High Energy Hood (Solution for control of acid mist)
Chilean Patent N° 46,686-2010

This system captures the acid mist emissions at the source, evenly throughout the entire cell.

For this purpose, is used the available energy at the surface of the electrolyte (t °), plus the energy released in the explosion of the oxygen bubbles that forms the electrowinning process, and which are also the cause of the formation of the mist.

The system consists in a device with three chambers in it, joined by perforations, which generate the required pressure gradients. Then the acid mist is transported to a scrubber-condenser where it is retained in the form of sulfuric acid (98% retention efficiency), which is also reusable in the process.

Benefits

• It is the most efficient acid mist capture system in the world.
• Minimum fugitive emissions.
• Allows to increase current density (production increasing), above any other systems, keeping acid mist levels below the allowed ranges.

(With adequate maintenance, the system has achieved concentrations below 0.6 mg/m3 continuously for 7 consecutive months, with current densities reaching up to 426 amp/m2).

Low Energy Scrubbing Chamber (Solution for dust control in material transfers)
Patent Application N° 999-2013

Reduces dust emission in material transfers between conveyor belts or from chute to conveyor belt.

The Low Energy Scrubbing Chamber with scrubbing system by abatement or suppression has two main elements: the inertial chamber, designed to produce a control volume around the dust emission point, and the abatement/suppression system that allows depressurize the inertial chamber to reduce emissions and to scrubbe the extracted air from the chamber.

Benefits of the System

• Dust emissions are not affected by drafts.
• Low water/air consumption.
• Low energy consumption.
• Does not increase the humidity of the transported material.
• Easy maintenance. Without moving parts.

Cross Flow Ventilation System with Ejectors and Wall Scrubber (Solution for acid mist control)
Patent Application N° 2477-2015

• Ejector network: high velocity/low flow air jets that generate acid mist sweeping.
• Extraction system: Extracts contaminated air, with a larger area than other solutions, increasing the capture capacity.
• Scrubber module: Captures acidic aerosols with small drops of water. The collected pollutant is recycled back to the process.
• Secondary ventilation: Generates air renewals eliminating some of the emissions not collected by the absorbent wall.

Advantages and Features

• Recommended for small tankhouses. Effect of cross ventilation allows greater sweep efficiency.
• Does not interfere with the cathode harvesting operation.
• System requires less maintenance, achieving a more stable operation over time.
• Less implementation cost than a High Energy Hood based system.
• Lower operating cost since it does not require handling during harvest.
• Efficiency level inside the tankhouse is lower than the system with High Energy Hoods and has higher fugitive emissions.