The flotation of mineral ores is a process that has been refined for more than 120 years. Since the early 1990's BOC has investigated the use of gases such as oxygen, nitrogen and CO₂, in the mineral processing industry. The application of our gases changes the hydrophobicity and hydrophilicity of the surface characteristics of the ore particles. Careful optimisation of this characteristic which can be measured by dissolved oxygen concentration, Eh and pH of the mineral slurry, can lead to gains in either grade or recovery of a concentrate.

Each of these three gases (oxygen, nitrogen and CO₂) will have a different effect on a customer's process which is best validated by a trial on the customer’s equipment. In general:

• Oxygen promotes galvanic interactions. It increases the dissolved oxygen concentration, which will increase the Eh of a slurry, that can lead to an increase in flotation of minerals like sulphides of copper, gold, lead, nickel and zinc.
• Nitrogen is used to decrease the dissolved oxygen concentration. This will reduce the mineral surface hydration and will decrease the Eh of a slurry. This can lead to an optimisation of collector reagents used in the molybdenum or copper flotation, improving grade/recovery or reducing reagent usage. 
• Carbon Dioxide is used to lower the pH of the slurry. The modification of the pH can lead to changes in the efficacy of flotation circuit chemicals, leading to the potential of reagent savings.