| 摘要 |
<p>A slurry (3) of ground calcite ore in water is subjected to a froth flotation (30) wherein acid insoluble impurities are removed. The flotation process is enhanced by a two-stage preflotation conditioning accomplished by adding an acetate salt of a tall oil based imidazoline (5) to the slurry (3) and then mixing a nonpolar hydrocarbon oil (7) into the imidazoline treated slurry. The purified underflow calcium carbonate slurry (11) from the froth flotation is first dewatered to a solids content of 80% to 90% by weight, then reslurried with a dispersing agent (40) and subjected at a solids content of at least 75% by weight to a multi-stage media grinding process (60, 70, 80) wherein each grinding stage is charged with progressively finer grinding media. After degritting, the ground calcium carbonate slurry (17) is ready for shipment as a paper filler-grade product slurry (19) without further dewatering. Alternatively, the product slurry (19) may be passed through an additional fine media grinding stage (100) to produce a paper coating-grade product slurry (21) also ready for shipment without further dewatering.</p> |
