Laterite nickel ore hydrometallurgy pre-neutralization system and method

Abstract

A laterite nickel ore hydrometallurgy pre-neutralization system and method. The pre-neutralization system comprises an iron precipitation unit (10), a first neutralization unit (20), a second neutralization unit (30), and a control unit. The iron precipitation unit (10) receives high-pressure leaching slurry. The first neutralization unit (20) is connected to the iron precipitation unit (10) and can receive slurry formed after anhydrous sodium sulfate is supplied, and iron-aluminum slag and nickel-cobalt slag can be supplied. The second neutralization unit (30) is connected to the first neutralization unit (20). The first neutralization unit (20) can receive the slurry formed after the iron-aluminum slag and the nickel-cobalt slag are supplied, and is used for neutralizing acid in the slurry by supplying a neutralizer. The iron precipitation unit (10), the first neutralization unit (20), and the second neutralization unit (30) are arranged separately, and additionally, the control unit precisely controls the anhydrous sodium sulfate, the iron-aluminum slag, the nickel-cobalt slag and the neutralizer, so that the amounts of the added anhydrous sodium sulfate, iron-aluminum slag, nickel-cobalt slag and neutralizer can be within an appropriate range, and the economic benefit of laterite nickel ore hydrometallurgy is improved.

Description

Laterite nickel ore hydrometallurgical pre-neutralization system and pre-neutralization method Technical Field

[0001] The present invention relates to the technical field of hydrometallurgy, and in particular to a laterite nickel ore hydrometallurgy pre-neutralization system and a pre-neutralization method. Background Art

[0002] Laterite nickel ore undergoes high-pressure acid leaching to selectively leach valuable metals such as Ni (nickel) and Co (cobalt) from the raw ore, while impurities such as Fe (iron) and Al (aluminum) remain in the slag phase. The wet high-pressure acid leaching process for laterite nickel ore includes: ore dressing - high-pressure leaching - pre-neutralization - CCD countercurrent washing - 1st stage iron and aluminum precipitation - 2nd stage iron and aluminum precipitation - 1st stage nickel and cobalt precipitation - 2nd stage nickel and cobalt precipitation. After pre-neutralization, the slurry enters the CCD countercurrent washing process, where the slag in the pre-neutralization reaction tank is countercurrently washed in sequence by 6 thickeners connected in series. Finally, the underflow of the five thickeners in the CCD countercurrent washing process is discharged to the tailings filter press and finally enters the tailings pond.

[0003] For example, the patent document disclosed in the publication number CN108913883A discloses a method for producing nickel cobalt hydroxide by wet smelting of laterite nickel ore. In the production of the nickel cobalt hydroxide, the laterite nickel ore is first leached under pressure or at normal pressure to obtain a leached slurry; the leached slurry is then pre-neutralized to control the endpoint pH value to 1.1-1.8; the pre-neutralized slurry is then iron- and aluminum-removed to control the endpoint pH value to 3.5-4.2, and compressed air is introduced during the process; the slurry after iron and aluminum removal is subjected to CCD washing; the overflow after CCD washing is deeply impurity-removed to control the endpoint pH value to 4.8-5.2, and compressed air is introduced during the process; finally, the overflow after deep impurity removal is precipitated with lime milk to obtain a gypsum-nickel cobalt hydroxide mixture, and the gypsum-nickel cobalt hydroxide mixture is separated to obtain a nickel cobalt hydroxide product.

[0004] Although the existing laterite nickel ore wet smelting can achieve the control of the pH value of the slurry after high-pressure leaching through pre-neutralization treatment, thereby facilitating the production of nickel and cobalt, the pre-neutralization treatment mainly involves uniformly filling the neutralizing agents such as the second-stage iron-aluminum slag, the second-stage nickel-cobalt slag and the lime milk into the neutralization tank filled with the high-pressure leaching slurry for neutralization. As a result, the amount of the added second-stage iron-aluminum slag, the second-stage nickel-cobalt slag and the lime milk is difficult to be effectively controlled, which makes it easy to produce excessive or insufficient amounts of the added second-stage iron-aluminum slag, the second-stage nickel-cobalt slag and the lime milk, resulting in reduced economic benefits of the laterite nickel ore wet smelting.

[0005] Summary of the Invention

[0006] The object of the present invention is to overcome the above-mentioned technical deficiencies and propose a method for pre-neutralization of laterite nickel ore hydrometallurgy, so as to solve the technical problem in the prior art that it is difficult to control the addition of second-stage iron-aluminum slag, second-stage nickel-cobalt slag and lime milk during the pre-neutralization treatment of laterite nickel ore hydrometallurgy, resulting in reduced production efficiency of laterite nickel ore hydrometallurgy.

[0007] To achieve the above objectives, the technical solution of the present invention provides a laterite nickel ore hydrometallurgical pre-neutralization system, comprising:

[0008] Iron sinking unit;

[0009] A first neutralization unit connected to the iron precipitation unit;

[0010] a second neutralization unit connected to the first neutralization unit;

[0011] A control unit is connected to the first neutralization unit and the second neutralization unit, and is used to detect the pH value in the first neutralization unit and the second neutralization unit, and control the amount of iron-aluminum slag and nickel-cobalt slag added to the first neutralization unit and the amount of neutralizer added to the second neutralization unit according to the detected pH value.

[0012] Optionally, the first neutralization unit includes a feeding device, a first reaction tank and a second reaction tank, the first reaction tank is connected to the discharge end of the iron precipitation unit, the feeding device is connected to the first reaction tank, and is used to supply iron-aluminum slag and nickel-cobalt slag to the first reaction tank, the feeding end of the second reaction tank is connected to the first reaction tank, and the discharge end is connected to the second neutralization unit.

[0013] Optionally, the control unit includes a first control module and a pH monitor, the pH monitor is connected to the second reaction tank and is used to monitor the pH value of the slurry in the second reaction tank, and the first control module is connected to the pH monitor and the feeding device and is used to control the amount of iron-aluminum slag and nickel-cobalt slag supplied to the first reaction tank by the feeding device according to the pH value detected by the pH monitor.

[0014] Optionally, the second neutralization unit includes a feed pump and a third reaction tank, a fourth reaction tank and a fifth reaction tank connected in sequence, the third reaction tank is connected to the discharge end of the first neutralization unit, and the feed pump is connected to the third reaction tank and the fourth reaction tank for passing the neutralizer into the third reaction tank and the fourth reaction tank.

[0015] Optionally, the control unit further includes a second control module and a pH detector, the pH detector is connected to the fifth reaction tank, and is used to monitor the pH value of the slurry in the fifth reaction tank, and the second control module is connected to the pH detector and the feed pump, and is used to control the amount of neutralizer supplied by the feed pump to the third reaction tank and the fourth reaction tank according to the pH value detected by the pH detector.

[0016] Optionally, the iron precipitation unit includes a sixth reaction tank and a feeding device, and the feeding device is connected to the sixth reaction tank and is used to add sodium sulfate to the sixth reaction tank.

[0017] Optionally, the control unit is further used to detect the iron ion content in the sixth reaction tank and control whether the feeding device supplies sodium sulfate according to the iron ion content.

[0018] Optionally, the laterite nickel ore hydrometallurgical pre-neutralization system further includes a plurality of thickeners, each of which is arranged in sequence, the thickener at the head end is connected to the second neutralization unit, and the thickener at the tail end is used to reduce the iron ion content in the liquid phase of the bottom flow discharged from the tail end thickener and the nickel content in the solid phase by controlling the water inlet.

[0019] Compared with the prior art, the beneficial effects of the laterite nickel ore hydrometallurgical pre-neutralization system provided by the present invention include: by setting an iron precipitation unit, a first neutralization unit, a second neutralization unit and a control unit, the iron precipitation unit receives high-pressure leaching slurry, and by supplying sodium sulfate to the iron precipitation unit, the iron ion content in the received slurry is reduced; the first neutralization unit is connected to the iron precipitation unit, and can receive the slurry after the sodium sulfate is supplied, and can supply iron-aluminum slag and nickel-cobalt slag to make the iron-aluminum slag and nickel-cobalt slag react with the acid in the slurry to neutralize the slurry; The acid in the slurry simultaneously dissolves the iron and nickel in the iron-aluminum slag and the nickel-cobalt slag; the second neutralization unit is connected to the first neutralization unit, and the first neutralization unit can receive the slurry after the iron-aluminum slag and the nickel-cobalt slag are fed in, and is used to neutralize the acid in the slurry by feeding in a neutralizer. The control unit can accurately control the feeding amount of the iron-aluminum slag and the nickel-cobalt slag in the first neutralization unit and the second neutralization unit, and finally achieve accurate control of the pH value in the slurry by detecting the pH value in the first neutralization unit and the second neutralization unit.

[0020] Since the iron settling unit, the first neutralization unit and the second neutralization unit are arranged separately, the reaction conditions of the slurry inside the iron settling unit, the first neutralization unit and the second neutralization unit with the added alum, ferroaluminum slag, nickel-cobalt slag and neutralizer can be controlled by the control unit at the same time, so that the amount of the added alum, ferroaluminum slag, nickel-cobalt slag and neutralizer is within an appropriate range, thereby enabling the amount of iron ions and nickel ions in the slurry to be accurately controlled, thereby improving the economic benefits of laterite nickel ore hydrometallurgy.

[0021] To achieve the above-mentioned object, the technical solution of the present invention further provides a laterite nickel ore hydrometallurgical pre-neutralization method, which is performed by the laterite nickel ore hydrometallurgical pre-neutralization system described in the claims, comprising the following steps:

[0022] S100: passing the high-pressure leaching slurry into the iron precipitation unit;

[0023] S200: adding sodium sulfate to the iron precipitation unit to reduce the iron ion content in the slurry;

[0024] S300: Inputting the slurry treated in the sedimentation unit into the first neutralization unit, adding iron-aluminum slag and nickel-cobalt slag to the first neutralization unit, detecting the pH value in the first neutralization unit and controlling the amount of iron-aluminum slag and nickel-cobalt slag added according to the pH value;

[0025] S400: The slurry treated in the first neutralization unit is input into the second neutralization unit, a neutralizer is added to the second neutralization unit, a pH value in the second neutralization unit is detected, and an amount of the neutralizer added is controlled according to the pH value.

[0026] Optionally, the step S200 also includes: detecting the iron ion content in the iron precipitation unit and controlling whether to supply alum according to the iron ion content; wherein, when the iron ion content is greater than 1g / L, the supply of alum is controlled, and when the iron ion content is lower than 1g / L, the supply of alum is controlled to be stopped.

[0027] Optionally, step S300 includes:

[0028] The slurry treated in the sedimentation unit is fed into the first reaction tank of the first neutralization unit, and iron-aluminum slag and nickel-cobalt slag are added into the first reaction tank;

[0029] The slurry after the neutralization reaction in the first reaction tank is input into the second reaction tank of the first neutralization unit, the pH value in the second reaction tank is detected and the amount of iron-aluminum slag and nickel-cobalt slag added to the first reaction tank is controlled according to the pH value.

[0030] Optionally, detecting the pH value in the second reaction tank and controlling the amount of iron-aluminum slag and nickel-cobalt slag added to the first reaction tank according to the pH value includes:

[0031] If the pH value in the second reaction tank is detected to be higher than the first threshold range, the amount of iron-aluminum slag and nickel-cobalt slag added to the first reaction tank is controlled to increase;

[0032] If the pH value in the second reaction tank is detected to be lower than the first threshold range, the amount of iron-aluminum slag and nickel-cobalt slag added to the first reaction tank is controlled to be reduced.

[0033] Optionally, the first threshold range is 0.9 to 1.1.

[0034] Optionally, step S400 includes:

[0035] The slurry treated by the first neutralization unit is fed into the third reaction tank of the second neutralization unit, and a neutralizing agent is added to the third reaction tank;

[0036] The slurry after the neutralization reaction in the third reaction tank is fed into the fourth reaction tank of the second neutralization unit, and a neutralizing agent is added to the fourth reaction tank;

[0037] The slurry after the neutralization reaction in the fourth reaction tank is input into the fifth reaction tank of the second neutralization unit, the pH value in the fifth reaction tank is detected, and the amount of neutralizer added to the third reaction tank and the fourth reaction tank is controlled according to the pH value.

[0038] Optionally, detecting the pH value in the fifth reaction tank and controlling the amount of the neutralizer added to the third reaction tank and the fourth reaction tank according to the pH value includes:

[0039] If the pH value in the fifth reaction tank is higher than the second threshold value, the amount of the neutralizing agent added to the third reaction tank and the fourth reaction tank is controlled to increase;

[0040] If the pH value in the fifth reaction tank is detected to be lower than the second threshold range, the amount of the neutralizer added to the third reaction tank and the fourth reaction tank is controlled to be reduced.

[0041] Optionally, the second threshold range is 1.5-2.

[0042] Compared with the prior art, the beneficial effects of the laterite nickel ore hydrometallurgical pre-neutralization method provided by the present invention include: through the above-mentioned treatment method of pre-neutralization, the iron removal process of the slurry, the dissolution and neutralization process of the iron-aluminum slag and the nickel-cobalt slag, and the neutralization process of the neutralizer can be carried out independently, and then the alum, iron-aluminum slag and nickel-cobalt slag, and the neutralizer can be precisely controlled according to the reaction of the slurry inside the iron precipitation unit, the first neutralization unit and the second neutralization unit with the added alum, iron-aluminum slag and nickel-cobalt slag, and the neutralizer, and combined with the pH value in the first neutralization unit and the second neutralization unit, so that the amount of the added alum, iron-aluminum slag and nickel-cobalt slag, and the neutralizer is within an appropriate range, thereby being able to accurately control the amount of iron ions and nickel ions in the slurry, thereby improving the economic benefits of the laterite nickel ore hydrometallurgy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG1 is a schematic structural diagram of a laterite nickel ore hydrometallurgical pre-neutralization system provided in an embodiment of the present invention.

[0044] FIG2 is a flow chart of a hydrometallurgical pre-neutralization method for laterite nickel ore provided in an embodiment of the present invention.

[0045] The reference numerals in the figure are: 10 - iron precipitation unit 11 - sixth reaction tank 20 - first neutralization unit 21 - first reaction tank 22 - second reaction tank 30 - second neutralization unit 31 - third reaction tank 32 - fourth reaction tank 33 - fifth reaction tank 40 - head end thickener 50 - tail end thickener. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0047] An embodiment of the present invention provides a laterite nickel ore hydrometallurgical pre-neutralization system, which is used in the pre-neutralization treatment process of laterite nickel ore hydrometallurgy, and includes an iron precipitation unit 10, a first neutralization unit 20, a second neutralization unit 20 and a control unit (not shown in the figure), wherein the first neutralization unit 20 is connected to the iron precipitation unit 10; the second neutralization unit 30 is connected to the first neutralization unit 20; the control unit is connected to the first neutralization unit 20 and the second neutralization unit 30, and is used to detect the pH value in the first neutralization unit and the second neutralization unit, and control the amount of iron-aluminum slag and nickel-cobalt slag added to the first neutralization unit and the amount of neutralizer added to the second neutralization unit according to the detected pH value.

[0048] Specifically, by setting the iron precipitation unit 10, the first neutralization unit 20 and the second neutralization unit 30, the iron precipitation unit 10 receives the high-pressure leaching slurry, and by supplying sodium sulfate to the iron precipitation unit 10, the iron ion content in the received slurry is reduced. The first neutralization unit 20 is connected to the iron precipitation unit 10, and can receive the slurry after the sodium sulfate is supplied, and can supply iron-aluminum slag and nickel-cobalt slag to make the iron-aluminum slag and nickel-cobalt slag react with the acid in the slurry, neutralize the acid in the slurry, and dissolve the iron-aluminum slag and nickel-cobalt slag at the same time. The second neutralization unit 30 is connected to the first neutralization unit 20. The first neutralization unit 20 can receive the slurry after the iron-aluminum slag and nickel-cobalt slag are fed in, and is used to neutralize the acid in the slurry by feeding in a neutralizing agent. The control unit can accurately control the amount of iron-aluminum slag and nickel-cobalt slag fed to the first neutralization unit 20 and the second neutralization unit 30, and ultimately achieve accurate control of the pH value in the slurry by detecting the pH value in the first neutralization unit 20 and the second neutralization unit 30.

[0049] By separately setting the iron settling unit 10, the first neutralization unit 20 and the second neutralization unit 30, according to the reaction of the slurry inside the iron settling unit 10, the first neutralization unit 20 and the second neutralization unit 30 with the added alum, iron-aluminum slag and nickel-cobalt slag, and the neutralizer, at the same time, through the precise control of the alum, iron-aluminum slag and nickel-cobalt slag and the neutralizer by the control unit, the amount of the added alum, iron-aluminum slag and nickel-cobalt slag and the neutralizer is within an appropriate range, thereby being able to precisely control the amount of iron ions and nickel ions in the slurry, thereby improving the economic benefits of laterite nickel ore hydrometallurgy.

[0050] In this embodiment, the hydrometallurgy of laterite nickel ore mainly includes mineral processing-high-pressure leaching-pre-neutralization-CCD countercurrent washing-1 stage iron-aluminum precipitation-2 stages iron-aluminum precipitation-1 stage nickel-cobalt precipitation-2 stages nickel-cobalt precipitation. The pre-neutralization method is mainly used for the pre-neutralization after high-pressure leaching of the hydrometallurgy of laterite nickel ore, and the CCD countercurrent washing process. The iron-aluminum slag and nickel-cobalt slag are 2 stages of iron-aluminum slag and 2 stages of nickel-cobalt precipitation produced after 2 stages of iron-aluminum precipitation and 2 stages of nickel-cobalt precipitation. After the ore is formed into a slurry by high-pressure leaching, a slurry with a temperature of about 95°C is formed. The slurry contains iron ions and residual acid. The iron ion content of the slurry is about 5g / L, and the residual acid content is 45-50g / L.

[0051] It can be understood that the iron sinking unit 10, the first neutralization unit 20 and the second neutralization unit 30 can be composed of one or more sections of tank bodies.

[0052] In this embodiment, in the iron precipitation unit 10, the control unit controls the amount of sodium sulfate added to the slurry so that the iron ion content of the slurry after the reaction is less than 1g / L. Specifically, by controlling the iron ion content of the slurry after the reaction to be less than 1g / L, the iron ions in the slurry can be effectively removed, and the amount of sodium sulfate added can be effectively controlled to avoid excessive sodium sulfate.

[0053] In this embodiment, as shown in Figure 1, the first neutralization unit 20 includes a feeding device (not marked in the figure), a first reaction tank 21 and a second reaction tank 22. The first reaction tank 21 is connected to the discharge end of the iron precipitation unit 10, and the feeding device is connected to the first reaction tank 21 for supplying iron-aluminum slag and nickel-cobalt slag to the first reaction tank 21. The feeding end of the second reaction tank 22 is connected to the first reaction tank 21, and the discharge end of the second reaction tank is connected to the second neutralization unit 30.

[0054] Specifically, the feeding equipment can provide iron-aluminum slag and nickel-cobalt slag to the first reaction tank 21. The first reaction tank 21 can allow the iron-aluminum slag and nickel-cobalt slag to react with the slurry, dissolve the metal oxides such as iron, aluminum, nickel and cobalt in the iron-aluminum slag and nickel-cobalt slag, and form corresponding ion structures. The second reaction tank 22 can receive the slurry after the reaction. Through the sufficient reaction and standing of the first reaction tank 21, a relatively pure slurry after the reaction can be obtained.

[0055] In this embodiment, the pH value of the slurry is further controlled to be between 0.9 and 1.1 by controlling the amount of ferroaluminum slag and nickel-cobalt slag introduced. Specifically, by controlling the pH value of the slurry between 0.9 and 1.1, the slurry can achieve the maximum efficiency of dissolving the ferroaluminum slag and nickel-cobalt slag. That is, if the pH value of the slurry is higher than 1.1, it means that the amount of ferroaluminum slag and nickel-cobalt slag fed is too much, resulting in the excess ferroaluminum slag and nickel-cobalt slag being unable to be effectively dissolved under the acidic conditions. If the pH value is lower than 0.9, it means that the amount of ferroaluminum slag and nickel-cobalt slag fed is insufficient, and the acidity of the slurry can dissolve more ferroaluminum slag and nickel-cobalt slag, thereby making it impossible to fully utilize the acidity of the slurry and making it difficult to fully neutralize the acidity of the slurry with the ferroaluminum slag and nickel-cobalt slag.

[0056] In this embodiment, the control unit includes a first control module and a pH monitor. The pH monitor is connected to the second reaction tank 22 and is used to monitor the pH value of the slurry in the second reaction tank 22. The first control module is connected to the pH monitor and the feeding device and is used to control the amount of iron-aluminum slag and nickel-cobalt slag supplied to the first reaction tank 21 by the feeding device based on the pH value detected by the pH monitor.

[0057] Specifically, the pH monitor can effectively obtain the pH of the slurry after the reaction with the iron-aluminum slag and the nickel-cobalt slag by monitoring the pH value of the slurry in the second reaction tank 22. The pH monitor can automatically control the amount of iron-aluminum slag and nickel-cobalt slag added by detecting the pH value of the slurry in the second reaction tank 22 and controlling the feeding equipment by the first control module. While reducing manpower, it can effectively and accurately control the pH of the slurry after the reaction with the iron-aluminum slag and the nickel-cobalt slag, as well as the amount of iron-aluminum slag and nickel-cobalt slag added.

[0058] In this embodiment, as shown in Figure 1, the second neutralization unit 30 includes a feed pump (not marked in the figure) and a third reaction tank 31, a fourth reaction tank 32 and a fifth reaction tank 33 connected in sequence. The third reaction tank 31 is connected to the discharge end of the first neutralization unit 20, and the feed pump is connected to the third reaction tank 31 and the fourth reaction tank 32 for introducing a neutralizer into the third reaction tank 31 and the fourth reaction tank 32.

[0059] Specifically, the feed pump can provide a neutralizer to the third reaction tank 31 and the fourth reaction tank 32. The third reaction tank 31 and the fourth reaction tank 32 can provide the neutralizer to react with the slurry. After the neutralizer reacts with the slurry, the slurry is neutralized to increase the pH of the slurry. The second reaction tank 22 can receive the slurry after the reaction. Through the sufficient reaction and standing of the first reaction tank 21, a relatively pure slurry after the reaction can be obtained.

[0060] In this embodiment, further, the pH value of the slurry after adding the neutralizer is between 1.5 and 2.0.

[0061] In this embodiment, the laterite nickel ore hydrometallurgical pre-neutralization system also includes a second control module (not marked in the figure), and the control unit also includes a second control module and a pH detector. The pH detector is connected to the fifth reaction tank 33 and is used to monitor the pH value of the slurry in the fifth reaction tank 33. The second control module is connected to the pH detector and the feed pump and is used to control the amount of neutralizer supplied by the feed pump to the third reaction tank 31 and the fourth reaction tank 32 according to the pH value detected by the pH detector.

[0062] Specifically, the pH detector can effectively obtain the pH of the slurry after the reaction with the neutralizer by monitoring the pH value of the slurry in the fifth reaction tank 33. The pH detector can realize automatic control of the amount of neutralizer added by detecting the pH value of the slurry in the fifth reaction tank 33 and controlling the feeding equipment by the second control module, thereby reducing manpower and effectively and accurately controlling the pH of the slurry after the reaction with the neutralizer and the amount of neutralizer added.

[0063] In this embodiment, as shown in FIG1 , the iron precipitation unit 10 includes a sixth reaction tank 11 , which receives the high-pressure leaching slurry and allows the sodium sulfate and the high-pressure leaching slurry to react.

[0064] In this embodiment, the control unit is further configured to detect the iron ion content in the sixth reaction tank 11 and control whether the feeding device feeds glauber salt based on the iron ion content. Specifically, the control unit can accurately control the amount of glauber salt added by detecting the iron ion content.

[0065] In this embodiment, through the setting of the controller, feeding equipment, detection module, pH monitor, feeding equipment, pH detector and feed pump, the entire pre-neutralization process can be automatically controlled, thereby effectively reducing the manpower consumed in the pre-neutralization process.

[0066] In this embodiment, as shown in FIG1 , the laterite nickel ore hydrometallurgical pre-neutralization system further includes a plurality of thickeners, which are arranged in sequence. The head-end thickener is connected to the second neutralization unit 30. The tail-end thickener 50 is configured to reduce the iron ion content in the liquid phase of the underflow discharged from the tail-end thickener 50 and the nickel content in the solid phase by controlling the water inflow. Specifically, by controlling the water inflow of the tail-end thickener 50, the liquid phase of the underflow discharged from the tail-end thickener 50 can be adjusted to a ratio between 50% and 60%. By detecting the iron ions in the liquid phase of the underflow and the nickel in the solid phase, the iron and nickel ion contents in the slurry in the tail-end thickener 50 can be relatively accurately reflected, thereby effectively reflecting the amount of iron, nickel, and cobalt overflowing from a single thickener.

[0067] In this embodiment, further, as shown in Figure 1, the number of thickeners is 6, the head-end thickener 40 is connected to the fifth reaction tank 33, and the bottom flow discharged from each thickener flows into the next thickener until it enters the tail-end thickener 50 and is discharged from the tail-end thickener 50; the clean water is added to the tail-end thickener 50, and will overflow from the tail-end thickener 50 in sequence until it enters the head-end thickener 40, and finally enters the iron precipitation workshop from the head-end thickener 40.

[0068] An embodiment of the present invention further provides a laterite nickel ore hydrometallurgical pre-neutralization method, which is performed by the laterite nickel ore hydrometallurgical pre-neutralization system, as shown in FIG2 , and includes the following steps:

[0069] S100: passing the high-pressure leaching slurry into the iron precipitation unit 10;

[0070] S200: adding sodium sulfate to the iron precipitation unit 10 to reduce the iron ion content in the slurry;

[0071] S300: The slurry treated in the sedimentation unit 10 is fed into the first neutralization unit 20, iron-aluminum slag and nickel-cobalt slag are added to the first neutralization unit 20, the pH value in the first neutralization unit 20 is detected, and the amount of iron-aluminum slag and nickel-cobalt slag added is controlled according to the pH value;

[0072] S400: The slurry treated by the first neutralization unit 20 is input into the second neutralization unit 30, a neutralizer is added to the second neutralization unit 30, a pH value in the second neutralization unit 30 is detected, and the amount of the neutralizer added is controlled according to the pH value.

[0073] Specifically, through the above treatment method of pre-neutralization, the iron removal process of the slurry, the dissolution and neutralization process of the iron-aluminum slag and the nickel-cobalt slag, and the neutralization process of the neutralizer can be carried out independently, and then according to the reaction of the slurry inside the iron precipitation unit 10, the first neutralization unit 20 and the second neutralization unit 30 with the added alum, iron-aluminum slag and nickel-cobalt slag, and the neutralizer, and combined with the pH value in the first neutralization unit 20 and the second neutralization unit 30, the alum, iron-aluminum slag and nickel-cobalt slag, and the neutralizer can be precisely controlled so that the amount of added alum, iron-aluminum slag and nickel-cobalt slag, and the neutralizer is within an appropriate range, thereby being able to precisely control the amount of iron ions and nickel ions in the slurry, thereby improving the economic benefits of laterite nickel ore hydrometallurgy.

[0074] In this embodiment, in step S300, the pH value of the slurry after the addition of the ferroaluminum slag and the nickel-cobalt slag is monitored online by a pH monitor. The first control module controls the feeding device to reduce or increase the amount of the ferroaluminum slag and the nickel-cobalt slag introduced based on the pH value monitored by the pH monitor, so as to control the pH value monitored by the pH monitor to be within a first threshold range, wherein the first threshold range is between 0.9 and 1.1. Specifically, by monitoring the pH value of the slurry after the addition of the ferroaluminum slag and the nickel-cobalt slag by the pH monitor and controlling the amount of the ferroaluminum slag and the nickel-cobalt slag introduced by the first control module, automatic control of the efficient feeding process of the ferroaluminum slag and the nickel-cobalt slag can be achieved, thereby effectively reducing the intensity of the pre-neutralization process.

[0075] In this embodiment, further, the slurry is introduced into the first reaction tank 21 after reacting in the sixth reaction tank 11. The first reaction tank 21 is used to provide the iron-aluminum slag and the nickel-cobalt slag for the reaction with the slurry. The second reaction tank 22 receives the slurry in the first reaction tank 21 after the reaction with the iron-aluminum slag and the nickel-cobalt slag. The pH monitor is connected to the second reaction tank 22 to monitor the pH value of the slurry after the reaction with the iron-aluminum slag and the nickel-cobalt slag in real time.

[0076] If the pH value in the second reaction tank is detected to be higher than the first threshold range, the amount of iron-aluminum slag and nickel-cobalt slag added to the first reaction tank is controlled to increase;

[0077] If the pH value in the second reaction tank is detected to be lower than the first threshold range, the amount of iron-aluminum slag and nickel-cobalt slag added to the first reaction tank is controlled to be reduced.

[0078] That is, when the pH value monitored by the pH monitor is less than 0.9, the first control module controls the feeding equipment to increase the amount of iron-aluminum slag and nickel-cobalt slag fed into the second reaction tank 22; when the pH value monitored by the pH monitor is greater than 1.1, the first control module controls the feeding equipment to reduce the amount of iron-aluminum slag and nickel-cobalt slag fed into the second reaction tank 22.

[0079] In this embodiment, in step S500, a pH detector detects the pH value of the slurry after the addition of the neutralizer. The second control module controls the feed pump to reduce or increase the amount of neutralizer added based on the pH value detected by the pH detector, thereby controlling the pH value detected by the pH detector to be within a second threshold range, wherein the second threshold range is between 1.5 and 2.0. Specifically, by monitoring the pH value of the slurry after the addition of the neutralizer by the pH detector and controlling the amount of neutralizer introduced by the feed pump by the second control module, automatic control of the slurry neutralization process can be achieved, thereby effectively reducing the intensity of the pre-neutralization process.

[0080] In this embodiment, further, after being monitored in the second reaction tank 22, the slurry enters the third reaction tank 31, the fourth reaction tank 32, and the fifth reaction tank in sequence, a neutralizer is added to the third reaction tank 31 and the fourth reaction tank 32, and a pH detector detects the pH value of the slurry in the fourth reaction tank 32 and the fifth reaction tank;

[0081] If the pH value in the fifth reaction tank detected by the pH detector is higher than the second threshold range, the amount of the neutralizer added to the third reaction tank and the fourth reaction tank is controlled to increase;

[0082] If the pH value in the fifth reaction tank detected by the pH detector is lower than the second threshold range, the amount of the neutralizer added to the third reaction tank and the fourth reaction tank is controlled to be reduced.

[0083] That is, when the pH value monitored by the pH detector is less than 1.5, the second control module controls the feed pump to increase the amount of neutralizer fed into the third reaction tank 31 and the fourth reaction tank 32; when the pH value monitored by the pH detector is greater than 2.0, the second control module controls the feed pump to reduce the amount of neutralizer fed into the third reaction tank 31 and the fourth reaction tank 32.

[0084] In this embodiment, in step S200, the detection module detects the iron ion content in the slurry after the addition of sodium sulfate, and controls whether to feed sodium sulfate according to the iron ion content; when the detection module detects that the iron ion content is greater than 1g / L, the control unit controls the feeding device to feed sodium sulfate into the slurry; when the detection module detects that the iron ion content is less than 1g / L, the control unit controls the feeding device to stop feeding sodium sulfate into the slurry. Specifically, by monitoring the iron ion content by the detection module and controlling the amount of sodium sulfate introduced into the feeding device by the control unit, automatic control of the iron ion treatment process in the slurry can be achieved, thereby effectively reducing the intensity of the pre-neutralization process.

[0085] In this embodiment, further, the detection module and the feeding equipment are connected to the sixth reaction tank 11. When the iron ion content detected by the detection module is less than 1g / L, the control unit controls the feeding equipment to reduce the amount of alum fed to the sixth reaction tank 11. When the iron ion content detected by the detection module is greater than 1g / L, the control unit controls the feeding equipment to increase the amount of alum fed to the sixth reaction tank 11.

[0086] In this embodiment, the detection module can be a 3S-CL-Fe iron ion online analyzer, which detects the content of iron ions in the sixth reaction tank 11 through online sampling and analysis by the online analyzer, or through a color reaction, 1,10-phosphdiazoxide reacts with the iron ions in the sampled solution to turn into an orange solution; or the iron ion content is determined by quantitative analysis of absorbance; or through a combination of an online analyzer, a color reaction and absorbance determination.

[0087] In this embodiment, in step S400, the iron ion content in the liquid phase of the underflow discharged from the tail-end thickener 50 is less than 0.08 g / L, and the mass fraction of nickel in the solid phase is less than 0.06%. Specifically, by controlling the iron ion content in the liquid phase of the underflow discharged from the thickener to less than 0.08 g / L and the mass fraction of nickel in the solid phase to less than 0.06%, the iron and nickel contents in the discharged underflow can be controlled at low levels, thereby controlling the iron and nickel ion contents in the slurry discharged from the head-end thickener 40 to high levels.

[0088] In this embodiment, in step S500, the neutralizing agent is one or more of limestone, lime milk, and sodium hydroxide. Specifically, by providing a combination of one or more of limestone, lime milk, and sodium hydroxide, efficient neutralization of the slurry can be achieved.

[0089] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A laterite nickel ore hydrometallurgical pre-neutralization system, characterized in that: include: Iron sinking unit; A first neutralization unit connected to the iron precipitation unit; A second neutralization unit connected to the first neutralization unit; A control unit is connected to the first neutralization unit and the second neutralization unit, and is used to detect the pH value in the first neutralization unit and the second neutralization unit, and control the amount of iron-aluminum slag and nickel-cobalt slag added to the first neutralization unit and the amount of neutralizer added to the second neutralization unit according to the detected pH value.

2. The laterite nickel ore hydrometallurgical pre-neutralization system according to claim 1, characterized in that: The first neutralization unit includes a feeding device, a first reaction tank and a second reaction tank. The first reaction tank is connected to the discharge end of the iron precipitation unit. The feeding device is connected to the first reaction tank and is used to supply iron-aluminum slag and nickel-cobalt slag to the first reaction tank. The feeding end of the second reaction tank is connected to the first reaction tank, and the discharge end is connected to the second neutralization unit.

3. The laterite nickel ore hydrometallurgical pre-neutralization system according to claim 2, characterized in that: The control unit includes a first control module and a pH monitor, wherein the pH monitor is connected to the second reaction tank and is used to monitor the pH value of the slurry in the second reaction tank, and the first control module is connected to the pH monitor and the feeding device and is used to control the amount of iron-aluminum slag and nickel-cobalt slag supplied to the first reaction tank by the feeding device according to the pH value detected by the pH monitor.

4. The laterite nickel ore hydrometallurgical pre-neutralization system according to claim 1, characterized in that: The second neutralization unit includes a feed pump and a third reaction tank, a fourth reaction tank and a fifth reaction tank connected in sequence, the third reaction tank is connected to the discharge end of the first neutralization unit, and the feed pump is connected to the third reaction tank and the fourth reaction tank for passing a neutralizer into the third reaction tank and the fourth reaction tank.

5. The laterite nickel ore hydrometallurgical pre-neutralization system according to claim 4, characterized in that: The control unit also includes a second control module and a pH detector, wherein the pH detector is connected to the fifth reaction tank and is used to monitor the pH value of the slurry in the fifth reaction tank, and the second control module is connected to the pH detector and the feed pump and is used to control the amount of neutralizer supplied by the feed pump to the third reaction tank and the fourth reaction tank according to the pH value detected by the pH detector.

6. The laterite nickel ore hydrometallurgical pre-neutralization system according to claims 1 to 5, characterized in that: The iron precipitation unit comprises a sixth reaction tank and a feeding device, wherein the feeding device is connected to the sixth reaction tank and is used for adding sodium sulphate to the sixth reaction tank.

7. The laterite nickel ore hydrometallurgical pre-neutralization system according to claim 6, characterized in that: The control unit is also used to detect the iron ion content in the sixth reaction tank and control whether the feeding device supplies sodium sulfate according to the iron ion content.

8. The laterite nickel ore hydrometallurgical pre-neutralization system according to any one of claims 1 to 5, characterized in that: The laterite nickel ore hydrometallurgical pre-neutralization system also includes a plurality of thickeners, which are arranged in sequence. The thickener at the head end is connected to the second neutralization unit, and the thickener at the tail end is used to reduce the iron ion content in the liquid phase of the bottom flow discharged from the thickener at the tail end and the nickel content in the solid phase by controlling the water intake.

9. A hydrometallurgical pre-neutralization method for laterite nickel ore, characterized in that: The method is performed by the laterite nickel ore hydrometallurgical pre-neutralization system according to any one of claims 1 to 8, comprising the following steps: S100: passing the high-pressure leaching slurry into the iron precipitation unit; S200: adding sodium sulfate to the iron precipitation unit to reduce the iron ion content in the slurry; S300: inputting the slurry treated by the sedimentation unit into the first neutralization unit, adding iron-aluminum slag and nickel-cobalt slag to the first neutralization unit, detecting the pH value in the first neutralization unit and controlling the amount of iron-aluminum slag and nickel-cobalt slag added according to the pH value; S400: inputting the slurry treated by the first neutralization unit into the second neutralization unit, adding a neutralizer to the second neutralization unit, detecting the pH value in the second neutralization unit and controlling the amount of the neutralizer added according to the pH value.

10. The hydrometallurgical pre-neutralization method of laterite nickel ore according to claim 9, characterized in that: The step S200 also includes: detecting the iron ion content in the iron precipitation unit and controlling whether to supply alum according to the iron ion content; wherein, when the iron ion content is greater than 1g / L, the supply of alum is controlled, and when the iron ion content is lower than 1g / L, the supply of alum is controlled to be stopped.

11. The hydrometallurgical pre-neutralization method of laterite nickel ore according to claim 9, characterized in that: The step S300 includes: The slurry treated by the sedimentation unit is input into the first reaction tank of the first neutralization unit, and iron-aluminum slag and nickel-cobalt slag are added into the first reaction tank; The slurry after the neutralization reaction in the first reaction tank is input into the second reaction tank of the first neutralization unit. The pH value in the second reaction tank is detected and the amount of iron-aluminum slag and nickel-cobalt slag added to the first reaction tank is controlled according to the pH value.

12. The hydrometallurgical pre-neutralization method of laterite nickel ore according to claim 11, characterized in that: The method of detecting the pH value in the second reaction tank and controlling the amount of iron-aluminum slag and nickel-cobalt slag added to the first reaction tank according to the pH value comprises: If the pH value in the second reaction tank is detected to be higher than the first threshold range, the amount of iron-aluminum slag and nickel-cobalt slag added to the first reaction tank is controlled to increase; If the pH value in the second reaction tank is detected to be lower than the first threshold range, the amount of iron-aluminum slag and nickel-cobalt slag added to the first reaction tank is controlled to be reduced.

13. The hydrometallurgical pre-neutralization method of laterite nickel ore according to claim 12, characterized in that: The first threshold ranges from 0.9 to 1.

1.

14. The hydrometallurgical pre-neutralization method of laterite nickel ore according to claim 9, characterized in that: The step S400 includes: The slurry treated by the first neutralization unit is input into the third reaction tank of the second neutralization unit, and a neutralizing agent is added into the third reaction tank; The slurry after the neutralization reaction in the third reaction tank is input into the fourth reaction tank of the second neutralization unit, and a neutralizing agent is added into the fourth reaction tank; The slurry after the neutralization reaction in the fourth reaction tank is input into the fifth reaction tank of the second neutralization unit, the pH value in the fifth reaction tank is detected, and the amount of the neutralizing agent added to the third reaction tank and the fourth reaction tank is controlled according to the pH value.

15. The hydrometallurgical pre-neutralization method of laterite nickel ore according to claim 14, characterized in that: The method of detecting the pH value in the fifth reaction tank and controlling the amount of the neutralizing agent added to the third reaction tank and the fourth reaction tank according to the pH value comprises: If the pH value in the fifth reaction tank is higher than the second threshold value, the amount of the neutralizing agent added to the third reaction tank and the fourth reaction tank is controlled to increase; If the pH value in the fifth reaction tank is detected to be lower than the second threshold range, the amount of the neutralizing agent added to the third reaction tank and the fourth reaction tank is controlled to be reduced.

16. The hydrometallurgical pre-neutralization method of laterite nickel ore according to claim 15, characterized in that: The second threshold range is 1.5-2.

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