A method for treating laterite nickel ore acid leaching residue by double-side blowing

Abstract

The present application relates to the technical field of smelting, and discloses a method for treating acid leaching residue of laterite nickel ore by means of double-side blowing, which comprises the following steps: S1. mixing acid leaching residue of laterite nickel ore and flux as raw materials, and spraying the raw materials into oxygen-enriched air and fuel for side blowing oxidation smelting to obtain oxidation smelting flue gas and oxidation smelting slag, and separating the oxidation smelting flue gas to obtain acid raw material gas which is sent to a sulfuric acid production process to produce sulfuric acid; S2. adding a reducing agent to the oxidation smelting slag, and spraying the oxidation smelting slag into oxygen-enriched air and fuel for side blowing reduction smelting to obtain molten iron, reduction smelting flue gas and reduction smelting slag, adding a desulfurizing agent to the molten iron for desulfurization, and producing iron ingots from the desulfurized molten iron. The present application can realize comprehensive utilization of acid leaching laterite nickel ore residue, fully recover residual valuable metals Fe, Ni and Co, fully develop and utilize components such as valuable metals, sulfur and tailings, and output zero solid waste, and turn waste into treasure.

Description

Technical Field

[0001] This invention relates to the field of smelting technology, and specifically to a method for treating sulfuric acid leaching residue from laterite nickel ore using a double-sided blowing method. Background Technology

[0002] Currently, nickel ore worldwide is mainly divided into two categories: nickel sulfide ore and laterite nickel ore (referred to as "latite ore"). Based on proven reserves, the ratio of nickel sulfide ore to laterite nickel ore is approximately 1:3. Previously, the world primarily used nickel sulfide ore to produce metallic nickel and nickel compounds. However, with the depletion of nickel sulfide ore reserves, the production of nickel-based products is gradually shifting towards laterite nickel ore, which now accounts for a larger proportion than nickel sulfide ore.

[0003] With the continuous development of new energy industries such as electric vehicles and energy storage, the demand for nickel metal has been greatly stimulated, leading to more widespread investment in the production of nickel and cobalt, which can be used as raw materials for batteries, extracted from laterite nickel ore. However, the widespread application of wet acid leaching technology for laterite nickel ore will inevitably generate a large amount of solid waste from laterite nickel ore acid leaching slag.

[0004] However, existing technologies cannot effectively utilize this waste residue to efficiently recover sulfur and Fe, Ni, and Co metal elements, resulting in long-term stockpiling of the waste residue. This not only pollutes the environment, but also causes the residual Fe, Ni, and Co metal elements in the residue to be lost, resulting in the waste of potential metal-rich resources. Summary of the Invention

[0005] This invention provides a method for treating acid leaching residue of laterite nickel ore using a double-sided blowing method, which effectively utilizes the acid leaching residue of laterite nickel ore to efficiently recover sulfur and Fe, Ni, and Co metal elements.

[0006] In a first aspect, the present invention provides a method for treating acid leaching slag from laterite nickel ore using a double-sided blowing method, comprising the following steps: S1. Acid leaching slag of laterite nickel ore and flux are mixed as raw materials. Oxygen-enriched air and fuel are side-blown into the raw materials for side-blown oxidation smelting to obtain oxidation smelting flue gas and oxidation smelting slag. The acid-making raw gas obtained from the oxidation smelting flue gas is sent to the sulfuric acid production process to produce sulfuric acid. The acid production feed gas includes SO2; The side-blown oxidation smelting temperature is 1300-1450℃, and the time is 1-6 hours; The volume fraction of O2 in the oxygen-enriched air is 30-50%. The acid leaching residue of laterite nickel ore, by elemental mass percentage, includes S 3-14%, Fe 30-45%, Si 6-14%, Ni 0.07-0.09%, Al 5-6%, Co 0.01-0.03%, with the balance being oxygen, bound water, and unavoidable trace impurities.

[0007] S2. Add a reducing agent to the oxidizing smelting slag, then side-blown oxygen-enriched air and fuel are injected to carry out side-blown reduction smelting to obtain molten iron, reduction smelting flue gas and reduction smelting slag. Add a desulfurizing agent to the molten iron to desulfurize it, and make the desulfurized molten iron into iron ingots. The iron ingot contains iron, nickel, and cobalt. The mass ratio of the oxidative smelting slag to the reducing agent is 100:(20-40).

[0008] In one optional embodiment, the mass ratio of laterite nickel ore acid leaching slag to flux in S1 is 100:(15-35). In one optional embodiment, the volume fraction of O2 in the oxidative melting atmosphere during the side-blown oxidative melting process is 3-8%; the volume fraction of O2 in the oxidative melting atmosphere is the volume fraction of oxygen in the side-blown oxidative melting furnace relative to the total volume of all gases in the side-blown oxidative melting furnace; the volume fraction of O2 in oxygen-enriched air refers to the volume fraction of O2 in the oxygen-enriched air.

[0009] In one alternative embodiment, the flux includes one or more of limestone, quicklime, and dolomite.

[0010] In one optional embodiment, the reducing agent in S2 is a carbon-based reducing agent; Optionally, the carbon-based reducing agent includes one or more of lump coal, coke, semi-coke, and waste graphite.

[0011] In one optional embodiment, the side-blown reduction melting temperature in S2 is 1450-1600℃, and the melting time is 2-4h; Optionally, the volume fraction of O2 in the oxygen-enriched air during the side-blown reduction smelting is 50-70%.

[0012] In one alternative embodiment, the fuels for the side-blown oxidation smelting and the side-blown reduction smelting each independently include pulverized coal or natural gas.

[0013] In one optional embodiment, the desulfurizing agent in S2 includes one or more of quicklime, iron oxide scale, and calcined dolomite.

[0014] In one optional embodiment, the reduced smelting slag is water-quenched and then mixed with an activator and ground to obtain an active micro-powder-assisted cementitious material; The activator includes one or more of quicklime, hydrated lime, desulfurized gypsum, limestone, cement, and clinker; Optionally, the mass ratio of the water-quenched reduction smelting slag to the activator is 1:(0.5%-5%). Optionally, the specific surface area of ​​the active micro-powder-assisted cementitious material is 350 m². 2 / kg-420 m 2 / kg.

[0015] In one alternative implementation, the waste heat from the side-blown oxidizing smelting flue gas and the side-blown reducing smelting flue gas is used to generate electricity.

[0016] In one optional embodiment, the laterite nickel ore acid leaching residue in S1 further includes natural air drying and crushing drying pretreatment before mixing; Optionally, the particle size after crushing and drying pretreatment is less than 25mm; Optionally, the natural air drying time is 2-5 days; Optionally, the pulverizing and drying pretreatment is carried out by using the residual heat of the smelting flue gas for drying.

[0017] In one optional embodiment, the moisture content of the laterite nickel ore acid leaching residue after crushing and drying pretreatment is less than 10%.

[0018] In one optional embodiment, the side-blown reduction smelting flue gas is used for power generation and then subjected to dust removal, with the dust obtained from the dust removal being returned to the side-blown reduction smelting step.

[0019] The technical solution of this invention has the following advantages: 1. The present invention provides a method for treating acid leaching slag of laterite nickel ore using a double-side blowing method, comprising the following steps: S1. Mixing laterite nickel ore acid leaching slag and flux as raw materials, side-blowing oxygen-enriched air and fuel into the raw materials for side-blowing oxidation smelting, obtaining oxidation smelting flue gas and oxidation smelting slag, separating the acid-producing raw gas from the oxidation smelting flue gas and sending it to the sulfuric acid production process to produce sulfuric acid; the temperature of the side-blowing oxidation smelting is 1300-1450℃, and the time is 1-6h; the volume fraction of O2 in the oxygen-enriched air is 30-50%; S2. Adding a reducing agent to the oxidation smelting slag, and then side-blowing oxygen-enriched air and fuel for side-blowing reduction smelting, obtaining molten iron, reduction smelting flue gas and reduction smelting slag, adding a desulfurizing agent to the molten iron for desulfurization, and making the desulfurized molten iron into iron ingots; the iron ingots include iron and nickel elements; the mass ratio of the oxidation smelting slag to the reducing agent is 100:(20-40).

[0020] The dual-side-blowing method provided by this invention achieves efficient desulfurization through the side-blowing oxidation smelting process in S1, and incorporates flux for both desulfurization and melting. The resulting oxidation smelting flue gas is separated to obtain acid-producing feed gas, which is then fed into the sulfuric acid production process to produce sulfuric acid. Further deep reduction is achieved through the side-blowing reduction smelting in S2. This side-blowing molten reduction process efficiently reduces metals such as iron and nickel from the acid-leached slag into iron ingots, thus achieving recovery. This invention enables the comprehensive utilization of acid-leached laterite nickel ore slag, fully recovering valuable metals Fe, Ni, Co, and sulfur, and achieving effective utilization of solid waste resources.

[0021] In this application, the temperature of the side-blown oxidation smelting is set at 1300-1450℃, and the time is 1-6 hours; the volume fraction of O2 in the oxygen-enriched air is 30-50%. This setting can improve the oxidation reactivity of the melt in the furnace, accelerate the desulfurization rate, reduce flue gas production, and increase heat utilization efficiency.

[0022] In this application, the mass ratio of the oxidative smelting slag to the reducing agent is set to 100:(20-40), which serves to promote the reduction of metals in the slag, improve the metal reduction recovery rate of the slag, and reduce the metal loss rate of the tailings.

[0023] 2. In the method for treating acid leaching slag of laterite nickel ore by double-side blowing provided by the present invention, the reduction smelting slag described in step S2 is quenched in water and then mixed with an activator and ground to obtain an active micro powder auxiliary cementitious material; the side-blown reduction smelting flue gas is used for power generation and then dust is removed, and the dust obtained from the dust removal is returned to the side-blown reduction smelting step.

[0024] The active micro-powder obtained from the slag after smelting and reduction in a side-blown furnace is predominantly glassy and exhibits high alkali hydration activity. Therefore, the side-blown smelting and reduction method is the final process for obtaining high-value metal alloy products, especially in hydrometallurgical industrial areas where coal prices are relatively low and the demand for steam is high, where side-blowing has significant advantages.

[0025] This invention utilizes waste heat from flue gas, reducing overall production energy consumption and significantly improving heat utilization efficiency. It features high processing efficiency, large solid waste consumption, diverse product types, high total output value, and low overall production cost.

[0026] This invention enables the recovery of metallic elements such as Fe, Ni, and Co from acid-leached laterite ore slag. This reduces the amount of metal ore raw materials used in traditional metallurgy, and the remaining metal refining tailings can be processed into building materials, further reducing the natural mineral resources extracted for the building materials industry. Overall, this significantly improves the utilization efficiency of laterite nickel ore resources, fully utilizing the potential value of this valuable ore, resulting in substantial economic and social benefits. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a process flow diagram from Embodiment 1 of the present invention. Detailed Implementation

[0029] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0030] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0031] Technical approach of this invention: 1. After the laterite acid leaching residue is discharged from the filter press, it is first sent to the stockpile for natural storage for 2-5 days, so that it loses some of its free water through natural air drying, reducing its moisture content, which facilitates subsequent processing and reduces process energy consumption.

[0032] 2. After being air-dried, the laterite ore is transported to the crushing and dispersing process, and waste heat flue gas is introduced into the crushing and dispersing equipment. This further achieves the drying and dehydration of the acid-leached laterite ore residue, fully utilizing waste heat and reducing energy consumption in subsequent processing. It also facilitates crushing and dispersing, reducing the impact of the acid-leached residue's own stickiness on equipment production efficiency. Control of the drying and crushing process reduces the moisture content of the laterite ore acid-leached residue to below 10%, and the crushed particle size to less than 25mm.

[0033] 3. The dried and crushed laterite acid leaching residue, after being mixed with a certain proportion of flux (one or more of limestone, quicklime, and dolomite), is directly fed into an oxygen-enriched side-blown melting furnace for side-blown oxidation smelting. This process aims to convert sulfur elements in sulfur-containing minerals such as sulfates and sulfides in the laterite acid leaching residue into SO2 gas, which then enters the flue gas, achieving efficient sulfur removal and deacidification during the laterite acid leaching residue smelting process. The SO2-containing flue gas generated is then sent to the chemical production process to produce concentrated sulfuric acid. The proportion of flux added to the laterite acid leaching residue is calculated based on the content of acidic oxides such as SiO2 and Al2O3 in the residue. The material mixing ratio is laterite acid leaching residue: flux = 100: (15-35).

[0034] The smelting temperature of the laterite acid leaching residue in the oxygen-enriched side-blown smelting furnace is maintained at 1300-1450℃, and the atmosphere in the furnace is controlled as a neutral to weakly oxidizing atmosphere with an O2 concentration of 3-8%.

[0035] 4. In oxygen-enriched side-blown oxidation smelting, the volume fraction of O2 in the oxygen-enriched air is controlled at 30-50%. Pulverized coal or natural gas is used as fuel.

[0036] The oxidized slag produced from the oxygen-enriched side-blown smelting desulfurization process is directly fed into the oxygen-enriched side-blown reduction smelting furnace via a chute for reduction smelting. A reducing agent (such as lump coal, coke, semi-coke, and waste graphite) is added to the furnace, with a desulfurization slag:reducing agent ratio of 100:(20-40). The side-blown reduction smelting furnace uses oxygen-enriched combustion heating, and pulverized coal or natural gas can be used as fuel. Oxygen-enriched air is used for combustion, with the O2 volume fraction controlled at 50-70%.

[0037] Inside the reduction smelting furnace, the temperature of the melt inside the furnace is controlled at 1450-1600℃.

[0038] 5. After side-blown reduction smelting, the iron oxide in the slag is reduced to molten iron and settles at the bottom of the molten pool in the reduction furnace. After accumulating to a certain thickness at the bottom of the furnace, it is discharged from the taphole and poured into the tundish. A certain amount of desulfurizing agent (composed of quicklime, iron oxide scale, and calcined dolomite) is then added to the tundish. After the molten iron meets the desulfurization standards, qualified pig iron is obtained, which is then cast into ingots and sold to iron and steel smelting enterprises. To solve the problem of incomplete slag-iron settling and separation, a settling electric furnace process is added after the side-blown reduction smelting furnace. This process achieves the separation of metallic iron from the slag by reheating the slag in the reduction smelting furnace.

[0039] The residual Ni and Co high-value metal elements in the acid leaching residue of laterite ore can be reduced into the molten iron under the strong reducing atmosphere of the side-blown molten pool. These elements are beneficial to improving the performance of steel materials, such as corrosion resistance, and can reduce the amount of corresponding alloys added during steel production. This fully recovers the residual valuable metal elements in the slag and reduces resource waste.

[0040] 6. After the smelting slag accumulates to a certain thickness in the furnace, it is periodically discharged from the side-blown furnace through the slag outlet. It is then subjected to water quenching and rapid cooling to obtain water-quenched slag. An activator (the mass ratio of activator to the water-quenched reduced smelting slag is 1:(0.5%-5%)) is added to the water-quenched slag. After drying and grinding, the slag is reduced to a specific surface area of ​​350-420 μm². 2 / kg, thus obtaining the active micro-powder-assisted cementitious material.

[0041] 7. The flue gas generated by the side-blown oxidation smelting furnace and reduction smelting furnace undergoes secondary combustion within the furnace, and then generates electricity and low-pressure hot steam as byproducts. These are either sold as external products for use in laterite hydrometallurgical processes or for municipal use. The low-heat flue gas after power generation, after dust removal, is sent to the chemical acid production process to produce concentrated sulfuric acid, while the reduction smelting flue gas is sent to the drying and dispersing or water-quenched slag grinding process.

[0042] The main products of this technology are iron ingots and activated micro powder, while also producing concentrated sulfuric acid. Byproducts include waste heat power generation and steam. The concentrated sulfuric acid, electricity, and steam can be recycled for use in the hydrometallurgical process of laterite nickel ore. The pig iron is sold to steel or alloy companies, and the activated micro powder is sold to cement, concrete, backfilling, roadbed and other fields.

[0043] The beneficial effects of this application will be explained below with reference to specific embodiments.

[0044] Example 1 This embodiment provides a method for treating sulfuric acid leaching residue from laterite nickel ore using a dual-side blowing method, including the following steps: The mass fractions of the main elements in the acid leaching residue of laterite nickel ore to be treated are Fe 36%, Ni 0.08%, S 5%, Si 6%, Al 5%, and Co 0.02%. The listed metal elements mainly exist in the residue in the form of oxide or sulfide mineral phases, with the remainder being oxygen, bound water, and unavoidable trace impurities.

[0045] S1. After being naturally air-dried for 2 days, the laterite acid leaching residue is crushed and dispersed to a particle size of less than 25mm. After drying pretreatment, the moisture content is below 10%. It is then mixed with flux limestone (the mass ratio of laterite nickel ore acid leaching residue to flux is 100:15) and directly fed into a side-blown oxidation smelting furnace for desulfurization. Pulverized coal is used as fuel, and oxygen-enriched air with an oxygen volume fraction of 40% is injected as the combustion-supporting gas. The O2 volume fraction in the oxidation smelting atmosphere in the side-blown oxidation smelting furnace is controlled at 5%, the side-blown oxidation smelting temperature is 1400℃, and the smelting time is 2 hours. After the acid leaching residue is fed into the oxidation smelting furnace, it undergoes decomposition, melting, and sulfide oxidation processes. The sulfur-containing minerals in the residue decompose to form oxidation smelting furnace flue gas (containing SO2) and oxidation smelting slag. After the oxidation smelting slag accumulates to a certain depth in the furnace, the slag outlet is opened, and the oxidation smelting slag is directly fed into the side-blown reduction furnace via a slag trough. After the oxidative smelting flue gas is used for waste heat power generation and dust removal, the temperature is 300℃. The acid production raw gas separated from the oxidative smelting flue gas is sent to the sulfuric acid production process to produce concentrated sulfuric acid, and the sulfur recovery rate can reach 99.5%.

[0046] S2. Oxidized slag enters the reduction smelting furnace, and simultaneously, reducing agent lump coal (mass ratio of 100:20 to oxidized slag) is added to the furnace. Relying on the oxygen-rich atmosphere of 60% O2 volume fraction in the side-blown furnace and the heating conditions of pulverized coal combustion, the side-blown reduction smelting process is carried out in the furnace. The reduction smelting temperature is 1500℃ and the smelting time is 3 hours. The iron oxide in the oxidized slag is reduced to molten iron and settles at the bottom of the furnace. After accumulating to a certain thickness, it flows out from the taphole and enters the molten iron tundish. After desulfurization of the molten iron (the desulfurizing agent is quicklime, accounting for 1% of the molten iron mass), the ingots are cast and sold to steel companies. According to the test, the iron recovery rate reaches 96%, the nickel recovery rate reaches 92%, and the cobalt recovery rate reaches 80%. The mass content of nickel in the iron ingot is 0.2%, and the mass content of cobalt is 0.02%. After water quenching, the reduced smelting slag is mixed with an activator (desulfurized gypsum) (the mass ratio of the water-quenched reduced smelting slag to the activator is 1:3%), and then dried and ground to a specific surface area of ​​400 m². 2 / kg of active micro-powder material is obtained and sold as an auxiliary cementing material to building material and related enterprises. After the side-blown reduction smelting flue gas is used for power generation, it is subjected to dust removal to obtain flue dust and hot flue gas. The flue dust is returned to the side-blown reduction smelting step, and the waste heat of the hot flue gas is used for the drying pretreatment step of laterite nickel ore acid leaching slag.

[0047] The main products of this technology are iron ingots and active micro powders. It also produces concentrated sulfuric acid and generates waste heat for power generation and steam. The concentrated sulfuric acid, electricity, and steam can be recycled for use in the hydrometallurgical process of laterite nickel ore.

[0048] Example 2 This embodiment provides a method for treating sulfuric acid leaching residue from laterite nickel ore using a dual-side blowing method, including the following steps: The mass fractions of the main elements in the acid leaching residue of laterite nickel ore to be treated are Fe 36%, Ni 0.08%, S 5%, Si 6%, Al 5%, and Co 0.02%. The listed metal elements exist mainly in the form of oxides or sulfide mineral phases in the residue, with the remainder being oxygen, bound water, and unavoidable trace impurities.

[0049] S1. After being naturally air-dried for 2 days, the laterite acid leaching residue is crushed and dispersed to a particle size of less than 25mm. After drying pretreatment, the moisture content is below 10%. It is then mixed with flux limestone (the mass ratio of laterite nickel ore acid leaching residue to flux is 100:35) and directly fed into a side-blown oxidation smelting furnace for desulfurization. Natural gas is used as fuel, and oxygen-enriched air with an oxygen volume fraction of 50% is injected as the combustion-supporting gas. The volume fraction of O2 in the oxidation smelting atmosphere in the side-blown oxidation smelting furnace is controlled at 4%, the side-blown oxidation smelting temperature is 1450℃, and the smelting time is 6 hours. After the acid leaching residue is fed into the oxidation smelting furnace, it undergoes decomposition, melting, and sulfide oxidation processes. The sulfur-containing minerals in the residue decompose to form oxidation smelting furnace flue gas (containing SO2) and oxidation smelting slag. After the oxidation smelting slag accumulates to a certain depth in the furnace, the slag outlet is opened, and the oxidation smelting slag is directly fed into the side-blown reduction furnace via a slag trough. After the oxidative smelting flue gas is used for waste heat power generation and dust removal, the temperature is 300℃. The acid production raw gas separated from the oxidative smelting flue gas is sent to the sulfuric acid production process to produce concentrated sulfuric acid, and the sulfur recovery rate can reach 99.4%.

[0050] S2. Oxidation smelting slag enters the reduction smelting furnace, and simultaneously, reducing agent lump coal (mass ratio of 100:30 to oxidation smelting slag) is added to the furnace. Relying on the oxygen-rich atmosphere concentration of 60% O2 volume fraction in the side-blown furnace and the heating conditions of pulverized coal combustion, the side-blown reduction smelting process is carried out in the furnace. The reduction smelting temperature is 1550℃, and the reduction smelting time is 3 hours. The iron oxide in the oxidation smelting slag is reduced to molten iron and settles at the bottom of the furnace. After accumulating to a certain thickness, it flows out from the taphole and enters the molten iron tundish. After desulfurization of the molten iron (the desulfurizing agent is quicklime, accounting for 1% of the molten iron mass), the ingots are cast and sold to steel companies. According to the test, the iron recovery rate reaches 96%, the nickel recovery rate reaches 92%, and the cobalt recovery rate reaches 80%. The nickel mass content in the iron ingot is 0.18%, and the cobalt mass content is 0.04%. After water quenching, the reduced smelting slag is mixed with an activator (desulfurized gypsum) (the mass ratio of the water-quenched reduced smelting slag to the activator is 1:3%), and then dried and ground to a specific surface area of ​​400 m². 2 / kg of active micro-powder material is obtained and sold as an auxiliary cementing material to building material and related enterprises. After the side-blown reduction smelting flue gas is used for power generation, it is subjected to dust removal to obtain flue dust and hot flue gas. The flue dust is returned to the side-blown reduction smelting step, and the waste heat of the hot flue gas is used for the drying pretreatment step of laterite nickel ore acid leaching slag.

[0051] The main products of this technology are iron ingots and active micro powders. It also produces concentrated sulfuric acid and generates waste heat for power generation and steam. The concentrated sulfuric acid, electricity, and steam can be recycled for use in the hydrometallurgical process of laterite nickel ore.

[0052] Example 3 This embodiment provides a method for treating sulfuric acid leaching residue from laterite nickel ore using a dual-side blowing method, including the following steps: The mass fractions of the main elements in the acid leaching residue of laterite nickel ore to be treated are Fe 38%, Ni 0.08%, S 6%, Si 6.4%, Al 5.2%, and Co 0.02%. The listed metal elements mainly exist in the residue in the form of oxide or sulfide mineral phases, with the remainder being oxygen, bound water, and unavoidable trace impurities.

[0053] S1. After being naturally air-dried for 2 days, the laterite acid leaching residue is crushed and dispersed to a particle size of less than 25mm. After drying pretreatment, the moisture content is below 10%. It is then mixed with flux limestone (the mass ratio of laterite nickel ore acid leaching residue to flux is 100:20) and directly fed into a side-blown oxidation smelting furnace for desulfurization. Pulverized coal is used as fuel, and oxygen-enriched air with an oxygen volume fraction of 35% is injected as the combustion-supporting gas. The O2 volume fraction in the oxidation smelting atmosphere in the side-blown oxidation smelting furnace is controlled at 4%, the side-blown oxidation smelting temperature is 1350℃, and the smelting time is 1.5 hours. After the acid leaching residue is fed into the oxidation smelting furnace, it undergoes decomposition, melting, and sulfide oxidation processes. The sulfur-containing minerals in the residue decompose to form oxidation smelting furnace flue gas (containing SO2) and oxidation smelting slag. After the oxidation smelting slag accumulates to a certain depth in the furnace, the slag outlet is opened, and the oxidation smelting slag is directly fed into the side-blown reduction furnace via a slag trough. After the oxidative smelting flue gas is used for waste heat power generation and dust removal, the temperature is 300℃. The acid production raw gas separated from the oxidative smelting flue gas is sent to the sulfuric acid production process to produce concentrated sulfuric acid, and the sulfur recovery rate can reach 98%.

[0054] S2. Oxidized slag enters the reduction smelting furnace, and simultaneously, reducing agent lump coal (mass ratio of 100:30 to oxidized slag) is added to the furnace. Relying on the oxygen-rich atmosphere of 65% O2 volume fraction in the side-blown furnace and the heating conditions of pulverized coal combustion, the side-blown reduction smelting process is carried out in the furnace. The reduction smelting temperature is 1450℃, and the smelting time is 2.5h. The iron oxide in the oxidized slag is reduced to molten iron and settles at the bottom of the furnace. After accumulating to a certain thickness, it flows out from the taphole and enters the molten iron tundish. After desulfurization of the molten iron (the desulfurizing agent is quicklime, accounting for 1% of the molten iron mass), the ingots are cast and sold to steel companies. According to the test, the iron recovery rate reaches 97%, the nickel recovery rate reaches 92.3%, and the cobalt recovery rate reaches 82%. The mass content of nickel in the iron ingot is 0.21%, and the mass content of cobalt is 0.02%. After water quenching, the reduced smelting slag is mixed with an activator (desulfurized gypsum) (the mass ratio of the water-quenched reduced smelting slag to the activator is 1:2%) and then dried and ground to a specific surface area of ​​410 m². 2 / kg of active micro-powder material is obtained and sold as an auxiliary cementing material to building material and related enterprises. After the side-blown reduction smelting flue gas is used for power generation, it is subjected to dust removal to obtain flue dust and hot flue gas. The flue dust is returned to the side-blown reduction smelting step, and the waste heat of the hot flue gas is used for the drying pretreatment step of laterite nickel ore acid leaching slag.

[0055] The main products of this technology are iron ingots and active micro powders. It also produces concentrated sulfuric acid and generates waste heat for power generation and steam. The concentrated sulfuric acid, electricity, and steam can be recycled for use in the hydrometallurgical process of laterite nickel ore.

[0056] Example 4 This embodiment provides a method for treating sulfuric acid leaching residue from laterite nickel ore using a dual-side blowing method, including the following steps: The mass fractions of the main elements in the acid leaching residue of laterite nickel ore to be treated are Fe 32%, Ni 0.08%, S 7%, Si 6.7%, Al 5%, and Co 0.02%. The listed metal elements exist mainly in the form of oxides or sulfide mineral phases in the residue, with the remainder being oxygen, bound water, and unavoidable trace impurities.

[0057] S1. After being naturally air-dried for 2 days, the laterite acid leaching residue is crushed and dispersed to a particle size of less than 25mm. After drying pretreatment, the moisture content is below 10%. It is then mixed with flux limestone (the mass ratio of laterite nickel ore acid leaching residue to flux is 100:20) and directly fed into a side-blown oxidation smelting furnace for desulfurization. Pulverized coal is used as fuel, and oxygen-enriched air with an oxygen volume fraction of 30% is injected as the combustion-supporting gas. The O2 volume fraction in the oxidation smelting atmosphere in the side-blown oxidation smelting furnace is controlled at 4%, the side-blown oxidation smelting temperature is 1400℃, and the smelting time is 2.5 hours. After the acid leaching residue is fed into the oxidation smelting furnace, it undergoes decomposition, melting, and sulfide oxidation processes. The sulfur-containing minerals in the residue decompose to form oxidation smelting furnace flue gas (containing SO2) and oxidation smelting slag. After the oxidation smelting slag accumulates to a certain depth in the furnace, the slag outlet is opened, and the oxidation smelting slag is directly fed into the side-blown reduction furnace via a slag trough. After the oxidative smelting flue gas is used for waste heat power generation and dust removal, the temperature is 300℃. The acid production raw gas separated from the oxidative smelting flue gas is sent to the sulfuric acid production process to produce concentrated sulfuric acid, and the sulfur recovery rate can reach 99%.

[0058] S2. Oxidized slag enters the reduction smelting furnace, and simultaneously, reducing agent lump coal (mass ratio of 100:40 to oxidized slag) is added to the furnace. Relying on the oxygen-rich atmosphere of 50% O2 volume fraction in the side-blown furnace and the heating conditions of pulverized coal combustion, the side-blown reduction smelting process is carried out in the furnace. The reduction smelting temperature is 1600℃, and the smelting time is 3 hours. The iron oxide in the oxidized slag is reduced to molten iron and settles at the bottom of the furnace. After accumulating to a certain thickness, it flows out from the taphole and enters the molten iron tundish. After desulfurization of the molten iron (the desulfurizing agent is quicklime, accounting for 1% of the molten iron mass), the ingots are cast and sold to steel companies. According to the test, the iron recovery rate reaches 97.7%, the nickel recovery rate reaches 95%, and the cobalt recovery rate reaches 84%. The mass content of nickel in the iron ingot is 0.2%, and the mass content of cobalt is 0.02%. After water quenching, the reduced smelting slag is mixed with an activator (desulfurized gypsum) (the mass ratio of the water-quenched reduced smelting slag to the activator is 1:4%), then dried and ground to a specific surface area of ​​415 m². 2 / kg of active micro-powder material is obtained and sold as an auxiliary cementing material to building material and related enterprises. After the side-blown reduction smelting flue gas is used for power generation, it is subjected to dust removal to obtain flue dust and hot flue gas. The flue dust is returned to the side-blown reduction smelting step, and the waste heat of the hot flue gas is used for the drying pretreatment step of laterite nickel ore acid leaching slag.

[0059] The main products of this technology are iron ingots and active micro powders. It also produces concentrated sulfuric acid and generates waste heat for power generation and steam. The concentrated sulfuric acid, electricity, and steam can be recycled for use in the hydrometallurgical process of laterite nickel ore.

[0060] Example 5 This embodiment provides a method for treating sulfuric acid leaching residue from laterite nickel ore using a dual-side blowing method, including the following steps: The mass fractions of the main elements in the acid leaching residue of laterite nickel ore to be treated are Fe 36%, Ni 0.08%, S 5%, Si 6%, Al 5%, and Co 0.02%. The listed metal elements mainly exist in the residue in the form of oxide or sulfide mineral phases, with the remainder being oxygen, bound water, and unavoidable trace impurities.

[0061] S1. After being naturally air-dried for 2 days, the laterite acid leaching residue is crushed and dispersed to a particle size of less than 25mm. After drying pretreatment, the moisture content is below 10%. It is then mixed with flux limestone (the mass ratio of laterite nickel ore acid leaching residue to flux is 100:25) and directly fed into a side-blown oxidation smelting furnace for desulfurization. Pulverized coal is used as fuel, and oxygen-enriched air with an oxygen volume fraction of 35% is injected as the combustion-supporting gas. The O2 volume fraction in the oxidation smelting atmosphere in the side-blown oxidation smelting furnace is controlled at 5%, the side-blown oxidation smelting temperature is 1300℃, and the smelting time is 1.5 hours. After the acid leaching residue is fed into the oxidation smelting furnace, it undergoes decomposition, melting, and sulfide oxidation processes. The sulfur-containing minerals in the residue decompose to form oxidation smelting furnace flue gas (containing SO2) and oxidation smelting slag. After the oxidation smelting slag accumulates to a certain depth in the furnace, the slag outlet is opened, and the oxidation smelting slag is directly fed into the side-blown reduction furnace via a slag trough. After the oxidative smelting flue gas is used for waste heat power generation and dust removal, the temperature is 300℃. The acid production raw gas separated from the oxidative smelting flue gas is sent to the sulfuric acid production process to produce concentrated sulfuric acid, and the sulfur recovery rate can reach 98%.

[0062] S2. Oxidation smelting slag enters the reduction smelting furnace, and simultaneously, reducing agent lump coal (mass ratio of 100:30 to oxidation smelting slag) is added to the furnace. Relying on the oxygen-rich atmosphere of 65% O2 volume fraction in the side-blown furnace and the heating conditions of pulverized coal combustion, the side-blown reduction smelting process is carried out in the furnace. The reduction smelting temperature is 1550℃, and the smelting time is 4 hours. The iron oxide in the oxidation smelting slag is reduced to molten iron and settles at the bottom of the furnace. After accumulating to a certain thickness, it flows out from the taphole and enters the molten iron tundish. After desulfurization of the molten iron (the desulfurizing agent is quicklime, accounting for 1% of the molten iron mass), the ingots are cast and sold to steel companies. According to the test, the iron recovery rate reaches 96.8%, the nickel recovery rate reaches 90%, and the cobalt recovery rate reaches 79.6%. The mass content of nickel in the iron ingot is 0.2%, and the mass content of cobalt is 0.02%. After water quenching, the reduced smelting slag is mixed with an activator (desulfurized gypsum) (the mass ratio of the water-quenched reduced smelting slag to the activator is 1:4.5%), and then dried and ground to a specific surface area of ​​412 m². 2 / kg of active micro-powder material is obtained and sold as an auxiliary cementing material to building material and related enterprises. After the side-blown reduction smelting flue gas is used for power generation, it is subjected to dust removal to obtain flue dust and hot flue gas. The flue dust is returned to the side-blown reduction smelting step, and the waste heat of the hot flue gas is used for the drying pretreatment step of laterite nickel ore acid leaching slag.

[0063] The main products of this technology are iron ingots and active micro powders. It also produces concentrated sulfuric acid and generates waste heat for power generation and steam. The concentrated sulfuric acid, electricity, and steam can be recycled for use in the hydrometallurgical process of laterite nickel ore.

[0064] Comparative Example 1 This comparative example provides a method for treating sulfuric acid leaching residue from laterite nickel ore using a two-sided blowing method, which differs from Example 1 only in that: During the side-blown oxidation smelting process, the volume fraction of O2 in the oxygen-enriched air injected into the furnace was controlled at 25%, the side-blown oxidation smelting temperature was 1280℃, and the smelting time was 7 hours, with other parameters remaining unchanged. The resulting sulfur recovery rate was 82%.

[0065] Comparative Example 2 This comparative example provides a method for treating sulfuric acid leaching residue from laterite nickel ore using a two-sided blowing method, which differs from Example 1 only in that: In the side-blown reduction smelting process, the mass ratio of oxidative smelting slag to reducing agent lump coal was 100:15, with other parameters remaining unchanged. The results showed that Fe recovery was only 36%, Ni recovery was only 13%, and Co recovery was only 9%.

[0066] By comparing Examples 1-5 with Comparative Examples 1-2, it can be seen that, within the scope of the present invention, Examples 1-5 can maximize the desulfurization and deacidification treatment of acid leaching residue during the oxidation smelting stage, thereby increasing the sulfur recovery rate in the acid production feed gas (98-99.5%). Simultaneously, during the reduction smelting stage, it can achieve deep reduction of valuable metal elements, improving the recovery rate of valuable metal elements Fe, Ni, and Co, and reducing metal element loss.

[0067] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for treating acid leaching residue from laterite nickel ore using a double-sided blowing method, characterized in that, Includes the following steps: S1. Acid leaching slag of laterite nickel ore and flux are mixed as raw materials. Oxygen-enriched air and fuel are side-blown into the raw materials for side-blown oxidation smelting to obtain oxidation smelting flue gas and oxidation smelting slag. The acid-making raw gas separated from the oxidation smelting flue gas is sent to the sulfuric acid production process to produce sulfuric acid. The side-blown oxidation smelting temperature is 1300-1450℃, and the time is 1-6 hours; The volume fraction of O2 in the oxygen-enriched air is 30-50%. S2. Add a reducing agent to the oxidizing smelting slag, then side-blown oxygen-enriched air and fuel are injected to carry out side-blown reduction smelting to obtain molten iron, reduction smelting flue gas and reduction smelting slag. Add a desulfurizing agent to the molten iron to desulfurize it, and then make the desulfurized molten iron into iron ingots. The iron ingot contains iron, nickel, and cobalt. The mass ratio of the oxidative smelting slag to the reducing agent is 100:(20-40).

2. The method for treating acid leaching slag from laterite nickel ore using the double-sided blowing method according to claim 1, characterized in that, The mass ratio of laterite nickel ore acid leaching residue to flux in S1 is 100:(15-35). And / or, the volume fraction of O2 in the oxidizing atmosphere during the side-blown oxidizing smelting is 3-8%; And / or, the flux includes one or more of limestone, quicklime, and dolomite.

3. The method for treating acid leaching slag from laterite nickel ore using the double-sided blowing method according to claim 1, characterized in that, The reducing agent in S2 is a carbon-based reducing agent; Optionally, the carbon-based reducing agent includes one or more of lump coal, coke, semi-coke, and waste graphite.

4. The method for treating acid leaching slag from laterite nickel ore using the double-sided blowing method according to claim 1 or 3, characterized in that, The side-blown reduction smelting temperature in S2 is 1450-1600℃, and the smelting time is 2-4h; Optionally, the volume fraction of O2 in the oxygen-enriched air during the side-blown reduction smelting is 50-70%.

5. The method for treating acid leaching slag from laterite nickel ore using the double-sided blowing method according to claim 1 or 3, characterized in that, The desulfurizing agent in S2 includes one or more of quicklime, iron oxide scale, and calcined dolomite.

6. The method for treating acid leaching slag from laterite nickel ore using a double-sided blowing method according to any one of claims 1-3, characterized in that, The reduced smelting slag is quenched in water, mixed with an activator, and ground to obtain an active micro-powder-assisted cementitious material. The activator includes one or more of quicklime, hydrated lime, desulfurized gypsum, limestone, cement, and clinker; Optionally, the mass ratio of the water-quenched reduction smelting slag to the activator is 1:(0.5%-5%).

7. The method for treating acid leaching slag from laterite nickel ore using a double-sided blowing method according to any one of claims 1-3, characterized in that, The waste heat from the side-blown oxidizing smelting flue gas and the side-blown reducing smelting flue gas is used to generate electricity.

8. The method for treating acid leaching slag from laterite nickel ore using the double-sided blowing method according to claim 1 or 2, characterized in that, The acid leaching residue of laterite nickel ore in S1 also includes natural air drying and crushing and drying pretreatment before mixing; Optionally, the particle size after crushing and drying pretreatment is less than 25mm; Optionally, the natural air drying time is 2-5 days; Optionally, the pulverizing and drying pretreatment step involves drying using the residual heat from the smelting flue gas.

9. The method for treating acid leaching slag from laterite nickel ore using the double-sided blowing method according to claim 8, characterized in that, The moisture content of the laterite nickel ore acid leaching residue after crushing and drying pretreatment is below 10%.

10. The method for treating acid leaching slag from laterite nickel ore using a double-sided blowing method according to any one of claims 1-3, characterized in that, The side-blown reduction smelting flue gas is used for power generation and then subjected to dust removal. The dust obtained from the dust removal is returned to the side-blown reduction smelting step.

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