Method for producing high-quality composite ironmaking furnace charge from laterite-nickel ore high-pressure acid leaching residues

Abstract

The invention relates to a method for producing high-quality composite ironmaking furnace charge by using laterite-nickel ore high-pressure acid leaching residues, and belongs to the technical field of metallurgical solid waste recycling. The method comprises the following steps: premixing the laterite-nickel ore high-pressure acid leaching residues with high water content and quick lime to form a premix; uniformly mixing the premix with solid fuel, flux, return mine and iron ore powder, and granulating to obtain alkaline particles; the method comprises the following steps: pressing the laterite-nickel ore high-pressure acid leaching residues with low water content and solid fuel to form an acidic block mass; according to the method, high-alkalinity material particles and acid block masses are mixed and distributed to a sintering trolley to be sequentially ignited and sintered, composite iron-making furnace charge is obtained, the total iron (TFe) content of the composite iron-making furnace charge is larger than 52 wt%, the sulfur content of the composite iron-making furnace charge is smaller than 0.2 wt%, the drum strength (TI) of the composite iron-making furnace charge is larger than 70%, the reduction degree (RI) of the composite iron-making furnace charge is larger than 70%, and the composite iron-making furnace charge is suitable for the smelting reduction iron-making process. And the produced composite ironmaking furnace charge is excellent in performance and has remarkable economic and environmental benefits.

Description

Technical Field

[0001] The invention relates to a method for treating high-pressure acid leaching residue of laterite nickel ore, and in particular to a method for producing high-quality composite ironmaking furnace charge by utilizing high-pressure acid leaching residue of laterite nickel ore, belonging to the technical field of comprehensive utilization of metallurgy and industrial solid waste. Background Art

[0002] The high pressure acid leaching (HPAL) process of laterite nickel ore is an important method for extracting valuable metals such as nickel and cobalt. The amount of acid leaching slag produced is large, rich in iron and a large amount of silicon, aluminum, calcium, magnesium, sulfur and other components, and is an important secondary resource. At present, the utilization rate of high pressure acid leaching slag of laterite nickel ore is low, and most of it is treated by stockpiling or landfilling, which not only occupies land resources, but also contains heavy metal ions such as chromium, nickel, and cobalt, which may cause serious pollution to the environment. How to use high pressure acid leaching slag of laterite nickel ore efficiently and environmentally friendly has become an important topic in the field of comprehensive utilization of metallurgical resources.

[0003] In recent years, researchers have tried to use high-pressure acid leaching slag from laterite nickel ore as raw material for ironmaking. However, due to its physical properties and complex composition, there are many difficulties in using it directly in traditional pelletizing or sintering processes. In terms of pelletizing technology, the acid leaching slag from laterite nickel ore has fine particle size, many pores, and is very easy to absorb water. First, it is difficult to make slag balls, and second, the densification of the roasted balls is seriously insufficient. Its strength is far from meeting the requirements of blast furnace smelting. Other smelting methods can only be used to recover iron resources, such as side-blowing molten pool smelting. In terms of sintering technology, since the acid leaching slag from laterite nickel ore has strong water absorption and high viscosity, the moisture content of granulation is as high as 17% or more, which makes it difficult to mix the materials in the mixing stage, and the materials in the granulation stage are very easy to stick together, resulting in poor granulation effect. At the same time, high granulation moisture directly leads to the aggravation of the over-wetting phenomenon of the wet material belt during the sintering process, and even mudification. For the drying preheating zone, the small ball material particles are seriously broken and pulverized. The two lead to poor air permeability and high material layer resistance in the sintering process, and the process is difficult to run smoothly, which significantly affects the sintering ore and quality. At the same time, excessive moisture will take away a lot of heat, resulting in increased solid fuel consumption. In addition, due to the high silicon and high aluminum characteristics of the slag, the sintering process will promote the excessive generation of high-melting point and high-viscosity silicate and aluminate melts. The lack of fluidity of this type of liquid phase leads to poor permeability and poor uniform distribution. At the same time, the generation of the target bonding phase composite calcium ferrite (SFCA) is reduced, which ultimately leads to a simultaneous decrease in the mechanical strength and metallurgical properties of the sintered ore.

[0004] In terms of blast furnace smelting, based on historical background and from the perspective of high quality, high efficiency and low energy consumption, the blast furnaces in the industry basically adopt a charge structure mode of high basicity sintered ore combined with acidic oxidized pellets. Generally speaking, the charge is not only required to have appropriate basicity to ensure that the slag has good fluidity and desulfurization effect, but also requires good mechanical strength and excellent metallurgical properties, so as to provide a solid guarantee for the stable operation of the blast furnace and smelting efficiency.

[0005] Therefore, it is of great significance to develop a method that can efficiently utilize high-pressure acid leaching slag from laterite nickel ore and produce high-quality ironmaking charge. Summary of the invention

[0006] In view of the problems that the process of treating laterite nickel ore high-pressure acid leaching residue by traditional iron ore sintering process is difficult to proceed smoothly and the sintered ore is low in quality, the purpose of the present invention is to provide a method for large-scale production of high-quality composite ironmaking charge by using laterite nickel ore high-pressure acid leaching residue. The method has the advantages of low energy consumption and high economic benefits. The laterite nickel ore high-pressure acid leaching residue can be prepared into high-quality composite ironmaking charge to achieve large-scale and efficient recovery and utilization of iron resources in the laterite nickel ore high-pressure acid leaching residue. The method is reliable and conducive to industrial promotion.

[0007] In order to achieve the above technical purpose, the present invention provides a method for producing high-quality composite ironmaking furnace charge by using high-pressure acid leaching slag of laterite nickel ore, the method comprising the following steps:

[0008] 1) High pressure acid leaching residue of laterite nickel ore Premixing with quicklime to form a premix;

[0009] The laterite nickel ore high pressure acid leaching residue The moisture content is above 10wt.%;

[0010] 2) mixing the premix with solid fuel , flux, return ore and iron ore powder are mixed and granulated to obtain alkaline granules;

[0011] 3) High pressure acid leaching residue of laterite nickel ore and solid fuels The acid mass is formed by pressing;

[0012] The laterite nickel ore high pressure acid leaching residue The moisture content is less than 10wt.%;

[0013] 4) The high-basicity pellets and the acidic agglomerates are mixed and placed on a sintering trolley for sequential ignition and sintering to obtain a composite ironmaking charge.

[0014] Aiming at the technical problems existing in the process of treating laterite nickel ore high pressure acid leaching residue by the existing traditional iron ore sintering process, the key of the present invention lies in: on the one hand, the laterite nickel ore high pressure acid leaching residue with a higher water content is directly premixed with quicklime, and the active CaO in the quicklime is used to strongly adsorb the free water and capillary water in the laterite nickel ore high pressure acid leaching residue and carry out a digestion reaction. The digestion reaction has a volume expansion characteristic, which can block the pores of the laterite nickel ore high pressure acid leaching residue, and form a Ca(OH)2 adhesion layer with mild hydrophilicity and poor hygroscopicity in the slag pores and the outer surface of the slag, which effectively reduces the internal moisture and surface water absorption performance of the slag, and reduces the water required for granulation, thereby effectively improving the miscibility and granulation effect of the laterite nickel ore high pressure acid leaching residue. On the other hand, low-water-content laterite nickel ore high-pressure acid leaching slag is used to prepare acidic agglomerates with low moisture content, large particle size and high strength, and the acidic agglomerates are embedded in alkaline particles by mixed distribution, further reducing the overall moisture content of the raw material. At the same time, the large-sized acidic agglomerates are used to disrupt the accumulation of small-sized alkaline particles, improve the permeability of the material layer, optimize the heat transfer and mass transfer process of the material layer, and simultaneously achieve low consumption, high quality and high yield in the sintering process. In addition, the acidic agglomerates form dense and high-strength blocks through solid-phase consolidation, which limits the formation of aluminosilicate melts, while the alkaline particles provide SFCA molten bonding liquid phases, achieving deep bonding between the two, and synergistically improving the mechanical strength and metallurgical properties of the charge. In summary, the method of the present invention realizes the large-scale and efficient utilization of laterite nickel ore high-pressure acid leaching slag, and can prepare high-quality composite ironmaking furnace charges with excellent comprehensive performance and suitable alkalinity, which has significant economic and environmental benefits.

[0015] As a preferred solution, the CaO mass content of the quicklime is not less than 85%.

[0016] As a preferred solution, the laterite nickel ore high pressure acid leaching residue The moisture content is 10~15wt%. The laterite nickel ore acid leaching residue used When the moisture content of the high-pressure acid leaching slag I is too high, it is easy to stick together due to its high viscosity and low fluidity, making it difficult to mix evenly with quicklime; when the moisture content of the high-pressure acid leaching slag I of laterite nickel ore is too low, during the mixing process with quicklime, it is difficult for the quicklime to absorb a sufficient amount of free water and adsorbed water to react with it, and it is difficult to adhere to its surface to form a Ca(OH)2 adhesion layer, which cannot play the role of regulating the moisture content of subsequent granulation.

[0017] As a preferred solution, the solid fuel The solid fuel includes at least one of coke powder, anthracite, blue charcoal and biochar. As a preferred solution, the solid fuel The fixed carbon content is greater than 70wt% and the average particle size is 0.5-3mm. By controlling the appropriate fuel particle size, better fuel combustion efficiency can be achieved.

[0018] As a preferred solution, the flux includes at least one of limestone, dolomite and slaked lime.

[0019] As a preferred solution, the iron ore powder includes at least one of iron concentrate and iron ore powder.

[0020] As a preferred solution, the total iron content of the iron ore powder is greater than 55wt%. Too low an iron content will reduce the overall iron quality of the charge, increase the blast furnace coke ratio, and reduce smelting efficiency.

[0021] As a preferred solution, the ratio of solid fuel in the alkaline pellets is 5-10wt%. When the fixed carbon content of the solid fuel in the alkaline pellets is too low or its ratio is too low, it will lead to insufficient heat supply in the sintering process, low bed temperature, insufficient liquid phase generation, and poor sintered ore strength; when the fixed carbon ratio is too high, the bed temperature is too high, the liquid phase is excessively generated, and the permeability of the sintering process is seriously deteriorated, affecting the smooth process.

[0022] As a preferred solution, the quicklime accounts for 2-5% of the total dry mass of the alkaline material particles. If the quicklime ratio is too small or the CaO content is insufficient, a complete calcium hydroxide adhesion layer cannot be formed on the slag surface, and the pores cannot be blocked, the slag specific surface area can be reduced, and the hydrophilicity of the slag surface can be adjusted. If the quicklime ratio is too large, the chemical composition ratio of the sintered ore may be unbalanced, which is not conducive to the sintering process and mineralization reaction, and the sintered ore output and quality are significantly reduced.

[0023] As a preferred solution, the binary basicity of the alkaline material particles is 1.5-2.2, and the average size of the alkaline material particles is 3-8 mm. Appropriate binary basicity will be conducive to the formation of high-quality composite calcium ferrite binder phase. If the particle size of the alkaline material particles is too small, the matrix material has poor air permeability, which is seriously unfavorable for mass transfer and heat transfer during the sintering process. If the particle size of the alkaline material particles is too large, the sintering speed is too fast, the mineralization reaction is incomplete, and the strength of the sintered ore is reduced. The average size of the alkaline material particles is further preferably 4-6 mm.

[0024] As a preferred solution, the basic material particles contain the following chemical components and mass contents: SiO2 3-7%, Al2O3 1-4%, MgO 1-4%. Appropriate contents of SiO2, Al2O3, and MgO are important for sintering mineralization behavior and its mechanism. Too much or too little of these main chemical components will directly affect the final mechanical strength and metallurgical performance indicators of the sintered ore.

[0025] As a preferred solution, the laterite nickel ore acid leaching residue The moisture content is 4~8wt%, and the content of particles with a particle size less than 0.074mm is not less than 60wt%. When the moisture content of laterite nickel ore acid leaching slag II is too high or too low, it is not conducive to the agglomerate processing performance and strength index. The appropriate particle size content is conducive to further optimizing the pressing density and agglomerate strength.

[0026] As a preferred solution, the solid fuel The material comprises at least one of coke powder, anthracite, lignite and biochar.

[0027] As a preferred solution, the solid fuel The particle size is less than 0.074mm and the particle content is not less than 70wt%. When the particle size is too coarse, the coarse particles will form local persistent high reducing atmosphere points in the acidic agglomerates, reducing the surrounding sulfate phases into sulfides, affecting the final desulfurization effect.

[0028] As a preferred solution, the solid fuel in the acidic agglomerate The ratio is not higher than 4.5wt%.

[0029] The carbon element in the acidic agglomerate can reduce and decompose sulfate, and regulating its carbon content is helpful to promote desulfurization. When the fixed carbon content or ratio of the solid fuel in the acidic agglomerate is too low, the carbon element is insufficient. When the sulfur content of the high-pressure acid leaching slag of laterite nickel ore is high, it may lead to poor sulfur removal in the acidic agglomerate. When the ratio of the solid fuel is too high, that is, too much carbon is introduced, it is easy to cause the formation of calcium sulfide phase, which is difficult to completely oxidize and remove in the core area of ​​the acidic agglomerate, affecting the final sulfur removal degree of the charge. The ratio is more preferably 2~3wt%.

[0030] As a preferred solution, the binary basicity of the acidic agglomerates is less than 1.0, and the average size of the acidic agglomerates is 6-16 mm. If the particle size of the acidic agglomerates is too small, the effect of improving the air permeability of the material layer is poor; if the particle size of the acidic agglomerates is too large, on the one hand, the agglomerates cannot be fully consolidated under sintering conditions, resulting in a decrease in the final strength of the agglomerates, further affecting the strength index of the charge; on the other hand, it is difficult to remove the sulfur element inside the agglomerates, resulting in an excessive sulfur content in the final charge. The average size of the acidic agglomerates is further preferably 7-13 mm.

[0031] As a preferred solution, the compressive strength of the acidic agglomerate is 10-100 N. If the compressive strength of the raw acidic agglomerate is too low, it is easy to break during the mixing and distribution process, affecting the sintering process and final strength; if the compressive strength of the raw acidic agglomerate is too high, the compaction density of the pressed agglomerate is high, the kinetic conditions for sulfur removal in the agglomerate are poor, and it is not enough to completely remove the sulfur in the agglomerate under sintering conditions. The compressive strength during the pressing process is further preferably 20-60 N / piece.

[0032] As a preferred solution, the mixing mass ratio of the alkaline particles and the acidic agglomerates is 2:1~5:1. If the mixing ratio is too low, that is, the proportion of alkaline particles (matrix material) is too small, the amount of molten bonding liquid phase generated is insufficient, and the acidic agglomerates (embedded materials) cannot be well bonded and solidified, resulting in an imbalance in the overall structure, which leads to a decrease in the strength of the sintered ore; if the mixing ratio is too high, that is, the acidic agglomerates (embedded materials) are too few, it cannot play a good role in reducing the moisture of the overall material layer and improving the air permeability of the material layer. In addition, if the mixing ratio is too high or too low, the final pH of the sintered ore will be unbalanced, which is not conducive to subsequent blast furnace smelting.

[0033] As a preferred solution, the thickness of the cloth is 700-1000 mm. The sintering process has the characteristic of heat storage from top to bottom. Under the premise that the composite granulation cloth optimizes the air permeability, increasing the thickness of the sintering material layer as much as possible is conducive to improving the heat utilization efficiency and further reducing the solid fuel consumption in the sintering process.

[0034] As a preferred solution, the ignition temperature is 1100-1200°C, and the ignition time is 60-180s. If the ignition temperature is too low or the ignition time is too short, it is difficult to remove the sulfur in the surface sintered ore, which affects the sulfur content in the final sintered ore; if the ignition temperature is too high or the ignition time is too long, it is easy to cause excessive melting of the sintering material surface, forming an overmelting phenomenon, which not only directly leads to an increase in fuel consumption, but also causes the permeability of the material layer to deteriorate, resulting in a decrease in the sintered ore output and quality.

[0035] As a preferred solution, the sintering temperature is 1200-1400° C. If the sintering temperature is too low, the matrix material composed of the alkaline particles cannot generate enough molten bonding liquid phase, and the embedded material composed of the alkaline particles cannot be fully consolidated, both of which together cause the quality of the sintered ore to be significantly reduced; if the sintering temperature is too high, the matrix material composed of the alkaline particles is prone to generate excessive fayalite phase during the sintering process, and the formation of the favorable calcium ferrite phase is inhibited, which deteriorates the reduction performance of the sintered ore, thereby increasing the smelting load and energy consumption of the blast furnace.

[0036] As a preferred solution, the sulfur content in the high pressure acid leaching residue of laterite nickel ore (dry basis) of the present invention is less than 10wt%. When the sulfur content in the high pressure acid leaching residue of laterite nickel ore is too high, the sulfur content in the high density pressed acid agglomerate cannot be completely removed. It is further preferred that the sulfur content in the high pressure acid leaching residue of laterite nickel ore is less than 5wt%.

[0037] The composite ironmaking furnace charge obtained by the present invention has a total iron (TFe) content greater than 52wt%, a sulfur content less than 0.2wt%, a drum strength (TI) greater than 70%, and a reduction degree (RI) greater than 70%, and is suitable for a smelting reduction ironmaking process.

[0038] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0039] 1) Aiming at a series of problems caused by the strong water absorption and high viscosity of the high-pressure acid leaching residue of laterite nickel ore, such as high granulation moisture content and great difficulty in granulation, easy rupture and pulverization of the dried preheated pellets in the subsequent sintering process, serious over-wetting of the wet material, poor air permeability and high resistance of the material layer, and great difficulty in smooth process operation, the present invention innovatively proposes a granulation method particularly suitable for the acid leaching residue of laterite nickel ore, wherein the acid leaching residue of laterite nickel ore is premixed with quicklime to form a premix, and during the mixing process, CaO strongly absorbs the free water and capillary water in the slag, and at the same time, the characteristic that the volume of the digestion reaction of CaO will significantly expand is utilized to block the pores of the high-pressure acid leaching residue of laterite nickel ore, and a Ca(OH)2 adhesion layer with mild hydrophilicity and poor hygroscopicity is simultaneously formed on its surface, so as to synergistically reduce the internal moisture of the slag and the water absorption performance of the slag. In the subsequent mixing and granulation stages, on the one hand, the low-moisture premix is ​​easier to mix evenly with other raw materials; on the other hand, the added granulation water is not easily directly reabsorbed by the slag, but is more likely to stay in the gaps between the particles to form capillary water, which is conducive to rolling into ball granulation, thereby reducing the granulation water demand while enhancing the granulation effect.

[0040] 2) The present invention proposes a sintering method that is particularly suitable for high-pressure acid leaching residue of laterite nickel ore, in which acidic agglomerates are embedded in high-alkalinity matrix particles, wherein the acidic agglomerates have low moisture content, large particle size, and high strength, and the overall moisture content of the raw material can be further reduced. At the same time, large-sized acidic agglomerates can disrupt the regular stacking of small-sized alkaline particles, causing local voids to expand and form pores with better connectivity, effectively improving the permeability of the material layer, optimizing the heat and mass transfer process of the material layer, significantly reducing solid fuel consumption, and simultaneously improving the sintering mineral output and quality.

[0041] 3) The present invention aims at the problem of deterioration of sintering mineralization behavior caused by high silicon, high aluminum and other chemical components of high-pressure acid leaching slag of laterite nickel ore. The present invention adopts a mixed sintering method of acidic agglomerates and alkaline particles, wherein the acidic agglomerates utilize solid phase consolidation to form dense high-strength blocks to limit the formation of aluminosilicate melts, while the high-alkalinity matrix part with optimized composition provides SFCA molten bonding liquid phase to achieve deep interweaving of the two, synergistically improve the mechanical strength and metallurgical properties of the charge, and at the same time obtain high-quality composite ironmaking charge with excellent comprehensive performance and suitable alkalinity.

[0042] 4) The present invention can realize large-scale and efficient use of laterite nickel ore acid leaching slag to prepare high-quality composite ironmaking furnace charge: total iron (TFe)>52wt%, sulfur (S)<0.2wt%, drum strength (TI)>70%, reduction degree (RI)>70%, suitable for smelting reduction ironmaking process, the method is reliable, has significant economic and environmental benefits, and is conducive to industrial promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The present invention is a process flow chart for producing high-quality composite ironmaking furnace charge by utilizing high-pressure acid leaching slag from laterite nickel ore. DETAILED DESCRIPTION

[0044] 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.

[0045] 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.

[0046] Example 1

[0047] The raw material ratio of alkaline pellets is carried out according to mass percentage (dry basis), with a binary alkalinity of 1.8 and a granulation moisture of 15.5%, among which the solid fuel (coke powder, average particle size 1.7mm), quicklime (CaO content 90.5%), laterite nickel ore acid leaching residue (moisture 13.0%), iron ore powder (Australian ore underscreen powder), flux (dolomite 1.0% + limestone 7.1%), and return ore (internal mix) are 7.5%, 3.5%, 31.8%, 26.0%, 8.1%, and 23.1% respectively. First, the laterite nickel ore acid leaching residue and quicklime are pre-mixed to obtain a premix, and then the premix, solid fuel, iron ore powder, flux, and return ore are mixed and granulated in a cylinder to obtain an alkaline pellet with an average particle size of 5.1mm. The raw material ratio of acid pellets is based on mass percentage (dry basis), and the ratios of laterite nickel ore acid leaching residue (water content 5.0%, particle content less than 0.074mm accounts for 88.6%) and solid fuel (coke powder, particle content less than 0.074mm accounts for 87.3%) are 98.0% and 2.0% respectively. After mixing, they are pressed into agglomerates with an alkalinity of 0.031 and a particle size of 7.7mm by a briquetting machine, and the average compressive strength is 25N / piece. The alkaline pellets and acid pellets are further mixed in a ratio of 4:1, and the materials are manually placed in the sintering cup, and then ignited and sintered for sintering cup test. The physical and chemical characteristics of the raw materials are shown in Table 1, and the sintering indicators and main chemical components are shown in Table 2.

[0048] Example 2

[0049] The raw material ratio of alkaline pellets is carried out according to mass percentage (dry basis), with a binary alkalinity of 2.1 and a granulation moisture of 15.0, among which the solid fuel (coke powder, average particle size 1.7mm), quicklime (CaO content 90.5%), laterite nickel ore acid leaching residue (moisture 14.5%), iron ore powder (Australian ore underscreen powder), flux (dolomite 0.6% + limestone 9.0%), and return ore (internal mix) are 6.5%, 4.5%, 33.8%, 22.5%, 9.6%, and 23.1% respectively. First, the laterite nickel ore acid leaching residue and quicklime are pre-mixed to obtain a premix, and then the premix, solid fuel, iron ore powder, flux, and return ore are mixed and granulated in a cylinder to obtain an alkaline pellet with an average particle size of 5.0mm. The raw material ratio of acid pellets is based on mass percentage (dry basis), and the ratios of laterite nickel ore acid leaching residue (water content 6.0%, particle content less than 0.074mm accounts for 88.6%) and solid fuel (coke powder, particle content less than 0.074mm accounts for 87.3%) are 97.0% and 3.0% respectively. After mixing, they are pressed into agglomerates with an alkalinity of 0.032 and a particle size of 7.7mm by a briquetting machine, and the average compressive strength is 50N / piece. The alkaline pellets and acid pellets are further mixed in a ratio of 2:1, and the materials are manually distributed in the sintering cup with a thickness of 900mm. The subsequent ignition and sintering are tested by the sintering cup. The physical and chemical characteristics of the raw materials are shown in Table 1, and the sintering indicators and main chemical components are shown in Table 2.

[0050] Example 3

[0051] The raw material ratio of alkaline pellets is carried out according to mass percentage (dry basis), with a binary alkalinity of 1.8 and a granulation moisture of 16.0, wherein the solid fuel (coke powder, average particle size 1.7mm), quicklime (CaO content 90.5%), laterite nickel ore acid leaching residue (moisture 11.5%), iron ore powder (Australian ore underscreen powder), flux (dolomite 1.4% + limestone 6.1%), and return ore (internal mix) are 8.5%, 2.5%, 29.2%, 29.2%, 7.5%, and 23.1% respectively. First, the laterite nickel ore acid leaching residue and quicklime are pre-mixed to obtain a premix, and then the premix, solid fuel, iron ore powder, flux, and return ore are mixed and granulated in a cylinder to obtain an alkaline pellet with an average particle size of 5.3mm. The raw material ratio of acid pellets is based on mass percentage (dry basis), and the ratios of laterite nickel ore acid leaching residue (water content 7.0%, particle content less than 0.074mm accounts for 88.6%) and solid fuel (coke powder, particle content less than 0.074mm accounts for 87.3%) are 97.0% and 3.0% respectively. After mixing, they are pressed into agglomerates with an alkalinity of 0.033 and a particle size of 7.7mm by a briquetting machine, and the average compressive strength is 70N / piece. The alkaline pellets and acid pellets are further mixed in a ratio of 5:1, and the material is manually distributed in the sintering cup with a thickness of 700mm. The subsequent ignition and sintering are tested by the sintering cup. The physical and chemical characteristics of the raw materials are shown in Table 1, and the sintering indicators and main chemical components are shown in Table 2.

[0052] Comparative Example 1

[0053] The raw material ratio of alkaline pellets is carried out according to the mass percentage (dry basis), and the binary alkalinity is set at 1.8 and the granulation moisture is 15.5. Among them, the solid fuel (coke powder, average particle size 1.7mm), quicklime (CaO content 90.5%), laterite nickel ore acid leaching residue (moisture 13.0%), iron ore powder (Australian ore underscreen powder), flux (dolomite 1.0% + limestone 7.1%), and return ore (internal mix) are 7.5%, 3.5%, 31.8%, 26.0%, 8.1%, and 23.1% respectively. The laterite nickel ore acid leaching residue, quicklime, solid fuel, iron ore powder, flux, and return ore are directly mixed and granulated in a cylinder to obtain an alkaline pellet with an average particle size of 4.9mm, and then manually spread into the sintering cup with a thickness of 800mm. The subsequent ignition and sintering are tested for the sintering cup. The physical and chemical characteristics of the raw materials are shown in Table 1, and the sintering indicators and main chemical components are shown in Table 2.

[0054] Comparative Example 2

[0055] The raw material ratio of alkaline pellets is carried out according to mass percentage (dry basis), with a binary alkalinity of 1.8 and a granulation moisture of 15.5, wherein the solid fuel (coke powder, average particle size 1.7mm), quicklime (CaO content 90.5%), laterite nickel ore acid leaching residue (moisture 13.0%), iron ore powder (Australian ore underscreen powder), flux (dolomite 1.0% + limestone 7.1%), and return ore (internal mix) are 7.5%, 3.5%, 31.8%, 26.0%, 8.1%, and 23.1% respectively. First, the laterite nickel ore acid leaching residue and quicklime are pre-mixed to obtain a premix, and then the premix, solid fuel, iron ore powder, flux, and return ore are mixed and granulated in a cylinder to obtain alkaline pellets with an average particle size of 5.1mm. The raw material ratio of acid pellets is based on mass percentage (dry basis), and the ratios of laterite nickel ore acid leaching residue (water content 5.0%, particle content less than 0.074mm accounts for 88.6%) and solid fuel (coke powder, particle content less than 0.074mm accounts for 87.3%) are 98.0% and 2.0% respectively. After mixing, they are pressed into agglomerates with an alkalinity of 0.031 and a particle size of 7.7mm by a briquetting machine, and the average compressive strength is 120N / piece. The alkaline granules and alkaline pellets are further mixed in a ratio of 1:1, and the materials are manually placed in the sintering cup with a thickness of 800mm. The subsequent ignition and sintering are tested by the sintering cup. The physical and chemical characteristics of the raw materials are shown in Table 1, and the sintering indicators and main chemical components are shown in Table 2.

[0056]

[0057]

Claims

1. A method for producing high-quality composite ironmaking furnace charge using high-pressure acid leaching slag from laterite nickel ore, characterized in that: The following steps are involved: 1) High pressure acid leaching residue of laterite nickel ore Premixing with quicklime to form a premix; The laterite nickel ore high pressure acid leaching residue The moisture content is above 10wt.%; 2) mixing the premix with solid fuel , flux, return ore and iron ore powder are mixed and granulated to obtain alkaline granules; 3) High pressure acid leaching residue of laterite nickel ore and solid fuels The acid mass is formed by pressing; The laterite nickel ore high pressure acid leaching residue The moisture content is less than 10wt.%; 4) The high-basicity pellets and the acidic agglomerates are mixed and placed on a sintering trolley for sequential ignition and sintering to obtain a composite ironmaking charge.

2. The method for producing high-quality composite ironmaking furnace charge by using high-pressure acid leaching residue of laterite nickel ore according to claim 1, characterized in that: The CaO mass content of the quicklime is not less than 85%; and / or, The laterite nickel ore high pressure acid leaching residue The moisture content is 10~15wt%; and / or, The solid fuel Including at least one of coke powder, anthracite, semi-coke and biochar; and / or, The solid fuel The fixed carbon content is greater than 70wt%, and the average particle size is 0.5~3mm; and / or, The flux includes at least one of limestone, dolomite and slaked lime; and / or, The iron ore powder includes at least one of iron concentrate and iron ore powder; and / or, The total iron content of the iron ore powder is greater than 55wt%.

3. The method for producing high-quality composite ironmaking furnace charge by using high-pressure acid leaching residue of laterite nickel ore according to claim 1 or 2, characterized in that: The solid fuel in the alkaline pellets The ratio is 5~10wt%; and / or, The quicklime accounts for 2-5% of the total mass of the alkaline material particles on a dry basis; and / or, The binary basicity of the alkaline material particles is 1.5-2.2, and the average size of the alkaline material particles is 3-8 mm; and / or, The chemical components and mass contents of the alkaline granules are: SiO2 3-7%, Al2O3 1-4%, and MgO 1-4%.

4. The method for producing high-quality composite ironmaking furnace charge by using high-pressure acid leaching residue of laterite nickel ore according to claim 1, characterized in that: The laterite nickel ore acid leaching residue The moisture content is 4~8wt%, and the particle content of particles with a particle size less than 0.074mm is not less than 60wt%; and / or, The solid fuel The particle size is less than 0.074 mm and the particle content is not less than 70wt%.

5. The method for producing high-quality composite ironmaking furnace charge by utilizing high-pressure acid leaching residue of laterite nickel ore according to claim 1 or 4, characterized in that: The solid fuel in the acidic briquette The ratio is not higher than 4.5wt%; and / or, The binary basicity of the acidic agglomerates is less than 1.0, and the average size of the acidic agglomerates is 6-16 mm.

6. The method for producing high-quality composite ironmaking furnace charge by using high-pressure acid leaching residue of laterite nickel ore according to claim 5, characterized in that: The compressive strength of the acidic agglomerate is 10-100N.

7. The method for producing high-quality composite ironmaking furnace charge by using high-pressure acid leaching residue of laterite nickel ore according to claim 1, characterized in that: The mixing mass ratio of the alkaline particles to the acidic agglomerates is 2:1 to 5:

1.

8. The method for producing high-quality composite ironmaking furnace charge by using high-pressure acid leaching residue of laterite nickel ore according to claim 1, characterized in that: The thickness of the cloth is 700-1000 mm.

9. The method for producing high-quality composite ironmaking furnace charge by using high-pressure acid leaching residue of laterite nickel ore according to claim 1, characterized in that: The ignition temperature is 1100-1200° C., and the ignition time is 60-180 seconds.

10. The method for producing high-quality composite ironmaking furnace charge by using high-pressure acid leaching residue of laterite nickel ore according to claim 1, characterized in that: The sintering temperature is 1200-1400°C.

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