Preparation of Lead-free Base Glaze Suitable for Pearlescent Pigments by Low-temperature Solid-phase Reaction with Alkali Waste

A lead-free base glaze suitable for pearlescent pigments was prepared by a low-temperature solid-phase reaction with alkali waste. Tests were performed to evaluate the effects of the sintering conditions and alkali waste composition on the prepared base glaze and pearlescent glaze. The experimental results show that partially replacing SiO 2 with B 2 O 3 effectively reduced the sintering temperature and time to form a glass network, but the network structure becomes disconnected as the B 2 O 3 content increases. An amorphous base glaze was obtained when soda ash was replaced with a small amount of alkali waste, but increasing the addition of NaCl further was adverse to base glaze formation by resulting in crystallization of the base glaze and a decrease in the bridging oxygen content. The pearlescent pigment was thermally stable in the glaze at 750 °C, while higher temperatures caused the crystalline phase of NaAlSiO 4 to appear and adhere to the surface of pigment granules, which degraded the pearlescent effect of the glaze.