A device for preheating slurry in a high-pressure acid leaching process of laterite nickel ore

Abstract

This utility model discloses a device for preheating slurry in the high-pressure acid leaching process of laterite nickel ore. It includes a thickener connected to a high-pressure acid leaching feed tank. The lower wall of the high-pressure acid leaching feed tank is connected to the upper wall of a low-temperature preheater via a first slurry pipe. The top of the low-temperature preheater is connected to the top of the high-pressure acid leaching feed tank via a first exhaust pipe. The bottom of the low-temperature preheater is connected to the upper wall of a medium-temperature preheater via a second slurry pipe. The top of the medium-temperature preheater is connected to a second exhaust pipe, which is divided into a first exhaust pipe and a second exhaust pipe. The first exhaust pipe leads to the high-pressure acid leaching feed tank, and the second exhaust pipe leads to the tail gas scrubbing area. This utility model uses a thickener with high walls and a large cone angle to increase the underflow concentration of the slurry. By recovering the heat from the exhaust steam of the preheater to heat the slurry, it can simultaneously increase the slurry concentration and temperature while ensuring that the slurry rheology meets the conveying requirements, thus improving production and efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of non-ferrous metal metallurgy technology, and relates to the smelting technology of laterite nickel ore, specifically to a device for preheating ore slurry in the high-pressure acid leaching process of laterite nickel ore. Background Technology

[0002] Laterite nickel ore is a major raw material for producing nickel and cobalt. Currently, there are two main smelting technologies for laterite nickel ore: hydrometallurgical and pyrometallurgical processes. The pyrometallurgical process, primarily the RKEF process, produces ferronickel. Pyrometallurgical processes require high-grade nickel ore, involve large investments in equipment, high energy consumption, and severe pollution. With the increasing depletion of high-grade laterite nickel ore through mining, hydrometallurgical processes have become the mainstream technology for smelting low-grade laterite nickel ore. Hydrometallurgical smelting mainly employs pressure acid leaching.

[0003] The pressurized acid leaching process for laterite nickel ore is as follows: After washing and beneficiation, the laterite nickel ore is prepared into a qualified slurry (10% concentration). This slurry is then concentrated to a concentration of 38% using a thickener and pumped to a "three-stage preheater + pressurized kettle + three-stage flash tank" section. The slurry, after reaction in the pressurized kettle, is depressurized and cooled in the flash tank before being sent to the subsequent neutralization and impurity removal section to extract valuable metals such as nickel and cobalt. The secondary steam generated in the flash tank is sent to the preheater, where it directly exchanges heat with the slurry counter-currently, raising the slurry temperature to approximately 200°C through the three-stage preheating process. The slurry is then pumped to the pressurized kettle by a high-temperature diaphragm pump. The low-temperature, medium-temperature, and high-temperature preheaters use the secondary steam produced by the low-pressure, medium-pressure, and high-pressure flash tanks, respectively, as a heat source to heat the slurry. The exhaust steam from the low-temperature, medium-temperature, and high-temperature preheaters is discharged to a tail gas scrubbing device.

[0004] Due to the characteristics of laterite nickel ore slurry, when the slurry concentration exceeds 38%, the yield stress and stiffness coefficient of the slurry increase significantly, greatly affecting fluid transport and thus limiting the production capacity of laterite nickel ore hydrometallurgical. Furthermore, the exhaust steam from the low-temperature, medium-temperature, and high-temperature preheaters is sent to the tail gas scrubbing unit without recovering the heat, resulting in energy waste. Finally, the tail gas scrubbing unit treats the exhaust steam from the low-temperature, medium-temperature, and high-temperature preheaters, as well as the autoclave, and is a large-scale unit. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, this utility model proposes a device for preheating the slurry in the high-pressure acid leaching process of laterite nickel ore, so as to solve the technical problem of low production capacity in the high-pressure acid leaching process of laterite nickel ore in the existing technology.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A device for preheating slurry in the high-pressure acid leaching process of laterite nickel ore is characterized in that it includes a thickener connected to a high-pressure acid leaching feed tank, the lower side wall of the high-pressure acid leaching feed tank being connected to the upper side wall of a low-temperature preheater through a first slurry pipe, and the top of the low-temperature preheater being connected to the top of the high-pressure acid leaching feed tank through a first exhaust pipe.

[0008] The bottom of the low-temperature preheater is connected to the upper side wall of the medium-temperature preheater through the second slurry pipe. The top of the medium-temperature preheater is connected to one end of the second exhaust pipe. The other end of the second exhaust pipe is divided into a first exhaust branch pipe and a second exhaust branch pipe. The first exhaust branch pipe leads to the high-pressure acid leaching feed tank, and the second exhaust branch pipe leads to the tail gas scrubbing area.

[0009] This utility model also has the following technical features:

[0010] The height of the thickener's tank wall is between 4 and 8 meters, and the cone angle of the thickener is between 20° and 30°.

[0011] The bottom of the medium-temperature preheater is connected to the upper side wall of the high-temperature preheater through a third slurry pipe, the bottom of the high-temperature preheater is connected to the high-pressure vessel through a high-temperature preheating pipe, and the top of the high-temperature preheater is connected to the exhaust gas scrubbing area through a third exhaust pipe.

[0012] The first exhaust branch pipe is equipped with a first gate valve and a first pressure reducing valve in sequence, with the first gate valve located on the side closer to the second exhaust pipe.

[0013] The second exhaust branch pipe is equipped with a second gate valve, an electric regulating valve, a third gate valve and a fourth gate valve in sequence. The second gate valve, the electric regulating valve and the third gate valve are connected in series, and the second gate valve, the electric regulating valve and the third gate valve are connected in parallel with the fourth gate valve. The second gate valve is located on the other side near the second exhaust pipe.

[0014] The electric regulating valve is electrically connected to the temperature transmitter.

[0015] Low-pressure flash steam is introduced into the low-temperature preheater, medium-pressure flash steam is introduced into the medium-temperature preheater, and high-pressure flash steam is introduced into the high-temperature preheater.

[0016] The first slurry pipeline is equipped with one slurry pump, the second slurry pipeline is equipped with two slurry pumps in sequence, and the third slurry pipeline is equipped with three slurry pumps in sequence.

[0017] A high-temperature diaphragm pump is installed on the high-temperature preheating pipeline.

[0018] A pressure detection valve is installed on the second exhaust pipe.

[0019] The thickener is connected to the high-pressure acid leaching feed tank via a feed pipe, and a slurry pump is also installed on the feed pipe.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] (I) The device for preheating slurry in the high-pressure acid leaching process of laterite nickel ore proposed in this utility model adopts a slurry preheating method that, without changing the existing main process flow and without requiring an external heat source, uses a thickener with high pool walls (4-8m) and a large cone angle (20-30°) to increase the slurry underflow concentration to 40-45%. The slurry is heated by recovering the exhaust heat of the preheater. This method can simultaneously increase the slurry concentration and temperature while ensuring that the slurry rheology meets the transportation requirements, thereby increasing the device's capacity by about 10% and playing a role in improving production and efficiency.

[0022] (II) The device for preheating slurry in the high-pressure acid leaching process of laterite nickel ore proposed in this utility model can reduce the amount of waste gas sent to the tail gas scrubbing process, reduce the scale of tail gas scrubbing, and reduce the initial investment cost of tail gas scrubbing equipment and civil engineering. Therefore, this utility model has significant advantages in energy saving, emission reduction and investment saving, and provides a reliable technical solution for improving the production and efficiency of the high-pressure acid leaching process of laterite nickel ore. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the slurry preheating device in the high-pressure acid leaching process of laterite nickel ore.

[0024] The meanings of the labels in the diagram are as follows: 1-thickener, 2-high-pressure acid leaching feed tank, 3-first slurry pipeline, 4-low temperature preheater, 5-first exhaust steam pipeline, 6-second slurry pipeline, 7-medium temperature preheater, 8-second exhaust steam pipeline, 9-third slurry pipeline, 10-high temperature preheater, 11-high temperature preheating pipeline, 12-pressure vessel, 13-third exhaust steam pipeline, 14-temperature transmitter, 15-slurry pump, 16-high temperature diaphragm pump, 17-pressure detection valve, 18-feed pipeline.

[0025] 801 - First steam branch pipe, 802 - Second steam branch pipe.

[0026] 80101 - First gate valve, 80102 - First pressure reducing valve, 80201 - Second gate valve, 80202 - Electric regulating valve, 80203 - Third gate valve, 80204 - Fourth gate valve.

[0027] The specific content of this utility model will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, all equipment and materials used in this invention are those known in the prior art. The thickener, high-pressure acid leaching feed tank, and high-pressure autoclave in this invention are all equipped with a stirrer as needed.

[0029] The principle of this invention is that as the temperature of laterite nickel ore slurry increases, the viscosity of the slurry gradually decreases, the interaction between particles weakens, the stiffness coefficient decreases, and the slurry fluidity increases. Therefore, the slurry concentration can be increased within a certain range, and the slurry can be heated to 40℃~80℃, so that the rheological properties of the high-temperature, high-concentration slurry are comparable to those of the room-temperature, 38% concentration slurry, thus meeting the transportation requirements.

[0030] Following the above technical solution, the following are specific embodiments of this utility model. It should be noted that this utility model is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solution of this application fall within the protection scope of this utility model.

[0031] Example:

[0032] This embodiment proposes a device for preheating the ore slurry in the high-pressure acid leaching process of laterite nickel ore, such as... Figure 1 As shown, it includes a thickener 1, which is connected to a high-pressure acid leaching feed tank 2. The lower side wall of the high-pressure acid leaching feed tank 2 is connected to the upper side wall of a low-temperature preheater 4 through a first slurry pipe 3. The top of the low-temperature preheater 4 is connected to the top of the high-pressure acid leaching feed tank 2 through a first exhaust pipe 5.

[0033] like Figure 1 As shown, the bottom of the low-temperature preheater 4 is connected to the upper side wall of the medium-temperature preheater 7 through the second slurry pipe 6. The top of the medium-temperature preheater 7 is connected to one end of the second exhaust pipe 8. The other end of the second exhaust pipe 8 is divided into a first exhaust branch pipe 801 and a second exhaust branch pipe 802. The first exhaust branch pipe 801 leads to the high-pressure acid leaching feed tank 2, and the second exhaust branch pipe 802 leads to the tail gas scrubbing area.

[0034] As a preferred embodiment, the height of the tank wall of the thickener 1 is between 4 and 8 m, and the cone angle of the thickener 1 is between 20° and 30°.

[0035] As a preferred embodiment of this invention, such as Figure 1 As shown, the bottom of the medium-temperature preheater 7 is connected to the upper side wall of the high-temperature preheater 10 through the third slurry pipe 9, the bottom of the high-temperature preheater 10 is connected to the high-pressure vessel 12 through the high-temperature preheating pipe 11, and the top of the high-temperature preheater 10 is connected to the tail gas scrubbing area through the third exhaust pipe 13.

[0036] As a preferred embodiment of this invention, such as Figure 1As shown, a first gate valve 80101 and a first pressure reducing valve 80102 are sequentially installed on the first exhaust steam branch pipe 801. The first gate valve 80101 is located on the side close to the second exhaust steam pipe 8.

[0037] As a preferred embodiment of this invention, such as Figure 1 As shown, a second gate valve 80201, an electric regulating valve 80202, a third gate valve 80203, and a fourth gate valve 80204 are sequentially installed on the second exhaust branch pipe 802. The second gate valve 80201, the electric regulating valve 80202, and the third gate valve 80203 are connected in series, and the second gate valve 80201, the electric regulating valve 80202, and the third gate valve 80203 are connected in parallel with the fourth gate valve 80204. The second gate valve 80201 is located on the other side near the second exhaust pipe 8.

[0038] As a preferred embodiment of this invention, such as Figure 1 As shown, the electric regulating valve 80202 is electrically connected to the temperature transmitter 14.

[0039] As a preferred embodiment of this invention, such as Figure 1 As shown, low-pressure flash steam is introduced into the low-temperature preheater 4, medium-pressure flash steam is introduced into the medium-temperature preheater 7, and high-pressure flash steam is introduced into the high-temperature preheater 10.

[0040] As a preferred embodiment of this invention, such as Figure 1 As shown, a slurry pump 15 is installed on the first slurry pipe 3, two slurry pumps 15 are installed on the second slurry pipe 6 in sequence, and three slurry pumps 15 are installed on the third slurry pipe 9 in sequence.

[0041] As a preferred embodiment of this invention, such as Figure 1 As shown, a high-temperature diaphragm pump 16 is installed on the high-temperature preheating pipeline 11.

[0042] As a preferred embodiment of this invention, such as Figure 1 As shown, a pressure detection valve 17 is installed on the second exhaust pipe 8.

[0043] As a preferred embodiment of this invention, such as Figure 1 As shown, the thickener 1 is connected to the high-pressure acid leaching feed tank 2 through the feed pipe 18, and a slurry pump 15 is also installed on the feed pipe 18.

[0044] In this preferred embodiment, the method for preheating the slurry in the pressurized acid leaching process of laterite nickel ore specifically includes the following steps:

[0045] Step 1: Prepare a high-concentration slurry:

[0046] The 10% slurry produced from the laterite nickel ore beneficiation section is passed through a thickener 1 with a high pool wall (4-8m) (the cone angle of the thickener 1 is between 20° and 30°) to bring the concentration of the underflow slurry to 40-45%. The slurry with a concentration of 40-45% is then pumped to a high-pressure acid leaching feed tank 2 for buffering, and the overflow is returned to the beneficiation process return water tank.

[0047] Step 2, heating the slurry

[0048] The exhaust steam (temperature 105℃, pressure 15kPa(g)) from the low-temperature preheater 4 is entirely fed into the slurry of the high-pressure acid leaching feed tank 2 through the first exhaust steam pipe 5; the exhaust steam from the medium-temperature preheater 7 is sent to the high-pressure acid leaching feed tank 2 after being depressurized by the first pressure reducing valve 80102 on the first exhaust steam branch pipe 801 through the second exhaust steam pipe 802; an electric regulating valve 80202 is installed on the second exhaust steam branch pipe 802, which is electrically connected to the temperature transmitter 14 to monitor the temperature in the high-pressure acid leaching feed tank 2. When the slurry temperature in the high-pressure acid leaching feed tank 2 meets the requirements, the electric regulating valve 80202 is opened, and a portion of the exhaust steam from the medium-temperature preheater 7 is discharged to the tail gas scrubbing area through the second exhaust steam pipe 8 and the second exhaust steam branch pipe 802. The exhaust steam from the low-temperature preheater 4 and the exhaust steam from the medium-temperature preheater 7 heat the slurry in the high-pressure acid leaching feed tank 2 to 40-80°C, and then pump it into the low-temperature preheater 4 to complete the subsequent operations.

Claims

1. A device for preheating of the slurry in the high-pressure acid leaching process of laterite nickel ores, characterized by, Includes a thickener (1), which is connected to a high-pressure acid leaching feed tank (2). The lower side wall of the high-pressure acid leaching feed tank (2) is connected to the upper side wall of a low-temperature preheater (4) through a first slurry pipe (3). The top of the low-temperature preheater (4) is connected to the top of the high-pressure acid leaching feed tank (2) through a first exhaust pipe (5). The bottom of the low-temperature preheater (4) is connected to the upper side wall of the medium-temperature preheater (7) through the second slurry pipe (6). The top of the medium-temperature preheater (7) is connected to one end of the second exhaust pipe (8). The other end of the second exhaust pipe (8) is divided into a first exhaust branch pipe (801) and a second exhaust branch pipe (802). The first exhaust branch pipe (801) leads to the high-pressure acid leaching feed tank (2), and the second exhaust branch pipe (802) leads to the tail gas scrubbing area.

2. The apparatus for preheating slurry in the high-pressure acid leaching process of laterite nickel ore as described in claim 1, characterized in that, The height of the pool wall of the thickener (1) is between 4 and 8 m, and the cone angle of the thickener (1) is between 20° and 30°.

3. The apparatus for preheating slurry in the high-pressure acid leaching process of laterite nickel ore as described in claim 1, characterized in that, The bottom of the medium-temperature preheater (7) is connected to the upper side wall of the high-temperature preheater (10) through the third slurry pipe (9), the bottom of the high-temperature preheater (10) is connected to the high pressure vessel (12) through the high-temperature preheating pipe (11), and the top of the high-temperature preheater (10) is connected to the tail gas scrubbing area through the third exhaust pipe (13).

4. The apparatus for preheating slurry in the high-pressure acid leaching process of laterite nickel ore as described in claim 1, characterized in that, The first exhaust steam branch pipe (801) is provided with a first gate valve (80101) and a first pressure reducing valve (80102) in sequence. The first gate valve (80101) is located on the side close to the second exhaust steam pipe (8). The second exhaust pipe (802) is provided with a second gate valve (80201), an electric regulating valve (80202), a third gate valve (80203) and a fourth gate valve (80204) in sequence. The second gate valve (80201), the electric regulating valve (80202) and the third gate valve (80203) are connected in series, and the second gate valve (80201), the electric regulating valve (80202) and the third gate valve (80203) are connected in parallel with the fourth gate valve (80204). The second gate valve (80201) is located on the other side near the second exhaust pipe (8).

5. The apparatus for preheating slurry in the high-pressure acid leaching process of laterite nickel ore as described in claim 4, characterized in that, The electric regulating valve (80202) is electrically connected to the temperature transmitter (14).

6. The apparatus for preheating slurry in the high-pressure acid leaching process of laterite nickel ore as described in claim 1 or 3, characterized in that, Low-pressure flash steam is introduced into the low-temperature preheater (4), medium-pressure flash steam is introduced into the medium-temperature preheater (7), and high-pressure flash steam is introduced into the high-temperature preheater (10).

7. The apparatus for preheating slurry in the high-pressure acid leaching process of laterite nickel ore as described in claim 1 or 3, characterized in that, The first slurry pipe (3) is equipped with a slurry pump (15), the second slurry pipe (6) is equipped with two slurry pumps (15) in sequence, and the third slurry pipe (9) is equipped with three slurry pumps (15) in sequence.

8. The apparatus for preheating slurry in the high-pressure acid leaching process of laterite nickel ore as described in claim 3, characterized in that, A high-temperature diaphragm pump (16) is installed on the high-temperature preheating pipeline (11).

9. The apparatus for preheating slurry in the high-pressure acid leaching process of laterite nickel ore as described in claim 1, characterized in that, A pressure detection valve (17) is installed on the second exhaust pipe (8).

10. The apparatus for preheating slurry in the high-pressure acid leaching process of laterite nickel ore as described in claim 1, characterized in that, The thickener (1) is connected to the high-pressure acid leaching feed tank (2) through the feed pipe (18), and a slurry pump (15) is also installed on the feed pipe (18).

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