METHOD AND INSTALLATION FOR CONCENTRATING HEAVY METALS, PRECIOUS METALS OR HEAVY MINERALS IN SAND OR GRAVEL

摘要

ABSTRACTThe invention relates to a method for concentrating preciousmetals and heavy minerals in sand or gravel deposits and an apparatusfor carrying out the method. The method comprises pre-classifyingthe raw material suspended as a slurry in water by means of screenmeans into two to six fractions. Each fraction as a slurry inwater is provided with a flow velocity of about 0.25 to about 0.50m/sec. over a length of about 3 m. The flow is retarded and stoppedto provide a plurality of volumes separated from each other in thedirection of flow in the lower range of the overall height of thefluidized bid. Each flowing volume is treated during the retardedflow condition in its lower range of height be means of thrust andsuction shocks acting on the flowing volume from below. Theapparatus of the invention provides in a raw material feed stationa vibrating feeder trough which is sidewardly open at its dischargeend for the conveying and disintegrating of agglomerated bulkmaterial. The sidewalls of the trough have inwardly bent upperedges so to partially extend over the conveying bottom. Nozzlesfor pressurized air or water jets are provided at the lower sideof the said bent upper edges. The feeder trough has associatedbehind it a forescreen for separating the deads and a collectingtank beneath said forescreen for collecting the produced slurry.