干燥过程纯系物理变化过程，而焙烧过程是改变了原材料中矿物组成的物理——化学反应的综合过程，因此也是非常复杂的过程。焙烧中形成了新的矿物相，一般也会有液相的产生，液相在冷却时凝固成为玻璃相。这些转化的形式和范围取决于原材料的矿物成分、颗粒组成、化学成分；焙烧时的升温速度、焙烧温度、高温范围内的保温时间；以及制品的形状、窑内气氛等。
The drying process is purely a physical change process, and the roasting process is a comprehensive process of physical and chemical reactions that change the mineral composition of raw materials, so it is also a very complex process. New mineral phase is formed during calcination, and liquid phase usually occurs. Liquid phase solidifies into glass phase when cooled. The form and range of these transformations depend on the mineral composition, particle composition and chemical composition of raw materials; the heating rate, roasting temperature, holding time in the high temperature range; the shape of products and the atmosphere in the kiln.
在砖的生产中，焙烧是关键的环节。产品质量的好坏，最后决定于焙烧工序。为了保证产品的产量、质量和隧道窑的稳定操作，在烧成过程中必须有合理的烧成热工制度，即适合于制品矿物组成特点的温度制度，适合于制品烧成要求的气氛以及压力制度。
In the production of brick, roasting is the key link. The quality of the product depends on the roasting process. In order to ensure the output and quality of products and the stable operation of tunnel kiln, there must be a reasonable firing thermal system during the firing process, that is, the temperature system suitable for the mineral composition characteristics of products, the atmosphere and pressure system suitable for the firing requirements of products.