Dissolve gold from computer scrap using aqua regia (nitric acid and hydrochloric acid in a 1:3 ratio), then precipitate with sodium metabisulfite for recovery. Melt purified gold powder with borax to form ingots.
- Preparation and Safety
- Prioritize safety: Wear gloves, goggles, and protective clothing. Ensure a well-ventilated area or use a fume hood.
- Gather necessary chemicals: 30% vinegar, 3% hydrogen peroxide, table salt, hydrochloric acid (HCl), nitric acid (HNO3), and sodium metabisulfite.
- Collect essential tools: Glass containers, plastic buckets, coffee filters, precision scale, and pH meter.
- Disassembling and Sorting
- Disassemble electronics to remove CPUs, RAM chips, motherboards, and PCI cards. Focus on parts with visible gold, like gold-plated fingers and connectors.
- Use a magnet to separate gold-plated steel parts, as steel requires a different recovery process.
- Chemical Processing for Gold Recovery
- Soak circuit boards and components in a mixture of 2:1 hydrochloric acid and 3% hydrogen peroxide to dissolve metals and separate gold. Stir daily for a week.
- For gold flakes recovery, use a solution of hydrogen peroxide and muratic acid to dissolve the adhesive on computer parts, then process with sodium bisulfate for gold precipitation.
- Employ aqua regia (a mixture of nitric acid and hydrochloric acid in a 1:3 ratio) for dissolving gold from high-grade components like CPU pins. Neutralize the solution post-reaction with sodium bicarbonate.
- Gold Precipitation and Purification
- After dissolving gold into the solution, add sodium metabisulfite to precipitate gold from the solution. Gold will form as a brown powder at the bottom.
- Filter the solution to collect gold powder. Rinse the gold powder with distilled water to remove residual acids.
- Melt the gold powder with borax to purify and form a gold ingot. Borax reduces the melting point of gold and separates impurities.
- Waste Treatment and Environmental Considerations
- Neutralize acidic solutions with a base like sodium bicarbonate before disposal to minimize environmental impact.
- Follow local regulations for the disposal of chemical waste to prevent environmental contamination.
- Refining and Selling the Gold
- Refine the gold as needed to increase purity. This may involve repeating the melting process with borax or using other refining techniques.
- Weigh and document the refined gold for sale. Gold buyers typically require documentation of purity and weight.
Source: Eightify
