A method for resource recovery of tungsten tailings

Abstract

This invention provides a method for the resource recovery of tungsten extraction tailings. The method includes the following steps: slurrying the tungsten extraction tailings with water and then mixing it with concentrated sulfuric acid, followed by pre-leaching to obtain an acidic slurry; subjecting the acidic slurry to a first oxygen pressure leaching treatment to obtain an enriched acidic solution and leaching residue; subjecting the leaching residue to a first post-treatment to obtain tantalum- and niobium-enriched tailings; adjusting the enriched acidic solution to a first pH and heating it to obtain a reaction solution; subjecting the reaction solution to a second oxygen pressure leaching treatment to obtain a leaching slurry; adjusting the leaching slurry to a second pH and performing a blending reaction, separating the solid and liquid to obtain a nickel- and cobalt-rich salt solution and a blending residue; subjecting the blending residue to a second post-treatment to obtain tungsten-enriched slag. This invention utilizes multi-stage leaching and blending reactions on tungsten extraction tailings to obtain tantalum- and niobium-enriched tailings, a nickel- and cobalt-rich salt solution, and tungsten-enriched slag, achieving comprehensive recovery of tungsten extraction tailings.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling technology and relates to a method for the resource recycling of tungsten tailings. Background Technology

[0002] In the special alloy industry, a large amount of grinding waste is generated. Our company uses an alkaline leaching process to extract tungsten, and the resulting tungsten extraction tailings contain valuable metals such as cobalt and nickel, which are raw materials for preparing battery-grade ternary precursors. They also contain trace amounts of high-value metals such as tantalum, niobium, and tungsten. However, the high content of impurities such as Fe and Cr in the tailings, along with the low grade of valuable metals like cobalt and nickel, makes the extraction and separation of these valuable metals extremely difficult. Therefore, how to comprehensively utilize tungsten extraction tailings for high-value purposes is an important measure in green metallurgical technology.

[0003] Currently, the technical challenges in treating this tailings are: low leaching recovery rates of Co and Ni, high content of impurities such as Fe and Cr that are difficult to remove, and the loss of valuable metals due to entrainment caused by conventional impurity removal methods, making it difficult to enrich trace amounts of valuable metals. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a resource-based recycling method for tungsten extraction tailings. The present invention involves multi-stage leaching and blending reactions of the tungsten extraction tailings to obtain tailings enriched with tantalum and niobium, a nickel-cobalt salt solution, and tungsten-enriched tailings, thereby achieving comprehensive recycling of tungsten extraction tailings.

[0005] To achieve this objective, the present invention adopts the following technical solution: This invention provides a method for the resource recovery of tungsten tailings, the method comprising the following steps: The tungsten tailings were slurried with water and then mixed with concentrated sulfuric acid. After pre-leaching, an acidic slurry was obtained. The acidic slurry is subjected to a first oxygen pressure leaching treatment to obtain an acid-enriched solution and leaching residue. The leaching residue is then subjected to a first post-treatment to obtain tailings enriched with tantalum and niobium. The acidic solution was adjusted to a first pH and heated to obtain a reaction solution. The reaction solution was then subjected to a second oxygen pressure leaching treatment to obtain a leachate. The leaching slurry was adjusted to a second pH for a blending reaction. Solid-liquid separation was performed to obtain a nickel-cobalt salt-rich solution and a blending residue. The blending residue was then subjected to a second post-treatment to obtain enriched tungsten slag.

[0006] In the resource recovery method for tungsten tailings described in this invention, pre-leaching with concentrated sulfuric acid can initially dissolve alkaline oxides and some impurities such as iron and aluminum in the tailings, reducing acid consumption and impurity load in subsequent oxygen pressure leaching. Simultaneously, it activates the surface of the ore particles, facilitating the release of the target metal. During the first oxygen pressure leaching process, low-valence metals are oxidized to high-valence states. Ta and Nb typically exist stably in the slag as oxides under acidic conditions. Most Ni, Co, and W enter the solution, while Ta and Nb remain in the slag, achieving preferential separation and facilitating the subsequent separate recovery of tantalum and niobium concentrate. After adjusting the pH of the acidic solution, some impurities hydrolyze and precipitate. The second oxygen pressure leaching process further enhances the leaching of valuable metals such as Ni, Co, and W and effectively removes high-content impurities such as Fe and Cr, effectively preventing the enrichment of Fe and Cr impurities. Subsequently, by adjusting the reaction and utilizing the differences in the hydrolysis and precipitation characteristics of different metal ions at different pH levels, Ni and Co are retained in the solution. The resulting nickel-cobalt salt solution can be used to prepare high-purity nickel sulfate and cobalt sulfate, while tungsten selectively precipitates into the slag, thus achieving efficient separation of Ni / Co and W.

[0007] Preferably, the liquid-to-solid mass ratio of the slurry is (1.5~2.5):1, for example: 1.5:1, 1.8:1, 2:1, 2.2:1 or 2.5:1, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0008] Preferably, the pulping time is 1h to 3h, for example: 1h, 1.5h, 2h, 2.5h or 3h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0009] Preferably, the pH of the pre-leaching treatment is 0.4 to 0.6, for example: 0.4, 0.45, 0.5, 0.55 or 0.6, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0010] Preferably, the temperature of the pre-leaching treatment is 70℃~90℃, for example: 70℃, 75℃, 80℃, 85℃ or 90℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0011] Preferably, the pre-leaching treatment time is 1h to 3h, for example: 1h, 1.5h, 2h, 2.5h or 3h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0012] Preferably, the flow rate of the acidic slurry in the first oxygen pressure leaching treatment is 15 m³ / s. 3 / h~25m 3 / h, for example: 15m 3 / h、18m3 / h, 20m 3 / h、22m 3 / h or 25m 3 / h, etc., are not limited to the listed values; other unlisted values ​​within this range also apply.

[0013] Preferably, the oxygen flow rate of the first oxygen pressure leaching treatment is 200 Nm³. 3 / h~300Nm 3 / h.

[0014] Preferably, the temperature of the first oxygen pressure leaching treatment is 120℃~180℃, for example: 120℃, 140℃, 150℃, 160℃ or 180℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0015] Preferably, the pressure of the first oxygen pressure leaching treatment is 0.5MPa to 0.8MPa, for example: 0.5MPa, 0.55MPa, 0.6MPa, 0.7MPa or 0.8MPa, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] Preferably, the oxygen partial pressure of the first oxygen pressure leaching treatment is 20% to 25%, for example: 20%, 21%, 22%, 23%, 24% or 25%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] Preferably, after the first oxygen pressure leaching treatment, flash evaporation, solid-liquid separation, and cyclic leaching are performed.

[0018] Preferably, the first post-treatment includes hydrothermal washing of the leaching residue, followed by sequential water washing, backflushing and pressing to obtain tailings enriched with tantalum and niobium and water washing liquid.

[0019] Preferably, the solid-liquid mass ratio of the hydrothermal washing treatment is (0.8~1.1):1, for example: 0.8:1, 0.85:1, 0.9:1, 1:1 or 1.1:1, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] Preferably, the temperature of the hydrothermal washing treatment is 80℃~90℃, for example: 80℃, 82℃, 85℃, 88℃ or 90℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Preferably, the reaction time of the hydrothermal washing treatment is 1h to 3h, for example: 1h, 1.5h, 2h, 2.5h or 3h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0022] Preferably, the washing liquid is reused for slurrying of tungsten tailings.

[0023] Preferably, the adjusting agent for adjusting the acidic solution to the first pH includes liquid alkali and / or lime milk.

[0024] Preferably, the first pH is 2.8 to 3.2, for example: 2.8, 2.9, 3, 3.1 or 3.2, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] Preferably, the temperature of the heating reaction is 60℃~80℃, for example: 60℃, 65℃, 70℃, 75℃ or 80℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, the heating reaction time is 0.5h to 1.5h, for example: 0.5h, 0.8h, 1h, 1.2h or 1.5h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the temperature of the second oxygen pressure leaching treatment is 150°C to 180°C, for example: 150°C, 155°C, 160°C, 170°C or 180°C, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the pressure of the second oxygen pressure leaching treatment is 0.6MPa to 0.8MPa, for example: 0.6MPa, 0.65MPa, 0.7MPa, 0.75MPa or 0.8MPa, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] Preferably, the oxygen partial pressure of the second oxygen pressure leaching treatment is 15% to 25%, for example: 15%, 18%, 20%, 22% or 25%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] Preferably, the second oxygen pressure leaching treatment time is 3h to 5h, for example: 3h, 3.5h, 4h, 4.5h or 5h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0031] Preferably, the second oxygen pressure leaching treatment is followed by flash evaporation and cooling.

[0032] Preferably, the adjusting agent for adjusting the leachate to the second pH includes liquid alkali.

[0033] Preferably, the second pH is 4.5 to 5, for example: 4.5, 4.6, 4.8, 4.9 or 5, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] Preferably, the temperature of the formulation reaction is 80℃~90℃, for example: 80℃, 82℃, 85℃, 88℃ or 90℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the reaction time is 3h to 5h, for example: 3h, 3.5h, 4h, 4.5h or 5h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the second post-treatment includes mixing the blended slag with concentrated sulfuric acid for acid washing, followed by water washing, backflushing, and pressing to obtain enriched tungsten slag.

[0037] Preferably, the solid-liquid mass ratio of the blending residue to concentrated sulfuric acid is (0.8~1):1, for example: 0.8:1, 0.85:1, 0.9:1, 0.95:1 or 1:1, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] Preferably, the pH of the acid washing reaction is 1 to 1.5, for example: 1, 1.1, 1.2, 1.3, 1.4 or 1.5, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] Preferably, the temperature of the pickling reaction is 60℃~80℃, for example: 60℃, 65℃, 70℃, 75℃ or 80℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Preferably, the pickling reaction time is 1h to 3h, for example: 1h, 1.5h, 2h, 2.5h or 3h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0042] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention performs multi-stage leaching and blending reaction on tungsten tailings to obtain tailings enriched with tantalum and niobium, nickel-cobalt salt solution and tungsten-enriched slag, thus realizing the comprehensive recovery of tungsten tailings.

[0043] (2) The resource recovery method of tungsten tailings described in this invention achieves the enrichment of tantalum and niobium in tungsten tailings, resulting in a low impurity content in the enriched tungsten tailings, and the recovered nickel-cobalt rich solution has a low impurity content, which can be directly used to prepare nickel-cobalt products. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the process flow for the resource recovery method of tungsten tailings as described in the embodiments of the present invention. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] The "range" disclosed in this invention can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0047] In this invention, "a combination of at least two" refers to a quantity greater than or equal to two, unless otherwise specified. For example, "any combination of one or at least two" means one or more or more items. It can be understood that when referring to "a combination of at least two," it refers to any suitable combination of multiple items, that is, a combination of "at least two" items carried out in a manner that does not conflict with and enables the implementation of this invention.

[0048] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0049] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0050] Those skilled in the art will understand that the order in which the steps are written in the methods of the various embodiments does not imply a strict execution order. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), meaning that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0051] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0052] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0053] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0054] In this invention, "optional" means that something is optional, that is, it refers to any one of the two parallel solutions of "having" or "not having". If there are multiple "optional" options in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, then each "optional" option is independent.

[0055] In this invention, "room temperature" generally refers to 4℃~35℃, and can refer to 20℃±5℃. In some embodiments of this invention, room temperature refers to 20℃~30℃.

[0056] The concentrated sulfuric acid used in the embodiments and comparative examples of this invention is 98% concentrated sulfuric acid by mass.

[0057] Example 1 This embodiment provides a method for the resource recovery of tungsten tailings, and the process flow diagram of the resource recovery method is shown below. Figure 1 As shown, the method includes the following steps: The tungsten tailings were slurried and ball-milled with water at a solid-liquid mass ratio of 2:1 for 2 hours, then mixed with concentrated sulfuric acid. The pH was controlled at 0.5, and the mixture was pre-leached at 80℃ for 2 hours to obtain an acidic slurry. The acidic slurry was prepared at a flow rate of 20 m³ / h. 3 / h pumped into the high-pressure reactor, with oxygen flow controlled at 250Nm 3The process involves controlling the temperature at 150℃ and the pressure at 0.6MPa, with the oxygen partial pressure controlled at 20%, to perform the first oxygen pressure leaching treatment. After flash evaporation, solid-liquid separation, and circulating leaching, an acid-rich solution and leaching residue are obtained. The leaching residue is washed at a solid-liquid ratio of 0.9:1, heated to 85℃, and reacted for 2 hours before solid-liquid separation. The residue is then subjected to a process of water washing for 10 minutes, backflushing for 5 minutes, and pressing for 30 seconds on a filter press to obtain a tailings enriched with tantalum and niobium. The pH of the enriched acidic solution was adjusted to 3 using liquid alkali, and the reaction was carried out at 70°C for 1 hour to obtain a reaction solution. The reaction solution was then subjected to a second oxygen pressure leaching treatment at 160°C, 0.7 MPa, and 20% oxygen partial pressure for 4 hours. After flash evaporation and cooling, the leachate was obtained. The pH of the leaching slurry was adjusted to 4.8 using liquid alkali, and the mixture was reacted at 85°C for 4 hours. Solid-liquid separation was performed to obtain a nickel-cobalt salt-rich solution and a mixture residue (the nickel-cobalt salt-rich solution was used for nickel and cobalt extraction). The mixture residue was then reacted with concentrated sulfuric acid at a solid-liquid ratio of 0.9:1 to control the pH at 1.2. The mixture was kept at 70°C for 2 hours, and then solid-liquid separation was performed. The mixture was then subjected to a process of washing with water for 10 minutes, backflushing for 5 minutes, and pressing for 30 seconds on a filter press to obtain enriched tungsten slag.

[0058] Example 2 This embodiment provides a method for the resource recovery of tungsten tailings, and the process flow diagram of the resource recovery method is shown below. Figure 1 As shown, the method includes the following steps: The tungsten tailings were slurried and ball-milled with water at a solid-liquid mass ratio of 1.5:1 for 3 hours, then mixed with concentrated sulfuric acid. The pH was controlled at 0.6, and the mixture was pre-leached at 70°C for 3 hours to obtain an acidic slurry. The acidic slurry was prepared at a flow rate of 15 m³ / h. 3 / h pumped into the high-pressure reactor, controlling the oxygen flow rate at 300Nm 3 The process involves controlling the temperature at 120℃ and the pressure at 0.5MPa, with the oxygen partial pressure controlled at 20%, to perform the first oxygen pressure leaching treatment. After flash evaporation, solid-liquid separation, and circulating leaching, an acid-rich solution and leaching residue are obtained. The leaching residue is washed at a solid-liquid ratio of 0.8:1 and heated to 80℃. After reacting for 3 hours, solid-liquid separation is performed. The residue is then subjected to a process of water washing for 10 minutes, backflushing for 5 minutes, and pressing for 30 seconds on a filter press to obtain a tailings enriched with tantalum and niobium. The pH of the enriched acidic solution was adjusted to 2.8 using lime milk, and the reaction was carried out at 60°C for 1.5 hours to obtain a reaction solution. The reaction solution was then subjected to a second oxygen pressure leaching treatment at 150°C, 0.6 MPa, and 25% oxygen partial pressure for 5 hours. After flash evaporation and cooling, the leachate was obtained. The pH of the leaching slurry was adjusted to 4.5 using liquid alkali, and the mixture was prepared and reacted at 80°C for 5 hours. Solid-liquid separation was performed to obtain a nickel-cobalt salt-rich solution and a prepared residue (the nickel-cobalt salt-rich solution was used for nickel and cobalt extraction). The prepared residue was prepared at a solid-liquid ratio of 0.8:1, and concentrated sulfuric acid was added to control the pH to 1.5. The mixture was kept at 60°C and reacted for 3 hours before solid-liquid separation. The slag was then enriched by washing with water for 10 minutes, backflushing for 5 minutes, and pressing for 30 seconds on a filter press.

[0059] Example 3 This embodiment provides a method for the resource recovery of tungsten tailings, and the process flow diagram of the resource recovery method is shown below. Figure 1 As shown, the method includes the following steps: The tungsten tailings were slurried and ball-milled with water at a solid-liquid mass ratio of 2.5:1 for 1 hour, then mixed with concentrated sulfuric acid. The pH was controlled at 0.4, and the mixture was pre-leached at 90°C for 1 hour to obtain an acidic slurry. The acidic slurry was prepared at a flow rate of 25 m³ / h. 3 / h pumped into the high-pressure reactor, with oxygen flow controlled at 200Nm 3 The process involves controlling the temperature at 180℃ and the pressure at 0.8MPa, with the oxygen partial pressure controlled at 15%, to perform the first oxygen pressure leaching treatment. After flash evaporation, solid-liquid separation, and circulating leaching, an acid-rich solution and leaching residue are obtained. The leaching residue is washed at a solid-liquid ratio of 1.1:1, heated to 90℃, and reacted for 1 hour before solid-liquid separation. The residue is then subjected to a process of water washing for 10 minutes, backflushing for 5 minutes, and pressing for 30 seconds on a filter press to obtain a tailings enriched with tantalum and niobium. The pH of the enriched acidic solution was adjusted to 3.2 using liquid alkali, and the reaction was carried out at 80°C for 0.5 h to obtain a reaction solution. The reaction solution was subjected to a second oxygen pressure leaching treatment at 180°C, 0.8 MPa and oxygen partial pressure of 15% for 3 h, and then flash evaporation and cooling were used to obtain the leachate. The pH of the leaching slurry was adjusted to 5 using liquid alkali, and the mixture was prepared and reacted at 90℃ for 3 hours. Solid-liquid separation was performed to obtain a nickel-cobalt salt-rich solution and a prepared residue (the nickel-cobalt salt-rich solution was used for nickel and cobalt extraction). The prepared residue was prepared at a solid-liquid ratio of 1:1, and concentrated sulfuric acid was added to control the pH to 1. The mixture was kept at 80℃ and reacted for 1 hour before solid-liquid separation. The tungsten-enriched slag was obtained by washing with water for 10 minutes, backflushing for 5 minutes, and pressing for 30 seconds on a filter press.

[0060] Example 4 The only difference between this embodiment and Embodiment 1 is that the pressure of the first oxygen pressure leaching treatment is 0.4 MPa, while the other conditions and parameters are exactly the same as in Embodiment 1.

[0061] Example 5 The only difference between this embodiment and Embodiment 1 is that the pressure of the first oxygen pressure leaching treatment is 0.9 MPa, while the other conditions and parameters are exactly the same as in Embodiment 1.

[0062] Example 6 The only difference between this embodiment and Embodiment 1 is that the pressure of the second oxygen pressure leaching treatment is 0.5 MPa, while the other conditions and parameters are exactly the same as in Embodiment 1.

[0063] Example 7 The only difference between this embodiment and Embodiment 1 is that the pressure of the second oxygen pressure leaching treatment is 0.9 MPa, while the other conditions and parameters are exactly the same as in Embodiment 1.

[0064] Comparative Example 1 The only difference between this comparative example and Example 1 is that no pre-leaching treatment is performed; all other conditions and parameters are exactly the same as in Example 1.

[0065] Comparative Example 2 The only difference between this comparative example and Example 1 is that the first oxygen pressure leaching treatment is not performed; all other conditions and parameters are exactly the same as in Example 1.

[0066] Performance testing: The metal content in tantalum-niobium enriched tailings, tungsten enriched slag, and nickel-cobalt rich salt solutions was obtained by testing the examples and comparative examples. The test results are shown in Table 1. Table 1 As shown in Table 1, and as obtained from Examples 1-3, the resource recovery method for tungsten tailings described in this invention yields tantalum- and niobium-rich tailings with a tantalum content of over 0.942% and a niobium content of over 0.386%. The enriched tungsten slag contains over 9.1% tungsten, less than 0.167% tantalum, and less than 0.03% niobium. The resulting nickel-cobalt salt solution has a cobalt content of over 31.57 g / L, a nickel content of over 7.84 g / L, an iron content of less than 0.18 g / L, and a chromium content of less than 0.02 g / L. This method achieves the enrichment of tantalum and niobium in the tungsten tailings, resulting in a low impurity content in the enriched tungsten slag and a low impurity content in the recovered nickel-cobalt solution. The nickel-cobalt solution can be directly used to prepare nickel-cobalt products.

[0067] A comparison of Examples 1 and 4-5 shows that in the resource recovery method for tungsten tailings described in this invention, the pressure of the first oxygen pressure leaching treatment affects the recovery effect. Controlling the pressure of the first oxygen pressure leaching treatment at 0.5MPa~0.8MPa results in a better recovery effect. If the pressure of the first oxygen pressure leaching treatment is too high, the leaching rate of cobalt and nickel and the enrichment effect of tantalum, niobium and tungsten are not significantly improved, and excessive pressure poses safety hazards such as flash explosion. If the pressure of the first oxygen pressure leaching treatment is too low, the leaching rate of cobalt and nickel decreases, resulting in a decrease in the tantalum and niobium content of the first-stage leaching residue and a significant decrease in the concentration of Co and Ni in nickel-rich cobalt salts.

[0068] A comparison of Examples 1 and 6-7 shows that in the resource recovery method for tungsten tailings described in this invention, the pressure of the second oxygen pressure leaching treatment affects the recovery effect. Controlling the pressure of the second oxygen pressure leaching treatment at 0.6 MPa to 0.8 MPa yields better recovery results. If the pressure of the second oxygen pressure leaching treatment is too high, the removal rate of Fe and Cr increases, the Fe and Cr content in the tungsten slag relatively increases, and the W grade of the enriched tungsten slag slightly decreases. Furthermore, excessive pressure poses safety hazards such as flash explosions. If the pressure of the second oxygen pressure leaching treatment is too low, Fe and Cr are not completely removed, resulting in Fe and Cr contents in the nickel-cobalt salt solution reaching as high as 342.6 mg / L and 32.6 mg / L, respectively. The W recovery rate also decreases simultaneously, and the W grade in the tungsten slag decreases.

[0069] As can be seen from the comparison between Example 1 and Comparative Example 1, in the resource recovery method of tungsten tailings described in this invention, the pre-leaching with concentrated sulfuric acid can initially dissolve alkaline oxides, some iron, aluminum and other impurities in the tailings, reduce the acid consumption and impurity load of subsequent oxygen pressure leaching, and activate the surface of ore particles, which is conducive to the release of the target metal.

[0070] By comparing Example 1 and Comparative Example 2, it can be seen that in the first oxygen pressure leaching process of the present invention, low-valence metals are oxidized to high-valence metals. Ta and Nb usually exist stably in the slag in the form of oxides under acidic conditions. Most of Ni, Co, W, etc. enter the solution, while Ta and Nb remain in the slag, achieving preferential separation and facilitating the subsequent separate recovery of tantalum and niobium concentrate.

[0071] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for the resource recovery of tungsten tailings, characterized in that, The method includes the following steps: The tungsten tailings were slurried with water and then mixed with concentrated sulfuric acid. After pre-leaching, an acidic slurry was obtained. The acidic slurry is subjected to a first oxygen pressure leaching treatment to obtain an acid-enriched solution and leaching residue. The leaching residue is then subjected to a first post-treatment to obtain tailings enriched with tantalum and niobium. The acidic solution was adjusted to a first pH and heated to obtain a reaction solution. The reaction solution was then subjected to a second oxygen pressure leaching treatment to obtain a leachate. The leaching slurry was adjusted to a second pH for a blending reaction. Solid-liquid separation was performed to obtain a nickel-cobalt salt-rich solution and a blending residue. The blending residue was then subjected to a second post-treatment to obtain enriched tungsten slag.

2. The recycling method as described in claim 1, characterized in that, The liquid-to-solid mass ratio of the slurry is (1.5~2.5):1; Preferably, the pulping time is 1 hour to 3 hours; Preferably, the pH of the pre-leaching treatment is 0.4 to 0.6; Preferably, the temperature of the pre-leaching treatment is 70℃~90℃; Preferably, the pre-leaching treatment time is 1h to 3h.

3. The recycling method as described in claim 1 or 2, characterized in that, The flow rate of the acidic slurry in the first oxygen pressure leaching treatment is 15 m³ / s. 3 / h~25m 3 / h; Preferably, the oxygen flow rate of the first oxygen pressure leaching treatment is 200 Nm³. 3 / h~300Nm 3 / h; Preferably, the temperature of the first oxygen pressure leaching treatment is 120°C to 180°C; Preferably, the pressure of the first oxygen pressure leaching treatment is 0.5 MPa to 0.8 MPa; Preferably, the oxygen partial pressure of the first oxygen pressure leaching treatment is 20%~25%; Preferably, after the first oxygen pressure leaching treatment, flash evaporation, solid-liquid separation, and cyclic leaching are performed.

4. The recycling method according to any one of claims 1-3, characterized in that, The first post-processing includes hydrothermal washing of the leaching residue, followed by sequential water washing, backflushing and pressing to obtain tailings enriched with tantalum and niobium and water washing liquid. Preferably, the solid-liquid mass ratio of the hydrothermal washing treatment is (0.8~1.1):1; Preferably, the temperature of the hydrothermal washing treatment is 80℃~90℃; Preferably, the reaction time for the hydrothermal washing treatment is 1 hour to 3 hours; Preferably, the washing liquid is reused for slurrying of tungsten tailings.

5. The recycling method according to any one of claims 1-4, characterized in that, The adjusting agent for adjusting the acidic solution to the first pH includes liquid alkali and / or lime milk; Preferably, the first pH is 2.8 to 3.

2.

6. The recycling method according to any one of claims 1-5, characterized in that, The temperature of the heating reaction is 60℃~80℃; Preferably, the heating reaction time is 0.5h to 1.5h.

7. The recycling method according to any one of claims 1-6, characterized in that, The temperature for the second oxygen pressure leaching treatment is 150℃~180℃; Preferably, the pressure of the second oxygen pressure leaching treatment is 0.6 MPa to 0.8 MPa; Preferably, the oxygen partial pressure of the second oxygen pressure leaching treatment is 15% to 25%; Preferably, the second oxygen pressure leaching treatment takes 3 to 5 hours; Preferably, the second oxygen pressure leaching treatment is followed by flash evaporation and cooling.

8. The recycling method according to any one of claims 1-7, characterized in that, The adjusting agent for adjusting the leachate to the second pH includes liquid alkali; Preferably, the second pH is 4.5 to 5.

9. The recycling method according to any one of claims 1-8, characterized in that, The temperature of the blending reaction is 80℃~90℃; Preferably, the reaction time is 3 to 5 hours.

10. The recycling method according to any one of claims 1-9, characterized in that, The second post-treatment includes mixing the blended residue with concentrated sulfuric acid for acid washing, followed by water washing, backflushing and pressing to obtain enriched tungsten slag; Preferably, the solid-liquid mass ratio of the prepared residue to concentrated sulfuric acid is (0.8~1):1; Preferably, the pH of the acid washing reaction is 1 to 1.5; Preferably, the temperature of the pickling reaction is 60℃~80℃; Preferably, the pickling reaction takes 1 to 3 hours.

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