CN1614046A - Extraction of gold from PCB by catalyst oxidation - Google Patents
Extraction of gold from PCB by catalyst oxidation Download PDFInfo
- Publication number
- CN1614046A CN1614046A CNA2004100672984A CN200410067298A CN1614046A CN 1614046 A CN1614046 A CN 1614046A CN A2004100672984 A CNA2004100672984 A CN A2004100672984A CN 200410067298 A CN200410067298 A CN 200410067298A CN 1614046 A CN1614046 A CN 1614046A
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- China
- Prior art keywords
- circuit board
- printed circuit
- gold
- catalyst
- catalytic oxidation
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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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- 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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- Manufacture And Refinement Of Metals (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention was involved in extracting gold by oxidizing circuit board. The process contained the following steps: a) The circuit board was orphyrized. b) The pulverizing circuit board and water solution of catalyst were mixed in the high-pressure autoclave with the stirrer. The ratio of circuit board and water solution of catalyst was 1 to 1-20. The catalyst contained 0.01-5mol/L nitric compound with more than bivalent nitrogen. c) The circuit board was oxidized by catalyst until the reaction was over completely .The reaction condition contained lower than 1.0 pH value, 1-100 pressure atmosphere, 30-180deg.C reaction temperature and 1-6h reaction time. d) The reactant was filtered and gold was extracted by the normal method from washing residue. The extraction ratio of gold was higher than that by normal method and the cost was low. Comprehensive utilization of various metals and innocent treatment of electron refuse was realized.
Description
Technical Field
The invention relates to a method for extracting metal from electronic waste, in particular to a method for extracting gold from a printed circuit board by catalytic oxidation.
Background
The printed circuit board contains lead, arsenic, cadmium, chromium, fluorine, bromine and other pollutants, and serious environmental pollution is caused by an irregular treatment and disposal method. And because the electronic waste contains precious metals, the economic value and the environmental protection significance of recycling the waste electronic waste are great. In fact, 130 kg of copper, 0.45 kg of gold, 20 kg of tin, palladium, tantalum, niobium and the like can be separated from 1 ton of electronic boards (mobile phones and computers), the gold value separated only is thousands of dollars, and electronic waste shells, keyboards and mice contain copper and plastics, which are all precious materials. Therefore, the development of a harmless recycling process has profound significance for eliminating electronic pollution and improving the resource reutilization rate.
In the prior art, mechanical sorting of printed circuit boards is used to separate organic and inorganic substances, and the metal mixture is extracted by conventional smelting methods. The traditional gold extraction method comprises smelting, an electrolytic method, aqua regia oxidation, a chlorination method, a wet gold extraction process and the like, the processes do not consider the characteristic of complex metal mixtures of electronic wastes, the re-extraction process of gold and other metals is complex, oxidants of nitric acid, aqua regia, chlorine and the like are not recovered, the treatment cost is high, the gold extraction cost of the electrolytic method developed at home and abroad is also high, private enterprises in China only extract gold by using a concentrated sulfuric acid leaching method, other metals are discharged outside, and the pollution of heavy metal ions and toxic plastics is very serious.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: provides a method for extracting gold by catalytic oxidation of a printed circuit board, which aims to solve the defects of the prior art.
In order to solve the technical problems, the invention adopts the technical scheme that: a catalytic oxidation gold extraction method for a printed circuit board comprises the following steps:
a. crushing the printed circuit board;
b. uniformly mixing the crushed printed circuit board and an aqueous solution of a catalyst in an autoclave containing a stirrer, wherein the weight ratio of the crushed printed circuit board to the aqueous solution of the catalyst is 1: 1-20, and the catalyst is a bivalent or higher compound containing 0.01-5mol/L of nitrogen; adjusting the pH value of the solution to be less than 1.0 by using inorganic acid, controlling the pressure in the high-pressure kettle to be 1-100 atmospheric pressures, and catalytically oxidizing the printed circuit board under the conditions of the temperature of 30-180 ℃ and the reaction time of 1-6 hours until the printed circuit board is completely reacted;
c. filtering the reacted mixture, washing the filter residue and extracting gold by a conventional method.
In the step a, the printed circuit board is crushed to the granularity of less than 1mm, the inorganic acid used in the step b is sulfuric acid or hydrochloric acid, and the catalyst can be recycled.
The compound with more than two valences of nitrogen is one or more of sodium nitrate, potassium nitrate, nitrite, nitric oxide and nitrogen dioxide.
The printed circuit board includes various types of circuit boards used for computers, televisions, mobile phones, game machines, electronic cards, large-scale equipment and the like.
The autoclave is filled with oxygen or air.
And (c) extracting various metals such as copper, nickel, palladium and the like from the filtrate obtained in the step c by using a conventional method, recycling the liquid left after the metal extraction into the step b, absorbing the tail gas generated in the step b by using an absorption tower if the tail gas is generated, and recycling the tail gas in the step b, wherein a reaction kettle used in the subsequent conventional cyanogen slag leaching gold extraction method is required to be resistant to oxidation and acid.
The invention has the beneficial effects that: on the premise that air or oxygen is used as an oxidant and a catalyst can be recycled, the treatment cost is low, the high extraction rate of gold is realized, various metals can be comprehensively utilized, the harmlessness, the reduction and the resource of electronic garbage are realized, and the method has greater significance at present when nonferrous metal resources are in shortage and the price is high.
Drawings
FIG. 1 Process flow diagram of the present invention
The workingprinciple of the invention is as follows:
the printed circuit board contains lead, arsenic, cadmium, chromium, fluorine, bromine and other pollutants, and also contains precious metals (gold, copper, tin, nickel, palladium and the like), the electronic waste shell, the keyboard and the mouse contain plastics, the metals and the plastics are tightly combined together, the complete separation of the metals and the plastics is difficult to realize by a mechanical method, and the mixture of the metals is difficult to obtain a higher separation effect by a traditional method, so that the metal which is easy to be oxidized is oxidized into ions by a catalytic oxidation method and is completely separated from the gold and the plastics, the gold is exposed, and the gold extraction by cyanidation is easy, so that a harmless resource recycling process is developed, and the method has profound significance for eliminating electronic pollution and improving the resource recycling rate.
Compounds with more than divalent nitrogen such as sodium nitrate, potassium nitrate, ammonium nitrate, sodium nitrite and the like have certain oxidizability, can oxidize metals in the printed circuit board into metal ions, and the catalytic oxidation reaction is as follows:
the newly generated nitric acid and nitrous acid can react with metal, so that the metal in the catalytic oxidation circuit board is converted into metal ions under the condition of the existence of air, gold is dissociated from clinker and the metal, and the gold is extracted by using a common cyanidation method.
Detailed Description
The present invention will be described in further detail with reference to examples, and reference is made to fig. 1.
Example 1
Adding a printed circuit board containing gold and NH with the concentration of 5mol/L into a reaction kettle4NO3SolutionMixing the two solutions at a weight ratio of 1: 1, stirring, and adjusting pH with sulfuric acidAnd (2) less than 1.0, pressing air into the reaction kettle by using a high-pressure pump, enabling the pressure to reach 100 atmospheric pressure, heating the reactant to 30 ℃, reacting for 6 hours, filtering to obtain filter residue after the printed circuit board is completely oxidized, neutralizing the filter residue by using lime, extracting gold by using a common cyanidation method at normal temperature, and determining that the leaching rate of the gold is up to 93% according to national standard.
Example 2
Adding a printed circuit board containing gold and NaNO with the concentration of 2.5mol/L into a reaction kettle2The solution and the solution with the weight ratio of 1: 2.5 are evenly stirred, hydrochloric acid is used for adjusting the pH value of the solution to be less than 1.0, air is pressed into a reaction kettle by a high-pressure pump, the pressure reaches 50 atm, reactants are heated to 120 ℃ and react for 4 hours. When the printed circuit board is completely oxidized, filtering to obtain filter residue, neutralizing the filter residue with lime, extracting gold at normal temperature by using a common cyanidation method, and determining according to national standards that the gold leaching rate is up to 95%.
Example 3
Adding a printed circuit board containing gold and a sodium nitrate solution with the concentration of 0.01mol/L into a reaction kettle, wherein the weight ratio of the printed circuit board containing gold to the sodium nitrate solution is 1: 9, uniformly stirring, adjusting the pH value of the solution to be less than 1.0 by using sulfuric acid, introducing air into the reaction kettle by using a high-pressure pump, heating reactants to 180 ℃ under normal pressure, and reacting for 1 hour. When the printed circuit board is completely oxidized, filtering to obtain filter residue, neutralizing the filter residue with lime, extracting gold at normal temperature by using a common cyanidation method, and determining according to national standards that the gold leaching rate is up to 99%.
Example 4
Adding a printed circuit board containing gold and a sodium nitrate solution with the concentration of 0.01mol/L into a reaction kettle, wherein the weight ratio of the printed circuit board containing gold to the sodium nitrate solution is 1: 20, uniformly stirring, adjusting the pH value of the solution to be less than 1.0 by using sulfuric acid, introducing air into the reaction kettle by using a high-pressure pump, heating reactants to 90 ℃ under normal pressure, and reacting for 5 hours. When the printed circuit board is completely oxidized, filtering to obtain filter residue, neutralizing the filter residue with lime, extracting gold at normal temperature by using a common cyanidation method, and determining according to national standards that the gold leaching rate is up to 99%.
Claims (7)
1. A catalytic oxidation gold extraction method for a printed circuit board is characterized by comprising the following steps: the method comprises the following steps:
a. crushing the printed circuit board;
b. uniformly mixing the crushed printed circuit board and an aqueous solution of a catalyst in an autoclave containing a stirrer, wherein the weight ratio of the crushed printed circuit board to the aqueous solution of the catalyst is 1: 1-20, and the catalyst is a bivalent or higher compound containing 0.01-5mol/L of nitrogen; adjusting the pH value of the solution to be less than 1.0 by using inorganic acid, controlling the pressure in the high-pressure kettle to be 1-100 atmospheric pressures, and catalytically oxidizing the printed circuit board under the conditions of the temperature of 30-180 ℃ and the reaction time of 1-6 hours until the printed circuit board is completely reacted;
c. filtering the reacted mixture, washing the filter residue and extracting gold by a conventional method.
2. The catalytic oxidation gold extraction method for the printed circuit board according to claim 1, characterized in that: the inorganic acid used in step b is sulfuric acid or hydrochloric acid.
3. The catalytic oxidation gold extraction method for the printed circuit board according to claim 1, characterized in that: in the step a, the printed circuit board is crushed to the granularity of less than 1 mm.
4. The catalytic oxidation gold extraction method for the printed circuit board according to claim 1, characterized in that: the compound with more than two valences of nitrogen is one or more of sodium nitrate, potassium nitrate, nitrite, nitric oxide and nitrogen dioxide.
5. The method for extracting gold by catalytic oxidation of the printed circuit board according to claim 1 or 2, characterized in that: the printed circuit board includes various types of circuit boards used for computers, televisions, mobile phones, game machines, electronic cards, large-scale equipment and the like.
6. The method for extracting gold by catalytic oxidation of the printed circuit board according to claim 1 or 4, wherein the method comprises the following steps: the catalyst can be recycled.
7. The catalytic oxidation gold extraction method for the printed circuit board according to claim 1, characterized in that: the autoclave is filled with oxygen or air.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2004100672984A CN1614046A (en) | 2004-10-20 | 2004-10-20 | Extraction of gold from PCB by catalyst oxidation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2004100672984A CN1614046A (en) | 2004-10-20 | 2004-10-20 | Extraction of gold from PCB by catalyst oxidation |
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| Publication Number | Publication Date |
|---|---|
| CN1614046A true CN1614046A (en) | 2005-05-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2004100672984A Pending CN1614046A (en) | 2004-10-20 | 2004-10-20 | Extraction of gold from PCB by catalyst oxidation |
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| Country | Link |
|---|---|
| CN (1) | CN1614046A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100406591C (en) * | 2006-10-31 | 2008-07-30 | 东华大学 | Method for extracting metal copper from electronical wastes |
| CN100447264C (en) * | 2007-04-13 | 2008-12-31 | 浙江理工大学 | Method for recovering gold from waste of gold plating procedure |
| CN102560138A (en) * | 2012-01-11 | 2012-07-11 | 森松(江苏)海油工程装备有限公司 | Pretreatment method of refractory gold ore |
| CN104263939A (en) * | 2014-09-09 | 2015-01-07 | 中国电器科学研究院有限公司 | Method for recovering rare/inert metals from bottom electroplating copper/nickel material |
-
2004
- 2004-10-20 CN CNA2004100672984A patent/CN1614046A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100406591C (en) * | 2006-10-31 | 2008-07-30 | 东华大学 | Method for extracting metal copper from electronical wastes |
| CN100447264C (en) * | 2007-04-13 | 2008-12-31 | 浙江理工大学 | Method for recovering gold from waste of gold plating procedure |
| CN102560138A (en) * | 2012-01-11 | 2012-07-11 | 森松(江苏)海油工程装备有限公司 | Pretreatment method of refractory gold ore |
| CN104263939A (en) * | 2014-09-09 | 2015-01-07 | 中国电器科学研究院有限公司 | Method for recovering rare/inert metals from bottom electroplating copper/nickel material |
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