Solid-solid separation of carbon from a hardly soluble alkaline earth sulfate

A process for recycling carbon and a hardly soluble alkaline earth sulfate from a leaching residue, comprising the steps of:

• contacting in an alkaline earth metal contacting step a lithium battery material with an alkaline earth metal comprising material in a solvent yielding an alkaline earth metal contacted lithium battery material;
• leaching in a leaching step the alkaline earth metal contacted lithium battery material in sulfuric acid yielding a leaching solution and the leaching residue, wherein the leaching residue comprises carbon and the hardly soluble alkaline earth sulfate;
• separating in a solid-liquid separation step the leaching residue from the leaching solution;
• suspending in a suspension step the leaching residue in a solvent yielding a suspended leaching residue;
• contacting in a carrier contacting step the suspended leaching residue with a plurality of at least one type of a carrier body,
• wherein
• at least a part of the carbon comprised in the suspended leaching residue is agglomerated with the plurality of at least one type of a carrier body,
• yielding a suspension comprising
• carrier-body agglomerates comprising carbon, and
• non-agglomerates comprising the hardly soluble alkaline earth sulfate,
• or wherein
• at least a part of the hardly soluble alkaline earth sulfate comprised in the suspended leaching residue is agglomerated with the plurality of at least one type of a carrier body,
• yielding a suspension comprising
• carrier-body agglomerates comprising the hardly soluble alkaline earth sulfate, and
• non-agglomerates comprising carbon;
• and
• separating in a solid-solid separation step at least a part of the carrier-body agglomerates from the suspension.