Abstract: A process for forming cement clinker using mill scale that may have hydrocarbons associated therewith. Normal feedstock material is preheated and then transferred to a combustion area. The mill scale is also transferred to the combustion area where, during the process of burning a material, the unwanted hydrocarbons are volatilized and converted to harmless gaseous products (by combustion) that can be passed to the atmosphere. The combustion area may be a precalciner or may be the feed end of the rotary kiln if the rotary kiln has an adequate temperature profile. The remaining mill scale and feedstock material are thoroughly mixed and blended and the mill scale is diffused and combined with the feedstock material as the mill scale and the feedstock material move from the feed end toward the heat-source end of the rotary kiln to form cement clinker.

Abstract: A method of disposing of undesirable chemical compounds in waste dust generated in a first kiln in the manufacture of cement clinker by using the dust and slag as the feedstock material to a second kiln, heating the feedstock material in an oxidizing atmosphere, and raising the heat sufficient to diffuse the waste dust and the slag to form a hydraulic product such as cement clinker and lime but insufficient to volatilize previously precipitated chemical compounds in the feedstock material.

Abstract: A method of disposing of undesirable chemical compounds in waste dust generated in a first kiln in the manufacture of cement clinker by using the dust and slag as the feedstock material to a second kiln, heating the feedstock material in an oxidizing atmosphere, and raising the heat sufficient to diffuse the waste dust and the slag to form a hydraulic product such as cement clinker and lime but insufficient to volatilize previously precipitated chemical compounds in the feedstock material.

Abstract: A lightweight aggregate and a process and apparatus by which FCC, petroleum equilibrium fluid-cracking catalyst, a by-product of the oil refinery industry, can be added to the feedstock materials fed into the feed end of a rotary lightweight aggregate kiln or blown into the discharge end of the same kiln by insufflation, or by a combination of both techniques, to form the lightweight aggregate utilizing the FCC as received without further processing.

Abstract: A process and apparatus by which blast-furnace slag can be added to the feedstock materials fed into the feed-end of a rotary cement kiln to form cement clinkers. The blast-furnace slag is crushed and screened to provide blast-furnace slag particles having particles with a predominant size of up to a maximum diameter of substantially 2" or less.

Abstract: A process and apparatus by which steel slag can be added to the feedstock materials fed into the feed-end of a rotary cement kiln to form cement clinkers. The steel slag is crushed and screened to provide steel slag particles having a maximum diameter of 2".