What Are Collectors?

In nature, most minerals are hydrophilic, meaning they have an affinity for water. Exceptions include minerals such as coal, graphite, talc, and molybdenite, which have naturally hydrophobic surfaces and inherent floatability. Gold minerals also typically exhibit hydrophilic characteristics. To alter the surface properties of mineral particles from hydrophilic to hydrophobic, thereby enabling them to attach to air bubbles and float, a specific type of chemical reagent known as a "collector" is added.

Collectors are generally classified into two categories: polar collectors and non-polar collectors. Polar collectors consist of two functional parts: a polar group that interacts with the mineral surface, and a non-polar group that imparts hydrophobicity. When these collectors adsorb onto the mineral surface, their molecules or ions orient themselves in a specific arrangement: the polar group attaches to the mineral surface, while the non-polar group extends outward, forming a hydrophobic layer. This transformation allows the mineral particles to become floatable.

For gold associated with sulfide minerals such as copper, lead, zinc, and iron, organic thio-compounds are commonly used as collectors in flotation processes. Examples include:

• Alkyl (ethyl, propyl, butyl, amyl, etc.) dithiocarbonates of sodium or potassium, commonly known as xanthates. For instance, sodium ethyl xanthate (NaS₂C·OCH₂·CH₃) is widely applied. In the flotation of polymetallic ores containing gold, ethyl xanthate and butyl xanthate are frequently employed.

  
  

• Alkyl dithiophosphates or their salts, such as (RO)₂PSSH, where R represents an alkyl group. These compounds are commonly referred to as aerofloats or dithiophosphates.

These collectors play a crucial role in the effective separation and recovery of gold and other valuable minerals during froth flotation, enhancing both efficiency and selectivity in mineral processing.