Gold tailings refer to the waste residues of primary gold mines after beneficiation. With the continuous development of beneficiation technology, it has been found that many gold tailings still can be recovered. So what are the commonly used gold tailings recovery technologies?
Widely used in the separation of fine and very fine materials, flotation has been gradually applied to the recovery of gold from gold tailings in recent years.
In the gold tailings reselection process, the flotation method is mostly suitable for gold-bearing mineral tailings with good floatability. Generally, regrinding is required to ensure the full dissociation of gold-bearing minerals before flotation. Adopting flotation process to reconcentrate gold tailings can achieve efficient dispersion and inhibition of gangue minerals.
Usually, the gold tailings are first reground to -200 mesh which accounts for about 70-80%, then are sent to roughing, beneficiation and sweeping to obtain qualified gold ore concentrate with series of single or combined collectors (butyl xanthate, butyl ammonium black drug, isopentyl xanthate, Y89 xanthate), activator (copper sulfate), pH adjuster (sulfuric acid), etc.
When it is difficult to recover gold in tailings by conventional flotation method, cyanide leaching method can be considered. This method is suitable for gold-bearing mineral tailings with finer particle size and better dissociation.
The gold-bearing ore is leached in the cyanide solution, and then activated carbon is used to directly absorb the dissolved gold from the pulp, and the gold-loaded carbon is desorbed and the electrowinning gold mud is directly separated, purified and smelted. In addition, the low-cost heap leaching process can also be used according to the actual situation, and the tailings can be granulated by heap leaching or non-granulated chemical loose heap leaching.
The above has introduced two technologies for gold tailings reconcentration and recovery of gold. The grade of gold in some stockpiled tailings found so far is above 0.5g/t, which indicates great potential for gold recovery.
In addition, there are copper, iron, lead, zinc, quartz, feldspar and other substances in the gold tailings. If you want to determine the content of each mineral, you’d better carry out a beneficiation test. When the value of re-separation is confirmed, you can invest into the reconcentration of gold tailings.
