A Method of High-quality Silica Preparation from Copper Smelting Slag

High-quality silica was prepared from copper smelting slag through a method of in situ modification. The effects of the addition of an amount of polyethylene glycol-6000 as a modifier, the modification temperature and the modified endpoint pH on the particle size and specific surface area of the silica were systematically studied. It has been shown that the particle size, specific surface area, and the interstices between the particles were greatly affected by the modification temperature and the pH of the modification endpoint. Optimal conditions are: modifier 10% as solute mass, modification temperature 40°C, and pH of modification endpoint 8.5. Under these conditions, the silicon sinking rate was as high as 97.82%, the prepared silica particles had good dispersibility, the average particle size was 20 nm, the particle morphology was spherical, and the specific surface area was as high as 244.67 m2/g, which was superior to A-grade standard of HG/T3061-1999 and ISO 5794-1:2005(E), and could be directly used in the rubber industry.