Magnetoflotation of nickel ore

The nickel ores of Sudbury contain substantial amounts of the gangue minera l pyrrhotite (Fe8S9) which causes certain difficulties in The milling of th ese ores. This paper proposes a process called "magnetoflotation" as an eff ective means of dealing with pyrrhotite. The method reduces the pyrrhotite content of concentrates by applying a magnetic field on the froth product a s it leaves the flotation cell. Successful performance of magnetoflotation requires the optimization of sev eral variables. In this study, three of the variables (frother concentratio n, collector concentration, air flowrate) were investigated by Box-Wilson e xperimental design, and others (magnet speed, grind size, pulp density, flo tation time) were examined individually. The process was tested on a Falcon bridge nickel ore, assaying 1.92% Ni, and under the best operating conditio ns, a concentrate was obtained with 13.56% Ni grade and 74.32% recovery in a single step. Further improvements to grade and recovery were possible by cleaning and scavenging. The same ore was also tested with conventional met hods for comparison, and results indicated that magnetoflotation performed better.