Multi-stage descaling system and multi-stage descaling method in high-pressure leaching process of laterite nickel ore

Abstract

The technical solution of the present invention provides a multi-stage descaling system and a multi-stage descaling method in the high-pressure leaching process of laterite nickel ore. The multi-stage descaling system includes a reactor, a first scale inhibition mechanism and a second scale inhibition mechanism. The first scale inhibition mechanism is connected to the acid addition end of the reactor and is used to add a first scale inhibitor. The second scale inhibition mechanism is connected to the discharge end of the reactor and is used to add a second scale inhibitor. The multi-stage descaling method includes injecting slurry, steam and H2SO4 into the reactor, regulating the internal temperature and internal pressure, and adding the first scale inhibitor and the second scale inhibitor to the acid addition end and the discharge end of the reactor, respectively. The present invention provides a first scale inhibition mechanism and a second scale inhibition mechanism to respectively add different types of first scale inhibitors and second scale inhibitors to the acid addition end and the discharge end of the reactor, which can respectively inhibit the scaling of different types of substances and obtain a more targeted scale inhibition effect.

Description

Technical Field

[0001] The invention relates to the technical field of high-pressure leaching of laterite nickel ore, and in particular to a multi-stage descaling system and a multi-stage descaling method in the high-pressure leaching process of laterite nickel ore. Background Art

[0002] With the vigorous development of my country's new energy vehicle industry and the gradual depletion of high-quality nickel and cobalt resources in my country, the industry's demand for Ni, Co, and Mn metals in new energy ternary materials is increasing, and the development of laterite nickel ores with large reserves but low nickel grade has gradually become a hot spot in the industry. The hydrometallurgical route of sulfuric acid leaching under high temperature and high pressure conditions is currently one of the mainstream smelting processes for laterite nickel ores.

[0003] However, during the high temperature leaching process, due to the Fe 3+ and Al 3+ The hydrolysis and precipitation of metal ions, the precipitation of low-solubility substances such as CaSO4, and the precipitation of solid impurities such as SiO2 in minerals will form scale on the walls of the high-pressure reactor, the blades of the agitator, the inner wall of the reactor discharge pipe, and the valves, causing a series of problems that are not conducive to production, such as blockage of the discharge pipe and valve, increased pressure drop, and reduced reactor volume. At present, the main method to deal with scaling in actual production is to stop the machine regularly for scale removal, but frequent start-up and shutdown will reduce production efficiency and cause fluctuations in production process indicators. Patent CN115011813B discloses a scale inhibitor composed of a polyphosphate, a perfluoroalkyl carboxylate, and an alkyl glycoside, but the scale inhibitor used contains phosphorus and fluorine, and untreated discharge will cause serious pollution to water bodies and the environment; Patent CN1831160A discloses a scale inhibition method using magnetic fields, surfactants, and microwave radiation, but its operation is relatively complicated and Cu is added during the process. 2+ , which brings additional separation and purification costs in the subsequent nickel-cobalt product production process.

[0004] Therefore, in the high-pressure leaching process of laterite nickel ore, how to effectively reduce the scaling rate of the reactor is of great significance to prolonging the production time and improving the production efficiency. Summary of the invention

[0005] In view of this, it is necessary to provide a multi-stage descaling system in the high-pressure leaching process of laterite nickel ore to solve the technical problem of how to effectively reduce the scaling rate of the reactor in the high-pressure leaching process of laterite nickel ore in the prior art.

[0006] In order to achieve the above technical objectives, the technical solution of the present invention provides a multi-stage descaling system in the high-pressure leaching process of laterite nickel ore, comprising:

[0007] A reactor, one end of which is an acid adding end and the other end is a material discharging end;

[0008] A first scale inhibitor, which is connected to the acid adding end and is used to add a first scale inhibitor; and

[0009] The second scale inhibition mechanism is communicated with the discharge end and is used for adding a second scale inhibitor.

[0010] Furthermore, the multi-stage descaling system also includes an electromagnetic scale inhibition mechanism, the discharge end is provided with a discharge pipe, and the electromagnetic coil of the electromagnetic scale inhibition mechanism is sleeved on the discharge pipe and is used to generate an oscillating magnetic field in the discharge pipe.

[0011] Furthermore, the first scale inhibitor and the second scale inhibitor are of different types and are used to inhibit scaling of different types of substances, respectively.

[0012] Furthermore, a plurality of partitions are sequentially arranged in the reactor along the material flow direction, and the plurality of partitions divide the cavity in the reactor into a plurality of compartments, each of the compartments is provided with a stirring device, and the upper parts of any two adjacent compartments are connected.

[0013] Furthermore, there are five compartments, the first scale inhibition mechanism is communicated with the second compartment, and the discharge end and the second scale inhibition mechanism are both communicated with the fifth compartment.

[0014] The present invention also provides a multi-stage descaling method in a high-pressure leaching process of laterite nickel ore, comprising the following steps:

[0015] Inject slurry, steam and H2SO4 into the reactor;

[0016] Regulate internal temperature and pressure;

[0017] The first scale inhibitor and the second scale inhibitor are added to the acid adding end and the material discharging end of the reactor respectively.

[0018] Furthermore, the following steps are included:

[0019] A discharge pipe is arranged at the discharge end and electromagnetic descaling is performed on the discharge pipe;

[0020] Among them, electromagnetic descaling is carried out regularly, once a week or two weeks, and each time it runs for several hours.

[0021] Furthermore, the first scale inhibitor is used to inhibit scaling of Fe2O3 and H3OAl3(SO4)2(OH)6.

[0022] Furthermore, the second scale inhibitor is used to inhibit the scaling of CaSO4 and SiO2.

[0023] Furthermore, the first scale inhibitor is an anionic surfactant, including one or more of sodium alkylbenzene sulfonate, sodium alkyl sulfate, sodium carboxymethyl cellulose sulfonate, sodium hydroxyethyl cellulose sulfonate or sodium lignin sulfonate.

[0024] Furthermore, the second scale inhibitor is a dispersed corrosion inhibitor, including one or more of polyacrylic acid, polyaspartic acid, polyepoxysuccinic acid, hydrolyzed polymaleic anhydride and corresponding copolymers or terpolymers thereof.

[0025] Furthermore, the mass concentration of the first scale inhibitor and the second scale inhibitor in the slurry is 10-50 mg / L.

[0026] Furthermore, the solid content of the slurry in the reactor is 20-40wt%, the acid-ore mass ratio is 0.2-0.4, the pressure is 3-4.5Mpa, the reaction temperature is 230-270°C, and the residence time of the slurry in the reactor 1 is 50-90min.

[0027] Furthermore, the first scale inhibitor or the second scale inhibitor is used after preparation, the raw material of the first scale inhibitor or the second scale inhibitor is added to 40-50° C. deionized water and stirred until completely dissolved, and then 0.5 m 3 / h is injected into the reactor.

[0028] Furthermore, the solution mass concentration of the first scale inhibitor or the second scale inhibitor is 0.1-1 wt %.

[0029] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a first scale inhibition mechanism and a second scale inhibition mechanism to respectively add different types of first scale inhibitors and second scale inhibitors at the acid adding end and the discharging end of the reactor, which can respectively inhibit the scaling of different types of substances, thereby obtaining a more targeted scale inhibition effect, and effectively reducing the amount of scaling on the inner wall of the reactor during high-pressure acid leaching of laterite nickel ore, thereby achieving the purpose of extending the operation cycle of the high-pressure acid leaching system of laterite nickel ore and reducing shutdown and production reduction caused by scale cleaning; and the present invention has good scale inhibition effect, is safe and environmentally friendly, and is simple to operate, easy to use, has a low amount of scale inhibitors, and has a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 2 is a schematic structural diagram of a multi-stage descaling system in a high-pressure leaching process of laterite nickel ore according to an embodiment of the present invention;

[0031] In the figure: 1, reactor; 101, compartment; 102, acid adding end; 103, discharge end; 104, first scale inhibition mechanism; 105, second scale inhibition mechanism; 106, feed end;

[0032] 2. Electromagnetic anti-scaling mechanism; 21. Controller; 22. Coil; 201. Discharge pipe. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0034] like Figure 1 As shown, the present invention provides a multi-stage descaling system in the high-pressure leaching process of laterite nickel ore, comprising a reactor 1, a first scale-inhibiting mechanism 104 and a second scale-inhibiting mechanism 105, wherein one end of the reactor 1 is an acid-adding end 102, and the other end is a discharge end 103, and a feeding end 106 is provided on a side close to the acid-adding end 102 for feeding. The first scale-inhibiting mechanism 104 is connected to the acid-adding end 102 and is used to add a first scale inhibitor for the precipitation and scaling caused by local over-acidification. The second scale-inhibiting mechanism 105 is connected to the discharge end 103 and is used to add a second scale inhibitor for the precipitation and scaling caused by the change of the discharge flow rate.

[0035] It can be understood that the first scale inhibitor is added at the acid adding end 102 and the second scale inhibitor is added at the discharge end 103 respectively. The two scale inhibitors can also produce a synergistic effect to enhance the scale inhibition effect.

[0036] The first scale inhibitor and the second scale inhibitor are of different types and are used to inhibit scaling of different types of substances respectively.

[0037] In this embodiment, the multi-stage descaling system further includes an electromagnetic scale inhibition mechanism 2 , the discharge end 103 is provided with a discharge pipe 201 , the electromagnetic coil 22 of the electromagnetic scale inhibition mechanism 2 is sleeved on the discharge pipe 201 and is used to generate an oscillating magnetic field in the discharge pipe 201 .

[0038] Among them, the electromagnetic scale inhibition mechanism 2 outputs a pulse current through the controller 21, and transmits it to the coil 22 spirally wound on the discharge pipe 201 to induce an oscillating magnetic field, causing the water molecules in the discharge pipe 201 to resonate, and the magnetic field sweeps through the water flow at a pre-designed frequency to remove scale on the pipe wall.

[0039] It can be understood that the electromagnetic scale inhibition mechanism 2 can be an existing mature electromagnetic pulse device, which can generate an oscillating magnetic field by spirally winding the external coil 22 at the discharge end 103, so as to effectively inhibit scale by oscillation, and is easy to operate.

[0040] Furthermore, a plurality of partitions are sequentially arranged in the reactor 1 along the material flow direction, and the plurality of partitions divide the cavity in the reactor 1 into a plurality of compartments 101. A stirring device is provided in each compartment 101, and any two adjacent compartments 101 are connected at the top. The upper connection position is the gap formed between the partition and the reactor 1, and overflow is carried out through the gap to form circulation.

[0041] It can be understood that each compartment 101 has a separate stirring device, which is vertically installed above the kettle body. Under high temperature and high pressure conditions, the slurry undergoes a series of chemical reactions with acid, steam, etc. under stirring to achieve the purpose of nickel leaching.

[0042] Preferably, there are five compartments 101 , the first scale inhibition mechanism 104 is communicated with the second compartment 101 , and the discharge end 103 and the second scale inhibition mechanism 105 are both communicated with the fifth compartment 101 .

[0043] Specifically, when no anti-scaling measures are taken in the reactor 1, the scale thickness of the inner wall at different positions and the main costs are analyzed, as shown in the following table.

[0044] Table 1 Scaling of compartments without anti-scaling measures

[0045]

[0046] It can be understood that the scaling in the reactor 1 is mainly concentrated in the second and fifth compartments 101 of the reactor 1. The second compartment 101 is close to the acid addition end 102, so local overheating and local overacidification will cause Fe 3+ and Al 3 + The excessive leaching of the wastewater leads to a large amount of hydrolysis and precipitation; the fifth compartment 101 is close to the discharge pipe 201, the flow rate is slow, and the particles are easily deposited, so the scaling is serious. Compared with the reactor 1, since the volume of the discharge pipe 201 is smaller, the thickness of the scaling layer is significantly increased, and the content of CaSO4 and SiO2 in the scaling is significantly increased. Specifically, the excessive acid near the acid addition end 102 causes the precipitation to aggregate, and the flow rate out of the discharge pipe 201 is reduced, resulting in the aggregation of precipitation. Therefore, adding scale inhibitors at two locations can achieve a multi-stage descaling effect and be targeted.

[0047] In use, the compartment 101 corresponding to the acid addition end 102 is provided with a first scale inhibition mechanism 104, which is used to add a first scale inhibitor that inhibits the scaling of Fe2O3 and H3OAl3(SO4)2(OH)6, and has a stronger scale inhibition effect on Fe2O3 and H3OAl3(SO4)2(OH)6; and the compartment 101 corresponding to the discharge end 103 is provided with a second scale inhibition mechanism 105, which is used to add a second scale inhibitor that inhibits the scaling of CaSO4 and SiO2, and has a stronger scale inhibition effect on CaSO4 and SiO2. When the two scale inhibitors are added, the synergistic promotion effect of the first scale inhibitor and the second scale inhibitor is exerted. By carrying out targeted scale inhibition according to the scaling conditions in different compartments 101 and the discharge end 103 of the reactor 1 during the high-pressure leaching of laterite nickel ore, the multi-stage scale inhibition method can improve the efficiency of scale inhibition, and effectively reduce the amount of scale inhibitors and operating costs in the scale inhibition process.

[0048] The first anti-scaling mechanism 104 and the second anti-scaling mechanism 105 feed the anti-scaling agent solution into the reactor 1 from the connection point of the reactor 1 through the feeding pump.

[0049] It should be noted that the combination of the two scale inhibitors will further reduce the surface tension of the slurry solution. This is mainly due to the differences in the head groups and chain structures of the two different scale inhibitors, and the free energy of the formed mixture is lower. This reduction effect is better than increasing the concentration of a single scale inhibitor, making it less likely for the precipitate contained in the slurry to adhere to the wall when in contact with the wall.

[0050] The present invention also provides a multi-stage descaling method, comprising the following steps:

[0051] Inject slurry, steam and H2SO4 into the reactor 1;

[0052] Regulate internal temperature and pressure;

[0053] The first scale inhibitor and the second scale inhibitor are added to the acid adding end 102 and the material discharging end 103 of the reactor 1 respectively to carry out targeted scale inhibition.

[0054] Furthermore, the following steps are included:

[0055] A discharge pipe 201 is provided at the discharge end 103 and electromagnetic descaling is performed on the discharge pipe 201;

[0056] The electromagnetic descaling is performed regularly, once a week or two weeks, and a single operation lasts for several hours, so as to actively descalate the discharge pipe 201 at the discharge end 103 .

[0057] Furthermore, in order to carry out targeted scale inhibition on the acid addition end 102, the first scale inhibitor is used to inhibit scaling of Fe2O3 and H3OAl3(SO4)2(OH)6.

[0058] Furthermore, in order to carry out targeted scale inhibition on the discharge end 103, the second scale inhibitor is used to inhibit the scale of CaSO4 and SiO2.

[0059] Furthermore, in order to ensure that the scale inhibitor used can inhibit scale and be safe and environmentally friendly, the first scale inhibitor is an anionic surfactant, including one or more of sodium alkylbenzene sulfonate, sodium alkyl sulfate, sodium carboxymethyl cellulose sulfonate or sodium hydroxyethyl cellulose sulfonate or sodium lignin sulfonate, and does not contain phosphorus and fluorine, thereby reducing the pollution of emissions to water bodies and the environment.

[0060] Furthermore, the second scale inhibitor is a dispersed corrosion inhibitor at the discharge end 103, including one or more of polyacrylic acid, polyaspartic acid, polyepoxysuccinic acid, hydrolyzed polymaleic anhydride and corresponding copolymers or trimers thereof, without containing phosphorus and fluorine, and without adding Cu 2+ , effectively controlling the post-processing cost of overall scale inhibition.

[0061] Furthermore, in order to ensure the quality of scale inhibition, the mass concentration of the first scale inhibitor and the second scale inhibitor in the slurry is 10-50 mg / L, so that the first scale inhibitor and the second scale inhibitor have sufficient mass concentration.

[0062] Furthermore, the solid content of the slurry in the reactor 1 is 20-40wt%, the acid-ore mass ratio is 0.2-0.4, the pressure is 3-4.5Mpa, the reaction temperature is 230-270°C, and the residence time of the slurry in the reactor 1 is 50-90min.

[0063] Furthermore, the first scale inhibitor or the second scale inhibitor is used after preparation, the raw material of the first scale inhibitor or the second scale inhibitor is added to 40-50° C. deionized water and stirred until completely dissolved, and then 0.5 m 3 / h is injected into the reactor 1 to maintain a continuous anti-scaling effect, wherein the mass concentration of the first anti-scaling agent or the second anti-scaling agent solution is 0.1-1wt%.

[0064] In one embodiment, a high-pressure leaching experiment of laterite nickel ore was conducted to investigate the scale inhibition effect of the scale inhibitor, and the scaling conditions of the multi-stage scale inhibition device and the non-multi-stage scale inhibition system were compared. 3 / h, slurry solid content of 38%, acid-ore ratio of 0.34, pressure of 4.5MPa, reaction temperature of 250℃, reaction slurry residence time of 60min. After running for one month according to this process parameter, the machine was shut down to clean the slurry, and the scaling material on the inner wall of the compartment 101 of the reactor 1 and the inner wall of the discharge pipe 201 was knocked off with a hammer, and the thickness of the scaling layer was measured with a vernier caliper. The comparison results are shown in the following table.

[0065] Table 2 Comparison of scale thickness before and after adding scale inhibitor in this example

[0066]

[0067] From the experimental results shown in Table 2, it can be seen that the multi-stage scale inhibition system has an obvious effect of targeted inhibition of key locations where scaling is serious in reactor 1, effectively preventing the problem of excessive local scaling during the high-pressure acid leaching process, extending the operating time of the high-pressure acid leaching device, and reducing production losses caused by shutdown for scale removal.

[0068] The present invention provides a first scale inhibition mechanism and a second scale inhibition mechanism, adds a first scale inhibitor for Fe2O3 and H3OAl3(SO4)2(OH)6 in a compartment near the acid adding end, and adds a second scale inhibitor for CaSO4 and SiO2 in a compartment near the discharging end, so as to obtain a more targeted scale inhibition effect through multi-stage descaling, and simultaneously exert the synergistic promotion effect of the first scale inhibitor and the second scale inhibitor; at the same time, an electromagnetic scale inhibition mechanism is added to the discharge pipe at the subsequent discharge end, and an oscillating magnetic field is induced by a coil. The magnetic field sweeps through the water flow at a pre-designed frequency, so that the water molecules in the discharge pipe resonate and the scale on the pipe wall is removed; the scaling amount on the inner wall of the reactor and the discharge pipe during high-pressure acid leaching of laterite nickel ore is effectively reduced, so as to achieve the purpose of extending the operation cycle of the high-pressure acid leaching system of laterite nickel ore and reducing the shutdown and production reduction caused by scale cleaning; and the scale inhibition effect is good, safe and environmentally friendly, and the operation is simple, the use is convenient, the dosage of scale inhibitor is low, and the cost is low.

[0069] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A multi-stage descaling method in the high-pressure leaching process of laterite nickel ore, characterized in that: The following steps are involved: Inject slurry, steam and H2SO4 into the reactor; Regulate internal temperature and pressure; and adding the first scale inhibitor and the second scale inhibitor to the acid adding end and the material discharging end of the reaction kettle respectively; The first scale inhibitor is used to inhibit scaling of Fe2O3 and H3OAl3(SO4)2(OH)6; The second scale inhibitor is used to inhibit CaSO4 and SiO2 scale.

2. The multi-stage descaling method according to claim 1, characterized in that: The following steps are also included: A discharge pipe is arranged at the discharge end and electromagnetic descaling is performed on the discharge pipe; Among them, electromagnetic descaling is carried out regularly, once a week or two weeks, and each time it runs for several hours.

3. The multi-stage descaling method according to claim 2, characterized in that: The first scale inhibitor is an anionic surfactant, including one or more of sodium alkylbenzene sulfonate, sodium alkyl sulfate, sodium carboxymethyl cellulose sulfonate, sodium hydroxyethyl cellulose sulfonate or sodium lignin sulfonate.

4. The multi-stage descaling method according to claim 3, characterized in that: The second scale inhibitor is a dispersed corrosion inhibitor, including one or more of polyacrylic acid, polyaspartic acid, polyepoxysuccinic acid, hydrolyzed polymaleic anhydride and corresponding copolymers or terpolymers thereof.

5. The multi-stage descaling method according to claim 4, characterized in that: The mass concentration of the first scale inhibitor and the second scale inhibitor in the ore slurry is 10-50 mg / L.

6. The multi-stage descaling method according to claim 5, characterized in that: The solid content of the slurry in the reactor is 20-40wt%, the acid-ore mass ratio is 0.2-0.4, the pressure is 3-4.5Mpa, the reaction temperature is 230-270°C, and the residence time of the slurry in the reactor is 50-90min.

7. The multi-stage descaling method according to claim 6, characterized in that: The first scale inhibitor or the second scale inhibitor is used after preparation. The raw material of the first scale inhibitor or the second scale inhibitor is added to 40-50° C. deionized water and stirred until completely dissolved. Then, 0.5 m 3 / h is injected into the reactor.

8. The multi-stage descaling method according to claim 7, characterized in that: The solution mass concentration of the first scale inhibitor or the second scale inhibitor is 0.1-1 wt %.

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