Cyanidation of Whole Ore for Gold Extraction

Cyanidation of whole ore is a highly efficient gold extraction process widely used in gold ore beneficiation today. It offers advantages such as strong adaptability, high recovery rates, and a mature process, making it highly favored by gold processing plants. This process primarily consists of six core stages: crushing and screening, grinding and gravity separation, secondary classification, de-sliming and slurry adjustment, cyanide leaching, and desorption and electrolysis.

The raw ore is first coarsely crushed by a jaw crusher, then screened on a vibrating screen. Material meeting the required particle size is stored in a bin, while oversized material is sent to a cone crusher for further crushing, forming a closed-circuit crushing process that ensures a stable feed size for the grinding stage.

The grinding stage utilizes grid-type ball mills. To minimize waste from over-grinding, a combined jig and shaking table gravity separation process is employed after grinding to recover a portion of the coarse-grain gold in advance. The remaining slurry is sent to a desliming tank for washing, thereby improving the efficiency of subsequent operations.

After desliming, the slurry undergoes secondary classification via a hydrocyclone; the overflow proceeds to the next process, while the underflow is returned to the ball mill for regrinding, achieving a closed-circuit grinding process and ensuring thorough mineral liberation.

After the slurry is screened to remove impurities such as wood chips, it is adjusted in a thickener to maintain a concentration of 35%–38% and a pH of 10–11, creating optimal conditions for cyanide leaching.

Cyanide leaching employs a “pre-leaching + counter-current activated carbon adsorption” process. The slurry is first pre-leached in a leaching tank, where cyanide concentration, oxygen levels, and bubble dispersion are controlled. It then passes through a series of connected tanks to achieve simultaneous leaching and adsorption, maximizing the dissolution and adsorption of gold.

Finally, the gold-loaded carbon is heated in a desorption column to desorb the gold, yielding a precious metal solution and desorbed carbon; the precious metal solution is electrolyzed to produce gold slime, and the desorbed carbon is regenerated for reuse. The entire process is continuous and stable, with a high gold recovery rate.