What is the function of collectors in the froth floatation process for the concentration of ores?

A collector is a chemical substance which is due in the process of froth floatation for the concentration of ores (like Sulphide) due to its property of non-wettability. This helps in the purification of ores.

For instance, Pine oil is used in the purification of sulphide ores, it attracts dust particles easily which thereby can be removed using water.