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Method for recycling tin from waste tin-stripping solution based on tin-stripping solution of hydrochloric acid-tin salt system

A technology for stripping tin and hydrochloric acid, applied in the field of comprehensive utilization of non-ferrous metal resources and environmental protection, can solve the problems of low metal recovery rate, large consumption of reagents, heavy gas pollution, etc., to reduce dissolution, reduce copper content, and realize recycling. Effect

Active Publication Date: 2014-04-23
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Generally speaking, there are still two major problems in the tin stripping process and the treatment of tin stripping waste liquid in the current tin stripping water mainly based on nitric acid or nitric acid-alkylsulfonic acid: (1) The tin stripping process mainly uses nitric acid to dissolve tin, Copper is dominant, leading to NO in the current tin stripping water stripping process x Heavy gas pollution, large amount of sludge, high amount of residual acid, and high cost; (2) The current processes for treating waste tin stripping water by precipitation, electrolysis, and distillation have large consumption of reagents, low metal recovery, and waste water serious problems

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] The components and contents of the tin stripping water of the present invention are as follows: tin tetrachloride 80~230g / L; hydrochloric acid 70~220g / L; ferric chloride 10~30g / L; stabilizer 0.5~2.5g / L; accelerator 5~30g / L; brightener 2~5g / L, solvent is water.

[0038] In the present invention, the tin-clad layer of PCB or electronic components is stripped of tin by the traditional dipping or spraying method.

[0039] The waste tin stripping water obtained after the completion of tin stripping is regenerated in the following way: firstly, the acidity of the waste tin stripping water is adjusted by adding water or hydrochloric acid, and then the obtained waste tin stripping water is divided into an anion diaphragm electrolytic cell as an electrolyte Diaphragm electrowinning is carried out in the cathode and anode chambers. After the electrowinning is finished, the cathode obtains electric tin, and the anode regenerates tin tetrachloride. The regenerated tin tetrachloride sol...

Embodiment 2

[0042] Prepare 10L of tin stripping water based on hydrochloric acid-tin salt system, the components and contents are as follows: tin tetrachloride 110g / L; hydrochloric acid 150g / L; ferric chloride 20g / L; thiourea 1.5g / L; Hydrogen peroxide 20g / L; sodium citrate 3g / L. Then, the tin stripping water was immersed in the tin-coated PCB for 30 minutes. After the tin stripping is completed, a bright stripping PCB and 9.82L of the tin stripping liquid are obtained. Hydrochloric acid is added to the solution after tin stripping to make the final free hydrochloric acid concentration 170g / L. Take 2L of this tin stripped liquid for diaphragm electrowinning. With titanium plate as cathode and titanium plate as anode, the current density is 500A / m 2 , The temperature is 40℃, and the distance between different poles is 4cm. Sampling and analyzing the concentration of tin ions in the cathode compartment and Fe in the anode compartment every 30 minutes 3+ Concentration when Fe in the anode c...

Embodiment 3

[0044] Dilute 500 mL of the anode solution obtained in the above Example 1 and Example 2 to 1 L with water, and add hydrogen peroxide, hydrochloric acid, ferric chloride, thiourea, and citric acid to make the concentration 12g / L and 100g / L respectively , 15g / L, 0.8g / L, 3g / L. The tin stripping water was immersed in the tin-clad PCBs purchased for 30 minutes to strip the tin layer to obtain a bright PCB board and the tin stripping liquid. The tin stripped liquid is subjected to diaphragm electrowinning treatment. With iron plate as cathode and graphite as anode, the current density is 450A / m 2 , The temperature is 45℃, and the distance between different poles is 4cm. When the tin ion concentration in the cathode chamber is 8g / L, stop the electrowinning. After the cathode was stripped, 42 g of electro-tin was obtained, and its purity was 95.8% by ICP-AES analysis. The anode solution was analyzed, in which the tetravalent tin ion concentration was 51g / L and the trivalent iron io...

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Abstract

The invention discloses a method for efficiently recycling tin from a waste tin-stripping solution based on a tin-stripping solution of a hydrochloric acid-tin salt system. According to the tin-stripping solution, the components and the contents are as follows: 110-230g / L of tin tetrachloride, 70-220g / L of hydrochloric acid, 10-30g / L of iron chloride, 0.5-2.5g / L of a stabilizing agent, 5-30g / L of an accelerant and 2-5g / L of a brightener. The waste tin-stripping solution obtained by tin stripping is subjected to diaphragm electrodeposition treatment by using a cathode room and an anode room of an anion diaphragm electrolytic cell to recycle tin, the tin tetrachloride and ferric trichloride. According to the method for treating the waste tin-stripping solution, not only can the tin be effectively recycled from the waste tin-stripping solution, but also the tin tetrachloride and ferric trichloride can be regenerated and returned to prepare the waste tin-stripping solution to use; the problems of resource wastes, serious environment pollution and the like of a traditional waste tin-stripping solution treatment method are completely avoided.

Description

Technical field [0001] The invention relates to a tin stripping water based on a hydrochloric acid-tin salt system and a method for efficiently recovering tin from waste tin stripping water, belonging to the technical field of comprehensive utilization of non-ferrous metal resources and environmental protection. In particular, it relates to a formula of tin stripping water and a method for efficiently recovering tin from waste tin stripping water. Background technique [0002] In the manufacturing process of general printed circuit boards and electronic components, it is often necessary to electroplate tin on the surface of the copper layer as a protective layer for alkaline etching. When the copper layer of the non-circuit part is etched and removed, the tin plating layer must be removed with tin stripping water to make the copper circuit appear. [0003] Common tin stripping water includes fluoroborate-peroxide system, nitric acid system and nitric acid-alkylsulfonic acid system...

Claims

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Application Information

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IPC IPC(8): C23F1/44C23F1/46C25C1/14
Inventor 杨建广李焌源雷杰杨声海何静唐朝波陈永明
Owner CENT SOUTH UNIV
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