Method of enriching oxide iron-ores, flue dust from blast furnaces, burnt pyrites, purple-ore and the like

摘要

279,797. Aktiebolaget Ferriconcentrat, (Assignees of Mueller, H. A.). Oct. 28, 1926, [Convention date]. Treating ores to facilitate magnetic separation. -Weakly magnetic oxide iron ores. blast furnace flue dust, burnt pyrites, purple ore and the like are transformed by heating in a non-oxidizing atmosphere to a strongly magnetic form of ferric oxide and then separated in a low intensity magnetic separator. Oxide ores are heated at 600‹ C. for “ hour to ¢ hour preferably with a small amount of carbonaceous material, for instance, 0.25-0.5 per cent of powdered coal. Blast furnace flue dust containing ferric oxide and carbon in excess of the required amount is mixed with other ores not containing carbon. Carbonate ores are first heated in air to produce ferric oxide and are then treated as above, preferably in the absence of air. The material is cooled in the presence of air.