Notes on Smelting Catalytic Converters

Introduction to Catalytic Converters

• Purpose: Recover precious metals (platinum, palladium, rhodium)
• Structure: Ceramic honeycomb matrix impregnated with precious metals
• Function: Acts as a catalyst to burn unburnt fuel from exhaust

Smelting Process Overview

1. Screening Material
   • Screen down to 16 or 20 mesh
2. Initial Materials for Smelting
   • 50 g anhydrous borax
   • 50 g soda ash
   • 25 g silica sand
   • 25 g bismuth oxide (collector metal)
   • Cooking flour (acts as carbon)

Chemical Reactions

• Carbon + Bismuth Oxide -> Pulls oxygen off Bismuth, forming CO2
• Bismuth reduced to metal, alloys with precious metals
• Result: Formation of bismuth-platinum alloy

First Attempt Results

• Resulting bismuth button: 21 g (close to expected 22 g)

Cupellation Process

• Heating button in a cupel at 1,900-2,000°F
• Bismuth oxidizes and is absorbed by the cupel, leaving precious metals behind
• Struggled with recovery: only 0.33 g recovered

Experiment with Pyrite

• New method using 50 g catalytic converter with 50 g pyrite
• Added 100 g of borax for better fluxing
• Expected recovery: 99% platinum, 97% rhodium

Collector Metals

• Iron and nickel: Good collectors for platinum group metals (PGMs)
• Iron sulfide enables collection at lower temperatures
• Initial tests with iron pyrite yielded good separation
• Next plan: Add 10 g copper for better collection

Further Refinements

• Smelting with copper intended to help recover PGMs
• 50 g of anhydrous borax, 50 g soda ash, and 25 g silica sand added
• Observations on slag and mat behavior

Results from Copper Test

• Resulting mat did not cooperate but slag appeared glassy
• Potential issues: insufficient soda ash or large copper pieces
• Experimenting next with 10-20 g silver as a new collector

Final Test Observations

• Crushing mat and re-melting to increase surface area
• Using iron nails to help reduce silver back to metal
• Final results: recovered all 20 g silver with good collection of PGMs

Conclusion and Future Steps

• Assaying samples for platinum, palladium, and rhodium
• Planning to scale up operations based on findings
• Encouragement to subscribe for part two of the process
• Potential support options: Patreon or YouTube super thanks

---

Key Terms

• PGMs (Platinum Group Metals): Platinum, Palladium, Rhodium
• Cupellation: Process of refining precious metals
• Mat: Layer of metallic composition after smelting