Method for recovering zinc from industrial acidic wastewater

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a method for recovering zinc from industrial acid wastewater. The method comprises the following specific steps: sulfur concentrate activation: grinding, acid leaching, washing and drying blocky sulfur concentrate in sequence for later use; selective recovery of zinc: taking a certain amount of zinc-containing industrial acidic wastewater, adding the treated sulfur concentrate into the zinc-containing industrial acidic wastewater, and uniformly stirring to obtain mixed slurry; and solid-liquid separation is conducted, specifically, a certain amount of flocculating agent is added into the obtained mixed slurry for solid-liquid separation, and supernate and zinc-containing concentrate are obtained. The zinc grade in the zinc-containing concentrate is not lower than 10%, and the zinc-containing concentrate can be sold as zinc concentrate after simple flotation. The method has the advantages of simple and easy process, low equipment requirement, convenience in operation, wide application range and the like, and has good social benefits and economic values.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a method for recovering zinc from industrial acidic wastewater, in particular to a method for realizing green, efficient and low-cost recovery of zinc from wastewater by mechanically activating sulfur concentrate. Background Art

[0002] Zinc is an important essential trace element in the human body. A normal adult contains about 2-3g of zinc, which is distributed in various tissues and organs. Zinc has a variety of biological functions, such as catalytic function, structural function and regulatory function. It also participates in the metabolism of carbohydrates, proteins, lipids and nucleic acids, and plays an important role in maintaining the physiological functions and normal metabolism of the body. Zinc deficiency can cause a variety of related diseases, such as loss of appetite, intellectual impairment, delayed wound healing, neurosensory disorders, etc. On the contrary, excessive zinc can also cause toxicity to the human body and lead to protein dysfunction. Therefore, maintaining the dynamic balance of zinc in the body is crucial to human health. In recent years, due to the intensification of human activities such as mining, smelting and processing, a large amount of zinc has been discharged into the environment, exceeding the self-purification capacity of nature, causing serious harm to the human body, animals and plants. Therefore, in order to realize the recycling of zinc in wastewater and reduce its harm to the environment, zinc-containing wastewater must be effectively treated. The current common treatment methods include precipitation, adsorption, reverse osmosis, ion exchange, etc., but these methods all have certain defects, such as residual agents, high cost and the risk of secondary pollution. Therefore, it is necessary to develop a completely new method for recovering zinc without secondary pollution.

[0003] Sulfur concentrate is mainly composed of pyrite, which is the most widely distributed sulfide ore in nature. At the same time, sulfur concentrate is one of the important chemical products in the chemical industry and an important chemical raw material. Its main use is to manufacture sulfuric acid and fertilizers. my country's sulfur concentrate resources are extremely rich. It is of great significance to make full use of this resource and increase its added value. In recent years, people have gradually discovered that sulfur concentrate has good application prospects in the field of wastewater treatment. Summary of the invention

[0004] The present invention discloses a method for recovering zinc from industrial acidic wastewater to solve any of the above and other potential problems in the prior art.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] A method for recovering zinc from industrial acidic wastewater, the method specifically comprising the following steps:

[0007] S1) Activation of sulfur concentrate: grinding, acid leaching, washing and drying the lump sulfur concentrate in order to achieve the purpose of activation;

[0008] S2) Selective recovery of zinc: take a certain amount of zinc-containing industrial acidic wastewater, add an appropriate amount of sulfur concentrate obtained in S1) and stir;

[0009] S3) solid-liquid separation: adding a flocculant to the mixed slurry obtained in S2) to perform solid-liquid separation to obtain a supernatant and a zinc-containing concentrate.

[0010] Furthermore, the grinding conditions in S1) are as follows: mechanical ball milling is used, water twice the mass of the sulfur concentrate is added as a dispersion medium, and grinding is performed for 4 hours.

[0011] Furthermore, the sulfur concentrate in S1) is ground to 150-200 mesh.

[0012] Furthermore, the acid leaching conditions in S1) are: using 1 mol / L dilute hydrochloric acid and accelerating the reaction with ultrasound for 20 to 40 minutes.

[0013] Furthermore, the washing conditions in S1) are: using anhydrous ethanol and rinsing 2 to 3 times.

[0014] Furthermore, the drying conditions in S1) are: using a vacuum drying oven at a temperature of 200-400°C.

[0015] Furthermore, the pH value of the zinc-containing acidic wastewater in S1) is 1-5, and the zinc concentration in the zinc-containing acidic wastewater is not less than 100 mg / L.

[0016] Furthermore, the specific process parameters for recovering zinc in S2) are:

[0017] The ratio of the molar amount of sulfur concentrate to the molar amount of zinc ion is 0.8:1 to 1.2:1;

[0018] The stirring speed is 100-800 r / min, and the stirring time is 30-60 min.

[0019] Furthermore, the process parameters of the solid-liquid separation in S3) are:

[0020] The reaction temperature is room temperature;

[0021] The amount of the coagulant added is such that the volume ratio of the coagulant to the zinc-containing wastewater is 2:1000 to 6:1000;

[0022] The standing time is 1 to 60 minutes.

[0023] Furthermore, the coagulant is one or a combination of polyacrylamide, sodium polyacrylate and polyvinyl alcohol.

[0024] Compared with the traditional method of using sodium sulfide or sodium hydrosulfide as a reagent for recovering zinc, the technical solution of the present invention has the following advantages:

[0025] 1. The present invention uses cheaper and more common sulfur concentrate, which greatly reduces the cost of zinc recovery;

[0026] 2. The present invention adopts more common sulfur concentrate, realizes the high value of sulfur concentrate and improves its added value;

[0027] 3. The present invention uses powdered sulfur concentrate as a reagent, which can effectively avoid the defects such as air pollution caused by traditional methods;

[0028] 4. The present invention is easy to industrialize, simple to operate, and close to the existing processing technology of various enterprises.

[0029] The present invention adopts a combination of "mechanical activation" and "ultrasonic activation" to effectively improve the reaction activity of sulfur concentrate, selectively recover zinc ions in zinc-containing acidic wastewater, greatly improve the grade of zinc in sulfur concentrate, and can be sold as zinc concentrate directly or through simple flotation, which not only removes zinc ions in wastewater, but also generates economic benefits and avoids the secondary pollution problem (air pollution) caused by the previous method. The present invention adopts a combination of "mechanical activation" and "ultrasonic activation" and has the advantages of simple process, low equipment requirements, convenient operation, wide environmental protection adaptability, etc., and has good social benefits and economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a flowchart of a method for recovering zinc from industrial acidic wastewater. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below in conjunction with specific embodiments, but the scope of protection claimed is not limited to the embodiments.

[0032] like Figure 1 As shown, the present invention provides a method for recovering zinc from industrial acidic wastewater, the method specifically comprising the following steps:

[0033] S1) Activation of sulfur concentrate: grinding, acid leaching, washing and drying the lump sulfur concentrate in sequence for standby use;

[0034] S2) Selective recovery of zinc: taking a certain amount of zinc-containing industrial acidic wastewater, adding the sulfur concentrate treated by S1) into the zinc industrial acidic wastewater and stirring evenly to obtain a mixed slurry;

[0035] S3) solid-liquid separation: adding a certain amount of flocculant to the mixed slurry obtained in S2) to perform solid-liquid separation to obtain a supernatant and a zinc-containing concentrate.

[0036] Preferably, the grinding conditions in S1) are: using mechanical ball milling, adding water twice the mass of sulfur concentrate as a dispersion medium, grinding for at least 4 hours, and grinding to 150-200 mesh;

[0037] The acid leaching conditions are: using 1 mol / L dilute hydrochloric acid and using ultrasound to accelerate the reaction, and reacting for 20 to 40 minutes;

[0038] The washing conditions are: using anhydrous ethanol and rinsing 2 to 3 times.

[0039] The drying conditions are: using a vacuum drying oven at a temperature of 200-400°C.

[0040] Preferably, the sulfur concentrate is at least one of pyrite, pyrrhotite and pyrite.

[0041] Preferably, the specific process parameters for recovering zinc in S2) are:

[0042] The ratio of the molar amount of sulfur concentrate to the molar amount of zinc ions in the zinc-containing industrial acidic wastewater is 0.8:1 to 1:1;

[0043] The stirring speed is 100-800 r / min, and the stirring time is 30-60 min.

[0044] Preferably, the pH value of the zinc-containing industrial acidic wastewater in S2) is 1-5.

[0045] Preferably, the concentration of zinc in the industrial acidic wastewater in S2) is not less than 100 mg / L.

[0046] Preferably, the process parameters for solid-liquid separation in S3) are:

[0047] The reaction temperature is room temperature;

[0048] The amount of the coagulant added is such that the volume ratio of the coagulant to the zinc-containing wastewater is 2:1000 to 6:1000;

[0049] The standing time is 1 to 60 minutes.

[0050] Preferably, the coagulant is one or a combination of polyacrylamide, sodium polyacrylate and polyvinyl alcohol.

[0051] Preferably, the zinc grade of the zinc-containing concentrate in S3) is not less than 10%.

[0052] A zinc-containing concentrate is prepared by the above method.

[0053] Implementation Case 1:

[0054] Take 1L of acidic zinc-containing wastewater from a mining area of ​​a mine with a zinc concentration of 580mg / L. First add lime milk to adjust the pH value to 5, then separate the solid and liquid to obtain a precipitate and a supernatant. Then add 2000mg of activated sulfur concentrate to the supernatant, stir at a speed of 300r / min, react at room temperature for 30min, then stand for 5min, filter to obtain a zinc-containing precipitate and a supernatant. The zinc grade in the zinc-containing precipitate is 26% after testing.

[0055] Implementation Case 2:

[0056] Take 1L of acidic zinc-containing wastewater from a zinc smelting enterprise with a zinc concentration of 417mg / L, add 1500mg of activated ALCOHOL, stir at a speed of 400r / min, react at room temperature for 45min, then stand for 10min, filter to obtain zinc-containing precipitate and supernatant. The zinc grade in the zinc-containing precipitate is 24% after testing.

[0057] The above is a detailed introduction to a method for recovering zinc from industrial acidic wastewater provided in the embodiment of the present application. The description of the above embodiment is only used to help understand the method and its core idea of ​​the present application; at the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present application.

[0058] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. As mentioned throughout the specification and claims, "including" and "comprising" are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be determined by the definition of the attached claims.

[0059] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0060] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

Claims

1. A method for recovering zinc from industrial acidic wastewater, characterized in that: The method specifically comprises the following steps: S1) Activation of sulfur concentrate: grinding, acid leaching, washing and drying the lump sulfur concentrate in sequence for standby use; S2) Selective recovery of zinc: taking a certain amount of zinc-containing industrial acidic wastewater, adding the sulfur concentrate treated by S1) into the zinc industrial acidic wastewater and stirring evenly to obtain a mixed slurry; S3) solid-liquid separation: adding a certain amount of flocculant to the mixed slurry obtained in S2) to perform solid-liquid separation to obtain a supernatant and a zinc-containing concentrate.

2. The method according to claim 1, characterized in that The grinding conditions in S1) are as follows: using a mechanical ball mill, adding water twice the mass of the sulfur concentrate as a dispersion medium, grinding for at least 4 hours, and grinding to 150-200 mesh; The acid leaching conditions are: using 1 mol / L dilute hydrochloric acid and using ultrasound to accelerate the reaction, and reacting for 20 to 40 minutes; The washing conditions are: using anhydrous ethanol, washing 2 to 3 times; The drying conditions are: using a vacuum drying oven at a temperature of 200-400°C.

3. The method according to claim 1, characterized in that The sulfur concentrate is at least one of pyrite, pyrrhotite and pyrite.

4. The method according to claim 1, characterized in that: The specific process parameters for recovering zinc in S2) are: The ratio of the molar amount of sulfur concentrate to the molar amount of zinc ions in the zinc-containing industrial acidic wastewater is 0.8:1 to 1:1; The stirring speed is 100-800 r / min, and the stirring time is 30-60 min.

5. The method according to claim 1, characterized in that: The pH value of the zinc-containing industrial acidic wastewater in S2) is 1-5.

6. The method according to claim 1, characterized in that The concentration of zinc in the industrial acidic wastewater in S2) is not less than 100 mg / L.

7. The method according to claim 1, characterized in that The process parameters of the solid-liquid separation in S3) are: The reaction temperature is room temperature; The amount of the coagulant added is such that the volume ratio of the coagulant to the zinc-containing wastewater is 2:1000 to 6:1000; The standing time is 1 to 60 minutes.

8. The method according to claim 1, characterized in that: The coagulant is one or a combination of polyacrylamide, sodium polyacrylate and polyvinyl alcohol.

9. The method according to claim 1, characterized in that: The zinc grade of the zinc-containing concentrate in S3) is not less than 10%.

10. A zinc-containing concentrate, characterized in that: The zinc-containing concentrate is prepared by the method according to any one of claims 1 to 9.

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