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

Abstract

The invention discloses a method for separating and extracting nickel from high-concentration copper-arsenic wastewater, which comprises the following steps: firstly, carrying out first membrane separation treatment on acidic high-copper-arsenic wastewater to obtain antimony-bismuth-removed wastewater; carrying out secondary membrane separation treatment on the antimony and bismuth removed wastewater to obtain deacidified residual liquid; carrying out neutralization treatment on the deacidified residual liquid to obtain a settled liquid; carrying out adsorption treatment on the settled liquid by adopting ion exchange resin to obtain high-nickel waste liquid; sodium hydroxide is added into the high-nickel waste liquid, nickel ions are settled into nickel hydroxide, filtering and drying are conducted, and a nickel hydroxide product is obtained. According to the method, nickel is extracted from the high-copper-arsenic wastewater in a mode of combining a membrane separation method and a chemical precipitation method, the technological process is simple, efficient separation of copper-arsenic ions and nickel ions can be effectively achieved, and the purity of recycled nickel hydroxide is not lower than 99%; the recovery rate of nickel is not lower than 85%, no excessive chemical substance is input, meanwhile, arsenic-containing dangerous waste is not generated, loss of copper and nickel elements can be reduced to the maximum extent, and meanwhile the environment is not polluted.

Description

Technical Field

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

[0002] The components in copper smelting wastewater are complex, containing not only high concentrations of arsenic, copper, and nickel ions, but also certain concentrations of antimony, bismuth, and other ions. Among them, the concentrations of copper and arsenic ions account for up to 40 - 70 g / L, while the concentrations of antimony, bismuth, and other ions are relatively low, making separation difficult. The direct discharge of heavy metal ion wastewater not only greatly affects the environment but also causes the loss of valuable metals.

[0003] Currently, steel mills, chemical plants, dye factories, electroplating factories, and smelting factories, etc. 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 effects of different metal ions at different pH values and adopts the method of stepwise adjusting pH to separate iron, chromium, and fluoride ions and recover metallic nickel, but this method does not mention the recovery rate of nickel; Chinese invention patent CN 106544528 discloses a method for recovering metallic nickel from pickling wastewater. Although this method can recover nickel from wastewater, the entire process flow is long, a large amount of chemical materials are input, and the purity of the produced nickel is not described.

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

[0005] Aiming at the difficulties of the prior art, the present invention aims to provide a method for extracting metallic nickel from high-copper-arsenic wastewater with less chemical substances input, good process separation effect, and high recovery rate.

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

[0007] S1) Interception of trace metal ions: The acidic high-copper-arsenic wastewater to be treated is subjected to the first membrane separation treatment to obtain antimony- and bismuth-removed wastewater;

[0008] S2) Acid removal: The antimony- and bismuth-removed wastewater obtained in S1) is subjected to the second membrane separation treatment to obtain acid-removed residual liquid;

[0009] S3) Copper-arsenic co-precipitation: The acid-removed residual liquid obtained in S3) is subjected to neutralization treatment, and after filtration, the settled liquid is obtained;

[0010] S4) Residual copper adsorption: The settled liquid obtained in S3) is treated by adsorption with ion exchange resin to obtain high-nickel waste liquid;

[0011] S5) Nickel extraction: A certain amount of sodium hydroxide is added to the high-nickel waste liquid obtained in S4), and nickel ions are precipitated as nickel hydroxide, which is then filtered and dried to obtain nickel hydroxide products.

[0012] The method of the present invention must be strictly implemented according to the above procedures, and the process sequence cannot be arbitrarily adjusted.

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

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

[0015] Furthermore, the specific process of S2) is: pumping the antimony- and bismuth-removed wastewater into the second membrane separation device, controlling the feed ratio of the antimony- and bismuth-removed wastewater to clear water at 1:1 - 1:1.5, the feed pressure at atmospheric pressure, and the feed temperature at 25 - 35°C;

[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: First, the deacidified residue liquid is introduced into the first tank, and sodium hydroxide with a concentration of 32% is added to adjust the pH to 2 - 3, so that all arsenic ions and part of the copper ions are precipitated, and then pressure filtration is carried out to obtain a filtrate;

[0018] The obtained filtrate is introduced into the second tank, and then the pH is adjusted to 3 - 5 to precipitate the remaining copper, and then pressure filtration is carried out to obtain the settled liquid and filter residue, and the filter residue is sent back to the first tank for redissolution.

[0019] Furthermore, the specific process of S4) is: pumping the settled liquid into the resin exchange tower, controlling the feed pH at 4 - 6, and adsorbing copper with 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 ion exchange resin IRC-86, XFS43084, XFS 4195, and IRC-748.

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

[0022] Add sodium hydroxide with a concentration of 32% to the high-nickel waste liquid to adjust the pH to 8-10, control the nickel precipitation temperature at 80-90 °C, and the reaction time at 1-2 h.

[0023] Furthermore, the nickel recovery rate of the method is not less than 85%, and the purity of the obtained nickel hydroxide is not less than 99.00%.

[0024] A kind of nickel hydroxide is prepared by the above method.

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

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

[0027] (2) The front end uses a membrane separation method to pre-separate low-concentration impurity ions such as antimony and bismuth, and then uses a fractional precipitation method to remove copper and arsenic ions. The purity of the produced nickel hydroxide slag is as high as 99%, and the separation effect is good;

[0028] (3) The whole process has simple process operation, without too much chemical material input, and there is no need for subsequent purification treatment of nickel slag, saving labor costs. The high-concentration acid is pre-separated, effectively reducing the usage amount of sodium hydroxide during subsequent chemical precipitation and saving costs. Description of the Drawings

[0029] Figure 1 It is a process flow block diagram of a method for separating and extracting nickel from high-concentration copper and arsenic wastewater according to the present invention. Detailed Embodiments

[0030] The technical solutions of the present invention will be further described below in conjunction with specific implementation cases.

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

[0032] (1) Trace metal ion interception: Pump the high-concentration copper and arsenic wastewater into the membrane separation device 1, control the feed pressure at atmospheric pressure, the feed temperature at 25-35 °C, the acidic high-copper and arsenic wastewater passes through the membrane material 1, and trace antimony, bismuth, and lead ions are intercepted to obtain de-antimony and bismuth wastewater;

[0033] (2) Acid removal: Pump the acid-containing wastewater into the membrane separation device 2, control the liquid inlet ratio of wastewater to fresh water at 1:1-1:1.5, the inlet pressure at atmospheric pressure, the inlet temperature at 25-35 °C, the de-antimony and bismuth wastewater passes through the membrane material 2, and relatively high-concentration sulfate ions and hydrogen ions are separated to obtain de-acid residue liquid;

[0034] (3) Copper-arsenic coprecipitation: The deacidified residual liquid enters the neutralization tank, sodium hydroxide is added to adjust the pH, copper and arsenic ions are precipitated, and then filtered to obtain the post-sedimentation liquid;

[0035] (4) Residual copper adsorption: Ion exchange resin is used to adsorb low-concentration copper to obtain high-nickel waste liquid;

[0036] (5) Nickel extraction: Sodium hydroxide is continuously added to adjust the pH of the wastewater to 8-9, nickel ions are precipitated as nickel hydroxide, and then filtered and dried to obtain nickel hydroxide products;

[0037] Further, the high-concentration copper-arsenic wastewater is the mother liquor after recrystallizing copper sulfate during copper smelting, which contains high concentrations of acid, high arsenic, high copper ions, some nickel ions, and trace amounts of antimony, bismuth, lead and other ions;

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

[0039] Further, 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] Further, the copper-arsenic coprecipitation process is carried out in two steps: First, the 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, and then pressure-filtered. The filtrate enters tank 2, and after adjusting the pH to 3-5, the remaining copper is precipitated, and then pressure-filtered. The filter residue is sent to tank 1 for redissolution, and the high-nickel waste liquid enters step (4) for residual copper adsorption;

[0041] Further, the specific process of copper ion adsorption is as follows: The wastewater containing low-concentration copper is pumped into the resin exchange tower, the inlet liquid pH is controlled to be 4-6, and after copper is adsorbed by ion exchange resin, high-nickel wastewater is obtained;

[0042] Further, the ion exchange resin is a chelating resin, and the chelating resin is selected from one or more of ion exchange resin IRC-86, XFS 43084, XFS 4195, and IRC-748;

[0043] Further, the treatment of each intermediate product and the internal recycling in the factory are also included during the process of nickel extraction: In step (1), the adsorbed antimony and bismuth fine particles are treated by hydrochloric acid pickling and sent to the antimony and bismuth extraction system to recover antimony and bismuth. The recovered acid in step (2) is used for acid supplementation in other acid-required production systems in the factory. The copper-arsenic slag after sedimentation in step (3) is sent to the copper-arsenic treatment system to recover copper and produce arsenic products. The ion exchange resin adsorption column after copper adsorption in step (4) is sent to the electrolysis system to recover copper. The wastewater after nickel extraction is sent to the sulfide system for unified recovery and treatment.

[0044] Example 1

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

[0046] (1) Trace metal ion interception: high-concentration copper-arsenic wastewater is pumped into the membrane separation device 1, the feed pressure is controlled to be normal pressure, the feed temperature is controlled to be 25°C, and the acidic high-copper-arsenic wastewater continues to pass through the nanofiltration membrane for 4 hours. Trace antimony, bismuth, and lead ions are intercepted on the surface of the nanofiltration membrane, while the nickel-containing liquid passes through the membrane to obtain antimony- and bismuth-free wastewater. After the operation continues for a period of time, the membrane enriched with metal ions is disassembled for soaking and washing;

[0047] (2) Acid removal: The antimony-free bismuth wastewater obtained in step 1 is pumped into a membrane separation device 2 to remove most of the acid contained in the liquid, and the ratio of wastewater to clean water is controlled to be 1:1, the liquid inlet pressure is normal pressure, and the liquid inlet temperature is 25° C. The antimony-free bismuth wastewater passes through the membrane material 2, and the high concentration of sulfate ions and hydrogen ions are separated to obtain a deacidified residual liquid;

[0048] (3) Copper-arsenic co-precipitation: the deacidified residual liquid enters the neutralization tank 1, 32% sodium hydroxide is added to adjust the pH to 2, all arsenic ions and most of the copper ions are precipitated into the slag in the form of copper arsenate, the filtrate is filtered, and the filtrate is pumped into the neutralization tank 2, 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, the filtrate is filtered, and the filter residue is returned to the neutralization tank 1 to be redissolved, and the waste liquid after precipitation enters the copper ion adsorption device;

[0049] (4) Residual copper adsorption: The wastewater containing low-concentration copper after precipitation is pumped into the IRC-86 resin exchange tower, the inlet pH is controlled to 5.7, the adsorption time is 3 hours, and the copper is adsorbed by ion exchange resin to obtain high-nickel wastewater;

[0050] (5) Nickel extraction: High-nickel wastewater is pumped into a nickel precipitation tank, and sodium hydroxide is continuously added to adjust the pH of the wastewater to 8.5. Nickel ions are precipitated as nickel hydroxide, which is 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 comprises the following steps:

[0053] (1) Trace metal ion interception: high-concentration copper-arsenic wastewater is pumped into the membrane separation device 1, the feed pressure is controlled to be normal pressure, the feed temperature is controlled to be 35°C, and the acidic high-copper-arsenic wastewater continues to pass through the nanofiltration membrane for 4 hours. Trace antimony, bismuth, and lead ions are intercepted on the surface of the nanofiltration membrane, while the nickel-containing liquid passes through the membrane to obtain antimony- and bismuth-free wastewater. After the operation continues for a period of time, the membrane enriched with metal ions is disassembled for soaking and washing;

[0054] (2) Acid removal: Pump the antimony- and bismuth-removed wastewater obtained in Step 1 into the membrane separation device 2 to remove most of the acid contained in the liquid. Control the feed ratio of wastewater to fresh water at 1:1.5, the feed pressure at atmospheric pressure, and the feed temperature at 25°C. The antimony- and bismuth-removed wastewater passes through the membrane material 2, and sulfate ions and hydrogen ions with relatively high concentrations are separated to obtain acid-removed residual liquid;

[0055] (3) Copper-arsenic coprecipitation: The acid-removed residual liquid 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 in the form of copper hydrogen arsenate into the slag. After pressure filtration, the filtrate is pumped into the neutralization tank 2, and then 32% sodium hydroxide is added to adjust the pH to 4.5. The remaining copper ions further precipitate in the form of copper hydroxide into the slag. After pressure filtration, the filter residue is returned to the neutralization tank 1 for re-dissolution, and the settled liquid enters the copper ion adsorption device;

[0056] (4) Residual copper adsorption: Pump the settled liquid containing low-concentration copper into the XFS4195 resin exchange tower, control the feed pH at 6.0, and the adsorption time at 2.5 h. After adsorbing copper using ion exchange resin, high-nickel wastewater is obtained;

[0057] (5) Nickel extraction: Pump the high-nickel wastewater into the nickel precipitation tank, and continue to add sodium hydroxide to adjust the pH of the wastewater to 8.2. Nickel ions precipitate as nickel hydroxide, which is filtered and dried to obtain nickel hydroxide products with a purity of 99.5%.

[0058] The above has introduced in detail a method for separating and extracting nickel from high-concentration copper-arsenic wastewater provided by an embodiment of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

[0059] As certain terms 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 terms to refer to the same component. The specification and claims do not use the difference in names as a way to distinguish components, but use the difference in functions of components as the criterion for distinction. As mentioned throughout the specification and claims, "comprising" and "including" are open-ended terms, so they should be interpreted as "including / including but not limited to". "Substantially" means within an acceptable error range. Those skilled in the art can solve the technical problems within a certain error range and basically achieve the technical effects. The subsequent description in the specification is the preferred implementation manner for implementing the present application, but the description is for the purpose of explaining the general principles of the present application and is not used to limit the scope of the present application. The protection scope of the present application shall be determined by the scope defined by the appended claims.

[0060] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a commodity or system comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such commodity or system. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the commodity or system comprising said element.

[0061] It should be understood that the term "and / or" used herein is merely a description of the associated relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B may represent: the sole existence of A, the simultaneous existence of A and B, and the sole existence of B. Additionally, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0062] The foregoing description illustrates and describes several preferred embodiments of the present application. However, as previously mentioned, it should be understood that the present application is not limited to the forms disclosed herein, should not be regarded as excluding other embodiments, but 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 above teachings or the technology or knowledge in the relevant field. Any alterations and changes made by those skilled in the art that do not depart from the spirit and scope of the present application shall fall within the protection scope of the appended claims of the present application.

Claims

1. A method for separating and extracting nickel from high-concentration copper-arsenic wastewater, characterized in that: The method specifically comprises the following steps: S1) Trace metal ion interception: the acidic high-copper-arsenic wastewater to be treated is subjected to a first membrane separation treatment to obtain antimony- and bismuth-removed wastewater; S2) acid removal: subjecting the antimony- and bismuth-removed wastewater obtained in S1) to a second membrane separation treatment to obtain a deacidified residual liquid; S3) copper-arsenic co-precipitation: neutralizing the deacidified residual liquid obtained in S2), filtering and obtaining a precipitated liquid; S4) adsorption of residual copper: the sedimentation liquid obtained in S3) is treated by adsorption with ion exchange resin to obtain high-nickel waste liquid; S5) nickel extraction: adding sodium hydroxide to the high-nickel waste liquid obtained in S4) to precipitate nickel ions into nickel hydroxide, which is filtered and dried to obtain a nickel hydroxide product.

2. The method according to claim 1, characterized in that: The high-concentration copper-arsenic wastewater in S1) is the mother liquor after recrystallization of copper sulfate in the copper smelting process.

3. The method according to claim 1, characterized in that The specific process of S1) is: pumping the acidic high-copper and arsenic wastewater into the first membrane separation device, controlling the feed pressure to be normal pressure and the feed temperature to be 25-35° C.; the first membrane material is a nanofiltration membrane.

4. The method according to claim 1, characterized in that: The specific process of S2) is: the second membrane separation device of the de-antimony bismuth wastewater is used to control the inlet ratio of the de-antimony bismuth wastewater and the clean water to be 1:1-1:1.5, the inlet pressure is normal pressure, and the inlet temperature is 25-35°C; The second membrane material is a porous anion exchange membrane; the porous anion exchange membrane is one or more of polyethylene, polypropylene, 6-(dimethylamino) methyl hexanoate (MDMH), and poly(2,5-dimethylphenoxy).

5. The method according to claim 1, characterized in that The specific process of S3) is as follows: first, the deacidified residual liquid is passed into the first tank, 32% sodium hydroxide is added to adjust the pH to 2-3, all arsenic ions and part of copper ions are precipitated, and filter-pressed to obtain a filtrate; The obtained filtrate enters the second tank, and then the pH is adjusted to 3-5, the residual copper is precipitated, and filter-pressed to obtain the precipitated liquid and filter residue, which is then sent to the first tank for dissolution.

6. The method according to claim 1, characterized in that The specific process of S4) is: pumping the liquid after sedimentation into a resin exchange tower, controlling the pH of the inlet liquid to be 4-6, and using ion exchange resin to adsorb copper to obtain high-nickel waste liquid.

7. The method according to claim 6, characterized in that The ion exchange resin is a chelating resin, and the chelating resin is one or more of ion exchange resins IRC-86, XFS 43084, XFS 4195, and IRC-748.

8. The method according to claim 1, characterized in that The specific process of S5) is: 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° C., and the reaction time to 1-2 hours.

9. The method according to claim 1, characterized in that: The nickel recovery rate of the method is not less than 85%, and the purity of the obtained nickel hydroxide is not less than 99.00%.

10. A nickel hydroxide, characterized in that The nickel hydroxide is prepared by the method according to any one of claims 1 to 9.

Images