Value-in-use model for chlorination of titania feedstocks
S Maharajh, J Muller, JH Zietsman
In the chlorination process for TiO2 pigment production, blends of titania
feedstocks such as ilmenite, synthetic rutile (SR), natural rutile, upgraded
slag, and chloride-grade slag are reacted with coke and chlorine at a
temperature of around 1000°C to form TiCl4 (the main product) and other
waste metal chlorides. The TiCl4 is the main feed material for the TiO2
pigment-making process. Feeding different titania materials to the
chlorinator affects the amount of coke and chlorine required for the
process, the amount of waste generated, waste disposal costs, the amount
of TiCl4 produced, and bed build-up rates. These factors influence the
value of the feedstock. Generally, a higher TiO2 feedstock is more valued
since less waste is generated and less reagents are consumed. To quantify
the impact of different feedstocks on the chlorinator, a techno-economic
model was developed to describe the chlorination process and estimate
process variables at steady state. This paper describes the development of
the model and studies in which the model has been used to quantify
effects of using different feedstocks.
Keywords: titania feedstock, chlorination, process modelling TiCl4, value-in-use.