Centralized recovery treatment process for nitric acid type system tin stripping liquid

By removing copper, then iron, and finally aluminum in sequence, combined with the use of cationic coagulants and NaOH to adjust the pH, the problem of impurity accumulation and tin loss in nitric acid-based tin stripping solutions has been solved. This achieves efficient tin recovery and high-purity tin dioxide production, and is suitable for tin stripping solution treatment in printed circuit board production.

CN121250366APending Publication Date: 2026-01-02SHENZHEN JUNZE ENVIRONMENTAL PROTECTION CO LTD
0 Cites 2 Cited by

Patent Information

Application Number
CN202511816924.3
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-12-04
Publication Date
2026-01-02

AI Technical Summary

Technical Problem

In existing nitric acid-based tin stripping solution recovery processes, the tin loss rate is high, and the accumulation of impurities affects the purity of tin recovery and the utilization of regenerated solution. Furthermore, the residual impurities during high-temperature calcination result in low tin dioxide purity, posing risks of corrosion and toxicity.

Method used

The process involves removing copper first, then iron, and finally aluminum. The pH is adjusted using cationic coagulants and NaOH to generate different precipitates. Impurities are then separated by filtration and centrifugation, and finally, high-purity tin dioxide is obtained by calcination.

Benefits of technology

It achieves an impurity removal rate of over 99%, a tin recovery rate of over 99%, and a tin dioxide purity of 99.5%, making it suitable for large-scale centralized processing, reducing reagent consumption and operational complexity, and meeting the requirements of green manufacturing.

✦ Generated by Eureka AI based on patent content.
Patent Text Reader

Abstract

The invention discloses a nitric acid type system tin stripping liquid centralized recovery treatment process which comprises the following steps: firstly, adding a cationic coagulant into a nitric acid type tin stripping waste liquid, filtering through a 5-micron filter membrane, discharging into a reaction kettle, and adding a H2O2 solution with the concentration of 5-10%; the pH is adjusted to 2.0-2.5, and copper is removed under the condition of 40-50 DEG C; when the pH value is increased from 2.5 to 3.0-3.5, iron is removed; adjusting the pH value to 13.0-13.5, heating to remove aluminum, and separating to obtain a filtrate containing Na2SnO3; adjusting the pH value of the filtrate to 6.0-6.5, heating to 70-75 DEG C for reaction, and then carrying out gradient cooling to room temperature to generate Sn (OH) 4 precipitate; and centrifugally separating the mixed solution to obtain a tin-containing solid and a tin stripping regenerated solution, and firing the tin-containing solid to obtain a tin dioxide solid. Compared with a traditional process, copper is removed firstly, then iron is removed, aluminum is finally removed, and directional removal is achieved through the difference of precipitation conditions.
Need to check novelty before this filing date? Find Prior Art