阅读说明：本技术 一种强化净化硫酸锌溶液的方法 (Method for intensively purifying zinc sulfate solution ) 是由 张利波 李静 罗永光 曲洪涛 谢庭芳 杨大锦 王仕兴 顾利坤 张宏 夏洪应 李云 于 2018-08-07 设计创作，主要内容包括：本发明公开了一种强化净化硫酸锌溶液的方法,步骤包括：锌粉通过加压设备,以非氧化性气体为保护介质和加压介质,以喷射流的方式射入硫酸锌溶液中对其进行净化处理,处理过程中伴随超声波,经反应—固液分离后,获得净化后的合格硫酸锌溶液。根据本发明提供的净化方法,有效地优化了锌粉—溶液之间的固-液传热过程,保证反应界面温度高于溶液温度,促进化学反应热力学过程,能够在高效除杂的同时有效的降低锌粉耗量和缩短置换反应时间,减少渣量的产生及提高后续渣中有价金属的回收；同时避免硫酸锌整体溶液温度的增加,降低生产过程能耗；综合实现了经济效益和环境效益。(The invention discloses a method for intensively purifying a zinc sulfate solution, which comprises the following steps: the zinc powder is injected into the zinc sulfate solution in a jet flow mode by a pressurizing device by taking non-oxidizing gas as a protective medium and a pressurizing medium, and the zinc powder is purified, wherein the qualified zinc sulfate solution after purification is obtained after reaction-solid-liquid separation along with ultrasonic waves in the treatment process. According to the purification method provided by the invention, the solid-liquid heat transfer process between zinc powder and a solution is effectively optimized, the temperature of a reaction interface is ensured to be higher than the temperature of the solution, the thermodynamic process of chemical reaction is promoted, the consumption of the zinc powder can be effectively reduced while the impurities are efficiently removed, the replacement reaction time is shortened, the generation of slag amount is reduced, and the recovery of valuable metals in subsequent slag is improved; meanwhile, the increase of the temperature of the whole zinc sulfate solution is avoided, and the energy consumption in the production process is reduced; the economic benefit and the environmental benefit are comprehensively realized.)

1. The method for strengthening and purifying the zinc sulfate solution comprises the step of strengthening and purifying the zinc sulfate solution by applying ultrasonic waves to a reaction system in the zinc powder purifying process.

2. A method according to claim 1, characterized in that the zinc powder has a particle size of 0.08 to 0.4mm, preferably 0.12 to 0.18 mm.

3. The method of claim 1, wherein the ultrasonic frequency is 20 kHz.

4. The method according to claim 2, characterized in that the ultrasonic power is 100W to 3000W, preferably 500W to 2500W.

5. The method of claim 1, further comprising the step of purging the zinc sulphate solution by passing zinc powder into the zinc sulphate solution as a spray.

6. The method as defined in claim 5, characterized in that the zinc powder is passed through a spraying device, using a non-oxidizing gas as a protective fluid and a pressurizing medium, to form a spray jet at a set pressure, to be passed into the zinc sulphate solution;

the set pressure is 0.1 to 4.4MPa, preferably 0.3 to 3.5 MPa.

7. A method as defined in claim 5, characterized in that a zinc powder-containing jet is passed into the zinc sulphate solution from the bottom or the middle of the reaction vessel.

8. A method according to any one of claims 1 to 7, characterized in that zinc dust is added in an amount of 1.2 to 2.5 times, preferably 1.5 to 2 times the total mass of the metal impurities to be removed in the zinc sulphate solution.

9. The method according to claim 5, characterized in that the reaction temperature is 50-80 ℃, preferably 50-70 ℃ when the zinc sulfate solution is purified;

when the zinc sulfate solution is the leachate produced by the zinc hydrometallurgy, the temperature of the zinc sulfate solution does not need to be raised in the purification reaction process.

10. The method according to claim 5, characterized in that the time of the purification treatment is 10-60 minutes, preferably 20-50 minutes when the zinc sulfate solution is purified.

Technical Field

The invention relates to the field of fine chemical engineering, in particular to a method for intensively purifying a zinc sulfate solution.

Background

The zinc sulfate solution in the zinc hydrometallurgy often contains impurities such as copper, cadmium, cobalt, nickel, arsenic, antimony, germanium and the like, which are extremely harmful to the electrolytic deposition process of zinc, and the excessive content of the impurities can reduce the electrolytic current efficiency and influence the quality of cathode zinc. Therefore, all impurities that are detrimental to zinc electrowinning must be removed by solution purification, which yields a qualified zinc sulfate solution.

The purification of zinc sulfate solution usually adopts zinc powder adding displacement method, and is assisted by adding additives, including zinc powder-arsenic salt method, zinc powder-antimony salt method, alloy zinc powder method and other purification methods. In the actual production process, according to different requirements of various impurity elements to be removed on temperature, the purification process is divided into two or more sections, the purification time is more than 2.5 hours, wherein the integral temperature of the zinc sulfate solution in at least one section of high-temperature impurity removal process needs to be maintained at more than 78 ℃, and the time is at least 1-2 hours.

In the existing purification operation, electric furnace zinc powder (or metal zinc powder) under the condition of normal temperature (room temperature) is added into a zinc sulfate solution, or the zinc powder is simply made into high pulp by using liquid and then added into the zinc sulfate solution. The added zinc powder absorbs the heat of the solution, so that the surface temperature reaches the thermodynamic condition of the reaction and then the replacement reaction starts to occur. In the heat absorption-heat transfer process, the temperature inside the zinc powder is slowly increased to be balanced with the temperature of the solution, in the temperature balancing process, a reaction interface is in a low-temperature stage, the replacement reaction is slow, the zinc powder rapidly reacts with acid in the solution to cause the pH value on the surface of the zinc powder to be rapidly increased, hydroxide is formed to wrap the zinc powder, and the electronic transfer in the replacement process is blocked. Therefore, the traditional zinc sulfate solution purification process has the problems of low utilization efficiency of zinc powder, large consumption of zinc powder (generally, the addition amount is 3-5 times or even higher than the total mass of copper, cadmium, cobalt and nickel), strict temperature condition of the zinc sulfate solution, more than two times of liquid-solid separation required in the process, large energy consumption in the whole production process and high production cost. Therefore, the purification method of zinc sulfate solution is to be further improved.

The invention aims to overcome the defects in the prior art and provide a method for intensively purifying a zinc sulfate solution, which is a zinc sulfate solution purification method with simple process flow, easy implementation, reduced energy consumption and comprehensive realization of economic benefits and environmental benefits.

Disclosure of Invention

In order to solve the above problems, the present inventors have conducted intensive studies and provided a method for enhanced purification of at least one metal impurity of copper, cadmium, cobalt, nickel, arsenic, antimony, etc. in a zinc sulfate solution, comprising injecting zinc powder into the zinc sulfate solution by means of a pressurized device, using a non-oxidizing gas as a protective medium and a pressurized medium, in a jet flow manner, to perform purification treatment, and performing ultrasonic enhancement treatment during the treatment process to obtain a qualified purified zinc sulfate solution. The method for purifying the zinc sulfate solution can obviously reduce the consumption of zinc powder and the temperature of the zinc sulfate solution, shorten the purification time, and save the purification power consumption and energy consumption, thereby obviously reducing the treatment cost and avoiding the deterioration of the operation environment, and the invention is completed.

The invention aims to provide the following technical scheme:

(1) the method for strengthening and purifying the zinc sulfate solution comprises the step of strengthening and purifying the zinc sulfate solution by applying ultrasonic waves to a reaction system in the zinc powder purifying process.

(2) According to the method in the above (1), the particle size of the zinc powder is 0.08-0.4 mm, preferably 0.12-0.18 mm;

the ultrasonic frequency is 20 kHz;

the ultrasonic power is 100W to 3000W, preferably 500W to 2500W.

(3) The method according to (1) above, further comprising introducing zinc powder into the zinc sulfate solution in the form of a spray stream to effect zinc sulfate solution purification.

The method for intensively purifying the zinc sulfate solution provided by the invention has the following beneficial effects:

(1) according to the invention, zinc powder is added into a sulfuric acid aqueous solution, an ultrasonic device is started, and the cavitation effect, mechanical effect and thermal effect of ultrasonic waves can form local high temperature and high pressure in the solution and are accompanied by jet flow, so that the updating and disturbance of a phase interface and a homogeneous phase interface can be promoted to form the cavitation effect of bubbles or cavities, hydroxide formed in the purification and impurity removal process of the zinc powder can be prevented from depositing and wrapping on the surface of the zinc powder, the passivation of the zinc powder is avoided or reduced, the diffusion of zinc ions into the solution is accelerated, the electron transfer in the replacement process is promoted, the replacement reaction is accelerated, the purification and impurity removal process of the zinc powder is promoted.

(2) The method comprises the steps of introducing zinc powder into a zinc sulfate solution in a pressurized jet flow mode for purification reaction, and damaging coating hydroxides formed on the surface of the zinc powder by friction with solid particles and liquid to expose fresh surfaces to promote replacement reaction.

(3) The method can also comprise the step of adding the zinc powder into the zinc sulfate solution in the form of high-temperature zinc powder, the problem of zinc powder agglomeration can be effectively solved by the high-temperature zinc powder, and the method has long-term development in the aspects of improving the reaction efficiency, reducing the usage amount of the zinc powder, improving the impurity residue grade and the like.

(4) The method of the invention adopts hot-pressed zinc powder to purify the zinc sulfate solution, the consumption of the zinc powder is greatly reduced compared with the prior art, the treatment time is obviously shortened, the slag amount is greatly reduced, the increase of the temperature of the whole zinc sulfate solution is avoided, the energy consumption in the production process is reduced, and the improvement of economic benefit and environmental benefit is comprehensively realized.

Drawings

Fig. 1 shows a flow chart of the reinforced purification of zinc sulfate solution provided by the invention.

Detailed Description

The features and advantages of the present invention will become more apparent and appreciated from the following detailed description of the invention.

In the leaching process of zinc sulfate, most of the metal impurities entering the solution are removed from the solution along with the neutralization hydrolysis during leaching, but a part of the impurities remain in the solution, mainly copper (Cu), cadmium (Cd), nickel (Ni), which have a redox potential greater than that of zinc, and a small amount of cobalt (Co), arsenic (As), antimony (Sb), germanium (Ge), and the like. The presence of these impurities not only poses a great hazard to the zinc electrowinning process, but also makes it absolutely necessary to separate them from the overall resources. Therefore, the neutral leachate obtained in the leaching process is purified. The purification is a process of removing impurities in the neutral supernatant after leaching and filtration to a predetermined limit or less to increase the purity thereof so as to satisfy the requirement of the leachate in the electrodeposition.

In the present invention, the redox potential is a relative value, which is 1X 10⁵The potential difference between the platinum sheet saturated with hydrogen gas in pa and the hydrogen ion solution having a concentration of 1 mol/liter is specified to be zero, that is, the equilibrium potential of the following reduction reactions is specified to be equal to zero:

in the present invention, the leachate satisfying the electrolytic deposition, i.e. the qualified leachate, includes but is not limited to the following conditions: the copper content is lower than 0.2 mg/L; the cadmium content is lower than 0.3 mg/L; the cobalt content is lower than 0.8 mg/L; the content of nickel is lower than 0.1 mg/L; the arsenic content is lower than 0.001 mg/L; the content of antimony is less than 0.002 mg/L.

The present inventors have conducted extensive studies on the purification process of a leaching solution, and found that zinc powder charged into the leaching solution can react with hydrogen having a larger oxidation-reduction potential to produce insoluble hydroxides on the surface of the zinc powder; and because the temperature of the added zinc powder is low, heat absorption is needed to achieve the thermodynamic conditions of the reaction, and then the replacement reaction begins to occur; in the heat transfer process, the temperature of the solution in the zinc powder is slowly increased to be balanced with the temperature of the solution, and in the temperature balancing process, a reaction interface is in a low-temperature stage, the replacement reaction is slow, so that the zinc powder is further promoted to rapidly react with acid in the solution to rapidly increase the pH value on the surface of the zinc powder, the zinc powder is wrapped by hydroxide, and the purification reaction efficiency is reduced.

In order to solve the problems, the invention provides a method for strengthening and purifying a zinc sulfate solution, which comprises the step of strengthening and purifying the zinc sulfate solution by applying ultrasonic waves to a reaction system in the process of purifying the zinc sulfate solution by using zinc powder.

In the invention, the zinc sulfate solution is leachate of zinc hydrometallurgy or zinc sulfate solution with pH of 4.5-5.4.

In the invention, the particle size of the zinc powder is 0.08-0.4 mm, preferably 0.12-0.18 mm. From the viewpoint of increasing the specific surface to accelerate the substitution reaction, it is naturally better that the particle size of the zinc powder is smaller, but if it is too small, it will cause it to float on the surface of the solution, and it is apparently not favorable for the effective use of the zinc powder. The inventor finds that when the particle size is 0.08-0.4 mm, particularly 0.12-0.18 mm, the zinc powder can be suspended in a zinc sulfate solution to be treated and is surrounded by liquid, the reaction efficiency of the zinc powder is high, and the reaction requirement can be met.

In the invention, the addition of ultrasonic waves can effectively inhibit the generation of hydroxide on the surface of zinc powder in the reaction process and strengthen the purification process. The reason is mainly due to the cavitation effect of the ultrasonic waves, when the ultrasonic waves act on the liquid, a large amount of small bubbles can be generated, the small bubbles can continuously move, grow or be suddenly broken along with the vibration of the surrounding medium, and when the small bubbles are broken, the surrounding liquid suddenly rushes into the bubbles to generate high temperature and high pressure and simultaneously generate shock waves; the heat, pressure and particle-assisted collisions generated by this cavitation effect can effectively renew the particle surface. Meanwhile, the ultrasonic wave also has (1) mechanical effect: the mechanical action of the ultrasonic wave can promote the dispersion of the solid, so that the non-uniform reaction of the zinc powder in the system is avoided, and the process of replacement and impurity removal is integrally accelerated; (2) thermal effect: because the ultrasonic frequency is high and the energy is large, the ultrasonic wave can generate obvious thermal effect when being absorbed by liquid medium, and the displacement reaction is promoted to be carried out.