Assessment of the effect of iron magnetic concentrate desulfurization by flotation method on the quality of green and cooked pellets: A laboratory and pilot-scale study

Abstract

The effect of flotation for desulfurizing the iron pelletizing feed has been investigated. The flotation method can reduce the emission of harmful environmental gases during the pelletization process by reducing the concentrate's sulfur content. On the other hand, flotation causes a change in the Blaine of the iron concentrate and wastes some magnetite particles. In this research, the samples were collected from the iron concentrate grinding circuit product in the Golgohar pelletizing plant. They were subjected to flotation tests on a laboratory and industrial scale. In addition, the properties of pellets produced before and after desulfurization by flotation were investigated. The results showed that using flotation, iron and sulfur grades changed from 66.08% and 1.12%, to 68.3% and 0.33%, respectively. Although flotation reduces the Blaine number of the pelletizing feed from 1800 to 1512 cm2/g, this reduction is mainly due to the removal of fine clay particles and did not harm pellet oxidation. Decreasing the sulfur content of the iron concentrate feeding to the pelletizing process led to an increase in the quality of raw and cooked pellets in terms of increasing the cooking speed (5%), increasing the compressive strength (13%), and reducing the residual FeO (2%), together with less emission of SO2 to the environment.