Method for efficiently treating laterite-nickel ore high-pressure acid leaching residues

Abstract

The invention discloses a method for efficiently treating laterite-nickel ore high-pressure acid leaching residues, which comprises the following steps of: based on the characteristics that the temperature of an upper material layer is high and the temperature of a lower material layer is low in a top-to-bottom heat supply mode of a belt type roasting process burner and regenerative air flow, distributing green pellets which are separately granulated by residues on the upper material layer; and the slag and the solid fuel are mixed and granulated, and green pellets with core-shell structures are distributed on a lower material layer after the slag independently grows up. According to the method, sulfur in the slag pellets can be efficiently and stably removed under the condition of high material layer thickness, compared with a single slag pelletizing and distributing technology, the material layer thickness can be increased by 100 mm to the maximum extent, the productivity can be increased by 22% to the maximum extent, and the slag treatment process cost can be reduced.

Description

Technical Field

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

[0002] As an important industrial metal, nickel is widely used in the production of stainless steel, nickel-based alloys and ternary positive electrodes. Especially now, technological progress in the new energy industry and changes in market energy demand have directly promoted the rapid growth of projects in this field, which has led to a rapid increase in market demand for nickel.

[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. Under normal circumstances, the mining part of laterite nickel ore is generally divided into three parts from top to bottom: limonite layer, clay layer, and saprolitic layer. Among them, the limonite layer with low nickel grade and low silicon and magnesium content is suitable for wet treatment, accounting for 65% to 75%; the saprolitic layer with high nickel grade and low silicon and magnesium content is suitable for pyrometallurgical treatment, accounting for 15% to 25%; the clay layer between the two accounts for about 10%, and both wet and pyrometallurgical treatment are possible. Among them, the limonite-type laterite nickel ore with the largest metal reserves has received widespread attention. In the corresponding wet treatment process, the 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 the current wet smelting of low-grade limonite-type laterite nickel ore.

[0004] However, affected by the ore grade and smelting process, each ton of nickel metal produced will produce up to about 120 tons of high-pressure acid leaching slag, and the slag contains rich iron and sulfur elements. At present, HPAL slag is mainly stored directly, and the main components of iron and sulfur in the slag are not effectively utilized, resulting in serious waste of resources. At the same time, the leaching of harmful ions such as heavy metals and sulfate in the slag may cause great safety hazards to the local ecological environment. Therefore, it is urgent to treat HPAL slag harmlessly and recycle it.

[0005] On the one hand, the sulfur in the high-pressure acid leaching residue of laterite nickel ore mainly exists in the form of calcium sulfate, which has a high decomposition temperature; on the other hand, the high-pressure acid leaching residue of laterite nickel ore is affected by its small particle size, large specific surface area and chemical composition. When the temperature is too high, the particles are easy to melt. Under the joint restriction of these two aspects, the slag desulfurization process has a high temperature, a narrow window, and it is difficult to separate the iron and sulfur elements in depth. Belt machine pellet roasting is a mature and reliable process for preparing iron-making raw materials. The temperature is easy to control and the flue gas can be collected in sections, which provides a possibility for separating the iron and sulfur elements of the high-pressure acid leaching residue of laterite nickel ore and realizing resource utilization. However, the belt roasting process adopts a top-down heating mode using burners and reheated airflow. The upper material layer often has more contact heat, high heat transfer efficiency and high temperature, while the lower material layer has less contact heat, low heat transfer efficiency and low temperature. When the material layer is thick, the upper and lower temperature difference will exceed the desulfurization temperature window, resulting in the upper material layer temperature being at the upper limit of the desulfurization window. The temperature of the lower material layer is not enough to remove the sulfur content to the standard of <0.2%.

[0006] Therefore, developing a method for efficient treatment of high-pressure acid leaching slag 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 recycling. Summary of the invention

[0007] In view of the defects and shortcomings in the prior art, the purpose of the present invention is to provide a method for efficiently treating high-pressure acid leaching slag of laterite nickel ore. The method can achieve deep separation of iron and sulfur elements in high-pressure acid leaching slag pellets of laterite nickel ore under high material layer thickness conditions by reasonably distributing core-shell structured pellets and ordinary pellets and combining the characteristics of the top-down heating mode of the heat recovery airflow of the belt roasting machine. Compared with the single slag pelletizing and distribution technology, the material layer thickness can be increased by 100 mm at most, the productivity can be increased by 22% at most, 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 high-pressure acid leaching residues of laterite nickel ore, 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 the raw pellets Ⅰ 0 At the same time, the high pressure acid leaching residue of laterite nickel ore is pelletized separately in a disc pelletizer II to obtain raw ball material II; the high pressure acid leaching residue of laterite nickel ore and the raw ball material I are used 0 The pelletizing is continued in the disc pelletizing machine I to obtain green pellets I having a core-shell structure;

[0010] 2) Spreading the green ball material particles I onto the grate plate of the belt roasting machine trolley to form a material layer I, and then spreading the green ball material particles II onto the material layer I to form a material 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, so as to realize the internal and external dual heating mode of the small balls, effectively overcome the shortcomings of the belt roasting process that the lower material layer has less contact heat, low heat transfer efficiency and low temperature, efficiently remove the sulfur element in the slag of the lower material layer, and realize 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 ball, the decomposition temperature of the sulfur phase mainly composed of calcium sulfate is significantly reduced, the reaction rate is increased, and the internal porosity is increased, the kinetic conditions of the sulfur removal reaction are improved, and the sulfur in the slag is accurately and quickly removed. In addition, the existence of the shell structure can effectively prevent the adhesion phenomenon caused by the low-melting-point compounds generated by the high-pressure acid leaching residue of laterite nickel ore and the direct ball-making cloth of solid fuel, which is conducive to the smooth process.

[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 moisture content of the solid fuel is less than 10wt%, the fixed carbon content is greater than 60wt%, and the particle size below 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, and when the fixed carbon content is too small, it cannot effectively provide enough heat to meet the sulfur removal temperature in the shell structure of the lower layer of material particles. If the particle size of the solid fuel is too coarse, a local persistent high-reducing atmosphere point will be formed in the core structure of the lower layer of material particles, reducing the sulfate phase around the large particle fuel into 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, a large amount of calcium sulfide intermediate phase is generated. Although the reaction of the intermediate phase with 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 particles, 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 particles I is 8 to 14 mm, and the green ball material particles I and the green ball material particles I 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 is 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 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 solution, the sum of the thickness 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. Compared with the prior art, the present invention can achieve processing at a higher thickness of the material layer, significantly improving the production efficiency. Among them, the thickness ratio of the cloth layer II to the cloth layer I is mainly affected by the temperature difference between the upper and lower parts of the belt roasting machine, and can be adjusted as needed in actual operation.

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

[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 high-pressure acid leaching residue of laterite nickel ore.

[0020] As a preferred solution, 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 is recycled to the high-pressure acid leaching process of laterite nickel ore.

[0021] Compared with the prior art, the beneficial effects of the present invention include:

[0022] 1) The present invention is based on the characteristics of the belt roasting process burner and the heat recovery airflow from top to bottom. The upper material layer has more 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 less contact heat, low heat transfer efficiency and low temperature, and efficiently removing the sulfur element in the slag of the lower material layer, realizing stable desulfurization of the entire material layer within the slag desulfurization temperature window.

[0023] 2) The present invention performs segmented granulation of the raw balls of the lower material layer with internal and external structures, constructs a double-layer structure with laterite nickel ore high pressure acid leaching residue and solid fuel raw materials as the core and laterite nickel ore high pressure acid leaching residue raw materials as the shell, introduces carbon elements into the core structure by adding solid fuel, significantly reduces the decomposition temperature of the sulfur phase mainly composed of calcium sulfate, improves the reaction rate, and increases the internal porosity, improves the kinetic conditions of the sulfur element removal reaction, and realizes the accurate and rapid removal of sulfur from the core of the material particles in the lower material layer, which is more conducive to the enrichment of sulfur dioxide in the flue gas. In addition, the existence of the shell structure can effectively prevent the adhesion phenomenon caused by the low melting point compounds generated by the direct balling cloth of laterite nickel ore high pressure acid leaching residue and solid fuel, which is conducive to the smooth process.

[0024] 3) Compared with the single slag balling material distribution structure, the present invention can increase the material layer thickness by 100mm at most, and the productivity can be increased by 22% at most, which is conducive to reducing the cost of slag treatment process. In addition, benefiting from the increase in the thickness of the material layer, the concentration of sulfur dioxide in the flue gas increases accordingly, and the harmless and resourceful utilization of the corresponding slag under low sulfur content conditions can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a 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 examples, but is not intended to limit the protection scope of the claims of the present invention.

[0027] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional 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 high-pressure acid leaching residues of laterite nickel ore comprises the following steps:

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

[0031] In the raw ball material Ⅰ 0 Based on the 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 12 mm;

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

[0033] 2) The green ball material particles I are distributed on the grate plate of the belt roasting machine to form a material layer I with a thickness of 100 mm, and then the green ball material particles II are distributed on the material layer I to form a material 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, wherein 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 sulphur 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 concentration of sulfur dioxide in the flue gas in the first 1 / 4 section of the roasting treatment area along the direction of the trolley is 1.25%. Sulfuric acid can be prepared by 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 high-pressure acid leaching residues of laterite nickel ore comprises the following steps:

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

[0039] In the raw ball material Ⅰ 0 Based on the 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 is pelletized in a disc pelletizer II to obtain green pellets II with a particle size of 15 mm;

[0041] 2) The green ball material particles I are distributed on the grate plate of the belt roasting machine to form a material layer I with a thickness of 250 mm, and then the green ball material particles II are distributed on the material layer I to form a material 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, wherein 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 sulphur 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 concentration of sulfur dioxide in the flue gas in the first 1 / 4 section of the roasting treatment area along the direction of the trolley is 2.08%. Sulfuric acid can be prepared by 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 high-pressure acid leaching residues of laterite nickel ore comprises the following steps:

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

[0047] In the raw ball material Ⅰ 0 Based on the 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 11 mm;

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

[0049] 2) The green ball material particles I are distributed on the grate plate of the belt roasting machine to form a material layer I with a thickness of 240 mm, and then the green ball material particles II are distributed 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, wherein the heat treatment process temperature of the roasting stage 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 molten pool smelting to recover iron raw materials. The average concentration of sulfur dioxide in the flue gas of the first 1 / 4 section of the roasting treatment area along the direction of the trolley is 1.84%. Sulfuric acid can be prepared by 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 high-pressure acid leaching residues of laterite nickel ore comprises the following steps:

[0054] 1) Mixing anthracite with high pressure acid leaching residue of laterite nickel ore at a mass content of 4.25 wt% and pelletizing in a disc pelletizer I to obtain raw pellets I (i.e. I / I) with a particle size of 12 mm in one step. 0 Equal to 1:1, shellless structure), of which the moisture content of anthracite is 3.93wt%, the fixed carbon content is 80.25wt%, and the particle size below 74um accounts for 100%; the moisture content of high-pressure acid leaching residue of laterite nickel ore is 10.5wt%, and the particle size below 100um accounts for 90%;

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

[0056] 2) The green ball material particles I are distributed on the grate plate of the belt roasting machine to form a material layer I with a thickness of 100 mm, and then the green ball material particles II are distributed on the material layer I to form a material 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, wherein 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 slag accounts for 95%. After step 3) heat treatment, the lower material layer melts and bonds, and the process cannot proceed smoothly. This is because after the introduction of carbon, although the decomposition point of the calcium sulfate sulfur-containing phase is reduced and the sulfur removal rate is significantly improved, at the same time, the chemical components in the slag react with carbon to easily generate low-melting point liquid phase compounds. Without the protection of the high-melting point shell structure, the particles are directly melted and bonded.

[0059] Comparative Example 2

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

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

[0062] In the raw ball material Ⅰ 0 Based on the 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 is pelletized in a disc pelletizer II to obtain green pellets II with a particle size of 15 mm;

[0064] 2) The green ball material particles I are distributed on the grate plate of the belt roasting machine to form a material layer I with a thickness of 250 mm, and then the green ball material particles II are distributed on the material layer I to form a material 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, wherein 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 heat treatment in step 3) contains 37.55% iron and 1.22% sulfur by mass, and 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 raw ball material Ⅰ and the raw ball material Ⅰ 0 The particle size ratio is too large, the particle core is too small and the shell is too thick, the amount of carbon element 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 high-pressure acid leaching residues of laterite nickel ore comprises the following steps:

[0070] 1) Mix 3.0wt% of anthracite with high pressure acid leaching residue of laterite nickel ore and place it in a disc pelletizer I 0 The pelletization is carried out in the pelletizing process to obtain raw pellets with a particle size of 4 mm. 0 , of which the moisture content of anthracite is 3.93wt%, the fixed carbon content is 80.25wt%, and the particle size below 74um accounts for 100%; the moisture content of high-pressure acid leaching residue of laterite nickel ore is 10.5wt%, and the particle size below 100um accounts for 90%;

[0071] In the raw ball material Ⅰ 0 Based on the 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 11 mm;

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

[0073] 2) The green ball material particles I are distributed on the grate plate of the belt roasting machine to form a material layer I with a thickness of 240 mm, and then the green ball material particles II are distributed 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, wherein the heat treatment process temperature of the roasting stage 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 heat treatment in step 3) contains 37.36% iron and 1.33% sulfur by mass, and 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 high-pressure acid leaching residues of laterite nickel ore, 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 pelletizer I 0 The pelletizing is carried out in the process to obtain the raw pellets Ⅰ 0 At the same time, the high pressure acid leaching residue of laterite nickel ore is pelletized separately in a disc pelletizer II to obtain raw ball material II; the high pressure acid leaching residue of laterite nickel ore and the raw ball material I are used 0 The pelletizing is continued in the disc pelletizing machine I to obtain green pellets I having a core-shell structure; 2) Spreading the green ball material particles I onto the grate plate of the belt roasting machine trolley to form a material layer I, and then spreading the green ball material particles II onto the material layer I to form a material 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, characterized in that: The moisture content of the laterite nickel ore high-pressure acid leaching residue is 10-15wt%, and the proportion of particles with a particle size of less than 100um is not 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, wherein 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, characterized in that: 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 um accounts for more than 95%.

4. The method for efficiently treating high-pressure acid leaching residues of laterite nickel ore 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 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 raw ball material particles I is 8 to 14 mm, and the raw ball material particles I and the raw ball material particles I 0 The particle size ratio is (1.25-5):1; the particle size of the green ball particle II is 10-16 mm.

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 thickness 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 high-pressure acid leaching residue of laterite nickel ore 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 high-pressure acid leaching residue of laterite nickel ore according to claim 1, characterized in that: 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%.

9. The method for efficiently treating high-pressure acid leaching residue of laterite nickel ore according to claim 1 or 8, characterized in that: The iron-containing material is used for iron ore agglomeration or iron-making 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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