Synthesis and sintering of Li4SiO4 powder from rice husk ash by solution combustion method and its comparison with solid state method

• Li4SiO4 prepared by solution combustion method using rice husk ash as silica source.
• Phase pure, submicron size Li4SiO4 powders prepared at 650 °C.
• Li4SiO4 is also prepared by solid state method for comparison of different properties.
• Powder can be sintered at 900 °C with acceptable density and small grain size.
• Absence of closed pore achieved in sintered specimen.

Phase pure lithium orthosilicate (Li4SiO4) was prepared by the solution – combustion technique as well as solid state method using rice husk ash (RHA) as silica source. It was found that by controlling the metal to citrate ratio of the starting solution, phase pure powder can be prepared at 650 °C. Whereas in solid state method, calcination at 800 °C was required to achieve phase purity. The particle size of Li4SiO4 powder (prepared at C/M = 1.4) was found to be 100–200 nm with low surface area (1.83 m2/gm). It was found that Li4SiO4 powder can be sintered at a temperature as low as 900 °C with a density ∼83% of the theoretical density. In case of solid state method prepared powder, maximum 80% of the theoretical density could be achieved. Phase stability in the sintered sample was studied.

Preparation of white RHA and Li4SiO4 powders using solution combustion technique.Figure optionsDownload as PowerPoint slide