A short process for recovering nickel salts from copper sulfate crystallization mother liquor

Abstract

The application belongs to the technical field of wastewater treatment, and specifically discloses a short-process method for recovering nickel salt from copper sulfate crystallization mother liquor, which comprises the following steps: adding a sulfidizing agent into the copper sulfate crystallization mother liquor to perform a sulfidizing reaction, obtaining sulfidized liquid, adding an alkaline neutralizing agent into the sulfidized liquid to perform neutralization, and obtaining nickel-containing neutralization residue; through the two steps of sulfidizing and neutralization, more than 95% of the nickel salt in the copper sulfate crystallization can be recovered, qualified raw materials for high-quality nickel-containing products can be provided, efficient recovery and resource utilization of nickel are realized, no new wastewater is generated, environmental pollution is reduced, safety and environmental protection are achieved, the reagents used are cheap, the operation method is simple, industrialization is easy, and important economic and social benefits are achieved; in addition, by adding the sulfidizing agent into the copper sulfate crystallization mother liquor, copper and arsenic can also be precipitated with nickel in sections, which is beneficial to the reuse of wastewater.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a short-process method for recovering nickel salts from copper sulfate crystallization mother liquor. Background Technology

[0002] Copper sulfate crystallization mother liquor is a saturated or supersaturated solution formed during the copper sulfate crystallization process. It contains copper sulfate that did not precipitate during the initial crystallization and other possible impurities. In treating copper sulfate mother liquor, concentrated copper electrolyte is typically used to obtain crude copper sulfate crystals, thereby removing some impurities such as arsenic and nickel. However, because valuable nickel is also carried away, the total amount of nickel removed increases significantly with the increase in the amount of crude copper smelting processed, resulting in substantial resource waste. To avoid this waste, nickel recovery is necessary.

[0003] The existing traditional nickel recovery process first involves diffusion dialysis to remove acid and arsenic from copper sulfate mother liquor, then neutralizing the residual liquid from the diffusion process to remove copper and arsenic, and finally deep neutralizing to extract high-copper, high-arsenic, and high-nickel slag as raw material for nickel extraction. Because nickel-containing materials contain impurities such as copper and arsenic, the main nickel grade is low, resulting in a long nickel extraction process, high alkali consumption, and complex procedures, significantly reducing the direct recovery rate and overall nickel recovery rate. Therefore, we need to propose a short-process method for recovering nickel salts from copper sulfate crystallization mother liquor to solve the above problems. This method should be able to recover more than 95% of the nickel salts from the copper sulfate crystallization mother liquor and provide qualified raw materials for high-quality nickel-containing products, achieving efficient nickel recovery and resource utilization. Summary of the Invention

[0004] The purpose of this invention is to provide a short-process method for recovering nickel salts from copper sulfate crystallization mother liquor, which can recover more than 95% of the nickel salts from the copper sulfate crystallization mother liquor and provide qualified raw materials for high-quality nickel-containing products, thereby achieving efficient recovery and resource utilization of nickel and solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A short-process method for recovering nickel salts from copper sulfate crystallization mother liquor includes the following steps:

[0007] S1. Prepare a sulfiding agent and an alkaline neutralizing agent, wherein the weight of the sulfiding agent and the alkaline neutralizing agent prepared is the same as the weight of the copper sulfate crystallization mother liquor.

[0008] S2. Gradually add sulfiding agent to copper sulfate crystallization mother liquor to carry out sulfidation reaction. After the pH value of the reaction solution reaches 1-3, filter to obtain sulfidation slag containing copper and arsenic and sulfidation liquid.

[0009] S3. The sulfide slag is sent to the smelting system for smelting and recycling.

[0010] S4, adding an alkaline neutralizing agent to the sulfurized solution to perform a neutralization reaction, so that the PH value of the neutralization reaction solution reaches 6.5-9.5, and then filtering to obtain a neutralization residue containing nickel and a post-neutralization solution.

[0011] Preferably, in step S1, the sulfurizing agent is one or more of sodium sulfide, sodium hydrosulfide and hydrogen sulfide.

[0012] Preferably, the alkaline neutralizing agent is one or more of sodium hydroxide, calcium hydroxide and potassium hydroxide.

[0013] Preferably, the acidity of the copper sulfate crystallization mother liquor is 130-150 g / L, and the copper sulfate crystallization mother liquor needs to be filtered using a filtering device before the sulfurization reaction to remove particulate matter and suspended matter in the copper sulfate crystallization mother liquor.

[0014] Preferably, in step S2, the sulfurizing agent is added in a slow manner multiple times step by step, and stirring is performed at a speed of 100-600 r / min to allow the sulfurizing agent to fully react with the copper sulfate crystallization mother liquor, and a PH detection device is used to detect the PH of the reaction solution after each addition of the sulfurizing agent.

[0015] Preferably, the copper sulfate crystallization mother liquor needs to be heated during the sulfurization reaction, and the sulfurization reaction conditions are as follows: the heating temperature is 50-100℃, the sulfurization reaction time is 0.5-5 h, and the reaction endpoint potential is 0-150 mv.

[0016] Preferably, in step S3, when the sulfurized residue is smelted, the sulfurized residue containing copper and arsenic is first pretreated by drying and crushing, then the pretreated sulfurized residue is sent into a smelting furnace for smelting, in the smelting process, oxygen is blown in to oxidize the metal sulfide into metal oxide or metal element, and sulfur is separated out at the same time, the metal oxide or metal element is further separated and purified by electrolytic refining, so that the copper ions are reduced to pure copper on the cathode, and other impurities are left in the anode mud, and for the anode mud, arsenic is converted into a soluble salt by adding a sulfuric acid reagent, and then separated and purified by precipitation and filtration.

[0017] Preferably, in step S4, the post-sulfurized solution is fully stirred before the alkaline neutralizing agent is added to make the solution uniformly mixed, the neutralizing agent is then slowly added, and the PH value change of the reaction solution is monitored, and the reaction conditions of the reaction solution are as follows: the reaction temperature is 20-50℃, the reaction time is 1-3 h, and the stirring speed is 100-600 r / min.

[0018] Preferably, the neutralized residue needs to be washed thoroughly, and then mixed with sulfuric acid at a mass ratio of 1:2 to make the valuable metals in the neutralized residue re-dissolve to form a metal salt solution, and then filtered to obtain a nickel-containing solution, which is then purified to obtain a nickel product.

[0019] Preferably, the neutralized solution needs to be sent to a wastewater treatment system for purification treatment, and the specific process of the purification treatment is as follows:

[0020] A1, adding a flocculating agent to the neutralized solution to promote the aggregation and sedimentation of suspended particles, and obtaining a treated solution;

[0021] A2, filtering the treated solution using an activated carbon filter to obtain a filtered solution;

[0022] A3, using a reverse osmosis membrane to separate dissolved salts, organic matter and microorganisms in the filtered solution;

[0023] A4, using the metabolic action of anaerobic microorganisms to degrade organic matter in the solution;

[0024] A5, using a chemical oxidizing agent or reducing agent to change the valence state of certain compounds in the solution;

[0025] A6, using electrolysis method to remove pollutants in the solution;

[0026] A7, for the solution containing volatile substances, the volume is reduced by evaporation concentration, and valuable solutes are recovered.

[0027] The method for recovering nickel salt in copper sulfate crystallization mother liquor in a short process provided by the present application has the following advantages compared with the prior art:

[0028] 1. In the present application, sulfurizing agent is added to the copper sulfate crystallization mother liquor to carry out a sulfurization reaction, and then an alkaline neutralizing agent is added to the sulfurized solution to carry out a neutralization reaction, thereby obtaining a neutralized residue containing nickel. Through the two steps of sulfurization and neutralization, more than 95% of the nickel salt in the copper sulfate crystallization can be recovered, and qualified raw materials for high-quality nickel-containing products are provided, realizing efficient recovery and resource utilization of nickel, without generating new wastewater, reducing environmental pollution, being safe and environmentally friendly, using cheap reagents, and being easy to operate and industrialize, thus having important economic and social benefits.

[0029] 2. In the present application, by adding sulfurizing agent to the copper sulfate crystallization mother liquor, copper and arsenic can also be precipitated separately from nickel, which is beneficial to the reuse of wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The flowchart of the present application is shown in the figure;

[0031] Figure 2 The neutralization and purification process flow diagram of the present application. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0033] Embodiment 1

[0034] The present application provides a short process for recovering nickel salt in copper sulfate crystallization mother liquor as shown, comprising the following steps: Figures 1-2

[0035] S1, preparing sulfidation agent and alkaline neutralizing agent, the weight of the prepared sulfidation agent and alkaline neutralizing agent is the same as the weight of the copper sulfate crystallization mother liquor;

[0036] The sulfidation agent is one or more of sodium sulfide, sodium hydrosulfide and hydrogen sulfide, and the alkaline neutralizing agent is one or more of sodium hydroxide, calcium hydroxide and potassium hydroxide.

[0037] The acidity of the copper sulfate crystallization mother liquor is 130-150g / L, and the copper sulfate crystallization mother liquor needs to be filtered using a filtering device before the sulfidation reaction to remove particulate matter and suspended matter in the copper sulfate crystallization mother liquor.

[0038] S2, gradually adding sulfidation agent to the copper sulfate crystallization mother liquor for sulfidation reaction, so that the PH value of the reaction solution reaches 1-3, and then filtering to obtain sulfidation residue containing copper and arsenic and sulfidation solution after sulfidation;

[0039] The sulfidation agent is added in a slow manner for multiple gradual additions, and needs to be stirred at a rate of 100-600r / min to make the sulfidation agent fully react with the copper sulfate crystallization mother liquor, and PH detection device is used to detect the PH of the reaction solution after each addition of the sulfidation agent.

[0040] The reaction solution needs to be heated when the copper sulfate crystallization mother liquor is subjected to the sulfidation reaction, and the sulfidation reaction conditions are as follows: the heating temperature is 50-100℃, the sulfidation reaction time is 0.5-5h, and the reaction end potential is 0-150mv.

[0041] S3, sending the sulfidation residue to a smelting system for smelting and recycling;

[0042] ​The sulfurized residue is smelted by first drying and crushing the sulfurized residue containing copper and arsenic, then sending the pretreated sulfurized residue into a smelting furnace for smelting, in the smelting process, the metal sulfide is oxidized into metal oxide or metal element by blowing oxygen, and sulfur is separated out, the metal oxide or metal element is further separated and purified by electrolytic refining, so that the copper ions are reduced to pure copper on the cathode, and other impurities are left in the anode mud, and the anode mud is treated by adding sulfuric acid reagent to convert arsenic into soluble salt, and then separated and purified by precipitation and filtration.

[0043] S4, after the neutralization reaction, the PH value of the neutralization reaction liquid is 6.5-9.5, and the neutralization residue containing nickel and the neutralized liquid are obtained by filtration.

[0044] The sulfurized liquid is fully stirred before the alkaline neutralizer is added, so that the solution is uniformly mixed, then the neutralizer is slowly added, and the PH value change of the reaction solution is monitored, the reaction conditions of the reaction solution are: reaction temperature 20-50℃, reaction time 1-3h, and stirring speed 100-600r / min.

[0045] The neutralization residue needs to be washed thoroughly, then the neutralization residue is mixed with sulfuric acid at a mass ratio of 1:2, so that the valuable metals in the neutralization residue are re-dissolved to form a metal salt solution, then the solution containing nickel is obtained by filtration, and then the solution containing nickel is purified to obtain a nickel product.

[0046] The neutralized liquid needs to be sent to a wastewater treatment system for purification treatment, and the specific process of the purification treatment is as follows:

[0047] A1, a flocculating agent is added to the neutralized liquid to promote the aggregation and sedimentation of suspended particles, and a treated liquid is obtained, so as to remove suspended solids and part of heavy metals in the wastewater;

[0048] A2, an activated carbon filter is used to filter the treated liquid to obtain a filtered liquid, so as to remove smaller suspended particles and part of dissolved substances;

[0049] A3, a reverse osmosis membrane is used to separate dissolved salts, organic matter and microorganisms in the filtered liquid, so as to obtain water with high purity;

[0050] A4, anaerobic microorganisms are used to degrade organic matter in the solution, including activated sludge method, biofilm reactor and biological filter;

[0051] A5, chemical oxidants (such as chlorine, ozone and hydrogen peroxide) or reducing agents (such as sodium sulfite and ferrous sulfate) are used to change the valence of some compounds in the solution, so that they are more easily removed;

[0052] A6. Using electrolytic methods to remove contaminants from the solution;

[0053] A7. For solutions containing volatile substances, reducing the volume by evaporation concentration, while recovering valuable solutes.

[0054] Example 2

[0055] According to the method provided in Example 1, the first verification of actual nickel salt recovery of copper sulfate crystallization mother liquor was carried out to confirm the actual recovery rate of nickel salt, and the verification steps were as follows:

[0056] 1. Detect the composition of copper (Cu), arsenic (As) and nickel (Ni) in the copper sulfate crystallization mother liquor, and the detection results are as follows:

[0057] Element class Cu As Ni Content (g / L) 47.55 27.38 19.46

[0058] 2. Add sodium sulfide to the copper sulfate crystallization mother liquor in a certain proportion to carry out sulfidation reaction, the reaction temperature is 50°C, the reaction time is 5h, the stirring speed is 300r / min, the reaction end point potential is 150mv, after filtration and washing, the sulfidation residue containing copper and arsenic and the sulfidation liquid after sulfidation are obtained, and the composition of the sulfidation liquid after sulfidation is shown in the following table:

[0059] Element class Cu As Ni Content (g / L) 0.20 0.44 18.1

[0060] From this table, it can be concluded that the recovery rate of sulfur is 99.57%, and the sulfidation residue obtained can be used as high-quality copper-containing material into the smelting production system, and the sulfidation liquid after sulfidation enters the next process;

[0061] 3. Add sodium hydroxide to the sulfidation liquid in a certain proportion, the reaction temperature is 20°C, the reaction time is 3h, the stirring speed is 300r / min, the end point pH is 6.5, after filtration and washing, the neutralization residue and the neutralization liquid after neutralization are obtained, and the composition of the neutralization liquid after neutralization is shown in the following table:

[0062] Element class Cu As Ni Content (g / L) 0.01 0.30 0.65

[0063] From the data in this table, it can be concluded that the recovery rate of nickel in the neutralization process is 96.41%, which is greater than 95%, and the neutralization residue can be sold as high-quality nickel raw material, and the neutralization liquid after neutralization enters the wastewater treatment process.

[0064] In the whole process, since the copper and arsenic are completely precipitated in the sulfidation process, the loss rate of nickel is low, and the efficient separation of impurity elements and target elements is well achieved.

[0065] Example 3

[0066] According to the method provided in Example 1, the second verification of the actual nickel salt recovery of the copper sulfate crystallization mother liquor was carried out to confirm the actual recovery rate of the nickel salt, and the verification steps were as follows:

[0067] 1. The components of copper (Cu), arsenic (As) and nickel (Ni) in the copper sulfate crystallization mother liquor were detected, and the detection results were as shown below:

[0068] Element class Cu As Ni Content (g / L) 49.42 25.17 16.89

[0069] 2. A certain proportion of sodium hydrosulfide was added to the copper sulfate crystallization mother liquor for sulfidation reaction, the reaction temperature was 70°C, the reaction time was 3h, the stirring speed was 400r / min, and the reaction end point potential was 100mv. After filtration and washing, the copper and arsenic containing sulfidation residue and the sulfidation liquid after sulfidation were obtained, and the components of the sulfidation liquid after sulfidation were detected as shown in the table below:

[0070] Element class Cu As Ni Content (g / L) 0.22 0.34 14.92

[0071] From the table, it can be seen that the recovery rate of sulfur is 99.55%, and the obtained sulfidation residue can be used as high-quality copper-containing material into the smelting production system, and the sulfidation liquid after sulfidation enters the next process;

[0072] 3. A certain proportion of calcium hydroxide was added to the sulfidation liquid, the reaction temperature was 30°C, the reaction time was 2h, the stirring speed was 400r / min, and the end point pH was 8.0. After filtration and washing, the neutralization residue and the neutralization liquid after neutralization were obtained, and the components of the neutralization liquid after neutralization were detected as shown in the table below:

[0073] Element class Cu As Ni Content (g / L) 0.02 0.18 0.37

[0074] From the table data, it can be seen that the recovery rate of nickel in the neutralization process is 97.55%, which is greater than 95%, and the neutralization residue can be sold as high-quality nickel raw material, and the neutralization liquid after neutralization enters the wastewater treatment process.

[0075] In the whole process, since the copper and arsenic are completely precipitated in the sulfidation process, the loss rate of nickel is low, and the efficient separation of impurity elements and target elements is well achieved.

[0076] Example 4

[0077] According to the method provided in Example 1, the third verification of the actual nickel salt recovery of the copper sulfate crystallization mother liquor was carried out to confirm the actual recovery rate of the nickel salt, and the verification steps were as follows:

[0078] 1. The components of copper (Cu), arsenic (As) and nickel (Ni) in the copper sulfate crystallization mother liquor were detected, and the detection results were as shown below:

[0079] Element class Cu As Ni Content (g / L) 43.29 26.09 17.88

[0080] 2. Add hydrogen sulfide to the copper sulfate crystallization mother liquor in a certain proportion to carry out sulfidation reaction, the reaction temperature is 100℃, the reaction time is 1h, the stirring speed is 200r / min, the reaction end point potential is 50mv, after filtration and washing, the sulfidation residue containing copper and arsenic and the sulfidation liquid after sulfidation are obtained, the composition of the sulfidation liquid after sulfidation is shown in the following table:

[0081] Element class Cu As Ni Content (g / L) 0.17 0.39 15.97

[0082] From the table, it can be concluded that the recovery rate of sulfur is 99.6%, the sulfidation residue obtained can be used as high-quality copper-containing material into the smelting production system, and the sulfidation liquid after sulfidation enters the next process;

[0083] 3. Add potassium hydroxide to the sulfidation liquid in a certain proportion, the reaction temperature is 50℃, the reaction time is 1h, the stirring speed is 200r / min, the end point pH is 9.5, after filtration and washing, the neutralization residue and the neutralization liquid after neutralization are obtained, the composition of the neutralization liquid after neutralization is shown in the following table:

[0084] Element class Cu As Ni Content (g / L) 0.01 0.25 0.47

[0085] From the table data, it can be concluded that the recovery rate of nickel in the neutralization process is 97.06%, which is greater than 95%, the neutralization residue can be sold as high-quality nickel raw material, and the neutralization liquid after neutralization enters the wastewater treatment process.

[0086] In the whole process, since the copper and arsenic are completely precipitated in the sulfidation process, the loss rate of nickel is low, and the efficient separation of impurity elements and target elements is well achieved.

[0087] In summary, by adding a sulfidation agent to the copper sulfate crystallization mother liquor to carry out sulfidation reaction, obtaining the sulfidation liquid after sulfidation, and then adding an alkaline neutralization agent to the sulfidation liquid after sulfidation to carry out neutralization, obtaining the neutralization residue containing nickel, more than 95% of the nickel salt in the copper sulfate crystallization can be recovered through the two steps of sulfidation and neutralization, and qualified raw materials for high-quality nickel-containing products are provided, realizing efficient recovery and resource utilization of nickel, without generating new wastewater, reducing environmental pollution, being safe and environmentally friendly, the reagents used are cheap, the operation method is simple, and the method is easy to industrialize, having important economic and social benefits, in addition, by adding a sulfidation agent to the copper sulfate crystallization mother liquor, copper and arsenic can be precipitated with nickel in stages, which is beneficial to the reuse of wastewater.

[0088] Finally, it should be noted that the above description is only a preferred embodiment of the present application and is not intended to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or make equivalent replacements for some technical features, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A short process for recovering nickel salts from a copper sulfate crystallization mother liquor, characterized in that: It comprises the following steps: S1, preparing a sulfidation agent and an alkaline neutralizing agent, the weight of the sulfidation agent and the alkaline neutralizing agent prepared is the same as the weight of the copper sulfate crystallization mother liquor; S2, gradually adding the sulfidation agent in the copper sulfate crystallization mother liquor to carry out a sulfidation reaction, so that the pH value of the reaction solution reaches 1-3, and then filtering to obtain a sulfidation residue containing copper and arsenic and a post-sulfidation solution; S3, sending the sulfidation residue into a smelting system for smelting and recycling; S4, adding an alkaline neutralizing agent to the post-sulfidation solution to carry out a neutralization reaction, so that the pH value of the neutralization reaction solution reaches 6.5-9.5, and then filtering to obtain a neutralization residue containing nickel and a post-neutralization solution; The post-sulfidation solution is fully stirred before the alkaline neutralizing agent is added, so that the solution is uniformly mixed, then the neutralizing agent is slowly added, and the pH value change of the reaction solution is monitored at the same time, the reaction conditions of the reaction solution are: the reaction temperature is 20-50℃, the reaction time is 1-3h, and the stirring speed is 100-600r / min; The neutralization residue needs to be washed thoroughly, then the neutralization residue is mixed with sulfuric acid at a mass ratio of 1:2, so that the valuable metals in the neutralization residue are redissolved to form a metal salt solution, then filtering to obtain a solution containing nickel, and then purifying the solution containing nickel to obtain a nickel product.

2. The process for short flow recovery of nickel salts from copper sulfate crystallization mother liquor as claimed in claim 1 wherein: In step S1, the sulfidation agent is one or more of sodium sulfide, sodium hydrosulfide and hydrogen sulfide.

3. A process for short flow recovery of nickel salts from copper sulfate crystallization mother liquor as claimed in claim 2, wherein: The alkaline neutralizing agent is one or more of sodium hydroxide, calcium hydroxide and potassium hydroxide.

4. The process for short flow recovery of nickel salts from copper sulfate crystallization mother liquor as claimed in claim 3 wherein: The acidity of the copper sulfate crystallization mother liquor is 130-150g / L, and the copper sulfate crystallization mother liquor needs to be filtered using a filtering device before the sulfidation reaction to remove particulate matter and suspended matter in the copper sulfate crystallization mother liquor.

5. A process for short flow recovery of nickel salts from copper sulfate crystallization mother liquor as claimed in claim 4, wherein: In step S2, the sulfidation agent is added in a slow manner for multiple times, and needs to be stirred at a speed of 100-600r / min to fully react with the copper sulfate crystallization mother liquor, and a pH detection device is used to detect the pH value of the reaction solution after each addition of the sulfidation agent.

6. A process for short flow recovery of nickel salts from copper sulfate crystallization mother liquor as claimed in claim 5 wherein: The reaction solution needs to be heated when the copper sulfate crystallization mother liquor is subjected to the sulfidation reaction, and the sulfidation reaction conditions are: the heating temperature is 50-100℃, the sulfidation reaction time is 0.5-5h, and the reaction endpoint potential is 0-150mv.

7. A process for short flow recovery of nickel salts from copper sulfate crystallization mother liquor as claimed in claim 6 wherein: In step S3, when the sulfidation residue is smelted, the sulfidation residue containing copper and arsenic is first pretreated by drying and crushing, then the pretreated sulfidation residue is sent into a smelting furnace for smelting, in the smelting process, oxygen is blown in to oxidize metal sulfides into metal oxides or metal elements, and sulfur is separated out at the same time, the metal oxides or metal elements are further separated and purified by electrolytic refining, so that copper ions are reduced to pure copper on the cathode, and other impurities are left in the anode mud, and for the anode mud, arsenic is converted into soluble salts by adding sulfuric acid reagent, and then separated and purified by precipitation and filtration.

8. A process for short flow recovery of nickel salts from copper sulfate crystallization mother liquor as claimed in claim 7, wherein: The post-neutralization solution needs to be sent into a wastewater treatment system for purification treatment, and the specific process of the purification treatment is as follows: A1, adding a flocculating agent to the post-neutralization solution to promote the aggregation and sedimentation of suspended particles to obtain a treatment solution; A2, filtering the treatment liquid using an activated carbon filter to obtain a filtered liquid; A3, separating dissolved salts, organic matter and microorganisms from the filtered liquid using a reverse osmosis membrane; A4, degrading organic matter in the solution using the metabolic action of anaerobic microorganisms; A5, changing the valence of certain compounds in the solution using chemical oxidizing or reducing agents; A6, removing pollutants from the solution using electrolytic methods; A7, for solutions containing volatile substances, reducing the volume by evaporation concentration, while recovering valuable solutes.

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