- Soda ash is another name for sodium carbonate(Na2CO3). This fine granular material is an active flux and also serves an important function as a deflocculant in preparing liquid slip. It increases strength and workability and reduces shrinkage. Soda ash is often used as an important source of sodium (Na2O) in frits and glazes. It is also used in atmospheric soda firings, and as a key ingrediend in Egyptian paste.