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Gold recovery methods mainly include gravity separation method, flotation method, amalgamation method, cyanide method and resin in pulp method. And the combined gold recovery methods are often used to extract the gold from vein type gold ore.
Here are the 9 common gold recovery methods for vein type gold ore extraction:
Single amalgamation method
Amalgamation-gravity separation combined method
Gravity separation (amalgamation)- cyanide method
Single flotation method
Amalgamation-flotation method
All-slime cyanidation method
Flotation-cyanidation method
Flotation-gravity separation method
Heap leaching method
This process is suitable to treat the coarse-grained gold contained quartz vein primary gold deposits and oxidized ores containing. Amalgamated gold recovery is an ancient and universal method for gold extraction. Since the gold is mostly free in ores, some gold grains in all ores can be recovered by amalgamation. It has been proved that using the amalgamation method to recover some gold particles in advance can obviously reduce the loss of coarse gold in tailings.
This kind of gold recovery method is divided into two schemes: Amalgamation first and then gravity separation, gravity separation first and then amalgamation. Amalgamation first and then gravity separation method is suitable for treating simple quartz vein type gold bearing ores. Gravity separation first and then amalgamation method is suitable for treating the gold ores with large gold grains but is polluted and recovered by the oxidation film, not easily mixed with mercury, and the ores with low gold content.
This kind of gold recovery method is suitable for treating quartz vein type oxidized gold ore. First, the raw ore is separated by the gravity separation method, and the concentrate obtained by the gravity separation is sent to amalgamation. Or the raw ore can be treated with the amalgamation directly, and the tailings, grading ore and mixed sand can be cyanicated separately.
This kind of gold recovery process is suitable for the treatment of quartz vein ore with fine gold particles, high floatability of sulfide, polymetallic gold-bearing sulfide ore and carbon- (graphite) containing gold ore.
This process is to first use amalgamation to recover the coarse gold in the ore, and the amalgamation tailings is treated with flotation. This process is suitable for the treatment of gold ore after the single flotation method, gold-bearing oxidized ore and associated free gold ore. And this process can obtain higher gold recovery rate than the single flotation method.
Gold is produced in quartz vein ore in the form of fine or micro-fine dispersion. The ore is highly oxidized and does not contain Cu, As, Sb, Bi or carbon. This kind of gold ore is best suited to all-slime cyanidation method.
Cyanidation is one of the main recovery methods to extract gold and silver. Gold recovery with this method has the advantages of high recovery rate, strong adaptability to ore and property gold.
Gold recovery by cyanidation consists of four main steps: leaching of gold ore in cyanidation solution, separation of gold liquor and leaching residue, precipitation of gold leaching and smelting of gold mud. The disadvantage of this gold recovery method is that cyanide is a highly toxic substance and easily pollutes the environment.
Flotation- concentrate cyanidation process. It is suitable for treating quartz vein gold bearing ore and quartz pyrite ore which are closely related to gold and sulfide.
Flotation-roasting-cyanidation process. The process is suitable for dealing with minerals that contain floatability and are harmful to cyanidation, with which only a small amount of gold is bound.
This gold recovery process is focused on flotation method, which is suitable for ores with close co-existence between gold and sulfide and can only be recovered by smelting. It is also suitable for gold bearing quartz vein ores with uneven coarse intercalation, which can obtain higher gold recovery rate than single flotation method.
Heap leaching is a type of cyanidation method for gold recovery, which is often used to treat the gold ore with low grade. This method has simple process, low investment and low cost.
The above 9 gold recovery methods are the common gold extraction processes. The selection of gold recovery processes shall be different according to the type and nature of the gold ore being processed. It is suggested to do professional mineral dressing test to design a suitable solution for your mine before into production.
Summary of Gold Cyanidation Methods