Abstract: The firing tests with clay blocks were undertaken to study the fluorine expulsion and
retention characteristics of calcium-based materials during the firing of brick clays. The
results indicate that fluorine expulsion begins at approx. 600-700℃, and the main portion
occurs in 800-1000℃. The mode of firing has some effects on fluorine expulsion. Additives
of calcium-based material can reduce fluorine expulsion, which is mainly attributed to the
increased formation of CaF2 during clay firing. In addition, the optimum addition tests of
6 calcium-based materials with higher efficiency were carried out in a brick kiln. More
than 75% fluorine is retained in the brick body and there is no adverse effect on brick
product. This makes it possible for brickyard to achieve non-polluting production.

Key words: fluorine expulsion, fluorine retention, calcium-based materials, brick making

摘要： The firing tests with clay blocks were undertaken to study the fluorine expulsion and
retention characteristics of calcium-based materials during the firing of brick clays. The
results indicate that fluorine expulsion begins at approx. 600-700℃, and the main portion
occurs in 800-1000℃. The mode of firing has some effects on fluorine expulsion. Additives
of calcium-based material can reduce fluorine expulsion, which is mainly attributed to the
increased formation of CaF2 during clay firing. In addition, the optimum addition tests of
6 calcium-based materials with higher efficiency were carried out in a brick kiln. More
than 75% fluorine is retained in the brick body and there is no adverse effect on brick
product. This makes it possible for brickyard to achieve non-polluting production.

关键词: fluorine expulsion;fluorine retention;calcium-based materials;brick making