Enhancement of calcium dissolution from steel slag by ultrasound

When calcium bearing phases liberate their calcium, the remaining silica and other common impurity species in the slag form a porous layer on top of the calcium-liberating surface. This porous layer and in some cases, mechanically weak surface can be removed effectively by sonication. Hence, 96% of the calcium in the smallest particles (50-74 μm) of the slag was extracted by ultrasonic, and 65% by mechanical agitation. While from the largest particles (500-1000 μm), 38% of the calcium were extracted by ultrasonic and 18% by mechanical agitation. Thus, sonication significantly enhances the extraction of calcium from both small and large particles.