Abstract: A calcining combustor for the suspension preheater of a rotary kiln cement manufacturing plant having a cooler for the clinker comprises an upright furnace vessel having an outwardly spiraling gas exhaust duct at its upper end leading to a preheater gas/meal separator and a mixing portion at its lower end; an inlet for hot combustion air from the cooler into the mixing portion; an inlet for cement meal from the preheater into the mixing portion downstream from the combustion air inlet to entrain the meal in the rising combustion air; and burners for injecting fuel into the air/meal stream downstream from the meal inlet to calcine the meal by heat released by burning of the fuel with the combustion air.

Abstract: A multi-stage cement calcining plant suspension preheater has a calcining combustor flow connected with a cyclone separator in the uppermost stage and helical duct inertial separators in the remaining stages which are lower in height and in pressure drop than conventional cyclone separators and permit reduction in height of the preheater tower and use of a lower horsepower fan to move kiln-off gases through the preheater.

Abstract: A helical duct separator particularly suited for use in the suspension preheater of a cement calcining plant to separate raw cement meal from kiln-off gases in which the meal is suspended comprises a hollow elongated continuous duct having its longitudinal axis disposed along a downwardly inclined helical path, an inlet opening in a vertical plane for receiving a horizontal stream of gas with entrained meal, a downwardly inclined upper wall and a concave outer sidewall in the path of the gas stream to deflect the gas stream into a downwardly inclined helical path, a horizontal bottom wall adjacent the outlet end of the duct, a meal exit opening in the bottom wall and a gas exhaust opening in a horizontal plane in the upper wall adjacent the outlet end of the duct.

Abstract: A suspension preheater adapted to be connected to the feed end housing of a rotary kiln or the like, whereby kiln exhaust gas emerging from the feed end housing passes through the preheater in countercurrent heat exchange relation with particulate feed material for the kiln which passes through the preheater from a feed inlet end contiguous the upper end of the preheater to a feed discharge end at the lower end of the preheater, comprising one or more cyclone means arranged in series gas and particulate feed material flow relation with respect to each other, means for admitting the particulate feed material from a feed material supply source to the upper portion of the preheater, a hollow preheating chamber at the lower portion of the suspension preheater, the hollow preheating chamber having the upper end thereof in gas and material flow communication with the upper end of the lowermost of the cyclone means, the lower end of the hollow preheating chamber being in gaseous flow communication with the feed end

Abstract: Our invention relates to the feeding of sodium to aluminum containing silicon as an alloying element in hypoeutectic percentages by flowing the molten aluminum through a trough and feeding a tube which contains sodium within it into the aluminum in the trough, the tube being preferably fed in countercurrent direction with special mixing and a protective surface coating for the flowing molten aluminum. The invention appears primarily applicable to casting large masses of aluminum such as are used in the melts which produce aluminum ingots for sale to foundries.