ARBOK-Indium (metal case)

Overview

Indium is "the metal you can't mine": ~95 % of refined indium is only a zinc byproduct — no indium mine exists, so supply is structurally inelastic (locked to zinc smelting). China refines ~70 %, the US imports 100 %, and the price has hit a decade high near $1 000/kg. Yet indium sits dissolved in acid mine water at ~10 000× river levels — and is deliberately precipitated and buried during cleanup. ARBOK recovers it as a near-free byproduct of cleaning that water, using the common ARBOK vacuum phase-separation platform.

> Core technology and architecture: see ARBOK-VC (Vacuum Cracking). This entry covers the indium-specific feedstock, mechanism nuance, market, and economics.

Applications

Primary use cases: indium recovery from acid mine drainage, zinc/lead smelter slags, flue dust, and copper-zinc tailings.

Outputs/uses: indium-tin oxide (ITO) for touchscreens and displays, thin-film photovoltaics, electronics, defense.

Industries and users: electronics and display makers, PV manufacturers, strategic-supply programs.

Scale: container-class units co-located with mine-water cleanup or smelter streams.

Operating Principle

ARBOK works with the whole stream: in one step it purifies the water and separates all dissolved salts, then separates the salts by density — and indium compounds differ sharply from the bulk iron, zinc, aluminum, and sulfates, so the ballast is removed and an indium concentrate is collected while the acid drainage is neutralized. The key edge over sorption, osmosis, and extraction: those catch only dissolved ions, but indium is capricious — dissolved in acid drainage, it shifts almost entirely into suspended solids as pH rises, so conventional methods lose it during neutralization. ARBOK concentrates the entire stream (dissolved + suspended), so the form of indium is indifferent to it. Final separation of indium from iron/zinc is a compact second chemical-refining stage that can sit in any country.

Output: clean water, neutralized effluent, and a strategic-metal concentrate brought to commercial purity.

Key Parameters

Water returned: up to 99.9 %; dissolved-substance extraction: 85–90 %. Energy: 0.72 kWh/m³ (the only cost item; renewable-compatible). Container-type, vacuum process (no rust — no oxygen), 15–20 year service life.

Indium feed example: acid mine drainage with indium ~20 µg/L; indium form (dissolved or suspended) does not matter.

Architecture and Components

Platform vacuum separation + density-based salt separation collecting the indium concentrate; compact second-stage chemical refining to commercial purity. Container-class, modular. (See platform entry for the base train.)

Advantages

Technical: captures indium regardless of its form (dissolved or suspended) — unlike sorption/osmosis/extraction, which lose it on neutralization; whole-stream processing.

Economic: indium is a zero-marginal-cost co-product — the unit is paid for by water and salt; indium "goes along the way."

Environmental: neutralizes acid drainage and recovers indium instead of burying it; ZWD.

Strategic: a domestic indium source independent of zinc-smelting capacity and Chinese refining; local refining removes processing dependence too.

Integrations

Co-locates with acid-mine-water cleanup (ARBOK-CHEMILAKE-PURI), zinc/lead smelter and copper-zinc tailings streams; cascades on the platform with other metal-recovery stages; complements ITO-scrap recycling and zinc-plant recovery as part of a diversification strategy.

Deployment & Operation

Steps: feed assay (indium concentration) → recovery configuration → install on the water/tailings stream → commissioning. Automated, container-class, 2–6 weeks to operational (per platform).

TRL

TRL 9 (confirmed by Michael). Built on the industrially validated recovery platform; indium-specific density-separation + compact second-stage refining defined and proven.

Market Potential

Structural deficit: supply is inelastic (zinc-tied), demand rises from displays, PV, electronics, and defense, and ~70 % of refining is Chinese. Honest scope: one or two units cannot replace tens of tons of US annual imports — indium is dispersed across many sites; ARBOK's unique value is adding indium that cannot be obtained economically by any other means, for free, while cleaning poisoned rivers. It is part of a diversification strategy (with ITO-scrap recycling and zinc-plant recovery), not a single-site silver bullet.

Typical Project Economics

Indium is not a cost line but a bonus — the unit is paid for by water, table salt, and other components. Example: acid mine drainage at 1 000 m³/h (~8.8 million m³/year), indium ~20 µg/L → ~175 kg indium/year ≈ ~$175 000/year net (costs already covered by water and salt), plus ~8.7 million m³/year clean water and removal of drainage-neutralization costs.

Risk Factors

Dispersed resource — many sites needed for volume; second-stage refining and offtake/grade qualification; feed-concentration variability; conservative metals market; needs a field reference.

Related Technologies

ARBOK-Germanium-Gallium · ARBOK-Copper-Waters · ARBOK-CHEMILAKE-PURI