Froth Types

There are many operations around the world treating silver-gold ores by froth flotation and the froth type is a very important parameter at the moment of making any change in the silver-gold flotation operation. These operations usually have a high content of silver respect to gold. For example, 250-300 g/t of Ag and 1-2 g/t of Au. Various research reports exist where several devices have been used in the analysis and classification of flotation froths. However, sometimes it is custom to mention a simple classification: big bubbles and small bubbles, and they do not necessarily match the experts’ opinion of what are the relevant phenomena.

Now, on the other hand, the bubble size and shape information may be used directly for determining the froth classes; these measures provide an indication of the operation. It must be recognized that process properties vary from plant to plant, and consequently there does not exist any universally applicable classification. Only the operators’ experience knows what is relevant in each case. For example, operations with high content of clays have a common problem, slimes, which make difficult to recognize the condition of the froth, but when there is not that problem, froth characteristics can be identified.

Froth characteristics are based on average bubble size, mineralization, color, bright and movement velocity of the froth. Next figures show the main froth types in silver-gold operations.

Main characteristics are shown in next table.