WO2025000329A1 - Multi-stage descaling system and method in high-pressure leaching process of laterite nickel ore - Google Patents

Abstract

A multi-stage descaling system and method in a high-pressure leaching process of laterite nickel ore. The multi-stage descaling system comprises a reaction kettle (1), a first scale inhibiting mechanism (104), and a second scale inhibiting mechanism (105); the first scale inhibiting mechanism (104) is communicated with an acid adding end (102) of the reaction kettle (1) and is used for adding a first scale inhibitor; and the second scale inhibiting mechanism (105) is communicated with a material discharging end (106) of the reaction kettle (1) and is used for adding a second scale inhibitor. The multi-stage descaling method comprises: injecting ore pulp, steam, and H₂SO₄ into the reaction kettle (1); regulating the internal temperature and the internal pressure; and respectively adding the first scale inhibitor and the second scale inhibitor at the acid adding end (102) and the material discharging end (106) of the reaction kettle (1). By providing the first scale inhibiting mechanism (104) and the second scale inhibiting mechanism (105), the first scale inhibitor and the second scale inhibitor of different types are respectively added at the acid adding end (102) and the material discharging end (106) of the reaction kettle (1), so that the scaling of different types of substances can be inhibited, thereby achieving a more targeted scale inhibiting effect.

Description

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

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

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.

However, during the high-temperature leaching process, due to the hydrolysis and precipitation of Fe ³⁺ and Al ³⁺ metal ions, the precipitation of low-solubility substances such as CaSO ₄ , and the precipitation of solid impurities such as SiO ₂ in the mineral, scale will form on the wall of the high-pressure reactor, the blade surface of the stirring paddle, the inner wall of the reactor discharge pipe, and the valve, 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 stop will reduce production efficiency and cause fluctuations in production process indicators. Patent CN115011813B discloses a scale inhibitor composed of polyphosphate, perfluoroalkyl carboxylate and alkyl glycoside, but the scale inhibitor contains phosphorus and fluorine, and its discharge without treatment will cause serious pollution to water bodies and the environment; Patent CN1831160A discloses a scale inhibition method using magnetic field, surfactant and microwave radiation, but its operation is relatively complicated and Cu2 ⁺ is added in the process, which brings additional separation and purification costs in the subsequent nickel-cobalt product production process.

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

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.

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:

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

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

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

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.

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.

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.

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.

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

Inject slurry, steam and H ₂ SO ₄ into the reactor;

Regulate internal temperature and pressure;

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.

Furthermore, the following steps are 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.

Furthermore, the first scale inhibitor is used to inhibit scaling of Fe ₂ O ₃ and H ₃ OAl ₃ (SO ₄ ) ₂ (OH) ₆ .

Furthermore, the second scale inhibitor is used to inhibit CaSO ₄ and SiO ₂ scale.

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.

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.

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

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.

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 into 40-50° C. deionized water and stirred until completely dissolved, and then injected into the reactor at a speed of 0.5 m ³ /h.

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

Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a first scale inhibitor The first scale inhibitor and the second scale inhibitor are respectively added at the acid adding end and the discharging end of the reactor to 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 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 the scale inhibitor is low, and the cost is low.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 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;

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;

2. Electromagnetic anti-scaling mechanism; 21. Controller; 22. Coil; 201. Discharge pipe.

DETAILED DESCRIPTION

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.

As shown in FIG1 , the present invention provides a multi-stage descaling system in a high-pressure leaching process of laterite nickel ore, comprising a reactor 1, a first descaling mechanism 104 and a second descaling mechanism 105. One end of the reactor 1 is an acid adding end 102, and the other end is a discharge end 103. A feed end 106 is provided on the side close to the acid adding end 102 for feeding. The first descaling mechanism 104 is connected to the acid adding end 102 and is used to add a first descaling agent to prevent the precipitation and scaling caused by local over-acidification. The second descaling mechanism 105 is connected to the discharge end 103 and is used to add a second descaling agent to prevent the precipitation and scaling caused by local over-acidification. Precipitation and scaling caused by speed change.

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.

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.

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 .

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.

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.

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.

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.

Preferably, the number of the compartments 101 is five, and the first scale inhibition mechanism 104 and the second The above-mentioned compartments 101 are connected, and the discharge end 103 and the second scale inhibition mechanism 105 are both connected to the fifth compartment 101.

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.

Table 1 Scaling of compartments without anti-scaling measures

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 due to local overheating and local overacidification, excessive leaching of Fe3 ⁺ and Al3 ⁺ will occur, and then a large amount of hydrolysis will produce precipitation; the fifth compartment 101 is close to the discharge pipe 201, the flow rate is slow, and the particles are easy to deposit, 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 overacid near the acid addition end 102 causes precipitation to aggregate, and the discharge pipe 201 The flow rate is reduced, resulting in Precipitation and aggregation, therefore, adding scale inhibitors at two locations separately can achieve a multi-stage descaling effect and be targeted.

In use, the compartment 101 corresponding to the acid addition end 102 is provided with a first scale inhibition mechanism 104 for adding a first scale inhibitor for inhibiting the scaling of Fe ₂ O ₃ and H ₃ OAl ₃ (SO ₄ ) ₂ (OH) ₆ , which has a stronger scale inhibition effect on Fe ₂ O ₃ and H ₃ OAl ₃ (SO ₄ ) ₂ (OH) ₆ ; and the compartment 101 corresponding to the discharge end 103 is provided with a second scale inhibition mechanism 105 for adding a second scale inhibitor for inhibiting the scaling of CaSO ₄ and SiO ₂ , which has a stronger scale inhibition effect on CaSO ₄ and SiO _2. 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 of the reactor 1 and the discharge end 103 during the high-pressure leaching of laterite nickel ore, a multi-stage scale inhibition method can improve the efficiency of scale inhibition and effectively reduce the amount of scale inhibitor used and the operating cost of the scale inhibition process.

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.

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.

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

Inject slurry, steam and H ₂ SO ₄ into the reactor 1;

Regulate internal temperature and pressure;

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.

Furthermore, the following steps are included:

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

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 .

Furthermore, in order to perform targeted scale inhibition on the acid addition end 102, the first scale _inhibitor is used to inhibit scaling _{of Fe2O3} and _H3OA13 ( _SO4 ) ₂ (OH) ₆ .

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 .

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.

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 terpolymers thereof, without containing phosphorus and fluorine, and without adding Cu ²⁺ , thereby effectively controlling the post-processing cost of overall scale inhibition.

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.

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.

Furthermore, the first scale inhibitor or the second scale inhibitor is used after preparation, and the raw material of the first scale inhibitor or the second scale inhibitor is added to deionized water at 40-50°C and stirred until completely dissolved, and then injected into the reactor 1 at a rate of ^0.5m3 /h to maintain a continuous scale inhibition effect, wherein the mass concentration of the solution of the first scale inhibitor or the second scale inhibitor is 0.1-1wt%.

In a certain embodiment, a high-pressure leaching experiment of laterite nickel ore was conducted for 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. The high-pressure acid leaching experiment process of laterite nickel ore: the slurry flow rate is ^45m3 /h, the slurry solid content is 38%, the acid-ore ratio is 0.34, the pressure is 4.5MPa, the reaction temperature is 250℃, and the reaction slurry residence time is 60min. After running for one month according to this process parameter, the machine was shut down to clean the slurry, and the scaling materials on the inner wall of the compartment 101 of the reactor 1 and the inner wall of the discharge pipe 201 were knocked off with a hammer, and the thickness of the scale layer was measured with a vernier caliper. The comparison results are shown in the following table.

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

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.

The present invention provides a first scale inhibition mechanism and a second scale inhibition mechanism, adds a first scale inhibitor for _Fe2O3 and _H3OA13 ( _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, thereby obtaining a more targeted scale inhibition effect through multi-stage descaling, and simultaneously exerting 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 water molecules in the discharge pipe resonate and 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, thereby extending the operation cycle of the high-pressure acid leaching system of laterite nickel ore and reducing the scale caused by scale removal. The purpose of stopping production and reducing production is achieved; it has good anti-scaling effect, is safe and environmentally friendly, and is simple to operate, easy to use, has low usage of anti-scaling agents, and has low cost.

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 (15)

A multi-stage descaling system in a high-pressure leaching process of laterite nickel ore, characterized in that it comprises: A reactor, one end of which is an acid adding end and the other end is a material discharging end; A first scale inhibitor, which is connected to the acid adding end and is used to add a first scale inhibitor; and The second scale inhibition mechanism is communicated with the discharge end and is used for adding a second scale inhibitor. The multi-stage descaling system in the high-pressure leaching process of laterite nickel ore according to claim 1 is characterized in that 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. The multi-stage descaling system in the high-pressure leaching process of laterite nickel ore according to claim 2, characterized in that the first scale inhibitor and the second scale inhibitor are of different types and are respectively used to inhibit scaling of different types of substances. The multi-stage descaling system in the high-pressure leaching process of laterite nickel ore according to claim 1 is characterized in that a plurality of partitions are arranged in sequence 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. The multi-stage descaling system in the high-pressure leaching process of laterite nickel ore according to claim 4 is characterized in that there are five compartments, the first scale inhibition mechanism is connected to the second compartment, and the discharge end and the second scale inhibition mechanism are both connected to the fifth compartment. A multi-stage descaling method in a high-pressure leaching process of laterite nickel ore, characterized in that it comprises the following steps: Inject slurry, steam and H ₂ SO ₄ into the reactor; Regulate internal temperature and pressure; 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. The multi-stage descaling method according to claim 6, characterized in that it also includes the following step, 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. The multi-stage descaling method according to claim 7, characterized in that the first scale inhibitor is used to inhibit scaling of Fe ₂ O ₃ and H ₃ OAl ₃ (SO ₄ ) ₂ (OH) ₆ . The multi-stage descaling method according to claim 8, characterized in that the second scale inhibitor is used to inhibit _CaSO4 and _SiO2 scale. The multi-stage descaling method according to claim 9 is 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. The multi-stage descaling method according to claim 10 is 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 their corresponding copolymers or terpolymers. The multi-stage descaling method according to claim 11 is characterized in that the mass concentration of the first scale inhibitor and the second scale inhibitor in the slurry is 10-50 mg/L. The multi-stage descaling method according to claim 12 is 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. The multi-stage descaling method according to claim 13 is characterized in that the first scale inhibitor or the second scale inhibitor is used after preparation, and 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 injected into the reactor at a speed of ^0.5m3 /h. The multi-stage descaling method according to claim 14 is characterized in that the solution mass concentration of the first scale inhibitor or the second scale inhibitor is 0.1-1wt%.