Selective flocculation of ultrafine iron ore 2. Mechanism of selective flocculation

摘要

The mechanisms involved in the selective flocculation of hematite from kaolinite, using starch as the flocculant, have been investigated. Adsorption isotherms of starch on hematite and kaolinite were measured by a thermogravimetric method, supported by infrared analysis of the adsorbed species and zeta-potential changes on adsorption of starch. The preferential adsorption of starch onto hematite was proposed to be due to the higher concentration of hydroxylated metal adsorption sites. By comparing selective flocculation performance with adsorption results, it was established that flocculation occurs by the classical bridging mechanism.