Processing Line for Slab-grade Silica Sand with Acid Leaching

Crushing： The raw ore first passes through a buffer silo (including a screen for removing impurities) and is then fed via a feeder to a cone crusher for crushing to a particle size range of 5mm-30mm.

Pre-screening： After crushing, the ore enters a pre-screen. Material larger than 30mm is screened out and returned to the cone crusher for further crushing. The remaining material enters a spiral ore washer for pre-washing to reduce mud content.

Color Sorting： The pre-washed ore passes through a vibrating screen to separate fine material smaller than 5mm. Material between 5-30mm enters a color sorter for debris separation.

Grinding： The qualified material after color sorting is fed into a ball mill for sand production. After grinding, it passes through a post-grinding screen in a closed-circuit process. The undersize material enters a scrubber for a powerful scrubbing process to effectively remove surface iron, aluminum, and colloidal impurities.

Desliming： After scrubbing, the ore is pumped into the desliming hopper on the grading tower for initial desliming. It then enters the thickening hopper to reduce the pulp concentration. The ore is then sent to the hindered settler to separate the coarse material larger than 26 mesh. This material is then returned to the ball mill via a return conveyor for re-grinding. A safety screen is installed throughout this process to improve classification efficiency and fine material recovery. Fine material below 26 mesh enters the hydraulic classifier to separate the product below 140 mesh.

Magnetic Separation： Qualified ore is sequentially passed through a medium-magnetic plate magnetic separator (4000-4500 GS) to remove mechanical iron, followed by a high-magnetic plate magnetic separator (11000-12000 GS) to remove all mechanical iron and some weakly magnetic iron. It then passes through two series-connected vertical ring high-gradient magnetic separators (1.5T magnetic field) for electromagnetic iron removal. The deslimed product is concentrated in the thickening hopper, dewatered on a dewatering screen to reduce moisture, and conveyed by belt to a water control area for temporary storage, ready for the next process.

Pickling： The finished sand is conveyed from the silo to a PP pickling reactor, where it reacts with an environmentally friendly acid at 70-80°C for 6-8 hours. After the reaction, the acid is pumped into a hot acid circulation tank. The remaining 20% of the acid is squeezed out with clean water. The acid is then deacidified in a scrubber and removed by a clearing hopper. Afterwards, 0.5% industrial alkali is added to neutralize the sand to a pH of 6.5-7. The neutralized water is discharged into a tank. After being rinsed with clean water, the sand is dehydrated and transported to the finished product warehouse.