Effect of thermal stability on the flotation response of sodium carbonate salts

Laboratory microflotation experiments show that flotation of certain sodium carbonate salts with cationic and anionic collectors is possible if the salts are thermodynamically stable under the prevailing experimental conditions. Sodium carbonate monohydrate can be floated up to 100% recovery with cationic dodecyl amine hydrochloride (DAH) and anionic sodium dodecyl sulfate (SDS) collectors at temperatures above 40 °C. Sodium carbonate decahydrate floats to a maximum yield of about 30% with 1×10⁻³ M DAH and to 17% with 1×10⁻⁴ M SDS even at room temperature where it is thermodynamically stable. Trona, the double salt of sodium carbonate and bicarbonate, does not float at room temperature in its saturated solution with either collector. Complete flotation of sodium bicarbonate in its saturated solution at pH 8.3 occurs with both DAH and SDS at all temperatures. Complementary data on flotation, viscosity and FTIR studies reveal that in addition to the thermal stability, the flotation response is dictated by the relative contributions of viscosity and water structuring properties of soluble carbonate salts.