Method for rapidly dissolving multi-phase waste refractory alloy through multi-field synergistic reinforcement

Abstract

The invention discloses a method for rapidly dissolving multi-phase waste refractory alloy through multi-field synergistic reinforcement, and belongs to the technical field of waste refractory alloy recovery. The method comprises the steps that the multiphase waste refractory alloy is placed in a composite external field of an ultrasonic field, an electric field and a temperature field, acid liquor is adopted for leaching, and a refractory metal solution is obtained; according to the method, a composite external field of an ultrasonic field, an electric field and a temperature field is adopted to synergistically promote efficient dissolution of the multiphase waste refractory alloy in acid liquor, so that the technical problem that the conventional acid leaching process is low in efficiency due to the fact that the multiphase waste refractory alloy contains multiple metal-state substances and is compact in structure, large in particle interface and slow in internal metal component mass transfer is solved.

Description

Technical Field

[0001] This invention relates to a method for dissolving multiphase waste refractory alloys, and particularly to a method for rapid dissolution of multiphase waste refractory alloys with multi-field synergistic strengthening, belonging to the field of waste refractory alloy recycling technology. Background Technology

[0002] Refractory alloys, formed by adding other elements to refractory metals (tungsten, tantalum, molybdenum, niobium, hafnium, chromium, vanadium, zirconium, and titanium), exhibit excellent high-temperature and chemical stability at high temperatures and are commonly used to manufacture high-temperature components, wear-resistant materials, and corrosion-resistant materials. Tungsten, molybdenum, rhenium, and other refractory metals, along with their binary and ternary alloys, are a class of materials with high melting points (>1800℃), excellent high-temperature strength and creep resistance, and unique thermophysical properties. Among them, tungsten-based and molybdenum-based alloys are the most commonly used refractory alloys and are widely applied in aerospace, microelectronics, nuclear energy, and other extreme environments. For example, tungsten-molybdenum alloys have excellent resistance to liquid zinc corrosion and are used to manufacture agitators, pipe and container linings, and other components in the zinc smelting industry; molybdenum-rhenium alloys are used for high-temperature components in semiconductor equipment, thermocouple wires, etc.; and tungsten-rhenium alloys are used to produce tungsten-rhenium thermocouples, electron tube cathodes, friction stir welding equipment, and high-performance structural components.

[0003] Refractory alloy scrap mainly originates from waste product recycling and offcuts and defective products generated during alloy manufacturing processes. Tungsten, molybdenum, and rhenium possess excellent properties in extreme environments such as national defense, petrochemicals, and nuclear energy. However, with the high consumption of tungsten, molybdenum, and rhenium and the decreasing grade of ore, the recycling of high-component tungsten-molybdenum-rhenium alloy scrap has attracted increasing attention.

[0004] For the recovery of refractory metals, methods such as oxidative sublimation, roasting-alkali leaching, electrochemical dissolution, and oxidative acid leaching are commonly used. Compared with traditional pyrometallurgical recovery, which is accompanied by high energy consumption, secondary oxidation, and metal loss, hydrometallurgy has the advantages of simple process and high recovery rate. Due to the high hardness, dense structure, and corrosion resistance of refractory alloys, traditional leaching processes are accompanied by problems such as difficulty in pulverization and leaching difficulties. Although efficient grinding technology is an important measure to ensure efficient leaching of metal-based solid waste, the investment cost and grinding energy consumption are both high. Direct enhanced dissolution of coarse-particle metal-based solid waste after conventional grinding is the key to efficient hydrometallurgical leaching of metal-based solid waste and reducing grinding costs. Currently, there are reports on the combined treatment of mechanical grinding and hydrometallurgy for metal-based solid waste, which can achieve good results in the leaching of fine-particle metal-based solid waste of about -200 mesh after grinding. However, waste refractory key metal resources contain a variety of metallic substances, have a dense structure, and slow mass transfer of large particle interfaces and internal metal components, resulting in conventional acid leaching processes taking several hours. Therefore, developing enhanced dissolution methods for scrap refractory alloys is of great significance. Summary of the Invention

[0005] To address the problem of the difficulty in dissolving valuable metals in waste refractory alloys in existing technologies, the present invention aims to provide a multi-field synergistic strengthening method for dissolving multiphase waste refractory alloy waste materials, which is simple in process, low in cost, and has a high metal dissolution rate, thus facilitating industrial production.

[0006] To achieve the above technical objectives, the present invention provides a method for rapid dissolution of multiphase waste refractory alloys through multi-field synergistic enhancement. The method involves placing the multiphase waste refractory alloy in a composite external field of ultrasonic field, electric field, and temperature field, and then leaching it with acid to obtain a refractory metal solution.

[0007] The ultrasonic intensity of the ultrasonic field in the composite external field is 0.2~0.5 W / cm. 2 The frequency is 30~50kHz, the voltage of the electric field is 0.1~0.5V, and the temperature of the thermal field is 60~90℃;

[0008] The acid solution contains HCl, H2SO4, HNO3, HClO and H2O2.

[0009] The key to this invention lies in employing a composite external field combining ultrasonic, electric, and thermal fields to synergistically promote the efficient dissolution of multiphase refractory waste alloys in acid. This addresses the technical problem of low efficiency in conventional acid leaching processes caused by the presence of multiple metallic substances, dense structures, large particle interfaces, and slow mass transfer of internal metal components in multiphase refractory waste alloys. The synergistic effect of the composite external field is mainly manifested in the following ways: A single ultrasonic field can generate ultrasonic cavitation effects, causing the growth, compression, and collapse of cavitation bubbles. The collapse of these cavitation bubbles creates a high-temperature, high-pressure environment accompanied by the generation of microjets, which enhances stirring, removes surface products from particles, and strengthens mass transfer, thus promoting the dissolution process of multiphase refractory waste alloys by acid. However, under the action of a single ultrasonic field, acid is insufficient to destroy the dense structure, large particle interfaces, and alloy phases in the refractory alloy. A single electric field can enhance galvanic corrosion between the multiphase components of the refractory waste alloy, but because the products of the dissolved inert metal components have low solubility and easily cover the surface of undissolved metals, the metal dissolution rate is low. Under the synergistic effect of ultrasonic and electric fields, the electric field can induce galvanic corrosion between alloy phases in multiphase waste refractory alloys, accelerating surface corrosion. Meanwhile, the ultrasonic flow and cavitation effects generated by ultrasound can rapidly peel off the product layer on the refractory alloy surface, quickly dissociate and disperse it, and enhance surface renewal of unreacted interfaces, allowing the reaction to proceed continuously. The temperature field can strengthen the corrosion of dense structures, large particle interfaces, and alloy phases by the acid solution. Therefore, the combined effect of multiple fields can improve the overall leaching efficiency of refractory alloys.

[0010] As a preferred embodiment, the total molar concentration of HCl, H2SO4, HNO3, HClO, and H2O2 in the acid solution is 2~10 mol / L, wherein the total molar percentage of HNO3, HClO, and H2O2 is 0.2~0.7. HCl, H2SO4, HNO3, and HClO in the acid solution are all acidic substances, providing protic acids to facilitate the dissolution of multiphase refractory alloys. Hydrochloric acid provides coordinating anions, which can coordinate the dissolved metal ions to form complexes, thus promoting the rapid dissolution of multiphase refractory alloys by disrupting chemical equilibrium. Nitric acid, hypochlorous acid, and H2O2 all have oxidizing properties, accelerating the dissolution of the alloy phase. Controlling the content of HNO3, HClO, and H2O2 in the acid solution within the preferred range can accelerate the dissolution of multiphase refractory alloys.

[0011] As a preferred embodiment, the solid-liquid ratio of the leaching is 1kg:20~100L.

[0012] As a preferred embodiment, the leaching time is 0.5h to 3h.

[0013] As a preferred embodiment, the leaching is completed in a U-shaped reaction tank, which has equal length, width, and height, and a hemispherical bottom with an arc angle of 45 degrees.

[0014] As a preferred embodiment, an ultrasonic rod is installed inside the U-shaped reaction tank. The length of the ultrasonic rod is in the ratio of 0.65:1 to 0.85:1 to the side length of the U-shaped tank. The ultrasonic rod is placed below the surface of the acid solution in the reaction tank, with an insertion depth of 1 / 2 to 2 / 3 of the acid solution height downwards. This invention designs the reaction tank as a U-shaped structure. This structure provides a confinement effect, and combined with the position of the ultrasonic rod and its effective nonlinear action range, a favorable ultrasonic wave reflection superposition effect exists at the bottom and around the tank to enhance the sound intensity, which is beneficial for promoting the dissolution of multiphase waste refractory alloys.

[0015] As a preferred embodiment, the total mass content of tungsten, molybdenum and rhenium in the multiphase waste refractory alloy is not less than 15%.

[0016] As a preferred embodiment, the multiphase waste refractory alloy includes at least one of waste tungsten-molybdenum alloy, waste molybdenum-rhenium alloy, and waste tungsten-rhenium alloy.

[0017] As a preferred embodiment, the multiphase waste refractory alloy is a regular particle with both length and width less than 1 cm, or an irregular particle with a long side less than 1 cm and a thickness less than 1.5 mm. Controlling the particle size of the multiphase waste refractory alloy within an appropriate range is beneficial, on the one hand, to the enhanced mass transfer effect of ultrasound on the particles, and on the other hand, to increasing the contact area between the acid and the multiphase waste refractory alloy, thereby improving reaction efficiency.

[0018] Compared with the prior art, the beneficial effects of the technical solution of this invention are as follows:

[0019] This invention employs a multi-field synergy—ultrasound, electric field, and temperature field—to promote the rapid and efficient dissolution of multiphase waste refractory alloys. The synergistic effect is primarily manifested in the following ways: the ultrasonic field promotes the rapid dissolution of powdered and fine-particle metals in acid, while simultaneously utilizing ultrasonic mechanical vibration to rapidly dissociate and disperse the dissolution products of the multiphase waste refractory alloy. However, the acoustic flow and cavitation effects generated by a single ultrasonic field are insufficient to disrupt the dense structure, large-particle interfaces, and alloy phases within the multiphase waste refractory alloy. A single electric field can enhance galvanic corrosion between the multiphase components of the waste refractory alloy, but the low solubility of the dissolved products from the inert metal components easily covers the surface of undissolved metals, resulting in a low metal dissolution rate. Under the synergistic effect of the ultrasonic and electric fields, the electric field enables galvanic corrosion between the alloy phases in the multiphase waste refractory alloy, accelerating surface corrosion. Meanwhile, the ultrasonic acoustic flow and cavitation effects rapidly peel off the product layer from the refractory alloy surface, quickly dissociating and dispersing it, enhancing surface renewal of unreacted interfaces, and ensuring continuous reaction. The temperature field can enhance the corrosion of dense structures, large particle interfaces, and alloy phases by the acid solution, thereby improving the overall leaching efficiency of refractory alloys through the synergistic effect of multiple fields. In summary, this invention significantly improves the leaching efficiency of multiphase waste refractory alloys by inducing rapid and efficient dissolution through multi-field synergy, thus solving the technical problem of low efficiency in conventional acid leaching processes caused by the presence of multiple metallic substances, dense structure, large particle interfaces, and slow mass transfer of internal metal components in multiphase waste refractory alloys.

[0020] This invention directly acid-leaches large-sized refractory metal alloys, eliminating the energy-intensive powder-making process, effectively reducing energy consumption. Furthermore, the leaching process is simple and has a high leaching recovery rate, which is beneficial for industrial applications. Detailed Implementation

[0021] The following examples are intended to further illustrate the present invention, but not to limit the scope of protection of the claims of the present invention.

[0022] Example 1

[0023] Using waste molybdenum-rhenium alloy containing 15 wt% rhenium as raw material, the particle size required to be 100% smaller than 1 cm by mass. A mixed solution of hydrochloric acid, sulfuric acid, nitric acid, hypochlorous acid, and hydrogen peroxide was used as the leaching agent, with the concentrations of hydrochloric acid (0.5 mol / L), sulfuric acid (1.5 mol / L), nitric acid (1.5 mol / L), hypochlorous acid (0.5 mol / L), and hydrogen peroxide (0.6 mol / L). The leaching was performed in an ultrasonic field (sound intensity 0.2 W / cm²). 2The leaching reaction was carried out under the synergistic effect of multiple external fields: a 40kHz frequency field, an electrochemical field (0.5V), and a temperature field (90℃). The reactor was U-shaped, with a length, width, and height of 30cm. The bottom of the reaction tank was hemispherical with an arc angle of 45 degrees. The ultrasonic rod was 19.5cm long and inserted to a depth of 2 / 3 of the leaching liquid height. The solid-liquid ratio of the waste molybdenum-rhenium alloy to the acidic leaching agent was 1g:25mL, and the leaching reaction time was 30min. After leaching, the leachate and leaching residue were obtained by filtration and washing. The leachate was a solution containing molybdenum and rhenium ions. The leaching rates of molybdenum and rhenium were as high as 99.3% and 99.9%, respectively.

[0024] Example 2

[0025] Using waste tungsten-molybdenum alloy containing 30 wt% tungsten as raw material, the particle size must meet the requirement that 100% of the particles are smaller than 0.8 cm by mass. A mixed solution of hydrochloric acid, sulfuric acid, nitric acid, hypochlorous acid, and hydrogen peroxide is used as the leaching agent, with the following concentrations: hydrochloric acid 1.0 mol / L, sulfuric acid 2.0 mol / L, nitric acid 3 mol / L, hypochlorous acid 0.5 mol / L, and hydrogen peroxide 1.0 mol / L. The leaching is performed in an ultrasonic field (sound intensity 0.5 W / cm²). 2 The leaching reaction was carried out under the synergistic effect of multiple external fields: a 40kHz frequency field, an electrochemical field (0.4V), and a temperature field (80℃). The reactor was U-shaped, with a length, width, and height of 45cm. The bottom of the reaction tank was hemispherical with an arc angle of 45 degrees. The ultrasonic rod was 35cm long and inserted to a depth of half the height of the leaching solution. The solid-liquid ratio of the waste tungsten-molybdenum alloy to the acidic leaching agent was 1g:100mL, and the leaching reaction time was 180min. After leaching, the solution and leaching residue were obtained by filtration and washing. The leaching solution contained molybdenum and rhenium ions. The alloy dissolution rate was 100%, and the dissolved tungstenic acid precipitate was formed. The remaining tungsten content in the solution was only 1.2%.

[0026] Comparative Example 1

[0027] The only difference from Example 1 is that ultrasound was not applied, and the leaching reaction was carried out under the synergistic effect of multiple external fields, namely an electrochemical field (0.5V) and a temperature field (90 °C).

[0028] The leaching rates of molybdenum and rhenium were only 77.2% and 79.3%, respectively.

[0029] Comparative Example 2

[0030] The only difference compared to Example 1 is that no electric field is applied in the ultrasonic field (sound intensity 0.5 W / cm²). 2 The leaching reaction was carried out under the synergistic effect of multiple external fields (frequency 40kHz) and temperature field (80℃).

[0031] The leaching rates of molybdenum and rhenium were 87.8% and 86.9%, respectively.

[0032] Comparative Example 3

[0033] The only difference compared to Example 1 is that a mixed solution of hydrochloric acid, sulfuric acid, nitric acid, hypochlorous acid, and hydrogen peroxide is used as the leaching agent, with the concentrations of hydrochloric acid (1.5 mol / L), sulfuric acid (3.0 mol / L), nitric acid (0.2 mol / L), hypochlorous acid (0.2 mol / L), and hydrogen peroxide (0.2 mol / L).

[0034] The leaching rates of molybdenum and rhenium were 74.6% and 75.8%, respectively.

[0035] Example 4

[0036] The only difference compared to Example 1 is that the ultrasonic rod was inserted to a depth of 1 / 4 of the leaching liquid height. The leaching rates of molybdenum and rhenium were 90.1% and 91.7%, respectively.

Claims

1. A method for rapid dissolution of a multi-phase spent refractory alloy by multi-field synergistic strengthening, characterized in that: The multi-phase waste refractory alloy is placed in a complex external field of ultrasonic field-electric field-temperature field, and acid liquid leaching is adopted to obtain a refractory metal solution. The ultrasonic intensity of the ultrasonic field in the composite external field is 0.2-0.5 W / cm 2 , the frequency is 30-50 kHz, the voltage of the electric field is 0.1-0.5 V, and the temperature of the temperature field is 60-90 DEG C. The acid liquid contains HCl, H2SO4, HNO3, HClO and H2O2.

2. The method for rapid dissolution of a multi-phase spent refractory alloy according to claim 1, wherein: The total molar concentration of HCl, H2SO4, HNO3, HClO and H2O2 in the acid liquid is 2-10 mol / L, wherein the total molar proportion of HNO3, HClO and H2O2 is 0.2-0.

7.

3. The method for rapid dissolution of a multi-phase spent refractory alloy according to claim 1 or 2, characterized in that: The solid-liquid ratio of the leaching is 1 kg:20-100 L.

4. The method for rapid dissolution of a multi-phase spent refractory alloy according to claim 1 or 2, characterized in that: The leaching time is 0.5 h-3 h.

5. The method for fast dissolution of a multi-phase spent refractory alloy according to claim 1 or 2, characterized in that: The leaching is completed in a U-shaped reaction tank, the length, width and height of the U-shaped reaction tank are equal, and the bottom is semispherical with an arc angle of 45 degrees.

6. The method of claim 5, wherein the method is characterized by: An ultrasonic rod is arranged in the U-shaped reaction tank, the length ratio of the ultrasonic rod to the length of the U-shaped tank side is 0.65:1-0.85:1, the ultrasonic rod is placed below the liquid surface of the acid liquid in the reaction tank, and the placement depth is 1 / 2 to 2 / 3 of the acid liquid height.

7. The method of claim 1, wherein the method is characterized by: The total mass content of tungsten, molybdenum and rhenium in the multi-phase waste refractory alloy is not less than 15%.

8. The method of claim 7, wherein the method is characterized by: The multi-phase waste refractory alloy comprises at least one of waste tungsten-molybdenum alloy, waste molybdenum-rhenium alloy and waste tungsten-rhenium alloy.

9. The method of claim 7, wherein the method is characterized by: The multi-phase waste refractory alloy is regular particles with a length and a width of less than 1 cm, or irregular particles with a long side of less than 1 cm and a thickness of less than 1.5 mm.