Reaction Shaft Research Articles

Thermodynamic Consideration for Oxygen Pressure in a Copper Flash Smelting Furnace at Toyo Smelter

Based on the emf measurements of the galvanic cell (Fe, MgO/O in slag or matte) and the equilibrium calculations, the oxygen pressure in a copper flash smelting furnace at Toyo smelter is discussed. The variation of oxygen pressure in the vertical direction of the reduction shaft is significantly affected by the performance of the concentrates-burner. The oxygen pressure calculated by the equilibrium model is much lower than that measured in the actual furnace. This discrepancy is attributed to the excess magnetite which is contained in the furnace charge and formed in the upper zone of the reaction shaft.

自溶炉シャフト内における銅精鉱の酸化反応に関する基礎的研究

Dry copper concentrates containing principally chalcopyrite and silica were flashed at 1300°C in a vertical reaction shaft to the products corresponding to the matte of 40 to 80% copper with the theoretical blast volume to concentrate ratios.The shaft products were examined by means of X-ray diffraction, microscopic observation, EPMA and chemical analysis.In the reaction shaft, iron and sulfur began to be oxidized with the mole ratio of iron/sulfur equal to 2/3 after chalcopyrite liberated only one eighth of its sulfur. The bulk of iron oxide was magnetite.When the copper content in residual sulfide reached about 50%, oxidation of copper sulfide to cuprous oxide proceeded in much smaller amounts than iron oxidation.The ratios of Fe3+ (O)% to Fe2+ (O)% in the shaft products from the copper concentrate containing 5% silica were higher than those from the copper concentrate containing 10% silica. On the contrary, the fractions of copper oxidized in the former were lower than those in the latter.

Flash smelting of lead concentrates

In this process, the concentrate is directly smelted in the flash furnace reaction shaft, and very high grade lead concentrates can be used without dilution by return slag, etc. The only fluxes needed are those required to make a suitable slag composition with the gangue of the concentrate. This means a much smaller slag fall than found in conventional lead smelting operations and thus lower lead losses in the slag.