Abstract: In a process for the production of aluminium a molten alumina slag, containing combined carbon is circulated through one or more alternately arranged relatively low temperature zones where carbon is added to increase the combined carbon content of the slag by reaction with the alumina slag and high temperature zones where aluminium metal is released by reaction of aluminium carbide and alumina in the slag with consequent depletion of the combined carbon content. Alumina is supplied to the slag at one or more locations. The energy to drive the reactions is preferably supplied by resistance heating of the slag particularly in transit from a low temperature zone to a high temperature zone although usually additional energy is supplied to the slag in the return from a high temperature zone to the next low temperature zone.In most instances the aluminium-liberating reaction is carried out in an upwardly inclined passage and the gas evolved is employed to achieve the circulatory movement of the slag.

Abstract: In the calcination of petroleum coke or the like in a rotary kiln, utilizing controlled air supply intermediate the ends of the kiln to burn removed volatiles and thereby generate all or nearly all of the heat required, highly effective control procedure includes establishing and repeatedly re-establishing target values for temperatures of exit gas and discharging product respectively at opposite ends of the kiln, such target temperatures representing conditions of desired position of the calcining zone and desired physical character of the calcined product which is achieved by proper maximum temperature in said zone. The procedure further includes adjusting one or more of the variables of combustion air supply, RPM of the kiln, and green coke feed rate so as to keep the end temperatures at target value.

Abstract: A pyroscrubber for combustion of large carbon particles in a stream of waste gas, particularly the waste gas from a coke calcination furnace comprises a generally U-shaped combustion chamber having a first passage arranged parallel with (preferably above) a second passage, so that there is a reversal in gas flow direction between the two passages. The combustion chamber has an exhaust gas inlet and an array of air inlets at the inlet end of the first passage. A gas outlet preferably leads laterally out of the side of the structure at the outlet end of the second passage to secure an abrupt change in the direction of gas flow.

Abstract: In the calcination of petroleum coke in a rotary kiln, procedure wherein air is controllably supplied internally of the kiln to burn the removed volatiles, as by selection or adjustment of the amount of such air and of the speed of coke travel down the kiln, so that all or nearly all of the heat for calcining the coke is provided by such combustion, and so that a suitably high temperature is reached for effective calcination at an efficiently large feed rate of coke, a special feature being to maintain a significantly long travel time of the coke from a region of intense calcining activity to the product discharge end of the kiln. High production rates, of coke calcined well and uniformly, are economically attained, with ease of control and with unusual stability of kiln operation.