KEY PROCESS ATTRIBUTES: The selected process route avoids the disadvantages of conventional hot leaching and flotation and increases recoveries of the components of the raw salt. It can efficiently handle the polymineralic ore type found at Ohmgebirge by separating out the easily soluble chloride minerals (KCl and NaCl) from insoluble material and sulphate minerals at the cold leach stage. As noted in the scoping study, unwanted dissolved salt components in the resultant brine can be removed by precipitation of calcium carbonate and/or magnesium hydroxide with soda ash and/or caustic soda when added in the brine purification step prior to evaporation-crystallisation.

The precipitates are freely removed by sedimentation and filtration. Other key attributes identified during initial testing include: Bleed streams can be either monetized as other products or handled in the backfill. The chosen process, proven historically, maximizes the KCl recovery in similar ore bodies.

That a simple process route optimises the number of employees. The chosen route requires a lower demand for steam in heating process. The selected process consumes less energy and other auxiliary materials.

Over the various unit operations, the predicted recoveries were identified, and the results are in the range quoted in the scoping study. To clearly show the overall recovery from the ore, including the volumes of the waste streams to be backfilled, pilot scale testing is planned during 2023. Preliminary mass and energy balances will be included in pilot scale test work to inform equipment sizing and estimating for the PFS planned for completion during 2023.