The practical and effective pulp distributor here presented is believed to be of a completely new and innovative design. It was developed at the San Nicolas Plant of the Marcona Mining Company in Peru, where it has been thoroughly plant tested using iron ore slurries of a particularly abrasive nature.
As indicated, the motivation for development was simple necessity. The plant in San Nicolas crushes, grinds, and concentrates magnetic iron ores of a particularly abrasive nature, and depends largely on magnetic separation to obtain a marketable product. Feed to the numerous drum magnetic cobbers and finishers varies from rod mill discharge at a nominal minus ten mesh to a ball mill fine grind of seventy percent minus three hundred and twenty-five mesh.
Analysis of the action taking place in either type of the apparatus originally installed shows that the distributional effects depended on the flow of a pulp stream which was expected to behave as though it had the fluidity of water. The ore particles are of a specific gravity of five, and would immediately settle out when the flow velocity slowed to less than a critical speed.
It was apparent that a more positive type of action would be necessary to overcome the effects of rapid settling of the heavy ore particles. A number of modifications on the basic types were proposed and tested with no appreciable improvements. A check of mechanisms on the market was made with negative results.
A satisfactory unit was developed using a few feet of the slurry head for initial force, with a rapid flow directed in a fan-shaped layer out from central cylindrical tank. The stream velocity was ample to carry the solids in suspension across a few feet of platform to the receiving process unit. At this time only the specific problem of feeding magnetic separators will be considered, although the apparatus is equally adaptable to other machines, such as screens.
As the poor distribution had become a major source of concern to the operators, the problem was kept constantly in mind. This may account for the unusual source of the basic idea; namely, a pictorial representation of the topological concept known as a Klein Bottle. Further, if the opening consisted of a row of slots around the curvature of the bottle, incremental portions of the stream would leave by each slot in a direction approximately perpendicular to the tangent of the curve at that point. A fan-shaped sheet of liquid would result, which would become proportionately wider with increased distance from the center.