The world is moving into a new era where energy is no longer produced on the basis of fossil fuels such as oil, coal and natural gas. The energy in the upcoming decades will be increasingly produced on the basis of wind and sun as well as nuclear power with more and more electric drives in vehicles, trains, ships and machinery in our households requiring a battery if used in areas that have no permanent connection to the grid. The metals and minerals required for electric motors are mainly copper for the winding, aluminium for the casing and iron-cobalt-nickel, neodym-iron-bor or samarium-cobalt for the permanent magnets. And the metals required for the batteries are mainly lithium, nickel, manganese, cobalt (NMC with high energy density) or lithium, iron, phosphate (LFP with lower energy density). And the demand of these elements will rapidly increase with...

Especially, elements like lithium, cobalt, neodym, samarium or other elements of the rare earth fraction appear in very low concentration in minerals and require an intense hydro metallurgical processing. This processing requires several steps of solids liquid separation steps with challenges such as extreme pH-values (<2 or >12), temperatures > 100 °C, intense wash of solids, low moisture, continuous operation, etc. Especially intense wash of solids quite often ends up in two or three steps of filtration with intermediate solids reslurry. However, this pushes CAPEX for filtration equipment to the high end and puts the realization of projects at risk.

Modern pressure drum filters such as the BOKELA BoHiBar Drum XL 18 or XL 26 are able to perform a three-stage counter current cake wash with a slurry that is fed to the filter with a temperature of up to 200 °C and solids with a d₅₀ of down to almost 1 micron...

The design of the filter with

- A high number of individual filter segments

- A quick drainage of the liquid into the piping system to the control head

- A sharp separation of the wash liquids in the control head

- An operation with back pressure on the filtrate separators

result in reaching the target figures with only one filter unit while other filter types like plate and frame filter presses require two filters with intermediate reslurry. Or the material of construction does not allow for temperatures in the range of 100-200 °C...