A method for efficiently treating laterite nickel ore high-pressure acid leaching residue

Abstract

This invention discloses a method for efficiently treating laterite nickel ore high-pressure acid leaching residue. Based on the characteristics of a belt roasting process with burners and regenerative airflow in a top-down heating mode, where the upper layer temperature is high and the lower layer temperature is low, the method proposes distributing green pellets made from slag pellets alone in the upper layer, while distributing green pellets with a core-shell structure, which are grown from the slag alone, in the lower layer. This method achieves efficient and stable sulfur removal from slag pellets at high material layer thicknesses. Compared to single slag pelletizing and distribution techniques, the material layer thickness can be increased by up to 100 mm, and productivity can be increased by up to 22%, thus reducing slag treatment process costs.

Description

Technical Field

[0001] The invention relates to a method for efficiently treating high-pressure acid leaching residues from laterite nickel ore, and belongs to the research field of metallurgy and industrial solid waste comprehensive utilization technology. Background Art

[0002] Nickel, a key industrial metal, is widely used in the production of materials such as stainless steel, nickel-based alloys, and ternary cathodes. Particularly now, technological advancements in the new energy sector and shifts in energy demand are driving rapid growth in this sector, leading to a corresponding surge in nickel market demand.

[0003] In recent years, with the increasing depletion of nickel sulfide ore resources, laterite nickel ore has gradually become the main source of nickel extraction. Generally speaking, the mining portion of laterite nickel ore is generally divided into three parts from top to bottom: limonite layer, clay layer, and saprolitic layer. The limonite layer with low nickel grade and low silicon and magnesium content is suitable for wet processing, accounting for 65% to 75%; the saprolitic layer with high nickel grade and low silicon and magnesium content is suitable for pyrolytic processing, accounting for 15% to 25%; the clay layer between the two accounts for about 10% and can be processed by either wet or pyrolytic methods. Among them, limonite-type laterite nickel ore with the largest metal reserves has attracted widespread attention. Among the corresponding wet processing processes, high-pressure leaching technology (HPAL) of laterite nickel ore has the advantages of low carbon emissions, low energy consumption, high comprehensive recovery rate of nickel and cobalt metals, and mature technology. It has now become the mainstream choice for wet smelting of low-grade limonite-type laterite nickel ore.

[0004] However, due to the influence of ore grade and smelting processes, every ton of nickel produced generates approximately 120 tons of high-pressure acid leaching (HPAL) slag, which is rich in iron and sulfur. Currently, HPAL slag is primarily stored directly, but the iron and sulfur components of the slag are not effectively utilized, resulting in significant resource waste. Furthermore, the leaching of harmful ions such as heavy metals and sulfate from the slag can pose significant safety risks to the local ecological environment. Therefore, the harmless and resource-efficient treatment of HPAL slag is urgently needed.

[0005] On the one hand, sulfur in laterite nickel ore high-pressure acid leaching residue primarily exists in the form of calcium sulfate, which has a high decomposition temperature. On the other hand, due to its small particle size, large specific surface area, and chemical composition, particles of laterite nickel ore high-pressure acid leaching residue are prone to melting at high temperatures. These combined limitations result in high slag desulfurization temperatures and a narrow window, making deep separation of iron and sulfur difficult. Belt-type pellet roasting is a mature and reliable process for preparing ironmaking raw materials. Its temperature is easily controlled and flue gas can be collected in stages, offering a potential way to separate iron and sulfur from laterite nickel ore high-pressure acid leaching residue and realize resource utilization. However, the belt roasting process utilizes burners and regenerated airflow from top to bottom. This often results in higher temperatures in the upper layer of the material, resulting in higher heat transfer efficiency and lower temperatures, while the lower layer of the material has less heat transfer efficiency and lower temperatures. When the material layer is too thick, the temperature difference between the upper and lower layers exceeds the desulfurization temperature window. Consequently, even if the upper layer temperature is at the upper limit of the desulfurization window, the lower layer temperature is insufficient to remove sulfur to the standard of <0.2%.

[0006] Therefore, developing a method for efficient treatment of high-pressure acid leaching residue of laterite nickel ore based on the belt roasting process is crucial to achieve deep separation of sulfur and iron elements and subsequent large-scale resource recovery and utilization. Summary of the Invention

[0007] In response to the defects and shortcomings of the prior art, the present invention aims to provide a method for efficiently treating high-pressure acid leaching residue from laterite nickel ore. This method, by rationally distributing core-shell structured pellets and ordinary pellets and combining the top-down heating mode of the belt roaster's reheated airflow, can achieve deep separation of iron and sulfur elements in pellets from high-pressure acid leaching residue from laterite nickel ore under conditions of high material layer thickness. Compared with single slag pelletizing and distribution technology, the material layer thickness can be increased by up to 100 mm, the productivity can be increased by up to 22%, and the slag treatment process cost can be significantly reduced.

[0008] In order to achieve the above technical objectives, the present invention provides a method for efficiently treating laterite nickel ore high-pressure acid leaching residue, the method comprising the following steps:

[0009] 1) Mix the high pressure acid leaching residue of laterite nickel ore with solid fuel and then pelletize it in disc pelletizer I 0 The pelletizing is carried out in the process to obtain green pellets Ⅰ 0 At the same time, the high pressure acid leaching residue of laterite nickel ore is pelletized separately in the disc pelletizer II to obtain green ball material II; the high pressure acid leaching residue of laterite nickel ore and the green ball material I are used to pelletize the green ball material II. 0 The pelletizing is continued in the disc pelletizer I to obtain green pellets I having a core-shell structure;

[0010] 2) Placing green pellets I on the grate plate of the belt roasting machine to form a distribution layer I, and then placing green pellets II on the distribution layer I to form a distribution layer II;

[0011] 3) The finished material layer enters the belt roasting machine for heat treatment to obtain iron-containing materials and sulfur dioxide flue gas.

[0012] The key to the technical solution of the present invention is that, based on the characteristics of the belt roasting process burner and the reheated airflow from top to bottom heating mode, the temperature of the upper material layer is high and the temperature of the lower material layer is low, the raw balls made by granulating the high-pressure acid leaching slag of laterite nickel ore separately are distributed in the upper material layer, and the high temperature generated by the external heat source of the raw balls is directly used to effectively remove the sulfur element in the slag of the upper material layer; the high-pressure acid leaching slag of laterite nickel ore is mixed with solid fuel and granulated, and then the raw balls with a core-shell structure grown by the slag separately are distributed in the lower material layer, realizing the internal and external dual heating mode of the small balls, effectively overcoming the shortcomings of the belt roasting process of less contact heat, low heat transfer efficiency and low temperature of the lower material layer, efficiently removing the sulfur element in the slag of the lower material layer, and realizing stable desulfurization of the entire material layer within the slag desulfurization temperature window. At the same time, by adding solid fuel to the lower core structure of the raw pellets, carbon is introduced, significantly reducing the decomposition temperature of the calcium sulfate-based sulfur phase, increasing the reaction rate. This, in turn, increases internal porosity, improves the kinetics of the sulfur removal reaction, and enables precise and rapid sulfur removal from the slag. Furthermore, the presence of the shell structure effectively prevents adhesion caused by the formation of low-melting-point compounds between high-pressure acid leaching residue from laterite nickel ore and the solid fuel pelletizing material, facilitating smooth process operation.

[0013] As a preferred solution, the moisture content of the laterite nickel ore high pressure acid leaching residue is 10-15%, and the particle size below 100um accounts for no less than 80%; the laterite nickel ore high pressure acid leaching residue contains 25-65% by mass of iron and 0.2-12% by mass of sulfur, and SO4 2- The sulfur content in the form of sulfur is greater than 2 / 3, among which the high-pressure acid leaching residue of laterite nickel ore is calculated on a dry basis.

[0014] As a preferred solution, the solid fuel is at least one of anthracite, coke powder, and lignite; the solid fuel has a moisture content of less than 10wt%, a fixed carbon content of greater than 60wt%, and a particle size of less than 74um accounts for more than 95%. In the present invention, when the moisture content of the solid fuel is too high, it is not conducive to mixing with the high-pressure acid leaching residue of laterite nickel ore, while when the fixed carbon content is too low, it cannot effectively provide sufficient heat to meet the sulfur removal temperature in the shell structure of the lower material particles. If the solid fuel particle size is too coarse, a localized, persistent, highly reducing atmosphere point will be formed in the core structure of the lower material particles, reducing the sulfate phase around the large particle fuel to sulfide, affecting the final oxidation removal effect of this type of sulfur.

[0015] As a preferred solution, the amount of the laterite nickel ore high pressure acid leaching residue and the solid fuel is based on the amount of SO4 in the laterite nickel ore high pressure acid leaching residue. 2-The ratio of the mass content of sulfur element in the form of carbon to the mass content of fixed carbon in the solid fuel is (1.5-2.5):1. When the content ratio is too low, that is, too much carbon is introduced, and a large amount of calcium sulfide intermediate phase is generated. Although the reaction between the intermediate phase and calcium sulfate can significantly increase the decomposition rate of calcium sulfate and achieve rapid removal of sulfur dioxide, it is ultimately difficult to completely oxidize and remove the excess intermediate phase in the core of the material particle, affecting the degree of sulfur removal. When the content ratio is too high, that is, insufficient carbon is introduced, the heat provided by the carbon is not enough to assist the external field heat to reach a sufficient temperature to remove SO4 2- Sulfur in the form of.

[0016] As a preferred solution, the particle size of the green ball material particle I is 8 to 14 mm, and the green ball material particle I and the green ball material particle I are 0 The particle size ratio of the raw ball material particles is (1.25-5):1; the particle size of the raw ball material particles II is 10-16 mm. 0 If the particle size ratio is too small, the shell structure of the pellets will be too thin, and the low melting point liquid phase generated by the core structure of the pellets may seep out, causing the liquid phase to stick together between the lower pellets, significantly reducing the permeability of the material layer, affecting the product quality and sulfur removal rate. 0 When the particle size ratio is too large, the core of the particle is too small and the shell is too thick, the amount of carbon introduced is limited, and it cannot provide enough heat to cooperate with the external field heat to achieve SO4 2- The removal window temperature range of sulfur in the form of sulfur is 1185~1285℃.

[0017] As a preferred embodiment, the combined thickness of fabric layer II and fabric layer I is 100-550 mm, and the thickness ratio of fabric layer II to fabric layer I is (1-4):1. Compared to existing technologies, this invention enables processing at higher fabric thicknesses, significantly improving production efficiency. The thickness ratio of fabric layer II to fabric layer I is primarily affected by the temperature difference between the upper and lower surfaces of the belt roaster and can be adjusted as needed during actual operation.

[0018] As a preferred solution, the calcination temperature is 1185-1285° C., and the calcination time is 30-80 minutes.

[0019] As a preferred solution, the sulfur content of the iron-containing material is less than 0.2%, and the concentration of the sulfur dioxide flue gas is greater than 1%. The method of the present invention can achieve deep removal of iron and sulfur from laterite nickel ore high-pressure acid leaching residue.

[0020] As a preferred solution, the iron-containing material is used for iron ore agglomeration or ironmaking raw material sales; the sulfur dioxide flue gas is purified and used for sulfuric acid preparation and recycled to the laterite nickel ore high-pressure acid leaching process.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The present invention is based on the characteristics of the belt roasting process burner and the top-down heating mode of the reheated airflow. The upper material layer has a large amount of contact heat, high heat transfer efficiency and high temperature. The raw balls made by granulating the high-pressure acid leaching slag of laterite nickel ore separately are distributed in the upper material layer, and the high temperature generated by the external heat source of the raw balls is directly used to effectively remove the sulfur element in the slag of the upper material layer; the high-pressure acid leaching slag of laterite nickel ore is mixed with solid fuel and granulated, and then the raw balls with a core-shell structure grown by the slag separately are distributed in the lower material layer, realizing the internal and external dual heating mode of the raw balls, effectively overcoming the shortcomings of the belt roasting process that the lower material layer has a small amount of contact heat, low heat transfer efficiency and low temperature, efficiently removing the sulfur element in the slag of the lower material layer, and realizing stable desulfurization of the entire material layer within the slag desulfurization temperature window.

[0023] 2) The present invention pelletizes the lower material layer into internal and external structure segments, constructing a double-layer structure with laterite nickel ore high-pressure acid leaching residue and solid fuel raw material as the core and laterite nickel ore high-pressure acid leaching residue raw material as the shell. By adding solid fuel to the core structure, carbon is introduced, significantly reducing the decomposition temperature of the sulfur phase mainly composed of calcium sulfate, increasing the reaction rate, and increasing the internal porosity, improving the kinetic conditions of the sulfur removal reaction, achieving precise and rapid sulfur removal from the core of the lower material layer, and further facilitating the enrichment of sulfur dioxide in the flue gas. In addition, the presence of the shell structure can effectively prevent the adhesion phenomenon caused by the low-melting-point compounds formed by the direct pelletization of laterite nickel ore high-pressure acid leaching residue and solid fuel, facilitating the smooth operation of the process.

[0024] 3) Compared to a single slag pelletizing material distribution structure, this invention can increase the material layer thickness by up to 100 mm and productivity by up to 22%, thereby reducing slag processing costs. Furthermore, the increased material layer thickness leads to a corresponding increase in sulfur dioxide concentration in the flue gas, enabling harmless and resourceful utilization of the corresponding slag under low-sulfur conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of a method for efficiently treating high-pressure acid leaching residue of laterite nickel ore. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with preferred implementation cases, but is not intended to limit the scope of protection of the claims of the present invention.

[0027] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0028] Example 1

[0029] A method for efficiently treating laterite nickel ore high-pressure acid leaching residues comprises the following steps:

[0030] 1) Mix anthracite with 4.25wt% of mass content and laterite nickel ore high pressure acid leaching residue and then pelletize in disc pelletizer I 0 The pelletizing was carried out in the pelletizing process to obtain green pellets with a particle size of 6 mm. 0 The anthracite has a moisture content of 3.93wt%, a fixed carbon content of 80.25wt%, and a particle size of 74um and below, accounting for 100%; the laterite nickel ore high-pressure acid leaching residue has a moisture content of 10.5wt%, and a particle size of 100um and below, accounting for 90%;

[0031] In the raw pellets Ⅰ 0 On the basis of high pressure acid leaching residue of laterite nickel ore, the raw ball material Ⅰ 0 The pellets were further grown in the disc pelletizer I to obtain green pellets I with a core-shell structure and a particle size of 12 mm.

[0032] The high-pressure acid leaching residue of laterite nickel ore was pelletized separately in a disc pelletizer II to obtain green pellets II with a particle size of 14 mm;

[0033] 2) The green pellets I are distributed on the grate plate of the belt roasting machine to form a distribution layer I with a thickness of 100 mm, and then the green pellets II are distributed on the distribution layer I to form a distribution layer II with a thickness of 250 mm;

[0034] 3) The finished material layer enters the belt roasting machine for heat treatment to obtain clean iron-containing materials and high-concentration sulfur dioxide flue gas. The heat treatment process temperature of the roasting section is 1250°C and the time is 40 minutes.

[0035] In this embodiment, the high pressure acid leaching residue of laterite nickel ore (dry basis) contains 27.99% iron and 7.60% sulfur by mass, and the sulfur is in the form of SO4 2- The sulfur content in the form of sulfur is 95%. The clean iron-containing material obtained after heat treatment in step 3) contains 39.09% iron and 0.026% sulfur by mass, which can be used for smelting in the molten pool to recover iron raw materials. The average sulfur dioxide concentration in the flue gas in the first 1 / 4 section of the roasting treatment area along the trolley's travel direction is 1.25%. Sulfuric acid can be produced using a wet acid production process and recycled to the high-pressure acid leaching process of laterite nickel ore.

[0036] Example 2

[0037] A method for efficiently treating laterite nickel ore high-pressure acid leaching residues comprises the following steps:

[0038] 1) Mix anthracite with 4.25wt% of mass content and laterite nickel ore high pressure acid leaching residue and then pelletize in disc pelletizer I 0The pelletizing was carried out in the pelletizing process to obtain green pellets with a particle size of 7.5 mm. 0 The anthracite has a moisture content of 3.93wt%, a fixed carbon content of 80.25wt%, and a particle size of 74um and below, accounting for 100%; the laterite nickel ore high-pressure acid leaching residue has a moisture content of 10.5wt%, and a particle size of 100um and below, accounting for 90%;

[0039] In the raw pellets Ⅰ 0 On the basis of high pressure acid leaching residue of laterite nickel ore, the raw ball material Ⅰ 0 The pellets are further grown in a disc pelletizer I to obtain green pellets I with a core-shell structure and a particle size of 10 mm.

[0040] The high-pressure acid leaching residue of laterite nickel ore was pelletized in a disc pelletizer II to obtain green pellets II with a particle size of 15 mm.

[0041] 2) The green pellets I are distributed on the grate plate of the belt roasting machine to form a distribution layer I with a thickness of 250 mm, and then the green pellets II are distributed on the distribution layer I to form a distribution layer II with a thickness of 300 mm;

[0042] 3) The finished material layer enters the belt roasting machine for heat treatment to obtain clean iron-containing materials and high-concentration sulfur dioxide flue gas. The heat treatment process temperature of the roasting section is 1285°C and the time is 40 minutes.

[0043] In this embodiment, the high pressure acid leaching residue of laterite nickel ore (dry basis) contains 27.99% iron and 7.60% sulfur by mass, and the sulfur is in the form of SO4 2- The sulfur content in the form of sulfur is 95%. The clean iron-containing material obtained after heat treatment in step 3) contains 38.82% iron and 0.15% sulfur by mass, which can be used for smelting in the molten pool to recover iron raw materials. The average sulfur dioxide concentration in the flue gas in the first 1 / 4 section of the roasting treatment area along the trolley's travel direction is 2.08%. Sulfuric acid can be produced using a wet acid production process and recycled to the high-pressure acid leaching process of laterite nickel ore.

[0044] Example 3

[0045] A method for efficiently treating laterite nickel ore high-pressure acid leaching residues comprises the following steps:

[0046] 1) Mix anthracite with 4.5wt% of mass content and laterite nickel ore high pressure acid leaching residue and then pelletize in disc pelletizer I 0 The pelletizing was carried out in the pelletizing process to obtain the green pellets with a particle size of 4 mm. 0The anthracite has a moisture content of 3.93wt%, a fixed carbon content of 80.25wt%, and a particle size of 74um and below, accounting for 100%; the laterite nickel ore high-pressure acid leaching residue has a moisture content of 10.5wt%, and a particle size of 100um and below, accounting for 90%;

[0047] In the raw pellets Ⅰ 0 On the basis of high pressure acid leaching residue of laterite nickel ore, the raw ball material Ⅰ 0 The pellets were further grown in the disc pelletizer I to obtain green pellets I with a core-shell structure and a particle size of 11 mm.

[0048] The high-pressure acid leaching residue of laterite nickel ore was pelletized in a disc pelletizer II to obtain green pellets II with a particle size of 15 mm.

[0049] 2) Place green pellets I on the grate plate of the belt roasting machine to form a material layer I with a thickness of 240 mm, and then place green pellets II on the material layer I to form a material layer II with a thickness of 240 mm;

[0050] 3) The finished material layer enters the belt roasting machine for heat treatment to obtain clean iron-containing materials and high-concentration sulfur dioxide flue gas. The heat treatment process temperature of the roasting section is 1270°C and the time is 40 minutes.

[0051] In this embodiment, the high pressure acid leaching residue of laterite nickel ore (dry basis) contains 27.99% iron and 7.60% sulfur by mass, and the sulfur is in the form of SO4 2- The sulfur content in the form of sulfur is 95%. The clean iron-containing material obtained after heat treatment in step 3) contains 38.18% iron and 0.11% sulfur by mass, which can be used for smelting in the molten pool to recover iron raw materials. The average sulfur dioxide concentration in the flue gas in the first 1 / 4 section of the roasting treatment area along the trolley's travel direction is 1.84%. Sulfuric acid can be produced using a wet acid production process and recycled to the high-pressure acid leaching process of laterite nickel ore.

[0052] Comparative Example 1

[0053] A method for efficiently treating laterite nickel ore high-pressure acid leaching residues comprises the following steps:

[0054] 1) Anthracite was mixed with high pressure acid leaching residue of laterite nickel ore in an internal weight content of 4.25 wt% and then pelletized in a disc pelletizer I to obtain green pellets I (i.e. I / I) with a particle size of 12 mm. 0 Equal to 1:1, shell-free structure), of which the anthracite has a moisture content of 3.93wt%, a fixed carbon content of 80.25wt%, and a particle size of 74um or less accounting for 100%; the laterite nickel ore high-pressure acid leaching residue has a moisture content of 10.5wt% and a particle size of 100um or less accounting for 90%;

[0055] The high-pressure acid leaching residue of laterite nickel ore was pelletized separately in a disc pelletizer II to obtain green pellets II with a particle size of 14 mm;

[0056] 2) The green pellets I are distributed on the grate plate of the belt roasting machine to form a distribution layer I with a thickness of 100 mm, and then the green pellets II are distributed on the distribution layer I to form a distribution layer II with a thickness of 250 mm;

[0057] 3) The finished material layer enters the belt roasting machine for heat treatment to obtain clean iron-containing materials and high-concentration sulfur dioxide flue gas. The heat treatment process temperature of the roasting section is 1250°C and the time is 40 minutes.

[0058] In this embodiment, the high pressure acid leaching residue of laterite nickel ore (dry basis) contains 27.99% iron and 7.60% sulfur by mass, and the sulfur is in the form of SO4 2- The sulfur content in the form of carbon is 95%. After heat treatment in step 3), the lower layer of material melts and bonds, preventing the process from proceeding smoothly. This is because the introduction of carbon lowers the decomposition point of the sulfur-containing calcium sulfate phase, significantly increasing the sulfur removal rate. However, the chemical components in the slag react with the carbon to form low-melting-point liquid compounds. Without the protection of a high-melting-point shell structure, the particles melt and bond directly.

[0059] Comparative Example 2

[0060] A method for efficiently treating laterite nickel ore high-pressure acid leaching residues comprises the following steps:

[0061] 1) Mix anthracite with 4.25wt% of mass content and laterite nickel ore high pressure acid leaching residue and then pelletize in disc pelletizer I 0 The pelletizing was carried out in the pelletizing process to obtain the green pellets with a particle size of 1 mm. 0 The anthracite has a moisture content of 3.93wt%, a fixed carbon content of 80.25wt%, and a particle size of 74um and below, accounting for 100%; the laterite nickel ore high-pressure acid leaching residue has a moisture content of 10.5wt%, and a particle size of 100um and below, accounting for 90%;

[0062] In the raw pellets Ⅰ 0 On the basis of high pressure acid leaching residue of laterite nickel ore, the raw ball material Ⅰ 0 The pellets are further grown in a disc pelletizer I to obtain green pellets I with a core-shell structure and a particle size of 10 mm.

[0063] The high-pressure acid leaching residue of laterite nickel ore was pelletized in a disc pelletizer II to obtain green pellets II with a particle size of 15 mm.

[0064] 2) The green pellets I are distributed on the grate plate of the belt roasting machine to form a distribution layer I with a thickness of 250 mm, and then the green pellets II are distributed on the distribution layer I to form a distribution layer II with a thickness of 300 mm;

[0065] 3) The finished material layer enters the belt roasting machine for heat treatment to obtain clean iron-containing materials and high-concentration sulfur dioxide flue gas. The heat treatment process temperature of the roasting section is 1285°C and the time is 40 minutes.

[0066] In this embodiment, the high pressure acid leaching residue of laterite nickel ore (dry basis) contains 27.99% iron and 7.60% sulfur by mass, and the sulfur is in the form of SO4 2- The sulfur content in the form of sulphur accounts for 95%. The clean iron-containing material obtained after the heat treatment in step 3) contains 37.55% iron and 1.22% sulfur by mass. The sulfur content is greater than 0.2%, which is not conducive to the use of iron ore agglomeration / ironmaking process.

[0067] Compared with Example 2, the green ball material Ⅰ and green ball material Ⅰ 0 The particle size ratio is too large, the core of the particle is too small and the shell is too thick, the amount of carbon introduced is limited, the heat of the lower material layer is insufficient, and the sulfur removal effect is reduced.

[0068] Comparative Example 3

[0069] A method for efficiently treating laterite nickel ore high-pressure acid leaching residues comprises the following steps:

[0070] 1) Anthracite was mixed with high pressure acid leaching residue of laterite nickel ore at a mass content of 3.0 wt% and then pelletized in disc pelletizer I 0 The pelletizing was carried out in the pelletizing process to obtain the green pellets with a particle size of 4 mm. 0 The anthracite has a moisture content of 3.93wt%, a fixed carbon content of 80.25wt%, and a particle size of 74um and below, accounting for 100%; the laterite nickel ore high-pressure acid leaching residue has a moisture content of 10.5wt%, and a particle size of 100um and below, accounting for 90%;

[0071] In the raw pellets Ⅰ 0 On the basis of high pressure acid leaching residue of laterite nickel ore, the raw ball material Ⅰ 0 The pellets were further grown in the disc pelletizer I to obtain green pellets I with a core-shell structure and a particle size of 11 mm.

[0072] The high-pressure acid leaching residue of laterite nickel ore was pelletized in a disc pelletizer II to obtain green pellets II with a particle size of 15 mm.

[0073] 2) Place green pellets I on the grate plate of the belt roasting machine to form a material layer I with a thickness of 240 mm, and then place green pellets II on the material layer I to form a material layer II with a thickness of 240 mm;

[0074] 3) The finished material layer enters the belt roasting machine for heat treatment to obtain clean iron-containing materials and high-concentration sulfur dioxide flue gas. The heat treatment process temperature of the roasting section is 1270°C and the time is 40 minutes.

[0075] In this embodiment, the high pressure acid leaching residue of laterite nickel ore (dry basis) contains 27.99% iron and 7.60% sulfur by mass, and the sulfur is in the form of SO4 2- The sulfur content in the form of sulphur accounts for 95%. The clean iron-containing material obtained after the heat treatment in step 3) contains 37.36% iron and 1.33% sulfur by mass. The sulfur content is greater than 0.2%, which is not conducive to the use of iron ore agglomeration / ironmaking process.

[0076] Compared with Example 3, when the carbon element is insufficiently introduced, the heat provided by the carbon is insufficient to assist the external field heat to reach a sufficient temperature to remove SO4 2- Sulfur in the form of.

Claims

1. A method for efficiently treating laterite nickel ore high-pressure acid leaching residue, characterized in that: The following steps are involved: 1) Mix the high pressure acid leaching residue of laterite nickel ore with solid fuel and then pelletize it in disc pelletizerⅠ 0 The pelletizing is carried out in the process to obtain green pellets Ⅰ 0 At the same time, the high pressure acid leaching residue of laterite nickel ore is pelletized separately in the disc pelletizer II to obtain green ball material II; the high pressure acid leaching residue of laterite nickel ore and the green ball material I are used to pelletize the green ball material II. 0 The pelletizing is continued in the disc pelletizer I to obtain green pellets I having a core-shell structure; 2) Place green pellets I on the grate plate of the belt roasting machine to form a layer I, and then place green pellets II on the layer I to form a layer II; 3) The finished material layer enters the belt roasting machine for heat treatment to obtain iron-containing materials and sulfur dioxide flue gas.

2. The method for efficiently treating laterite nickel ore high-pressure acid leaching residue according to claim 1, wherein: The moisture content of the high-pressure acid leaching residue of laterite nickel ore is 10-15wt%, and the proportion of particle size below 100um is not less than 80%; The laterite nickel ore high pressure acid leaching residue contains 25-65% iron and 0.2-12% sulfur by mass, and the sulfur is mainly SO4 2- The sulfur content in the form of sulfur is greater than 2 / 3, among which the high-pressure acid leaching residue of laterite nickel ore is calculated on a dry basis.

3. The method for efficiently treating laterite nickel ore high-pressure acid leaching residue according to claim 1, wherein: The solid fuel is at least one of anthracite, coke powder and blue charcoal; The solid fuel has a moisture content of less than 10 wt%, a fixed carbon content of more than 60 wt%, and a particle size of less than 74 μm accounts for more than 95%.

4. The method for efficiently treating laterite nickel ore high-pressure acid leaching residue according to any one of claims 1 to 3, characterized in that: The amount of the laterite nickel ore high pressure acid leaching residue and the solid fuel is based on the amount of SO4 in the laterite nickel ore high pressure acid leaching residue. 2- The ratio of the mass content of sulfur element in the form of sulfur to the mass content of fixed carbon in the solid fuel is (1.5~2.5):

1.

5. The method for efficiently treating laterite nickel ore high-pressure acid leaching residue according to claim 4, characterized in that: The particle size of the green ball material particle I is 8-14 mm, and the green ball material particle I and the green ball material particle I are 0 The particle size ratio is (1.25~5):1; the particle size of the green ball particle II is 10~16mm.

6. The method for efficiently treating laterite nickel ore high-pressure acid leaching residue according to claim 1, characterized in that: The sum of the thicknesses of the cloth layer II and the cloth layer I is 100-550 mm, and the thickness ratio of the cloth layer II to the cloth layer I is (1-4):

1.

7. The method for efficiently treating laterite nickel ore high-pressure acid leaching residue according to claim 6, characterized in that: The heat treatment conditions are: temperature of 1185-1285° C. and time of 30-80 min.

8. The method for efficiently treating laterite nickel ore high-pressure acid leaching residue according to claim 1, characterized in that: The sulfur content of the iron-containing material is less than 0.2% by mass, and the concentration of sulfur dioxide in the sulfur dioxide flue gas is greater than 1%.

9. The method for efficiently treating laterite nickel ore high-pressure acid leaching residue according to claim 1 or 8, characterized in that: The iron-containing material is used for iron ore agglomeration or ironmaking raw material sale; the sulfur dioxide flue gas is used for sulfuric acid preparation after purification and circulated to the high-pressure acid leaching process of laterite nickel ore.

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