The invention relates to multi-stage cement calcining plant suspension preheater of the kind mentioned in the introduction, wherein the preheater comprises a top separator comprising a central tube entering the top separator in a lowermost part of the separator housing whereas the central tubes of the bottom separators enters the separator housing in an upper part of the separator housing.

A calcination unit able to decarbonate raw materials intended for clinker production, the unit including: a main duct in which the raw materials circulate according to a first movement direction, the raw materials being calcined in the main duct; a solid fuel supply duct opening onto the main duct via a fuel outlet, the solid fuel moving according to a second movement direction; a retaining device located in the main duct and arranged opposite the solid fuel outlet so that the solid fuel arriving in the main duct via the fuel outlet passes through the retaining device.

A method for the thermal treatment of dispersible raw material may involve introducing raw material into a riser tube that is perfused by hot gases and thermally treating the raw material with the hot gases. Furthermore, the method may involve feeding a fuel to the riser tube. The fuel may initially dwell in a fuel-conditioning region on a bearing face, where the fuel comes into contact with a part of the hot gas that is mixed with the raw material. Consequently, the fuel is dried and/or at least partially de-gassed and/or at least partially reacted and subsequently transferred into the riser tube.

A calcination unit able to decarbonate raw materials intended for clinker production, the unit including: a main duct in which the raw materials circulate according to a first movement direction, the raw materials being calcined in the main duct; a solid fuel supply duct opening onto the main duct via a fuel outlet, the solid fuel moving according to a second movement direction; a retaining device located in the main duct and arranged opposite the solid fuel outlet so that the solid fuel arriving in the main duct via the fuel outlet passes through the retaining device.

Process for operating a cement or lime plant comprising a cement or lime kiln and a calciner, wherein heat is generated by combustion of a fuel in the kiln and/or calciner, wherein a gas fed to the kiln and the calciner or to the calciner for combustion of the fuel contains an oxygen rich exhaust gas from a bioreactor containing photoautotrophic organisms and wherein the plant is preferably operated in the oxyfuel mode by using exhaust gas from the kiln and/or calciner together with the oxygen from the bioreactor as the gas fed to the kiln and/or calciner for combustion of the fuel.

The present invention provides a fluidized calciner which can perform sufficient calcination by reducing a rate of unburned fuel at an outlet of the fluidized calciner while preventing occlusion in a preheater. In the present invention, plural pulverized coal blowing lines (3), raw material chute (4) of cement raw material, and first to fourth air introduction pipes (5a to 5d) are connected to a bottom side wall of a tubular furnace body (2) whose upper end portion is closed by a top plate (2b); a fluidizing air blowing port (2a) adapted to blow in fluidizing air is disposed at a bottom of the furnace body (2); an exhaust gas duct (6) is connected to a top side wall of the furnace body located above the first and/or second air introduction pipes (5a, 5b) by being spaced away from the top plate (2b); and blowing ports (3a) of the pulverized coal blowing lines are disposed below suction ports of respective air introduction pipes (5a to 5d) but above the fluidizing air blowing port (2a), and at least one of the blowing ports (3a) is placed below the third or fourth air introduction pipe (5c or 5d).

A powder metallurgical component has a chromium content of at least 80% by weight and pores and/or oxide inclusions which are present in the component. The number per unit area of a sum of pores and oxide inclusions at a cut surface through the component in at least one region is at least 10,000 per mm.sup.2.

A method to thermally convert alternative fuels within a loop seal reactor by utilizing preheated/calcined cement meal as the heat source within which alternative fuels are immersed, subjected to drying, pyrolysis and subsequently charred, and an apparatus utilized to practice such method.

The invention relates to multi-stage cement calcining plant suspension preheater of the kind mentioned in the introduction, wherein the preheater comprises a top separator comprising a central tube entering the top separator in a lowermost part of the separator housing whereas the central tubes of the bottom separators enters the separator housing in an upper part of the separator housing.

A method of heating solids in a reactor to produce a heat-treated material, such as a cementitious, a supplementary cementitious, or a pozzolanic material, includes conveying the solids through the reactor from a feeding end to a discharge end so as to form a material bed extending from the feeding end to the discharge end; heating the solids during the conveying to at least 600 C. to transform the solids into the heat-treated material, wherein the heating includes applying radiative heating to the material bed from above and/or from the sides, wherein the radiative heating contributes at least 60% of the thermal energy needed for the heating, and wherein the material bed is mobilized during the conveying in order to renew the surface of the material bed that is exposed to the radiative heating.