Gold Processing Plant

Flotation process are widely used for improving the sulfide type gold ore grade. The ore pulp slurry is pumped to flotation cells for extracting. The flotation cells are divided into several parts: roughing, concentration and scavenging (the exact numbers of stages for each part should be decided by test work to reach the best recovery), and with the use of frothing agent and collecting agent, the gold concentrate will be collected. The flotation concentrates can be sold to the smelting factory based on normal trade or processing agreement. The flotation concentrates go to cyanide process or calcination process (if there is arsenic together with the concentrate) and further process to get pure gold in the smelting factory. During this process, the silver & copper can also be collected.

CIL is mainly for processing the oxide type gold ore if the recovery rate is not high or much gold is still left by using flotation and/ or gravity circuits. Slurry, containing uncovered gold from primary circuits, is pumped directly to the thickener to adjust the slurry density. Then it is pumped to leaching plant and dissolved in aerated sodium cyanide solution. The solubilized gold is simultaneously adsorbed directly into coarse granules of activated carbon, and it is called Carbon-In-Leaching process (CIL).

Heap leaching is always the first choice to process low grade ore easy to leaching. Based on the leaching test, the gold ore will be crushed to the determined particle size and then sent to the dump area. If the content of clay and solid is high, to improve the leaching efficiency, the agglomeration shall be considered. By using the cement, lime and cyanide solution, the small particles would be stuck to big lumps. It makes the cyanide solution much easier penetrating and heap more stable. After sufficient leaching, the pregnant solution will be pumped to the carbon adsorption column for catching the free gold. The barren liquid will be pumped to the cyanide solution pond for recycle usage.

The loaded carbon is treated at high temperature to elute the adsorbed gold into the solution once again. The gold-rich eluate is fed into an electrowinning circuit where gold and other metals are plated onto cathodes of steel wool. The loaded steel wool is pretreated by calcination before mixing with fluxes and melting. Finally, the melt is poured into a cascade of molds where gold is separated from the slag to gold bullion.