Process for the manufacture of a composite material (M) comprising a stage (E) according to which a dispersion (D) comprising : (a) at least one polymer, (b) at least one lamellar compound, and (c) at least one dispersing liquid, is dried by atomization. Composite material (M') comprising (a') at least one polymer, (b') at least one lamellar compound, and (d') at least 0.02% by weight of at least one surface-active agent with respect to the weight of (a') in the dry state; composed of particles having a weight-average diameter D50 of less than or equal to 200 .mu.m. Method for processing this composite material.