How to extract precious metals such as gold from e-waste?
Gold is a natural product that exists in a free state in nature and cannot be artificially synthesized. According to the different sources and different contents after refining, it is divided into raw gold and cooked gold. Raw gold, also known as natural gold, barren gold, and raw gold, is the object of cooked gold. It is mined from mines or river bottom alluvial layers without melting and refining.
Nowadays, as the update rate of home appliances such as mobile phones and computers is getting faster and faster, many old home appliances are discarded casually. Experts say that these discarded e-wastes still have good use value. For example, some old mobile phones, computers and other parts can be picked out of gold-containing components to extract gold.
In 1 ton of electronic boards, 130 kilograms of copper, 20 kilograms of tin, and 0.45 kilograms of gold can be separated. "E-waste" has become an industry that hides huge profits.
Sources of e-waste:
(1) Gold-containing electronic components, video recorders, record players, measuring instruments, analyzers, computers and other instruments and some contacts, leads and circuit boards also contain gold.
(2) All kinds of gold-containing alloys, the content of gold in the alloys is very high. There are also many low-gold alloys that are more easily forgotten after use for the gold in them, and are only recycled as general metals.
(3) The gold content of various types of waste gold plating solutions varies greatly.
(4) Jewelry waste, anode slime, batteries, solder alloys, dental alloys, gold-plated devices and all devices involving the use of gold, such as chemical, electronics, medicine, electroplating and jewelry, contain gold.
The gold content in e-waste is much higher than that of the original ore, generally hundreds of times more. The recovery from it is much lower than the extraction cost from the original ore, and the economic benefit is very obvious. The grade of electronic waste waste generally ranges from 800-2000 grams per ton, that is, 0.8-2 grams of gold can be extracted per kilogram of waste.
Extraction process of precious metals such as e-waste gold:
Chips, north-south bridges, memory chips, integrated circuits, and plastic-encapsulated field effects that cannot be returned after dismantling are all components that contain high amounts of gold and silver in the components that are in line with unified treatment, and can be baked with ozone (ozone can completely destroy the components formed by combustion). Harmful flue gas), the roasting slag uses a solvent carrier, leaching copper, lead tin, hydrochloric acid medium to leaching gold, platinum and palladium, and extracting gold, platinum and palladium. For chip capacitors containing high silver and palladium, silver and palladium are independently extracted by acid method. For gold-plated circuit boards and plug-ins, it is recommended to use cyanide-free environmental protection gold stripping agent to quickly strip and extract gold.
For silver- and palladium-containing acoustic surfaces, metal-packaged triodes, and integrated circuits, use a special pin-cutting machine to cut off the metal shell and punch out the chip, and then extract valuable metals according to the chip and integrated circuit scheme. After crushing, metal aluminum is directly smelted. For Zener diodes, some varactor diodes, other glass-sealed components, and plastic-sealed luminous tubes, valuable metals are extracted after being crushed. Electrolytic copper is produced, palladium-containing circuit boards (double-sided circuit boards basically contain palladium, and palladium is used as a copper-plated substrate and contained in the conducting holes used as wires), and then palladium is leached with acid, and then palladium is extracted and extracted. There are many equipments in the whole refining process, which will not be described in detail here.
The extraction of precious metal gold such as electronic waste circuit boards can not only obtain economic benefits, but also an effective method for the rational treatment of current electronic waste. As a professional electronic waste recycling equipment manufacturer, SUNY GROUP has rich experience and technology in precious metal extraction. If you need it, please feel free to contact us.
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