In our country 80% of the gold ore dressing plants take the flotation method to extract gold, with the concentrate output mostly sent to the nonferrous smelting plants to process. Flotation technique has a great improvement over years and plays an important part in the process of gold separation.
At present, for chemical separation method, a majority of gold ore dressing plants make use of the amalgamation process and cyanidation process to extract gold. The amalgamation process is a kind of ancient gold extraction process, both simple and convenient, and economical, suitable for recycling coarse monomer gold, but it has a heavy pollution to the environment. Therefore, this method is gradually replaced by gravity separation, flotation, and cyanidation process.
The cyanidation process has several basic procedures including cyanidation leaching, washing and filtering of the leaching pulp, gold extraction from the cyanating solution or cyanidation pulp and smelting of the finished product.
Smelting is the last procedure to extract gold. It can be divided into primary smelting and refining smelting. Gold smelting has got swift and violent progress in our country, mostly using the traditional crucible melting to produce rough gold or send to the non-ferrous metal smelting plants to refined to be finished gold.
The low-grade oxidized ores in our country's mineral resources occupies a certain proportion. When dealing with such kinds of ores, it is uneconomical to choose the conventional cyanidation leaching method, while the dump leaching method may create more economic benefits.