Carbothermal reduction of beach sand to graphite silicate and silicon carbide

Silicon carbide has very specific application scope in the field of energy storage device fabrication. In this paper we have attempted a cost effective, energy saving single step method to fabricate graphite silicate (SiO₂C) and silicon carbide (SiC) from beach sand. Carbothermal reduction of sand by microwave heating was found successful to produce SiO₂C/SiC at 800°C. Nano sheets of graphite silicate and nanorods of SiC were formed at 800°C when heated for 60 minutes. When the heating time was increased to 120 min, formation of such nanosheets was abundant. But when the time was further increased to 180 min, agglomeration as well as compacting of the nano sheets was seen. But microwave heating to 480 min at 800°C showed completely sintered irregular particles of SiO₂C/SiC in the product. Experiments were conducted using a mixture of carbon, sand and highly excess quantity of NaCl. The exorbitant amount of heat generated during the carbothermal reduction of sand was allowed to dissipate in the excess NaCl and the sintering effect was minimized. In this reaction, formation of pure SiC nano rods/thin long sheets was seen. The temperature suitable for preparation of graphite silicate/SiC was found to be 800°C with a soaking time of 60 to 120 min.