High-pressure acid leaching system

Abstract

The invention provides a high-pressure acid leaching system. The high-pressure acid leaching system comprises an autoclave, a preheater, a flash tank and an autoclave feed pump, wherein the autoclave is connected to the flash tank, the flash tank is connected to the preheater so as to introduce flash gas into the preheater, and the preheater is connected to the autoclave through the autoclave feeding pump. And high-pressure air is introduced into the autoclave and / or the flash tank. The high-pressure air is introduced into the autoclave and / or the flash tank, so that the flash gas and the high-pressure air can enter the preheater together, the internal pressure of the preheater is increased, the temperature of ore pulp at an outlet of the preheater is reduced, and the cavitation phenomenon is avoided or reduced.

Description

Technical Field

[0001] The present application relates to the technical field of high-pressure acid leaching, and in particular to a high-pressure acid leaching system. Background Art

[0002] In recent years, the demand for nickel in industrial production has been increasing day by day. The high-pressure acid leaching process of laterite nickel ore has been the mainstream process for extracting nickel from minerals in recent years. In the current operation method, since the slurry in the preheater, flash tank and autoclave is operating at a state close to the saturated steam pressure, the pumps and valves in the system are operating under relatively harsh conditions, which is prone to cavitation and other phenomena that affect their service life and increase the maintenance cost of the system.

[0003] CN117083397A discloses a system and method for controlling the amount of Al precipitation in a high-pressure acid leaching process of laterite nickel ore. The system includes an autoclave and a post-processing device. The autoclave includes an autoclave body, a first addition pipe, a second addition pipe, and a discharge pipe. The post-processing device is connected to the discharge pipe, and the post-processing device includes a flash evaporation mechanism and a leachate storage tank. The flash evaporation mechanism is connected to the discharge pipe, and the leachate storage tank is connected to the flash evaporation mechanism. Further, the flash evaporation mechanism includes a primary flash evaporator, a secondary flash evaporator, and a tertiary flash evaporator. The primary flash evaporator, the secondary flash evaporator, and the tertiary flash evaporator are connected in sequence, and the primary flash evaporator is connected to the discharge pipe.

[0004] The Al precipitation amount control system for high-pressure acid leaching process of laterite nickel ore disclosed in the above invention application discloses a high-pressure autoclave and a multi-stage flash evaporation mechanism connected thereto, but does not disclose a structure for recycling the flash gas generated by the multi-stage flash evaporation mechanism and related improvement schemes. Summary of the invention

[0005] 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 system, which can pass at least part of the flash gas generated by the first-stage flash tank into the final-stage preheater to heat the slurry, and can also pass high-pressure air into the autoclave and / or the flash tank to reduce the occurrence of cavitation and increase the service life of the autoclave feed pump.

[0006] The present application provides a high-pressure acid leaching system, which includes a pressure kettle, a preheater, a flash tank and a pressure kettle feed pump, wherein:

[0007] The autoclave is connected to the flash tank, the flash tank is connected to the preheater to pass the flash gas into the preheater, and the preheater is connected to the autoclave via the autoclave feed pump.

[0008] High-pressure air is introduced into the autoclave and / or the flash tank.

[0009] In at least one possible embodiment, the high-pressure acid leaching system includes a first flow control mechanism for adjusting the flow rate of the high-pressure air entering the autoclave.

[0010] The first flow control mechanism is configured to control the flow rate of the high-pressure air according to the difference between the internal pressure of the autoclave and the valve front pressure of the flash tank.

[0011] In at least one possible implementation, the first flow control mechanism is configured as:

[0012] A plurality of continuous different difference relationships all correspond to the same flow rate, and the flow rate corresponds to a maximum value among a plurality of continuous different difference relationships;

[0013] Alternatively, each different difference relationship corresponds to a different flow rate.

[0014] In at least one possible embodiment, the autoclave comprises a first exhaust valve.

[0015] The first flow control mechanism calculates the theoretical pressure in the autoclave according to the internal pressure of the autoclave and the pressure before the valve of the flash tank.

[0016] The opening of the first exhaust valve and / or the flow rate of the high-pressure air introduced into the pressure reactor are controlled according to the numerical relationship between the theoretical pressure in the reactor and the measured actual pressure in the reactor.

[0017] In at least one possible embodiment, the theoretical autoclave internal pressure is obtained according to the sum of the difference between the internal pressure of the autoclave and the pressure before the valve of the flash tank and the saturated steam pressure corresponding to the temperature of the autoclave.

[0018] In at least one possible implementation, the numerical relationship includes a difference relationship and / or a ratio relationship.

[0019] In at least one possible embodiment, a second flow control mechanism is included to adjust the flow rate of high-pressure air entering the flash tank.

[0020] The second flow control mechanism is configured to control the flow rate of the high-pressure air entering the flash tank within a preset range.

[0021] In at least one possible embodiment, the flash tank includes a second exhaust valve, and the theoretical tank pressure is calculated according to the preset range.

[0022] The second flow control mechanism controls the opening of the second exhaust valve and / or controls the flow of the high-pressure air entering the flash tank according to the numerical relationship between the theoretical tank pressure and the measured actual tank pressure.

[0023] In at least one possible implementation, the theoretical tank internal pressure is obtained according to the sum of the saturated vapor pressure corresponding to the temperature of the flash tank and the pressure corresponding to the preset range.

[0024] In at least one possible embodiment, a gas regulating system is included, and the gas regulating system is configured to adjust the amount of gas of the flash gas in the flash tank entering the preheater according to the temperature of the preheater.

[0025] In at least one possible embodiment, the preheater includes at least a primary preheater, a secondary preheater and a final preheater whose temperatures are successively increased, and the flash tank includes at least a primary flash tank, a secondary flash tank and a tertiary flash tank whose pressures are successively decreased.

[0026] The secondary flash tank is connected to the secondary preheater, the tertiary flash tank is connected to the primary preheater, and the primary flash tank is connected to the final preheater.

[0027] The high-pressure acid leaching system provided by the present application can pass high-pressure air into the pressure autoclave and / or flash tank respectively, so that the flash gas and high-pressure air enter the preheater together, so as to increase the pressure in the preheater (especially the final preheater) and reduce the slurry temperature at the outlet of the preheater. In addition, the occurrence of cavitation can be avoided or reduced, the service life of the pressure autoclave feed pump can be extended, the equipment can be operated stably for a long time, and the operation and maintenance costs of the high-pressure acid leaching system can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure is a simplified structural diagram of a high-pressure acid leaching system according to one embodiment of the present application.

[0029] Description of Reference Numerals

[0030] 10. Autoclave

[0031] 21. Primary preheater

[0032] 22 Secondary preheater

[0033] 23 Three-stage preheater

[0034] 31. Primary Flash Tank

[0035] 32 Secondary Flash Tank

[0036] 33 Three-stage flash tank

[0037] 41 Primary feed pump

[0038] 42 Secondary feed pump

[0039] 43 Three-stage feed pump

[0040] 44 Autoclave feed pump DETAILED DESCRIPTION

[0041] 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.

[0042] The embodiment of the present application provides a high-pressure acid leaching system, which may include a pressure autoclave 10, a final stage preheater, a primary flash tank, and a pressure autoclave feed pump 44. Preferably, the high-pressure acid leaching system may include a multi-stage preheater, a multi-stage flash tank, and a multi-stage feed pump to achieve step-by-step heating and flashing of the slurry, thereby improving the efficiency and benefits of slurry processing. The high-pressure acid leaching system provided in this embodiment can be applied to the high-pressure acid leaching production process of laterite nickel ore. It can be understood that the application scenarios of the high-pressure acid leaching system are not limited thereto. The connection referred to in this application includes direct connection and indirect connection via structures such as pipes and valves.

[0043] Specifically, the multi-stage preheater may include a final preheater connected to the autoclave 10 via a pump, a valve, etc. Exemplarily, the multi-stage preheater may be a three-stage preheater, namely, a primary preheater 21, a secondary preheater 22, and a tertiary preheater 23 (it can be understood that the tertiary preheater is the final preheater in this example), and the operating temperature of the multi-stage preheater may be increased in sequence. The multi-stage flash tank may include a three-stage flash tank, namely, a primary flash tank 31, a secondary flash tank 32, and a tertiary flash tank 33. The steam pressure of the primary flash tank 31, the secondary flash tank 32, and the tertiary flash tank 33 may be reduced in sequence, that is, the primary flash tank 31 may be a high-pressure flash tank, the secondary flash tank 32 may be a medium-pressure flash tank, and the tertiary flash tank 33 may be a low-pressure flash tank (flash: high-pressure saturated water enters a relatively low-pressure container, and the saturated water becomes saturated water vapor and saturated water under a portion of the container pressure due to the sudden decrease in pressure). The multi-stage feed pump may include a three-stage feed pump, namely, a primary feed pump 41, a secondary feed pump 42, a tertiary feed pump 43 and a pressure autoclave feed pump 44. The primary feed pump 41, the secondary feed pump 42, the tertiary feed pump 43 and the pressure autoclave feed pump 44 may be disposed upstream of the primary preheater 21, the secondary preheater 22, the tertiary preheater 23 and the pressure autoclave 10, respectively.

[0044] It can be understood that the high-pressure acid leaching system may also include a pipeline system, a valve system, a control and regulation system, etc.

[0045] The primary preheater 21, the secondary preheater 22 and the tertiary preheater 23 can be connected in sequence (indirectly connected via a pump and a pipeline), and the material (ore pulp) can enter the primary preheater 21, and enter the autoclave 10 after passing through the primary preheater 21, the secondary preheater 22 and the tertiary preheater 23 in sequence. The autoclave 10 can be connected to the primary flash tank 31, and the material (ore pulp) treated in the autoclave 10 can be discharged into the primary flash tank 31 through the discharge pipe, and enter the downstream production equipment after passing through the primary flash tank 31, the secondary flash tank 32 and the tertiary flash tank 33 in sequence. The primary flash tank 31 is the flash tank into which the ore pulp is first introduced, and the temperature of the ore pulp is gradually reduced. The temperature of the flash gas generated in the primary flash tank is higher than the temperature of the flash gas generated in the flash tank (secondary flash tank, tertiary flash tank) connected subsequently. A pressure reducing valve can be provided upstream of each flash tank to relatively reduce the pressure in the flash tank.

[0046] The gases generated in the multi-stage flash tank can be respectively introduced into the multi-stage preheater to heat the material step by step using the flash gas (saturated steam). In order to achieve a step-by-step increase in the material temperature, the preheating temperature of the multi-stage preheater also needs to be increased step by step, that is, the temperature of the final preheater (third-stage preheater) is higher than the preheating temperature of the preheater connected in front (first-stage preheater, second-stage preheater). Furthermore, the final preheater can be connected to the first-stage flash tank, and the primary preheater can be connected to the final flash tank, so that the temperature of the multi-stage flash tank matches that of the multi-stage preheater. Specifically, if Figure 1 As shown, the slurry (exemplarily, it can be formed by adding water and other auxiliary materials to the laterite nickel ore raw material) can be transported to the primary preheater 21 via the primary feed pump 41, and the steam in the tertiary flash tank 33 can be transported to the primary preheater 21. The steam from the tertiary flash tank 33 can heat the slurry in the primary preheater 21, and exemplarily, the slurry can be heated from room temperature to 95 to 100 degrees. The slurry in the primary preheater 21 can be transported to the secondary preheater 22 via the secondary feed pump 42, and the steam in the secondary flash tank 32 can be transported to the secondary preheater 22. The steam from the secondary flash tank 32 can further heat the slurry in the secondary preheater 22, and exemplarily, the slurry can be heated to 150 to 155 degrees. The slurry in the secondary preheater 22 can be transported to the tertiary preheater 23 via the tertiary feed pump 43, and the steam in the primary flash tank 31 can be transported to the tertiary preheater 23. The steam from the primary flash tank 31 can further heat the pulp in the tertiary preheater 23. For example, the pulp can be heated to 200 to 205 degrees. It can be understood that the connection structure and working process of the multi-stage flash tank, multi-stage feed pump and multi-stage preheater can better meet the heating requirements of the pulp and the effective recovery and utilization of heat energy in the high-pressure acid leaching process.

[0047] The slurry heated by the tertiary preheater 23 can be pumped into the autoclave 10 via the autoclave feed pump 44. Concentrated sulfuric acid and steam (high-pressure steam) can be added to the autoclave 10 in a certain ratio (for example, a suitable acid-ore ratio, i.e., the mass ratio of the dry weight of the slurry to the acid), and the temperature of the slurry is raised to 245 to 255 degrees by the heat generated when the concentrated sulfuric acid and steam are diluted. In a test example, the leaching rate of nickel in the slurry in the autoclave is greater than 95%, the leaching rate of cobalt is greater than 92%, and most of the impurities such as iron, silicon and aluminum remain in the slag.

[0048] It can be understood that the primary preheater 21, the secondary preheater 22, the tertiary preheater 23, the autoclave 10 and the primary flash tank 31 are all provided with an exhaust gas discharge structure (eg, an exhaust gas discharge pipe) to discharge the exhaust gas generated during the production process.

[0049] Preferably, the primary feed pump 41 , the secondary feed pump 42 and the tertiary feed pump 43 may be centrifugal pumps.

[0050] Preferably, the pressure kettle feed pump 44 can be a diaphragm pump, especially a one-way valve diaphragm pump. It can be understood that the diaphragm pump has a simple structure, low cost, good corrosion resistance, and is suitable for use in the slurry transportation process.

[0051] The high-pressure acid leaching system of this embodiment can introduce high-pressure air into the autoclave 10. It can be understood that introducing high-pressure air into the autoclave 10 can increase the pressure in the autoclave 10, and can avoid or reduce the flashing phenomenon of the slurry in the autoclave and the discharge pipe in advance (before entering the flash tank).

[0052] The high-pressure acid leaching system of this embodiment can also introduce high-pressure air into the multi-stage flash tank, especially into the primary flash tank 31. It can be understood that when only the flash gas generated by the primary flash tank 31 is introduced into the final preheater (third-stage preheater), the slurry in the final preheater is close to or in a saturated vapor pressure state. The introduction of high-pressure air into the primary flash tank 31 can make the gas transported to the third-stage preheater 23 include flash gas and high-pressure air (normal temperature high-pressure air), which can increase the pressure in the third-stage preheater 23 to a certain extent and reduce the heat exchange efficiency between the primary flash tank 31 and the third-stage preheater 23 (that is, reduce the effect of flash gas on raising the slurry temperature to a certain extent). The above-mentioned technical solution of introducing high-pressure air into the first-stage flash tank 31 can further make the slurry temperature at the outlet of the third-stage preheater lower than its saturation temperature (under the working pressure of the third-stage preheater), so that when the slurry enters the pressure autoclave through the pressure autoclave feed pump 44, the pressure autoclave feed pump (especially when it is a diaphragm pump) is not easy to (avoid or reduce) cavitation, etc., so as to reduce the loss of the pressure autoclave feed pump and increase the service life of the pressure autoclave feed pump. The solution of introducing high-pressure air into the first-stage flash tank 31 can greatly improve the working environment of the pressure autoclave feed pump 44 and valves in the high-pressure acid leaching system, increase the service life of the pressure autoclave feed pump and valves, reduce the maintenance and replacement frequency of the equipment, and improve the economic benefits. It can be understood that since the pressure autoclave is connected to the first-stage flash tank, only high-pressure air is introduced into the pressure autoclave 10, and the high-pressure air can also be indirectly introduced into the first-stage flash tank, which can also have the above-mentioned technical effects.

[0053] During the operation of the high-pressure acid leaching system, high-pressure air can be continuously introduced into the pressure reactor and / or the flash tank, and the high-pressure air content and pressure in the high-pressure acid leaching system are maintained relatively stable.

[0054] Preferably, the pressure in the autoclave after the high-pressure air is introduced can be 5 to 5.5 MPa (megapascals). The pressure of the high-pressure air introduced into the autoclave can be greater than the pressure in the autoclave of the autoclave 10, so that the high-pressure air can be smoothly introduced into the autoclave 10. The pressure in the flash tank after the high-pressure air is introduced can be 2 to 2.2 MPa. The pressure of the high-pressure air introduced into the flash tank (primary flash tank) can be greater than the pressure in the tank of the flash tank, so that the high-pressure air can be smoothly introduced into the flash tank. The temperature of the high-pressure air introduced into the autoclave and the flash tank can be room temperature. It can be understood that under this pressure and temperature condition, the beneficial effect of introducing high-pressure air into the high-pressure acid leaching system can be better achieved.

[0055] It can be understood that the functions and effects of the high-pressure air introduced in this embodiment and the steam (high-pressure steam) introduced into the autoclave are different. The high-pressure air and steam can be introduced into the autoclave simultaneously or separately.

[0056] The control and regulation system of the high-pressure acid leaching system of this embodiment may include a gas control system, and the gas control system may include a valve, and may also include a temperature sensor and a pressure sensor. The valve can adjust the pressure, flow rate, etc. of the high-pressure air. The temperature sensor and the pressure sensor can monitor the temperature and pressure, etc. during the transportation of the high-pressure air. The gas control system can control the amount of flash gas generated by the multi-stage flash tank and / or the high-pressure air introduced into the multi-stage preheater. The flash gas generated by the multi-stage flash tank can be partially or completely (i.e., at least partially) introduced into the multi-stage preheater, and the gas control system can control the amount of flash gas introduced into the multi-stage preheater according to the actual production needs. It can be understood that the gas control system can avoid the amount of flash gas introduced into the multi-stage preheater (the heat carried by the flash gas) far greater than the amount of flash gas (heat) required by the multi-stage preheater, thereby avoiding the slurry at the outlet of the three-stage preheater from being close to the saturated state (saturated vapor pressure state).

[0057] The gas control system may be configured to adjust the amount of flash gas entering the preheater from the flash tank (including one or more flash tanks) according to the temperature of the preheater (including one or more preheaters), thereby achieving dynamic control of the temperature in the preheater. In particular, the gas control system may be configured to adjust the amount of gas entering the preheater from the flash tank connected to the preheater according to the temperature of each preheater.

[0058] The high-pressure acid leaching system may also include a first flow control mechanism, which can be used to adjust the flow rate of high-pressure air entering the autoclave 10. Further, the first flow control mechanism can be configured to control the flow rate of high-pressure air according to the difference between the internal pressure of the autoclave 10 and the valve pressure before the flash tank (primary flash tank). Here, the valve pressure refers to the pressure value measured at the valve arranged upstream of the flash tank. Specifically, the valve pressure before the flash tank is the pressure after the internal pressure of the autoclave is subtracted from the pipeline loss pressure, that is, the difference between the internal pressure of the autoclave 10 and the valve pressure before the flash tank (primary flash tank) is the pipeline loss pressure. The difference relationship can include the relative size relationship of the numerical value, the difference numerical value relationship, the multiple relationship, etc. In other words, the flow rate of high-pressure air can be controlled according to the relative size, difference interval, multiple interval, etc. of the difference between the internal pressure of the autoclave 10 and the valve pressure before the flash tank (primary flash tank).

[0059] The first flow control mechanism can be further configured so that a plurality of continuous different difference relationships all correspond to the same flow rate, and the flow rate corresponds to the maximum value of a plurality of continuous different difference relationships. That is, when the difference relationship is within a certain range, the flow rate of the high-pressure air is the same. Alternatively, each different difference relationship corresponds to a different flow rate. That is, the first flow control mechanism can flexibly control the flow rate of the high-pressure air in a variety of ways.

[0060] The autoclave may further include a first exhaust valve, which can calculate the theoretical pressure in the autoclave according to the internal pressure of the autoclave 10 and the pressure before the valve of the flash tank. Then, the opening of the first exhaust valve and / or the flow rate of high-pressure air entering the autoclave 10 are controlled according to the numerical relationship between the theoretical pressure in the autoclave and the measured (for example, measured using a pressure gauge) actual pressure in the autoclave. In this way, secondary control of the high-pressure air flow rate can be achieved, further improving the control accuracy of the pressure in the autoclave. Here, the numerical relationship can include a difference relationship, a ratio relationship, etc.

[0061] The specific calculation method of the theoretical pressure in the autoclave can be the difference between the internal pressure of the autoclave 10 and the pressure before the flash tank valve plus the sum of the saturated steam pressure corresponding to the temperature of the autoclave 10. For example, according to actual experience, the theoretical pressure in the autoclave P = P autoclave saturation + 0.6Mpa.

[0062] The high-pressure acid leaching system may further include a second flow control mechanism, which may be used to control the flow rate of the high-pressure air entering the flash tank. The second flow control mechanism may be configured to control the flow rate of the high-pressure air entering the flash tank within a preset range to maintain a stable flow rate of the high-pressure air entering the flash tank.

[0063] The flash tank (particularly the first-stage flash tank) may include a second exhaust valve. The second flow control mechanism may control the opening of the second exhaust valve and / or control the flow rate of high-pressure air entering the flash tank according to the numerical relationship between the theoretical tank pressure and the actual tank pressure measured (e.g., measured using a pressure gauge). The theoretical tank pressure may be obtained by summing the saturated vapor pressure corresponding to the temperature of the flash tank (first-stage flash tank) and the high-pressure air flow rate within a preset range. Exemplarily, based on actual experience, the theoretical tank pressure P = P tank saturation + 0.1 to 0.2 MPa.

[0064] The first flow control mechanism and the second flow control mechanism may include a valve, a pressure gauge, a flow meter, a control unit, etc. Further, the gas control mechanism and the second flow control mechanism may share some structures, in particular, may share some structures in the flash tank (primary flash tank). Exemplarily, the gas control mechanism and the second flow control mechanism may share the pressure gauge in the flash tank.

[0065] The embodiment of the present application also provides a working method of a high-pressure acid leaching system, which can be implemented using the above-mentioned high-pressure acid leaching system. The working method of the high-pressure acid leaching system can mainly include passing the flash gas generated in the flash tank into the preheater for preheating the ore. Add the slurry after preheating to the autoclave. Pass the slurry in the autoclave into the flash tank (primary flash tank) for flash evaporation. And pass high-pressure air into the autoclave and the flash tank (primary flash tank) respectively. Some specific contents and technical effects of the working method have been described in detail in the introduction of the above-mentioned high-pressure acid leaching system, and will not be repeated here.

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

[0067] The present application proposes a high-pressure acid leaching system, which can pass at least part of the flash gas generated by the multi-stage flash tank into the preheater to preheat the slurry, and can control the reasonable amount of flash gas introduced through the gas regulating system. The application can also pass high-pressure air into the pressure kettle and the flash tank respectively, which can reduce the occurrence of cavitation, extend the service life of the pressure kettle feed pump and valve, enable the equipment to operate stably for a long time, and reduce the operation and maintenance costs of the high-pressure acid leaching system.

[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 system, characterized in that: The invention comprises a pressure vessel (10), a preheater, a flash tank and a pressure vessel feed pump (44), wherein: The autoclave (10) is connected to the flash tank, the flash tank is connected to the preheater to pass the flash gas into the preheater, and the preheater is connected to the autoclave (10) via the autoclave feed pump (44). High-pressure air is introduced into the autoclave and / or the flash tank.

2. The high pressure acid leaching system according to claim 1, characterized in that: comprising a first flow control mechanism for adjusting the flow rate of the high-pressure air entering the autoclave, The first flow control mechanism is configured to control the flow rate of the high-pressure air according to the difference between the internal pressure of the autoclave (10) and the pressure before the valve of the flash tank.

3. The high pressure acid leaching system according to claim 2, characterized in that: The first flow control mechanism is configured as: A plurality of continuous different difference relationships all correspond to the same flow rate, and the flow rate corresponds to a maximum value among a plurality of continuous different difference relationships; Alternatively, each different difference relationship corresponds to a different flow rate.

4. The high pressure acid leaching system according to claim 3, characterized in that: The autoclave (10) comprises a first exhaust valve, The first flow control mechanism calculates the theoretical pressure in the autoclave according to the internal pressure of the autoclave (10) and the pressure before the valve of the flash tank. The opening of the first exhaust valve and / or the flow rate of the high-pressure air introduced into the pressure reactor (10) are controlled according to the numerical relationship between the theoretical pressure in the reactor and the measured actual pressure in the reactor.

5. The high pressure acid leaching system according to claim 4, characterized in that: The theoretical pressure inside the autoclave is obtained based on the sum of the difference between the internal pressure of the autoclave (10) and the pressure before the valve of the flash tank and the saturated steam pressure corresponding to the temperature of the autoclave (10).

6. The high pressure acid leaching system according to claim 4, characterized in that: The numerical relationship includes a difference relationship and / or a ratio relationship.

7. The high pressure acid leaching system according to claim 1, characterized in that: A second flow control mechanism is included for adjusting the flow of high-pressure air entering the flash tank, The second flow control mechanism is configured to control the flow rate of the high-pressure air entering the flash tank within a preset range.

8. The high pressure acid leaching system according to claim 7, characterized in that: The flash tank includes a second exhaust valve, and the theoretical tank pressure is calculated according to the preset range. The second flow control mechanism controls the opening of the second exhaust valve and / or controls the flow of the high-pressure air entering the flash tank according to the numerical relationship between the theoretical tank pressure and the measured actual tank pressure.

9. The high pressure acid leaching system according to claim 8, characterized in that: The theoretical tank internal pressure is obtained according to the sum of the saturated vapor pressure corresponding to the temperature of the flash tank and the pressure corresponding to the preset range.

10. The high pressure acid leaching system according to claim 1, characterized in that: A gas regulating system is included, and the gas regulating system is configured to adjust the amount of gas entering the preheater from the flash gas in the flash tank according to the temperature of the preheater.

11. The high pressure acid leaching system according to claim 1, characterized in that: The preheater comprises at least a primary preheater (21), a secondary preheater (22) and a final preheater, the temperatures of which are successively increased, and the flash tank comprises at least a primary flash tank (31), a secondary flash tank (32) and a tertiary flash tank (33), the pressures of which are successively decreased. The secondary flash tank (32) is connected to the secondary preheater (22), the tertiary flash tank (33) is connected to the primary preheater (21), and the primary flash tank is connected to the final preheater.

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