Background: Olivine is an important industrial raw material especially for metallurgical
applications like foundry sand, refractory, slag conditioning, etc. Loss On Ignition
(LOI) value (>1%) is the main specification of olivine ore/concentrate for those areas
together with the chemical specifications.
Objective: This flotation study was conducted in natural pH condition with Na-oleate as
collector to clarify the effect of frother (MIBC) dosage on the LOI value of olivine concentrate.
Methods: Characterization of ore sample for this study was made by XRD, XRF and petrographic
analyses. Lizardite, a serpentine group mineral, was found to be a hydrated soft
fraction of ore sample in addition to hard olivine and pyroxene minerals constituting ore.
Results: Finely ground soft lizardite adversely affected the olivine flotation in a way of entraining
mechanically into concentrate. LOI value of concentrate was observed mainly to
be froth volume depended issue, and therefore, mainly water recovery dependent. LOI value
increased proportionally with water recovery at longer flotation time and MIBC dosages
indicating the entrainment of lizardite as the suspending hydrophilic component of water
phase. Certain rate of the hydrated lizardite mineral was thought to be recovered via hydrophobization,
which was clearly seen especially at the initial stages of flotation period in
the presence of excess frother. This experimental finding was attributed to similar chemical
composition of minerals constituting ore, and accidental activation of lizardite.
Conclusion: Lizardite recovery in froth was explained with accidental activation and/or
weak attachment of locked particles onto froth bubble although main recovery mechanism
was determined to be mechanical entrainment. Olivine concentrate obeying the specifications
of metallurgical applications could be obtained at suitable MIBC dosage and flotation