CN117943390A - Method for removing chlorine in electronic waste smoke dust by pretreatment process - Google Patents

Abstract

The invention belongs to the technical field of solid waste treatment, and specifically relates to a method for removing chlorine from electronic waste smoke by using a pretreatment process, wherein concentrated sulfuric acid is used to perform closed ventilation granulation and closed ventilation storage maturation on high-chlorine electronic waste smoke (chlorine>0.5%), and gas spray absorption treatment is used to convert it into harmless calcium chloride liquid, and after granulation reaction and maturation reaction, chlorine in the raw material is converted into a reactant and volatilized, so as to ensure that the chlorine content of the subsequently produced zinc precipitation slag meets the raw material standard requirements of the electrolytic zinc enterprise, after 2-3 days of storage and maturation, the material is stirred and leached at room temperature under the condition of a liquid-solid ratio of 10:1, and zinc powder is used to replace copper in the filtrate after pressure filtration to obtain sponge copper, and then the zinc-containing filtrate filtered by pressure filtration is precipitated by soda ash to obtain low-chlorine zinc slag (chlorine≦0.5%), the copper content of the sponge copper obtained by the process is as high as 55%, the zinc content of basic zinc carbonate is about 34%, and the chlorine removal rate is above 85%, which can be directly used by electrolytic zinc enterprises without adverse effects.

Description

A method for removing chlorine from electronic waste smoke using a pretreatment process

Technical Field

The invention belongs to the technical field of solid waste treatment, and in particular relates to a method for removing chlorine from electronic waste smoke by utilizing a pretreatment process.

Background technique

Electronic waste is generally treated by chemical and physical methods. The chemical method includes disassembly, crushing, wet treatment and fire treatment. The physical method adopts the method of disassembly, crushing and small workshops repairing and selling to villages. However, due to the late start of electronic waste treatment in my country, the technology is far behind that of Europe, the United States and surrounding developed countries. Therefore, chemical treatment is more often used when facing greater economic benefits. In the end, whether it is wet or fire, there is a fire smelting process when the non-ferrous metal recovery is finally completed. Especially when multiple metals are smelted together, the smoke and dust generated become a secondary pollution source. Because the smoke and dust contain volatiles of flame retardant materials, polyvinyl chloride and other materials, and the total metal content is lower than that of previous smelting and recycling processes, garbage disposal and recycling companies are unwilling to further recycle smoke and dust. In addition, this type of smoke contains high zinc content. The recovery benefits of zinc are interfered by chloride ions and cannot be smoothly used as raw materials for electro-zinc enterprises. Chlorine content has also become an inevitable problem in the recycling of smoke and dust resources.

At present, small vendors have become the main force in recycling electronic waste. The technology they use is simple and crude. First, after simple treatment, it flows into low-income families and rural areas; second, after being disassembled, the components that still have certain value are refurbished and modified, and then flow into the market. Some people rely on only a hammer and an acid pool to continuously pan for gold in electronic waste. While getting rich, they cause many environmental problems, leading to the escape of toxic gases, the infiltration of wastewater into the ground, and the discharge into the river. Some parts go directly into the melting furnace. During the process, because the materials contain a large amount of brominated flame retardants, dioxins are produced. The organic toxic components in the smoke and dust pollute the environment and water bodies more seriously, especially the smoke and dust have a strong pungent smell. Long-term storage poses a threat to the health of surrounding residents. In addition, the downstream enterprises that general enterprises receive are often only the ingredients for the production of high-chlorine smoke and dust. The presence of chloride ions causes great trouble to the market equipment and processes. After entering the electrolytic zinc enterprise, in addition to causing corrosion to the equipment, it also causes rapid corrosion to the anode plates of the electrolysis process and affects the decline in electrical efficiency and output.

Summary of the invention

The purpose of the present invention is to provide a method for removing chlorine from electronic waste smoke by using a pretreatment process, utilizing the surface gaps of particles to release the reaction product hydrogen chloride gas to achieve the purpose of removing chlorine from the smoke, ensuring that zinc-containing materials are converted into low-chlorine raw materials for use by all zinc electrolysis industries, so as to solve the problems in the prior art raised in the above-mentioned background technology.

To achieve the above object, the present invention adopts the following technical scheme: a method for removing chlorine from electronic waste smoke by using a pretreatment process, comprising: subjecting smoke and concentrated sulfuric acid to a granulation reaction under a closed ventilation and slightly negative pressure to obtain particles, during which the reaction generates hydrogen chloride gas, which enters a spray tower through ventilation and is absorbed by lime liquid; placing the particles into a closed ventilation stack of a shovel-type leaching tank for maturation, continuing the reaction to volatilize hydrogen chloride gas, and the generated gas enters a lime liquid spray tower through negative pressure ventilation and is absorbed; mixing the maturated particles with water for leaching, filtering by vacuum filtration after the leaching is completed, washing the leached residue to obtain a filtrate; adding zinc powder to the filtrate according to the number of grams and liters of copper contained to replace sponge copper, vacuum filtration is performed after the replacement reaction is completed to separate the sponge copper from the liquid, and soda ash is weighed after filtration for neutralization reaction to produce basic zinc carbonate; vacuum filtration is performed on the basic zinc carbonate to obtain zinc-containing slag, and the zinc slag is washed with washing water; the filtrate of the basic zinc carbonate filtration contains less than 0.5g/1 of chlorine, and is returned for continued leaching and recycled.

Preferably, the smoke and concentrated sulfuric acid are subjected to a granulation reaction under a closed ventilation and slightly negative pressure to obtain particles, including: putting the mixed smoke into a granulation disk, gradually and continuously adding small amounts of concentrated sulfuric acid, and granulating the smoke while the granulation disk rotates at a speed of 15-20r/min.

Preferably, the mass ratio of the smoke to concentrated sulfuric acid is 1:0.68.

Preferably, the aging reaction time is 3-4 days.

Preferably, the liquid-to-solid ratio of the particles to water is 10:1.

Preferably, the mixing and leaching of the matured particles with water comprises: putting the particles and water into a stirrer, and stirring and leaching at room temperature for 1.5 hours at a rotation speed of 90-100 r/min.

Preferably, the replacement reaction time is 45-50 minutes.

Preferably, the mass ratio of soda ash to smoke is 0.77:1.

Preferably, the neutralization reaction ends at a pH value of 6.0-6.5.

Preferably, the mass ratio of the zinc slag to the wash water is 1:2.

Technical effects and advantages of the present invention: The present invention proposes a method for removing chlorine from electronic waste smoke by using a pretreatment process, which has the following advantages compared with the prior art:

The invention uses concentrated sulfuric acid to perform closed ventilation granulation and closed ventilation storage maturation on high-chlorine electronic waste smoke (chlorine>0.5%), and gas spray absorption treatment is converted into harmless calcium chloride liquid. After granulation reaction and maturation reaction, chlorine in the raw material is converted into reactants and volatilized, so as to ensure that the chlorine content of the subsequently produced zinc precipitation slag meets the raw material standard requirements of the electrolytic zinc enterprise. After 2-3 days of storage and maturation, the material is stirred and leached at room temperature under the condition of a liquid-solid ratio of 10:1, and zinc powder is used to replace copper in the filtrate after pressure filtration to obtain sponge copper. Soda ash is used to precipitate the zinc-containing filtrate after pressure filtration to obtain low-chlorine zinc slag (chlorine≤0.5%), and the chlorine content of the liquid after zinc precipitation is less than 0.5g/l, which can be returned for leaching and recycling. The copper content of the sponge copper obtained by the process is as high as 55%, the zinc content of basic zinc carbonate is about 34%, and the chlorine removal rate is above 85%, which can be directly used by electrolytic zinc enterprises without adverse effects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of a method for removing chlorine from electronic waste dust using a pretreatment process according to the present invention.

Detailed ways

The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

In the embodiment of the present invention, a method for removing chlorine from electronic waste dust by using a pretreatment process is provided, wherein concentrated sulfuric acid is used to perform closed ventilation granulation and closed ventilation storage maturation on high-chlorine electronic waste dust (chlorine>0.5%), and gas spray absorption treatment is converted into harmless calcium chloride liquid, and after granulation reaction and maturation reaction, the chlorine in the raw material is converted into reactants and volatilized, so as to ensure that the chlorine content of the zinc precipitation slag produced subsequently meets the raw material standard requirements of the electro zinc enterprise, and after 2-3 days of storage and maturation, the material is stirred and leached at room temperature under the condition of a liquid-solid ratio of 10:1, and the filtrate after pressure filtration uses zinc powder to replace copper to obtain sponge copper, and then the zinc-containing filtrate filtered by pressure filtration is precipitated with soda ash to obtain low-chlorine zinc slag (chlorine≦0.5%), and the copper content of the sponge copper obtained by the process is as high as 55%, the zinc content of basic zinc carbonate is about 34%, and the chlorine removal rate is above 85%, which can be directly used by electro zinc enterprises without adverse effects. The following will be specifically described in conjunction with the embodiments.

Example 1

The present invention provides a method for removing chlorine from electronic waste smoke using a pretreatment process as shown in FIG1 , comprising:

Step 1: The smoke and concentrated sulfuric acid (the mass ratio of smoke and concentrated sulfuric acid is 1:0.68) are subjected to granulation reaction under a closed ventilation and slightly negative pressure to obtain particles. In the process, hydrogen chloride gas is generated by the reaction, and the gas enters the spray tower through ventilation and is absorbed by the lime liquid;

Specifically, the mixed smoke is put into a granulation disk, and concentrated sulfuric acid is gradually and continuously added in small amounts. The granulation disk rotates at a speed of 15 r/min to granulate the smoke.

Among them, concentrated sulfuric acid has, Strong acidity: Concentrated sulfuric acid is a strong acid with very high acidity. It can react with many substances, including metals, oxidants, and alkalis. Due to its strong acidity, concentrated sulfuric acid needs to be handled with care when used and handled to avoid injury and damage. Corrosiveness: Concentrated sulfuric acid is extremely corrosive and can corrode a variety of materials, including metals, plastics, and fibers. Therefore, special safety measures need to be taken when handling and storing concentrated sulfuric acid, such as wearing protective glasses, gloves, and protective clothing. Oxidizing property: Concentrated sulfuric acid also has strong oxidizing properties and can react with many oxidizable substances. This makes concentrated sulfuric acid an important catalyst or reactant in many chemical reactions. Widely used: Concentrated sulfuric acid is widely used in industry and laboratories. It is used as a catalyst, dehydrating agent, cleaning agent, and reaction medium.

The smoke mentioned in the above steps is electronic waste smoke. Electronic waste contains hundreds of substances such as copper, zinc, lead, tin, gold, silver, palladium, platinum, lithium, cadmium, polybrominated diphenyl ethers and polybrominated biphenyls, 50% of which are harmful to the human body. If they are not handled properly during the recycling process, they will seriously pollute the environment and endanger human health. More than 75% of the materials in electronic waste are useful. The waste gas, waste liquid and waste residue generated by the random discharge during the recycling process seriously damage the surrounding environment. This kind of smoke is generated when the metal casting alloy is processed in the medium frequency furnace.

Step 2: Put the particles into the closed exhaust stack of the lifting plate leaching tank for maturation (3 days), continue to react and volatilize the hydrogen chloride gas, and the generated gas is sucked into the lime liquid spray tower by negative pressure exhaust;

Among them, the leaching tank refers to a liquid-solid reactor that realizes leaching operations at normal pressure and a temperature below 373K. The leaching tanks widely used in non-ferrous metal extraction metallurgy mainly include percolation tanks, compressed air stirring tanks, mechanical stirring tanks, air and mechanical combined stirring tanks and Kamer towers. The tank body is usually made of concrete or steel plates, lined with acid-resistant materials such as lead sheets, tiles, epoxy fiberglass, etc.

For the lime liquid spray tower, the angle of the spray pipe can be adjusted so that the lime liquid can better contact with the gas, thereby improving the absorption efficiency, increasing the contact area between the lime liquid and the gas, and improving the absorption efficiency. Properly increasing the gas flow rate can increase the relative speed between the gas and the lime liquid, speed up the reaction rate, and improve the absorption efficiency of the lime liquid. It is recommended to set the gas flow rate at 2-3 m/s.

In addition, the air intake duct should be designed reasonably to avoid the influence of air on lime liquid. The air intake duct can be set at the bottom of the spray tower to allow air to enter from the bottom instead of directly contacting the lime liquid, which can reduce the interference of pollutants in the air on the lime liquid. According to the actual use environment, select filler materials with good corrosion resistance. For example, stainless steel, ceramics and other materials have strong corrosion resistance and oxidation resistance, which is conducive to maintaining the stability of lime liquid and improving absorption efficiency.

Step 3: Mix the matured particles with water for leaching (the liquid-to-solid ratio of particles to water is 10:1), filter using vacuum filtration after leaching, wash the leached residue, and obtain a filtrate;

Among them, vacuum filtration is a method of treating solid waste. It uses a vacuum pump to extract suspended particles in the filter medium and separate them, thereby achieving the treatment and disposal of solid waste. The main features of vacuum filtration are large processing capacity, good processing effect, low energy consumption, and easy operation.

Specifically, the particles and water were put into a stirrer, and the stirrer was stirred and leached at room temperature for 1.5 hours at a rotation speed of 90 r/min.

Among them, the agitator is used to mix two or more liquids evenly. Its main components include a mixing tank and a stirring paddle. When the current passes through the motor in the mixing tank, it will generate a rotational force, causing the stirring paddle to rotate. The rotation of the stirring paddle will drive the liquid and mix it together. Preferably, the paddle diameter: the mixing barrel diameter = 0.45.

Step 4: zinc powder (zinc powder: total metal content in copper leaching solution = 1.3) is added to the filtrate according to the amount of copper in grams per liter to replace the sponge copper. After the replacement reaction (45 minutes), vacuum filtration is performed to separate the sponge copper from the liquid. After filtration, soda ash is weighed for neutralization reaction to produce basic zinc carbonate; illustratively, the mass ratio of soda ash to smoke is 0.77:1, and the neutralization reaction is completed at a pH value of 6.0-6.5.

Among them, vacuum filtration is a method for separating sponge copper from liquid. This method uses the difference in atmospheric pressure to place the sponge copper and liquid to be separated in a container, and then extract the air in the container to extract the liquid, while the sponge copper remains at the bottom of the container due to gravity. This method is easy to operate and can be used to separate a large amount of sponge copper. Similarly, other methods can be used to achieve this goal.

Step 5: Vacuum filter and separate basic zinc carbonate to obtain zinc-containing slag, and wash the zinc slag with washing water (the mass ratio of zinc slag to washing water is 1:2).

Specifically, vacuum filtration separation uses high-efficiency vacuum filtration equipment, such as belt pressure filters or ultra-high-efficiency centrifuges. These devices can quickly and thoroughly remove impurities and improve the purity of zinc slag. When selecting the filter medium, factors such as its chemical inertness and pore size need to be considered to avoid affecting the subsequent washing and extraction effects. Washing of zinc slag: Use appropriate detergents or cleaning liquids, such as organic solvents, sodium hydroxide solutions, etc. to clean the zinc slag. When selecting detergents or cleaning liquids, it is necessary to consider whether they can effectively remove pollutants on the surface of the zinc slag, and at the same time, they cannot destroy the internal structure of the zinc slag. In addition, in order to avoid environmental pollution, environmentally friendly detergents or cleaning liquids should be selected. Extraction: For the washed zinc slag, further extraction is required. Using solvent extraction, the zinc slag is dissolved in an appropriate solvent, and then pure zinc powder is obtained by evaporation concentration, cooling crystallization, etc. When selecting a solvent, it is necessary to consider whether it can fully dissolve the metal elements in the zinc slag, and also pay attention to whether it will cause harm to the environment and human health.

Step 6: The filtrate of basic zinc carbonate extraction contains chlorine below 0.5 g/1 and is returned for further leaching and recycling.

In this embodiment, industrial grade 98 acid is used, and granulation reaction is carried out under closed ventilation and slight negative pressure. During the process, the reaction generates hydrogen chloride gas, and the gas enters the spray tower through ventilation and is absorbed by lime liquid. After granulation, it enters the closed ventilation storage and slaking of the copying plate type leaching tank, and the reaction continues to volatilize hydrogen chloride gas. The generated gas is absorbed by negative pressure ventilation entering the lime liquid spray tower. After granulation reaction and slaking reaction, the chlorine in the raw material is converted into reactants and volatilized, ensuring that the chlorine content of the zinc precipitate slag produced later meets the raw material standard requirements of the electro-zinc enterprise. The copper content in the sponge copper obtained by this process is as high as 55%, the zinc content in basic zinc carbonate is about 34%, and the chlorine removal rate is more than 85%. The chlorine content in the low-chlorine circulating liquid returned to the process is less than 0.01g/l, which meets the low concentration requirement of chlorine in the process.

Example 2

The present invention provides a method for removing chlorine from electronic waste smoke using a pretreatment process as shown in FIG1 , comprising:

Step 1: The smoke and concentrated sulfuric acid (the mass ratio of smoke and concentrated sulfuric acid is 1:0.68) are subjected to granulation reaction under a closed ventilation and slightly negative pressure to obtain particles. In the process, hydrogen chloride gas is generated by the reaction, and the gas enters the spray tower through ventilation and is absorbed by the lime liquid;

Specifically, the mixed smoke is put into a granulation disk, and concentrated sulfuric acid is gradually and continuously added in small amounts. The granulation disk rotates at a speed of 18 r/min to granulate the smoke.

Step 2: Put the particles into the closed exhaust stack of the lifting plate leaching tank for maturation (3 days), continue to react and volatilize the hydrogen chloride gas, and the generated gas is sucked into the lime liquid spray tower by negative pressure exhaust;

Step 3: Mix the matured particles with water for leaching (the liquid-to-solid ratio of particles to water is 10:1), filter using vacuum filtration after leaching, wash the leached residue, and obtain a filtrate;

Specifically, the particles and water were put into a stirrer, and the stirrer was stirred and leached at room temperature for 1.5 hours at a rotation speed of 95 r/min.

Step 4: zinc powder is added to the filtrate according to the amount of copper in grams per liter to replace the sponge copper. After the replacement reaction (48 minutes), vacuum filtration is performed to separate the sponge copper from the liquid. After filtration, soda ash is weighed to carry out neutralization reaction to produce basic zinc carbonate; illustratively, the mass ratio of soda ash to smoke is 0.77:1, and the neutralization reaction is completed at a pH value of 6.0-6.5.

Step 5: vacuum filter and separate basic zinc carbonate to obtain zinc-containing slag, and wash the zinc slag with washing water (the mass ratio of zinc slag to washing water is 1:2);

Step 6: The filtrate of basic zinc carbonate extraction contains chlorine below 0.5 g/1 and is returned for further leaching and recycling.

In this embodiment, industrial grade 98 acid is used, and granulation reaction is carried out under closed ventilation and slight negative pressure. During the process, the reaction generates hydrogen chloride gas, and the gas enters the spray tower through ventilation and is absorbed by lime liquid. After granulation, it enters the closed ventilation storage and slaking of the copying plate type leaching tank, and the reaction continues to volatilize hydrogen chloride gas. The generated gas is absorbed by negative pressure ventilation entering the lime liquid spray tower. After granulation reaction and slaking reaction, the chlorine in the raw material is converted into reactants and volatilized, ensuring that the chlorine content of the zinc precipitate slag produced later meets the raw material standard requirements of the electro-zinc enterprise. The copper content in the sponge copper obtained by this process is as high as 55%, the zinc content in basic zinc carbonate is about 34%, and the chlorine removal rate is more than 85%. The chlorine content in the low-chlorine circulating liquid returned to the process is less than 0.01g/l, which meets the low concentration requirement of chlorine in the process.

Example 3

The present invention provides a method for removing chlorine from electronic waste smoke using a pretreatment process as shown in FIG1 , comprising:

Step 1: The smoke and concentrated sulfuric acid (the mass ratio of smoke and concentrated sulfuric acid is 1:0.68) are subjected to granulation reaction under a closed ventilation and slightly negative pressure to obtain particles. In the process, hydrogen chloride gas is generated by the reaction, and the gas enters the spray tower through ventilation and is absorbed by the lime liquid;

Specifically, the mixed smoke is put into a granulation disk, and concentrated sulfuric acid is gradually and continuously added in small amounts. The granulation disk rotates at a speed of 20 r/min to granulate the smoke.

Step 2: Put the particles into the closed exhaust stacking tank of the lifting plate type for maturation (4 days), continue to react and volatilize the hydrogen chloride gas, and the generated gas is sucked into the lime liquid spray tower by negative pressure exhaust and absorbed;

Step 3: Mix the matured particles with water for leaching (the liquid-to-solid ratio of particles to water is 10:1), filter using vacuum filtration after leaching, wash the leached residue, and obtain a filtrate;

Specifically, the particles and water were put into a stirrer, and the stirrer was stirred and leached at room temperature for 1.5 hours at a rotation speed of 100 r/min.

Step 4: zinc powder is added to the filtrate according to the amount of copper in grams per liter to replace the sponge copper. After the replacement reaction (50 minutes), vacuum filtration is performed to separate the sponge copper from the liquid. After filtration, soda ash is weighed to carry out neutralization reaction to produce basic zinc carbonate; illustratively, the mass ratio of soda ash to smoke is 0.77:1, and the neutralization reaction is completed at a pH value of 6.0-6.5.

Step 5: vacuum filter and separate basic zinc carbonate to obtain zinc-containing slag, and wash the zinc slag with washing water (the mass ratio of zinc slag to washing water is 1:2);

Step 6: The filtrate of basic zinc carbonate extraction contains chlorine below 0.5 g/1 and is returned for further leaching and recycling.

In this embodiment, industrial grade 98 acid is used, and granulation reaction is carried out under closed ventilation and slight negative pressure. During the process, the reaction generates hydrogen chloride gas, and the gas enters the spray tower through ventilation and is absorbed by lime liquid. After granulation, it enters the closed ventilation storage and slaking of the copying plate type leaching tank, and the reaction continues to volatilize hydrogen chloride gas. The generated gas is absorbed by negative pressure ventilation entering the lime liquid spray tower. After granulation reaction and slaking reaction, the chlorine in the raw material is converted into reactants and volatilized, ensuring that the chlorine content of the zinc precipitate slag produced later meets the raw material standard requirements of the electro-zinc enterprise. The copper content in the sponge copper obtained by this process is as high as 55%, the zinc content in basic zinc carbonate is about 34%, and the chlorine removal rate is more than 85%. The chlorine content in the low-chlorine circulating liquid returned to the process is less than 0.01g/l, which meets the low concentration requirement of chlorine in the process.

The present invention uses concentrated sulfuric acid to directly granulate, and utilizes the gaps on the surface of the particles to release the reaction product, hydrogen chloride gas, to achieve the purpose of removing chlorine from smoke, ensuring that the zinc-containing material is converted into a low-chlorine raw material for use in all electro-zinc industries. This process has the characteristics of efficient chlorine removal, while replacing copper and precipitating zinc to obtain valuable metals, which can achieve efficient recovery of non-ferrous metals in electronic waste, and can also perform dechlorination pretreatment on raw materials in non-ferrous metal metallurgy. The liquid can be kept in a low-chlorine state and can be recycled, ensuring cost feasibility and not generating waste liquid discharge.

Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A method for removing chlorine in electronic waste smoke dust by using a pretreatment process, which is characterized by comprising the following steps:

granulating the smoke dust and the concentrated sulfuric acid under the condition of closed air draft and micro negative pressure to obtain particles, reacting in the process to generate hydrogen chloride gas, and allowing the gas to enter a spray tower through air draft to be absorbed by lime liquid;

Putting the particles into a shoveling plate type leaching tank, performing airtight air draft, piling up and curing, continuing to react and volatilize hydrogen chloride gas, and enabling the generated gas to be sucked into a lime liquid spray tower by negative pressure air draft;

mixing and leaching the cured particles with water, filtering after leaching, and washing leaching residues to obtain filtrate;

zinc powder is added into the filtrate according to gram liter of copper to replace sponge copper, vacuum suction filtration is carried out after the replacement reaction is finished to separate the sponge copper from liquid, and sodium carbonate is weighed after suction filtration to carry out neutralization reaction to generate basic zinc carbonate;

Vacuum filtering and separating the basic zinc carbonate to obtain zinc-containing slag, and washing the zinc slag by washing water;

The filtrate of the leaching of the basic zinc carbonate returns to the leaching state under 0.5g/1 for recycling.

2. The method for removing chlorine from electronic waste smoke by pretreatment process according to claim 1, wherein the granulating reaction of smoke and concentrated sulfuric acid under the condition of closed draft micro negative pressure to obtain particles comprises:

And (3) putting the mixed smoke dust into a granulating disc, gradually and continuously and slightly putting concentrated sulfuric acid, and granulating the smoke dust under the condition that the granulating disc rotates at the rotating speed of 15-20 r/min.

3. The method for removing chlorine from electronic waste smoke by pretreatment process according to claim 2, wherein the mass ratio of smoke to concentrated sulfuric acid is 1:0.68.

4. The method for removing chlorine from electronic waste smoke by pretreatment process according to claim 1, wherein the reaction time of said curing is 3-4 days.

5. The method for removing chlorine from electronic waste smoke by pretreatment process according to claim 1, wherein the liquid-solid ratio of said particles to water is 10:1.

6. A method for removing chlorine from electronic waste smoke by pretreatment process according to claim 1, wherein said mixing and leaching of cured particles with water comprises:

The particles and water are put into a stirrer, and the stirrer is stirred and leached for 1.5 hours at normal temperature under the condition of the rotating speed of 90-100 r/min.

7. The method for removing chlorine from electronic waste smoke by pretreatment process according to claim 1, wherein said displacement reaction time is 45-50 minutes.

8. The method for removing chlorine from electronic waste smoke by using pretreatment process as set forth in claim 1, wherein: the mass ratio of the sodium carbonate to the smoke dust is 0.77:1.

9. The method for removing chlorine from electronic waste smoke by pretreatment process according to claim 1, wherein said neutralization reaction is terminated at a pH of 6.0-6.5.

10. The method for removing chlorine from electronic waste smoke by using a pretreatment process according to claim 1, wherein the mass ratio of zinc dross to washing water is 1:2.