Abstract: A method and apparatus for continuous pressure comminution of brittle grinding stock such as cement clinker wherein simultaneous operations of unit grain comminution and product bed comminution are carried out in the roller gap of the same roller machine in such a manner that the grinding stock is first precomminuted by means of the unit grain comminution in a wider roller gap and immediately thereafter, the grinding stock fragments produced in the unit grain comminution are further comminuted by the technique of product bed comminution in the region of the narrowest roller gap. The continuous pressure comminution is characterized by a high pressure of more than 2 metric tons per centimeter of roller length, with a sifter being provided after the pressure roller.

Abstract: A method and mechanism for calcining cement wherein the material is preheated in a precalcining zone and a vertical conduit leads heated discharge gases upwardly from a main calcining furnace, a supply of fuel and a supply of oxygen is fed to a preoxidation zone beneath the precalcining zone and raw material is fed into an admixing area above the burner with a deflector preventing particles from falling down into the preoxidation zone with the fuel being partially oxidized so that controlled heating and controlled oxidation occurs in the precalcining zone.

Abstract: A method and mechanism for calcining cement wherein the material is preheated in a precalcining zone and a vertical conduit leads heated discharge gases upwardly from a main calcining furnace, a supply of fuel and a supply of oxygen is fed to a preoxidation zone beneath the precalcining zone and raw material is fed into an admixing area above the burner with a deflector preventing particles from falling down into the preoxidation zone with the fuel being partially oxidized so that controlled heating and controlled oxidation occurs in the precalcining zone.

Abstract: A process and mechanism for thermally treating fine ground material for the calcining of cement in stages which passes finely ground calcareous and argillaceous material into a vertical chamber to enter a deacidifying zone, supplying fuel to the vertical chamber with a supply of oxygen so that the fuel is partially oxidized prior to mixing with the material and the fuel, oxygen and material are supplied so that the material is deacidified in the range of 50% to 80%, passing exhaust gases from a kiln into the deacidifying zone, and passing material from the deacidifying zone through a cyclone separator to separate the gases and deliver the preheated material to the kiln for completion of the burning process.