Study On Modification Of Ausmelt Furnace Copper Slag And Recovery Of Copper And Iron From It

The copper slag contains large amounts of copper, iron and sparse precious metal.The grade of copper and iron are respectively1%and40%, which are much higherthan the averagerecoverable ore grade for iron and copper smelting. The copper slagis a large quantity and high quality secondary resource.The treatise is target at Daye Nonferrous Metals Company Ausmelt furnacecopper slag. Based on the property and characteristic of the copper slag, copper andiron were recovered by modified treatment, which realized the resources of copperslag utilization.The mineralogy of this Ausmelt furnace copper slag was studied by using opticalmicroscope, scanning electron microscope(SEM), multi element analysis, the X-raydiffraction and phase analysis, which indicates that the iron grade of the residues is43.74%and the copper grade is0.99%. In the copper slag, iron mainly exists in theform of fayalite and magnetite, while copper mainly exists in the form of coppermatte and copper sulfide.A combination of roasting-leaching-magnetic processing flow was applied in thebeneficiation of iron in the copper flag. It was demonstrated that iron concentrate withthe grade of61.52%and the recovery of82.26%can be obtained by dilute acidleaching and magnetic separation treatment after calcining for60minutes at thetemperature of900℃,10%sodium carbonate consumption, while the concentrationof sulfuric acid is18.7%, the leaching temperature is20℃, the ratio of liquid to solidis4:1, the leaching time is40min, the magnetic field intensity is480kA/m. Themineralogy of this copper slag was studied by using thermo-gravimetric analysis anddifferential scanning calorimetry(TG-DSC), the X-ray diffraction, analysis ofthermodynamics of roasting, which indicates that fayalite mainly decomposed intomagnetite and the addition of sodium carbonate can promote the decomposition of thefayalite.The research on the flotation of copper was carried out after the copper slagcalcined. The copper slag which added10%sodium carbonate and15%pyrite roastedunder temperature of1250℃for30min,the particle size of roasted residues smallerthan74μm account for91.37%. The appropriate flotation process conditions wereobtained. The pulp pH is6.5, the collecting agent is60g/t, the foaming agent is50g/t.The copper concentrate grade is2.87%, recovery rate is87.99%. In this situation, the iron concentrate which the grade of57.02%and the recovery of47.71%can beobtained while the flotation slag leached under the condition that the concentrationsulfuric acid is18.7%, the leaching temperature is20℃, the ratio of liquid to solid is4:1, the leaching time is40min, the magnetic field intensity is480kA/m.The reaction of roasting and leaching process were analyzed by thethermodynamics method.