Process for recovering precious metals from e-waste
Electronic waste is becoming more and more common in our daily life. For electronic waste, we can recover precious metals from it through relevant technical equipment. These precious metals have high reuse value. So what is the process of recycling precious metals from electronic waste?
Types of precious metals
Gold (Au), silver (Ag), platinum (Pt), osmium (Os), iridium (Tr), ruthenium (Ru), rhodium (Rh), palladium (Pd). There are eight metals in total, which are expensive and scarce in resources.
Waste and scraps containing precious metals
1. Waste electrical and electronic products, such as waste cell phone boards, cell phone chips, cables, battery contacts, cell phone sim cards; waste computer boards, CPUs, memory sticks, plugs; waste water containing gold or palladium from circuit board factories; jewelry factories waste; VCD boards, some electronic components on TV boards, etc. Various gold-plated pieces. Such as aviation plugs, gold-plated plug-ins on various electrical appliances, gold-plated electronic components, electronic feet, gold-plated handicrafts, etc. Various silver-containing wastes: photo-engraving wastewater, waste X-ray films, silver contacts, silver-containing ceramic capacitors, etc.
2. Processing trade enterprises: electronic component waste, circuit contact waste, waste water and waste mud of industrial electroplating plants (plating precious metals).
Recycling process
The basic process of precious metal recovery from electronic waste can be divided into two stages: pretreatment and subsequent treatment. Pretreatment refers to mechanical treatment methods; subsequent treatment includes pyrometallurgy, hydrometallurgy and biological methods.
1. Pretreatment
Pretreatment mainly refers to mechanical treatment, which is a means of sorting according to the differences in physical properties between materials, including density, conductivity, magnetism, surface characteristics, etc., including dismantling, crushing, sorting and other processing processes. Mechanical treatment can fully enrich valuable substances in electronic waste, reducing the difficulty of subsequent treatment. Compared with subsequent treatment, it has less pollution and lower cost, but cannot obtain precious metals with higher purity.
2. Post-processing
After subsequent treatment of electronic waste, precious metals with higher purity can be obtained, but it is easy to cause secondary pollution. Subsequent processing includes pyrometallurgy, hydrometallurgy and biological methods, etc.
Pyrometallurgy: The basic principle of pyrometallurgy is to use a metallurgical furnace to heat and strip non-metallic substances at high temperature, so that precious metals are melted into other metal smelting materials or molten salts. separate again. Non-metallic substances are mainly printed circuit board materials, etc. Generally, scum is separated and removed, while precious metals and other metals flow out in an alloy state, and then refined or electrolytically treated. Pyrometallurgy mainly includes incineration melting process, high temperature oxidation melting process, scum technology, electric arc furnace sintering process, etc.
The method has the characteristics of simple process and high recovery rate. It can process all forms of electronic waste. The main precious metals recovered are Au, Ag, Pd and so on. However, it is easy to produce secondary pollution, such as a large amount of harmful gases emitted by incineration, and solid waste generated by scum.
Hydrometallurgy: Its basic principle is to use the characteristics of crushed precious metal particles that can be leached under acidic or alkaline conditions, and separate them from electronic waste through solvent extraction, precipitation, replacement, ion exchange, electrolysis and other processes in the leaching solution. and recovered from the liquid phase.
This method can obtain high-grade and high-recovery precious metals such as Au and Ag. The recovery effect of non-ferrous metals such as Cu and Zn is also very good, and the processing cost is low.
SUNY GROUP is a professional waste e-waste recycling solution provider. With its rich experience and perfect technical equipment, it has solved the problem of e-waste recycling for many customers, from e-waste sorting and dismantling recycling to e-waste crushing and sorting, and then It has obvious advantages when it comes to precious metal refining and extraction. If you have any questions or needs, please feel free to contact us at any time.
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