Combustion of rice husks to low-carbon silica and synthesis gas - by a slow heating process

摘要

Combustion of rise husk waste, with or without utilisation of the heat produced, comprises (a) pretreatment with dil. mineral acdi to extract furfurol by known methods, (b) gasification in absence of air to obtain synthesis gas (H2 + CO) and (c) slow combustion and/or gasification of the remaining coke. In alternative processes, (A) and/or (b) may be omitted. Used for prepn. of high purity silica for mixing with refractory materials. All constituents of the waste material are utilised as furfurol, gas, ash and heat. Pollution of the environment by burning is avoided and heat requirements are supplied by the waste itself. White silica with low content is obtd. The process can be varied to match the requirements for heat and/or gas.