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

Abstract

According to the high-pressure acid leaching equipment with the scale removing function and the working method thereof, the high-pressure acid leaching equipment comprises an autoclave, a steam pipeline and a scale removing liquid inlet bypass, and the steam pipeline is connected with the autoclave and used for introducing high-pressure steam into the autoclave. The scale cleaning liquid inlet bypass is connected with the steam pipeline, and the scale cleaning liquid inlet bypass can introduce scale cleaning liquid into the autoclave through the steam pipeline so as to clean at least part of scales in the autoclave. According to the high-pressure acid leaching equipment with the scale cleaning function and the working method thereof, the scale cleaning operation is carried out by utilizing the steam pipeline, the working difficulty of the scale cleaning operation can be reduced, and the cost of the scale cleaning device is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of high-pressure acid leaching equipment, and in particular to a high-pressure acid leaching equipment with a descaling function and a working method thereof. Background Art

[0002] During the production process of high-pressure acid leaching equipment, most of the nickel and cobalt in the ore raw material (slurry) of laterite nickel ore will dissolve into the solution, while most of the other impurities such as iron, silicon and aluminum in the ore raw material will remain in the slag, thereby achieving selective leaching of nickel and cobalt. Elements such as iron and aluminum in laterite nickel ore are prone to generate hematite and alum during high-pressure acid leaching, forming scale in the autoclave. The scale is easy to adhere to the surface of the stirring blades in the autoclave, the inner wall of the autoclave and the inner wall of the discharge pipe. More scale accumulation can easily have a significant impact on the continuous operation of the high-pressure acid leaching equipment. In some production practices, the autoclave of the high-pressure acid leaching equipment used to process laterite nickel ore with a high aluminum content needs to be stopped every 2 months on average for descaling operations. Frequent shutdowns for descaling will reduce the operating rate of the high-pressure acid leaching equipment and restrict the improvement of production capacity. Summary of the invention

[0003] This application is made in view of the above-mentioned state of the prior art. The purpose of this application is to provide a high-pressure acid leaching device with a descaling function, which uses at least part of the structure of the steam pipeline to pass descaling liquid into the pressure kettle, which can reduce the difficulty of descaling work and reduce the cost of the descaling device.

[0004] The present application also provides a working method of the above-mentioned high-pressure acid leaching equipment with scale removal function.

[0005] The present application provides a high-pressure acid leaching device with a descaling function, which comprises a pressure kettle, a steam pipeline and a descaling liquid inlet bypass, wherein the steam pipeline is connected to the pressure kettle and is used to pass high-pressure steam into the interior of the pressure kettle.

[0006] The descaling liquid inlet bypass is connected to the steam pipeline, and the descaling liquid inlet bypass can pass descaling liquid into the interior of the autoclave through at least a portion of the steam pipeline to clean at least a portion of the scale inside the autoclave.

[0007] In at least one possible embodiment, the descaling liquid comprises sulfuric acid with a percentage concentration of 10% to 20% and iron sulfate with a mass concentration of 0.5 to 1 gram per liter.

[0008] In at least one possible embodiment, the autoclave includes one or more stirring devices, and the stirring device includes a stirring paddle disposed inside the autoclave.

[0009] The descaling liquid introduced into the interior of the autoclave through the descaling liquid inlet bypass can clean at least part of the scale on at least one of the stirring blades.

[0010] In at least one possible embodiment, the high-pressure acid leaching equipment with a descaling function further includes a descaling control module, which is capable of monitoring the working current of the stirring device to control the descaling liquid inlet bypass to pass the descaling liquid into the interior of the pressure kettle based on the magnitude of the working current.

[0011] In at least one possible embodiment, the autoclave further includes one or more partitions, which divide the interior of the autoclave into a plurality of stirring zones.

[0012] The steam pipeline forms a plurality of branches, and the plurality of branches are respectively connected to different stirring zones to clean scales in at least part of the stirring zones.

[0013] In at least one possible implementation manner, each of the branches is respectively connected to a different stirring area.

[0014] In at least one possible implementation, the descaling liquid inlet bypass is provided with a switch valve for controlling the on-off of the descaling liquid inlet bypass; and / or

[0015] The steam pipeline is provided with a switching valve for controlling the communication between the descaling liquid inlet bypass and the steam pipeline.

[0016] The present application also provides a working method of a high-pressure acid leaching device with a descaling function, which is applied to the above-mentioned high-pressure acid leaching device with a descaling function.

[0017] Before the descaling liquid inlet bypass is passed into the interior of the autoclave, the high-pressure acid leaching equipment with descaling function stops feeding, discharging, and passing high-pressure steam.

[0018] In at least one possible embodiment, the descaling liquid comprises sulfuric acid with a percentage concentration of 10% to 20% and iron sulfate with a mass concentration of 0.5 to 1 gram per liter.

[0019] In at least one possible embodiment, before the descaling liquid inlet bypass is passed into the interior of the autoclave, the temperature in the autoclave is set to 170 to 200 degrees Celsius.

[0020] In at least one possible embodiment, the high-pressure acid leaching equipment with a descaling function further includes a descaling control module, wherein the descaling control module is capable of monitoring the working current of the stirring device.

[0021] The descaling control module determines whether descaling is required based on the magnitude of the working current of the stirring device, and / or

[0022] The descaling control module controls the descaling liquid inlet bypass to introduce descaling liquid into the autoclave according to the operator's instruction.

[0023] In at least one possible implementation, after the descaling control module detects that the working current of the stirring device returns to a normal range, the descaling control module stops introducing the descaling liquid into the autoclave.

[0024] The high-pressure acid leaching equipment with a descaling function and the working method thereof provided by the present application use a steam pipeline to introduce a descaling liquid into the pressure vessel, and use the descaling liquid to clean at least part of the scale in the pressure vessel, especially the scale wrapped on the surface of the stirring paddle in the pressure vessel, thereby reducing the adverse effect of the scale on the operation of the high-pressure acid leaching equipment. The descaling scheme provided by the present application utilizes the existing structure of the steam pipeline of the high-pressure acid leaching equipment, which can reduce the production and operation costs of the equipment and the difficulty of the descaling operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a simplified structural diagram of a high-pressure acid leaching device according to one embodiment of the present application.

[0026] Figure 2 for Figure 1 A partial enlarged view of the structural diagram shown.

[0027] Description of Reference Numerals

[0028] 10. Autoclave

[0029] 11. Stirring device

[0030] 111 stirring paddle

[0031] 12. Partition

[0032] 13 Discharge pipe

[0033] 20 Steam pipeline

[0034] 21 Branch Road

[0035] 30 Descaling liquid inlet bypass

[0036] 40 Flash evaporation unit

[0037] 41 Downstream outlet

[0038] 50 Sulfuric acid pipeline

[0039] 60 Slag outlet

[0040] 70 Preheating device

[0041] 71 Slurry inlet

[0042] 72 Exhaust gas outlet DETAILED DESCRIPTION

[0043] The exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all possible methods of the present application, nor to limit the scope of the present application.

[0044] The embodiment of the present application provides a high pressure acid leaching device with a descaling function (hereinafter, sometimes referred to as "high pressure acid leaching device"), such as Figure 1 and Figure 2 As shown, the high-pressure acid leaching equipment may include a pressure reactor 10 , a steam pipeline 20 and a descaling liquid inlet bypass 30 .

[0045] The ore slurry (especially laterite nickel ore slurry) can enter the autoclave 10 after preheating, and the autoclave 10 can be fed with high-pressure steam and sulfuric acid to meet the necessary conditions of the high-pressure acid leaching process. The steam pipeline 20 can be connected to the autoclave 10 to pass high-pressure steam into the interior of the autoclave 10. The descaling liquid inlet bypass 30 can be connected to the steam pipeline 20 to pass the descaling liquid into the interior of the autoclave 10 through at least a portion of the steam pipeline 20. It can be understood that using at least a portion of the pipeline structure of the steam pipeline 20 can reduce the production cost of the high-pressure acid leaching equipment and reduce the occupied space of the high-pressure acid leaching equipment compared to setting up a descaling pipeline separately.

[0046] The descaling liquid may include sulfuric acid with a percentage concentration of 10% to 20% and ferric sulfate with a mass concentration of 0.5 to 1 g / L. The iron ions in the ferric sulfate can reduce the corrosion of the descaling liquid to the high-pressure acid leaching equipment, especially the corrosion of the descaling liquid to the steam pipeline 20 (the steam pipeline 20 can be made of a titanium alloy containing iron elements).

[0047] The autoclave 10 may include one or more stirring devices 11, and the stirring device 11 may include a stirring paddle 111 disposed inside the autoclave 10. The surface of the stirring paddle 111, the inner surface of the autoclave 10, and the inner wall of the discharge pipe 13 of the autoclave are the main locations where the autoclave 10 is prone to scale formation. Among them, when there is a lot of scale on the surface of the stirring paddle 111, the load of the stirring paddle will increase, thereby increasing its working current and affecting the working state of the stirring paddle. The working state of the stirring paddle 111 has a great influence on the production efficiency of the high-pressure acid leaching equipment, and the stirring paddle 111 is located inside the autoclave 10, and it is difficult to directly clean the scale on its surface. It is often necessary to disassemble the autoclave 10 to clean and replace the stirring paddle. In contrast, the scale on the inner surface of the autoclave 10 has little effect on the high-pressure acid leaching production operation; and the discharge pipe 13 of the autoclave 10 is easy to disassemble, and the discharge pipe 13 can be directly disassembled and replaced when there is a lot of scale on the inner wall of the discharge pipe 13. After the cleaning liquid enters the autoclave 10, it can mainly clean the scale on the surface of the stirring paddle 111. Accordingly, the end of the steam pipeline 20 extending into the autoclave 10 can be close to the stirring paddle 111, and in particular, the end of the steam pipeline 20 can be arranged above the stirring paddle 111 and relatively close to the stirring paddle 111, so that the cleaning liquid can clean the surface of the stirring paddle 111.

[0048] The high-pressure acid leaching equipment may also include a descaling control module, which can monitor the working current of the stirring device 11 (especially the stirring paddle 111). When the working current of the stirring device 11 is too large (exceeding a certain range), it indicates that the scaling on the surface of the stirring paddle 111 may have affected its normal operation. Based on the magnitude of the working current of the stirring device 11, the descaling control module can control the descaling liquid inlet bypass 30 to pass the descaling liquid into the interior of the autoclave 10. When the working current of the stirring device 11 returns to the normal range, it indicates that the scaling on the surface of the stirring paddle 111 has been effectively cleaned, and the descaling liquid can be stopped from being passed into the interior of the autoclave 10 and the normal high-pressure acid leaching production operation can be resumed.

[0049] Furthermore, the autoclave 10 may further include one or more partitions 12, which may separate the interior of the autoclave 10 into a plurality of stirring zones to improve the production efficiency of the high-pressure acid leaching operation. The liquid level of the slurry in the plurality of stirring zones may gradually decrease from the feed end to the discharge end of the autoclave 10. Figure 1 and Figure 2In the figure, the left end of the autoclave 10 is the feed end, and the right end of the autoclave 10 is the discharge end. The liquid level of the slurry in the autoclave 10 can gradually decrease from the left end to the right end of the autoclave 10. The steam pipeline 20 can form a plurality of branches 21, and the plurality of branches 21 can be respectively connected to different stirring areas. The plurality of branches 21 can respectively pass descaling liquid into the autoclave 10 to clean the scale in at least part of the stirring area. Preferably, the number of branches 21 can be the same as the number of stirring areas, and each branch 21 can be respectively connected to a different stirring area. At least one stirring device 11 can be arranged in each stirring area. Exemplarily, in Figure 1 and Figure 2 In the embodiment, a total of 4 partitions 12 are provided in the autoclave 10, which divide a total of 5 stirring areas in the autoclave 10. A total of 5 stirring devices 11 are provided in the autoclave 10, and one stirring device 11 is provided in each stirring area. By cleaning the interior of the autoclave 10 through multiple branches 21, the descaling effect and descaling efficiency can be improved.

[0050] The descaling liquid inlet bypass 30 may be provided with a switch valve for controlling the on and off of the descaling liquid inlet bypass 30; and / or the steam pipeline 20 (especially the intersection of the steam pipeline 20 and the descaling liquid inlet bypass 30) may be provided with a switching valve for controlling the communication between the descaling liquid inlet bypass 30 and the steam pipeline 20. The descaling liquid inlet bypass 30 and / or the steam pipeline 20 may also be provided with a flow meter to monitor the inlet amount of the descaling liquid.

[0051] The autoclave 10 may also be provided with an exhaust valve for reducing temperature and pressure. The exhaust valve may be used to reduce the temperature and pressure in the autoclave 10 before the descaling operation is performed.

[0052] like Figure 1As shown, the high-pressure acid leaching equipment may also include a flash device 40, a sulfuric acid pipeline 50, a slag outlet 60 and a preheating device 70. The flash device 40 is connected to the autoclave 10 via a discharge pipe 13, and the slurry in the autoclave 10 can enter the flash device 40 for flash evaporation. The flash device 40 may be a multi-stage flash device. The flash device 40 may be provided with a downstream outlet 41 to pass the flashed material into the downstream process equipment. The sulfuric acid pipeline 50 may be connected to the autoclave 10, and is used to pass sulfuric acid into the autoclave 10 for high-pressure acid leaching. The slag outlet 60 may be connected to the autoclave 10 and / or the flash device 40, and is used to discharge the generated slag. The slag outlet 60 may be connected to the bottom of the autoclave 10 and / or the flash device 40. The preheating device 70 may be provided with a slurry inlet 71 and connected to the autoclave 10, so as to pass the slurry into the autoclave 10 after it is preheated, and then pass the preheated slurry into the autoclave 10. The preheating device 70 may be a multi-stage preheating device. The preheating device 70 may also be connected to the flash evaporation device 40 to preheat the slurry using flash gas. The preheating device 70 may also be provided with a waste gas outlet to discharge waste gas during the preheating process, especially acid-containing waste gas.

[0053] The embodiments of the present application also provide a working method of a high-pressure acid leaching device with a descaling function, which can be applied to the aforementioned high-pressure acid leaching device.

[0054] Before the descaling liquid is introduced into the autoclave 10 through the descaling liquid inlet bypass 30, the feeding, discharging and high-pressure steam introduction process of the high-pressure acid leaching equipment can be stopped (the process of introducing sulfuric acid into the autoclave 10 through the sulfuric acid pipeline 50 can also be closed), that is, the feeding valve, the discharging valve and the steam feeding valve can be closed (the sulfuric acid feeding valve can also be closed). In addition, the exhaust valve can be opened to reduce the temperature and pressure in the autoclave 10. Before the descaling liquid is introduced into the autoclave 10, the temperature of the autoclave 10 can be reduced to 170 to 200 degrees Celsius. If the temperature is too high (higher than 200 degrees Celsius), the descaling liquid may easily corrode the steam pipeline 20 and other devices in the autoclave 10; if the temperature is too low (lower than 170 degrees Celsius), the internal slurry of the autoclave 10 may be more likely to crystallize and produce scaling.

[0055] The components of the descaling liquid 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 descaling liquid is not easy to corrode the steam pipeline 20 in an environment of 170-200 degrees Celsius. In addition, the above-mentioned descaling liquid has a faster dissolution rate for scale in an environment of 170-200 degrees Celsius, which can minimize the impact of the descaling operation on the normal high-pressure acid leaching production process. If the descaling environment temperature of the descaling liquid is too high (higher than 200 degrees Celsius), the trend of the hydrolysis reaction (here, the hydrolysis reaction is the reverse reaction of the acidolysis reaction of sulfuric acid and scaling substances such as ferric oxide) may be increased, thereby inhibiting the decomposition rate of the scale. If the descaling environment temperature of the descaling liquid is too low (lower than 170 degrees Celsius), the dissolution rate of the scale will be reduced due to the temperature reduction. In summary, considering the corrosion of the cleaning liquid to the steam pipeline 20 and the dissolution rate of the scale, it is more appropriate to keep the internal temperature of the autoclave 10 within the range of 170 to 200 degrees Celsius during the cleaning operation (before starting the cleaning operation). More preferably, the temperature of the autoclave 10 can be kept at 200 degrees Celsius.

[0056] Here are some comparisons of different cleaning liquids:

[0057] Comparative Example 1

[0058] The descaling liquid provided in the present application has a composition of sulfuric acid with a percentage concentration of 10% to 20% and iron sulfate with a mass concentration of 0.5 to 1 gram per liter. The corrosion rate of the descaling liquid on the steam pipeline sample in an environment of 200 degrees Celsius is 0.01 to 0.02 mm / a (millimeter per year).

[0059] Comparative Example 2

[0060] The composition is sulfuric acid with a percentage concentration of 10% to 20%. The corrosion rate of the steam pipeline sample in an environment of 200 degrees Celsius is 90 to 120 mm / a (millimeter per year).

[0061] Comparative Example 3

[0062] 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.

[0063] In summary, the components of the descaling liquid provided in the embodiments of the present application are less corrosive to the steam pipeline at a temperature of 200 degrees and are suitable for transportation through the steam pipeline 20.

[0064] The descaling control module can determine whether descaling is required based on the magnitude of the working current of the stirring device monitored by it, and can provide feedback of its monitoring and judgment results to the operator. The descaling control module can automatically or according to the operator's instructions control the high-pressure acid leaching equipment to perform descaling operations.

[0065] Furthermore, when the descaling control module monitors that the current of the stirring device returns to the normal current range, that is, the scale on the stirring paddle 111 has been cleaned to the point where it does not affect the normal operation of the stirring paddle 111, the descaling liquid can be stopped from being introduced into the autoclave 10, and / or the descaling control module can feedback relevant information to the operator to terminate the descaling operation in a timely manner.

[0066] The following briefly describes some of the beneficial effects of the above-mentioned embodiments of the present application.

[0067] The high-pressure acid leaching equipment with a descaling function and its working method provided by the embodiment of the present application use a steam pipeline to introduce a descaling liquid into the pressure autoclave, and use the descaling liquid to clean at least part of the scale in the pressure autoclave, especially reducing the scale wrapped on the surface of the stirring paddle in the pressure autoclave, thereby reducing the adverse effects of scaling on the operation of the high-pressure acid leaching equipment. The descaling scheme provided by the present application utilizes the existing structure of the steam pipeline of the high-pressure acid leaching equipment, which can reduce the production and operation costs and working difficulty of the equipment. At the same time, the present application also provides the descaling liquid composition suitable for the high-pressure acid leaching equipment and its suitable ambient temperature range. The use of the descaling liquid within the suitable temperature range can effectively reduce the corrosion of the acidic descaling liquid to the steam pipeline and maintain a faster scale dissolution rate. This embodiment can control the descaling operation of the high-pressure acid leaching equipment in an automatic or manual control manner through a descaling control module to meet the flexible control requirements in actual production.

[0068] It is understood that in the present application, when the number of parts or components is not particularly limited, the number may be one or more, and the multiple here means two or more. For the case where the number of parts or components shown in the drawings and / or described in the specification is a specific number such as two, three, four, etc., the specific number is usually exemplary and not restrictive, and it can be understood as multiple, that is, two or more, but this does not mean that the present application excludes the case of one.

[0069] It should be understood that the above embodiments are merely exemplary and are not intended to limit the present application. Those skilled in the art may make various modifications and changes to the above embodiments under the guidance of the present application without departing from the scope of the present application.

Claims

1. A high pressure acid leaching equipment with descaling function, characterized in that: The invention comprises a pressure vessel (10), a steam pipeline (20) and a descaling liquid inlet bypass (30), wherein the steam pipeline (20) is connected to the pressure vessel (10) and is used to pass 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 pass the descaling liquid into the interior of the autoclave (10) via at least a portion of the steam pipeline (20) to clean at least a portion of the scale inside the autoclave (10).

2. The high-pressure acid leaching equipment with descaling function according to claim 1 is characterized in that: The descaling liquid comprises sulfuric acid with a percentage concentration of 10% to 20% and iron sulfate with a mass concentration of 0.5 to 1 g / L.

3. The high-pressure acid leaching equipment with descaling function according to claim 1 is characterized in that: The autoclave (10) comprises one or more stirring devices (11), wherein the stirring device (11) comprises a stirring paddle (111) arranged inside the autoclave (10). The descaling liquid introduced into the interior of the autoclave (10) through the descaling liquid inlet bypass (30) is capable of cleaning at least part of the scale on at least one of the stirring blades (111).

4. The high-pressure acid leaching equipment with descaling function according to claim 3 is characterized in that: It also includes a descaling control module, which is capable of monitoring the working current of the stirring device (11) to control the descaling liquid inlet bypass (30) to pass the descaling liquid into the interior of the autoclave (10) based on the magnitude of the working current.

5. The high pressure acid leaching equipment with descaling function according to any one of claims 1 to 4, characterized in that: The autoclave (10) further comprises one or more partitions (12), wherein the partitions (12) divide the interior of the autoclave (10) into a plurality of stirring zones. The steam pipeline (20) forms a plurality of branches (21), and the plurality of branches (21) are respectively connected to different stirring areas to clean scale in at least part of the stirring areas.

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

7. The high pressure acid leaching equipment with descaling function according to claim 1, characterized in that: The descaling liquid inlet bypass (30) is provided with a switch valve for controlling the on-off of the descaling liquid inlet bypass (30); and / or The steam pipeline (20) is provided with a switching valve for controlling the communication between the descaling liquid inlet bypass (30) and the steam pipeline (20).

8. A working method of a high pressure acid leaching equipment with a descaling function, characterized in that: The high-pressure acid leaching equipment with a descaling function is the high-pressure acid leaching equipment with a descaling function as claimed in any one of claims 1 to 7, Before the descaling liquid inlet bypass (30) is passed into the interior of the autoclave (10), the high-pressure acid leaching equipment with descaling function stops feeding, discharging, and passing 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 descaling liquid comprises sulfuric acid with a percentage concentration of 10% to 20% and iron sulfate with a mass concentration of 0.5 to 1 g / L.

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 inlet bypass (30) is passed into the interior of the autoclave (10), the temperature inside the autoclave (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 a descaling function is the high-pressure acid leaching equipment with a descaling function as claimed in claim 4, The descaling control module determines whether descaling is required based on the magnitude of the working 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 interior of the autoclave (10) according to instructions from an operator.

12. The working method of the high pressure acid leaching equipment with descaling function according to claim 11, characterized in that: After the descaling control module detects that the working current of the stirring device (11) has returned to a normal range, the descaling liquid is stopped from being introduced into the interior of the autoclave (10).

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