Mining & processing

Kolwezi Cobalt Electrowinning Tankhouse

Name: EST Africa
Address: 17 Refinery Road, Driehoek, Germiston, Gauteng, 1401, ZA
Telephone: +27 11 383 1900
Price range: $$$$

A tankhouse superstructure and crane gantry over cobalt electrowinning cells — the most chemically aggressive interior environment in African metals processing.

Industrial refinery interior with overhead crane gantry structure

Project data

Client: Katanga Mineral Refining
Location: Kolwezi, Lualaba, DRC
Year completed: 2025
Tonnage: 2 200 t
Environment: ISO 12944 C5-I sulphuric acid mist
Steel grade: S355J2+N
Coating: Vinyl ester over zinc-rich, 500 µm DFT
Crane: 2 × 25 t stripping machines
Corridor: 3 100 km via Kasumbalesa

The challenge

Electrowinning tankhouses run at 100 % relative humidity saturated with sulphuric acid aerosol. Standard C5-I epoxy systems in this service have been observed failing within seven years — well short of the asset life.

Our solution

We moved to a vinyl-ester topcoat over a zinc-rich primer at 500 µm total DFT, applied under controlled conditions with hold-point inspection at every coat. Crane gantry girders were detailed with sealed box sections and no upward-facing horizontal surfaces, so acid condensate cannot pool anywhere on the structure.

The outcome

The longest cross-border delivery in our portfolio — 3 100 km through two borders — landed complete, on sequence, with no consignment held longer than 48 hours at any checkpoint.