A method and system for recovering gold from gold-containing dry films

Abstract

The application discloses a method for recovering gold from gold-containing dry film, which comprises the following steps: in the film stripping process after gold plating, introducing gold-containing film stripping tank liquor into a filtering separation device to separate solid gold-containing film residue and liquid gold-containing film stripping liquor; performing electrolysis treatment on the separated liquid gold-containing film stripping liquor to recover gold from the liquid gold-containing film stripping liquor; and performing incineration treatment on the separated solid gold-containing film residue to recover gold from the solid gold-containing film residue. The method can recover adsorbed gold in the dry film and related waste in the whole process, so that the gold resource can be maximally recovered, and the production cost and environmental pollution can be reduced.

Description

Technical Field

[0001] This invention relates to the field of gold recovery technology in electronic manufacturing, specifically to a method and system for recovering gold from gold-containing dry films. Background Technology

[0002] In the electronics manufacturing industry, gold electroplating is widely used in the manufacturing of printed circuit boards and semiconductor devices, with gold (Au) being a key precious metal. Traditional gold recovery technologies mainly focus on recovering gold from "explicit" gold-containing systems such as electroplating baths and rinsing water. However, during electroplating, gold can adhere to the photosensitive dry film through physical adsorption or chemical bonding, forming the phenomenon of "dry film adsorbed gold," which has long been neglected by the industry. For the gold-containing stripping solution and gold-containing film residue generated during the stripping process (i.e., peeling off the photosensitive dry film), existing processes lack systematic recovery technologies and procedures. These gold-containing stripping solutions and residues are usually disposed of directly as hazardous waste, increasing hazardous waste treatment costs and leading to a significant waste of gold resources. Currently, traditional gold recovery processes only cover a portion of the explicit gold-containing systems, failing to effectively recover gold from "dry film adsorbed gold" and its derivatives (such as film residue and stripping solution), resulting in incomplete recovery and high costs associated with precious metal loss. Therefore, there is an urgent need for a method that can achieve the maximum recovery of gold from dry film and related waste throughout the entire process. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method and system for gold recovery from gold-containing dry films, which addresses the shortcomings of incomplete gold resource recovery in the prior art. This method can recover adsorbed gold from dry films and related wastes throughout the entire process, thereby maximizing the recovery of gold resources and reducing production costs and environmental pollution.

[0004] To achieve the above objectives, according to one aspect of the present invention, a method for recovering gold from a gold-containing dry film is provided, comprising: In the stripping process after electroplating gold, the gold-containing stripping bath solution is introduced into a filtration and separation device to separate solid gold-containing film residue and liquid gold-containing stripping solution. The separated liquid gold-containing stripping solution is subjected to electrolytic treatment to recover gold from the liquid gold-containing stripping solution; The separated solid gold-containing film residue is incinerated to recover gold from the solid gold-containing film residue.

[0005] In the above scheme, the filtration and separation device includes a drum filter and a spiral pressure roller desqueezing device.

[0006] In the above scheme, the drum filter is set on the side of the film stripping tank. The gold-containing film stripping tank liquid is separated by the rotation of the drum. The separated solid gold-containing film residue is intercepted and forms a filter cake, which is then collected after being squeezed dry by the spiral pressure roller drying device.

[0007] In the above scheme, the separated liquid gold stripping solution is electrolyzed after the end of the usage cycle.

[0008] In the above scheme, the electrolytic treatment of the separated liquid gold-containing stripping solution specifically includes: The liquid gold stripping solution is finely filtered to remove solid particles. The filtered stripping solution is introduced into an electrolysis device and electrolyzed under stable voltage conditions until the gold concentration in the stripping solution is lower than a preset threshold.

[0009] In the above scheme, the filter medium used for fine filtration has a precision of 10μm or less.

[0010] In the above scheme, the stable voltage of electrolysis is 3V to 5V.

[0011] In the above scheme, the preset threshold is 0.5 ppm.

[0012] In the above scheme, before incineration, the solid gold-containing film residue obtained by separation is collected in a sealed container. After the collection amount reaches the set standard, it is incinerated.

[0013] According to another aspect of the present invention, a system for recovering gold using a gold-containing dry film is provided, comprising: The separation module is used in the stripping process after electroplating gold to introduce the gold-containing stripping bath solution into the filtration and separation device to separate the solid gold-containing film residue and the liquid gold-containing stripping solution. An electrolytic recovery module is used to electrolyze the separated liquid gold-containing stripping solution to recover gold from the liquid gold-containing stripping solution; The incineration and recovery module is used to incinerate the separated solid gold-containing film residue to recover gold from the solid gold-containing film residue.

[0014] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: (1) This invention provides a method for recovering gold from gold-containing dry film. This method can recover adsorbed gold from dry film and related waste throughout the entire process, so as to maximize the recovery of gold resources and reduce production costs and environmental pollution.

[0015] (2) This invention first clearly proposes the phenomenon of "gold adsorption by dry film" and systematically develops a recycling method for its entire waste logistics (dry film, stripping solution, and film residue), achieving a breakthrough from concept to process, and enabling gold recycling to cover previously neglected links; it includes "gold adsorption by dry film", gold in washing solution, gold in stripping solution and gold in film residue into the recycling scope, forming a closed-loop recycling. Compared with the traditional process that only recycles the visible system, this invention can increase the overall gold recovery by more than 40%, significantly reducing the waste of precious metals.

[0016] (3) This invention significantly reduces the amount of gold-containing waste liquid and waste discharged into the environment through efficient recycling, thereby reducing the potential pollution risk of precious metals to water bodies and soil, and meeting the requirements of clean production and sustainable development. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic flowchart of a method for recovering gold using a gold-containing dry film according to Embodiment 1 of the present invention.

[0018] Figure 2 This is a schematic diagram of the membrane stripping solution filtration and electrolysis process in Embodiment 1 of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0020] It should be understood that the sequence number of each step in the embodiment does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0021] Example 1 This application provides a method for recovering gold from gold-containing dry film, applicable to PCB production lines with thick electroplated gold layers and large gold adsorption capacity in the dry film. For a more detailed description of this method for recovering gold from gold-containing dry film, please refer to [link to relevant documentation]. Figure 1 ,include: S1, in the stripping process after electroplating gold, the gold-containing stripping bath solution is introduced into a filtration and separation device to separate solid gold-containing film residue and liquid gold-containing stripping solution.

[0022] Specifically, in this embodiment, in the MASK stripping line production process, a set of devices equipped with a precision roller filter (filtration accuracy 20μm) and a spiral pressure roller squeezing device is installed on the side of the stripping tank. The stripping tank and the roller are connected through a feeding trough. The tank liquid continuously enters the liquid cavity formed by the roller and the feeding trough. The roller rotates slowly at a constant speed under the drive of a drive motor. When the roller is immersed in the tank liquid, under the action of gravity, negative pressure, or pressure difference, the liquid components in the tank liquid (filtrate, liquid gold stripping solution) seep out through the pores of the filter medium in the roller and enter the set filtrate collection tank; while the tank The membrane sludge particles (solid components, including gold-containing solid membrane sludge) in the liquid are intercepted by the filter media on the surface of the drum, forming a uniform membrane sludge filter cake. As the drum continues to rotate, the membrane sludge filter cake will rotate out of the liquid chamber and enter the subsequent dewatering stage. The spray cleaning device will spray and clean the membrane sludge filter cake. After the part of the drum with the membrane sludge filter cake is rotated out of the liquid chamber, it enters the dewatering area. The rotating drum will automatically carry out the membrane sludge filter cake. The pressure roller of the spiral pressure roller squeezing device squeezes the membrane sludge filter cake to squeeze out the internal water. The solid gold-containing membrane sludge will be transported to the centralized collection container by the conveying device.

[0023] S2, the separated liquid gold stripping solution is electrolyzed to recover gold from the liquid gold stripping solution.

[0024] Specifically, in this embodiment, such as Figure 2 As shown, the separated liquid gold-containing stripping solution is collected in a filtrate collection tank. Once the filtrate collection tank reaches a certain level, the liquid gold-containing stripping solution is pumped back into the stripping tank for the stripping process. After the liquid gold-containing stripping solution completes its usage cycle, it is pumped into a recovery filtration device for secondary fine filtration (10μm filter bag) to remove solid particles. After filtration, the solution is transferred to the electrolysis tank, and the electrolysis device is turned on. Electrolysis is performed under a stable voltage (4V) until the gold concentration is ≤0.5ppm before discharge. The electrolyzed gold is deposited on the cathode plate and periodically stripped off.

[0025] S3, the separated solid gold-containing film residue is incinerated to recover gold from the solid gold-containing film residue.

[0026] Specifically, in this embodiment, when the solid gold-containing film residue in the collection container is collected, once the collection amount reaches a predetermined weight standard, it is incinerated for harmless treatment and gold recovery is completed simultaneously.

[0027] This embodiment achieves online real-time separation and offline centralized processing of liquid gold-containing stripping solution and solid gold-containing membrane slag, which is suitable for large-scale, continuous production. The total gold recovery rate in this embodiment (covering stripping solution electrolysis and membrane slag incineration refining) is significantly improved compared with the old process.

[0028] In summary, this embodiment provides a method for recovering gold from gold-containing dry films. This method can recover adsorbed gold from the dry film and related waste throughout the entire process, thereby maximizing the recovery of gold resources and reducing production costs and environmental pollution.

[0029] Example 2 This application provides a method for recovering gold from a gold-containing dry film, which is basically the same as the method in Example 1, except that: In this embodiment, the film stripping bath solution is not continuously filtered online; instead, it is processed as a batch every week or two. The operator pumps the waste film stripping solution directly from the stripping tank into the temporary storage tank of the integrated equipment. After secondary filtration, it is directly electrolyzed to recover gold; the electrolysis voltage is 3.5V.

[0030] Another aspect of this application provides a system for recovering gold using a gold-containing dry film, comprising: The separation module is used in the stripping process after electroplating gold to introduce the gold-containing stripping bath solution into the filtration and separation device to separate the solid gold-containing film residue and the liquid gold-containing stripping solution. An electrolytic recovery module is used to electrolyze the separated liquid gold stripping solution in order to recover gold from the liquid gold stripping solution; The incineration and recovery module is used to incinerate the separated solid gold-containing film residue in order to recover gold from the solid gold-containing film residue.

[0031] It should be noted that, depending on the implementation needs, the various steps described in this application can be broken down into more steps, or two or more steps or parts of the steps can be combined into new steps to achieve the purpose of this invention.

[0032] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for recovering gold from a gold-containing dry film, characterized in that, include: In the stripping process after electroplating gold, the gold-containing stripping bath solution is introduced into a filtration and separation device to separate solid gold-containing film residue and liquid gold-containing stripping solution. The separated liquid gold-containing stripping solution is subjected to electrolytic treatment to recover gold from the liquid gold-containing stripping solution; The separated solid gold-containing film residue is incinerated to recover gold from the solid gold-containing film residue.

2. The method for recovering gold from a gold-containing dry film according to claim 1, characterized in that, The filtration and separation device includes a drum filter and a spiral pressure roller desiccant.

3. The method for recovering gold from a gold-containing dry film according to claim 2, characterized in that, The drum filter is installed on the side of the film stripping tank. The gold-containing film stripping tank liquid is separated into liquid and solid by the rotation of the drum. The separated solid gold-containing film residue is intercepted and forms a filter cake, which is then collected after being squeezed dry by the spiral pressure roller drying device.

4. The method for recovering gold from a gold-containing dry film according to claim 1, characterized in that, The separated liquid gold stripping solution is then subjected to electrolytic treatment after the end of its service life.

5. The method for recovering gold from a gold-containing dry film according to claim 1, characterized in that, The electrolytic treatment of the separated liquid gold-containing stripping solution specifically includes: The liquid gold stripping solution is finely filtered to remove solid particles. The filtered stripping solution is introduced into an electrolysis device and electrolyzed under stable voltage conditions until the gold concentration in the stripping solution is lower than a preset threshold.

6. The method for recovering gold from a gold-containing dry film according to claim 5, characterized in that, The fine filtration uses a filter medium with a precision of 10μm or less.

7. The method for recovering gold from a gold-containing dry film according to claim 5, characterized in that, The stable voltage for electrolysis is 3V to 5V.

8. The method for recovering gold from a gold-containing dry film according to claim 5, characterized in that, The preset threshold is 0.5 ppm.

9. The method for recovering gold from a gold-containing dry film according to claim 1, characterized in that, Before incineration, the solid gold-containing film residue obtained by separation is collected in a sealed container. Once the collected amount reaches a set standard, it is incinerated.

10. A system for recovering gold from gold-containing dry films, characterized in that, include: The separation module is used in the stripping process after electroplating gold to introduce the gold-containing stripping bath solution into the filtration and separation device to separate the solid gold-containing film residue and the liquid gold-containing stripping solution. An electrolytic recovery module is used to electrolyze the separated liquid gold-containing stripping solution to recover gold from the liquid gold-containing stripping solution; The incineration and recovery module is used to incinerate the separated solid gold-containing film residue to recover gold from the solid gold-containing film residue.

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