CN100406591C - A method for extracting metal copper from electronic waste - Google Patents

Abstract

This invention relates to a method for extracting Cu from electrical wastes. The method comprises: utilizing electrical wastes such as printed circuit board as the raw materials, dissolving Cu by oxygen via indirect oxidation in a three-phase bed, extracting Cu by solvent extraction, performing back extraction, concentrating, and performing electrodeposition on the concentrate to obtain Cu with purity up to 99.99%. The method can recover Cu from electrical wastes such as printed circuit board, thus reducing environmental pollution.

Description

A method for extracting metal copper from electronic waste

technical field

The invention belongs to the field of inorganic chemistry, in particular to a method for extracting metal copper from electronic waste.

Background technique

Electronic waste such as printed circuit boards contains dozens of elements, so many elements bring great difficulties to the comprehensive treatment of electronic waste. And it contains a lot of highly toxic elements, if not handled properly, it will bring great harm to the environment and human health. At the same time, these elements also contain many valuable metals, among which copper has the highest content. If copper is not recycled and discarded directly, it will be a great waste of resources. According to data, 130 kg of copper can be separated from 1 ton of electronic boards (mobile phones and computers). Therefore, the development of a process for extracting metals from electronic waste such as printed circuit boards can not only eliminate its harm to the environment and human beings, but also has good economic benefits.

In the existing technology, the printed circuit boards are mechanically sorted to separate non-metals and metals, and the recovery methods of copper in the metal mixture mainly include physical methods, chemical methods and microbial methods. The physical method mainly uses gravity separation, magnetic separation, electrostatic separation and other methods to separate the copper in the metal mixture. The disadvantage is that the recovery rate and grade of copper are not high; the microbial method is not mature enough and is still in the stage of exploration; In the chemical method, the circuit board is first oxidized with concentrated sulfuric acid or nitric acid, and then other metals are added to replace the copper ions, or the solution is directly heated to obtain copper sulfate crystals. These methods have low recovery rate, high corrosion or processing costs. High disadvantage.

Contents of the invention

technical problem to be solved

The technical problem to be solved by the present invention is to provide a method for extracting copper from electronic waste, so as to make up for the above-mentioned deficiencies and defects of existing technologies such as mechanical sorting, physical, chemical and microbial methods.

Technical solutions

The invention provides a method for extracting copper from electronic waste, which comprises the following steps in turn:

a) In the three-phase bed that can be fed with oxygen and oxygen carrier, the aqueous solution of electronic waste and oxygen carrier is mixed at a weight ratio of 1:1 to 20, and the pH value of the solution is adjusted to less than 1.0 with acid, and at a temperature of 60 to 60 Under the conditions of 90°C and a reaction time of 4 to 10 hours, the electronic waste is catalyzed and oxidized to complete reaction;

b) filtering the reacted mixture, extracting copper from the filtrate by solvent extraction, back-extracting with ferrous sulfate, and concentrating the back-extraction solution;

c) electrowinning the concentrated solution to extract copper by electrowinning, and retaining the solution after electrowinning;

d) regenerate the solution after electrowinning, and recycle it in step c).

One of the preferred schemes of the above method for extracting copper from electronic waste is that the oxygen carrier described in step a) is nitrogen oxide, Mn ion or Mn oxide.

The second preferred solution of the above-mentioned method for extracting copper from electronic waste is that the aqueous solution concentration of the oxygen carrier in step a) is 0.01-5 mol/L.

The third preferred solution of the above-mentioned method for extracting copper from electronic waste is that the acid for adjusting the pH value of the solution described in step a) is sulfuric acid.

The fourth preferred solution of the above-mentioned method for extracting copper from electronic waste is that there is a step of crushing electronic waste before step a).

The fifth preferred solution of the above-mentioned method for extracting copper from electronic waste is that the stripping solution described in step b) is concentrated to a concentration above 40 g/L.

The sixth preferred solution of the above method for extracting copper from electronic waste is that the extraction agent used in step b) is Li×984.

The seventh preferred solution of the above method for extracting copper from electronic waste is that the electronic waste described in step a) is a printed circuit used in home computers, televisions, mobile phones, game consoles, electronic cards, or industrial equipment plate.

The working principle of the present invention is as follows:

Electronic waste such as printed circuit boards contains many metal and non-metal elements. Since these metals are closely combined with plastics, it is difficult to achieve complete separation of metals and plastics by mechanical methods. Therefore, oxygen is used to indirect oxidation circuits under the action of oxygen carriers. The metal that is easily oxidized is oxidized to ions, and is completely separated from the metal and plastic that are difficult to oxidize. Then, the copper is extracted and separated from the pretreatment liquid with an extractant, and back-extracted to obtain a concentrated solution of copper ions.

The oxygen indirect oxidation reaction is:

3Cu+2HNO ₃ +3H ₂ SO ₄ ＝3CuSO ₄ +2NO+4H ₂ O (1)

NO ₂ +H ₂ O→HNO ₃ (3)

NO+NO ₂ +H ₂ O→2HNO ₂ (4)

3HNO ₂ →HNO ₃ +H ₂ O+2NO (5)

H ⁺ +Mn ²⁺ +O ₂ →H ₂ O+Mn ³⁺ (6)

Mn ³⁺ +Cu→Cu ²⁺ (7)

The extraction reaction is:

2RH(o)+Cu ²⁺ (a)＝R ₂ Cu(o)+2H ⁺ (8)

The stripping reaction is:

R ₂ Cu(o)+2H ⁺ (a)=2RH(o)+Cu ²⁺ (9)

The obtained concentrated solution of copper ions can be electro-deposited by an electro-deposition method to obtain high-purity electro-deposited copper. Wherein, the cathode reaction is: Cu ²⁺ +2e=Cu (10)

The reaction of the anode is: 2OH ^- ＝1/2O ₂ +H ₂ O+2e (11)

For realizing the present invention, said extraction and follow-up steps are as follows: under room temperature condition, extracting agent and filtrate are mixed, compared (O/A) is (10～1): 1, and the concentration of extracting agent is (10 % ~ 100%), adjust the pH value (1.0 ~ 3.5) with inorganic acid, stir the mixed solution with a stirrer with a set stirring speed of (100r/min ~ 1300r/min), through secondary extraction and primary reaction Extraction, the time of each stage is (1min~10min), and the copper sulfate solution (40g/L~50g/L) that meets the requirements of electrowinning can be obtained. Then put the copper sulfate solution into the electrolytic cell for electrowinning, the temperature of the cell is (20℃～60℃), and the flow rate of the electrolyte on the surface of the cathode is (0.05m ³ /(m ² ·h)～1.0m ³ /(m ² h)), adjust the current density to (190A/m ² ~340A/m ² ), and the cell voltage to (1.2v~3.2v).

Beneficial effect

On the premise that the printed circuit board is pretreated by a wet method, the present invention extracts copper from the printed circuit board pretreatment liquid with complex components by using an extraction-electrodeposition process, thereby realizing the harmlessness, reduction, and reduction of electronic waste. Recycling, the extraction-electrodeposition process adopted in the present invention can recover copper to the maximum extent.

The recovery rate and grade of copper provided by the method of the invention are high, and the copper purity is as high as 99.99 percent; the corrosion is reduced due to the catalytic oxidation reaction, the treatment conditions are not harsh, and the treatment cost is low.

Description of drawings

Fig. 1 is technological process of the present invention.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

For the experimental methods without specific conditions indicated in the following examples, the conventional conditions or the conditions suggested by the manufacturer are usually followed. Inorganic chemical reagents were purchased from Shanghai Chemical Reagent Factory, Li×984 (copper hydroxyketoxime extractant, from Henkel, Germany).

Example 1

Put the crushed printed circuit board into the three-phase bed, then add 5mol/L oxygen carrier, the weight ratio of the two is 1:10, adjust the pH value of the solution with sulfuric acid to be greater than 1.0, and use a high-pressure pump to press oxygen into the three-phase bed bed, and then the reactant was heated to 60° C., and reacted for 6 hours. When the printed circuit board was completely oxidized, the filtrate was obtained by filtration. Under room temperature conditions, the extractant and the filtrate are mixed, the ratio (O/A) is 2: 1, the concentration of the extractant is 30%, the pH value is adjusted to 2.0 with mineral acid, and the set stirring speed is 910r/ min, the stirrer stirs the mixed solution, through the secondary extraction and the primary stripping, the time of each stage is 3min, and the copper sulfate solution 40g/L that meets the electrowinning requirements can be obtained. Then put the copper sulfate solution into the electrolytic cell for electrowinning, the cell temperature is 45°C, the electrolyte flow rate on the surface of the cathode is 0.12m ³ /(m ² ·h), the current density is adjusted to 240A/m ² , and the cell voltage is 2.3 v, the purity of the obtained copper is 99.99%.

Example 2

Put the pulverized printed circuit board into the three-phase bed, stir evenly, then add 2.5mol/L of oxygen carrier, the weight ratio of the two is 1:1, adjust the pH value of the solution with sulfuric acid to be greater than 1.0, and use a high-pressure pump to transfer oxygen Air pressure into the three-phase bed, and then the reactant was heated to 90 ° C, reacted for 4 hours, when the printed circuit board was completely oxidized, filtered to obtain the filtrate. Under room temperature conditions, the extractant and the filtrate are mixed, the ratio (O/A) is 10:1, the concentration of the extractant is 10%, the pH value is adjusted to 1.0 with mineral acid, and the set stirring speed is 100r/ min, the stirrer stirs the mixed solution, through the secondary extraction and the primary stripping, the time of each stage is 1min, and the copper sulfate solution 45g/L that meets the electrowinning requirements can be obtained. Then put the copper sulfate solution into the electrolytic cell for electrowinning, the cell temperature is 20°C, the electrolyte flow rate on the cathode surface is 0.05m ³ /(m ² ·h), the current density is adjusted to 190A/m ² , and the cell voltage is 1.2 v, the purity of the obtained copper is 99.9%.

Example 3

Put the pulverized printed circuit board into the three-phase bed, then add 0.01mol/L oxygen carrier, adjust the pH value of the solution to be greater than 1.0 with sulfuric acid, press oxygen into the three-phase bed with a high-pressure pump, and then heat the reactants to 80°C, react for 4 hours, when the printed circuit board is completely oxidized, filter to obtain the filtrate. Under room temperature conditions, the extractant and the filtrate are mixed, the ratio (O/A) is 1: 1, the concentration of the extractant is 100%, the pH value is adjusted to 3.5 with mineral acid, and the set stirring speed is 1300r/ min, the stirrer stirs the mixed solution, through the secondary extraction and the primary stripping, the time of each stage is 10min, and the copper sulfate solution 50g/L that meets the electrowinning requirements can be obtained. Then put the copper sulfate solution into the electrolytic cell for electrowinning, the cell temperature is 60°C, the electrolyte flow rate on the surface of the cathode is 1.0m ³ /(m ² ·h), the current density is adjusted to 340A/m ² , and the cell voltage is 3.2 v, the purity of the obtained copper is 99.8%.

Claims (8)

1. method of extracting copper from electron wastes in turn includes the following steps:

But a) in the three-phase bed of aerating oxygen and oxygen carrier, the aqueous solution of electron wastes and oxygen carrier is mixed with weight ratio 1: 1～20, to less than 1.0, the catalyzed oxidation electron wastes is to complete reaction under the condition in 60～90 ℃ of temperature and 4～10 hours reaction times with the pH value of acid-conditioning solution;

B) post reaction mixture is filtered, with solvent extration copper is extracted from filtrate, strip with ferrous sulfate, strip liquor concentrates;

C) with electrodeposition method concentrated solution is carried out electrodeposition and extract copper, and solution behind the reservation electrodeposition;

D) solution behind the electrodeposition is regenerated recycle to the step c).

2. the method for extracting copper from electron wastes according to claim 1 is characterized in that, is oxynitride, Mn ion or Mn oxide compound at the oxygen carrier described in the step a).

3. the method for extracting copper from electron wastes according to claim 1 is characterized in that, is 0.01～5mol/L at the concentration of aqueous solution of the oxygen carrier described in the step a).

4. the method for extracting copper from electron wastes according to claim 1 is characterized in that, is sulfuric acid in the acid of the pH of the regulator solution described in step a) value.

5. the method for extracting copper from electron wastes according to claim 1 is characterized in that, also has the step that electron wastes is pulverized before step a).

6. the method for extracting copper from electron wastes according to claim 1 is characterized in that, is concentrated into more than the concentration 40g/L at the strip liquor described in the step b).

7. the method for extracting copper from electron wastes according to claim 1 is characterized in that the extraction agent that uses is Lix984 in step b).

8. the method for extracting copper from electron wastes according to claim 1 is characterized in that, is the printed circuit board (PCB) that household PC, TV, mobile phone, game machine, electronic cards or industrial equipments use at the electron wastes described in the step a).

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