Abstract: A process produces foam bodies having various properties and containing cellulose-containing materials broken up and/or partially broken up and/or not broken up, and additives, if need be. The cellulose-containing starting materials are first processed further for forming a moist pulp and subsequently subjected to a heat treatment by microwave radiation. The properties of the foam bodies so produced are predetermined by admixing certain substances intensifying the formation of gas in the pulp, increasing the adhesive bond between the particles in the pulp, or which completely or partially convert into a gas either under the influence of heat or of moisture, thus supporting the foaming. Furthermore, other residual and waste materials can be added during the production process, which may be materials of a silicate nature as well, preferably with the objective of reusing such materials in a useful way and of predetermining at the same time certain product properties of the foam bodies.