CONTEXT

Talc (Si₄Mg₃O₁₀(OH)₂) is a natural material, largely used in industry (cosmetic, pharmaceutical applications, tires,...) but composition and purity degree depend on the extraction zone and cannot be controlled (content in Fe, Al, F and traces of Mn, Ti, Cr, Ca, Ni, Na and/or K). Furthermore particle size is limited by the use of mechanical grinding  means.