Abstract: Regeneration of hydrochloric acid by hydrolysis of iron chloride in aqueous solution employs a Pelletiser (5) after preconcentration of acid solution in a "Pre-Evaporator" (1). Pelletiser (5) controls pellet mixture to between 12% and 14% free water by recycling dried solids from Roaster (3), from Screen (7), or from dust removal Cyclone (9), and waste liquid from Preconcentrator (1). Preconcentrator (1) is contacted with superheated gas from Fluid Bed Roaster (3). Rotary Drier (6) dries pellets with a concurrent hot gas stream and the pellets are screened at (7) with oversize being sent to a Mill (8), undersize recycled to Pelletiser (5), and sized feed delivered to Roaster (3). HCl is produced as gas offtake from Preconcentrator (1) and passes via a demisting Cyclone into adiabatic Absorption Process section (11), where weak acid liquor and water (10) are added as required.

Abstract: A process for enhancing ilmenite from deposits of mineral sands or mineral concentrates comprises a single stage fluidized bed magnetizing roast (16). A temperature of 650.degree. C.-900.degree. C. in an excess of a carbonaceous fuel (such as coal/char, CO or hydrocarbon) is used to provide an atmosphere in which the oxygen potential is controlled resulting in a consistently high magnetic susceptibility product. Roasting has been used before but the current process requires a lower intensity magnetic separation stage (18) and provides improved recovery (even of tailings produced by prior art roasting process). Annealing (17) of the roasted product improves the resultant magnetic susceptibility. Ilmenites having inclusions or selvedges of silicate minerals are further improved by employing a grinding step after magnetic separation prior to slagging or use as synthetic rutile feedstock. The roasting stage potentiates the ilmenite for leaching in the production of synthetic rutile.