CN113528841B - Method for removing impurity metals from waste circuit board copper powder through ball milling - Google Patents
Method for removing impurity metals from waste circuit board copper powder through ball milling Download PDFInfo
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- CN113528841B CN113528841B CN202110842202.0A CN202110842202A CN113528841B CN 113528841 B CN113528841 B CN 113528841B CN 202110842202 A CN202110842202 A CN 202110842202A CN 113528841 B CN113528841 B CN 113528841B
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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
- C22B21/00—Obtaining aluminium
- C22B21/0015—Obtaining aluminium by wet processes
- C22B21/0023—Obtaining aluminium by wet processes 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
- 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
- C22B3/08—Sulfuric acid, other sulfurated acids or salts thereof
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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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
A method for removing impurity metals from waste circuit board copper powder by ball milling separation comprises leaching the waste circuit board copper powder in a ball milling tank with sulfuric acid solution to selectively leach aluminum and iron; after drying the obtained leaching slag, separating lead and tin into fine particles by adopting a mechanical screening mode, and enriching copper into coarse particles; and finally, treating the coarse particles in a potential-controlled hydrochloric acid oxidation leaching manner, and deeply removing lead and tin in the coarse particles to further enrich the copper. The essence of the invention is that the impurity metal in the waste circuit board copper powder is selectively removed by adopting a mode of combining chemical leaching and mechanical treatment, the problem of harm of the impurity metal in the waste circuit board copper powder to pyrometallurgical copper smelting is solved, and the recycling of metal resources is realized.
Description
Technical Field
The invention relates to a hydrometallurgy process in the field of nonferrous metallurgy, in particular to a hydrometallurgy method for selectively removing impurity metals in waste circuit board copper powder by adopting a mode of combining chemical leaching and mechanical treatment.
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 which adopts a mode of combining chemical leaching and mechanical treatment to treat the waste circuit board copper powder, has high removal rate of the impurity metals such as aluminum, iron, lead, tin and the like and has complete process flow.
In order to achieve the aim, the invention adopts the technical scheme that: leaching waste circuit board copper powder in a ball milling tank by using a sulfuric acid solution to selectively leach aluminum and iron in the waste circuit board copper powder; after drying the obtained leaching slag, separating lead and tin into fine particles by adopting a mechanical screening mode, and enriching copper into coarse particles; and finally, treating the coarse particles in a potential-controlled hydrochloric acid oxidation leaching manner, and deeply removing lead and tin in the coarse particles to further enrich the copper. The essence of the invention is that firstly sulfuric acid ball milling leaching is adopted to realize the removal of aluminum and iron, then mechanical screening is adopted to obtain coarse particles rich in copper and fine particles mainly containing lead sulfate and tin oxide, and finally potential-controlled hydrochloric acid is utilized to carry out oxidation leaching to deeply remove lead and tin in the coarse particles. 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 sulfuric acid ball milling leaching
Preparing a sulfuric acid solution with the molar concentration of 1.0-3.0 mol/L, adding waste circuit board copper powder according to the liquid-solid ratio (the ratio of the volume L of the solution to the weight Kg of solid) of 2-8: 1, adding the mixed slurry into a polytetrafluoroethylene ball milling tank, controlling the rotating speed of the ball mill to be 300-600 rpm, carrying out ball milling for 1-4 h, cooling to room temperature after the reaction is finished, filtering, carrying out solid-liquid separation by adopting a vacuum filtration mode, recovering aluminum and iron from a sulfuric acid leaching solution, and carrying out subsequent further treatment on sulfuric acid leaching residues. The main chemical reactions occurring during the sulfuric acid ball milling leaching process are as follows:
2Al + 3H2SO4 = Al2(SO4)3 + 3H2 (1)
Fe + H2SO4 = FeSO4 + H2 (2)
Pb + H2SO4 = PbSO4↓ + H2 (3)
Sn + H2SO4 = SnSO4 + H2 (4)
2SnSO4 + 2H2O = (SnOH)2SO4↓ + H2SO4 (5)
2 mechanical screening of leached residues
Adding the dried sulfuric acid leaching residue into a mechanical vibration screening machine for screening, and controlling the aperture of a screen mesh to be 150-380 DEG
And m, sieving for 10-50 min to obtain coarse particles rich in copper and fine particles mainly containing lead sulfate and tin oxide.
Coarse-particle potential-controlled hydrochloric acid oxidation deep deleading tin
Preparing a hydrochloric acid solution with the molar concentration of 1.0-4.0 mol/L, adding coarse particles according to the liquid-solid ratio (the ratio of the volume L of the solution to the weight Kg of solid) of 2-8: 1, controlling the reaction temperature to be 30-80 ℃, simultaneously adding hydrogen peroxide at the speed of 1.0-5.0 mL/min, continuing to react for 1-3 hours when the potential value of the solution is maintained at-100 mV, filtering while hot after the reaction is finished, realizing solid-liquid separation by adopting a vacuum filtration mode, recovering lead and tin from the hydrochloric acid leachate, and taking the hydrochloric acid leachate as a copper concentrate.
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. the method adopts a mode of combining chemical leaching and mechanical treatment to treat the waste circuit board copper powder, and simultaneously realizes effective removal of aluminum, iron, lead and tin in the waste circuit board copper powder; 2. the method comprises the steps of leaching in a ball milling tank by using a sulfuric acid solution to realize the high-efficiency removal of aluminum and iron in the waste circuit board copper powder, wherein the removal rates of the aluminum and the iron respectively reach more than 94.5 percent and 90.7 percent; 3. mechanically screening the leached slag to obtain coarse particles and fine particles, and enriching lead and tin in the fine particles, wherein the proportion of the lead and the tin is respectively over 86.1 percent and over 67.9 percent; 4. the coarse particles are treated by adopting a potential-controlled hydrochloric acid oxidation mode, and the removal rates of lead and tin respectively reach more than 94.1 percent and 97.7 percent; 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. Sulfuric acid, hydrochloric acid and hydrogen peroxide are all industrial grade reagents.
Preparing a sulfuric acid solution with the molar concentration of 2mol/L, adding waste circuit board copper powder according to the liquid-solid ratio of 5: 1, adding the mixed slurry into a polytetrafluoroethylene ball-milling tank, controlling the rotating speed of a ball mill to be 450rpm, carrying out ball-milling for 2 hours, cooling to room temperature after the reaction is finished, and filtering, wherein the removal rates of aluminum and iron respectively reach more than 94.5% and 90.7%. Adding the dried leaching residue into a mechanical vibration screening machine for screening, and controlling the aperture of a screen mesh to be 250
m, sieving for 30min, and enriching lead and tin into fine particles, wherein the proportion of the lead and the tin respectively reaches over 86.1 percent and over 67.9 percent; preparing molarityHydrochloric acid solution with the temperature of 3.0mol/L, adding coarse particles according to the ratio of 5: 1 of liquid-solid ratio (the ratio of the volume L of the solution to the weight Kg of solid), carrying out an experiment in a beaker, heating and stirring by using a constant-temperature magnetic stirring water bath kettle, controlling the reaction temperature at 70 ℃, simultaneously adding hydrogen peroxide at the speed of 1.0mL/min, continuing to react for 1h when the potential value of the solution is maintained at-48 mV, filtering while hot after the reaction is finished, and respectively achieving the removal rate of lead and tin in the coarse particles to be more than 94.1% and 97.7%.
Claims (1)
1. A method for removing impurity metals from waste circuit board copper powder through ball milling is characterized by comprising the following steps:
(1) sulfuric acid ball milling leaching
Preparing a sulfuric acid solution with the molar concentration of 1.0-3.0 mol/L, adding waste circuit board copper powder according to a liquid-solid ratio, namely the ratio of the volume L of the solution to the weight Kg of solid, of 2-8: 1, adding the mixed slurry into a polytetrafluoroethylene ball milling tank, controlling the rotating speed of the ball mill to be 300-600 rpm, carrying out ball milling for 1-4 h, cooling to room temperature after the reaction is finished, filtering, carrying out solid-liquid separation by adopting a vacuum filtration mode, recovering aluminum and iron from a sulfuric acid leaching solution, and further processing sulfuric acid leaching residues; the waste circuit board copper powder comprises the following components in percentage by mass: 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;
(2) mechanical screening of leached slag
Adding the dried sulfuric acid leaching residue into a mechanical vibration screening machine for screening, and controlling the aperture of a screen mesh to be 150-380 DEG
Screening for 10-50 min to obtain coarse particles rich in copper and fine particles mainly containing lead sulfate and tin oxide;
(3) coarse-particle potential-controlled hydrochloric acid oxidation deep deleading tin
Preparing a hydrochloric acid solution with the molar concentration of 1.0-4.0 mol/L, adding coarse particles according to a liquid-solid ratio, namely the ratio of the volume L of the dissolved liquid to the weight Kg of solid, of 2-8: 1, controlling the reaction temperature to be 30-80 ℃, simultaneously adding hydrogen peroxide at the speed of 1.0-5.0 mL/min, continuing to react for 1-3 hours when the potential value of the solution is maintained at-100 mV, filtering while hot after the reaction is finished, realizing solid-liquid separation by adopting a vacuum filtration mode, recovering lead and tin from the hydrochloric acid leaching solution, and taking the hydrochloric acid leaching residue as a copper concentrate.
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