there is a large amount of scale on the surface of the stirring paddle 111, the load on the stirring paddle increases, which in turn increases its operating current and affects the working state of the stirring paddle. The working state of the stirring paddle 111 has a significant impact on the production efficiency of the high-pressure acid leaching equipment. Furthermore, since the stirring paddle 111 is located inside the pressure vessel 10, it is difficult to directly clean the scale on its surface; often, it is necessary to disassemble the pressure vessel 10 to clean and replace the stirring paddle. In contrast, scale on the inner surface of the pressure vessel 10 has a smaller impact on the high-pressure acid leaching production operation; and the discharge pipe 13 of the pressure vessel 10 is easy to disassemble, and can be directly disassembled and replaced when there is a large amount of scale on the inner wall of the discharge pipe 13. After the descaling solution enters the pressurizing vessel 10, it can primarily clean the scale buildup on the surface of the agitator 111. Correspondingly, the end of the steam pipe 20 extending into the pressurizing vessel 10 can be close to the agitator 111. In particular, the end of the steam pipe 20 can be positioned above and relatively close to the agitator 111 to facilitate the cleaning solution cleaning the surface of the agitator 111.

[0034] The high-pressure acid leaching equipment may also include a descaling control module, which monitors the operating current of the agitator 11 (especially the agitator 111). When the operating current of the agitator 11 is too high (exceeding a certain range), it indicates that scale buildup on the surface of the agitator 111 may be affecting its normal operation. Based on the magnitude of the operating current of the agitator 11, the descaling control module can control the flow of descaling solution into the pressure vessel 10 via the descaling solution inlet bypass 30. When the operating current of the agitator 11 returns to the normal range, it indicates that the scale buildup on the surface of the agitator 111 has been effectively cleaned, and the flow of descaling solution into the pressure vessel 10 can be stopped, allowing normal high-pressure acid leaching production to resume.

[0035] Furthermore, the pressure vessel 10 may also include one or more baffles 12, which can divide the interior of the pressure vessel 10 into multiple stirring zones to improve the production efficiency of the high-pressure acid leaching operation. The liquid level of the slurry in the multiple stirring zones can gradually decrease from the feed end to the discharge end of the pressure vessel 10. For example, in Figures 1 and 2, the left end of the pressure vessel 10 is the feed end and the right end is the discharge end, and the liquid level of the slurry in the pressure vessel 10 can gradually decrease from the left end to the right end. The steam pipeline 20 can form multiple branches 21, which can be connected to different stirring zones respectively. The multiple branches 21 can respectively introduce descaling solution into the pressure vessel 10 to clean the scale in at least part of the stirring zones. Preferably, the number of branches 21 can be the same as the number of stirring zones, and each branch 21 can be connected to a different stirring zone respectively. At least one stirring device 11 can be provided in each stirring zone. For example, in Figures 1 and 2, the pressure vessel 10 is provided with four baffles 12, which divide the pressure vessel 10 into five stirring zones. The pressure vessel 10 is also provided with five stirring devices 11, one of which is installed in each stirring zone. Cleaning the interior of the pressure vessel 10 through multiple branch paths 21 improves the descaling effect and efficiency.

[0036] The descaling solution inlet bypass 30 may be equipped with a switch valve to control the on / off state of the descaling solution inlet bypass 30; and / or, the steam line 20 (especially at the junction of the steam line 20 and the descaling solution inlet bypass 30) may be equipped with a switching valve to control the connection between the descaling solution inlet bypass 30 and the steam line 20. The descaling solution inlet bypass 30 and / or the steam line 20 may also be equipped with flow meters to monitor the inlet flow rate of the descaling solution.

[0037] The pressure vessel 10 can also be equipped with an exhaust valve for cooling and depressurization. The exhaust valve can reduce the temperature and pressure inside the pressure vessel 10 before cleaning operations.

[0038] As shown in Figure 1, the high-pressure acid leaching equipment may further include a flash evaporation unit 40, a sulfuric acid pipeline 50, a slag outlet 60, and a preheating unit 70. The flash evaporation unit 40 is connected to the pressure vessel 10 via a discharge pipe 13. The slurry in the pressure vessel 10 can enter the flash evaporation unit 40 for flash evaporation. The flash evaporation unit 40 can be a multi-stage flash evaporation unit. The flash evaporation unit 40 may have a downstream outlet 41 to allow the flashed material to be fed into downstream process equipment. The sulfuric acid pipeline 50 can be connected to the pressure vessel 10 for introducing sulfuric acid into the pressure vessel 10 for high-pressure acid leaching. The slag outlet 60 can be connected to the pressure vessel 10 and / or the flash evaporation unit 40 for discharging the generated slag. The slag outlet 60 can be connected to the bottom of the pressure vessel 10 and / or the flash evaporation unit 40. The preheating unit 70 may have a slurry inlet 71 and be connected to the pressure vessel 10 to allow the slurry to be introduced and preheated before being fed back into the pressure vessel 10. The preheating device 70 can be a multi-stage preheating device. The preheating device 70 can also be connected to the flash evaporator 40 to preheat the slurry using flash gas. The preheating device 70 can also be equipped with an exhaust gas outlet to discharge waste gas generated during the preheating process, especially acidic waste gas.

[0039] The embodiments of this application also provide a method for operating a high-pressure acid leaching device with a descaling function, which can be applied to the aforementioned high-pressure acid leaching device.

[0040] Before introducing the descaling solution into the pressure vessel 10 through the descaling solution inlet bypass 30, the feeding, discharging, and high-pressure steam supply processes of the high-pressure acid leaching equipment can be stopped (the process of supplying sulfuric acid to the pressure vessel 10 via the sulfuric acid pipeline 50 can also be shut off), that is, the feed valve, discharge valve, and steam feed valve can be closed (the sulfuric acid feed valve can also be closed). Furthermore, the exhaust valve can be opened to reduce the temperature and pressure inside the pressure vessel 10. Before introducing the descaling solution into the pressure vessel 10, the temperature of the pressure vessel 10 can be reduced to 170 to 200 degrees Celsius. If the temperature is too high (above 200 degrees Celsius), the descaling solution may easily corrode the steam pipeline 20 and other devices inside the pressure vessel 10; if the temperature is too low (below 170 degrees Celsius), the slurry inside the pressure vessel 10 may more easily crystallize and form scale.

[0041] The descaling solution may include 10% to 20% sulfuric acid and 0.5 to 1 gram per liter ferric sulfate. This descaling solution is less likely to corrode steam pipes at temperatures between 170 and 200 degrees Celsius. Furthermore, the descaling solution dissolves scale more quickly at these temperatures, minimizing the impact of descaling operations on normal high-pressure acid leaching production. If the ambient temperature for descaling is too high (above 200 degrees Celsius), it may increase the tendency for hydrolysis (here, hydrolysis is the reverse reaction of the acidolysis of sulfuric acid with scale-forming substances such as ferric oxide), thereby inhibiting the decomposition rate of scale. If the ambient temperature for descaling is too low (below 170 degrees Celsius), the dissolution rate of scale will decrease due to the lower temperature. In summary, considering factors such as the corrosion of the steam pipeline 20 by the descaling solution and the dissolution rate of the scale, it is more appropriate to maintain the internal temperature of the pressure vessel 10 within the range of 170 to 200 degrees Celsius during the descaling operation (before starting the descaling operation). More preferably, the temperature of the pressure vessel 10 can be maintained at 200 degrees Celsius.

[0042] Below are comparative examples of several cleaning solutions with different ingredients:

[0043] Comparative Example 1

[0044] The descaling solution provided in this application consists of sulfuric acid with a percentage concentration of 10% to 20% and ferric sulfate with a mass concentration of 0.5 to 1 gram per liter. Its corrosion rate on steam pipeline samples in an environment of 200 degrees Celsius is 0.01 to 0.02 mm / a (millimeters per year).

[0045] Comparative Example 2

[0046] The composition is sulfuric acid with a percentage concentration of 10% to 20%. Its corrosion rate on steam pipeline samples in an environment of 200 degrees Celsius is 90 to 120 mm / a (millimeters per year).

[0047] Comparative Example 3

[0048] The composition is hydrochloric acid with a percentage concentration of 10% to 20%. It completely dissolves the steam pipeline sample in an environment of 200 degrees Celsius.

[0049] In summary, the descaling solution provided by the embodiments of this application has a weak corrosive effect on steam pipelines at a temperature of 200 degrees Celsius, and is suitable for transportation through steam pipeline 20.

[0050] The descaling control module can determine whether descaling is necessary based on the operating current of the agitator it monitors, and can provide feedback on its monitoring and judgment results to the operator. The descaling control module can automatically or, based on operator instructions, control the high-pressure acid leaching equipment to perform descaling operations.

[0051] Furthermore, when the scale removal control module detects that the current of the stirring device has returned to the normal current range, that is, the scale on the stirring paddle 111 has been cleaned to the point that it does not affect the normal operation of the stirring paddle 111, the flow of scale removal liquid into the pressure vessel 10 can be stopped, and / or the scale removal control module can provide relevant information to the operator to end the scale removal operation in a timely manner.

[0052] The following is a brief description of some of the beneficial effects of the above-described embodiments of this application.

[0053] The high-pressure acid leaching equipment and its operating method with descaling function provided in this application utilize a steam pipeline to introduce a descaling solution into a pressure vessel. This solution cleans at least a portion of the scale buildup inside the pressure vessel, particularly reducing scale buildup on the surface of the agitator within the pressure vessel, thereby minimizing the adverse effects of scale buildup on the operation of the high-pressure acid leaching equipment. The descaling solution provided in this application utilizes the existing structure of the steam pipeline in the high-pressure acid leaching equipment, reducing production and operating costs and simplifying the process. Furthermore, this application provides the composition of the descaling solution suitable for this high-pressure acid leaching equipment and its appropriate ambient temperature range. Using the descaling solution within the appropriate temperature range effectively reduces the corrosion of the steam pipeline by the acidic descaling solution and maintains a relatively fast scale dissolution rate. This embodiment allows for automatic or manual control of the descaling operation of the high-pressure acid leaching equipment via a descaling control module, meeting the flexible control requirements of actual production.

[0054] It is understood that, in this application, when the number of parts or components is not specifically limited, the number can be one or more, where multiple refers to two or more. For cases where the number of parts or components shown in the drawings and / or described in the specification is, for example, two, three, four, etc., this specific number is generally exemplary and not restrictive, and can be understood as multiple, i.e., two or more; however, this does not mean that this application excludes the case of one.

[0055] It should be understood that the above embodiments are merely exemplary and are not intended to limit this application. Those skilled in the art can make various modifications and changes to the above embodiments under the teachings of this application without departing from the scope of this application.

Claims

1. A high-pressure acid leaching device with descaling function, characterized in that, It includes a pressure vessel (10), a steam pipeline (20), and a descaling solution inlet bypass (30). The steam pipeline (20) is connected to the pressure vessel (10) and is used to introduce high-pressure steam into the interior of the pressure vessel (10). The descaling liquid inlet bypass (30) is connected to the steam pipeline (20), and the descaling liquid inlet bypass (30) can introduce descaling liquid into the interior of the pressure vessel (10) via at least a portion of the steam pipeline (20) to clean at least a portion of the scale inside the pressure vessel (10).

2. The high-pressure acid leaching equipment with descaling function according to claim 1, characterized in that, The cleaning solution comprises sulfuric acid at a percentage concentration of 10% to 20% and ferric sulfate at a mass concentration of 0.5 to 1 gram per liter.

3. The high-pressure acid leaching equipment with descaling function according to claim 1, characterized in that, The pressure vessel (10) includes one or more stirring devices (11), each stirring device (11) including a stirring paddle (111) disposed inside the pressure vessel (10). The descaling solution introduced into the interior of the pressurized vessel (10) through the descaling solution inlet bypass (30) is capable of cleaning at least a portion of the scale on at least one of the stirring paddles (111).

4. The high-pressure acid leaching equipment with descaling function according to claim 3, characterized in that, It also includes a descaling control module, which can monitor the operating current of the stirring device (11) and control the descaling liquid inlet bypass (30) to introduce descaling liquid into the interior of the pressurizing vessel (10) based on the magnitude of the operating current.

5. The high-pressure acid leaching equipment with descaling function according to any one of claims 1 to 4, characterized in that, The pressure vessel (10) also includes one or more partitions (12), which divide the interior of the pressure vessel (10) into multiple stirring zones. The steam pipe (20) forms multiple branches (21), which are respectively connected to different stirring zones to clean scale in at least part of the stirring zones.

6. The high-pressure acid leaching equipment with descaling function according to claim 5, characterized in that, The number of branch paths (21) is the same as the number of stirring zones. Each of the branch paths (21) is connected to a different mixing zone.

7. The high-pressure acid leaching equipment with descaling function according to claim 1, characterized in that, The descaling solution inlet bypass (30) is equipped with a switch valve to control the opening and closing of the descaling solution inlet bypass (30); and / or The steam pipeline (20) is equipped with a switching valve to control the connection between the descaling liquid inlet bypass (30) and the steam pipeline (20).

8. A method for operating a high-pressure acid leaching device with descaling function, characterized in that, The high-pressure acid leaching equipment with descaling function is the same as the high-pressure acid leaching equipment with descaling function according to any one of claims 1 to 7. Before the descaling liquid is introduced into the pressure vessel (10) through the descaling liquid inlet bypass (30), the high-pressure acid leaching equipment with descaling function stops feeding, stops discharging, and stops introducing high-pressure steam.

9. The working method of the high-pressure acid leaching equipment with descaling function according to claim 8, characterized in that, The cleaning solution comprises sulfuric acid at a percentage concentration of 10% to 20% and ferric sulfate at a mass concentration of 0.5 to 1 gram per liter.

10. The working method of the high-pressure acid leaching equipment with descaling function according to claim 8, characterized in that, Before the descaling liquid is introduced into the pressure vessel (10) through the descaling liquid inlet bypass (30), the temperature inside the pressure vessel (10) is set to 170 to 200 degrees Celsius.

11. The working method of the high-pressure acid leaching equipment with descaling function according to claim 8, characterized in that, The high-pressure acid leaching equipment with descaling function is the high-pressure acid leaching equipment with descaling function as described in claim 4. The descaling control module determines whether descaling is required based on the magnitude of the operating current of the stirring device (11), and / or The descaling control module controls the descaling liquid inlet bypass (30) to introduce descaling liquid into the pressure vessel (10) according to the operator's instructions.

12. The working method of the high-pressure acid leaching equipment with descaling function according to claim 11, characterized in that, After the scale removal control module detects that the working current of the stirring device (11) has returned to the normal range, it stops feeding scale removal liquid into the pressure vessel (10).

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