Abstract: An improved preheater is provided suitable for use with gas or oil fired reverberatory melting furnaces for recycling aluminum scrap and other scrap metals. The improved preheater comprises a charge box having a bottom, and a chamber having a bed. The chamber is in communication with the charge box at one end, and, an exit at the other. A pusher is provided for pushing the contents of the charge box into the chamber and thus pushing the contents of the chamber towards the exit. The chamber is of uniform expanding dimensions from its one end in communication with the charge box towards the exit. The bed of the chamber carries openings therethrough from a gas chamber therebelow into which heated waste gas is passed for circulation through the openings in the bed through the contents of the chamber.

Abstract: A roller tunnel kiln for firing a drying refractory material advanced along the refractory rotatable rollers includes an upper section comprising a prefiring zone, a firing zone, a first forced cooling zone, a natural cooling zone and a second forced cooling zone. Parallel to the upper section along the length thereof a drying zone is arranged provided with refractory rotatable rollers for advancing movement of the material to be dried. A distributional tunnel is mounted parallel to the drying zone and is connected with the prekiln zone or with the forced cooling zone so that hot gases mixed with cool ambient air are directed into the distributing tunnel provided with openings communicating the latter with the drying zone. The hot gases at drying temperatures are further directed into drying tunnel in the direction opposite to that of the material to be dried.

Abstract: A method of heat treating a preheated, pulverous, raw material consisting of or containing lime, such as cement raw meal. By mixing at least part of the preheated raw material intimately with a fuel capable of carrying out at least a partial calcination, a suspension of raw material in a combustible gas is provided. Upon providing a flow of oxygen-containing gas in contacting relation with the suspension of gas/material, at least a partial calcination takes place according to an endothermic process in which calcium carbonate is dissociated into calcium oxide and carbon dioxide. A finishing calcination and/or other heat treatment may follow the calcination process. When the raw material is cement raw meal, the aforesaid finishing heat treatment following the calcination is a sintering by which cement clinker is produced according to an exothermic process.

Abstract: A heat transfer apparatus for controlling the temperature of a formed workpiece is provided. The apparatus is in the form of a multi-tier rotary preheat, quench and heat recovery tunnel which provides for transfer of heat between tiers from workpieces to be cooled to workpieces to be heated, thereby conserving heat energy. Transfer of heat is accomplished by means of fans interconnected with the tier levels of the tunnel. A control system ensures proper temperature of air, passing through a hot-air fan, which is removed from a second level and transferred to a first level. Means are provided for loading slugs to be preheated prior to forming onto a first annular tray on the first level and for removing same after it has completed a single rotation about the cooling tunnel. After being further heated in an induction furnace, the slug is warm formed in a press to a desired configuration.