水溶液中における重晶石, 方解石, 灰重石の界面性状と浮遊性

抄録

In barite-water system, the concentrations of constituent ions of the mineral are kept constant over a wide pH range of aqueous solution except strong acidic and alkaline sides. When an equivalencepoint (EP) is defined as the condition at which any selected pair of positive and negative ions have equivalent concentrations, EP (BaOH⁺, HSO^-₄) was pH 7. 6. The EP coincides with IEP (aq) which denotes the condition at zero point of total electric charge of chemical species concerning constituent ions of the mineral. Hydrolysis of surface barium or sulfate ionic species on barite is regulated in accordance with the degree of deviation of pH value from the EP. Flotation behaviour of barite with DAA depended upon the surface hydrolysis. Floatability of barite with SDS was very good over a wide pH range and was not affected by the surface hydrolysis. Consequently, the adsorption mechanism of SDS must be chemical, and that was confirmed by the solubilityproduct of barium dodecyl sulfate.
In calcite-water system, the concentrations of chemical species concerning constituent ions of the mineral are remarkably affected by pH valueof aqueous solution. In this case, surface calcium or carbonate ionic species hydrolyze inaccordance with the degree of deviation of pH value from the IEP (aq). The floatability of calcite with DAA and SDS was affected by the surface hydrolysis. An IEP (aq) of calcite-water system is affected by P_CO2 of gas phase in contact with the system, and also, the system is needed long time for attaining to equilibrium with atmosphere, (P_CO2= 10^-3.5a tm). An IEP (aq) of the system shows a pH value between pH 10.00 and pH 8.35 through the process attaining to the equilibrium. Thus results of measurements of i. e. p.would vary with experimental conditions and methods of measurement etc.
Flotation behaviour of scheelite with DAA and SDS as a function of pH value was closely related to variation of the zeta potential.