Separation of Oxidized Pyrrhotite from Fine Fraction Serpentine

Jian Zhou,Yiping Lu,Guozhi Mao

doi:10.3390/min8100472

Abstract

Abstract: The valuable minerals in copper-nickel sulfide ore can easily be oxidized, leading to the reduction of their flotation recovery and a difficulty in separating them from gangue. In order to solve the problem, the reaction mechanism of the octanohydroxamic acid (OHA) on oxidized pyrrhotite was revealed through micro-flotation, adsorption tests, zeta potential measurements, and X-ray photoelectron spectroscopy (XPS) analysis. The results show that this is a feasible way to find a suitable collector that can directly react to oxidation products on the surface of pyrrhotite. OHA can efficiently reclaim oxidized pyrrhotite and achieve the selective separation of a pyrrhotite-serpentine mixture in a weak alkaline environment. The adsorption tests, zeta potential measurements, and XPS analyses show that OHA can interact with an oxidized pyrrhotite surface, and the interaction between OHA and serpentine is very weak. The XPS analyses indicate that the OHA collector can chelate with Fe(OH)3 on the surface of oxidized pyrrhotite and form an “O, O” five-ring chelate. At the same time, the OHA collector may compete with the hydroxyl groups of hydrophilic substances on the mineral surface to produce hydrophobic products and reduce the hydrophilic substances on the mineral surface.

Highlights

Froth flotation, a widely-used treatment of base metal sulfides, relies on the differences in surface properties between sulfide minerals and non-sulfide minerals
A moderate surface oxidation of sulfide minerals is known to be beneficial for the adsorption of collectors and the formation of a hydrophobic surface, i.e., slight surface oxidation can increase the floatability of sulfide minerals [6]
OHAindicates on thethat surface-oxidized pyrrhotite was revealed through mechanism of on the surface-oxidized pyrrhotite was revealed through micro-flotation, adsorption tests, zeta potential measurements, and X-ray photoelectron spectroscopy (XPS) analyses

Summary

Introduction

A widely-used treatment of base metal sulfides, relies on the differences in surface properties between sulfide minerals and non-sulfide minerals. These differences become increasingly marginal as the sulfide mineral surface becomes oxidized [1,2,3,4]. A moderate surface oxidation of sulfide minerals is known to be beneficial for the adsorption of collectors and the formation of a hydrophobic surface, i.e., slight surface oxidation can increase the floatability of sulfide minerals [6]. Once sulfide minerals are heavily oxidized, the floatability of sulfide minerals decreases sharply, which may be mainly due to the formation of metal hydroxide species on the surface of sulfide minerals [12,13]. A collector cannot effectively collect the valuable sulfide minerals unless the dosage is significantly increased [1]

Methods

Results

Conclusion