Apparatus for continual magnetisation of a slurry

#The present invention relates to the field of mineral processing and, more particularly, to methods and apparatus for enhancing the efficiency of magnetising a slurry for the extraction of minerals from a flowstream.

#1. Mineral Separation

#Many important metal ores are sulfides. Significant examples include; argentite (silver sulfide), galena (lead sulfide), molybdenite (molybdenum sulfide), pentlandite (nickel sulfide]), realgar (arsenic sulfide), and stibnite (antimony), sphalerite (zinc sulfide), and pyrite (iron disulfide), and chalcopyrite and bornite (iron-copper sulfide). Vaughan, D. J. Craig, J. R. 1978

#Embodiments of the present invention will now be described with reference to the accompanying drawings wherein:

#FIGS. 1A and 1B illustrate the effect of equipment sizing on using wiper magnetising according to a first-preferred embodiment of the present invention.

#FIG. 2 illustrates the slurry magnetising equipment according to a preferred embodiment of the invention.

#It has been discovered that magnetizing a flotation slurry that contains a number of paramagnetic minerals can result in not only the increase in recovery of some paramagnetic minerals that are actively collected but also the reduction in recovery of other paramagnetic minerals that are recovered by entrainment. This is a surprising result. It was thought that there would be heteroaggregation of all the paramagnetic minerals, but what has been discovered is that there is primarily homoaggregation of the paramagnetic minerals. However, in flotation some fine mineral is recovered not by being actively floated but by being entrained in the froth. This is a well recognized phenomenon. Entrainment is most pronounced for fine minerals and generally increases with the fineness of the minerals. Therefore, if the mineral can be aggregated then its particle size will increase and there will be less entrainment of these mineral in the froth, if the plant is not actively trying to float them.

#For example, in a recent investigation in a plant the slurry contained the paramagnetic sulfides chalcopyrite and sphalerite. The process operates to produce a chalcopyrite concentrate first and then subsequently a sphalerite concentrate. When magnetic conditioning was applied to the chalcopyrite slurry the chalcopyrite recovery increased (less copper in the tailings from the process) but the recovery of the sphalerite in the chalcopyrite concentrate actually declined.

#% Cu % Cu in % Zn Recovery in % Zn Recovery in Rec Tailings Cu Concentrate Zn Concentrate Magnetic 84.5 0.5 7.41 79.7 Conditioning ON Magnetic 84.0 0.54 7.96 77.9 Conditioning OFF