PQ Silicates are inorganic water-based solutions of silica. These products feature large concentrations of dissolved alkali and silicate polymers. Silicate acts as a depressant for minerals such as calcite, fluorite, barite and quartz. In flotation operations, sodium silicate keeps the undesirable gangue particles in the water phase while the desirable value particles are carried to the surface by air bubbles. A silicate dosage of 1-5 kilogram per ton of ore is required for this application.
Silicate also serves to disperse and aid grinding again due to the dissolved anionic silicate polymers. Silicates provide more efficient separation of the value from the gangue, leading to higher grade and improved recovery. Dosage must be determined experimentally but may be on the order of 0.05-0.5 kilogram per ton ore.