Abstract: A method and apparatus for introducing solid, liquid or gaseous fuel into a burning zone of a rotary kiln for manufacturing cement clinker. Fuel is conducted through a duct or ducts and primary air is conducted through at least two annular ducts arranged substantially concentrically with, and around, the fuel duct(s), the portion of air in one of the air ducts flowing substantially axially, whereas the portion of air in the second of the air ducts comprises air which has a rotary component about the center axis of the burner, and wherein the amount of primary air in the two portions is independently controlled, such that the two portions of primary air are mixed at a lower velocity in a collecting duct into a single primary mixed airstream having a desired axial/rotary flow characteristic, and wherein this airstream is subsequently accelerated up to a desired, higher discharge velocity.

Abstract: A bed (6; 78) of particulate material, which is supported by a gas distribution bottom (9; 75), is located utilizing a treatment gas, which via ducts (19; 35; 77) is conducted in sectionalized manner to and directed up through the gas distribution bottom and the bed of material from one or several underlying compartments (15; 76). The flow of the treatment gas through each duct (19; 35; 77) is self regulated by means of a flow regulator (21) provided in each duct. It is thereby obtained that the total pressure loss across the gas distribution bottom can be reduced, that the flow of the treatment gas through the material bed is distributed in a desirable and well-defined manner across the entire gas distribution bottom regardless of the composition of the material bed and the distribution thereon, and that tunnel formations are avoided.

Abstract: A method for the continuous treatment of particulate material, such as cement raw meal, in an apparatus comprising a stationary reactor (6) configured as a conical spouted bed, to which the material is fed and treated in a suspended bed by means of gas which, via a centrally arranged gas inlet (21), is injected at the bottom of the reactor (6) and flows upwards through the reactor (6), and wherefrom the material is discharged via an opening (21) at the bottom of the reactor (6).

Abstract: There is disclosed a method for reducing the NOx emission from a kiln plant for heat treatment of raw materials, in which kiln plant fuel can be fired in at least three zones an amount c of fuel is burned, in a second of these zones an amount b of fuel is burned and to this second zone the NO containing exhaust gases from the other at least two zones are also fed. In the rest of these at least three zones an amount a of fuel is burned and at least a part of the raw materials are fed to these zones together with an oxygen containing gas. The total amount of fuel, b+a, burned in the second and in the last zones is determined by the need for treatment of the raw materials. When the kiln plant is used for manufacturing cement clinker the heat treatment consists of preheating, calcining, sintering and cooling of the mineral raw materials.

Abstract: The present invention relates to a plant for manufacturing cement clinker. The plant consists of a preheater, a calciner in which the raw material is calcined at a temperature of more than 800.degree. C. and where fuel and oxygen-containing gas are fed to the lowermost zone of the calciner, and a kiln. The object of the invention is to provide a plant for manufacturing cement in which it is possible to bum lumpy fuel in a calciner, while simultaneously maintaining the possibility of increasing the time of retention and possibly the temperature of the material being fed to the lowermost zone in the calciner. This object is achieved according to the invention in that the calciner is provided with a fixed bottom (27) allowing combustible material fed to the calciner to be deposited on the bottom and in that oxygen-containing gas is fed horizontally to the calciner through openings in the lowermost zone of the calciner.

Abstract: The invention relates to an apparatus and a method for manufacturing clinker, such as cement clinker, in which the majority of the raw materials is present in a hydrous slurry.Initially, the slurry is dried in a gas suspension drier, and the raw materials are subsequently passed to a thermal unit in which the heating of the raw material is effected fairly quickly so that all organic compounds are destroyed in the thermal unit.Subsequent to being heated in the thermal unit, the raw material is directed to the kiln in which it is nodulized and burned into clinker.

Abstract: A method for grinding of material in a ring roller mill having at least one grinding ring, at least one roller fitted in the grinding ring and at least one unit fitted between the roller and the grinding ring. The method includes the steps of operating the mill at a subcritical speed and at a grinding pressure above 40 MPa, placing the unit in the path where compacted material is released from the ring at a certain distance from a point P, which is the point on the ring where the material is released, in such a way that the unit is hit by agglomerates formed during operation at an angle between 60.degree. and 120.degree., said angle being between the surface of the unit and the direction of incidence of the material, after the latter is released from the grinding ring, and that the loosened material is distributed over the draw-in-zone in front of the roller and over the roller.

Abstract: A cooler (1) for cooling particulate material from a kiln, wherein the material upon entry into the cooler (1) is distributed to a material bed on a stationary supporting surface (11) in the form of a tray, while cooling gas, such as atmospheric air, is blown up through the material bed from injectors in the tray in a uniform and evenly distributed manner. The material is conveyed forward across the supporting surface (1) and through the cooler (1) by means of a separate mechanical conveying device (17). It is thus possible to split the three functions of such a cooler, viz. to support the material, to distribute the cooling gas across the supporting surface and to convey the material forward across the supporting surface, into functions which are independent of one another, so that each function can be optimized.

Abstract: The present invention relates to a ring roller mill which, among other things, can be used in connection with the manufacture of cement for grinding of mineral clinker materials, slags, and similar materials. The mill has a grinding ring 1 and a roller 2. Between the roller 2 and the grinding ring 1, the partially crushed material forms a grinding bed 4 and on each side of the grinding ring 1 dam rings 5 are fitted. On the outer side of the dam rings 5 are fitted collecting jackets 6, to which scoop plates 7 are fixed. The jacket collects the material which flows over the dam ring and by means of the scoop plates the material is lifted round with the collecting jacket. Since the speed of the jacket is lower than the critical speed, the material will drop off from the uppermost part of the jacket, being dispersed towards the bottom of the latter, and is subsequently returned to the grinding path.

Abstract: The invention relates to a method for manufacturing cement clinker whereby the raw meal is initially subjected to preparatory processing, e.g. by comminution, homogenization and/or drying, and, eventually, nodulized and burned, with the nodulization process itself taking place in a stationary burning reactor. By the method according to the invention a sulphatic compound is added to the raw meal in a sufficient quantity before introducing the raw meal into the stationary burning reactor or directly into the stationary reactor, e.g. through the combustion air or together with the fuel. The sulphatic compound may be selected among all types of sulphates which will not affect the properties of the finished cement. It is particularly advantageous to use calcium sulphate, either naturally occurring or industrial by-products and regular waste materials, e.g. used absorbent from dry exhaust gas desulphurization.

Abstract: A grate element (1) for a grate surface, e.g. in a clinker cooler, is shaped in the form of a box between the walls (3, 4) of which a number of surface-defining grate bars (5, 6) are mutually arranged so that, between them, they form fine gas channels (7). The grate bars (5, 6) alternately consist of bars (5) having a substantially rectangular cross section and bars (6) having a cross section substantially of the form of an inverted T. The rectangular bars (5) overlap the transverse sections (6a) of the T-bars, each of which is provided at the free end with a projecting, longitudinal bead (17), whereas each of the rectangular bars (5) at the sides facing the T-bars (6) are correspondingly configured with depending, longitudinal beads (15).

Abstract: A description is given of a plant for heat treatment of lumpy material, such as limestone, other carbonate materials, cement raw materials, or the like. The plant comprises a preheating zone, a burning zone, and connecting means which connect the material outlet of the preheating zone to the material inlet of the burning zone. A separating device is provided as a part of the connecting means and consists of a duct through which a gas stream can be induced to flow from below and upwards. On entry into the separating duct at the top of the duct, the preheated material will be dispersed in the counterflowing gas stream, whereby the material is divided into a fine fraction which suspended in the gas can be discharged via the discharge means provided at the upper end of the duct, and a fall-through coarse fraction which is normal manner can be fed via a connecting means to the material inlet of the burning zone.

Abstract: A description is given of a rotary drum, as for example a rotary kiln, which is suspended within a live-ring by means of axially extending brackets which are retained by the live-ring and bearing, at their free ends, against retaining elements fixed to the rotary drum, in such a way that the vertical load of the drum relative to the drum shell is transmitted tangentially to the live-ring. The brackets are evenly distributed over the circumference of the live-ring fixed to its side faces. Hereby, the live-ring can be made with a smooth cylindrical inner face without teeth, which, besides being advantageous from an economic perspective, also makes it possible to use existing live-rings of the migrating type. Further, all parts of the device will be more readily accessible in connection with inspection and maintenance work in that none of the parts are concealed under the live-ring.

Abstract: The present invention relates to a ring roller mill which, among other things, can be used in connection with the manufacture of cement for grinding of mineral clinker materials, slags, and similar materials. The mill has a grinding ring 1 and a roller 2. Between the roller 2 and the grinding ring 1, the partially crushed material forms a grinding bed 4 and on each side of the grinding ring 1 dam rings 5 are fitted. On the outer side of the dam rings 5 are fitted collecting jackets 6, to which scoop plates 7 are fixed. The jacket collects the material which flows over the dam ring and by means of the scoop plates the material is lifted round with the collecting jacket. Since the speed of the jacket is lower than the critical speed, the material will drop off from the uppermost part of the jacket, being dispersed towards the bottom of the latter, and is subsequently returned to the grinding path.

Abstract: A grate element for a grate surface, e.g. in clinker cooler, comprises a top plate which is shaped in the form of a box having a surface which is plane at one end, whereas at the other end it consists of in cross section downwardly curved slats which, between them, form slots. The grate element further comprises a corrugated bottom plate which is provided with longitudinal rows of slots and projections rising into the slots of the top plate, and gas channels which are defined by the underside of the slats of the top plate and the upper side of the bottom plate, and open at the slots in the two plates. Accordingly, the top plate of the grate element is effectively cooled, the pressure loss through the grate element is appropriately large, the grate element is protected against falling-through of material and maintenance work in connection with the replacement of grate elements is facilitated.

Abstract: A method and plant for heat treatment of lime sludge (CaCO.sub.3) formed by the causticizing process during the manufacture of paper pulp. The lime sludge is dried and pulverized in a first process stage and preheated in a second process stage by means of hot exhaust gas coming from a kiln. In order to ensure that the temperature in the second process stage does not exceed a predetermined temperature lying within the range from 400.degree.-600.degree. C., the relationship between the amount of energy available in the exhaust gas for preheating in the second process stage and the amount of accumulated energy in the material which is to be preheated is regulated.

Abstract: A method and apparatus for controlling the temperature in a kiln in which cement clinker is manufactured. The temperature is controlled by controlling the fuel rate to the kiln. The fuel rate is adjusted according to a calculation that is made of the sulphur evaporation in the kiln, thereby obtaining a measure of the instantaneous temperature in the burning zone. The evaporation factor is calculated on the basis of measurements of the sulphur content in the cyclone material which passes to the kiln or a measurement of the sulphur content in the exit gases out of the kiln.

Abstract: A cooler (1) for cooling particulate material from a kiln, wherein the material upon entry into the cooler (1) is distributed to a material bed on a stationary supporting surface (11) in the form of a tray, while cooling gas, such as atmospheric air, is blown up through the material bed from injectors in the tray in a uniform and evenly distributed manner. The material is conveyed forward across the supporting surface (1) and through the cooler (1) by means of a separate mechanical conveying device (17). It is thus possible to split the three functions of such a cooler, viz. to support the material, to distribute the cooling gas across the supporting surface and to convey the material forward across the supporting surface, into functions which are independent of one another, so that each function can be optimized.

Abstract: The invention relates to a method and a plant for manufacturing mineralized portland cement clinker. The method and plant provides for preheating, calcining, burning and finally cooling the clinker. The mineralizer may e.g. be gypsum, fluorine, or a waste product containing these or other mineralizers. The mineralizer is added to the feedstock after the feedstock has been fed to the process, preferably after the cyclone which handles the feed to the calciner, i.e. the last cyclone in the preheater, or the lowermost preheater stage in a plant which does not incorporate a calciner.

Abstract: A ring roller mill for grinding mineral clinker materials and the like comprises at least one grinding ring, at least one roller and at least one air outlet opening within the outer circumference of the grinding ring and air inlet openings on each side of the air outlet opening in the rotating direction of the grinding ring. The location of the air inlet and outlet openings, and respectively, relative to each other ensure that substantially lower flow rates occur in the mill at a certain volume flow rate compared to hitherto known mills. At the same time a more stable operation of the mill is ensured.