Oxide products formed from calcined carbonate powder for use as biocide, chemical detoxifier and catalyst support products. A process and apparatus for manufacture of biocide products from caustic calcined carbonate powder, from carbonates such as magnesite, dolomite, or hydromagnesite, is described. The method of manufacture is based on the production of high surface area oxide particles using an indirectly heated counterflow reactor. The desirable properties of the biocide are a broad spectrum activity against viruses, bacteria, fungi and insects when applied as powder, granules or slurry to agricultural crops, food, masks or wipes through established application methodologies. The slurry is generally a feedstock for specific application, for example, a spray, or dried to a powder to form powdered products or granules, or mixed with oil to form an emulsion, or processed into a foam or fog. In another application, the powder product may be directly applied.
