Use of concentrated radiation for solar powered glass melting experiments

• Small scale demonstration of glass melting using concentrated simulated solar radiation.
• Complete conversion of raw materials to transparent glass with low gas content achieved.
• Semi-continuous flow of glass out of melting zone demonstrated.

To investigate the feasibility of using concentrated solar radiation to provide process heat for glass production, a high flux solar simulator was used to melt glass forming batches. Initial experiments involved melting various glass forming batches which demonstrated that rapid and full conversion of the crystalline raw materials into an X-ray amorphous vitreous state was possible. A pure silica batch produced an X-ray amorphous product but it was not possible to refine the melt in these exploratory tests. A powdered, ternary soda–lime–silica (SLS) glass forming batch melted vigorously, with rapid gas removal, resulting in a completely transparent glass. Industrial SLS pellets were subsequently used in semi-continuous melting experiments, whereby the batch was intermittently fed into the melting zone while the beam was kept on. Additional secondary heating and insulation around outlet of the melting zone was required to achieve a semi-continuous flow of molten glass to an output crucible.