A process for making a carbonaceous material and a carbonous residue from scrap tires is disclosed. Tires are digested in an oil product. Steel and glass fibers are separated. A product enhancing additive comprising halogen based organic or inorganic compounds is added. The resulting carbonaceous material is then cured to create the final product. The produced carbonous residue is well suited for capture of mercury. The present invention has the benefits of providing a use for scrap tires that would otherwise require disposal in a landfill, and also produces a product useful for capturing a harmful element, thereby providing multiple environmental and economic benefits.