Study on preparation of amorphous nano-silica from coal gangue

Nano-sized amorphous silica was prepared using a gas-liquid phase method. Coal gangue, sulphuric acid with 98% in mass and calcium fluoride were used as starting materials. The phase, chemical structural characteristic and the morphology of production were investigated by infrared spectrophotometry, XRD and TEM, respectively. The main effect facts of production yield was systematically discussed. Results show that the maximum production yield of achive 17.9wt%, when the mass of coal gangue and CaF₂ is 3.00g and 8.00g, the volume of sulphuric acid with 98% in mass is 23ml and the optimized reaction conditions are the reaction temperature of 85°C, the reaction time of 2h, the particle size of coal gangue of about 200 mesh. the production exhibits the characteristic of amorphous silica dioxide of molecular structure. The morphology of amorphous silica dioxide exhibits flake with thichness size 50-100 nm under TEM.