How to flotate vein gold and silver ore?

Foam flotation is a method of separating minerals based on their physical and chemical properties. Classified by floatability, gold and silver minerals belong to the first category of natural non-ferrous heavy metal sulfides, which are characterized by low surface wettability and easy flotation, and can be flotated with xanthate collectors. 

The froth flotation method is widely used to process various vein gold and silver ores for the following reasons:

(1) In most cases, the froth flotation process can maximize the enrichment of gold and silver in sulfide concentrates and discard large amounts of gold and silver ore tailings, thereby reducing smelting costs.

(2) For refractory gold and silver ores that cannot be directly treated by amalgamation or cyanidation, a combined process including flotation is required. However, flotation also has some limitations. For example, ores with gold particles larger than 0.2-0.3 mm or pure quartz gold ores without metal sulfides are difficult to process through flotation separation alone.

Gold and silver ore foam flotation method

The froth flotation method is usually based on the properties of gold and silver ores and product specifications. The common principles and processes are as follows:

Froth flotation + flotation concentrate cyanidation

A small amount of concentrate is obtained by flotation from gold, silver and quartz veins, and then the cyanidation process is carried out. Compared with the all-sludge cyanidation process, the foam flotation concentrate process has the advantages of not requiring fine grinding of all ores, saving power consumption, small plant area, and low infrastructure investment.

Froth flotation + concentrate roasting + calcination cyanidation

This process is often used to treat insoluble gold-arsenic ore, gold-antimony ore, and gold-pyrite ore with high sulfide content. Roasting removes elements arsenic and antimony that are harmful to the cyanidation process.

Flotation cyanidation + flotation ore concentration + flotation concentrate and then roasting

This foam flotation method is used to process quartz sulfide ore or pyrite containing gold and silver, pyrrhotite containing gold telluride, pyrrhotite, chalcopyrite and other sulfide minerals. The floatable gold telluride in the ore is first produced in the form of concentrate, and then roasted and cyanided to expose the gold and silver ores to sulfide and telluride. Since the mid-tailings after flotation generally contain high gold content, they need to be recovered through cyanidation.