LICA

Lithium carbonate is a powerful flux — about two-fifths of its weight is lithium oxide, and a small addition does visible work in a glaze. The remainder leaves as carbon dioxide during the firing.

Lithium carbonate begins fluxing around 800°C and goes on working above that. It is strong enough that a glaze usually carries only a few parts in a hundred, with reactive glazes running higher, and it brightens colour the way the alkalis do — of the alkalis it is also the one that adds least to a glaze's thermal expansion. About three-fifths of its weight leaves as carbon dioxide during the firing, which is a good deal of gas to come off through a melt. It also dissolves in water a little, unusually for a raw glaze material, so some of it travels with the water as a glaze dries and can concentrate at the surface.