Location of Sorbents for Desulphurization Processes in Coal Combustion Applications

A high internal phase water in oil emulsion binder upgraded weathered ultra fine coal discard. At 5 kg/ton on a feed of 29.34 per cent ash and 20.94 MJ/kg, flotation gave a clean coal of 11.76 per cent ash and 28.61 MJ/kg at 15.61 per cent mass yield. Calorific value rose with agitation speed and fell with binder dosage.

Ion exchange applied to brine from a three stage reverse osmosis plant at eMalahleni converted the brine entirely into saleable fertiliser and explosives feedstock, and recovered close to half of the water the reverse osmosis stage leaves behind. On this basis the existing brine pond and the two planned for the plant expansion would not be needed.

Dense medium cyclones on the fine coal fraction lifted product yield well above the spiral circuit they were compared against and gave closer control of product quality. Cut point density control proved the hardest part of running the plant, medium properties being critical. Magnetic separator capacity had to match the duty, and a basement was needed to contain and recover medium spillage.