The standard flotation reagent for fluorite is a pure oleic acid or a very high grade of tall oil fatty acid such as AERO 704 promoter, with such modifying agents as sodium carbonate, sodium silicate, starch, and quebracho, or tannin if carbonates are present. Many operations need to heat the conditioned pulp, especially in the cleaning circuits to achieve the desired selectivity, recovery, and reagent economy.
In most standard practices, the ore is conditioned with 500 to 2500 grams per tonne of sodium carbonate, (depending on the water hardness), 50 to 500 grams per tonne of quebracho, followed by the addition of AERO 704 promoter at a dosage of 500 to 1000 grams per tonne. In most cases, the addition of a heavy oil such as Number 5 fuel oil, is used as a froth control agent.
AERO 845 promoter has shown promise in the laboratory and in the plant, as a partial (and occasionally total) substitute for oleic and fatty acids. One of the main advantages indicated is the possible reduction of the temperature required in the cleaning stages since AERO 845 promoter is water soluble and more selective than fatty acids.
If AERO 845 promoter is being used alone, the previously described standard practice is followed, with the exception that the AERO 845 promoter is applied by stage-addition with a recommended dosage of 100 to 500 grams per tonne. In cases where AERO 845 promoter does not give satisfactory recovery when used alone, it should be tested as a 10% to 20% replacement for the fatty acid.
ACCO-PHOS 950 depressant, at dosages of 20-100 g/t with conditioning prior to conditioning with AERO 704 promoter has recently demonstrated effective depression of P2O5 to improve fluorite concentrate grades.