Method for decomposing nickel-molybdenum-iron alloy

Abstract

The invention belongs to the technical field of hydrometallurgy, and particularly discloses a method for decomposing nickel-molybdenum-iron alloy, which comprises the following steps of: performing sulfuric acid curing treatment on the nickel-molybdenum-iron alloy in advance, and then performing water leaching to obtain water leaching liquid enriched with Ni and Fe and water leaching residues containing residual metals including Mo; and then the water leaching residues are subjected to oxidation acid leaching treatment, and acid leaching liquid containing residual metal and acid leaching residues are obtained. Based on the technology, efficient and low-cost decomposition of valuable metal in the nickel-molybdenum-iron alloy and preliminary separation of molybdenum and iron nickel are facilitated, and conditions are created for subsequent separation, purification and enrichment of nickel and molybdenum and product preparation.

Description

Technical Field

[0001] This invention relates to a method for hydrometallurgical leaching and decomposition of nickel-molybdenum-iron alloys, belonging to the field of chemical metallurgy. Background Technology

[0002] In response to the problems of low metal recovery rate, low economic benefits of recycling, and serious waste of resources in the utilization of low-grade nickel and molybdenum resources, the smelting process of nickel-molybdenum symbiotic resources often first obtains nickel-molybdenum alloy intermediates, and then uses the alloy intermediates as raw materials for further decomposition, separation and purification to obtain nickel and molybdenum compounds.

[0003] For example, nickel-molybdenum ferroalloys can be produced by enriching valuable metals from resources such as nickel-molybdenum ore, nickel-molybdenum-containing waste catalysts, and waste alloys through pyrometallurgical processes such as oxidative roasting desulfurization and carbon reduction smelting. Related patents, such as CN112210634A, disclose a method and apparatus for preparing nickel-molybdenum ferroalloys using low-grade nickel-molybdenum ore; patent CN110527847A discloses a method for obtaining nickel-molybdenum ferroalloys from nickel-molybdenum ore. Through the above methods, nickel-molybdenum ferroalloys with the main components of 10-21% Mo, 5-11% Ni, 2-3% V, 45-60% Fe, 7-13% P, 1-2% As, and 7-11% Si can be obtained from low-grade raw materials containing Ni and Mo.

[0004] With the scarcity of high-grade nickel-molybdenum ore and other high-quality resources, and the increasing demand for metallic Ni, Mo and their compounds from various industries, nickel-molybdenum ferroalloys, as a primary product obtained by pyrometallurgical enrichment of low-grade nickel-molybdenum resources, have high recycling value.

[0005] Currently, alkaline decomposition of nickel-molybdenum-iron alloys is commonly used in industry. Patent CN1752228A discloses a method for oxidative roasting of metallurgical materials with sodium carbonate. This involves mixing nickel-molybdenum-iron alloy powder with alkaline reagents such as sodium carbonate, followed by mechanical activation to break down the alloy phase structure. Sodium carbonate is then added, and the mixture is roasted in air at 550℃–650℃ for 2 hours. Mo is converted to sodium molybdate and enters the solution, while Ni and Fe are enriched in the leaching residue, achieving selective leaching of Mo. Patent CN 101333601A discloses an alkaline decomposition method for alloy materials. This method involves mixing nickel-molybdenum-iron alloy with calcium oxide and sodium carbonate, followed by oxidative roasting. This significantly reduces the impurity leaching rate during alloy decomposition, and optimizes process parameters and indicators. However, the alkaline process decomposes nickel-molybdenum-iron alloys, with almost all Ni entering the slag, and valuable metals in the alloy are not fully recovered. At the same time, there are problems such as the sintering of materials during the oxidation roasting of alloy powder, which results in the required amount of alkali being far excessive, high reagent costs, and a large amount of unreacted free alkali entering the solution. The water leaching solution requires a large amount of acidic reagent to adjust the pH to acidic to meet the needs of the subsequent Mo recovery process.

[0006] Currently, oxidative acid leaching and related enhanced decomposition processes have become the mainstream technologies for decomposing valuable metals in various alloy wastes. However, the application of acid decomposition technology for nickel-molybdenum-iron alloys is still in its infancy. Related patents, such as CN201110309215.8, use sodium chlorate for acid leaching of desiliconized cobalt white alloy powder. Patent CN200810219451.9 uses an H2SO4-Cl2 system to decompose finely ground cobalt white alloy. Patent CN201410179598.5 uses an HCl-Cl2 system to decompose copper-cobalt alloys. Although direct oxidative acid leaching of alloys achieves ideal leaching rates, it suffers from problems such as the large amount of oxidant required to achieve ideal decomposition results and a lack of economic viability. Developing a new, efficient, economical acid decomposition process for nickel-molybdenum-iron alloys that allows for easy integration of the leaching solution with recycling processes is urgently needed. Summary of the Invention

[0007] In view of the lack of decomposition methods for nickel-molybdenum-iron alloys and the difficulty in adapting them to other alloy decomposition processes, this invention provides a decomposition method for nickel-molybdenum-iron alloys, aiming to enhance the decomposition effect of nickel-molybdenum-iron alloys while reducing material costs.

[0008] Alloy materials are characterized by their dense internal metallic phases, the presence of stable intermetallic compounds, and the presence of oxide films on their surfaces; therefore, they differ from conventional minerals and are more difficult to decompose and extract metals from. Furthermore, the alloying structures, phase compositions, elemental occurrence forms, and types of impurities in nickel-molybdenum-iron alloys are extremely complex, with multiple elements intermingling and forming various solid solution alloy phases and metallic compounds. Compared to common nickel-cobalt-iron alloys, copper-cobalt alloys, and nickel-based superalloys, the presence of Mo and its intermetallic compounds, as well as the formation of Mo heteropolyacid anions in acidic solutions, further increases the difficulty of extracting and initially separating the metallic elements.

[0009] To address the problem of the difficult decomposition of nickel-molybdenum-iron alloys and the various economic and environmental issues associated with traditional alkaline processes, existing technologies lack effective solutions. Furthermore, simply adopting conventional alloy or mineral metal extraction processes is not highly adaptable and still struggles to achieve the high decomposition rate and low-cost processing results required for industrial applications. To address this problem, this invention, through in-depth research, provides the following improved solution:

[0010] A method for decomposing a nickel-molybdenum-iron alloy involves pre-treating the alloy with sulfuric acid, followed by water leaching to obtain a water leaching solution enriched with Ni and Fe, and a water leaching residue containing residual metals including Mo; the water leaching residue is then subjected to oxidative acid leaching treatment to obtain an acid leaching solution containing residual metals and an acid leaching residue.

[0011] To address the challenge of decomposing and recovering nickel-molybdenum-iron alloys due to their unique alloying and physicochemical characteristics, this invention innovatively pre-treats them with sulfuric acid before proceeding with subsequent oxidative acid leaching. This synergistic effect is achieved through several key improvements. Firstly, the aging process initially decomposes nickel and iron, significantly reducing the amount of oxidant required. Secondly, it enables the initial separation of Ni, Fe, Mo, and other valuable metals, with Ni and Fe entering the leaching solution and Mo entering the slag. Furthermore, it improves the alloy's microstructure, transforming dense alloy particles into porous ones to enhance the subsequent oxidative acid leaching effect, improve material utilization, and increase the leaching rate of valuable metals. Therefore, the process described in this invention can efficiently decompose nickel-molybdenum-iron alloys, improving the overall metal extraction rate. Moreover, it significantly reduces material processing costs and achieves the initial separation of iron, nickel, molybdenum, and other valuable components, helping to reduce the difficulty of further extraction and utilization.

[0012] In this invention, the nickel-molybdenum-iron alloy can be any alloy containing nickel, molybdenum, and iron known in the industry. There are no particular requirements for the content of each component in the nickel-molybdenum-iron alloy. For example, considering the source of raw materials and the characteristics of the manufacturing process for producing the alloy, the nickel-molybdenum-iron alloy, by weight percentage, contains 10-80% (moreover 20-65%) of iron, 5-40% (moreover 10-20%) of molybdenum, and 3-60% (moreover 5-35%) of nickel.

[0013] Furthermore, the nickel-molybdenum-iron alloy is permitted to contain at least one element selected from vanadium, phosphorus, carbon, silicon, tungsten, aluminum, calcium, and cobalt. The content of other components is not particularly required; for example, the content of phosphorus (P) may be 0.5%–15%, and / or, Al 0.3%–5%, and / or, Si 1%–10%, and / or, W 0.1%–10%, and / or, V 0.1%–3%, and / or, Ca 0.1%–10%, and / or, C 0.1%–10%, and / or, Co 0.1%–10%.

[0014] In this invention, the nickel-molybdenum-iron alloy is first crushed and mixed with water to obtain a mixture; then it is mixed with sulfuric acid for sulfuric acid aging treatment.

[0015] There are no special requirements for the crushing and grinding method and process, and the particle size of the nickel-molybdenum-iron alloy after crushing and grinding can be reasonably adjusted according to the process requirements, for example, it can be less than 0.15mm.

[0016] The moisture content of the mixture is 0.5% to 30%, and can be further 5% to 30%.

[0017] The moisture content of the matured material, including the water generated during the matured reaction, is 1% to 50%.

[0018] In this invention, during the sulfuric acid aging process, the mass percentage concentration of the sulfuric acid solution in the system is 70% to 98%; the aging system temperature is 50℃ to 200℃.

[0019] Preferably, the mass ratio of sulfuric acid to nickel-molybdenum-iron alloy is 0.5 to 3:1; it can be further 1 to 2:1, and considering cost, it can be further 1 to 1.3:1.

[0020] In this invention, the temperature during the sulfuric acid aging process is between 50°C and 200°C; more specifically, between 80°C and 140°C. Temperature control during the aging process can be based on the self-exothermic reaction of the aging process.

[0021] In this invention, the sulfuric acid aging time is 1h to 72h, and considering the processing efficiency, it can be further preferred to be 2h to 24h.

[0022] In this invention, the sulfidation and aging process can selectively separate Fe, Ni and other metallic components such as Mo from the nickel-molybdenum-iron alloy, and can change the physicochemical structure of the alloy. This facilitates synergistic effects with subsequent oxidation and acid leaching processes, enhances the utilization rate of oxidants and other materials, reduces the amount of oxidant used, and improves the decomposition and recovery rate of metals.

[0023] There are no special requirements for the liquid-to-solid ratio during the water immersion process. Considering cost, it can be further set to 1:1 to 10:1 L / kg.

[0024] There are no special requirements for the temperature during the immersion stage, but considering the cost, it can be further set to 25℃~100℃;

[0025] There are no specific requirements for the immersion time, but considering the cost, it can be further extended to 20 min to 240 min;

[0026] In this invention, after the water immersion treatment, an aqueous immersion solution containing Ni and Fe is obtained, as well as components containing Mo and other components such as residual Ni and Fe present in the alloy as intermetallic compounds; then, an oxidative acid immersion treatment is performed on it to leach out the remaining metal elements in the water immersion residue and enrich them in the acid immersion solution.

[0027] In this invention, the water-leached residue is placed in an acidic solution containing an oxidizing agent for oxidative acid leaching treatment.

[0028] In this invention, the acid solution is an inorganic strong acid solution with a concentration of 1 mol / L to 8 mol / L. The inorganic strong acid is, for example, at least one of hydrochloric acid, sulfuric acid, and nitric acid.

[0029] In this invention, the oxidant includes, for example, one or more of nitric acid solution, sodium chlorate, chlorine, oxygen, and hydrogen peroxide solution.

[0030] The amount of acid and oxidant added during the oxidative pickling process shall not be less than the theoretical reaction amount of each valuable metal in the alloy. Considering cost, the weight ratio of acid to the initial nickel-molybdenum-iron alloy is 0.5–4:1, further to 0.8–1.2:1. The weight ratio of oxidant to the initial nickel-molybdenum-iron alloy is 0.5–5:1, further to 1–3.5:1, and even further to 1–2:1.

[0031] There are no special requirements for the liquid-to-solid ratio in the oxidation and acid leaching process. Considering cost, it can be further set to 1:1 to 10:1 L / kg.

[0032] There are no special requirements for the temperature of the oxidation and acid leaching process; however, considering the cost, it can be further set to 25℃~100℃.

[0033] There are no special requirements for the oxidation and acid leaching time; for example, it can be 0.5h to 24h, and considering the cost, it can be further extended to 1h to 8h.

[0034] In this invention, Mo is primarily enriched in the acid leaching solution; Ni is enriched in both the aqueous leaching solution and the acid leaching solution. Valuable metal elements such as Ni can be recovered from the aqueous leaching solution using conventional methods, recovering the valuable metals from the obtained aqueous and acid leaching systems. For example, Mo and other valuable metal elements can be recovered from the acid leaching solution.

[0035] Beneficial effects

[0036] To address the challenge of metal decomposition and separation due to the unique physicochemical characteristics of nickel-molybdenum-iron alloys, this invention innovatively provides a combined process of sulfuric acid aging and oxidative acid leaching. This process synergistically enhances the utilization rate of oxidants and other materials, reduces oxidant consumption, and improves the metal decomposition rate. Furthermore, it enables the preliminary separation of Fe, Ni, and Mo in the alloy, reducing the processing burden of subsequent recycling steps. Moreover, this process achieves full elemental utilization and low-cost, high-efficiency decomposition of valuable metals in nickel-molybdenum-iron alloys, demonstrating significant economic advantages. Attached Figure Description

[0037] Figure 1 This is a process flow diagram of the present invention. Specific implementation methods

[0038] The following description of the implementation process of the present invention is based on the accompanying drawings. The implementation methods described with reference to the accompanying drawings are exemplary and should not be considered as limiting the present invention.

[0039] This invention provides a method for extracting metals such as molybdenum, nickel, and vanadium from nickel-molybdenum-iron alloys, comprising the following steps:

[0040] (1) Crushing and screening of nickel-molybdenum-iron alloy: crushing the nickel-molybdenum-iron alloy and grinding and screening the alloy blocks to a certain particle size range.

[0041] (2) Heat preservation and curing: The treated alloy powder is mixed with water in a certain mass ratio and stirred evenly; sulfuric acid is added and stirred evenly to initiate the sulfation reaction. Heat is released through the dilution heat of sulfuric acid and its own chemical reaction to keep the curing sulfation reaction at a certain temperature to obtain solid curing material.

[0042] (3) Water immersion of the aged material under normal pressure: Add water to the aged material in step (2) according to the predetermined liquid-solid ratio, and immerse it in water at a certain stirring speed and temperature. After the reaction is completed, the liquid-solid mixture is separated into water immersion liquid and water immersion residue. The water immersion residue is washed to obtain washing liquid and water immersion residue.

[0043] (4) Oxidative leaching of water leaching residue: The water leaching residue obtained in step (3) and the acidic leaching agent are mixed at a certain liquid-solid ratio, then stirred and oxidized. After the predetermined reaction time is reached, the leaching slurry is separated by liquid-solid separation to obtain acidic leaching solution and acidic leaching residue.

[0044] (5) Separation and recovery of valuable metals from the leachate: Ni is further recovered from the aqueous leachate obtained in step (3). Mo and Ni are further recovered from the leachate obtained in step (4).

[0045] The sulfuric acid solution in step (1) has a mass percentage concentration of 90% to 98%; the sulfuric acid / alloy powder mass ratio is 0.5 to 3. The aging system temperature in step (1) is 50℃ to 200℃; the aging time is 1h to 72h.

[0046] In step (3), the leaching temperature is 25℃~100℃, further 40℃~100℃, the leaching time is 20min~240min, and the liquid-solid ratio during the leaching process is 1:1~10:1L / kg.

[0047] In steps (3) and (4), water is used as the washing liquid to wash the water-leached residue during the liquid-solid separation process. Part of the washing liquid is combined with the leachate, and the other part is used as the leachate. The ratio of the two is adjusted to obtain a better washing effect and a suitable leachate concentration.

[0048] In step (4), the acidic leaching agent is one of 1 mol / L to 8 mol / L hydrochloric acid, sulfuric acid, or nitric acid solution; the leaching oxidant is one or more of 65% to 68% nitric acid solution, sodium chlorate, oxygen, chlorine, or hydrogen peroxide solution. The amount of oxidant used is not less than the sum of the theoretical amounts of Mo and Ni required for the reaction in the calcined material.

[0049] In step (4), the acidic oxidation leaching temperature is 25℃~100℃, the stirring leaching time is 1h~8h, and the leaching liquid-solid ratio is 1:1~10:1L / kg.

[0050] The following examples illustrate the method of the present invention. The alloy used in the examples is produced by a factory that smelts nickel-molybdenum-iron alloy.

[0051] In the following examples, the unit for the liquid-to-solid ratio can be mL / g.

[0052] Example 1

[0053] The nickel-molybdenum-iron alloy used in the examples has the following main components listed in the table below:

[0054] Table 1 Composition of high-speed iron nickel-molybdenum ferroalloy

[0055]

[0056] Follow these steps:

[0057] (1) Crush and grind the nickel-molybdenum-iron alloy block into alloy powder with a particle size of less than 0.075 mm.

[0058] (2) Take the alloy powder, add 10% of its mass of water and mix well. Then add 98% sulfuric acid at a mass ratio of acid to alloy powder of 1.27. Keep the material at the actual aging temperature of 100℃ (±10℃) for 6 hours.

[0059] (3) Water was added to the matured solid material at a liquid-to-solid ratio of 3 ml / g, and the leaching temperature was maintained at 80℃, the stirring rate at 200 r / min, and the leaching time at 1 h. After the reaction, the filtration performance was good. The volume was measured and the filter residue and filtrate were analyzed to calculate the leaching rate.

[0060] (4) Leaching analysis of water: Fe 57.23%, Mo 0.89%, Ni 42.84%.

[0061] (5) The leaching residue was not ground. Sulfuric acid was added at a ratio of 0.88 (sulfuric acid / alloy powder mass ratio relative to the original alloy powder), and stirring was started for pre-reaction. 30% hydrogen peroxide was then added while stirring. The hydrogen peroxide mass ratio relative to the original alloy powder mass was 1.5. The leaching temperature was maintained at 80℃, the stirring rate at 400 r / min, the leaching time at 2 h, and the total liquid-to-solid ratio relative to the original alloy powder mass was approximately 5:1. After leaching, liquid and solid separation was achieved, and the filtration performance was excellent.

[0062] (6) Analysis and testing of oxidative acid leaching residue: total decomposition yield of residue: Mo 95.08%, Ni 97.67%.

[0063] Comparative Example 1

[0064] Compared with Example 1, the only difference is that sulfuric acid aging was not performed; instead, oxidative acid leaching was performed directly. That is, steps (2) to (4) were skipped, and the alloy powder was decomposed directly through step (5). Specifically, the alloy powder described in Example 1 was added to sulfuric acid at a sulfuric acid / alloy powder mass ratio of 1.37; then 30% hydrogen peroxide was added, with the mass ratio of added hydrogen peroxide to the original alloy powder being 1.5; the leaching temperature was maintained at 80°C, the stirring rate at 400 r / min, and the leaching time at 6 h. After leaching, liquid-solid separation was performed.

[0065] Direct oxidation acid leaching analysis: Leaching rate based on slag: Mo 46.27%, Ni 74.08%.

[0066] Under the same oxidant dosage, direct oxidation and acid leaching cannot effectively decompose nickel-molybdenum-iron alloys; Comparative Example 2

[0067] Compared with Comparative Example 1, the only difference is the change in the amount of hydrogen peroxide used in the direct oxidation acid leaching. The mass ratio of hydrogen peroxide added to the original alloy powder in groups A and B is 3 and 3.5, respectively.

[0068] A: Leaching rates based on slag: Mo 92.93%, Ni 96.36%.

[0069] B: Leaching rates of slag: Mo 94.54%, Ni 97.14%.

[0070] The direct acid leaching process is difficult to achieve a more thorough decomposition of the alloy by further increasing the amount of oxidant used, and the amount of oxidant required to achieve the ideal leaching rate is about 2.3 times that of this process, and the leaching effect is also slightly weaker than that of this process.

[0071] Comparative Example 3

[0072] Comparative Example 3 differs from Example 1 in that it uses an alkaline oxidation roasting-water immersion method to decompose the nickel-molybdenum-iron alloy, and is carried out according to the following steps:

[0073] (1) The nickel-molybdenum-iron alloy block is crushed into a black powder with a small particle size. The alloy powder after initial crushing is ground until the particle size is less than 0.075 mm.

[0074] (2) Add sodium carbonate to nickel-molybdenum-iron alloy powder at an alkali / alloy weight ratio of 0.54 and grind it evenly. Then put it into a muffle furnace and let air enter to react with the material. Roast at 700°C for 2 hours, then take out the roasted sand and cool it to room temperature.

[0075] (3) Add a certain amount of water to the calcined sand and mix. Maintain the water immersion temperature at 100℃, the stirring rate at 200r / min, and the leaching time at 2h. After the reaction is completed, filter the mixture, measure the volume, and analyze the filtrate to calculate the leaching rate.

[0076] (4) Leaching analysis: Mo 60.94%, Ni 0.03%.

[0077] Based on processing 1 ton of nickel-molybdenum-iron alloy, and assuming the final products after recovering Mo and Ni from the leaching solution are ammonium molybdate tetrahydrate (25 w / t) and nickel sulfate (3.8 w / t), and converting the hydrogen peroxide consumption to the commonly used 27.5% hydrogen peroxide in industry, the cost and benefit analysis of the main reagents in the above example is as follows:

[0078] Table 2. Cost of reagents for each process in Example 1.

[0079]

[0080] This method can employ cross-flow leaching, counter-flow leaching, and other decomposition processes depending on the raw material composition until the valuable metal content in the slag meets the requirements, thereby further improving the Mo yield of the decomposition process. Even ignoring the revenue from Mo recovered from the product, the sulfuric acid aging-oxidative acid leaching process reduces the reagent cost per ton of alloy by RMB 1272.01 compared to direct oxidative acid leaching for low-nickel alloys, demonstrating a more significant economic advantage. Compared to the alkaline decomposition process, even if the Mo in the alkaline water leaching slag can be further recovered through enhanced methods, ignoring the revenue from molybdenum products, this method converts the non-value-added Ni in the alloy into high-value Ni through a short-process, low-cost treatment. Processing one ton of nickel-molybdenum-iron alloy can simultaneously generate RMB 5294.49 in Ni product revenue, while the decomposition reagent cost is only RMB 601.37 higher than that of the alkaline method.

[0081] Example 2

[0082] Compared with Example 1, the only difference is that the object being processed and the following processing technology are changed. The nickel-molybdenum-iron alloy used has the main components listed in the table below:

[0083] Table 3 Composition of high-nickel nickel-molybdenum ferroalloy

[0084]

[0085] The main operating steps are the same as in Example 1, except that:

[0086] In step (2), 5% water by mass is added to the alloy powder, and 98% concentrated sulfuric acid is added at an acid / alloy mass ratio of 1.08. The material is kept at a temperature of about 90℃ (±10℃) for 3 hours for the actual aging process.

[0087] Step (3) Immerse in water at 95℃ for 30 minutes.

[0088] Leaching rates of the aqueous extract: Fe 38.02%, Mo 1.46%, Ni 37.62%.

[0089] Step (5) Sulfuric acid is added at an acid / alloy mass ratio of 0.97, and the mass ratio of hydrogen peroxide added to the original alloy powder is 3; the leaching temperature is maintained at 40℃, the leaching time is 6h, and the total liquid-solid ratio is approximately 8:1.

[0090] Leaching rates of oxidized acid leaching residue: Mo 90.14%, Ni 92.36%.

[0091] Comparative Example 4

[0092] Compared with Example 2, the only difference is that sulfuric acid aging was not performed, but oxidative acid leaching was performed directly; that is, the alloy powder decomposition and valuable metal leaching were achieved directly through step (5) without going through steps (2) to (4). The specific implementation operation is the same as that of Comparative Example 1. On this basis, the amount of oxidant was further increased. The experimental groups were: A, B, and C, where the mass ratio of hydrogen peroxide added to the original alloy powder was 3.5, 4, and 4.5, respectively.

[0093] A: Leaching rates based on slag: Mo 72.26%, Ni 74.26%.

[0094] B: Leaching rates of slag: Mo 80.27%, Ni 82.98%.

[0095] C: Leaching rates by slag: Mo 87.03%, Ni 89.45%.

[0096] This method also shows good adaptability to the decomposition of high-nickel alloys; it can also achieve better metal recovery results with lower oxidant dosage.

[0097] Comparative Example 5

[0098] Compared with Comparative Example 3, the only difference is that the raw materials of Example 2 are used, the nickel-molybdenum-iron alloy is decomposed based on the alkaline oxidation roasting-water leaching method of Comparative Example 3, and the mass ratio of sodium carbonate added to alkali / alloy powder in step 2 is further controlled to be 0.72.

[0099] Leaching analysis showed the following leaching rates: Mo 86.25%, Ni 0%.

[0100] Table 4. Cost of reagents for each process in Example 2

[0101]

[0102] The data above shows that this process also has certain economic advantages in treating high-grade nickel-molybdenum-iron alloys. Compared with the direct oxidation and acid leaching process, the reagent cost required to treat each ton of nickel-molybdenum-iron alloy is reduced by 1321.49 yuan. At the same time, a higher decomposition yield can be obtained under the conditions of room temperature oxidation and acid leaching. Compared with the alkaline decomposition process, the high-value nickel products created by this method in treating high-nickel nickel-molybdenum-iron alloys will have more significant benefits.

[0103] Example 3

[0104] The main operating steps and raw material processing are the same as in Example 1, except that:

[0105] In step (2), the alloy powder has a particle size of less than 0.15 mm. 30% water by mass is added, the acid / alloy mass ratio is 1.8, and the material is kept at an external heating source for 48 hours at a aging temperature of about 130℃ (±10℃).

[0106] Step (3) Immerse in water at 40°C for 240 min, with a water-to-solid ratio of 10:1.

[0107] Leaching rates of the aqueous extract: Fe 66.24%, Mo 1.98%, Ni 58.76%.

[0108] Step (5) Add 37% hydrochloric acid at an acid / alloy mass ratio of 2.43, with a Cl2 flow rate of 1L / min, a leaching temperature of 70℃, and a leaching time of 2h.

[0109] Leaching rates of oxidized acid leaching residue: Mo 91.28%, Ni 96.46%.

[0110] Example 4

[0111] The main operating steps and raw material processing are the same as in Example 1, except that:

[0112] In step (2), the alloy powder has a particle size of less than 0.075 mm. 10% water by mass is added, the acid / alloy mass ratio is 1.26, and the material is kept at an external heating source for 12 hours at a aging temperature of about 150℃ (±10℃).

[0113] Step (3) Immerse in water at 100℃ for 30 minutes, with a water-to-solid ratio of 2:1.

[0114] Leaching rates of the aqueous extract: Fe 51.23%, Mo 3.69%, Ni 49.06%.

[0115] Step (5) Sulfuric acid is added at an acid / alloy mass ratio of 0.92, and the mass ratio of 65% nitric acid added to the original alloy powder is 1.7. The leaching temperature is 80℃, the stirring rate is 300r / min, and the leaching time is 2h.

[0116] Leaching rates of oxidized acid leaching residue: Mo 92.14%, Ni 94.28%.

[0117] Example 5

[0118] The main operating steps and raw material processing are the same as in Example 1, except that:

[0119] In step (2), the alloy powder has a particle size of less than 0.075 mm. 20% water by mass is added, the acid / alloy mass ratio is 2.34, and the material is kept at an external heating source for 72 hours at a aging temperature of about 100℃ (±10℃).

[0120] Step (3) Immerse in water at 80℃ for 60 minutes, with a water-to-solid ratio of 3:1.

[0121] Leaching rates of the aqueous extract: Fe 64.69%, Mo 1.03%, Ni 53.75%.

[0122] Step (5) Add 37% hydrochloric acid at an acid / alloy mass ratio of 4.3, 65% nitric acid at an acid / alloy mass ratio of 0.58, and 30% hydrogen peroxide at a mass ratio of 0.45. Maintain the leaching temperature at 80°C, the stirring rate at 300 r / min, and the leaching time at 1 h.

[0123] Leaching rates of oxidized acid leaching residue: Mo 92.14%, Ni 94.28%.

[0124] The above description is merely a partial embodiment of the present invention and is not intended to limit the invention in any way. The technical essence of the present invention is to use a aging process to initially decompose the nickel-molybdenum-iron alloy and disrupt its phase structure; subsequently, an oxidative acid leaching process is used to achieve complete leaching of valuable metal elements from the nickel-molybdenum-iron alloy. Any simple modifications, equivalent changes, or alterations made to the above embodiments based on the technical essence of the present invention are within the protection scope of the present invention.

Claims

1. A method for decomposing nickel-molybdenum-iron alloys, characterized in that, The nickel-molybdenum-iron alloy was first subjected to sulfuric acid aging treatment, followed by water leaching to obtain a water leaching solution enriched with Ni and Fe, and a water leaching residue containing residual metals including Mo; the water leaching residue was then subjected to oxidative acid leaching treatment to obtain an acid leaching solution containing residual metals and an acid leaching residue.

2. The decomposition method of nickel-molybdenum-iron alloy as described in claim 1, characterized in that, The nickel-molybdenum-iron alloy is an alloy containing nickel, molybdenum, and iron; Preferably, the iron content is 10% to 80%, the molybdenum content is 5% to 40%, and the nickel content is 3% to 60% by weight.

3. The decomposition method of nickel-molybdenum-iron alloy as described in claim 1 or 2, characterized in that, The nickel-molybdenum-iron alloy was first crushed and mixed with water to obtain an alloy powder mixture; then it was mixed with sulfuric acid for sulfuric acid aging treatment. Preferably, the particle size of the nickel-molybdenum-iron alloy after crushing and grinding is less than 0.15 mm; Preferably, the amount of aging water added to the alloy powder mixture is 0.5% to 30% of the mass of the alloy powder; Preferably, the moisture content of the matured material in the matured process, including the water generated by the matured reaction, is 1% to 50%.

4. The decomposition method of nickel-molybdenum-iron alloy as described in claim 1, characterized in that, During the sulfuric acid aging process, the mass percentage concentration of the sulfuric acid solution is 70% to 98%. Depending on the state of the aging material, the temperature of the aging system is controlled between 50℃ and 200℃ using methods such as self-heating, external heating, and moisture absorption. Preferably, the mass ratio of sulfuric acid to nickel-molybdenum-iron alloy is 0.5 to 3; Preferably, the temperature during the sulfuric acid aging process is between 80℃ and 140℃; Preferably, the sulfuric acid aging time is 1 hour to 72 hours, and more preferably 2 hours to 24 hours.

5. The decomposition method of nickel-molybdenum-iron alloy as described in claim 1, characterized in that, The liquid-to-solid ratio during water immersion is 1:1 to 10:1 L / kg; Preferably, the immersion time is 20 min to 240 min; Preferably, the temperature during the immersion stage is 25℃~100℃.

6. The decomposition method of nickel-molybdenum-iron alloy as described in claim 1, characterized in that, The water-leached residue is placed in an acidic solution containing an oxidizing agent for oxidative acid leaching treatment.

7. The decomposition method of nickel-molybdenum-iron alloy as described in claim 6, characterized in that, The acid solution is an inorganic strong acid solution with a concentration of 1 mol / L to 8 mol / L; Preferably, the inorganic strong acid is at least one of hydrochloric acid, sulfuric acid, and nitric acid.

8. The decomposition method of nickel-molybdenum-iron alloy as described in claim 6, characterized in that, The oxidant is one or more of the following: nitric acid solution, sodium chlorate, chlorine, oxygen, and hydrogen peroxide solution.

9. The method for decomposing the nickel-molybdenum-iron alloy as described in any one of claims 6 to 8, characterized in that, The amount of acid and oxidant added during the oxidation and pickling process shall not be less than the theoretical reaction amount of each valuable metal in the alloy; Preferably, the weight ratio of acid solution to initial nickel-molybdenum-iron alloy is 0.5 to 4, more preferably 0.8 to 1.2; Preferably, the weight ratio of the oxidant to the initial nickel-molybdenum-iron alloy is 0.5 to 5:1, more preferably 1 to 2:1; Preferably, the temperature of the oxidative acid leaching process is 25℃~100℃; Preferably, the oxidative acid leaching time is 0.5h to 24h, and more preferably 1h to 8h.

10. The decomposition method of nickel-molybdenum-iron alloy as described in claim 1, characterized in that, Mo and other valuable metal elements are recovered from the acid leaching solution.

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