Selective Flocculation/Magnetic Separation of Ultrafine Iron Ore Particles with Corn Starch and Polyacrylamides: A Comparative Study

This paper presents the results of a selective flocculation/magnetic separation study performed with a sample of iron ore slime from the desliming stage of the industrial flotation circuit of a mine in the southern region in the Quadrilatero Ferrifero-Brazil that was discarded in a tailings dam. Zeta potential measurements of pure minerals previously identified in the sample (goethite = 52.4%, hematite = 26.2%, quartz = 12.3%, kaolinite = 8.2%, and others = 0. 9%) were evaluated to assess the influence of the reagents used (sodium hexametaphosphate - SHMP (dispersant)) and flocculants (corn starch, nonionic polyacrylamide - P2500 and cationic polyacrylamide - P806)) on their surface properties and consequently on the stability of suspensions of the slime and of the pure minerals individually, aiming to establish conditions for selective separation between Fe-bearing minerals (goethite and hematite) and gangue minerals (quartz and kaolinite) in the subsequent magnetic separation step. At pH 10 and a 25 mg/L dosage of SHMP, a higher Fe recovery was verified with starch (2000 g/t) in relation to nonionic and cationic polyacrylamides, and similar Fe contents in all dosages tested of the flocculants.

Automated summary

This paper presents the results of a study on selective flocculation/magnetic separation of iron ore slime from a mine in Brazil. The study evaluated the zeta potential of different minerals in the slime and the influence of reagents and flocculants on their surface properties. The aim was to establish conditions for the selective separation of iron-bearing minerals and gangue minerals. The results showed that starch was more effective in achieving higher Fe recovery compared to polyacrylamides.