Page 33 - Bullion World Volume 4 Issue 9 September 2024

Bullion World | Volume 4 | Issue 9 | September 2024

Commercial Silver Jewelry and Solar Panel Refining Using Vacuum Metallurgy
To develop a vacuum metallurgical recycling process for both jewelry and solar scrap, significant modifications to
the electromagnetic field parameters and algorithms were necessary. Traditional flat induction coils were found to
be unsuitable due to the high thermal conductivity of silver scrap and the need for multiple crystallization steps with
impurity removal.

Algorithm Development and Simulation
These requirements led to the development of new algorithms for the induction system. Mathematical simulation
models were created to predict the shape of the molten metal, compression ratio, internal heat source, process
control algorithms, solidification direction, and velocity. By solving the system of differential electromagnetic,
thermal, and hydrodynamic equations, a series of curves was generated that describe the conditions for levitational
crystallization. The algorithms that control the sustainable operation of the electromagnetic coils are based on
the relationships between system resistivity and voltage. The crystallization diagrams were designed to ensure
solidification at a single point, concentrating impurities in a smaller area. For solar panel scrap, the crystallization
process is designed to recover silver. In both silver and silicon solidification, the process should be terminated at the
top of the ingot to create a specific area for impurity removal.

Hermetically Sealed Crucibles: Minimal metal loss
Parameter Single load Continuous (less than 0.3%) is achieved using hermetically sealed
Electromagnetic Electromagnetic crucibles.
system system Ultrasound Enhancement: Applying ultrasound at 1
Load capacity 300 kg per hour 24 kg per hour MHz increases silver strength by 40%.

Impurity Removal: All precious metal impurities,
Ingot size 150 x 600 mm 150 x 300 mm except gold, can be effectively removed.

Inverter power 2 kW 80 kW Product Range: The technology produces high-purity
copper, silicon, and silver.
Electrical 0,3 0,35 Process Acceleration: Creating multiple heating
efficiency zones (5 zones, 1 kW each) speeds up the process.
Frequency 450-500 450-500 Movement Speed: The heating zone moves at a rate
of 0.5-1 mm/min.
range
Maximum Purity: The process can achieve a
maximum purity of up to 99.999%.

Conclusion
Commercial Application Benefits:
• Minimal Metal Losses: Direct metal losses are reduced to 0.3%.
• Large-Scale Capacity: The crucible-free technology enables high-throughput processing.
• Reduced Carbon Footprint: The process has a lower environmental impact.
• Faster Scalability: The technology can be easily scaled up for increased production.
• No Companion Metal Loss: Copper and silicon are not lost during the process.
• High Automation: All processes are integrated within a single furnace, minimizing manual intervention.

Note: PhD thesis Dr. Ashot Navasardian

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