Counter Current Decantation Cyanide Gold Leaching

The Process Flowsheet CCD CY-1 shows (below) the continuous counter-current decantation system, in which all the ore is first reduced to a very fine state in the grinding mill-classifier circuit, in a cyanide solution. The slime overflow of the classifier, usually 70%—200 mesh, or finer, is sent to the first thickener, known as the primary thickener. Here the pregnant solution, containing a large part of the dissolved gold and silver values, overflows from the top of the thickener and is sent to a clarifier. then to the precipitating system where the gold and silver values are precipitated, the precipitate periodically being reduced to bullion in a furnace. The underflow pulp of the primary thickener, containing the remaining values and usually at a pulp ratio of 1:1, is elevated by a diaphragm pump into a series of agitators. The agitators are used to aid in the dissolution of the remaining values, augmented by the introduction of air. The time of treatment required depends upon the values still remaining in the slimes or fine sands in the mill pulps. From the agitators, the pulp at a density of approximately 1:1 overflows directly into the first of a series of secondary thickeners. This feed pulp … Continue reading Counter Current Decantation Cyanide Gold Leaching