A method for separating and extracting nickel from high-concentration copper-arsenic wastewater

Abstract

The application discloses a method for separating and extracting nickel from high-concentration copper-arsenic wastewater, which comprises the following steps: firstly, performing first membrane separation treatment on the acidic high-copper-arsenic wastewater to obtain antimony-bismuth-removed wastewater; secondly, performing second membrane separation treatment on the antimony-bismuth-removed wastewater to obtain acid-removed residue; thirdly, performing neutralization treatment on the acid-removed residue to obtain a post-settled liquid; fourthly, performing ion exchange resin adsorption treatment on the post-settled liquid to obtain high-nickel waste liquid; and finally, adding sodium hydroxide into the high-nickel waste liquid to precipitate nickel ions into nickel hydroxide, and then performing filtration and drying to obtain nickel hydroxide products. The method combines the membrane separation method and the chemical precipitation method to extract nickel from the high-copper-arsenic wastewater, and has the advantages of simple technological process, high efficiency in separating copper-arsenic ions from nickel ions, and the like. The purity of the recovered nickel hydroxide is not less than 99%, the recovery rate of the nickel is not less than 85%, no excessive chemical substances are needed, no arsenic-containing hazardous waste is generated, the loss of copper and nickel elements can be minimized, and the environment is not polluted.

Description

Technical Field

[0001] This invention relates to the field of heavy metal treatment of copper smelting wastewater, specifically to a method for separating and extracting nickel from high-concentration copper-arsenic wastewater. Background Technology

[0002] Copper smelting wastewater has a complex composition, containing not only high concentrations of arsenic, copper, and nickel ions, but also certain concentrations of antimony, bismuth, and other ions. The concentrations of copper and arsenic ions are as high as 40-70 g / L, while the concentrations of antimony and bismuth ions are low and difficult to separate. Direct discharge of heavy metal ion wastewater not only has a great impact on the environment, but also causes the loss of valuable metals.

[0003] Currently, steel mills, chemical plants, dye plants, electroplating plants, and smelters mostly use chemical methods to recover metallic nickel from acidic wastewater. Chinese invention patent CN 109775899 discloses a method for recovering nickel from stainless steel pickling wastewater. This method utilizes the precipitation effect of different metal ions at different pH levels, employing a step-by-step pH adjustment method to separate iron, chromium, and fluoride ions and recover metallic nickel. However, this method does not mention the nickel recovery rate. Chinese invention patent CN 106544528 discloses a method for recovering metallic nickel from pickling wastewater. While this method can recover nickel from wastewater, the entire process is lengthy, involves a large amount of chemical input, and does not specify the purity of the produced nickel.

[0004] Therefore, it is necessary to develop a suitable technology for recovering and purifying metallic nickel from copper smelting wastewater that is simple to operate, has a high recovery rate, and minimizes the loss of nickel and nickel-containing compounds during industrial production. Summary of the Invention

[0005] To address the challenges of existing technologies, this invention aims to provide a method for extracting metallic nickel from high-copper and arsenic wastewater that requires minimal chemical input, achieves excellent separation results, and has a high recovery rate.

[0006] The technical solution of the present invention is as follows: The present invention provides a method for separating and extracting nickel from high-concentration copper-arsenic wastewater, the method specifically including the following steps:

[0007] S1) Trace metal ion retention: The acidic high copper and arsenic wastewater to be treated is subjected to the first membrane separation treatment to obtain antimony- and bismuth-free wastewater;

[0008] S2) Acid removal: The antimony-bismuth removal wastewater obtained in S1) is subjected to a second membrane separation treatment to obtain acid removal residue;

[0009] S3) Co-precipitation of copper and arsenic: The deacidified residue obtained in S3) is neutralized and filtered to obtain the precipitated liquid;

[0010] S4) Copper adsorption: The sediment obtained in S3) is treated with ion exchange resin to obtain high-nickel waste liquid.

[0011] S5) Nickel extraction: Add a certain amount of sodium hydroxide to the high-nickel waste liquid obtained in S4) to precipitate nickel ions into nickel hydroxide, filter and dry to obtain nickel hydroxide product.

[0012] The method of this invention must be strictly followed according to the above-described procedures, and the process sequence cannot be arbitrarily changed.

[0013] Furthermore, the high-concentration copper-arsenic wastewater in S1) is the mother liquor after recrystallization of copper sulfate during the copper smelting process.

[0014] Furthermore, the specific process of S1) is as follows: acidic high copper and arsenic wastewater is pumped into the first membrane separation device, the feed pressure is controlled at atmospheric pressure, and the feed temperature is 25-35℃; the first membrane material is a nanofiltration membrane.

[0015] Furthermore, the specific process of S2) is as follows: the antimony-bismuth removal wastewater is separated by a second membrane separation device, and the ratio of antimony-bismuth removal wastewater to clean water is controlled to be 1:1-1:1.5, the inlet pressure is atmospheric pressure, and the inlet temperature is 25-35℃.

[0016] The second membrane material is a porous anion exchange membrane; the porous anion exchange membrane is one or more of polyethylene, polypropylene, methyl 6-(dimethylamino)hexanoate (MDMH), and poly(2,5-dimethylphenoxy).

[0017] Furthermore, the specific process of S3) is as follows: First, the deacidification residue is passed into the first tank, and sodium hydroxide with a concentration of 32% is added to adjust the pH to 2-3. All arsenic ions and some copper ions are settled, and the solution is filtered by pressure to obtain the filtrate.

[0018] The obtained filtrate is fed into the second tank, and the pH is adjusted to 3-5. The remaining copper is then settled, filtered by pressure, and the settled liquid and filter residue are obtained. The filter residue is sent to the first tank for re-dissolution.

[0019] Furthermore, the specific process of S4 is as follows: the settled liquid is pumped into the resin exchange tower, the pH of the influent is controlled at 4-6, and copper is adsorbed by ion exchange resin to obtain high-nickel waste liquid.

[0020] Furthermore, the ion exchange resin is a chelating resin, and the chelating resin is one or more of the following ion exchange resins: IRC-86, XFS43084, XFS 4195, and IRC-748.

[0021] Furthermore, the specific process of S5 is as follows:

[0022] Add 32% sodium hydroxide to the high-nickel waste liquid to adjust the pH to 8-10, control the nickel precipitation temperature to 80-90℃, and the reaction time to 1-2 hours.

[0023] Furthermore, the method achieves a nickel recovery rate of no less than 85% and yields nickel hydroxide with a purity of no less than 99.00%.

[0024] A nickel hydroxide, wherein the nickel hydroxide is prepared by the method described above.

[0025] The present invention has the following beneficial effects:

[0026] (1) Using this method to extract nickel is simple to operate and the nickel recovery rate can reach 85%;

[0027] (2) The front end uses membrane separation to pre-separate low-concentration impurity ions such as antimony and bismuth, and then uses distribution precipitation to remove copper and arsenic ions. The resulting nickel hydroxide slag has a purity of up to 99% and a good separation effect.

[0028] (3) The entire process is simple to operate, with no excessive chemical input, and no need for subsequent purification of nickel slag, saving labor costs. Pre-separation of high-concentration acid effectively reduces the amount of sodium hydroxide used in subsequent chemical precipitation, saving costs. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating a method for separating and extracting nickel from high-concentration copper-arsenic wastewater according to the present invention. Detailed Implementation

[0030] The technical solution of the present invention will be further explained below with reference to specific implementation examples.

[0031] like Figure 1 As shown, the present invention discloses a method for separating and extracting nickel from high-concentration copper-arsenic wastewater, which specifically includes the following steps:

[0032] (1) Trace metal ion retention: High-concentration copper and arsenic wastewater is pumped into membrane separation device 1, and the feed pressure is controlled at atmospheric pressure and the feed temperature is 25-35℃. The acidic high copper and arsenic wastewater passes through membrane material 1, and trace antimony, bismuth and lead ions are retained to obtain antimony- and bismuth-free wastewater.

[0033] (2) Acid removal: Acid-containing wastewater is pumped into membrane separation device 2, and the ratio of wastewater to clean water is controlled at 1:1-1:1.5, the inlet pressure is atmospheric pressure, and the inlet temperature is 25-35℃. The antimony and bismuth removal wastewater passes through membrane material 2 to separate high concentrations of sulfate ions and hydrogen ions, and obtains deacidification residue.

[0034] (3) Co-precipitation of copper and arsenic: The deacidification residue enters the neutralization tank, sodium hydroxide is added to adjust the pH, copper and arsenic ions are precipitated, and the solution is filtered to obtain the precipitated liquid;

[0035] (4) Residual copper adsorption: Low-concentration copper is adsorbed using ion exchange resin to obtain high-nickel waste liquid;

[0036] (5) Nickel extraction: Add sodium hydroxide to adjust the pH of the wastewater to 8-9, precipitate nickel ions into nickel hydroxide, filter and dry to obtain nickel hydroxide product;

[0037] Furthermore, the high-concentration copper-arsenic wastewater is the mother liquor after recrystallization of copper sulfate during the copper smelting process. It contains high concentrations of acid, high levels of arsenic and copper ions, some nickel ions, and trace amounts of antimony, bismuth, lead, and other ions.

[0038] Furthermore, the membrane material 1 is a nanofiltration (NF) membrane;

[0039] Furthermore, the membrane material 2 is a porous anion exchange membrane, and the membrane material 2 is selected from one or more of polyethylene, polypropylene, methyl 6-(dimethylamino)hexanoate (MDMH), and poly(2,5-dimethylphenoxy).

[0040] Furthermore, the copper-arsenic co-precipitation process is carried out in two steps: first, wastewater is introduced into tank 1, 32% sodium hydroxide is added to adjust the pH to 2-3, all arsenic ions and some copper ions are precipitated, filtered, and the filtrate is introduced into tank 2. After adjusting the pH to 3-5, the remaining copper is precipitated, filtered, and the filter residue is sent to tank 1 for re-dissolution. The high-nickel waste liquid enters step (4) for the adsorption of remaining copper.

[0041] Furthermore, the copper ion adsorption process specifically involves: pumping wastewater containing low concentrations of copper into a resin exchange tower, controlling the pH of the influent to 4-6, and using ion exchange resin to adsorb copper to obtain high-nickel wastewater.

[0042] Furthermore, the ion exchange resin is a chelating resin, and the chelating resin is selected from one or more of the following ion exchange resins: IRC-86, XFS 43084, XFS 4195, and IRC-748.

[0043] Furthermore, the nickel extraction process also includes the treatment of various intermediate products and their recycling within the factory: in step (1), the adsorbed antimony and bismuth fine particles are washed with hydrochloric acid and sent to the antimony and bismuth extraction system to recover antimony and bismuth; in step (2), the recovered acid is used to supplement acid for other acid-requiring production systems in the factory; in step (3), the settled copper and arsenic slag is sent to the copper and arsenic treatment system to recover copper and produce arsenic products; in step (4), the ion exchange resin adsorption column after copper adsorption is sent to the electrolysis system to recover copper; and the wastewater after nickel extraction is sent to the sulfidation system for unified recycling and treatment.

[0044] Example 1

[0045] A method for separating and extracting nickel from high-concentration copper-arsenic wastewater includes the following steps:

[0046] (1) Trace metal ion retention: High-concentration copper and arsenic wastewater is pumped into membrane separation device 1, and the feed pressure is controlled at atmospheric pressure and the feed temperature is 25°C. The acidic high copper and arsenic wastewater continuously passes through the nanofiltration membrane for 4 hours. Trace antimony, bismuth and lead ions are retained on the surface of the nanofiltration membrane, while nickel-containing liquid passes through the membrane to obtain antimony and bismuth-removed wastewater. After the operation continues for a period of time, the membrane enriched with metal ions is disassembled and soaked.

[0047] (2) Acid removal: The antimony and bismuth removal wastewater obtained in step one is pumped into membrane separation device 2 to remove most of the acid contained in the liquid. The ratio of wastewater to clean water in the liquid is controlled at 1:1, the inlet pressure is atmospheric pressure, and the inlet temperature is 25℃. The antimony and bismuth removal wastewater passes through membrane material 2, and the high concentration of sulfate ions and hydrogen ions are separated to obtain deacidification residue.

[0048] (3) Co-precipitation of copper and arsenic: The deacidification residue enters the neutralization tank 1, and 32% sodium hydroxide is added to adjust the pH to 2. All arsenic ions and most copper ions precipitate into the slag in the form of copper arsenate-copper hydroxide. After pressure filtration, the filtrate is pumped into the neutralization tank 2, and 32% sodium hydroxide is added to adjust the pH to 4. The remaining copper ions are further precipitated into the slag in the form of copper hydroxide. After pressure filtration, the filter residue is returned to the neutralization tank 1 for redissolution, while the waste liquid after precipitation enters the copper ion adsorption device.

[0049] (4) Residual copper adsorption: The wastewater containing low concentration of copper after sedimentation is pumped into the IRC-86 resin exchange tower, the pH of the influent is controlled at 5.7, the adsorption time is 3h, and high nickel wastewater is obtained after copper is adsorbed by ion exchange resin.

[0050] (5) Nickel extraction: High-nickel wastewater is pumped into a nickel precipitation tank, and sodium hydroxide is added to adjust the pH of the wastewater to 8.5. Nickel ions precipitate into nickel hydroxide, which is then filtered and dried to obtain a nickel hydroxide product with a purity of 99.3%.

[0051] Example 2

[0052] A method for separating and extracting nickel from high-concentration copper-arsenic wastewater includes the following steps:

[0053] (1) Trace metal ion retention: High-concentration copper and arsenic wastewater is pumped into membrane separation device 1, and the feed pressure is controlled at atmospheric pressure and the feed temperature is 35°C. The acidic high copper and arsenic wastewater continuously passes through the nanofiltration membrane for 4 hours. Trace antimony, bismuth and lead ions are retained on the surface of the nanofiltration membrane, while nickel-containing liquid passes through the membrane to obtain antimony and bismuth-removed wastewater. After the operation continues for a period of time, the membrane enriched with metal ions is disassembled and soaked.

[0054] (2) Acid removal: The antimony-bismuth removal wastewater obtained in step one is pumped into membrane separation device 2 to remove most of the acid contained in the liquid. The ratio of wastewater to clean water in the liquid is controlled at 1:1.5, the inlet pressure is atmospheric pressure, and the inlet temperature is 25℃. The antimony-bismuth removal wastewater passes through membrane material 2, and the high concentration of sulfate ions and hydrogen ions are separated to obtain deacidification residue.

[0055] (3) Co-precipitation of copper and arsenic: The deacidification residue enters the neutralization tank 1, and 32% sodium hydroxide is added to adjust the pH to 1.6. All arsenic ions and most copper ions precipitate into the slag in the form of copper arsenate-copper hydroxide. After pressure filtration, the filtrate is pumped into the neutralization tank 2, and 32% sodium hydroxide is added to adjust the pH to 4.5. The remaining copper ions further precipitate into the slag in the form of copper hydroxide. After pressure filtration, the filter residue is returned to the neutralization tank 1 for redissolution, while the precipitated liquid enters the copper ion adsorption device.

[0056] (4) Residual copper adsorption: The liquid containing low concentration of copper after sedimentation is pumped into the XFS4195 resin exchange tower, the pH of the influent is controlled at 6.0, the adsorption time is 2.5h, and high nickel wastewater is obtained after copper is adsorbed by ion exchange resin.

[0057] (5) Nickel extraction: High-nickel wastewater is pumped into a nickel precipitation tank, and sodium hydroxide is added to adjust the pH of the wastewater to 8.2. Nickel ions precipitate into nickel hydroxide, which is then filtered and dried to obtain a nickel hydroxide product with a purity of 99.5%.

[0058] The foregoing has provided a detailed description of a method for separating and extracting nickel from high-concentration copper-arsenic wastewater according to embodiments of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and its core ideas; furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

[0059] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0060] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0061] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0062] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. A method for separating and extracting nickel from high-concentration copper-arsenic wastewater, characterized in that, The method specifically includes the following steps: S1) Trace metal ion retention: The acidic high copper and arsenic wastewater to be treated is pumped into the first membrane separation unit. The feed pressure is controlled at atmospheric pressure and the feed temperature is 25-35℃. The first membrane separation treatment is carried out using a nanofiltration membrane to retain trace metal ions of antimony, bismuth, and lead, resulting in antimony- and bismuth-free wastewater. The retained antimony and bismuth fine particles are washed with hydrochloric acid and sent to the antimony and bismuth extraction system to recover antimony and bismuth. S2) Acid Removal: The antimony-bismuth-removed wastewater obtained in S1) is pumped into the second membrane separation unit. The ratio of antimony-bismuth-removed wastewater to clean water is controlled at 1:1-1:1.5, the inlet pressure is atmospheric pressure, and the inlet temperature is 25-35℃. The membrane material of the second membrane separation unit is a porous anion exchange membrane, which is one or more of polyethylene, polypropylene, methyl 6-(dimethylamino)hexanoate, and poly(2,5-dimethylphenoxy). The second membrane separation treatment yields the deacidified residual liquid. The separated and recovered acid is sent to other acid-requiring production systems in the factory for acid replenishment. S3) Copper-arsenic co-precipitation: The deacidification residue obtained in S2) is neutralized: First, it is passed into the first tank, and 32% sodium hydroxide is added to adjust the pH to 2-3. All arsenic ions and some copper ions are precipitated, and the residue is obtained by pressure filtration. The residue is then transferred to the second tank, and the pH is adjusted to 3-5. The remaining copper is precipitated, and the residue is obtained by pressure filtration. The precipitated liquid and filter residue are obtained. The filter residue is sent to the first tank for redissolution, and the copper-arsenic residue is sent to the copper-arsenic treatment system to recover copper and produce arsenic products. S4) Copper adsorption: The settled liquid obtained in S3) is pumped into the resin exchange tower, and the pH of the influent is controlled at 4-6. Chelating resin is used for adsorption treatment to obtain high-nickel waste liquid; the chelating resin is one or more of IRC-86, XFS 43084, XFS 4195, and IRC-748; the copper-rich exchange resin adsorption column that is saturated with adsorption is sent to the electrolysis system to recover copper. S5) Nickel extraction: Add 32% sodium hydroxide to the high-nickel waste liquid obtained in S4) to adjust the pH to 8-10, control the nickel precipitation temperature to 80-90℃, and the reaction time to 1-2h to precipitate nickel ions into nickel hydroxide. Filter and dry to obtain nickel hydroxide product. The wastewater after nickel extraction is sent to the sulfidation system for unified recycling and treatment. The method achieves a nickel recovery rate of no less than 85% and yields nickel hydroxide with a purity of no less than 99.00%.

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