Abstract: An apparatus for preheating particulate material in which the particulate material is transferred from one or more upper storage bins to a circular lower chamber that has an outer, essentially annular, portion which serves as a gas flow passage. The particulate material is directed from the feed bin or bins into a plurality of essentially vertical cylindrical feed cassettes via intermediate feed ducts. The lower chamber has a flat roof which is in contact with the bottom portion of the vertical feed cassettes. The vertical feed cassettes are approximately evenly spaced on top of the outer perimeter of the flat roof. The particulate material is preheated in the annular flow passage by hot kiln gases flowing in countercurrent heat exchange relationship with the particulate material.

Abstract: The invention relates to a method for heat treatment of fine calcium carbonate bearing material comprising preheating fine material containing a coarse and a fine fraction. The preheated material is delivered into a fluidized bed calcining means wherein the coarse fraction is calcined and the fine fraction is delivered by process air to an adjacent vertically arranged gas flash calciner furnace in which it is calcined.

Abstract: A process of treating dust from a cement manufacturing operation. The process comprises adding carbon bearing material to the dust catch from a cement manufacturing operation to form a mixture, which is formed into nodules and sizing the nodules to obtain a feed material having a selected size range. The nodules are directed as feed material to a fluidized bed which is maintained by passing air for combustion upwardly through a bed of material. The material is thermal processed within the fluidized bed in a reducing atmosphere by supplying fuel for combustion in the fluidized bed to maintain temperatures sufficient to volatilize alkali and sulfur compounds in the feed material and produce a product having an increased concentration of cement forming compounds and reduced alkali and sulfur compounds as compared to the feed material. The reduced clinker is then re-oxidized to minimize/reverse adverse color and mineralogy.

Abstract: Disclosed is a method and an apparatus used in said method, to produce aggregate products from waste material streams. The method comprises combining an encapsulation material with waste materials to form a mix suitable for granulation. This mix is then feed to a granulation means to form particles having a size suitable for thermal treatment in a bed thermal processing means, which can be a fluid bed system or a spouting bed system. In the bed thermal processing apparatus the particles are converted into an aggregate product.

Abstract: With the present invention, a feed preparation system for producing cement includes mixing raw materials with a source of potassium. The mixture is conveyed to feed preparation system where it is placed in condition for treatment in a fluidized bed reactor for thermal processing to produce cement clinker. The potassium combines with the SO.sub.2 generated in the process to form potassium sulfate solids that are filtered from the process gas stream before emission to the atmosphere to thereby reduce sulfur emissions from the fluid bed cement process. The starting material may include white cement raw meal, grey cement raw meal and cement kiln dusts.

Abstract: A process for the continuous production of a calcined product containing a high level of reactive oxide valves, from a preheated raw material containing calcium carbonate values, said process comprising,(a) introducing the preheated raw material to the bottom of a generally vertically oriented gas suspension calcining furnace, whereby said preheated raw material is thereafter suspended in an ascending stream of heated gas to thereby pass vertically upwardly through the gas suspension calcining furnace;(b) passing the ascending gas stream through a plurality of burners, into which fuel and air are injected, that are vertically spaced from each other, in the gas suspension furnace, at a number of levels in the flow direction of the heated gas, and(c) collecting the calcined product.