Beneficiación de minerales densos en las playas de Galicia Nuevas Técnicas y Dispositivos

The industrial separation of heavy minerals in beach sands of Galicia using several newly developed devices is described. Preconcentration is achieved by a new type of centrifugal hydroclassifier with adjustable slope of the various revolutions of a flexible spiral, and remarkably well by an ”autopulsating hydroclassifier”, which treats up to 3 tons of ill-sorted material per hour with a recuperation of up to 90 % in an apparatus weighing 40 kg and driven by a current of (sea)water with a pressure of 1 atm. Electrostatic separation into conductive and isolating minerals was made more selective by using a high-tension generator equipped with an oscillator of variable frequency and by installing a generator of radiation with controlled wave-length between inducing and deflecting electrodes in the electrostatic separator. In this way it is possible, e.g., to separate zircon from quartz. Magnetic separation was improved by the development of a ”magnetic vibroclassifier” in which the grains are transported on a vibrating metallic plate through a magnetic field generated between a stationnary electromagnet and a rotating disc. Two flow sheets are given, the first for the treatment of material rich in magnetite and the second for the concentration of zircon.