Method for separating and recovering silver and palladium from silver-palladium alloy scrap

Abstract

The invention discloses a method for separating and recovering silver and palladium from silver-palladium alloy scrap. The comprises the following steps of dissolving and leaching high-silver low-palladium alloy scrap by using nitric acid; conducting selective palladium precipitation on the leachate by adding a first palladium precipitation agent, and filtering to obtain silver-rich filtrate and palladium-rich salt; preparing high-purity silver powder from the silver-rich filtrate by adopting a reduction method; and after palladium-rich salt oxidation acid leaching, adding a second palladium precipitation agent for further purification and recovery. By adopting the recovery method to recover palladium, the problem of entrainment loss of precious metal ions caused by a traditional chlorination precipitation method is optimized, the tedious step of repeatedly washing silver chloride precipitates to recover the precious metal ions is avoided, the recovery process of the palladium is greatly shortened, the recovery rate and purity of the palladium are remarkably improved, meanwhile, the influence of the palladium on recovery of the high-purity silver powder is avoided, the energy consumption can be effectively reduced, the difficulty in wastewater treatment is reduced, and the method is environment-friendly.

Description

Technical field [0001] The present invention relates to the field of precious metal recovery techniques, and more particularly to a method of separating silver, palladium from a silver palladium alloy waste. Background technique [0002] High-performance silver palladium alloy materials are widely used in modern industrial and high-tech industries, in particular, silver conductive materials, which are added palladium, can effectively control the migration of silver ions compared to sterling silver. Other advantages and applied to semiconductors and microelectronics industry. Due to the electronic waste, catalyst, catalyst, catalyst, catalyst, and waste, produced during development, production and use, have a number, harmful, potential value, high recovery difficulties, so efficient recycling These precious metals have important economic benefits. [0003] At present, the process of recovering silver palladium in the industrial is mainly nitric acid dissolved - hydrochloride-hydro...

AI Technical Summary

Problems solved by technology

However, for the nitric acid leaching solution of silver-palladium alloy waste, during the silver chloride precipitation process, because the fine silver chloride precipitates are easy to coat or entrain other metal ions, it is necessary to perform multiple cleaning and redissolving steps of silver chloride. In particular, it will cause the loss of precious metal ions due to dispersion, and produce a large amount of waste water, causing environmental pressure; and in the process of electrolytic recovery of silver, due to the influence of inclusion of precious metal ions, multiple castings and electrolysis of the anode plate are required, and silver electrolysis is not complete. The obtained anode slime still needs to further recover the precious metals in it, the process is cumbersome, the recovery time is long, and the equipment requirements are high