| Silica powder, which is usually called white carbon black, is a kind of very excellent functional inorganic powder materials. It is widely used in rubber, dope industry, printing ink, plastic, foodstuff, toothpaste and other industries. Now the sulfuric acid precipitation is the primary method to produce silica powder around the world, and the domestic corporations mostly adopt traditional producing technology with a series of disadvantages like high consuming cost, low single producing capacity, rigorous operating condition, long reacting time, big particle size and small reactors which are not suitable to be magnified. The high gravity sulfuric acid precipitation method to prepare silica is a new technology with simple process, short reacting time, easy operation and industrialization.In order to make the high gravity sulfuric acid precipitation method be continuous, in the paper the rotating packed bed's main parts are reconstructed, the technological process is designed, and then the continuous experiment is studied.The mass fraction of sulfuric acid, the rotor speed of RPB, flow rate of silicate sodium and the concentration of sodium silica change in this experiment to investigate the effect on the quality of silica powder and the producing capacity. The results indicate as follow: Along with the mass fraction of sulfuric acid increasing, the average particle size of silica is less than 10 nm, the specific surface area and the producing capacity firstly increase, then decrease, finally increase again, but the DBP absorption value changes by contraries with them. Except the concentration of sodium silicat is 10 %, other concentrations all make the process appear gelatin. When the mass fraction of sulfuric acid is 25%, and the concentration of sodium silicat is 10%, the producing capacity is the most. With the increasing of rotor speed, BET decrease at first and then increase, the tendency of DBP is decrease; effect of silicate sodium flow rate on the BET is not significant. The DBP is relatively small and that is mainly because of the inappropriate drying method.Continuous experiment of silica powder's production with sulfuric acid precipitation method in RPB is conducted. The production is small in diameter and has large specific surface area. It lays foundation for industry production of silica powder. |
