CN113528838A - Acid-base combined step-by-step impurity removal method for waste circuit board copper powder - Google Patents
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- CN113528838A CN113528838A CN202110842196.9A CN202110842196A CN113528838A CN 113528838 A CN113528838 A CN 113528838A CN 202110842196 A CN202110842196 A CN 202110842196A CN 113528838 A CN113528838 A CN 113528838A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/006—Wet processes
- C22B7/007—Wet processes by acid leaching
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B13/00—Obtaining lead
- C22B13/04—Obtaining lead by wet processes
- C22B13/045—Recovery from waste materials
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B15/00—Obtaining copper
- C22B15/0063—Hydrometallurgy
- C22B15/0065—Leaching or slurrying
- C22B15/0067—Leaching or slurrying with acids or salts thereof
- C22B15/0069—Leaching or slurrying with acids or salts thereof containing halogen
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B15/00—Obtaining copper
- C22B15/0063—Hydrometallurgy
- C22B15/0065—Leaching or slurrying
- C22B15/008—Leaching or slurrying with non-acid solutions containing salts of alkali or alkaline earth metals
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B25/00—Obtaining tin
- C22B25/04—Obtaining tin by wet processes
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B25/00—Obtaining tin
- C22B25/06—Obtaining tin from scrap, especially tin scrap
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
- C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
- C22B3/10—Hydrochloric acid, other halogenated acids or salts thereof
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
- C22B3/12—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic alkaline solutions
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/006—Wet processes
- C22B7/008—Wet processes by an alkaline or ammoniacal leaching
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
The acid-base combined method for removing impurity from waste circuit board copper powder includes leaching waste circuit board copper powder in hydrochloric acid solution to selectively leach out aluminum, leaching out the residue with alkali pressure oxidation to obtain lead and tin, and hydraulic cyclone separation to obtain high quality copper smelting material. The essence of the invention is that the waste circuit board copper powder is treated by adopting a two-stage leaching and hydrocyclone mode, not only impurity metals such as aluminum, lead, tin and the like are selectively removed, but also organic matters and glass fiber components in the waste circuit board copper powder are separated, the waste circuit board copper powder is pretreated by adopting a wet leaching mode, and the harm of the impurity metals and the organic matters when the waste circuit board copper powder is recovered by pyrogenic smelting is solved.
Description
Technical Field
The invention relates to a hydrometallurgy process in the field of nonferrous metallurgy, in particular to a hydrometallurgy method for removing impurity metals in waste circuit board copper powder step by adopting a wet pretreatment mode combining acid leaching and alkaline leaching.
Background
In recent years, people have been unable to keep their production and life away from electronic and electric appliances. With the development of the Electronic industry, the progress of the technology and the expansion of the market, the upgrading speed of the Electronic and Electric Equipment is accelerated, so that the service life of the Electronic and Electric Equipment is far shorter than the actual service life of the product, and the Waste Electronic and Electric Equipment (WEEE) is rapidly increased. WEEE poses a great environmental problem and has become one of the major sources of municipal solid waste. China enters the peak period of electronic product scrapping, the theoretical scrapping amount per year exceeds 5000 thousands of electronic products, and the electronic products are increased by 20% every year. WEEE has complex components, and on one hand, the WEEE contains various valuable metal components and is an important urban mineral resource; on the other hand, it contains many toxic and harmful substances, which may cause harm to the environment and human health if not handled properly. Therefore, the development of an environment-friendly WEEE recycling technology is urgent.
The circuit board is the foundation of the electronic industry and is an important component of all electronic and electrical equipment. In recent years, the annual growth rate of the worldwide circuit board industry is 8.7%, and the growth rate of the circuit board manufacturing industry in China is as high as 14.4%. The circuit Boards produced in China each year reach 15 ten thousand tons, and the Waste Printed Circuit Boards (WPCBs) needing to be processed each year reach more than 50 ten thousand tons. WPCBs have the characteristics of high growth speed, high utilization value and great environmental hazard. The WPCBs mainly comprise resin and glass fiber and contain a large amount of metals such as copper, iron, tin, gold, palladium, silver and the like, the grade of the metals in the WPCBs is tens of times of that of common ores, and the WPCBs has extremely high resource utilization value; meanwhile, the paint contains various heavy metals and toxic and harmful substances, such as lead, cadmium, mercury, hexavalent chromium, polyvinyl chloride, halide flame retardant and the like, and the improper treatment can cause great influence on the environment and human health. Therefore, research on the aspect of WPCBs recycling is carried out, so that the WPCBs are subjected to resource and harmless treatment, and the method has important significance for promoting human sustainable development.
The WPCBs resource utilization technology mainly comprises mechanical treatment, pyrogenic treatment and wet treatment. The mechanical treatment technology is the most extensive method for recycling WPCBs, and mainly comprises the processes of disassembling, crushing, sorting and the like. Because the circuit board contains multiple electronic components, they have very big difference with the base plate in composition and structure, consequently often with electronic component disassemble back independent processing, at present, disassemble mainly by the manual work and accomplish, but along with WPCBs's increase in quantity, automatic disassembling technique is more and more paid attention to, and it is the key that realizes automatic disassembling to utilize heating device to melt the solder and make electronic component break away from. The crushing degree of circuit board is directly influencing the separation effect of metal and nonmetal, and this makes the breakage become the key link of whole mechanical treatment flow, because WPCBs comprises multilayer glass fiber cloth, reinforced resin and copper foil, has very high hardness and toughness, and traditional breaker can't obtain good effect, adopts the crushing equipment that has shearing, cutting effect can reach better effect. The sorting method mainly utilizes the difference of physical properties of materials in the WPCBs, such as magnetism, electric property, density, shape and the like, and separates metal and nonmetal in the WPCBs by means of gravity sorting, magnetoelectric sorting and the like. Mechanical treatment is often used as a pretreatment for other treatment processes because separation of the metal components cannot be achieved.
The WPCBs are subjected to mechanical treatment to obtain metal-rich multi-metal powder and non-metal powder, wherein the recovery value of the multi-metal powder is higher, and the multi-metal powder is also called waste circuit board copper powder because the copper content is highest. The method for recovering the copper powder of the waste circuit board comprises a wet method treatment process and a fire method treatment process, wherein the wet method treatment process mainly aims at recovering copper and precious metals in the copper powder of the waste circuit board, leaching is the most critical step, and wet method treatment is divided into an acid leaching method, a cyaniding method and a non-cyaniding method due to different leaching agents. The acid leaching method is that waste circuit board copper powder is treated by strong acid and strong oxidizer to strip noble metal in the waste circuit board copper powder for precipitation, other valuable metals such as copper are dissolved in acid, the precipitate is treated by nitric acid, aqua regia and the like to recover the noble metal in the waste circuit board copper powder, and the copper-containing acid solution is purified, electrolyzed and the like to obtain electrolytic copper. The cyanidation method is mainly used for recovering gold and silver in the waste circuit board copper powder, but because the copper content in the waste circuit board copper powder is very high, a large amount of copper is dissolved in the leaching process, and the leaching rate of noble metals is reduced. Since the effects of cyanide on the environment and humans are being of great public concern, research into selective leaching of waste circuit board copper powder using non-cyanide leaching agents has received considerable attention, and the thiourea and thiosulfate processes are considered to be the most promising alternatives to the cyanidation process.
Because the copper content in the waste circuit board copper powder is higher and can reach about 50 percent, the large-scale recovery of the waste circuit board copper powder in the world is usually carried out in a large-scale pyrometallurgical copper smelting plant at present. In the pyrometallurgical copper smelting process, metals such as tin, lead, zinc, aluminum and the like in the waste circuit board copper powder can be dispersed into slag, flue gas and copper matte, so that the recovery rate of copper is reduced, the quality of cathode copper is influenced, and the stability of a copper smelting system is influenced. At present, the research on the separation and recovery of these metals is relatively rare, and these valuable metal resources are wasted because the copper powder is often removed as impurity metal in the process of recovering the waste circuit board copper powder. In addition, the substrate of the waste circuit board contains a large amount of organic matters, partial metal is still wrapped by organic matters such as epoxy resin, flame retardant and the like due to insufficient dissociation in the mechanical pretreatment process, and toxic and harmful gases such as dibenzodioxin, dibenzofuran and the like can be generated in the smelting process, so that the environment is greatly polluted.
Disclosure of Invention
In order to overcome the harm of impurity metals in the pyrogenic process recovery process of waste circuit board copper powder, the invention provides a hydrometallurgical method for treating the waste circuit board copper powder by adopting a wet step-by-step leaching mode combining hydrochloric acid leaching and alkaline pressure oxidation leaching, and the hydrometallurgical method has the advantages of high recovery rate of the impurity metals of aluminum, lead and tin and complete separation of organic matters and glass fibers.
In order to achieve the aim, the invention adopts the technical scheme that: leaching waste circuit board copper powder in a hydrochloric acid solution to dissolve aluminum in the form of aluminum chloride into a leaching solution, and simultaneously primarily enriching copper; and selectively dissolving lead and tin in the dealuminized slag by adopting an alkaline pressure oxidation leaching mode, and obtaining the highly enriched copper in the alkaline leaching slag by adopting a cyclone separation mode. The essence of the invention is that hydrochloric acid leaching is adopted to realize selective removal of aluminum in the waste circuit board copper powder, alkaline pressure oxidation leaching is adopted to realize high-efficiency separation of lead and tin, and finally a hydraulic cyclone separation mode is adopted to remove organic matters and glass fiber components; these processes are closely related, and neither process alone can achieve the desired effect of wet pretreatment of waste circuit board copper powder.
The specific technological process and parameters are as follows:
1 hydrochloric acid leach
Leaching waste circuit board copper powder in a hydrochloric acid solution; preparing a hydrochloric acid solution with the molar concentration of 0.5-2.0 mol/L, adding waste circuit board copper powder according to the liquid-solid ratio of the liquid volume L to the solid weight Kg of 2-8: 1, controlling the temperature to be 30-90 ℃, reacting for 1-4 h, then realizing solid-liquid separation by adopting a vacuum filtration mode, recovering aluminum from acid leaching solution, and taking dealuminized slag as a subsequent alkaline leaching raw material. The main chemical reactions taking place during the hydrochloric acid leaching are as follows:
2Al + 6HCl = 3AlCl3 + 3H2 （1）
2 alkaline pressure oxidation leaching
Introducing oxygen into the dealuminized slag in an alkaline system, and carrying out pressure oxidation leaching; preparing a sodium hydroxide solution with the molar concentration of 1.5-3.0 mol/L, adding dealuminization slag according to the liquid-solid ratio of the liquid volume L to the solid weight Kg of 2-8: 1, simultaneously adding sodium nitrate with the weight of 0.25-1.0% of that of waste circuit board copper powder as a catalyst, adding the mixed slurry into a stainless steel high-pressure reaction kettle, controlling the reaction temperature to be 150-250 ℃ and the oxygen partial pressure to be 2.0-4.0 MPa for reaction for 2-4 h, cooling to below 50 ℃ after the reaction is finished, realizing solid-liquid separation by adopting a vacuum filtration mode, recovering lead and tin from alkaline leaching solution, and selecting the alkaline leaching slag to be used as a high-quality raw material for pyrometallurgical copper smelting; the main chemical reactions that take place during alkaline pressure oxidation leaching are as follows:
3 hydrocyclone separation
The alkaline leaching residue is separated by hydraulic cyclone; controlling the granularity of the oxidized leaching slag to be 0.074-5 mm, pulping the oxidized leaching slag by water, introducing the pulped oxidized leaching slag into a hydrocyclone for separation, controlling the ore feeding pressure to be 0.2-1.0 MPa and the ore feeding concentration to be 2-10%, enabling the copper concentrate to enter underflow and the organic matters and glass fibers to enter overflow.
The invention is suitable for treating waste circuit board copper powder produced in the process of crushing and sorting waste circuit boards, and the ranges of the main components are (%): cu40.0-80.0%, Al1.0-10.0%, Sn4.0-18.0%, Pb4.0-18.0%, Au 10-200 g/t and Ag 500-2000 g/t.
Compared with the traditional pretreatment method of waste circuit board copper powder, the method has the following advantages: 1. according to the invention, the waste circuit board copper powder is treated by adopting a wet pretreatment mode combining hydrochloric acid leaching and alkaline pressure oxidation leaching, aluminum, lead and tin in the waste circuit board copper powder are effectively removed, and leached residues are separated by hydrocyclone to remove organic matters and glass fibers, so that a high-quality raw material is provided for pyrometallurgical copper smelting; 2. the method comprises the following steps of leaching in a hydrochloric acid solution to realize high-efficiency removal of aluminum in the copper powder of the waste circuit board, wherein the removal rate of the aluminum reaches more than 97.2%; 3. the lead and tin in the dealuminized slag are selectively leached out by alkaline pressure oxidation leaching, and the leaching rates respectively reach over 86.6 percent and 93.8 percent; 4. organic matters and glass fiber components in the alkaline leaching residues are removed by adopting a hydraulic cyclone separation method, so that copper is highly enriched and can be used as a high-quality copper smelting raw material by a pyrogenic process; 5. the invention has the advantages of stable technical indexes of the process, low labor intensity, low production cost and the like.
Drawings
FIG. 1: the invention is a process flow diagram.
Detailed Description
Example 1
The waste circuit board copper powder produced in the process of crushing and sorting waste circuit boards of certain enterprises in China comprises the following main components in percentage by mass: cu44.6, Al2.5, Sn9.2, Pb5.1, Au20g/t and Ag700 g/t. Hydrochloric acid, sodium hydroxide and sodium nitrate are all industrial grade reagents, and the mass percentage content of the reagents is not less than 98.0%.
Preparing a hydrochloric acid solution with the molar concentration of 1.5mol/L, adding waste circuit board copper powder according to the liquid-solid ratio (the ratio of liquid volume to solid weight) of 5:1, raising the temperature to 80 ℃, reacting for 2 hours at the stirring speed of 600rpm, and then realizing solid-liquid separation by adopting a vacuum filtration mode, wherein the leaching rate of aluminum is more than 97.2%; preparing a sodium hydroxide solution with the molar concentration of 2.5mol/L, adding dealuminization slag according to the liquid-solid ratio of the liquid volume L to the solid weight Kg of 5:1, simultaneously adding sodium nitrate with the weight of 0.4 percent of that of waste circuit board copper powder as a catalyst, adding the mixed slurry into a stainless steel high-pressure reaction kettle, controlling the reaction temperature to be 200 ℃ and the oxygen partial pressure to be 3.0MPa for reaction for 3 hours, cooling to below 50 ℃ after the reaction is finished, realizing solid-liquid separation by adopting a vacuum filtration mode, and respectively achieving the leaching rates of lead and tin to be above 86.6 percent and 93.8 percent; controlling the granularity of the oxidized leaching slag to be 0.074-1 mm, pulping by using water, then conveying the pulped oxidized leaching slag into a hydraulic cyclone for separation, controlling the feeding pressure to be 0.4MPa and the feeding concentration to be 8%, wherein in the separation process, copper concentrate enters underflow, and a mixture of organic matters and glass fibers enters overflow.
Claims (1)
1. A method for removing impurities from waste circuit board copper powder step by step through acid-base combination is characterized by comprising the following steps:
(1) hydrochloric acid leaching
Preparing a hydrochloric acid solution with the molar concentration of 0.5-2.0 mol/L, adding waste circuit board copper powder according to the liquid-solid ratio of the liquid volume L to the solid weight Kg of 2-8: 1, controlling the temperature to be 30-90 ℃, reacting for 1-4 h, then realizing solid-liquid separation by adopting a vacuum filtration mode, recovering aluminum from an acid leaching solution, and taking dealuminized slag as a subsequent alkaline leaching raw material;
(2) alkaline pressure oxidation leaching
Preparing a sodium hydroxide solution with the molar concentration of 1.5-3.0 mol/L, adding dealuminization slag according to the liquid-solid ratio of the liquid volume L to the solid weight Kg of 2-8: 1, simultaneously adding sodium nitrate with the weight of 0.25-1.0% of that of waste circuit board copper powder as a catalyst, adding the mixed slurry into a stainless steel high-pressure reaction kettle, controlling the reaction temperature to be 150-250 ℃ and the oxygen partial pressure to be 2.0-4.0 MPa for reaction for 2-4 h, cooling to below 50 ℃ after the reaction is finished, realizing solid-liquid separation by adopting a vacuum filtration mode, recovering lead and tin from alkaline leaching solution, and selecting the alkaline leaching slag to be used as a high-quality raw material for pyrometallurgical copper smelting;
(3) hydrocyclone separation
Controlling the granularity of the oxidized leaching slag to be 0.074-5 mm, pulping the oxidized leaching slag by water, introducing the pulped oxidized leaching slag into a hydrocyclone for separation, controlling the ore feeding pressure to be 0.2-1.0 MPa and the ore feeding concentration to be 2-10%, enabling the copper concentrate to enter underflow and the organic matters and glass fibers to enter overflow.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000031339A (en) * | 1998-07-16 | 2000-01-28 | Matsushita Electric Ind Co Ltd | Lightning-resistant transmitting body and terminal network controller mounted with the same |
| CN105779770A (en) * | 2016-03-10 | 2016-07-20 | 中南大学 | Method for recycling valuable metal in waste circuit board |
| CN106381392A (en) * | 2016-09-30 | 2017-02-08 | 中南大学 | Chemical mineral dressing pretreatment method for waste printed circuit board multi-metal powder |
| US20200262712A1 (en) * | 2017-12-30 | 2020-08-20 | Beijing University Of Technology | A Method of Pretreatment and Bromine Recovery of PCB Incineration Ash |
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2021
- 2021-07-26 CN CN202110842196.9A patent/CN113528838A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000031339A (en) * | 1998-07-16 | 2000-01-28 | Matsushita Electric Ind Co Ltd | Lightning-resistant transmitting body and terminal network controller mounted with the same |
| CN105779770A (en) * | 2016-03-10 | 2016-07-20 | 中南大学 | Method for recycling valuable metal in waste circuit board |
| CN106381392A (en) * | 2016-09-30 | 2017-02-08 | 中南大学 | Chemical mineral dressing pretreatment method for waste printed circuit board multi-metal powder |
| US20200262712A1 (en) * | 2017-12-30 | 2020-08-20 | Beijing University Of Technology | A Method of Pretreatment and Bromine Recovery of PCB Incineration Ash |
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