Nickel laterite ore high-pressure leaching residence time optimization system

Abstract

Disclosed in the present invention is a nickel laterite ore high-pressure leaching residence time optimization system, comprising a data acquisition module, an actual residence time calculation module, an optimal residence time determination module and a residence time control module. The actual residence time calculation module is used for obtaining the actual residence time of an ore pulp in a high-pressure kettle during a high-pressure acid leaching process. The optimal residence time determination module is used for obtaining the optimal residence time corresponding to the maximum revenue value. The beneficial effects of the present invention are: inputting operational conditions such as real-time ore composition, an acid leaching temperature, and an acid-to-ore ratio into a calculation model to obtain the actual residence time and the optimal residence time, such that the residence time of nickel laterite ore in a high-pressure leaching stage can be adjusted on the basis of fluctuations in production, keeping the high-pressure acid leaching process always in the dynamic optimal state of the optimal residence time. Compared with conventional methods for optimizing the residence time by means of laboratory scale tests, the present method has the advantages of a high response speed and accurate optimization.

Description

A high-pressure leaching residence time optimization system for laterite nickel ore Technical Field

[0001] The invention relates to the technical field of high-temperature leaching of laterite nickel ore, and in particular to a high-pressure leaching residence time optimization system for laterite nickel ore. Background Art

[0002] Due to its environmental advantages, hydrometallurgical processes are increasingly being used in the metallurgical field to replace pyrometallurgical processes. Hydrometallurgical processes mainly include atmospheric leaching and pressure leaching. The pressure leaching process generally involves first slurrying the ore, then preheating the slurry, and then subjecting the preheated slurry to pressure acid leaching in an autoclave. The slurry is then cooled and depressurized, neutralized, separated, and purified.

[0003] In traditional pressure leaching processes, a large amount of steam is required to preheat the slurry to the specified temperature before entering the autoclave. This consumes a large amount of heating steam, resulting in low heat utilization efficiency, long heating time, and high heating costs. On the other hand, after high-temperature and high-pressure leaching, the leachate needs to be gradually cooled and decompressed to low-temperature atmospheric pressure in a flash tank. This process generates a large amount of flash steam, which can be mixed with the feed slurry for preheating, fully utilizing the waste heat and reducing steam usage and operating costs.

[0004] The leaching time during high-pressure acid leaching (HPAL) plays a crucial role in determining its effectiveness. Too short a leaching time can lead to incomplete leaching, low metal leaching rates, and low ore utilization. Excessive leaching time can reduce production efficiency, resulting in lower slurry throughput and output per unit time. Therefore, determining the optimal residence time for high-pressure acid leaching of laterite nickel ore and maintaining the system operating under this optimal residence time is crucial for the efficient operation of laterite nickel ore hydrometallurgy systems.

[0005] However, the optimal leaching time during high-pressure acid leaching is dynamic and is affected by a variety of factors, including leaching temperature, ore composition, feed rate, and the operating conditions of the preheating-flash system. Due to the complexity of calculating and optimizing the actual leaching time during high-pressure acid leaching, there are currently no relevant research or technical reports on optimizing the residence time in high-pressure leaching of laterite nickel ore.

[0006] Determining the optimal residence time is currently primarily done through small-scale laboratory experiments. However, due to differences in mass and heat transfer processes between small-scale and large-scale autoclaves, the optimal residence time determined in small-scale experiments differs from the optimal residence time in large-scale autoclaves. Therefore, it is impossible to fully infer the optimal residence time under large-scale autoclave operating conditions from experimental data from small-scale experiments. Due to the complexity of calculating and optimizing residence time in large-scale autoclaves, there are currently no relevant research or technical reports on residence time optimization in laterite nickel ore high-pressure leaching.

[0007] Summary of the Invention

[0008] In view of this, it is necessary to provide a laterite nickel ore high-pressure leaching residence time optimization system to determine the actual residence time and optimal residence time of the slurry in the autoclave during the high-pressure acid leaching process, so that the residence time of the laterite nickel ore high-pressure leaching link can be adjusted according to production fluctuations, so that the high-pressure acid leaching process is always in the dynamic optimal state of the optimal residence time.

[0009] In order to achieve the above object, the present invention provides a laterite nickel ore high-pressure leaching residence time optimization system, comprising a data acquisition module, an actual residence time calculation module, an optimal residence time determination module and a residence time control module;

[0010] The data acquisition module is used to collect the mass of slurry, sulfuric acid, and steam entering the autoclave per unit time during the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, the leaching temperature in the autoclave, the composition of the slurry entering the autoclave per unit time, and the prices of metallic nickel, sulfuric acid, and steam per unit mass;

[0011] The actual residence time calculation module is used to obtain the actual residence time of the slurry in the autoclave during the high-pressure acid leaching process according to the mass of the slurry, sulfuric acid, and steam entering the autoclave per unit time during the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, and the leaching temperature in the autoclave;

[0012] The optimal residence time determination module is used to obtain the optimal residence time corresponding to the maximum profit value based on the mass of the ore pulp, sulfuric acid, and steam entering the autoclave per unit time in the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, the leaching temperature in the autoclave, the composition of the ore pulp entering the autoclave per unit time, and the price of metallic nickel, sulfuric acid, and steam per unit mass;

[0013] The residence time control module is used to compare the current actual residence time with the optimal residence time under the conditions, and control the opening of the autoclave feed valve and discharge valve through the feedback control system so that the actual residence time of the slurry in the autoclave is always at the optimal residence time.

[0014] In some embodiments, the actual residence time calculation module is used to obtain the actual residence time of the slurry in the autoclave during the high-pressure acid leaching process according to the mass of the slurry, sulfuric acid, and steam entering the autoclave per unit time during the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, and the leaching temperature in the autoclave. The specific method includes:

[0015] Get the total amount of feed added in the current unit time;

[0016] Obtain the effective volume of the autoclave;

[0017] According to the leaching temperature in the autoclave, the density of the liquid at the current leaching temperature is obtained;

[0018] The actual residence time of the slurry in the autoclave is obtained based on the effective volume of the autoclave, the total amount of material added per unit time, and the liquid density at the current leaching temperature.

[0019] In some embodiments, the specific method for obtaining the total amount of material added per unit time is:

[0020] Obtain the mass of slurry, sulfuric acid and steam entering the autoclave per unit time;

[0021] The mass of steam condensed into the slurry during the steam heating process in the preheating tower per unit time is obtained according to the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank;

[0022] The total feed rate per unit time is obtained based on the mass of slurry, sulfuric acid and steam entering the autoclave per unit time and the mass of steam condensed into the slurry during steam heating in the preheating tower per unit time.

[0023] In some embodiments, the specific calculation formula for obtaining the steam mass condensed into the slurry during the steam heating process in the preheating tower per unit time is as follows based on the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank:

[0024] Among them, M 预热塔蒸汽 H is the steam mass condensed into the slurry during the steam heating process in the preheating tower per unit time, 高闪蒸汽 、H 中闪蒸汽 、H低闪蒸汽 The steam enthalpy of the outlet temperature of the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank can be obtained by combining the outlet temperature of the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank with the database. 高预液体 、H 中预液体 、H 低预液体 The liquid enthalpy of the outlet temperature of the high-temperature preheating tower, the medium-temperature preheating tower, and the low-temperature preheating tower can be obtained by combining the outlet temperature of the high-temperature preheating tower, the medium-temperature preheating tower, and the low-temperature preheating tower with the database, respectively. 高预 、T 中预 、T 低预 are the outlet temperatures of high temperature preheating tower, medium temperature preheating tower and low temperature preheating tower respectively, C p is the specific heat capacity of the slurry.

[0025] In some embodiments, the specific heat capacity of the slurry is calculated as: p =4.2*(1-c)+0.364*c

[0026] Among them, C p is the specific heat capacity of the slurry, and c is the solid content in the slurry, which can be obtained through the collected slurry flow rate and slurry concentration.

[0027] In some embodiments, the total feed amount per unit time is calculated based on the mass of slurry, sulfuric acid, and steam entering the autoclave per unit time and the mass of steam condensed into the slurry during steam heating in the preheating tower per unit time:

[0028] Among them, M total is the total amount of material added per unit time, M 矿浆 、 M 高压釜蒸汽 are the masses of slurry, sulfuric acid and steam entering the autoclave per unit time during the high-pressure leaching process, M 预热塔蒸汽 It is the mass of steam condensed into the slurry during the steam heating process in the preheating tower per unit time.

[0029] In some embodiments, the specific calculation formula for obtaining the liquid density at the current leaching temperature according to the leaching temperature in the autoclave is: ρ T =15.81747+9.87802*T-0.035239T 2 +5.38051*10 -5 T 3 -3.2612*10 -8 T 4

[0030] Among them, ρ Tis the liquid density at the current leaching temperature, and T is the current leaching temperature.

[0031] In some embodiments, the actual residence time of the slurry in the autoclave is calculated based on the effective volume of the autoclave, the total amount of material added per unit time, and the liquid density at the current leaching temperature:

[0032] Among them, t 实际 is the actual residence time of the slurry in the autoclave, V is the effective volume of the autoclave, and W is the T is the total feed flow rate, M total is the total amount of feed per unit time, ρ T is the liquid density at the current leaching temperature.

[0033] In some embodiments, the optimal residence time determination module is used to obtain the optimal residence time corresponding to the maximum profit value based on the mass of the slurry, sulfuric acid, and steam entering the autoclave per unit time in the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, the leaching temperature in the autoclave, the composition of the slurry entering the autoclave per unit time, and the price of metallic nickel, sulfuric acid, and steam per unit mass. The specific method includes:

[0034] Set different stay times in sequence;

[0035] Calculate the revenue value at each stay time;

[0036] Compare the profit values ​​at different stay times, obtain the stay time corresponding to the maximum profit value and output it.

[0037] In some embodiments, the specific formula for calculating the revenue value at each residence time is:

[0038] Among them, P Ni 、 P steam are the prices of nickel metal, sulfuric acid, and steam per unit mass, respectively. Ni is the Ni content in the slurry, M 矿浆 、 M 高压釜蒸汽 is the mass of slurry, sulfuric acid and steam entering the autoclave per unit time, X Ni is the conversion rate of Ni in the slurry, h is hours, T is the current leaching temperature, W is the mass of sulfuric acid entering the autoclave per unit time during the high-pressure leaching process, T is the total feed flow rate, t is the currently set residence time, and R is the gas constant.

[0039] In some embodiments, the residence time control module is used to compare the current actual residence time with the optimal residence time under the conditions, and control the opening of the autoclave feed valve and the discharge valve through the feedback control system so that the actual residence time of the slurry in the autoclave is always at the optimal residence time, specifically including:

[0040] If the current actual residence time is less than the optimal residence time, reducing the opening of the autoclave feed valve and / or the autoclave discharge valve;

[0041] If the current actual residence time is greater than the optimal residence time, the opening of the autoclave inlet valve and / or the autoclave outlet valve is increased.

[0042] Compared with the existing technology, the technical solution proposed in the present invention has the beneficial effect of: by inputting real-time ore composition, acid leaching temperature, acid-ore ratio and other operating conditions into the calculation model, the actual residence time and the optimal residence time are obtained, so that the residence time of the high-pressure leaching link of laterite nickel ore can be adjusted according to production fluctuations, so that the high-pressure acid leaching process is always in the dynamic optimal state of the optimal residence time. Compared with the traditional method of optimizing the residence time through small-scale experiments, this method has the advantages of fast response speed and precise optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG1 is a schematic structural diagram of an existing laterite nickel ore high temperature leaching system;

[0044] FIG2 is a schematic structural diagram of an embodiment of a system for optimizing residence time of high-pressure leaching of laterite nickel ore provided by the present invention;

[0045] FIG3 is a flow chart of a calculation method of the actual residence time calculation module in FIG2 ;

[0046] FIG4 is a schematic diagram of the process of step S110 in FIG3 ;

[0047] FIG5 is a flow chart of a calculation method for the optimal residence time determination module in FIG2 ;

[0048] In the figure: 1-preheating mechanism, 11-low-temperature preheating tower, 12-medium-temperature preheating tower, 13-high-temperature preheating tower, 2-high-pressure autoclave, 21-feed valve, 22-discharge valve, 23-steam input pipe, 3-flash mechanism, 31-low-temperature flash tank, 32-medium-temperature flash tank, 33-high-temperature flash tank, 100-data acquisition module, 200-actual residence time calculation module, 300-optimal residence time determination module, 400-residence time control module. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0050] 1 , in order to facilitate understanding of the present invention, the structure of the existing laterite nickel ore high temperature leaching system is first described.

[0051] The existing laterite nickel ore high temperature leaching system includes a preheating mechanism 1, an autoclave 2 and a flash evaporation mechanism 3;

[0052] The preheating mechanism 1 includes a plurality of low-temperature preheating towers 11, medium-temperature preheating towers 12, and high-temperature preheating towers 13 connected in series. The first medium inlet of the low-temperature preheating tower 11 is used to introduce slurry, and the first medium inlets of the medium-temperature preheating tower 12 and the high-temperature preheating tower 13 are both connected to the outlet of the previous preheating tower.

[0053] The material inlet of the autoclave 2 is connected to the outlet of the high-temperature preheating tower 13. The material inlet of the autoclave 2 is provided with a feed valve 21, and the material outlet of the autoclave 2 is provided with a discharge valve 22. The autoclave 2 is also provided with a steam input pipe 23 for introducing steam;

[0054] The flash mechanism 3 includes a low-temperature flash tank 31, a medium-temperature flash tank 32 and a high-temperature flash tank 33 connected in series in sequence. Each flash tank corresponds to each preheater one by one. The material inlet of the high-temperature flash tank 33 is connected to the material outlet of the autoclave 2, the material inlet of the medium-temperature flash tank 32 is connected to the material outlet of the high-temperature flash tank 33, the material inlet of the low-temperature flash tank 31 is connected to the material outlet of the medium-temperature flash tank 32, and the steam outlet of each flash tank is connected to the second medium inlet of the corresponding preheating tower.

[0055] 2 , the present invention provides a laterite nickel ore high-pressure leaching residence time optimization system, including a data acquisition module 100 , an actual residence time calculation module 200 , an optimal residence time determination module 300 , and a residence time control module 400 ;

[0056] The data acquisition module 100 is used to collect the mass of slurry, sulfuric acid, and steam entering the autoclave per unit time during the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, the leaching temperature in the autoclave, the composition of the slurry entering the autoclave per unit time, and the price of metallic nickel, sulfuric acid, and steam per unit mass;

[0057] The actual residence time calculation module 200 is used to calculate the actual residence time of the slurry in the autoclave during the high-pressure acid leaching process based on the mass of the slurry, sulfuric acid, and steam entering the autoclave per unit time during the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, and the leaching temperature in the autoclave;

[0058] The optimal residence time determination module 300 is used to obtain the optimal residence time corresponding to the maximum profit value based on the mass of the ore pulp, sulfuric acid, and steam entering the autoclave per unit time in the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, the leaching temperature in the autoclave, the composition of the ore pulp entering the autoclave per unit time, and the price of metallic nickel, sulfuric acid, and steam per unit mass;

[0059] The residence time control module 400 is used to compare the current actual residence time with the optimal residence time under the conditions, and control the opening of the autoclave feed valve and discharge valve through the feedback control system so that the actual residence time of the slurry in the autoclave is always at the optimal residence time.

[0060] The technical solution provided by the present invention inputs operating conditions such as real-time incoming ore composition, acid leaching temperature, and acid-ore ratio into a calculation model to derive the actual residence time and the optimal residence time. This allows the residence time of the laterite nickel ore high-pressure leaching process to be adjusted according to production fluctuations, ensuring that the high-pressure acid leaching process is always in a dynamic optimal state of the optimal residence time. Compared with the traditional method of optimizing the residence time through small-scale experiments, this method has the advantages of fast response speed and precise optimization.

[0061] In order to specifically implement the function of the actual residence time calculation module 200, please refer to Figure 3. In a preferred embodiment, the actual residence time calculation module 200 is used to obtain the actual residence time of the slurry in the autoclave during the high-pressure acid leaching process according to the mass of the slurry, sulfuric acid, and steam entering the autoclave per unit time in the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, and the leaching temperature in the autoclave. The specific method includes:

[0062] S110, obtaining the total amount of material added in the current unit time;

[0063] Referring to FIG. 4 , step S110 specifically includes:

[0064] S111. Obtain the masses of the ore pulp, sulfuric acid, and steam entering the autoclave per unit time. Since the ore pulp in the preheating tower condenses into water during the heat exchange process and the density of the ore pulp changes with temperature, the flow rate of the ore pulp fed into the autoclave and the actual volume of the ore pulp in the autoclave are fluctuating values. Accurate calculations based on various factors are required to obtain accurate values. Therefore, in addition to obtaining the masses of the ore pulp, sulfuric acid, and steam entering the autoclave per unit time, it is also necessary to obtain the mass of the steam condensed into the ore pulp during the steam heating process in the preheating tower per unit time.

[0065] S112. Determine the mass of steam condensed into the slurry during steam heating in the preheating tower per unit time based on the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank;

[0066] The specific calculation formula of step S112 is:

[0067] Among them, M 预热塔蒸汽 H is the steam mass condensed into the slurry during the steam heating process in the preheating tower per unit time, 高闪蒸汽 、H 中闪蒸汽 、H 低闪蒸汽 The steam enthalpy of the outlet temperature of the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank can be obtained by combining the outlet temperature of the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank with the database. 高预液体 、H 中预液体 、H 低预液体 are the liquid enthalpy of the outlet temperature of the high-temperature preheating tower, the medium-temperature preheating tower, and the low-temperature preheating tower, respectively, which can be obtained by combining the outlet temperature of the high-temperature preheating tower, the medium-temperature preheating tower, and the low-temperature preheating tower with the database, T 高预 、T 中预 、T 低预 are the outlet temperatures of high temperature preheating tower, medium temperature preheating tower and low temperature preheating tower respectively, C p is the specific heat capacity of the slurry.

[0068] Among them, the calculation formula of the specific heat capacity of the slurry is: C p =4.2*(1-c)+0.364*c

[0069] Among them, C p is the specific heat capacity of the slurry, and c is the solid content in the slurry, which can be obtained through the collected slurry flow rate and slurry concentration.

[0070] S113. Obtain a total feed amount per unit time based on the mass of the slurry, sulfuric acid, and steam entering the autoclave per unit time and the mass of steam condensed into the slurry during steam heating in the preheating tower per unit time.

[0071] The specific calculation formula of step S13 is:

[0072] Among them, M total is the total amount of material added per unit time, M 矿浆 、 M 高压釜蒸汽 are the masses of slurry, sulfuric acid and steam entering the autoclave per unit time during the high-pressure leaching process, M 预热塔蒸汽 It is the mass of steam condensed into the slurry during the steam heating process in the preheating tower per unit time.

[0073] S120, obtaining the effective volume of the autoclave;

[0074] S130, obtaining the liquid density at the current leaching temperature according to the leaching temperature in the autoclave;

[0075] The specific formula is: T =15.81747+9.87802*T-0.035239T 2 +5.38051*10 -5 T 3 -3.2612*10 -8 T 4

[0076] Among them, ρ T is the liquid density at the current leaching temperature, and T is the current leaching temperature.

[0077] S140 , obtaining the actual residence time of the slurry in the autoclave according to the effective volume of the autoclave, the total amount of material added per unit time, and the liquid density at the current leaching temperature.

[0078] The specific calculation formula is:

[0079] Among them, t is the actual residence time of the slurry in the autoclave, V is the effective volume of the autoclave, and W is the actual residence time of the slurry in the autoclave. T is the total feed flow rate, M total is the total amount of feed per unit time, ρ T is the liquid density at the current leaching temperature.

[0080] The actual residence time of the slurry in the autoclave can be calculated through the above steps.

[0081] In order to specifically implement the function of the optimal residence time determination module 300, please refer to Figure 5. In a preferred embodiment, the optimal residence time determination module 300 is used to obtain the optimal residence time corresponding to the maximum profit value based on the mass of the ore pulp, sulfuric acid, and steam entering the autoclave per unit time in the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, the leaching temperature in the autoclave, the composition of the ore pulp entering the autoclave per unit time, and the price of metallic nickel, sulfuric acid, and steam per unit mass. The specific method includes:

[0082] S210, setting different stay times in sequence;

[0083] S220, calculating the revenue value at each stay time;

[0084] The specific formula for calculating the revenue value at each residence time is:

[0085] Among them, P Ni 、 P steam are the prices of nickel metal, sulfuric acid, and steam per unit mass, respectively. Ni is the Ni content in the slurry, M 矿浆 、 M 高压釜蒸汽 is the mass of slurry, sulfuric acid and steam entering the autoclave per unit time, X Ni is the conversion rate of Ni in the slurry, h is hours, T is the current leaching temperature, W is the mass of sulfuric acid entering the autoclave per unit time during the high-pressure leaching process, T is the total feed flow rate, t is the currently set residence time, and R is the gas constant.

[0086] S230: Compare the revenue values ​​at various stay times, obtain the stay time corresponding to the maximum revenue value, and output it.

[0087] Through the above steps, the residence time corresponding to the maximum benefit value under the current conditions can be calculated.

[0088] In order to specifically implement the function of the residence time control module 400, referring to FIG. 2 , in a preferred embodiment, the residence time control module 400 is used to compare the current actual residence time with the optimal residence time under the conditions, and control the opening of the autoclave feed valve and the discharge valve through a feedback control system so that the actual residence time of the slurry in the autoclave is always at the optimal residence time. Specifically, the module includes:

[0089] If the current actual residence time is less than the optimal residence time, reducing the opening of the autoclave feed valve and / or the autoclave discharge valve;

[0090] If the current actual residence time is greater than the optimal residence time, the opening of the autoclave inlet valve and / or the autoclave outlet valve is increased.

[0091] In summary, the technical solution provided by the present invention inputs operating conditions such as real-time ore composition, acid leaching temperature, and acid-ore ratio into a calculation model to derive the actual residence time and the optimal residence time. This allows the residence time of the high-pressure leaching link of laterite nickel ore to be adjusted according to production fluctuations, so that the high-pressure acid leaching process is always in a dynamic optimal state of the optimal residence time. Compared with the traditional method of optimizing the residence time through small-scale experiments, this method has the advantages of fast response speed and precise optimization.

[0092] In order to verify the reliability of this technical solution, a set of verification tests was designed. The test conditions are shown in Table 1, which lists the optimal residence time under the conditions of leaching temperatures of 245°C and 250°C and an acid-ore ratio of 0.33. For the operating conditions of 250°C and an acid-ore ratio of 0.33, the optimal residence time is 50 minutes, which can increase the profit by $103 per hour compared to before optimization. For the operating conditions of 250°C and an acid-ore ratio of 0.33, the optimal residence time is 54 minutes, which can increase the profit by $7 per hour compared to before optimization. The optimal residence time will change with the set operating conditions such as leaching temperature and acid-ore ratio. After optimization using this system, the unit time profit of the high-pressure acid leaching process of laterite nickel ore can be effectively improved.

[0093] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A high pressure leaching residence time optimization system for laterite nickel ore, characterized in that: It includes a data acquisition module, an actual residence time calculation module, an optimal residence time determination module and a residence time control module; The data acquisition module is used to collect the mass of slurry, sulfuric acid and steam entering the autoclave per unit time in the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank and the low-temperature flash tank, the leaching temperature in the autoclave, the composition of the slurry entering the autoclave per unit time and the price of metal nickel, sulfuric acid and steam per unit mass; The actual residence time calculation module is used to obtain the actual residence time of the slurry in the autoclave during the high-pressure acid leaching process according to the mass of the slurry, sulfuric acid and steam entering the autoclave per unit time during the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank and the low-temperature flash tank, and the leaching temperature in the autoclave; The optimal residence time determination module is used to obtain the optimal residence time corresponding to the maximum benefit value according to the mass of slurry, sulfuric acid and steam entering the autoclave per unit time in the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank and the low-temperature flash tank, the leaching temperature in the autoclave, the composition of the slurry entering the autoclave per unit time and the price of metal nickel, sulfuric acid and steam per unit mass; The residence time control module is used to compare the current actual residence time with the optimal residence time under the conditions, and to control the opening of the autoclave feed valve and the discharge valve through the feedback control system, so that the actual residence time of the slurry in the autoclave is always at the optimal residence time.

2. The laterite nickel ore high pressure leaching residence time optimization system according to claim 1, characterized in that: The actual residence time calculation module is used to obtain the actual residence time of the slurry in the autoclave during the high-pressure acid leaching process according to the mass of the slurry, sulfuric acid, and steam entering the autoclave per unit time in the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, and the leaching temperature in the autoclave. The specific method includes: Get the total amount of feed added in the current unit time; Obtaining the effective volume of the autoclave; According to the leaching temperature in the autoclave, the density of the liquid at the current leaching temperature is obtained; The actual residence time of the slurry in the autoclave is obtained according to the effective volume of the autoclave, the total feed amount per unit time and the liquid density at the current leaching temperature.

3. The laterite nickel ore high pressure leaching residence time optimization system according to claim 2, characterized in that: The specific method to obtain the total amount of feed added per unit time is: Obtain the mass of slurry, sulfuric acid and steam entering the autoclave per unit time; The mass of steam condensed into the slurry in the preheating tower during steam heating in the preheating tower per unit time is obtained according to the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank; The total feed amount per unit time is obtained based on the mass of slurry, sulfuric acid and steam entering the autoclave per unit time and the mass of steam condensed into the slurry during steam heating in the preheating tower per unit time.

4. The laterite nickel ore high pressure leaching residence time optimization system according to claim 3, characterized in that: According to the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank, the specific calculation formula for the steam mass condensed into the slurry during the steam heating process in the preheating tower per unit time is: Among them, M 预热塔蒸汽 is the mass of steam condensed into the slurry during the steam heating process in the preheating tower per unit time, H 高闪蒸汽 , H 中闪蒸汽 , H 低闪蒸汽 The steam enthalpy of the outlet temperature of the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank can be obtained by combining the outlet temperature of the high-temperature flash tank, the medium-temperature flash tank, and the low-temperature flash tank with the database. 高预液体 , H 中预液体 , H 低预液体 are the liquid enthalpy of the outlet temperature of the high-temperature preheating tower, the medium-temperature preheating tower, and the low-temperature preheating tower, respectively, which can be obtained by combining the outlet temperature of the high-temperature preheating tower, the medium-temperature preheating tower, and the low-temperature preheating tower with the database, T 高预 、T 中预 、T 低预 are the outlet temperatures of the high temperature preheating tower, medium temperature preheating tower and low temperature preheating tower respectively, C p is the specific heat capacity of the slurry.

5. The laterite nickel ore high pressure leaching residence time optimization system according to claim 4, characterized in that: The calculation formula of the specific heat capacity of the slurry is: C p =4.2*(1-c)+0.364*c Among them, C p is the specific heat capacity of the slurry, and c is the solid content in the slurry, which can be obtained through the collected slurry flow rate and slurry concentration.

6. The laterite nickel ore high pressure leaching residence time optimization system according to claim 3, characterized in that: According to the mass of slurry, sulfuric acid and steam entering the autoclave per unit time and the mass of steam condensed into the slurry during steam heating in the preheating tower per unit time, the specific calculation formula for the total feed amount per unit time is: Among them, M total is the total amount of material added per unit time, M 矿浆 , M 高压釜蒸汽 are the masses of slurry, sulfuric acid and steam entering the autoclave per unit time during the high-pressure leaching process, M 预热塔蒸汽 It is the mass of steam condensed into the slurry during the steam heating process in the preheating tower per unit time.

7. The laterite nickel ore high pressure leaching residence time optimization system according to claim 2, characterized in that: The specific calculation formula for the liquid density at the current leaching temperature is obtained according to the leaching temperature in the autoclave: ρ T =15.81747+9.87802*T-0.035239T 2 +5.38051*10 -5 T 3 -3.2612*10 -8 T 4 Among them, ρ T is the liquid density at the current leaching temperature, and T is the current leaching temperature.

8. The laterite nickel ore high pressure leaching residence time optimization system according to claim 2, characterized in that: According to the effective volume of the autoclave, the total amount of feed per unit time and the liquid density at the current leaching temperature, the specific calculation formula for the actual residence time of the slurry in the autoclave is: Among them, t 实际 is the actual residence time of the slurry in the autoclave, V is the effective volume of the autoclave, and W is T is the total feed flow rate, M total is the total amount of feed added per unit time, ρ T is the liquid density at the current leaching temperature.

9. The laterite nickel ore high pressure leaching residence time optimization system according to claim 1, characterized in that: The optimal residence time determination module is used to obtain the optimal residence time corresponding to the maximum benefit value according to the mass of slurry, sulfuric acid and steam entering the autoclave per unit time in the high-pressure leaching process, the outlet temperatures of the high-temperature preheating tower, the medium-temperature preheating tower, the low-temperature preheating tower, the high-temperature flash tank, the medium-temperature flash tank and the low-temperature flash tank, the leaching temperature in the autoclave, the composition of the slurry entering the autoclave per unit time and the price of metal nickel, sulfuric acid and steam per unit mass. The specific method includes: Set different stay times in sequence; Calculate the revenue value at each stay time; Compare the revenue values ​​at different stay times, obtain the stay time corresponding to the maximum revenue value and output it.

10. The laterite nickel ore high pressure leaching residence time optimization system according to claim 9, characterized in that: The specific formula for calculating the revenue value at each stay time is: Among them, P Ni , P steam are the prices of nickel metal, sulfuric acid, and steam per unit mass, respectively, c Ni is the Ni content in the slurry, M 矿浆 , M 高压釜蒸汽 is the mass of slurry, sulfuric acid and steam entering the autoclave per unit time, X Ni is the conversion rate of Ni in the slurry, h is hours, T is the current leaching temperature, W is the mass of sulfuric acid entering the autoclave per unit time during the high-pressure leaching process, T is the total feed flow rate, t is the currently set residence time, and R is the gas constant.

11. The laterite nickel ore high pressure leaching residence time optimization system according to claim 1, characterized in that: The residence time control module is used to compare the current actual residence time with the optimal residence time under the conditions, and control the opening of the autoclave feed valve and the discharge valve through the feedback control system, so that the actual residence time of the slurry in the autoclave is always at the optimal residence time, specifically including: If the current actual residence time is less than the optimal residence time, reducing the opening of the autoclave feed valve and / or the autoclave discharge valve; If the current actual residence time is greater than the optimal residence time, the opening of the autoclave inlet valve and / or the autoclave outlet valve is increased.

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