Method for preparing high-purity silver nitrate from silver-containing waste

The described method for recycling silver from low-silver-content waste materials uses a combination of wet reduction, acid washing, fire refining, and ion exchange/chelating resin treatment to achieve high-purity silver nitrate, overcoming previous inefficiencies and safety issues.

CN119706915APending Publication Date: 2025-03-28JINCHUAN GROUP CO LTD +1
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Patent Information

Application Number
CN202411631031.7
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2024-11-15
Publication Date
2025-03-28

AI Technical Summary

Technical Problem

Current methods for recycling silver from silver-containing waste materials with silver content below 65% are inefficient, environmentally harmful, unsafe, and produce silver of low purity, necessitating a new approach to enhance silver recovery and purity.

Method used

A method involving wet reduction, acid washing, fire refining, electrolytic purification, and ion exchange/complexing resin treatment to produce high-purity silver nitrate from silver-containing waste, including steps like pH adjustment with sodium hydroxide, reduction, acid washing, melting with boron and sodium carbonate, electrolysis, and final purification using ion exchange and chelating resins.

Benefits of technology

The method achieves a silver nitrate purity of 99.8% and a production rate of 85% or higher, effectively addressing the inefficiencies and safety concerns of previous methods.

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Abstract

The invention relates to the technical field of industrial waste treatment and silver nitrate preparation, in particular to a method for preparing high-purity silver nitrate from silver-containing waste. The method comprises the following steps: reducing the silver-containing waste by adopting a liquid phase reduction method, pickling to remove impurities, putting the silver-containing waste into a medium-frequency induction furnace, performing high-temperature smelting and ingot casting, performing electrolytic purification to obtain crude silver powder, and performing smelting and ingot casting on the crude silver powder to obtain a raw material national standard No.1 silver ingot for preparing silver nitrate; the method comprises the following steps: putting a national standard No.1 silver ingot and a nitric acid solution into a reaction kettle according to a certain proportion for dissolving silver, carrying out adsorption and impurity removal on a dissolved solution through ion exchange resin, carrying out adsorption and impurity removal on a primary filtrate through chelating type adsorption resin, and carrying out centrifugation, evaporative crystallization, drying and other processes on a secondary filtrate to obtain the high-purity silver nitrate. The method is easy to implement, the recovery rate of the silver-containing waste materials is high, the high-purity silver nitrate product can reach the premium-grade pure standard, and the technological process is environmentally friendly.
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