The Alchemist's Lab: A Detailed Guide to Gold Recovery from IC Chips

Disclaimer: This article is for informational purposes only. The process of recovering gold from electronic scrap involves highly corrosive and dangerous chemicals. It should only be attempted by individuals with extensive knowledge of chemistry and a safe, controlled laboratory environment. The proper use of personal protective equipment (PPE) and adherence to safety protocols are non-negotiable.

Required Materials and Equipment 🧪

Chemicals:

• Nitric Acid (HNO3)

• Hydrochloric Acid (HCl)

• Urea (CO(NH2)2)

• Sodium Metabisulfite (Na2S2O5) or Oxalic Acid

• Butyl Diglyme – Optional, for further purification

Equipment:

• Heat-resistant container (e.g., a stainless-steel pan)

• Bunsen burner or gas torch

• Mortar and pestle

• Fine-mesh screen (e.g., a kitchen grease screen)

• Beakers

• Glass funnel

• Filter paper or coffee filters

• Crucible

• Separatory funnel

• High-temperature gas torch (for melting)

• Fume hood (mandatory)

• Personal Protective Equipment (PPE): Gloves, goggles, face shield, lab coat

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Step 1: Prepping the Chips & The Ashing Method 🔥

First, carefully separate the epoxy plastic packages from the fiber bottoms of your IC chips. Next, use the ashing method or pyrolysis by placing the epoxy parts in a stainless-steel pan and heating them. The heat will burn off all organic material, leaving only the metallic components behind. Once they are fully charred and cooled, you're ready for the next step.

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Step 2: Grinding and Sieving

Once the chips are cool, use a mortar and pestle to grind them into a fine powder. This is a crucial step as it increases the efficiency of the acid processing later on. After grinding, sieve the powder through a fine-mesh screen to separate any larger particles.

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Step 3: Nitric Acid Processing 🧪

Now, it's time to dissolve the base metals. Place the fine powder in a beaker and add Nitric Acid (HNO3). This acid will dissolve all base metals like copper and silver,
but will not affect the gold. When the fizzing stops, filter the solution, discard the acid, and thoroughly rinse the remaining solids with water. This is an essential step to prevent copper contamination.

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Step 4: Aqua Regia & The Gold Solution 💧

With the base metals removed, it's time to dissolve the gold. Prepare a fresh batch of Aqua Regia (HNO3 + 3HCl) and add it to your refined solids. This powerful mixture will dissolve the gold. It's absolutely mandatory to perform this step in a fume hood, as it releases highly toxic fumes.

Based on your discussion thread, some individuals use Butyl Diglyme at this stage for further purification. They take the solution in a separatory funnel, add Butyl Diglyme, and shake for five minutes. They then rinse it 2-3 times with HCl. This advanced method can significantly increase the purity of the gold.

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Step 5: Neutralization & Gold Precipitation ✨

After the gold has dissolved, you must neutralize the excess nitric acid by adding Urea (CO(NH2)2). This is a critical step before gold can be precipitated. Once the solution is neutralized, filter it and add a precipitant like Sodium Metabisulfite (Na2S2O5) or Oxalic Acid. The gold will then "drop" out of the solution as a fine powder.

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Step 6: Cleaning and Melting 🔥

Separate the gold powder and clean it thoroughly by boiling it in water and a little bit of Hydrochloric Acid (HCl). Once clean, the gold is ready for the final step. Place the gold powder in a crucible and use a high-temperature gas torch to melt it at 1064°C, turning the powder into a solid piece of gold.

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Common Problems and Solutions 🛠️

Why does the Aqua Regia turn green?

The green color indicates copper contamination in your solution. This usually happens when the initial Nitric Acid bath didn't dissolve all the copper. To avoid this, ensure that your initial nitric acid step is complete and the solution is thoroughly filtered before adding Aqua Regia.

Why is my yield so low?

A low yield might be since you only processed the epoxy plastic packages and not the fiber bottoms. While the fiber halves contain much less gold, their cumulative value adds to the total yield. For optimal results, process all parts of the chip.

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This guide provides a comprehensive step-by-step process for gold recovery. Remember, patience and safety are the most important components of this process.

If you want to see this process in action, you can watch my video here: A Detailed Guide to Gold Recovery from IC Chips