Device and method for treating laterite-nickel ore through sulfuric acid method

Abstract

The invention relates to a device and method for treating laterite-nickel ore through a sulfuric acid method. The device comprises a horizontal reaction kettle, and the horizontal reaction kettle is provided with a horizontal reaction kettle body, a first feeding port, a first steam inlet and a first discharging port; the N vertical reaction kettles are connected to the first discharge port in parallel, and each vertical reaction kettle is provided with a vertical reaction kettle body, a second feed port, a second steam inlet and a second discharge port. The device disclosed by the invention can realize continuous acid process treatment of the laterite-nickel ore, and is beneficial to improving the treatment efficiency; and moreover, the leaching effect is good, and the leaching rate of nickel and cobalt reaches up to 95 wt% or above. The acidity of the obtained leachate is low, the consumption of alkali or oxide needed by follow-up neutralization treatment can be effectively reduced, the yield of neutralization residues is reduced, cost is saved, the yield of solid waste residues is reduced, and the method is more environmentally friendly.

Description

Technical Field

[0001] The invention relates to a device and a method for treating laterite nickel ore by a sulfuric acid process, belonging to the field of hydrometallurgy. Background Art

[0002] Nickel is an important metal, and laterite nickel ore is an important mineral resource for the production of nickel products. Laterite nickel ore resources are surface weathering crust deposits formed by weathering, leaching and deposition of nickel sulfide ore rock. Laterite nickel ore contains 1%-2% nickel and 20%-50% iron.

[0003] At present, most of the laterite nickel ores with high nickel content and low iron content are smelted by pyrometallurgical methods, such as rotary kiln-electric furnace smelting and sintering-blast furnace smelting, while most of the surface laterite nickel ores with low nickel content and high iron content are stockpiled. With the reduction of laterite nickel ore resources with high nickel content and low iron content, the development and utilization of a large number of stockpiled surface laterite nickel ores (low nickel and high iron) are on the agenda. The nickel of this type of surface laterite nickel ore mainly exists in the form of nickel limonite, and nickel is dispersed in the gangue minerals in the same phase. The pyrometallurgical production cost of processing this type of laterite nickel ore is high. Therefore, it is mainly treated by hydrometallurgical process, and the hydrometallurgical process mainly includes reduction roasting ammonia leaching, atmospheric pressure acid leaching and high pressure acid leaching. The reduction roasting ammonia leaching method is a combined pyrometallurgical and wet process, with high energy consumption and high production costs; a large amount of iron in the atmospheric pressure acid leaching method is leached into the solution, and the subsequent iron removal production cost is high; the high-pressure acid leaching method is divided into sulfuric acid method, nitric acid method and hydrochloric acid method. The hydrochloric acid method has the disadvantages of high iron leaching rate and easy corrosion of equipment, and the nitric acid method has the disadvantages of high-temperature calcination and decomposition of nitrates, which requires a large amount of heat source costs; the waste heat steam generated in the acid production process of the sulfuric acid method can meet production needs and has low energy consumption. Therefore, the sulfuric acid high-pressure acid leaching method is currently the mainstream wet process for treating laterite nickel ore (low nickel and high iron). When the acid method treats laterite nickel ore with high iron content, it is easy to cause the problem of iron slag deposition and scaling in the reactor during the iron precipitation process, affecting the normal operation of production. Summary of the invention

[0004] In view of the shortcomings of the prior art, one of the objects of the present invention is to provide a device for treating laterite nickel ore by a sulfuric acid method to achieve continuous production operation of the device; a second object of the present invention is to provide a method for treating laterite nickel ore by a sulfuric acid method to achieve continuous treatment of laterite nickel ore.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0006] A device for treating laterite nickel ore by sulfuric acid method, comprising:

[0007] A horizontal reactor, comprising:

[0008] A horizontal reactor body, wherein a first reaction space is defined in the horizontal reactor body, and is used for performing a first acid leaching treatment in the first reaction space and obtaining a first acid leached slurry;

[0009] A first feed inlet, which is disposed on the horizontal reactor body and communicates with the first reaction space so as to feed raw materials such as slurry and acid into the first reaction space;

[0010] a first steam inlet, which is disposed on the horizontal reactor body and communicates with the first reaction space and is used to input steam into the first reaction space;

[0011] A first discharge port, which is arranged on the horizontal reactor body and communicated with the first reaction space, and is used to discharge the first acid-leached slurry out of the first reaction space;

[0012] N vertical reactors, each of which has:

[0013] A vertical reactor body, wherein a second reaction space is defined in the vertical reactor body, and is used for performing a second acid leaching treatment in the second reaction space to obtain a second acid leached slurry;

[0014] A second feed inlet, which is arranged on the vertical reactor body and communicated with the second reaction space, and is used to input the first acid-leached slurry into the second reaction space; each second feed inlet is connected to the first discharge port;

[0015] a second steam inlet, which is disposed on the vertical reactor body and communicates with the second reaction space, and is used to input steam into the second reaction space;

[0016] A second discharge port, which is disposed on the vertical reactor body and communicates with the second reaction space, and is used to discharge the second acid-leached slurry out of the second reaction space;

[0017] Wherein, N is an integer ≥2, preferably 2-4.

[0018] In this way, the laterite nickel ore can be first subjected to high-pressure acid leaching in the horizontal reactor in the upstream section. At this time, the acidity in the reaction system is relatively high, and the iron entering the liquid phase is usually not hydrolyzed and precipitated; after the first acid leaching, the slurry enters the vertical reactor in the downstream section. During the high-pressure acid leaching, a large amount of iron continues to enter the liquid phase, and the acid in the slurry is consumed and reaches a lower acidity. At this time, the iron in the liquid phase is hydrolyzed and precipitated, and part of the iron slag produced is deposited and scaled in the vertical reactor. Since the present invention is provided with N vertical reactors connected to the first discharge port, each reactor can be used as a backup for each other and used in turn for the second acid leaching treatment and cleaning, so that the entire treatment process can be continuously and stably operated for a long time, improve the treatment efficiency and annual processing volume, and ensure a good leaching effect. Therefore, the present application can ensure a good leaching effect while realizing the continuous production operation of the device through the cooperation of the horizontal reactor and the vertical reactor.

[0019] Furthermore, the device also includes:

[0020] A flash discharging device, which is connected to each vertical reactor and is used to cool and depressurize the second acid-leached slurry to obtain a mixed slurry; and

[0021] A solid-liquid separation device is connected to the flash discharging device and is used for performing solid-liquid separation on the mixed slurry to obtain leachate and leach residue.

[0022] Furthermore, the flash discharging device includes at least two flash tanks connected in series, wherein the flash tank at the most upstream end is connected to each vertical reactor, and the flash tank at the most downstream end is connected to the solid-liquid separation device. In this way, it is convenient to carry out multi-stage flash cooling and pressure reduction treatment.

[0023] Furthermore, it also includes a steam delivery pipeline, and the first steam inlet and the second steam inlet are connected to the steam delivery pipeline.

[0024] Furthermore, a first valve is provided at the second feed port, and the inlet end of each first valve is connected to the first discharge port; a second valve is provided at the second discharge port, and the outlet end of each second valve is connected to the inlet of the flash discharge device. In this way, each vertical reactor can be conveniently turned on and off to facilitate operation or cleaning.

[0025] Furthermore, the volume of the horizontal reactor is greater than that of the vertical reactor. Preferably, the volume of the horizontal reactor is 2-6 times, more preferably 3-5 times, that of the vertical reactor.

[0026] Based on the same inventive concept, the present invention also provides a method for treating laterite nickel ore with a sulfuric acid method, which is carried out using the above-mentioned device; the method comprises the following steps:

[0027] S1. Grinding and slurrying the laterite nickel ore to be processed to obtain slurry;

[0028] S2, inputting the ore pulp into the first reaction space, performing a first acid leaching treatment, and obtaining a first acid-leached slurry at a first discharge port;

[0029] During the first acid leaching treatment, the initial concentration of sulfuric acid in the reaction system in the first reaction space is controlled to be 180-200 g / L, the temperature is 250-260° C., the pressure is 4-5 MPa, and the residence time is 0.8-1.2 h;

[0030] S3,

[0031] S3-1, inputting the first acid-leached slurry into M vertical reactors, and inputting steam into the M vertical reactors, so as to perform a second acid-leaching treatment in the second reaction space of the M vertical reactors to obtain a second acid-leached slurry;

[0032] S3-2, after the M vertical reactors have been running for a target time, stop inputting the first acid-leached slurry into the M vertical reactors, input the first acid-leached slurry into H vertical reactors among the other vertical reactors, and input steam into the H vertical reactors to perform a second acid leaching treatment in the second reaction spaces of the H vertical reactors to obtain a second acid-leached slurry; during the operation of the H vertical reactors, clean the M vertical reactors;

[0033] S3-3, after the H vertical reactors have been running for a target time, stop inputting the first acid-leached slurry into the H vertical reactors, input the first acid-leached slurry into M vertical reactors among the other vertical reactors, and input steam into the M vertical reactors to perform a second acid leaching treatment in the second reaction space of the M vertical reactors to obtain a second acid-leached slurry; while the M vertical reactors are running, clean the H vertical reactors;

[0034] S3-4, repeat S3-2 to S3-3;

[0035] During the second acid leaching treatment, the temperature in the second reaction space of the vertical reactor in operation is controlled to be 250-260°C, the pressure to be 4-5MPa, and the residence time to be 0.2-0.3h;

[0036] M is an integer ≥1 and <N; H is an integer ≥1 and ≤(NM);

[0037] S4, cooling and reducing the pressure of the slurry after the second acid leaching, and then separating the solid and the liquid to obtain the leaching solution and the leaching residue.

[0038] By controlling the relevant parameters during the first acid leaching treatment and the second acid leaching treatment, the hydrolysis, deposition and scaling of iron in the horizontal reactor on the upstream side can be effectively avoided, and the hydrolysis, deposition and scaling of iron can be caused to occur in the vertical reactor on the downstream side, and a good leaching effect can be ensured. In addition, the hydrolysis of iron means that the acidity of the slurry has been reduced to a certain extent after the first acid leaching, so the consumption of alkali or oxide required for the subsequent neutralization of the leachate can be reduced, and the amount of neutralized slag generated can be reduced, which helps to save costs and reduce the amount of solid waste slag generated.

[0039] Further, in S1, after grinding, the proportion of minerals with a particle size of ≤200 mesh in the total minerals obtained is ≥90wt%, preferably ≥95wt%;

[0040] Preferably, the iron content in the laterite nickel ore to be treated is ≥20wt%, preferably 25-60wt%, and more preferably 30-50wt%; preferably, the nickel content in the laterite nickel ore to be treated is 0.5-1.5wt%, preferably 0.8-1.3wt%; preferably, the cobalt content in the laterite nickel ore to be treated is 0.05-0.18wt%, preferably 0.08-0.15wt%.

[0041] Optionally, the nickel content in the laterite nickel ore to be treated is 0.8-1.3wt%, the cobalt content is 0.08-0.18wt%, and the iron content is 40-50wt%.

[0042] Furthermore, in S2, during the first acid leaching treatment, the initial liquid-to-solid ratio of the reaction system in the first reaction space is controlled to be 1-3 mL:1 g, preferably 1.5-2 mL:1 g.

[0043] In S3, the target time is 30-80 days, preferably 40-70 days.

[0044] Furthermore, during the first acid leaching treatment, the initial concentration of sulfuric acid in the reaction system in the first reaction space is controlled to be 185-195 g / L, the temperature is 252-258° C., the pressure is 4.2-4.8 MPa, and the residence time is 0.9-1.1 h; during the second acid leaching treatment, the temperature in the second reaction space of the vertical reactor in operation is controlled to be 252-258° C., the pressure is 4.2-4.8 MPa, and the residence time is 0.22-0.28 h.

[0045] Optionally, the temperature and pressure during the first acid leaching treatment and the second acid leaching treatment are the same.

[0046] Optionally, after S4, the following steps are also included:

[0047] S5, after performing a first neutralization treatment on the leachate, solid-liquid separation is performed to obtain a primary neutralization residue and a primary neutralization liquid;

[0048] When the first neutralization treatment is carried out, the temperature is controlled at 80-90°C, the neutralization time is 1.5-2.0h, and the reaction end point is pH 3-4; the neutralization slag can be sent to the downstream process to recover aluminum scandium;

[0049] S6, after performing a second neutralization treatment on the primary neutralized liquid, solid-liquid separation is performed to obtain a secondary neutralized slag and a secondary neutralized liquid;

[0050] When the second neutralization treatment is carried out, the temperature is controlled at 70-80°C, the neutralization time is 1.5-2.0h, and the reaction end point is pH7-8; the secondary neutralization slag is a nickel-cobalt enriched product, which can be sent to subsequent processes to recover nickel and cobalt; the secondary neutralization liquid can be returned to the first acid leaching treatment.

[0051] Optionally, magnesium oxide and / or magnesium hydroxide are used for neutralization treatment.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The device of the present invention can realize continuous acid treatment of laterite nickel ore, which is helpful to improve the treatment efficiency.

[0054] The invention has good leaching effect, and the leaching rate of nickel and cobalt is as high as more than 95wt%.

[0055] The invention can absorb the steam produced by pyrite or sulfuric acid production, and the steam supply and demand are balanced with low energy consumption.

[0056] The acidity of the leaching solution obtained by the present invention is relatively low, which can effectively reduce the consumption of alkali or oxide required for subsequent neutralization treatment and reduce the amount of neutralization slag generated, thereby helping to save costs and reduce the amount of solid waste generated, and is more green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The present invention is a process flow chart of treating laterite nickel ore by a sulfuric acid method.

[0058] Figure 2 The present invention is a simplified structural diagram of a device for treating laterite nickel ore by a sulfuric acid method. DETAILED DESCRIPTION

[0059] The present invention will be described in detail below in conjunction with the embodiments. It should be noted that the embodiments and features of the embodiments of the present invention can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear in the following, they only indicate that the upper, lower, left and right directions are consistent with the drawings themselves, and do not limit the structure. Example 1

[0060] See also Figure 2The device for treating laterite nickel ore by sulfuric acid method of this embodiment comprises:

[0061] Horizontal reactor 2, the horizontal reactor has:

[0062] A horizontal reactor body, wherein a first reaction space is defined in the horizontal reactor body, and is used for performing a first acid leaching treatment in the first reaction space and obtaining a first acid leached slurry;

[0063] A first feed inlet, which is disposed on the horizontal reactor body and communicates with the first reaction space;

[0064] A first steam inlet, which is disposed on the horizontal reactor body and communicates with the first reaction space;

[0065] A first discharge port, which is disposed on the horizontal reactor body and communicates with the first reaction space;

[0066] 2 vertical reactors 3, each of which has:

[0067] A vertical reactor body, wherein a second reaction space is defined in the vertical reactor body, and is used for performing a second acid leaching treatment in the second reaction space to obtain a second acid leached slurry;

[0068] A second feed inlet, the second feed inlet is arranged on the vertical reactor body and is connected to the second reaction space; each second feed inlet is connected to the first discharge port;

[0069] a second steam inlet, the second steam inlet being disposed on the vertical reactor body and communicating with the second reaction space;

[0070] A second discharge port, the second discharge port is disposed on the vertical reactor body and communicated with the second reaction space; and

[0071] A manhole is provided on the vertical reactor body to facilitate cleaning of the residues and dirt in the vertical reactor body.

[0072] The device also includes:

[0073] A flash discharging device 4, which is connected to each vertical reactor 3 and is used to cool and depressurize the second acid-leached slurry to obtain a mixed slurry; and

[0074] The solid-liquid separation device 5 is connected to the flash discharging device 4 and is used for performing solid-liquid separation on the mixed slurry to obtain leachate and leach residue. The solid-liquid separation device 5 includes a thickener.

[0075] The flash discharging device 4 includes three flash tanks connected in series, wherein the flash tank at the most upstream end is connected to each vertical reactor 3, and the flash tank at the most downstream end is connected to the solid-liquid separation device 5. An exhaust port is provided on the flash tank, and a sixth valve 15 is provided at the exhaust port.

[0076] It also includes a steam delivery pipeline 13 and a feed pipe 14, and a first steam inlet and a second steam inlet are connected to the steam delivery pipeline 13. The feed pipe 14 is provided with a booster pump 1. A third valve 7 is provided at the first feed inlet, and the outlet end of the feed pipe 14 is connected to the inlet of the third valve 7. A fourth valve 8 is provided at the first discharge port. A seventh valve 9 is provided at the first steam inlet, and an eighth valve 16 is provided at the second steam inlet, and the inlet end of the seventh valve 9 and the inlet end of the eighth valve 16 are connected to the steam delivery pipeline 13.

[0077] A first valve 10 is provided at the second feed port, and the inlet end of each first valve 10 is connected to the outlet end of the fourth valve 8; a second valve 11 is provided at the second discharge port, and the outlet end of each second valve 11 is connected to the inlet of the flash discharge device 4; a fifth valve 12 is provided at the inlet of the flash discharge device 4, and the outlet end of each second valve 11 is connected to the inlet end of the fifth valve 12.

[0078] Embodiment 2-4

[0079] A method for treating laterite nickel ore with a sulfuric acid method, using the device described in Example 1, comprises the following steps:

[0080] S1. Grinding the laterite nickel ore to be treated so that the proportion of minerals with a particle size of ≤200 mesh in the total amount of the obtained minerals is ≥90wt%, and then mixing with sulfuric acid solution to obtain slurry;

[0081] S2, inputting the ore pulp into the first reaction space, performing a first acid leaching treatment, and obtaining a first acid leached slurry;

[0082] S3,

[0083] S3-1, inputting the first acid-leached slurry into a vertical reactor 3 (referred to as "first vertical reactor"), and inputting steam into the first vertical reactor to perform a second acid leaching treatment in the second reaction space of the first vertical reactor to obtain a second acid-leached slurry;

[0084] S3-2, after the first vertical reactor runs for the target time, stop inputting the first acid-leached slurry into the first vertical reactor, input the first acid-leached slurry into another vertical reactor (referred to as the "second vertical reactor"), and input steam into the second vertical reactor to perform a second acid leaching treatment in the second reaction space of the second vertical reactor to obtain a second acid-leached slurry; while the second vertical reactor is running, clean the first vertical reactor through the manhole;

[0085] S3-3, after the second vertical reactor runs for a target time, stop inputting the first acid-leached slurry into the second vertical reactor, input the first acid-leached slurry into the first vertical reactor, and input steam into the first vertical reactor to perform a second acid leaching treatment in the second reaction space of the first vertical reactor to obtain a second acid-leached slurry; during the operation of the first vertical reactor, clean the second vertical reactor through the manhole;

[0086] S3-4, repeat S3-2 to S3-3;

[0087] S4, after cooling and reducing the pressure of the slurry after the second acid leaching, the solid and liquid are separated to obtain the leaching liquid and the leaching residue. The produced leaching residue is stored.

[0088] S5. Add magnesium oxide to the leachate for primary neutralization, control the temperature at 85°C, neutralization time at 2.0h, and end point pH at 3.5. After the reaction is completed, liquid-solid separation is performed, the primary neutralization slag is sent to subsequent processes to recover aluminum and scandium, and the primary neutralization liquid is sent to secondary neutralization.

[0089] S6. Add the primary neutralization liquid to magnesium oxide for secondary neutralization, control the temperature at 75°C, neutralization time for 1.8h, and end point pH 8.0. After the reaction is completed, liquid-solid separation is performed, and the secondary neutralization slag is a nickel-cobalt enriched product, which is sent to subsequent processes to recover nickel and cobalt. The secondary neutralization liquid can be returned to S1.

[0090] The relevant parameters and leaching results are shown in Table 1.

[0091] Table 1

[0092]

[0093] Note: The volume of the horizontal reactor for the first acid leaching treatment is 4×100m 3 The second acid leaching treatment vertical reactor has a volume of 100m 3 .

[0094] The results show that in the above four embodiments, no obvious scaling was observed after the horizontal reactor was continuously operated for 220 days; the cleaning cycles of the vertical reactor were 40 days, 45 days, 55 days, and 60 days, respectively.

[0095] It can be seen that by adopting the device and method of the present invention, high nickel and cobalt leaching rates can be obtained, both of which can reach more than 95wt%, and each vertical reactor can be used as a backup for each other, so that the continuous operation of the process can be achieved.

[0096] Comparative Example 1

[0097] Example 1 was repeated, except that during the first acid leaching treatment, the initial concentration of sulfuric acid in the reaction system was controlled to be 210 g / L.

[0098] As a result, the H2SO4 content of the leaching solution in S4 was 38 g / L, the Fe content was 7.4 g / L, the nickel leaching rate was 96.0%, and the cobalt leaching rate was 95.6%.

[0099] Example 5

[0100] Example 1 was repeated, except that during the first acid leaching treatment, the initial concentration of sulfuric acid in the reaction system was controlled to be 180 g / L.

[0101] As a result, the H2SO4 content of the leaching solution in S4 was 22 g / L, the Fe content was 2.4 g / L, the leaching rate of nickel was 95.2%, and the leaching rate of cobalt was 95.0%.

[0102] Comparative Example 2

[0103] Example 1 was repeated, except that during the first acid leaching treatment, the initial concentration of sulfuric acid in the reaction system was controlled to be 170 g / L.

[0104] As a result, the leaching rate of nickel was 92.8%, and the leaching rate of cobalt was 92.0%.

[0105] Comparative Example 3

[0106] Example 1 was repeated, except that during the second acid leaching treatment, the volume of the vertical reactor was 60 m 3 , the residence time during the second acid leaching treatment was controlled to be 0.14h.

[0107] As a result, the Fe content of the leaching solution in S4 was 5.8 g / L, the leaching rate of nickel was 95.3%, and the leaching rate of cobalt was 95.2%.

[0108] Comparative Example 4

[0109] Example 1 was repeated, except that during the first acid leaching treatment, the volume of the horizontal reactor was 300 m 3 , the residence time during the first acid leaching treatment was controlled to be 0.72h.

[0110] As a result, the leaching rate of nickel was 92.5%, and the leaching rate of cobalt was 91.0%.

[0111] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

Claims

1. A device for treating laterite nickel ore by sulfuric acid method, characterized in that: include: A horizontal reactor (2), wherein the horizontal reactor comprises: A horizontal reactor body, wherein a first reaction space is defined in the horizontal reactor body, and is used for performing a first acid leaching treatment in the first reaction space and obtaining a first acid leached slurry; A first feed inlet, which is disposed on the horizontal reactor body and communicates with the first reaction space; A first steam inlet, which is disposed on the horizontal reactor body and communicates with the first reaction space; A first discharge port, which is disposed on the horizontal reactor body and communicates with the first reaction space; N vertical reactors (3), wherein N is an integer ≥ 2, and the vertical reactors have: A vertical reactor body, wherein a second reaction space is defined in the vertical reactor body, and is used for performing a second acid leaching treatment in the second reaction space to obtain a second acid leached slurry; A second feed inlet, the second feed inlet is arranged on the vertical reactor body and is connected to the second reaction space; each second feed inlet is connected to the first discharge port; a second steam inlet, the second steam inlet being disposed on the vertical reactor body and communicating with the second reaction space; A second discharge port is disposed on the vertical reactor body and is communicated with the second reaction space.

2. The device for treating laterite nickel ore by sulfuric acid method according to claim 1, characterized in that: Also includes: A flash discharging device (4), which is connected to each vertical reactor (3) and is used to cool and depressurize the second acid-leached slurry to obtain a mixed slurry; as well as A solid-liquid separation device (5), the solid-liquid separation device (5) is connected to the flash discharging device (4), and is used to perform solid-liquid separation on the mixed slurry to obtain a leachate and a leachate residue.

3. The device for treating laterite nickel ore by sulfuric acid method according to claim 2, characterized in that: The flash discharging device (4) comprises at least two flash tanks connected in series; The flash tank at the most upstream end is connected to each vertical reactor (3), and the flash tank at the most downstream end is connected to the solid-liquid separation device (5).

4. The device for treating laterite nickel ore by sulfuric acid method according to claim 1, characterized in that: It also comprises a steam delivery pipeline (13), and a first steam inlet and a second steam inlet are connected to the steam delivery pipeline (13).

5. The device for treating laterite nickel ore by sulfuric acid method according to claim 1, characterized in that: A first valve (10) is provided at the second feed port, and the inlet end of each first valve (10) is connected to the first discharge port; a second valve (11) is provided at the second discharge port, and the outlet end of each second valve (11) is connected to the inlet of the flash discharge device (4).

6. A method for treating laterite nickel ore by sulfuric acid method, characterized in that: The method is carried out using the device according to any one of claims 1 to 5; comprising the following steps: S1. Grinding and slurrying the laterite nickel ore to be processed to obtain slurry; S2, inputting the slurry into the first reaction space, performing the first acid leaching treatment, and obtaining the first acid leached slurry; wherein, during the first acid leaching treatment, the initial concentration of sulfuric acid in the reaction system in the first reaction space is controlled to be 180-200 g / L, the temperature is 250-260° C., the pressure is 4-5 MPa, and the residence time is 0.8-1.2 h; S3, S3-1, inputting the first acid-leached slurry into M vertical reactors (3), and inputting steam into the M vertical reactors to perform a second acid-leaching treatment in the second reaction space of the M vertical reactors to obtain a second acid-leached slurry; S3-2, after the M vertical reactors have been running for a target time, stop inputting the first acid-leached slurry into the M vertical reactors, input the first acid-leached slurry into H vertical reactors among the other vertical reactors, and input steam into the H vertical reactors to perform a second acid leaching treatment in the second reaction spaces of the H vertical reactors to obtain a second acid-leached slurry; during the operation of the H vertical reactors, clean the M vertical reactors; S3-3, after the H vertical reactors have been running for a target time, stop inputting the first acid-leached slurry into the H vertical reactors, input the first acid-leached slurry into M vertical reactors among the other vertical reactors, and input steam into the M vertical reactors to perform a second acid leaching treatment in the second reaction space of the M vertical reactors to obtain a second acid-leached slurry; while the M vertical reactors are running, clean the H vertical reactors; S3-4, repeat S3-2 to S3-3; wherein, during the second acid leaching treatment, the temperature in the second reaction space of the vertical reactor in operation is controlled to be 250-260°C, the pressure is 4-5MPa, and the residence time is 0.2-0.3h; M is an integer ≥1 and <N; H is an integer ≥1 and ≤(NM); S4, cooling and reducing the pressure of the slurry after the second acid leaching, and then separating the solid and the liquid to obtain the leaching solution and the leaching residue.

7. The method according to claim 6, characterized in that In S1, after grinding, the proportion of minerals with a particle size of ≤200 mesh in the total minerals obtained is ≥90wt%, preferably ≥95wt%; preferably, the iron content in the laterite nickel ore to be treated is ≥20wt%, preferably 25-60wt%, more preferably 30-50wt%; preferably, the nickel content in the laterite nickel ore to be treated is 0.5-1.5wt%, preferably 0.8-1.3wt%; preferably, the cobalt content in the laterite nickel ore to be treated is 0.05-0.18wt%, preferably 0.08-0.15wt%.

8. The method according to claim 6, characterized in that In S2, during the first acid leaching treatment, the initial liquid-to-solid ratio of the reaction system in the first reaction space is controlled to be 1-3 mL:1 g, preferably 1.5-2 mL:1 g.

9. The method according to claim 6, characterized in that In S3, the target time is 30-80 days, preferably 40-70 days.

10. The method according to claim 6, characterized in that During the first acid leaching treatment, the initial concentration of sulfuric acid in the reaction system in the first reaction space is controlled to be 185-195 g / L, the temperature is 252-258° C., the pressure is 4.2-4.8 MPa, and the residence time is 0.9-1.1 h; during the second acid leaching treatment, the temperature in the second reaction space of the vertical reactor in operation is controlled to be 252-258° C., the pressure is 4.2-4.8 MPa, and the residence time is 0.22-0.28 h.

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