A zinc recovery device for waste hard alloy and grinding material

Abstract

The application provides a zinc smelting recovery device for waste hard alloy and grinding material, which comprises a main crucible for containing zinc ingots and alloy materials to be treated, the alloy materials to be treated comprising waste hard alloy or grinding material; a heating device for heating the zinc ingots and the alloy materials to be treated to form a zinc metal melt and to heat the zinc liquid to volatilize; a mechanical stirring device with a stirring end extending into the zinc metal melt from above the main crucible, the mechanical stirring device being used for stirring the zinc metal melt to make light impurities in the alloy materials to be treated float on the surface of the zinc metal melt; and a secondary crucible arranged on the side of the main crucible, the inlet of the secondary crucible being communicated with the liquid surface of the zinc metal melt, and the light impurities on the surface of the zinc metal melt being introduced and collected into the secondary crucible under the stirring action of the mechanical stirring device. The application can realize the removal of impurities and purification of coated hard alloy block materials and hard alloy grinding powder materials with high impurity content.

Description

Technical Field

[0001] This application relates to the field of cemented carbide, and more specifically, to a zinc melting and recycling device for waste cemented carbide and grinding materials. Background Technology

[0002] Cemented carbide materials possess high hardness, high engineering strength, good wear resistance, and corrosion resistance. They are often made into superhard tools and are widely used in machining cutting tools, drilling tools and hammers in mining and engineering, and mold making. Cemented carbide is a composite material mainly composed of the hard phase tungsten carbide and the binder phases cobalt and nickel. The mineral resources contained in the Earth's crust are extremely limited, and mining and producing them is very expensive. Therefore, when cemented carbide materials fail, the waste cemented carbide is often recycled and reused through certain methods.

[0003] Common methods for recycling cemented carbide materials include hydrometallurgy, electrolysis, mechanical crushing, and zinc smelting. Among these, zinc smelting is the most environmentally friendly method for reusing cemented carbide. During the wetting process of cemented carbide with molten zinc, zinc forms an alloy with cobalt or nickel, disrupting the original dense structure of the cemented carbide and causing the tungsten carbide framework to swell and decay from the surface inwards. Subsequently, utilizing the difference in saturated vapor pressure between the different metals, the molten zinc is evaporated, and the zinc liquid is completely separated from the cobalt and nickel, then condensed and recovered in a special container. This process transforms the dense cemented carbide into a brittle one. After mechanical ball milling, the molten zinc can be processed into pre-alloyed cemented carbide powder for later use.

[0004] Traditional zinc smelting methods suffer from the problem of difficult impurity separation. When cemented carbide is used to manufacture cutting tools, some tools are coated with single or composite coatings of TiC, TiCN, TiAlN, TiN, and Al2O3. These coatings easily form lamellar inclusions during zinc smelting recycling, significantly reducing the bending strength of the cemented carbide products. Therefore, the zinc smelting powder needs to undergo prolonged ball milling to disperse the impurities. Furthermore, the grinding and polishing process using diamond and silicon carbide wheels during tool manufacturing also generates a large amount of cemented carbide grinding debris. This debris contains SiC, diamond particles, and oil impurities. Compared to coated waste cemented carbide tools, the debris has a higher impurity content and is more scattered, making it difficult to recover using traditional zinc smelting methods. Generally, this debris is recovered through hydrometallurgy to form tungsten and cobalt salts. However, hydrometallurgy involves large amounts of acids and alkalis, wastewater, and waste salts, resulting in high processing costs and long processing times. Utility Model Content

[0005] In view of one of the defects in the prior art, the purpose of this application is to provide a zinc melting and recycling device for waste cemented carbide and grinding materials.

[0006] A first aspect of this application provides a zinc melting and recycling device for waste cemented carbide and abrasive materials, comprising: The main crucible is used to hold zinc ingots and alloy materials to be processed, including scrap cemented carbide or grinding media. A heating device is located below the main crucible. The heating device is used to heat the zinc ingot and the alloy material to be processed to form a zinc molten metal, and to heat the zinc molten metal to volatilize. A mechanical stirring device is located above the main crucible, with its stirring end extending into the zinc molten metal from above the main crucible. The mechanical stirring device is used to stir the zinc molten metal, causing light impurities in the alloy material to be treated to float on the surface of the zinc molten metal. A secondary crucible is located on the side of the main crucible. The inlet of the secondary crucible is connected to the liquid surface of the zinc molten metal. Under the stirring action of the mechanical stirring device, light impurities on the surface of the zinc molten metal are diverted and collected into the secondary crucible.

[0007] Optionally, the main crucible is made of graphite.

[0008] Optionally, the stirring end of the mechanical stirring device is made of titanium alloy.

[0009] Optionally, the secondary crucible is made of graphite.

[0010] Optionally, a pair of auxiliary crucibles are provided on the side of the main crucible, and the pair of auxiliary crucibles are arranged symmetrically.

[0011] Optionally, the height of the auxiliary crucible is lower than the liquid level in the main crucible.

[0012] Optionally, the auxiliary crucible is connected to the main crucible via a flow channel.

[0013] The zinc melting recovery device for waste cemented carbide and grinding materials provided in this application, by setting a mechanical stirring device in the main crucible and setting a secondary crucible on the side of the main crucible, can concentrate the lighter impurities in the alloy material to be treated to the surface of the zinc molten metal. The lighter impurities in the alloy material to be treated floating on the surface of the molten metal are collected by guiding and removing slag. After the zinc liquid evaporates, the WC-Co cemented carbide is separated from the zinc, thereby realizing the removal and purification of coated cemented carbide blocks and cemented carbide grinding powder with high impurity content.

[0014] Other technical effects resulting from the additional features will be further illustrated in the corresponding embodiments. Attached Figure Description

[0015] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of a zinc melting and recycling apparatus for waste cemented carbide and abrasive materials according to an exemplary embodiment; Figure 2 This is a flowchart illustrating a zinc melting and recycling method for waste cemented carbide and abrasive materials according to an exemplary embodiment; In the diagram: 1 is the main crucible, 2 is the alloy material to be processed, 3 is the mechanical stirring device, 4 is the auxiliary crucible, and 5 is the water-cooling jacket. Detailed Implementation

[0016] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all fall within the protection scope of the present application. Parts not described in detail in the following embodiments can be implemented using existing technology.

[0017] Existing zinc melting methods are insufficient for effectively separating impurities from waste cemented carbide and grinding materials, while other methods suffer from high processing costs or long processing times. To address these issues, this application provides a zinc melting recovery device for waste cemented carbide and grinding materials, thus resolving the aforementioned problems.

[0018] Reference Figure 1 As shown in one embodiment of this application, a zinc melting and recycling device for waste cemented carbide and abrasive materials includes a main crucible 1, a heating device, a mechanical stirring device 3, and an auxiliary crucible 4. The main crucible 1 holds zinc ingots and alloy materials to be processed, the alloy materials to be processed 2 including waste cemented carbide or abrasive materials. The heating device is located below the main crucible 1 and is used to heat the zinc ingots and alloy materials to be processed, forming a zinc molten metal, and to cause the zinc liquid to evaporate. It can be a conventional zinc melting furnace. The mechanical stirring device 3 is located above the main crucible 1, with its stirring end extending into the zinc molten metal from above the main crucible 1. The mechanical stirring device 3 is used to stir the zinc molten metal, causing impurities in the alloy materials to be processed 2 to float on the surface of the zinc molten metal. The auxiliary crucible 4 is located on the side of the main crucible 1, and its inlet is connected to the surface of the zinc molten metal. Under the stirring action of the mechanical stirring device 3, light impurities on the surface of the zinc molten metal are diverted and collected into the auxiliary crucible 4.

[0019] Specifically, the commonly used cemented carbide coating component is mainly TiC (density 4.93 g / cm³). 3 TiCN (density 5.08 g / cm³) 3 Al2O3 (density 3.97 g / cm³) 3 After cemented carbide is ground by grinding wheels and diamond, the main impurities in the grinding media include SiC (density 3.21 g / cm³). 3 Diamond (density 3.51 g / cm³) 3The above components are related to zinc (density 7.14 g / cm³). 3 WC (density 15.63 g / cm³) 3 ) and Co (density 8.9 g / cm³) 3 The alloy has a large density difference.

[0020] When zinc-coated cemented carbide blocks are melted, Zn melts at temperatures above 420℃ to form a liquid phase, gradually forming an alloy melt with Co, causing the cemented carbide to swell. The TiC, TiCN, and other composite coatings on the surface will peel off in a lamellar structure. Due to the density difference between the Zn-Co melt and the coating, the coating easily floats directly on the melt surface, thus achieving mechanical separation. When zinc melt is used to treat grinding powder, impurities such as SiC, Al2O3, and diamond particles are mixed in the grinding powder. The variable-speed stirring of the mechanical stirring device 3 gradually concentrates these impurities to the surface of the Zn-Co melt. Subsequently, slag is removed by diversion, achieving low-cost and rapid impurity separation.

[0021] When heated, cobalt and Zn form a melt, while WC does not melt. The zinc metal melt mentioned above is a Zn-Co melt formed by melting zinc with the alloy to be treated. Light impurities refer to lighter impurities such as TiC, TiCN, Al2O3, SiC, and diamond particles in the cemented carbide. These light impurities can float on the surface of the zinc metal melt.

[0022] It should be noted that, in order to ensure that light impurities are completely diverted and collected to the secondary crucible 4, the diversion and collection process may also include some zinc molten metal and a small amount of WC-Co. The diversion of some zinc molten metal to the secondary crucible 4 is only a small amount on the surface, and the zinc will subsequently volatilize. Furthermore, the small amount of cemented carbide that enters the secondary crucible 4 with the impurities will undergo further treatment, essentially resulting in impurity enrichment. Therefore, this does not affect the impurity removal and purification effect of the alloy in the main crucible.

[0023] In the above embodiments of this application, by setting a mechanical stirring device 3 in the main crucible 1 and setting a secondary crucible 4 on the side of the main crucible 1, the lighter impurities in the alloy material 2 to be treated can be concentrated to the surface of the zinc metal melt. The lighter impurities in the alloy material 2 to be treated floating on the surface of the melt are collected by slag removal. The secondary crucible 4 mainly contains impurities and a small amount of cemented carbide. After the zinc melt evaporates, the WC-Co cemented carbide is separated from the zinc, thereby realizing the removal and purification of coated cemented carbide blocks and cemented carbide grinding powder with high impurity content.

[0024] In some specific embodiments of this application, the main crucible 1 is made of graphite.

[0025] In the above embodiments of this application, a graphite-based main crucible 1 is used, which is durable at high temperatures, does not react with metals, and is also low in cost.

[0026] In some specific embodiments of this application, the stirring end of the mechanical stirring device 3 is made of titanium alloy.

[0027] Specifically, the stirring end of the mechanical stirring device 3 (including the stirring paddle and part of the stirring rod) extends into the main crucible 1, and the stirring rod extends outside the main crucible 1 and is connected to an external motor, through which the stirring speed is adjusted. The stirring rod is cooled at its external end by a water-cooled sleeve 5.

[0028] In the above embodiments of this application, the stirring end is made of titanium alloy that does not react with zinc, and is durable at high temperatures, meeting the stirring strength requirements.

[0029] In some specific embodiments of this application, the secondary crucible 4 is made of graphite.

[0030] In some specific embodiments of this application, a pair of auxiliary crucibles 4 are provided on the side of the main crucible 1, communicating with it through a flow channel. The pair of auxiliary crucibles 4 are symmetrically arranged, attached to both sides of the main crucible 1 like ears, and the height of the auxiliary crucibles 4 is lower than the liquid level in the main crucible 1. Through the flow channel between the main crucible 1 and the auxiliary crucibles 4, which allows unidirectional flow of the melt, a portion of the surface melt can flow into the auxiliary crucibles 4 when the solution boils or is stirred. The specific structure of the flow channel can be implemented using existing technology.

[0031] Figure 2 A method for zinc smelting and recycling of waste cemented carbide and abrasive materials using the above-described apparatus is shown, the method comprising the following steps: S1. Place the alloy material to be treated and the zinc ingot in the main crucible, introduce protective gas into the zinc furnace, and heat the zinc ingot and the alloy material to be treated to form a zinc metal melt; S2. Stir the zinc molten metal to make the light impurities in the alloy material to be treated float on the surface of the zinc molten metal; S3. Stirring causes light impurities on the surface of the melt to be drawn and collected into the secondary crucible; S4. Increase the temperature and adjust the vacuum level to allow the zinc liquid to evaporate, separating the alloy material from the zinc.

[0032] In order to form a zinc molten metal, in some specific embodiments of this application, zinc ingots and alloy materials to be treated are heated to form a zinc molten metal, wherein the temperature is 420°C-550°C.

[0033] Specifically, the protective gas used during heating is Ar or N2. At temperatures of 420℃-550℃, the viscosity of the zinc molten metal is 2.65 mPa·s to 1.87 mPa·s, and the surface tension is 0.8 N / m to 0.67 N / m. The state of the zinc-cobalt alloy melt is determined based on the viscosity and surface tension of the zinc molten metal to facilitate control of the alloy melt viscosity and impurity removal.

[0034] In order to make light impurities float on the surface of the zinc molten metal, in some specific embodiments of this application, the zinc molten metal is stirred so that the light impurities in the alloy material to be treated float on the surface of the zinc molten metal, including: the stirring rate of mechanical stirring is 15-30 r / min.

[0035] It should be noted that in this step, combined with the effect of gravity, the components other than light impurities sink and are effectively separated from the light impurities mentioned above.

[0036] In order to concentrate light impurities on the surface of Zn-Co melt, in some specific embodiments of this application, the light impurities on the surface of the melt are drawn and collected into the secondary crucible by stirring, including: at a temperature of 400-800°C, the light impurities on the surface of the melt are drawn into the secondary crucible by mechanical speed-changing stirring.

[0037] In the embodiments described above, in the molten state, lighter impurities float on the surface of the melt. Stirring guides these surface scum impurities to the auxiliary crucible. The control of the stirring rate and temperature is similar to that in boiling water filled with floating matter, gentle stirring helps the floating matter flow away along the outer wall of the vessel.

[0038] To achieve the evaporation of molten zinc in the main crucible, in some specific embodiments of this application, the temperature is increased and the vacuum level is adjusted, with the vacuum range being -0.05 MPa to -0.01 MPa. As the temperature increases, the vacuum level decreases, allowing the molten zinc to evaporate. Specifically, the temperature is increased to 990°C. 990°C is the temperature at which zinc evaporates; if the temperature is too high, the zinc will boil violently and be difficult to control.

[0039] After the above separation, the main crucible contains swollen and broken WC-Co cemented carbide. Swelling refers to the reaction between Co and zinc in WC-Co to form a viscous liquid phase, followed by the volatilization of Zn. This process disrupts the original dense WC-Co structure (with Co acting as a binder), forming broken or relatively loose cemented carbide blocks, which facilitates subsequent ball milling. The secondary crucible contains impurities such as Al2O3, SiC, C, and Cu, as well as a small amount of WC-Co cemented carbide fragments, thus achieving the effect of impurity separation.

[0040] The embodiments described above in this application can quickly and effectively separate impurities such as TiCN coating, SiC, and diamond, as well as hard alloys, in a zinc furnace without the need for solvents such as acids and alkalis. This method has the advantages of low separation cost, high separation efficiency, and being environmentally friendly.

[0041] The preferred features in the above embodiments can be used individually in any embodiment, or in any combination thereof, provided they do not conflict with each other. Furthermore, parts not described in detail in the embodiments can be implemented using existing technologies.

[0042] The following examples and comparative examples will be used to further illustrate this application in order to better understand the above-mentioned technical solutions. It should be understood that the following are only some examples and are not intended to limit this application.

[0043] Application Example 1: Under argon protection, zinc ingots and impurity-laden grinding material were heated to a furnace temperature of 450°C at a rate of 5°C / min. Subsequently, the heating rate was reduced to 680°C and held for 5 hours at a rate of 2°C / min, with the vacuum maintained at -0.05 MPa. Stirring was performed during this holding period at a rate of 50 r / min to disperse impurities and cemented carbide. After 3 hours, the stirring speed was reduced to 30 r / min, and then further reduced to 10 r / min for the next hour, promoting the separation of impurities and cemented carbide from the molten zinc, with low-density impurities suspended on the surface. Finally, the temperature was raised to 750°C, and the stirring blades were raised to the surface of the melt. Stirring was performed at a rate of 50 r / min for 3-5 minutes to guide impurities to the auxiliary crucible. The temperature was then raised to 990°C, with the vacuum maintained at -0.01 MPa, and vacuuming was initiated to promote Zn evaporation and recovery. Results showed that impurities and a small amount of cemented carbide were present in the auxiliary crucible, while the cemented carbide impurity content in the main crucible met the requirements for cemented carbide recovery.

[0044] Comparative Example 1: Under argon protection, zinc ingots and impurity-laden grinding material were heated to a furnace temperature of 450°C at a rate of 5°C / min. The heating rate was then reduced to 680°C at 2°C / min and held for 5 hours under vacuum of -0.05 MPa. Stirring was performed at a rate of 50 r / min during the holding process. Finally, the temperature was raised to 750°C, and the stirring blades were raised to the melt surface. Stirring was performed at 50 r / min for 3-5 minutes to guide impurities to a secondary crucible. The temperature was then raised to 990°C, and vacuum was maintained at -0.01 MPa to induce Zn evaporation and recovery. The results showed that continuous high-speed stirring failed to enrich impurities on the melt surface. Compared to Example 1, light impurities in the crucible could not be suspended, and there was no significant separation between impurities and the alloy.

[0045] Comparative Example 2: Under argon protection, zinc ingots and impurity-laden grinding material were heated to a furnace temperature of 450°C at a rate of 5°C / min. Subsequently, the heating rate was reduced to 680°C at 2°C / min and held for 5 hours under vacuum of -0.05 MPa. Stirring was performed during this holding period at a rate of 50 r / min to disperse impurities and cemented carbide. After 3 hours, the stirring speed was reduced to 30 r / min, and then further reduced to 10 r / min for the next hour to promote separation of impurities and cemented carbide from the molten zinc, with low-density impurities suspended on the surface. Finally, the temperature was raised to 750°C, with vacuum maintained at -0.01 MPa. The stirring blades were raised to the surface of the melt, and stirring was performed at 50 r / min for 3-5 minutes. Impurities were then diverted to the auxiliary crucible, and vacuuming was initiated to promote Zn evaporation and recovery. The results showed that the temperature did not reach the optimal level for zinc evaporation, and incomplete zinc evaporation was observed in both the main and auxiliary crucibles.

[0046] In the description of the embodiments of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0048] In the description of the embodiments in this application, "multiple" means two or more, unless otherwise explicitly specified. In this application, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0049] The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or devices.

[0050] The foregoing has described some specific embodiments of this application. It should be understood that this application is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the substantive content of this application. The above-described preferred features can be used in any combination without conflict.

Claims

1. A zinc melting and recycling device for waste cemented carbide and grinding materials, characterized in that, include: The main crucible is used to hold zinc ingots and alloy materials to be processed, including scrap cemented carbide or grinding materials. A heating device is located below the main crucible. The heating device is used to heat the zinc ingot and the alloy material to be processed to form a zinc molten metal, and to heat the zinc molten metal to volatilize. A mechanical stirring device is located above the main crucible, with its stirring end extending into the zinc molten metal from above the main crucible. The mechanical stirring device is used to stir the zinc molten metal, causing light impurities in the alloy material to be treated to float on the surface of the zinc molten metal. A secondary crucible is located on the side of the main crucible. The inlet of the secondary crucible is connected to the liquid surface of the zinc molten metal. Under the stirring action of the mechanical stirring device, light impurities on the surface of the zinc molten metal are diverted and collected into the secondary crucible.

2. The zinc melting and recycling device for waste cemented carbide and grinding materials according to claim 1, characterized in that, The main crucible is a graphite crucible.

3. The zinc melting and recycling device for waste cemented carbide and grinding materials according to claim 1, characterized in that, The stirring end of the mechanical stirring device is made of titanium alloy.

4. The zinc melting and recycling device for waste cemented carbide and grinding materials according to claim 1, characterized in that, The auxiliary crucible is a graphite crucible.

5. The zinc melting and recycling device for waste cemented carbide and grinding materials according to claim 1, characterized in that, The main crucible has a pair of auxiliary crucibles on its side, and the pair of auxiliary crucibles are arranged symmetrically.

6. The zinc melting and recycling device for waste cemented carbide and grinding materials according to claim 1, characterized in that, The height of the auxiliary crucible is lower than the liquid level in the main crucible.

7. The zinc melting and recycling device for waste cemented carbide and grinding materials according to claim 1, characterized in that, The auxiliary crucible is connected to the main crucible through a flow channel.

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