阅读说明：本技术 一种从硬质合金废料中回收钨的方法 (Method for recovering tungsten from hard alloy waste ) 是由 李亮星 朱志城 董学舒 杨靖伟 贾梦熹 梁勇 刘晶静 于 2021-07-01 设计创作，主要内容包括：一种从硬质合金废料中回收钨的方法,首先将NaCl与KCl按照摩尔比0.7～1.3：1配制成支持电解质,再在支持电解质中加入质量百分数为4.0％～8.0％的Na-2WO-4均匀混合后作为熔盐电解质；而后将配置的混合熔盐电解质置于电解槽中,升温融化混合熔盐电解质,以硬质合金废料作阳极,镍片作阴极,接通直流电源电解,硬质合金废料阳极发生电化学溶解,在阴极上得到金属钨,本发明具有工艺流程简单、成本低、能耗少、污染小等优点。(A method for recovering tungsten from hard alloy waste materials comprises the following steps of firstly, mixing NaCl and KCl according to a molar ratio of 0.7-1.3: 1 preparing a supporting electrolyte, and adding Na with the mass percent of 4.0-8.0% into the supporting electrolyte 2 WO 4 Uniformly mixing the mixture to be used as molten salt electrolyte; and then placing the prepared mixed molten salt electrolyte in an electrolytic cell, heating to melt the mixed molten salt electrolyte, taking the hard alloy waste as an anode and a nickel sheet as a cathode, connecting a direct current power supply for electrolysis, and electrochemically dissolving the hard alloy waste anode to obtain metal tungsten on the cathode.)

1. A method for recovering tungsten from hard alloy scraps is characterized by comprising the following specific steps:

(1) NaCl-KCl is used as supporting electrolyte, and Na with a certain mass is added₂WO₄Mixing the electrolyte with a supporting electrolyte uniformly to prepare a mixed molten salt electrolyte;

(2) and (2) placing the mixed molten salt electrolyte prepared in the step (1) in an electrolytic bath, heating to melt the mixed molten salt electrolyte, taking the pretreated hard alloy waste as an anode and the pretreated nickel sheet as a cathode, switching on a direct current power supply for electrolysis, electrochemically dissolving the hard alloy waste anode, and obtaining metal tungsten on the cathode.

2. The method for recovering tungsten from cemented carbide scrap according to claim 1 wherein in step (1), the molar ratio of NaCl to KCl in the supporting electrolyte is 0.7-1.3: 1.

3. The method for recovering tungsten from cemented carbide scrap according to claim 1 wherein in step (1), the Na is₂WO₄The adding amount accounts for 4.0-8.0 percent of the mass percentage of the mixed molten salt electrolyte.

4. The method according to claim 1, wherein in the step (2), the electrolysis temperature in the electrolytic cell is 700-730 ℃, and the electrolysis is performed at a temperature 40-50 ℃ higher than the primary crystallization temperature of the electrolyte.

5. The method for recovering tungsten from cemented carbide scrap according to claim 1, wherein the pretreatment of the cemented carbide scrap before electrolysis in step (2) comprises: scrubbing the hard alloy waste by using acetone to remove organic matters attached to the surface of the hard alloy waste, then soaking the hard alloy waste by using dilute hydrochloric acid to remove oxides on the surface of the hard alloy waste, finally cleaning the hard alloy waste by using distilled water, and drying the hard alloy waste for later use.

6. The method for recovering tungsten from the hard alloy scrap according to claim 1, wherein in the step (2), the cathode nickel sheet is pretreated before electrolysis by the following steps: firstly, putting a nickel sheet into HCl solution with the ratio of 1: 1 for soaking for 10min, and then polishing by metallographic abrasive paper and Al₂O₃Polishing, ultrasonically cleaning the nickel sheet by using distilled water and absolute ethyl alcohol, and drying for later use.

7. The method for recovering tungsten from cemented carbide scrap according to claim 1, wherein in step (2), the electrolysis is performed in a constant voltage mode, the voltage is controlled to be 1.1-1.3V, and the electrolysis time is 8-10 h.

Technical Field

The invention relates to the technical field of alloy recovery treatment, in particular to a method for recovering tungsten from hard alloy waste.

Background

Cemented carbide has high hardness and good wear resistance and plays an extremely important role in modern tool materials. With the continuous expansion of the application field of the hard alloy, the output of the hard alloy in China is also improved year by year, and the hard alloy waste materials generated in the production and use processes are also gradually increased. Tungsten is a main metal for preparing hard alloy, the content of tungsten in the hard alloy waste reaches 40% -95%, and tungsten resources face to be in short supply with continuous exploitation of tungsten ore in China, so that the hard alloy waste becomes an important tungsten secondary resource. How to recover valuable metal tungsten from hard alloy waste materials so as to establish an effective resource recovery and reutilization system, which not only effectively reutilizes the hard alloy waste materials, but also can solve the problems of environmental pollution, resource shortage and the like, and has important significance for relieving the demand pressure of tungsten resources in China.

At present, the methods for recycling the hard alloy waste materials comprise a zinc melting method, an electro-melting method, a saltpeter method, a mechanical crushing method and the like, but the methods generally have the defects of complex treatment process, high energy consumption, serious environmental pollution, high investment cost and the like:

the zinc melting method has high energy consumption, the electric quantity consumed by treating 1 ton of hard alloy waste is about 6000-12000 ℃, and harmful impurities in regenerated hard alloy products are easy to accumulate;

the electro-dissolution method is only suitable for treating the hard alloy with the cobalt content of more than 10 percent, and corrosive chemical reagents are needed in the recovery process, which is not beneficial to environmental protection;

the niter method has simple process and low energy consumption, but a large amount of nitrogen oxides generated in the production process pollute the environment;

when the mechanical crushing method is used for crushing the hard alloy waste, metal material scraps of a tool are easily brought into the crushed material, so that pollution is generated, and particularly impurities such as iron are introduced.

Disclosure of Invention

The present invention provides a method for recovering tungsten from cemented carbide scrap to solve the above-mentioned problems of the background art.

The technical problem solved by the invention is realized by adopting the following technical scheme:

a method for recovering tungsten from hard alloy scraps comprises the following specific steps:

(1) to be provided withNaCl-KCl as supporting electrolyte, adding Na₂WO₄Mixing the electrolyte with a supporting electrolyte uniformly to prepare a mixed molten salt electrolyte;

(2) and (2) placing the mixed molten salt electrolyte prepared in the step (1) in an electrolytic bath, heating to melt the mixed molten salt electrolyte, taking the pretreated hard alloy waste as an anode and the pretreated nickel sheet as a cathode, switching on a direct current power supply for electrolysis, electrochemically dissolving the hard alloy waste anode, and obtaining metal tungsten on the cathode.

In the invention, in the step (1), the molar ratio of NaCl to KCl in the supporting electrolyte is 0.7-1.3: 1.

In the present invention, in the step (1), the Na is₂WO₄The adding amount accounts for 4.0-8.0 percent of the mass percentage of the mixed molten salt electrolyte.

In the invention, in the step (2), the electrolysis temperature in the electrolytic cell is 700-730 ℃ due to different electrolyte compositions, and the specific temperature is 40-50 ℃ higher than the primary crystal temperature of the electrolyte for electrolysis according to the primary crystal temperature of the electrolyte.

In the invention, in the step (2), the length x width of the hard alloy scrap anode is 1.5cm x 1.5cm, the hard alloy scrap is pretreated before electrolysis, the hard alloy scrap is scrubbed by acetone to remove organic matters such as grease and the like attached to the surface of the hard alloy scrap, then oxide on the surface of the hard alloy scrap is removed by soaking in dilute hydrochloric acid, and finally the hard alloy scrap is cleaned by distilled water to remove hydrochloric acid, chloride ions and the like on the surface of the hard alloy scrap and dried for later use.

In the invention, in the step (2), the length multiplied by width specification of the cathode nickel sheet is 2.0cm multiplied by 1.5cm, the cathode nickel sheet is pretreated before electrolysis, firstly, the nickel sheet is put into HCl solution with the ratio of 1: 1 to be soaked for 10min, and then, metallographic abrasive paper is used for polishing and Al is used for polishing₂O₃Polishing, ultrasonically cleaning the nickel sheet by using distilled water and absolute ethyl alcohol, and drying for later use.

In the invention, in the step (2), a constant voltage mode is adopted for electrolysis, the voltage range is controlled to be 1.1-1.3V, and the electrolysis time is 8-10 h.

Has the advantages that: compared with the traditional method, the method directly takes the hard alloy waste as the anode, adopts the molten salt electrolysis method to recover the valuable metals in the hard alloy waste, realizes the dissolution of the anode by controlling the electrolysis voltage, separates out the metal tungsten on the cathode, and can realize the electrochemical dissolution of different metals in the hard alloy waste by adjusting the electrolysis voltage so as to realize the effective separation of the metals in the hard alloy waste, and has the advantages of no emission of pollution gas, environmental protection and low recovery cost.

Drawings

FIG. 1 is a SEM illustration of the cathode product metal tungsten in an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the comparison between before and after the electrolysis of the cemented carbide scrap according to the example of the present invention.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further explained below by combining the specific drawings.

Example 1

A method for recovering tungsten from hard alloy scraps comprises the following specific steps:

firstly, NaCl and KCl are uniformly mixed according to the molar ratio of 1: 1 to obtain NaCl-KCl supporting electrolyte, and then Na with the mass fraction of 6.0 percent is added into the NaCl-KCl supporting electrolyte₂WO₄And uniformly mixing to obtain mixed molten salt electrolyte, finally placing the mixed molten salt electrolyte in an electrolytic cell, taking the hard alloy waste as an anode and a nickel sheet as a cathode, controlling the electrolytic voltage to be 1.2V, the electrolytic temperature to be 700 ℃, and the electrolytic time to be 8h, wherein the hard alloy waste anode is subjected to obvious electrochemical dissolution, and metal tungsten with the purity of 99.5% is obtained at the cathode.

Example 2

A method for recovering tungsten from hard alloy scraps comprises the following specific steps:

first, NaCl and KCl are mixed evenly according to the molar ratio of 0.7: 1 to obtain NaCl-KCl supporting electrolyte, and Na with the mass fraction of 4.0 percent is added into the NaCl-KCl supporting electrolyte₂WO₄Mixing uniformly to obtain mixed molten salt electrolyte, and finally mixingThe mixed molten salt electrolyte is placed in an electrolytic cell, the hard alloy waste is used as an anode, a nickel sheet is used as a cathode, the electrolytic voltage is controlled to be 1.1V, the electrolytic temperature is 710 ℃, the electrolytic time is 9 hours, the hard alloy waste anode is subjected to obvious electrochemical dissolution, and the metal tungsten with the purity of 99.1% is obtained at the cathode.

Example 3

A method for recovering tungsten from hard alloy scraps comprises the following specific steps:

first, NaCl and KCl are mixed evenly according to the mol ratio of 1.3: 1 to obtain NaCl-KCl supporting electrolyte, and Na with the mass fraction of 8.0 percent is added into the NaCl-KCl supporting electrolyte₂WO₄And uniformly mixing to obtain mixed molten salt electrolyte, finally placing the mixed molten salt electrolyte in an electrolytic cell, taking the hard alloy waste as an anode and a nickel sheet as a cathode, controlling the electrolytic voltage to be 1.3V, the electrolytic temperature to be 730 ℃, and the electrolytic time to be 10h, wherein the hard alloy waste anode is subjected to obvious electrochemical dissolution, and metal tungsten with the purity of 99.3% is obtained at the cathode.

In examples 1 to 3, the cemented carbide scrap was subjected to pretreatment before and after electrolysis, as shown in fig. 2, and both the cemented carbide scrap and the nickel piece were subjected to pretreatment:

pretreating the hard alloy waste, scrubbing the hard alloy waste by using acetone to remove organic matters such as grease and the like attached to the surface of the hard alloy waste, then soaking the hard alloy waste by using dilute hydrochloric acid to remove oxides on the surface of the hard alloy waste, finally cleaning the hard alloy waste by using distilled water to remove hydrochloric acid, chloride ions and the like on the surface of the hard alloy waste, and drying the hard alloy waste for later use;

pretreating the cathode nickel sheet, firstly soaking the nickel sheet in HCl solution at a ratio of 1: 1 for 10min, then polishing with metallographic abrasive paper and Al₂O₃Polishing, ultrasonically cleaning the nickel sheet by using distilled water and absolute ethyl alcohol, and drying for later use.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.