Comprehensive recovery method for tin-stripping waste liquid

A recycling method and tin stripping technology, applied in the direction of improving process efficiency, can solve the problems of secondary pollution, excessive tin stripping waste liquid, insufficient recovery of components, low comprehensive recovery rate, etc., so as to achieve no secondary pollution and good practicality. Value and comprehensive benefits, the effect of high recovery rate

Active Publication Date: 2018-05-25
HOHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In view of some deficiencies in the above-mentioned prior art, the purpose of the present invention is to provide a comprehensive recovery method for tin stripping waste liquid, which mainly solves the low comprehensive recovery rate and complicated process of tin, copper and other substances in the recovery process of tin stripping waste liquid. , more secondary pollution and the problems that the components in the tin stripping waste liquid cannot be fully recovered

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  • Comprehensive recovery method for tin-stripping waste liquid

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Embodiment 1

[0024] Element

[0025] Treatment steps: 1) Pass the tin stripping waste liquid into the distillation device for vacuum distillation operation, the temperature is controlled at about 80°C, the pressure is kept at 0.03-0.04MPa, and the distillation condensate is collected as nitric acid; 2) The distillation residue The liquid is naturally cooled at room temperature. When the temperature reaches below 30°C, adjust the pH of the distilled residual liquid to about 1.5 with caustic soda, add 0.5‰ PAM for natural precipitation, filter and separate the solid substance, which is the tin compound, and obtain the tin removal solution. Tin compounds can be sold as coarse tin powder; 3) Measure the COD of the solution after tin removal, continue to adjust the pH of the solution after tin removal to 3-4 with caustic soda, then add hydrogen peroxide to the solution, and the dosage is 1.1 times the COD of the solution , at the same time add a little ferrous iron and stir for about 2...

Embodiment 2

[0027] A professional treatment enterprise of printed circuit board waste liquid in Jiangsu, the main components of its tin stripping waste liquid are nitric acid 10.2% (mass percentage), tin 85g / L, copper 2.3g / L, iron 3.7g / L, lead 25mg / L L. Treatment steps: 1) Directly use caustic soda to adjust the pH of the tin-removing waste liquid to about 1, stir and add 0.5‰ PAM for reaction, filter and separate the solid substance after natural precipitation, which is the tin compound, and obtain the tin removal solution. The tin compound can be Sold as coarse tin powder; 2) Measure the COD of the solution after tin removal, continue to adjust the pH of the filtrate to 3-4 with caustic soda, then add hydrogen peroxide to the solution, the dosage is 1.1 times the COD of the solution, and add a little ferrous iron at the same time 3) Extract the organic-free solution obtained after the reaction with Lix984, separate the extract and raffinate, back-extract the extract with sulfuric acid s...

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Abstract

The invention discloses a comprehensive recovery method for tin-stripping waste liquid. The method includes the following steps that (1) the tin-stripping waste liquid is subjected to reduced pressuredistillation so that nitric acid in the tin-stripping waste liquid can be recovered, a still residue is obtained, and tin powder is recovered from the still residue; or the pH value of the tin-stripping waste liquid is directly adjusted to recover the tin powder; (2) organic matter in a tin-removed solution is removed by means of oxidation with a Fenton reagent; (3) extraction is performed, and electrolysis or evaporation is conducted to extract copper; (4) iron and lead in the residue are removed; and (5) sodium nitrate is recovered through evaporation. Compared with the prior art, the method mainly solves the problems that the comprehensive recovery rate of the substances like tin and copper in the recovery process of the tin-stripping waste liquid is low, the technology is complicated,secondary pollution is serious, and all the components in the tin-stripping waste liquid cannot be fully recovered. By adoption of the method, various resources like the nitric acid, tin, copper andiron in the tin-stripping waste liquid can be effectively recovered step by step, the recovery rate is high, the technology is simple, secondary pollution is avoided, aero release in tin-stripping waste liquid treatment is realized, and the practical value and comprehensive benefits are good.

Description

technical field [0001] The invention relates to a comprehensive recovery method for tin stripping waste liquid, which belongs to the fields of environmental protection, resource regeneration and comprehensive utilization. Background technique [0002] Tin stripping waste liquid is one of the typical wastes in the PCB industry. There are two main sources of it: one is the tin stripping waste liquid produced in the printed circuit board stripping process, and the other is the wet treatment of waste circuit boards for components. The tin stripping waste liquid produced when the tin stripping is separated from the substrate, because some old circuit boards have a tin-lead alloy process in the production, so this kind of tin stripping waste liquid often contains lead. At present, the nitric acid type tin stripping solution has become the dominant type of tin stripping solution for circuit boards due to its advantages such as fast tin stripping speed and large tin stripping capaci...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00C22B15/00C22B25/06C23F1/46
CPCC22B7/006C22B15/0089C22B25/04C22B25/06C23F1/46Y02P10/20
Inventor 李继洲宋垠先
Owner HOHAI UNIV
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