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Merrill-Crowe Circuit Design & EPCM

Zinc-precipitation recovery for silver-rich and high-tenor solutions — from 30 m³/h modular to 4,772 m³/h site-built.

Merrill-Crowe is the recovery technology of choice when ore is silver-dominant or when leach-solution grades are too high for economic carbon adsorption. KCA has designed Merrill-Crowe plants from 30 m³/h modular units (Aurex, Peru) to the 4,772 m³/h Hycroft site-built circuit — and the recently commissioned 1,200 m³/h Camino Rojo Merrill-Crowe for ORLA Mining is among the largest in North America.

30 m³/h (Aurex, Peru)
Smallest delivered
4,772 m³/h (Hycroft)
Largest delivered
1,200 m³/h (Camino Rojo, 2022)
Most recent major
Modular or Site-Built
Configuration

Clarification

Pre-clarification removes suspended solids that would otherwise interfere with zinc precipitation. KCA designs pressure-leaf clarifiers, deep-bed filters, or vacuum drum filters depending on solution character and throughput.

Vacuum Deaeration

Critical step — dissolved oxygen passivates zinc dust and kills recovery. KCA deaeration towers achieve <1 ppm O₂ at design flow, with packed-tower designs optimized for the specific solution density and viscosity.

Zinc Precipitation

Zinc-dust feeders and reaction mixers sized to gold + silver tenor. KCA also designs lead-nitrate addition systems for refractory silver solutions where additional activation is needed.

Precipitate Filtration

Plate-and-frame filter presses to dewater the zinc-gold-silver precipitate cake. Filter sizing matched to gold + silver tenor and operating schedule.

Smelting & Refining

Mercury retort (if needed for Hg-bearing concentrates), tilting-crucible smelting furnace, and matched off-gas scrubbing for SO₂ / NOₓ / particulate control. KCA Models 225T / 430T / 800T.

Reference Installations

Camino Rojo (Mexico) · Hycroft (Nevada) · Tambomayo (Peru) · Potosí (Bolivia) · Soledad Mountain (California) · Pinos Altos · El Cubo · San Antonio · multiple others.

Reference Projects

Where KCA has deployed this.

Related Capabilities

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