Abstract: Rubber particles having textile and/or metallic inclusions are treated by first placing the particles on a support surface and then pressing the particles against the support surface in a direction transverse to the support surface with a surface of a press body exerting a pressure of in excess of 10 kg/cm.sup.2 without contacting the surfaces with each other. Both of the surfaces are nonsmooth. In accordance with the invention the support surface and the press body are relatively displaced in a direction generally parallel to the support surface to subject the particles to shear.

Abstract: Comminuted salvaged rubber is heated to the reclaiming temperature in a two-stage process such that part of the overall heat required is introduced by microwave heating and the remainder by convectional heating. Material preheated during the first stage is transferred to the second stage in such a way that the relative position of all the particles is maintained with as little change as possible. Since the temperature profile of microwave heating shows a maximum in the interior and a minimum at the periphery, whereas that of convectional heating is just the reverse, the temperature distribution within the material can be evened out to a great extent by combining these two different methods of heating. Since it is no longer necessary in this case to heat the material to such an extent convectionally, it is possible to avoid caking and the formation of deposits, and thus to considerably improve the quality of the reclaimed rubber.

Abstract: Comminuted salvaged rubber is heated to the reclaiming temperature in a two-stage process such that part of the overall heat required is introduced by microwave heating and the remainder by convectional heating. Material preheated during the first stage is transferred to the second stage in such a way that the relative position of all the particles is maintained with as little change as possible. Since the temperature profile of microwave heating shows a maximum in the interior and a minimum at the periphery, whereas that of convectional heating is just the reverse, the temperature distribution within the material can be evened out to a great extent by combining these two different methods of heating. Since it is no longer necessary in this case to heat the material to such an extent convectionally, it is possible to avoid caking and the formation of deposits, and thus to considerably improve the quality of the reclaimed rubber.