Reactor for carrying out chemical and physical materials transformations, which comprises a reaction space enclosed by a reactor housing, where the reactor housing has at least two lateral fluid inlets having adjustably mounted nozzles which include an angle of about 20-160 degrees and through which fluid jets which impinge on one another at a common collision point within the reaction space are passed and the reactor has a fluid outlet at the bottom of the reaction space, which is characterized in that—an exchangeable bottom plate•which has a hole as fluid outlet and•on which moveably supported spheres are located so as to block the original path of the individual fluid jets in the unaligned state rests on the bottom of the reaction space and—a half shell standing upright on the bottom of the reaction space is located between each moveably supported sphere and the wall of the reactor space and—bottom plate, half shell and moveably supported spheres comprise one or more hard materials.