A Carbon In Leach Gold Recovery Plant. This plant processes 4 million tons of ore per year with an average gold content of 0.043 ounces of gold per ton of ore. Approximately 85% of the gold is recovered in the plant. The crushed ore is fed to tanks of cyanide solution, where the gold is dissolved in the cyanide. The pregnant solution is then transferred to a series of tanks, where carbon is added. The gold is adsorbed onto the surface of the carbon. The carbon, with gold attached, is removed by screening. The gold bearing carbon is then introduced into a heated sodium hydroxide-cyanide-water solution where the gold is dissovled. This concentrated solution is passed through a series of electrowinning cells, where the gold quickly plates (in about 3 minutes) onto the stainless steel cathodes. The gold is washed from the cathodes, with high pressure sprays, dried and melted, to be poured into molds for gold bricks, or ingots. |
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A flowsheet, showing the Carbon In Leach (CIL) process
This circuit utilizes a thickener, to maintain a constant percent solids in the ore feed,
necessitating less water used in the process, smaller tanks and a smaller pond.
It also gives much more control over the process that a conventional CIL plant without a thickener.
The CIL process is viable if there is sufficient gold content, carbonates/clays in the ore which will
"rob" some gold in solution, and it leaches in 8-13 hours. |
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A Stainless Steel Cathode from the electrowinning cell in the
gold room. Notice the gold that has plated onto the surface of
the stainless steel mesh. The next step is to wash the gold from
the cathode with a high pressure water sprayer, then melt it and
pour it into a mold where it will be in a
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