The comminution and concentrate circuits are already commissioned with operations underway.
The remainder of the demonstration plant is transitioning to operations with the aim of producing mixed hydroxide precipitate and cobalt sulphate.
The demonstration plant contains:
- A kiln for thermal decomposition of pyrite into pyrrhotite and elemental sulphur;
- An autoclave circuit for leaching pyrrhotite;
- An iron removal circuit;
- A MHP circuit;
- A refining circuit to produce cobalt sulphate; and
- Onsite production of oxygen for leach and nitrogen for the kiln.
Cobalt Blue has mined 2300t of ore for the trial from its Pyrite Hill deposit. A 60m long underground portal was developed to access the orebody.
During 2021 Cobalt Blue built and operated a smaller scale pilot plant.
That facility has been upgraded over the past six months to increase capacity and includes all processing unit operations to treat ore to produce MHP, which is typically 30% cobalt and 5% nickel.
The Pyrite Hill ore has been stage crushed, followed by dry milling in a roller mill to a top size of about 1mm.
That fine ore is being processed through the concentrator circuit, which is made up of rougher and cleaner gravity spirals, and a scavenger flotation cell. The target is to generate a minimum of 600t of concentrate from 3000t of ore.
The pyrite concentrate will be treated using Cobalt Blue's patented flowsheet to recover cobalt and elemental sulphur.
The demonstration plant program is expected to operate in aggregate for 20 weeks on a 24-7 basis.
The program will be split into campaigns to allow for analysis and optimisation of plant performance.
Samples of MHP and cobalt sulphate will be provided to prospective offtake parties.
Early supply of samples will help with qualification into the battery manufacturing chain ahead of future commercial operations at the Broken Hill Cobalt Plant.
Samples of cobalt sulphate will also be provided to the Australian Future Batteries Industry Cooperative Research Centre Precursor Pilot Plant, which opened in Perth on July 11.