The process for agglomerating and passivating the pulverulent used material and/or the pulverulent fines resulting from the production of organohalosilanes, comprises the mixing of this used material and/or fines with a binder chosen from aluminum silicates and the production of a solid agglomerated product by compression in a press, such as a roll type briquette machine. The invention also relates to the agglomerated product thus obtained and to its use in the recovery of certain metals, such as silicon and copper.