Method for separating and recovering nano-zinc oxide from zinc-containing solution through complexing-ammonia distillation

Abstract

The invention discloses a method for separating and recovering nano-zinc oxide from a zinc-containing solution through complexing-ammonia distillation, and belongs to the field of hydrometallurgy. According to the method, zinc-ammonia complexing is utilized, firstly, impurity ions with low precipitation pH are removed by adjusting the pH value of a solution, then the pH value of the solution is reduced in a heating ammonia distillation mode, and zinc ion precipitation is separated out, so that the zinc ion precipitation is separated from impurity ions with high precipitation pH in the solution, high-purity zinc-containing precipitation is obtained, and finally high-purity nano zinc oxide is obtained through low-temperature roasting. The obtained zinc extraction tailings can be roasted to prepare the NH3-SCR catalyst with excellent performance, a calcium-magnesium-containing solution can be used for CO2 mineralization, and full-quantitative utilization of impurity ions is achieved. According to the method, separation of zinc and impurity ions in the zinc-containing solution can be achieved, the nano-zinc oxide product is obtained, the purity of the nano-zinc oxide product is as high as 97.2%, and the zinc recovery rate reaches 95%. The method realizes the purpose of separating, purifying and preparing the high-purity zinc oxide in the complex solution, has the characteristics of simple process, environment friendliness and low cost, and has wide application prospect and practical significance.

Description

Technical Field

[0001] The invention relates to the field of hydrometallurgy, and in particular to a method for separating and recovering nano zinc oxide from a zinc-containing solution by complexing and ammonia evaporation. Background Art

[0002] Zinc is the third largest nonferrous metal widely used in important areas of national development such as steel corrosion protection, energy and magnetic materials, and can be alloyed with a variety of metals. China is the world's largest zinc producer and consumer, with an annual output of about 5.6 million tons, but it still relies heavily on imported zinc ore resources, which has severely restricted domestic zinc metal smelting. Adjusting the structure of the zinc industry chain, strengthening industry technological innovation, improving the comprehensive utilization of secondary resources, and improving product quality are the inevitable trends in the development of my country's zinc industry.

[0003] At present, about 80% of the world's zinc is extracted from zinc ore through the hydrometallurgical process, and the remaining 20% ​​comes from the recycling of secondary zinc resources. In the traditional hydrometallurgical process, sphalerite is roasted at 930℃-980℃ to obtain zinc containing mainly ZnO and Fe. 2 O 3 Then, the roasted slag is leached with dilute sulfuric acid (waste electrolyte) to obtain zinc sulfate solution, and then zinc is extracted through subsequent purification and electrodeposition processes.

[0004] However, for the extraction process of zinc from zinc-containing secondary resources, the mainstream process is the pyrometallurgical high-temperature reduction process, which requires high temperature, a large amount of carbonaceous reducing agent and huge equipment investment, resulting in its wide application being limited, and its product is basically a crude product, which still needs further treatment or purification to obtain high-purity zinc-containing compounds or metallic zinc. At the same time, the addition of carbonaceous reducing agents will also bring about the problem of carbon emissions. In addition, the wet zinc extraction process has the advantages of simple equipment, low investment, and high grade of zinc-containing products, which is suitable for extracting low-grade zinc-containing resources. However, the zinc ion content in the leachate of the hydrometallurgical process is low, and the impurity ion content is high. Direct use as an electrolytic zinc raw material will result in a large load and cumbersome process for the traditional purification and impurity removal steps, which greatly increases the production cost. CN112125327B discloses a process for preparing active zinc oxide, which comprises placing zinc-containing smoke into a solution containing ammonium carbonate, ammonia water and an organic solvent for ultrasonic leaching, adding a reaction accelerator after centrifugation, and obtaining basic zinc carbonate by microwave heating, and then washing and drying the basic zinc carbonate with ammonia water and tetrachloromethane. The process is complicated, the cost is high, and there is also the problem of pollution from organic reagents.

[0005] Therefore, how to efficiently separate zinc from the wet zinc extraction solution of secondary zinc-containing resources and produce a high-purity product is one of the key technical issues that need to be urgently solved in this field. Summary of the invention

[0006] To solve the above problems, the present invention provides a method for separating and recovering nano zinc oxide from a zinc-containing solution by complexing and ammonia evaporation. The method simplifies the complex purification process of the leaching solution in the traditional wet zinc extraction process, realizes the full quantitative utilization of impurity ions, and obtains a high-purity nano zinc oxide product.

[0007] The method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation of the present invention specifically comprises the following steps:

[0008] S1, adding ammonia water to the zinc-containing solution to adjust to a certain pH, stirring for a certain period of time, and separating the solid and liquid by suction filtration to obtain zinc extraction tailings and zinc ammonia solution;

[0009] S2, heating the zinc-ammonia solution at a certain temperature and keeping it warm for a certain time, separating the solid and the liquid by suction filtration to obtain a zinc-containing precipitate and a calcium-magnesium-containing solution.

[0010] S3, calcining the zinc-containing precipitate at a certain temperature for a certain time to obtain nano zinc oxide.

[0011] Furthermore, the pH is 9-11, and the stirring time is 10-120 min.

[0012] Furthermore, the S1 also includes an auxiliary agent, and the auxiliary agent is ammonium sulfate or ammonium carbonate.

[0013] Furthermore, the molar ratio of the auxiliary agent to the zinc ion is (0.1-3):1.

[0014] Furthermore, the heating temperature is 40-100° C., and the heating time is 1-5 h.

[0015] Furthermore, the calcination temperature is 300-600° C., and the calcination time is 0.5-3 h.

[0016] Compared with the prior art, the beneficial technical effects of the present invention are:

[0017] The invention can achieve the purpose of efficiently extracting and separating zinc from a zinc-containing solution, with a zinc recovery rate of up to 95%, and obtain a nano zinc oxide product with a purity of up to 97.2%, which can achieve full quantitative utilization of impurity ions, and the zinc extraction tailings can be roasted to obtain NH 3 -SCR catalyst, calcium and magnesium solution can be used for CO 2 Mineralization.

[0018] The present invention uses zinc-ammonia complexation under mild conditions to first remove impurity ions (such as iron and manganese ions) with a lower precipitation pH in the solution through precipitation, then heats and evaporates ammonia to reduce the solution pH, precipitates zinc ions, and separates them from impurity ions (such as calcium and magnesium ions) with a higher precipitation pH in the solution to obtain a high-purity zinc-containing precipitate, and finally obtains high-purity nano zinc oxide through roasting.

[0019] The ammonia water used in the present invention, including ammonium sulfate and ammonium carbonate additives, can be recycled through absorption, crystallization and other means, with low cost and excellent effect.

[0020] The present invention realizes the full-quantity resource utilization of zinc-containing solution and is a new method for efficiently disposing and utilizing zinc-containing solution. It not only realizes the resource utilization of zinc-containing secondary resources, but also helps to alleviate the pollution problem of zinc-containing wastewater in industrial production and increase the production channels of recycled zinc. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] Figure 1 The process flow chart of the present invention for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation;

[0023] Figure 2 These are the XRD and SEM images of the zinc-containing precipitate and nano zinc oxide produced in Example 6 of the present invention. DETAILED DESCRIPTION

[0024] The present invention provides a method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation, which specifically comprises the following steps:

[0025] S1, adding ammonia water to the zinc-containing solution to adjust to a certain pH, stirring for a certain period of time, and separating the solid and liquid by suction filtration to obtain zinc extraction tailings and zinc ammonia solution;

[0026] S2, heating the zinc-ammonia solution at a certain temperature and keeping it warm for a certain time, separating the solid and the liquid by suction filtration to obtain a zinc-containing precipitate and a calcium-magnesium-containing solution.

[0027] S3, calcining the zinc-containing precipitate at a certain temperature for a certain time to obtain nano zinc oxide.

[0028] In one embodiment, the pH is 9-11, and the stirring time is 10-120 min.

[0029] In one embodiment, the S1 further includes an auxiliary agent, and the auxiliary agent is ammonium sulfate or ammonium carbonate.

[0030] In one embodiment, the molar ratio of the auxiliary agent to the zinc ion is (0.1-3):1.

[0031] In one embodiment, the heating temperature is 40-100° C., and the heating time is 1-5 hours.

[0032] In one embodiment, the calcination temperature is 300-600° C., and the calcination time is 0.5-3 h.

[0033] The technical solution provided by the present invention is further described below in conjunction with embodiments.

[0034] The zinc-containing solution used in the specific method of the present invention is a leaching solution of electric furnace dust sulfation roasting, and its composition is shown in Table 1, wherein the anion is sulfate.

[0035] Table 1 Chemical composition of zinc-containing solution (g / L)

[0036]

[0037] Example 1

[0038] A method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation, the steps are as follows:

[0039] S1, adding ammonia water to the zinc-containing solution to adjust the pH to 9, stirring for 30 minutes, separating the solid and liquid by suction filtration to obtain zinc extraction tailings and zinc ammonia solution, at which the zinc extraction rate is 14.3%;

[0040] S2, heating the zinc-ammonia solution at 80° C. and keeping it warm for 1.5 h, separating the solid and the liquid by suction filtration to obtain a zinc-containing precipitate and a calcium-magnesium-containing solution, at which the zinc yield is 52.8%;

[0041] S3, calcining the zinc-containing precipitate at 300° C. for 1 hour to obtain nano zinc oxide, at which the purity of the zinc oxide is 85.3%.

[0042] Example 2

[0043] A method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation, the steps are as follows:

[0044] S1, adding ammonia water to the zinc-containing solution to adjust the pH to 10, stirring for 60 minutes, and separating the solid and liquid by suction filtration to obtain zinc extraction tailings and zinc ammonia solution. At this time, the zinc extraction rate is 82.9%;

[0045] S2, heating the zinc-ammonia solution at 60° C. and keeping it warm for 3 h, separating the solid and liquid by suction filtration to obtain a zinc-containing precipitate and a calcium-magnesium-containing solution, at which the zinc yield is 66.2%;

[0046] S3, calcining the zinc-containing precipitate at 400° C. for 0.5 h to obtain nano zinc oxide, at which the purity of the zinc oxide is 87.8%.

[0047] Example 3

[0048] A method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation, the steps are as follows:

[0049] S1, adding ammonia water to the zinc-containing solution to adjust the pH to 10, adding ammonium sulfate in a molar ratio of 0.2:1 to zinc ions, stirring for 30 minutes, separating the solid and liquid by suction filtration to obtain zinc extraction tailings and zinc ammonia solution, at which the zinc extraction rate is 87.2%;

[0050] S2, heating the zinc-ammonia solution at 70° C. and keeping it warm for 1.5 h, separating the solid and the liquid by suction filtration to obtain a zinc-containing precipitate and a calcium-magnesium-containing solution, at which the zinc yield is 85.3%;

[0051] S3, calcining the zinc-containing precipitate at 400° C. for 3 hours to obtain nano zinc oxide, at which the purity of the zinc oxide is 83.7%.

[0052] Example 4

[0053] A method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation, the steps are as follows:

[0054] S1, adding ammonia water to the zinc-containing solution to adjust the pH to 10, adding ammonium sulfate in a molar ratio of 1.5:1 to zinc ions, stirring for 30 minutes, separating the solid and liquid by suction filtration to obtain zinc extraction tailings and zinc ammonia solution, at which the zinc extraction rate is 99.8%;

[0055] S2, heating the zinc-ammonia solution at 80° C. and keeping it warm for 2.5 h, separating the solid and the liquid by suction filtration to obtain a zinc-containing precipitate and a calcium-magnesium-containing solution, at which the zinc yield is 95.2%;

[0056] S3, calcining the zinc-containing precipitate at 500° C. for 1 hour to obtain nano zinc oxide, at which the purity of the zinc oxide is 83.3%.

[0057] Example 5

[0058] A method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation, the steps are as follows:

[0059] S1, adding ammonia water to the zinc-containing solution to adjust the pH to 10, adding ammonium carbonate in a molar ratio of 1.5:1 to zinc ions, stirring for 30 minutes, separating the solid and liquid by suction filtration to obtain zinc extraction tailings and zinc ammonia solution, at which the zinc recovery rate is 99.8%;

[0060] S2, heating the zinc-ammonia solution at 80° C. and keeping it warm for 4 hours, separating the solid and the liquid by suction filtration to obtain a zinc-containing precipitate and a calcium-magnesium-containing solution, at which the zinc extraction rate is 91.4%;

[0061] S3, calcining the zinc-containing precipitate at 300° C. for 1 hour to obtain nano zinc oxide, at which the purity of the zinc oxide is 90.7%.

[0062] Example 6

[0063] A method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation, the steps are as follows:

[0064] S1, adding ammonia water to the zinc-containing solution to adjust the pH to 10, adding ammonium carbonate in a molar ratio of 0.75:1 to zinc ions, stirring for 30 minutes, separating the solid and liquid by suction filtration to obtain zinc extraction tailings and zinc ammonia solution, at which the zinc recovery rate is 99.8%;

[0065] S2, heating the zinc-ammonia solution at 80° C. and keeping it warm for 2.5 hours, separating the solid and the liquid by suction filtration to obtain a zinc-containing precipitate and a calcium-magnesium-containing solution, at which the zinc extraction rate is 95%;

[0066] S3, calcining the zinc-containing precipitate at 500° C. for 1 hour to obtain nano zinc oxide, at which the purity of the zinc oxide is 97.2%.

[0067] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation and ammonia evaporation, characterized in that: The following steps are involved: S1, adding ammonia water to the zinc-containing solution to adjust to a certain pH, stirring for a certain period of time, and separating the solid and liquid by suction filtration to obtain zinc extraction tailings and zinc ammonia solution; S2, heating the zinc-ammonia solution at a certain temperature and keeping it warm for a certain time, separating the solid and the liquid by suction filtration to obtain a zinc-containing precipitate and a calcium-magnesium-containing solution. S3, calcining the zinc-containing precipitate at a certain temperature for a certain time to obtain nano zinc oxide.

2. The method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation according to claim 1, characterized in that: The pH is 9-11, and the stirring time is 10-120 min.

3. The method for separating and recovering nano zinc oxide from a zinc-containing solution by complexing and ammonia evaporation according to claim 1, characterized in that: The S1 also includes an auxiliary agent, which is ammonium sulfate or ammonium carbonate.

4. The method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation according to claim 1, characterized in that: The molar ratio of the auxiliary agent to the zinc ion is (0.1-3):

1.

5. The method for separating and recovering nano zinc oxide from a zinc-containing solution by complexing and ammonia evaporation according to claim 1, characterized in that: The heating temperature is 40-100° C., and the heating time is 1-5 hours.

6. The method for separating and recovering nano zinc oxide from a zinc-containing solution by complexation-ammonia evaporation according to claim 1, characterized in that: The calcination temperature is 300-600° C., and the calcination time is 0.5-3 hours.

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