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Method for recycling tin removal waste liquor

A technology of tin stripping and waste liquid, applied in the field of regeneration and reuse of nitric acid type tin stripping waste liquid, can solve the problems of low recovery rate of nitric acid and other resources, low quality of regenerated tin stripping liquid, low recovery rate of free acid value, etc. To achieve the effect of easy mass production, good application effect and good recovery effect

Inactive Publication Date: 2013-12-11
深圳市世清环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, most of the existing recycling technologies for tin stripping waste liquid have some problems, such as the quality of regenerated tin stripping liquid is not high, there are many regeneration processes, the operation is complicated, the recovery rate of free acid value is low, the treatment cost is high, waste liquid or waste gas will be generated, etc.
[0014] Therefore, it is necessary to develop a simple, stable and reliable, economical and environmentally friendly recycling technology for tin stripping waste liquid, and then effectively solve the low recovery rate and environmental pollution of resources such as nitric acid in the tin stripping liquid, and provide better economic and environmental protection. Effective technical solutions are very necessary

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Add sodium oxalate to the tin stripping waste liquid containing 18% nitric acid, and complete the chemical precipitation reaction after uniform stirring. The tin content in the tin stripping waste liquid is 132 g / L, the copper content is 25 g / L, the sodium oxalate concentration is 0.6 mol / L, the reaction temperature is 25 ℃, and the reaction time is 30 min. After the precipitation reaction is completed, gravity sedimentation is performed. After separating the precipitation, 700 mL of the clear liquid is obtained, in which the tin content is 14.4 g / L, the copper content is 2.1 g / L, and the nitric acid content is 17.5%. 300 mL of the new tin stripping waste liquid is added to obtain the regenerated tin stripping liquid. Place the tin-clad circuit board in the regenerated tin stripping solution. It takes 15s to strip the tin. After the tin stripping, the surface of the circuit board is clean, the copper metal is bright in color, and the tin stripping effect is good.

[0042]...

Embodiment 2

[0046] Add oxalic acid, sodium oxalate and dimethyl oxalate (complex precipitation agent) to the tin stripping waste liquid containing 18% nitric acid, and complete the chemical precipitation reaction after uniform stirring. The tin content in the tin stripping waste liquid is 132 g / L, the copper content is 25 g / L, and the concentrations of oxalic acid, sodium oxalate and dimethyl oxalate are 0.25 mol / L, 0.20 mol / L, 0.20 mol / L, respectively , The reaction temperature is 25 ℃, and the reaction time is 30 min. Centrifugal separation is carried out after the precipitation reaction is completed. The separated precipitate contains 26.5% tin, 92% tin recovery, 5% copper recovery, 95% copper recovery. After ammonia leaching of the precipitated product, the copper content of the copper ammonia solution is 100 g. / L, 24 g of copper powder is obtained by electrolysis. After ammonia leaching, the solid phase product is dissolved in strong alkali to obtain 121 g of tin by electrolysis. The...

Embodiment 3

[0050] Add oxalic acid, sodium oxalate, dimethyl oxalate and polycarboxylic acid to the tin stripping waste liquid containing 18% nitric acid, and complete the chemical precipitation reaction after uniform stirring. The tin content in the tin stripping waste liquid is 132 g / L, the copper content is 25 g / L, and the concentrations of oxalic acid, sodium oxalate and dimethyl oxalate are 0.25 mol / L, 0.20 mol / L, 0.20 mol / L, respectively , The dosage of polycarboxylic acid is 1 g / L, the reaction temperature is 25℃, and the reaction time is 30 min. After the precipitation reaction is completed, it is separated by gravity sedimentation. The separated precipitate has a tin content of 26.1%, a tin recovery rate of 95%, a copper content of 5%, and a copper recovery rate of 95%. 700 mL of clear liquid after separation and precipitation, including tin content 9.4g / L, copper content 1.5g / L, and nitric acid content 20%. The separated clear liquid can restore the tin stripping function after ...

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Abstract

The invention provides a method suitable for recycling waste liquor in a tin removing procedure of a circuit board industry, and the method is suitable for the recycling of tin removal waste liquor which takes nitric acid as a main component and contains heavy metal compounds, such asnamely tin, copper, and the like. The method comprises the following steps of: treating heavy metals contained in the tin removal waste liquor by adopting a complexing precipitation method, and depositing metal ions contained in the tin removal waste liquor. According to the invention, after the tin removal waste liquor is subjected to solid-liquid separation, metal resources, such asnamely the tin, the copper, and the like, can be recovered from deposits; clear liquor and new tin removal liquor are similar in component and are recycled in the tin removing procedure after being appropriately regulated, so that the purpose of recycling of the tin removal waste liquor is realized. The method provided by the invention can realize the recycling of the tin removal waste liquor, can be used for efficiently recovering the metal resources contained in the waste liquor, has the advantages of simple process, small equipment investment, low energy consumption and no waste water and waste gas discharge in an operating process and realizes the clean production of the tin removing procedure.

Description

Technical field [0001] The present invention relates to the technical field of resource recycling in the chemical industry, especially the circuit board industry, and particularly relates to a method for recycling the tin stripping waste liquid generated in the tin stripping process in the production of printed circuit boards. The invention is preferably suitable for nitric acid type Regeneration and reuse of tin stripping waste liquid. Background technique [0002] Tin stripping is an indispensable step in the manufacturing process of printed circuit boards (PCBs). It is used to strip the tin plating that protects the copper substrate. The widely used tin stripping solution is nitric acid + ferric nitrate type, and its tin stripping mechanism is shown in the following formula: [0003] ; [0004] ; [0005] ; [0006] In the tin stripping solution, both nitric acid and ferric nitrate play the role of tin stripping. The nitric acid mainly strips the tin on the surface of the tin c...

Claims

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Application Information

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IPC IPC(8): C23F1/46C23F1/30
Inventor 王丹丹吴思国帅和平陈福明
Owner 深圳市世清环保科技有限公司
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