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A kind of tin stripping water based on hydrochloric acid-tin salt system and the method for reclaiming tin from waste tin stripping water

A tin stripping and hydrochloric acid technology, which is 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: 2016-06-29
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 invention, the tin-clad layer of PCB or electronic components is stripped by traditional dipping or spraying method.

[0039] The waste tin stripping water obtained after tin stripping is regenerated in the following way: first, 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 used as an electrolyte and placed in an anion diaphragm electrolytic cell Diaphragm electrowinning in the cathode and anode compartments. After electrowinning, the cathode obtains tin, and the anode regenerates tin tetrachloride, and the regenerated tin tetrachloride solution can be reused as a raw material for preparing tin stri...

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 use the dipping method to strip the tin stripping water for 30 minutes on the purchased multiple tin-coated PCBs. After the tin stripping is completed, a bright stripped tin PCB and 9.82L of tin stripped liquid are obtained. Add hydrochloric acid to the solution after tin stripping to make the final concentration of free hydrochloric acid 170g / L. Take 2L of the tin-stripping liquid for diaphragm electrodeposition treatment. With the titanium plate as the cathode and the titanium plate as the anode, the current density is 500A / m 2 Electrodeposition was carried out under the conditions of 40°C temperature and 4cm distance between poles. Sampling and analyzing the concentration of tin ions in the cathode cha...

Embodiment 3

[0044] Get the anode solution 500mL obtained in above-mentioned embodiment 1, example 2 and dilute to 1L with water, add hydrogen peroxide, hydrochloric acid, ferric chloride, thiourea and citric acid therein, make its concentration be 12g / L, 100g / L respectively , 15g / L, 0.8g / L, 3g / L. Use the dipping method to strip the tin stripping water for 30 minutes on the purchased multiple tin-coated PCBs to obtain a bright PCB board and a tin stripping solution. The solution after tin stripping is subjected to diaphragm electrodeposition treatment. With iron plate as cathode and graphite as anode, the current density is 450A / m 2 Electrodeposition was carried out under the conditions of 45°C temperature and 4cm distance between poles. When the tin ion concentration in the cathode chamber is 8g / L, stop electrowinning. After cathode stripping, 42g of electrotin was obtained, and its purity was 95.8% through ICP-AES analysis. The concentration of tetravalent tin ions in the anode solut...

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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 the waste tin stripping water, belonging to the technical fields of comprehensive utilization of nonferrous 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. After the copper layer of the non-circuit part is etched and removed, the electrolytic tin layer must be removed with tin stripping water to make the copper circuit appear. [0003] Common tin stripping waters include fluoroborate-peroxide system, nitric acid system and nitric acid-alkylsul...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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