Dry raw rice husks (RHs) were sieved to eliminate residual rice
and clay particles. After thorough washing with deionized water,
the RHs were filtered and air-dried at room temperature. A sample
of rice husk was converted into rice husk ash by heat-treating rice
husk at 900 8C for 4 h. After washing with deionized water and
filtration, the RHA was dried at 120 8C for 16 h. Results show that
highly active solid catalyst can be obtained by mixing and well
grinding 1.00 g RHS with 1.23 g Li2CO3 calcined at 900 8C in air for
4 h.