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

ABSTRACT

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 Quadrilátero Ferrífero-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.

KEYWORDS:

• Iron ore slime
• dispersion
• flocculation
• starch
• polyacrylamide

Acknowledgments

The authors are thankful to CAPES and CNPq for the master’s degree and researcher scholarships, to Vale S. A. for funding the project, to FAPEMIG for the purchase and maintenance of the equipment used in this study, and to UFOP for the resources used in the publication of this work.

Disclosure statement

No potential conflict of interest was reported by the author(s).