Recovery of magnetite fines from sponge iron sludge and preparation of colloidal magnetite from hematite fines by precipitation in presence of poly vinyl alcohol

Abstract

Two waste materials viz., sludge and iron ore fines generated at a sponge iron plant were taken up with a view to utilize the same. The recovery of magnetite fines from the sludge was studied by using the conventional beneficiation techniques such as hydrocyclone, tabling and magnetic separation. The results indicate that magnetite fines with 59% Fe, can be obtained by low intensity magnetic separator or the combination of hydrocyclone and magnetic separator from the sludge containing - 27% Fe. The iron ore fines, the other waste material generated at the plant, was upgraded to 67.5% Fe by a simple flow sheet involving conventional screening at two different sizes. The below 100 mum size fraction (screen rejects) was utilized for the preparation of colloidal magnetite by precipitation technique and stabilized in the presence of poly vinyl alcohol (PVA). The magnetite could be well dispersed in presence of 1.2 wt% of PVA. The results obtained during the coarse of the investigation are discussed in the paper.