What kind of changes are required in raw mix to increase the granulation with 50 per cent pet coke total CV 4.3 per cent, LSF 93, SM-2.1 per cent, AM-1.0 per cent, in kiln feed?

The granulation problems with pet coke firing arise because of the low viscosity of the flux caused by the sulphur in the pet coke. Therefore raising the silica and alumina modulii should help to improve the granulation.

If air cooled slag is used as a raw material for kiln , replacing uncalcined calcium carbonate, will the calcium silicates, aluminates, etc. revert back to free state, so they can reform clinker crystals of cement design proportions? Will the existing sicates go to C₂S state with the increased temperature and time. In other words could this slag combined with correction proportions of silica, iron, alumina, calcium be used as a primary raw material for a kiln feed? If there is a reversion of the state of the compound will there be a requirement for additional heat (as opposed to the exothermic heat released to compound formation) ? Would there be any big color changes if air cooled slag was used as a primary raw material.

The process of adding air-cooled slag to the kiln inlet has been patented by TXI under the name Cemstar. The minerals in the slag do not convert back to the free state. They are already intermediate states in the formation of Portland cement clinker and all that is required is the completion of exothermic combination to C₃S. No additional heat is required, also there are no reported changes in the colour of the cement subsequently made from the clinker.