New Technology for Indirect Thick Slurry Heating

摘要

In the pre-desilication of Bayer bauxite slurries, the first step is to heat the slurry to ～100°C. Direct steam injection adds unwanted dilution that has to be removed by additional evaporation, resulting in capital and operating cost impacts, and production losses.With indirect heating, the nature of thick, viscous slurries can lead to accelerated scaling on tube walls and rapid reduction in heat transfer resulting in short operating cycles. Often these fundamental issues render indirect heating uneconomic against direct steam injection.This paper describes a new technology developed and patented by Hatch for Indirect Heating of Thick Slurry, which overcomes all of the issues above. This technology has been successfully trialed using a full size pilot plant and installation of the first commercial scale project is currently progressing. The safety, technical, operational and cost advantages are discussed.