Investigation of removal methods for the impurities in iron ores

In this study, impurity and alkaline elimination were carried out in sintering batch for sintering and in iron ore concentrates for pelletising by the chloride volatilization process. Besides it was also attempted to reduce the negative effects of chloride volatilization process on the porosity and on the compression strength of sintered pellets.For this purpose magnetite concentrates of Divriği region?s ?A Hill? cite and sintering batch of Erdemir Ereğli Iron and Steel Inc. were used. Spherical pellet production experiments were divided and studied in two different parts, namely with CaCl2 addition and without CaCl2 addition. Experiments done without CaCl2 addition for compressive strength and porosity, the best result among all experiments was obtained by 0.5 % fly ash 0.25 % Ca(OH)2 and % 0.25 Ca bentonite addition which was resulted in 2648 N/Pellet compressive strength and 27.9 % porosity.Best results for impurity elimination efficiency ratio among all investigation on sintering batch which was added as 3% CaCl2 (six times of stoichiometric ratio) in the form of solid powder addition resulted in 41.54 % and 21.09 % for K2O and Na2O respectively whereas 49.09 % and 28.7 % efficiency ratios were found for K2O and Na2O respectively by using 3% CaCl2 addition in the form of solution.The best result among all experiments carried out by CaCl2 added samples with 0.5 % Na-bentonite, 0.3% Ca(OH)2 and 0.3 % fly ash composition and in spherical pellet production with 1.36% CaCl2 containing solution spraying. In the chemical analysis of samples produced by this method alkalines were reduced from 0.11 % to 0.031 % by 71.82 % removal efficiency ratio, sulphur was reduced from 0.4% down to 0.212 % by 47 % removal efficiency ratio, copper was reduced from 0.021 % to 0.017 % by 66.67 % removal efficiency ratio and zinc was also successfully reduced from 0.01 % to 0.001 % by 90 % removal efficiency ratio. Compressive strength and porosity were measured for the best composition as 2726 N/Pellet and 31.0 % respectively.Best results for the basis of grain size distribution was obtained -0.1 mm with 3% CaCl2 powder addition resulted in 69.21 % and 59.13 % impurity elimination efficiency ratio for K2O and Na2O respectively whereas 88.08 % and 73.26 % efficiency ratios were found for K2O and Na2O respectively by using 3% CaCl2 addition in the form of solution.Although the lower elimination efficiency value in the case of solid form additive, it is advised to apply solid form CaCl2 additive instead of solution form not to have corrosion problem of sinter band in industrial applications.