System Overview

At-a-glance

Batch size: ~1 kg dry SiO₂-dominant feed → ~200 g silicon learning target.
Process chain: Molten oxide electrolysis (Fe→Si→Al staging) → vacuum refining → directional solidification.
Operating temperatures: 1600–1700 °C in the MOE cell; 1600–1900 °C during vacuum refining; 1450–1550 °C for casting.
Power input: 120 V AC service with a ≥1.8 kW inverter/UPS inline to ride through sag events and isolate controls.
Atmosphere management: Argon backfill loop with reclaim, oxygen evolution venting, and cold-trapped exhaust.
Footprint: Bench-top stack, approximately 0.8 m × 0.6 m × 1.2 m for the complete module set.

System architecture

The v0.1 build organizes the hardware into eight cooperating modules. Work through them in order to maintain clear interfaces.

Feed prep & autofeed – Hopper, auger, dryer (150–250 °C), and screening (≤250 µm) with an optional jaw crusher for raw rock.
MOE cell (melter + electrolyzer) – Insulated hot zone with ZrO₂/Al₂O₃ liners, refractory metal electrodes, and staged potentials for selective reduction.
Phase separation – Weir and sump geometry that parks iron in a deep pocket, skims slag, and directs silicon into an isolated collection pocket.
Vacuum refining pot – Dedicated vessel rated for 1600–1900 °C at ≤10 Pa with cold traps to capture SiO and phosphorous species.
Ingot casting – Directional solidification station using Si₃N₄-coated crucibles and a controlled cool-down plate.
Gas & vacuum skid – Rotary vane pump, optional dry scroll, argon buffer, dryer, filter stack, and oxygen vent/capture plumbing.
Controls & sensing – PLC or industrial micro, pyrometry, LIBS/OES for spectral feedback, residual gas analysis, and interlocks.
Power & energy – 120 V line conditioner or portable power station feeding heaters and controls with proper bonding and protection.

Operating envelope

Parameter	Baseline target
MOE hot-zone temperature	1625 °C nominal, 1600–1700 °C acceptable
Vacuum refining	1700–1800 °C, ≤10 Pa, 30–90 min hold
Casting	1450–1550 °C pour with 1–5 K/min directional cool
Current density (Fe stage)	0.2–0.4 A cm^-2, tuned via OES feedback
Atmosphere	Argon backfill 50–150 mbar above ambient, O₂ vented safely
Leak rate (argon test)	<50 sccm at 50 mbar over ambient

Parameter

Baseline target

MOE hot-zone temperature

1625 °C nominal, 1600–1700 °C acceptable

Vacuum refining

1700–1800 °C, ≤10 Pa, 30–90 min hold

Casting

1450–1550 °C pour with 1–5 K/min directional cool

Current density (Fe stage)

0.2–0.4 A cm^-2, tuned via OES feedback

Atmosphere

Argon backfill 50–150 mbar above ambient, O₂ vented safely

Leak rate (argon test)

<50 sccm at 50 mbar over ambient

Utilities and support equipment

Electrical: 120 V, 15–20 A circuit with GFCI protection, bonded grounds, and separated clean power for controls.
Cooling: Water loop for cold traps and any induction coil jackets; ensure flow monitoring before high-temperature work.
Instrumentation: Dual two-color pyrometers, LIBS head for feed characterization, OES aimed at the melt, and RGA on the refining foreline.
Gas handling: Argon reclaim loop with buffer tank, dryer, and filtration; oxygen vent line routed to a safe exhaust or capture bottle.

Workflow context

The overview sets the stage for the detailed chapters that follow. Continue to Materials & Components for the subsystem bill of materials before you start fabricating the frame.