The Hydrometallurgy Division (HMD) is a dynamic group within Mintek consisting of 43 professionals and technical staff. The division develops and tests hydrometallurgical flow sheets for the recovery and refining of metals from ores and concentrates. The principal areas of expertise are leaching, precipitation, cementation, ion-exchange, solvent extraction, electro-winning, and process simulations.


Facilities and scale of operation
The facilities group manages and controls the divisional facilities. HMD has facilities to undertake projects from basic flowsheet design through to laboratory testwork, piloting, and full-scale plant commissioning. The service includes process design, and optimisation of process conditions and economics based on computer simulation and experimental work. Personnel include chemists and engineers who work together in close collaboration throughout a project, and assist the engineering contractor with the final design and feasibility studies.

A range of laboratory and pilot-plant equipment include:

  • Ion Exchange Facilities
  • Solvent Extraction Facilities
  • Electro-winning Facilities
  • Leaching and precipitation includes the following equipment:
    • Advanced leach facility consisting of semi-automated mini-plant for determination of leaching kinetics and environmental parameters.
    • HMD has built up batch autoclave facilities for pressure leaching and precipitation test work. Equipment is available for the leaching of sulphide ores, laterite ores, alloys and mattes in sulphate media, together with hematite and jarosite precipitation.
    • Small-scale batch autoclaves (Ti-lined): Internal parts are manufactured from grade 2 titanium. These vessels are suitable for leaching and precipitation work in sulphate media up to 240ºC and 45 bar.
    • Medium-scale batch autoclave (SS 316 L): 10 l stainless steel autoclave (4-6 l working volume), suitable for leaching work in sulphate media up to 150ºC and 20 bar.
    • Large-scale batch autoclave (glass-lined): 40 l glass-lined Phaudler autoclave (20-30 l working volume). Suitable for leaches in sulphate media at up to 90ºC and 6 bar.
    • Air agitated pachuca tanks (3500 litre) for bulk leaching of slurries
    • Multi-purpose, stirred-tank cascade for batch or continuous leaching and precipitation.
    • Mechanically agitated, rubber lined tanks with volumes from 100 to 2000 litres for leaching test work.

Piloting is undertaken either in Mintek’s well-equipped pilot bays or on site at the client’s facility. Pilot campaigns have been carried out extensively both in southern Africa and internationally.