Selective separation and recovery process of nickel-cobalt-molybdenum waste based on hydrochloric acid system

Abstract

The invention belongs to the field of waste resource recovery and treatment, and provides a nickel-cobalt-molybdenum waste selective separation and recovery process based on a hydrochloric acid system.The recovery process comprises the steps that oxidation is carried out after acid leaching to remove iron, soluble fluoride salt is mixed in iron removal liquid to form fluoride precipitates, calcium and magnesium are effectively removed, and the recovery rate of nickel-cobalt-molybdenum waste is increased. Copper, manganese and cobalt are sequentially extracted, nickel-cobalt separation is achieved, molybdenum sulfide precipitates are generated through alkali metal sulfide, and the molybdenum element is efficiently recycled. In the recovery process, the iron removal rate is larger than 99.5%, the calcium and magnesium removal rate is larger than 99%, the molybdenum recovery rate is larger than 98%, the process is short, reagent consumption is reduced, and actual application and popularization are facilitated.

Description

Technical Field

[0001] The present invention belongs to the field of waste resource treatment and recycling, and relates to a selective separation and recycling process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system. Background Art

[0002] Nickel-cobalt-molybdenum waste, as an important secondary resource, is rich in high-value metals such as nickel, cobalt, manganese, and molybdenum, which have extremely high recycling value. With the development and progress of technology, the demand for these metals is increasing day by day. Especially in the fields of new energy vehicles, electronic devices, and aerospace, nickel, cobalt, and manganese are important components of battery materials, while molybdenum has a wide range of applications in electrode material doping, high-strength alloys, and catalyst manufacturing. However, there are many problems in traditional nickel-cobalt-molybdenum waste treatment technologies, which limit the effective recycling of these valuable metals.

[0003] Traditionally, for the extraction of nickel, cobalt, and manganese from nickel-cobalt-molybdenum waste, processes such as stepwise chemical precipitation or solvent extraction are usually adopted. These methods often require multiple steps of complex operations, including pretreatment, dissolution, separation, purification, and other links, with a long and time-consuming process. For example, in the process of extracting nickel, cobalt, and manganese using the chemical precipitation method, the waste needs to be appropriately acid-leached or dissolved in other forms first to make the target metals enter the solution state. Then, by adjusting the pH value of the solution, the selective precipitation of different metal ions is gradually achieved. This process not only requires precise control of reaction conditions such as temperature, concentration, and stirring speed, but also consumes a large amount of various chemical reagents to ensure the smooth progress of each step. In addition, due to possible interference between steps, the overall process efficiency is low, the production cost is increased, and a large amount of wastewater and waste residue may be generated, causing a negative impact on the environment.

[0004] Regarding the recovery of molybdenum, the existing technologies generally have the problem of low recovery rate, usually less than 80%, which means that a large amount of molybdenum resources cannot be effectively utilized. The low recovery rate of molybdenum is mainly attributed to the complex interaction between molybdenum and other impurity elements and its unique physical and chemical properties. Molybdenum is prone to form stable molybdates under acidic conditions, which makes it difficult to be directly separated from the solution by conventional precipitation or extraction methods. At the same time, the complexes formed between molybdenum and impurity elements such as calcium, magnesium, and iron further increase the difficulty of molybdenum recovery, reducing the purity and recovery efficiency of molybdenum.

[0005] In addition, the presence of impurities such as calcium, magnesium, and iron is also an important factor affecting the treatment effect of nickel-cobalt-molybdenum waste. In actual waste samples, elements such as calcium, magnesium, and iron often exist in the form of oxides or carbonates. They not only affect the dissolution process of target metals but also bring additional challenges in subsequent separation and purification stages. Therefore, how to effectively remove or inhibit the influence of these impurity elements has become the key to improving the recovery efficiency of valuable metals in nickel-cobalt-molybdenum waste.

[0006] In summary, although the existing nickel-cobalt-molybdenum waste treatment technologies can achieve the recovery of valuable metals to a certain extent, they face problems such as long extraction processes for nickel, cobalt, and manganese, low recovery rate of molybdenum elements, and severe interference from calcium, magnesium, and iron impurities. To overcome these problems, it is urgent to develop more efficient, environmentally friendly, and economical new technologies to meet the growing market demand and social development needs. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a selective separation and recovery process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system. The recovery process first removes iron by oxidation after acid leaching, then mixes soluble fluorides in the iron-removed solution to form fluoride precipitates to effectively remove calcium and magnesium, then extracts copper and manganese, and then cobalt in sequence to achieve nickel-cobalt separation. Finally, molybdenum sulfide precipitates are generated by using alkali metal sulfides to efficiently recover molybdenum elements. In the recovery process, the iron removal rate > 99.5%, the calcium and magnesium removal rate > 99%, the molybdenum recovery rate > 98%, and the process is relatively short, with reduced reagent consumption, which is conducive to practical popularization and application.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a selective separation and recovery process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system, including the following steps:

[0010] Mix hydrochloric acid with nickel-cobalt-molybdenum waste and perform acid leaching to obtain a leaching solution;

[0011] Mix an oxidant with the leaching solution and perform oxidation precipitation to obtain goethite precipitate and an iron-removed solution;

[0012] Mix soluble fluorides with the iron-removed solution and perform fluoride precipitation to obtain calcium fluoride and magnesium fluoride as well as a purified solution;

[0013] Perform extraction on the purified solution, first extract manganese and copper, and then extract cobalt to achieve the separation of cobalt and nickel, obtaining a molybdenum-containing solution;

[0014] Mix an alkali metal sulfide with the molybdenum-containing solution to generate molybdenum sulfide precipitate.

[0015] The recovery process provided by the present invention is a method for efficiently recovering valuable metals such as nickel, cobalt, and molybdenum from waste materials containing these valuable metals through hydrometallurgical technology. The source of the nickel-cobalt-molybdenum waste is not specifically limited. In addition to nickel, cobalt, and molybdenum, it also contains copper, manganese, calcium, magnesium, iron, etc. For iron, after acid leaching in the recovery process, an oxidant is mixed into the leaching solution to oxidize and precipitate iron, achieving efficient removal of iron. Then, soluble fluorides are used to form fluoride precipitates with calcium and magnesium, efficiently removing calcium and magnesium and preventing their influence on the separation and recovery of nickel, cobalt, manganese, and molybdenum. After extracting copper and manganese, and then cobalt, sequential separation and recovery of various valuable metals can be achieved. And by using alkali metal sulfides to form a precipitate with molybdenum to efficiently recover molybdenum, the recovery of each valuable metal is completed. In the recovery process, the iron removal rate > 99.5%, the calcium and magnesium removal rate > 99%, the molybdenum recovery rate > 98%, and the process flow is short, with reduced reagent consumption, which is conducive to practical popularization and application.

[0016] The present invention defines that the recovery process is based on a hydrochloric acid system because it has the following advantages: (1) Improving dissolution efficiency: Hydrochloric acid can effectively dissolve oxides and sulfides of nickel, cobalt, and molybdenum to form soluble chlorides, facilitating subsequent separation; (2) Promoting efficient removal of iron: In a hydrochloric acid medium, Fe 2+ is easily oxidized to Fe 3+ , forming goethite (FeO(OH)) precipitate, while in a sulfuric acid or nitric acid system, other iron precipitates (such as hematite) may be formed, with lower removal efficiency; (3) Effectively inhibiting impurity interference: In a hydrochloric acid system, high-concentration Cl - may compete with F - , but the solubility product of fluoride is extremely low (such as CaF2: Ksp≈3.9×10-11), and calcium and magnesium can still be effectively precipitated, that is, the interference of chloride ions on subsequent fluoride precipitation (CaF2, MgF2) is small, while a sulfuric acid system may introduce calcium sulfate precipitation, affecting the process; (4) Improving extraction compatibility: Common extractants (such as P204, Cyanex 272) have better selectivity and stability in an environment containing Cl - . For example, Cl - may change the complexation state of metal ions, making Co 2+ form [CoCl4] - in a Cl 2- environment, improving the selectivity of the extractant (such as Cyanex 272). (5) Facilitating molybdenum recovery: Cl - may interfere with molybdenum sulfide precipitation under alkaline conditions, but by precisely controlling the pH (7.8 - 8.2), side reactions can be inhibited to ensure the efficient formation of MoS2.

[0017] The following are the preferred technical solutions of the present invention, but not limitations on the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0018] As a preferred technical solution of the present invention, the concentration of the hydrochloric acid is 4 to 8 mol / L, such as 4 mol / L, 4.5 mol / L, 5 mol / L, 5.5 mol / L, 6 mol / L, 6.5 mol / L, 7 mol / L, 7.5 mol / L or 8 mol / L, etc., and is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0019] As a preferred technical solution of the present invention, the acid leaching includes first acid leaching and second acid leaching carried out in sequence.

[0020] Preferably, the liquid-solid mass ratio of hydrochloric acid to the nickel-cobalt-molybdenum waste in the first acid leaching is (3 to 5):1, such as 3:1, 3.3:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1 or 5:1, etc., and is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0021] Preferably, the temperature of the first acid leaching is 75 to 85 °C, such as 75 °C, 76 °C, 77 °C, 78 °C, 79 °C, 80 °C, 81 °C, 82 °C, 83 °C, 84 °C or 85 °C, etc., and the time is 1 to 3 h, such as 1 h, 1.3 h, 1.5 h, 1.8 h, 2 h, 2.3 h, 2.5 h, 2.8 h or 3 h, etc., and is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0022] Preferably, hydrochloric acid is added in the second acid leaching to make the pH = 0.8 to 1.2, such as 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15 or 1.2, etc., and is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0023] Preferably, the temperature of the second acid leaching is 85 to 95 °C, such as 85 °C, 86 °C, 87 °C, 88 °C, 89 °C, 90 °C, 91 °C, 92 °C, 93 °C, 94 °C or 95 °C, etc., and the time is 1 to 2 h, such as 1 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h or 2 h, etc., and is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0024] The present invention preferably realizes the efficient dissolution of nickel, cobalt, manganese and molybdenum (metal leaching rate > 95%) through two-stage leaching, which is also beneficial to inhibiting the formation of silica gel. Specifically, in the first-stage acid leaching, most metals can be quickly dissolved. However, excessive acid leads to too low local pH, promotes the formation of silica gel, hinders metal leaching, and high-temperature strong acid aggravates equipment corrosion. Therefore, the formation of silica gel (SiO2·nH2O) caused by excessive acid should be avoided to prevent the encapsulation of unreacted particles. The second-stage acid leaching can optimize the dissolution of residual metals and further inhibit the formation of silica gel.

[0025] As a preferred technical solution of the present invention, the oxidant includes hydrogen peroxide with a concentration of 25% - 35%, such as 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34% or 35%, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0026] Preferably, the molar ratio of the oxidant to the iron element in the leaching solution is (1 - 1.5):1, such as 1:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1, 1.3:1, 1.35:1, 1.4:1, 1.45:1 or 1.5:1, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0027] Preferably, the pH of the oxidation precipitation is 3 - 4, such as 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 or 4, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0028] As a preferred technical solution of the present invention, the soluble fluoride salt includes sodium fluoride.

[0029] As a preferred technical solution of the present invention, the fluoride precipitation includes first fluoride precipitation and second fluoride precipitation carried out in sequence.

[0030] Preferably, the molar ratio of the fluorine element in the soluble fluoride salt to the calcium element in the iron-removed solution in the first fluoride precipitation is (1 - 1.3):1, such as 1:1, 1.05:1, 1.08:1, 1.1:1, 1.13:1, 1.16:1, 1.2:1, 1.25:1, 1.28:1, 1.3:1, 1.35:1, 1.38:1, 1.4:1, 1.45:1, 1.48:1 or 1.5:1, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0031] Preferably, the molar ratio of fluorine element in the soluble fluoride salt in the second fluorination precipitation to magnesium element in the iron-removed solution is (1-1.1):1, such as 1:1, 1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1, 1.06:1, 1.07:1, 1.08:1, 1.09:1 or 1.1:1, etc., but not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0032] As a preferred technical solution of the present invention, the extractants used for extracting manganese and copper include P204 and / or P207.

[0033] In the recovery process of the present invention, extraction is carried out after fluorination precipitation, and a fluorination precipitation-extraction combined system can be established in industrial production. "Combined use" means seamlessly connecting the fluorination precipitation and extraction steps, which can specifically include: 1) Continuous solid-liquid separation: directly filtering after precipitation, and the purified liquid flows into the extraction system to reduce intermediate storage.

[0034] 2) Process parameter matching: controlling the residual amount of fluoride ions (such as <10mg / L) to avoid interfering with the performance of the extractant.

[0035] 3) Integrated equipment design: connecting the precipitation tank and the extraction tank in series to improve the treatment efficiency and reduce energy consumption.

[0036] Preferably, the extractants used for extracting manganese and copper include P204 and P207 with a volume ratio of (2-4):1. But not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0037] Preferably, the extractant used for extracting cobalt includes Cyanex 272.

[0038] Preferably, the pH during cobalt extraction is 4.8-5.2, such as 4.8, 4.85, 4.9, 4.95, 5, 5.05, 5.1, 5.15 or 5.2, etc.

[0039] As a preferred technical solution of the present invention, the pH of the molybdenum-containing solution is pre-adjusted to 7.8-8.2, such as 7.8, 7.84, 7.88, 7.9, 7.92, 7.95, 7.98, 8, 8.02, 8.06, 8.1, 8.13, 8.15 or 8.2, etc., and then mixed with the alkali metal sulfide. But not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0040] As a preferred technical solution of the present invention, the alkali metal sulfide includes sodium sulfide.

[0041] Preferably, the molar ratio of sulfur element in the alkali metal sulfide to molybdenum element in the molybdenum-containing solution is (1-1.1):1, such as 1:1, 1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1, 1.06:1, 1.07:1, 1.08:1, 1.09:1 or 1.1:1, etc. For example, but not limited to the listed values, other unlisted values within the above numerical range are equally applicable.

[0042] As a preferred technical solution of the present invention, after the molybdenum sulfide precipitate is dissolved in ammonia water and then evaporated and crystallized, ammonium molybdate is obtained.

[0043] The present invention uses alkali metal sulfide to precipitate molybdenum, so that the recovery rate of molybdenum can be increased from 85% of the existing traditional process to more than 98%, and can reach 98.5%. It avoids the SO2 pollution problem of the traditional sulfide roasting process. The obtained molybdenum sulfide can be treated by ammonia dissolution and crystallization to prepare ammonium molybdate, improving the added value. In actual process production, a combined system of sulfide precipitation-ammonia dissolution and crystallization can be established.

[0044] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0045] In the recovery process of the present invention, after acid leaching, iron is first oxidized and removed, and then soluble fluoride salts are mixed in the iron-removed solution to form fluoride precipitates, effectively removing calcium and magnesium. Then copper, manganese, and cobalt are extracted in turn to achieve nickel-cobalt separation. Finally, alkali metal sulfide is used to generate molybdenum sulfide precipitate to efficiently recover molybdenum element. In the recovery process, the iron removal rate > 99.5%, the calcium and magnesium removal rate > 99%, the molybdenum recovery rate > 98%, and the process flow is short, the reagent consumption is reduced, which is conducive to practical popularization and application. Specific Embodiments

[0046] The technical solutions of the present invention will be further described below through specific embodiments.

[0047] Those skilled in the art should understand that the embodiments are only helpful for understanding the present invention and should not be regarded as specific limitations of the present invention.

[0048] Example 1

[0049] This example provides a selective separation and recovery process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system. The recovery process includes the following steps:

[0050] (1) Prepare nickel-cobalt-molybdenum waste, and the mass percentage content of the contained metal elements is shown in Table 1.

[0051] Table 1

[0052] Co Ni Mn Cu Ca Mg Fe Mo 5.5050％ 23.9604％ 9.3861％ 0.0258％ 1.1706％ 1.8094％ 4.3962％ 3.9400％

[0053] Prepare 6 mol / L hydrochloric acid, mix it by feeding materials according to the liquid-solid mass ratio of hydrochloric acid to nickel-cobalt-molybdenum waste of 4:1, conduct the first acid leaching at 80 °C for 2 h, then supplement hydrochloric acid until pH = 1.0, and conduct the second acid leaching at 90 °C for 1.5 h to obtain a leaching solution;

[0054] (2) Add hydrogen peroxide with a concentration of 30% to the leaching solution, control the dosage according to the molar ratio of hydrogen peroxide to iron element in the leaching solution of 1.2:1, and conduct oxidation precipitation at pH = 3.5 to generate goethite precipitation, obtaining an iron-removed solution;

[0055] (3) Prepare soluble fluoride salt sodium fluoride, add sodium fluoride to the iron-removed solution in two times. The amount added for the first time is controlled such that the molar ratio of fluorine element in sodium fluoride to calcium element in the iron-removed solution is 1.1:1 for the first fluorination precipitation; then the amount added for the second time is controlled such that the molar ratio of fluorine element in sodium fluoride to magnesium element in the iron-removed solution is 1.05:1 for the second fluorination precipitation; calcium fluoride and magnesium fluoride, as well as a purified solution, are obtained;

[0056] (4) Extract the purified solution. First, extract copper and manganese with P204 + P507 (volume ratio 3:1), after adjusting pH = 5.0, use Cyanex 272 to selectively extract cobalt to achieve cobalt-nickel separation, obtaining a molybdenum-containing solution;

[0057] (5) Acidify the molybdenum-containing solution to pH = 8, then mix it with alkali metal sulfide sodium sulfide to generate molybdenum sulfide precipitation, and prepare ammonium molybdate through ammonia water dissolution and evaporation crystallization.

[0058] Example 2

[0059] This example provides a selective separation and recovery process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system. In step (1) of the recovery process, the liquid-solid mass ratio of hydrochloric acid to nickel-cobalt-molybdenum waste in the first acid leaching is adjusted from 4:1 to 2:1. Except for the above, other conditions are exactly the same as those in Example 1.

[0060] Example 3

[0061] This example provides a selective separation and recovery process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system. In step (1) of the recovery process, the liquid-solid mass ratio of hydrochloric acid to nickel-cobalt-molybdenum waste in the first acid leaching is adjusted from 4:1 to 3:1. Except for the above, other conditions are exactly the same as those in Example 1.

[0062] Example 4

[0063] This embodiment provides a selective separation and recovery process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system. In step (1) of the recovery process, the liquid-solid mass ratio of hydrochloric acid to nickel-cobalt-molybdenum waste in the first acid leaching is adjusted from 4:1 to 5:1. Except for the above, other conditions are exactly the same as those in Example 1.

[0064] Example 5

[0065] This embodiment provides a selective separation and recovery process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system. In step (1) of the recovery process, the liquid-solid mass ratio of hydrochloric acid to nickel-cobalt-molybdenum waste in the first acid leaching is adjusted from 4:1 to 6:1. Except for the above, other conditions are exactly the same as those in Example 1.

[0066] Example 6

[0067] This embodiment provides a selective separation and recovery process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system. In step (1) of the recovery process, all the hydrochloric acid is added at once and mixed. First, acid leaching is carried out at 80 °C for 2 h, and then acid leaching is carried out at 90 °C for 1.5 h. Except for the above, other conditions are exactly the same as those in Example 1.

[0068] Example 7

[0069] This embodiment provides a selective separation and recovery process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system. In step (3) of the recovery process, all sodium fluoride is put in at once and mixed. Except for the above, other conditions are exactly the same as those in Example 1.

[0070] Comparative Example 1

[0071] This comparative example provides a selective separation and recovery process for nickel-cobalt-molybdenum waste based on a hydrochloric acid system. The recovery process does not carry out step (3). Except for the above, other conditions are exactly the same as those in Example 1.

[0072] During the monitoring and supervision of the recovery process in the examples, after acid leaching, the content of elements in the leaching solution is tested and the leaching rate is calculated; after removing iron, calcium, and magnesium, the content of elements in the purified solution is tested and the residue amount is calculated; after extraction, the purity of the extracted cobalt and the separation coefficient of nickel and cobalt are tested and calculated; the molybdenum product ammonium molybdate obtained by recovery is tested to obtain the purity; the above data are listed in Table 2.

[0073] Table 2

[0074]

[0075] It can be seen from the above that in the recovery process of the present invention, iron is removed by oxidation after acid leaching, and then soluble fluoride salts are mixed in the iron-removed solution to form fluoride precipitates, effectively removing calcium and magnesium. Then, copper, manganese, and cobalt are extracted in sequence to achieve the separation of nickel and cobalt. Finally, molybdenum sulfide precipitates are generated by using alkali metal sulfides to efficiently recover molybdenum elements. In the said recovery process, the iron removal rate > 99.5%, the calcium and magnesium removal rate > 99%, the molybdenum recovery rate > 98%, and the process flow is short, with reduced reagent consumption, which is conducive to practical popularization and application.

[0076] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0077] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any appropriate way. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0078] In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A selective separation and recovery process for nickel-cobalt-molybdenum waste based on hydrochloric acid system, characterized in that, It includes the following steps: Mix hydrochloric acid with nickel-cobalt-molybdenum waste, carry out acid leaching to obtain a leaching solution; Mix an oxidant with the leaching solution, carry out oxidation precipitation to obtain goethite precipitation and iron-removed solution; Mix soluble fluoride salt with the iron-removed solution, carry out fluoride precipitation to obtain calcium fluoride, magnesium fluoride and a purified solution; Extract the purified solution, first extract manganese and copper, and then extract cobalt to separate cobalt from nickel to obtain a molybdenum-containing solution; Mix an alkali metal sulfide with the molybdenum-containing solution to form molybdenum sulfide precipitation.

2. The selective separation and recovery process of nickel-cobalt-molybdenum waste based on hydrochloric acid system according to claim 1, characterized in that, The concentration of the hydrochloric acid is 4-8 mol / L.

3. The selective separation and recovery process of nickel-cobalt-molybdenum waste based on hydrochloric acid system according to claim 1, wherein, The acid leaching includes first acid leaching and second acid leaching carried out in sequence; Preferably, the liquid-solid mass ratio of hydrochloric acid to the nickel-cobalt-molybdenum waste in the first acid leaching is (3-5):1; Preferably, the temperature of the first acid leaching is 75-85 °C and the time is 1-3 h; Preferably, hydrochloric acid is added to the second acid leaching to adjust the pH to 0.8-1.2; Preferably, the temperature of the second acid leaching is 85-95 °C and the time is 1-2 h.

4. The selective separation and recovery process of nickel-cobalt-molybdenum waste based on hydrochloric acid system according to claim 1, characterized in that, The oxidant includes hydrogen peroxide with a concentration of 25%-35%; Preferably, the molar ratio of the oxidant to the iron element in the leaching solution is (1-1.5):1; Preferably, the pH of the oxidation precipitation is 3-4.

5. The selective separation and recovery process of nickel-cobalt-molybdenum waste based on hydrochloric acid system according to claim 1, characterized in that, The soluble fluoride salt includes sodium fluoride.

6. The selective separation and recovery process of nickel-cobalt-molybdenum waste based on hydrochloric acid system according to claim 1, characterized in that, The fluoride precipitation includes first fluoride precipitation and second fluoride precipitation carried out in sequence; Preferably, the molar ratio of the fluorine element in the soluble fluoride salt to the calcium element in the iron-removed solution in the first fluoride precipitation is (1-1.3):1; Preferably, the molar ratio of the fluorine element in the soluble fluoride salt to the magnesium element in the iron-removed solution in the second fluoride precipitation is (1-1.1):

1.

7. The selective separation and recovery process of nickel-cobalt-molybdenum waste based on hydrochloric acid system according to claim 1, characterized in that, The extractant used for extracting manganese and copper includes P204 and / or P207; Preferably, the extractant used for extracting manganese and copper includes P204 and P207 with a volume ratio of (2-4):1; Preferably, the extractant used for extracting cobalt includes Cyanex 272.

8. The selective separation and recovery process of nickel-cobalt-molybdenum waste based on hydrochloric acid system according to claim 1, characterized in that, The pH of the molybdenum-containing solution is pre-adjusted to 7.8-8.2 and then mixed with the alkali metal sulfide.

9. The selective separation and recovery process of nickel-cobalt-molybdenum waste based on hydrochloric acid system according to claim 1, characterized in that, The alkali metal sulfide includes sodium sulfide; Preferably, the molar ratio of the sulfur element in the alkali metal sulfide to the molybdenum element in the molybdenum-containing solution is (1-1.1):

1.

10. The selective separation and recovery process of nickel-cobalt-molybdenum waste based on hydrochloric acid system according to claim 1, characterized in that, After the molybdenum sulfide precipitation is dissolved in ammonia water and then evaporated and crystallized, ammonium molybdate is obtained.

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