The calcination of limestone in normal shaft kilns is a complex process, since it is influenced by a variety of parameters. These influencing factors are:
the operating variables such as energy input, throughput, type of fuel, air flow,
the kiln parameters such as diameter, packed bed height, cooling zone length,
the limestone parameters such as mean particle size and material properties (thermal conductivity, coefficient of decomposition, decomposition pressure, calcite fraction, magnesite fraction, humidity, etc.)
ambient conditions (ambient temperature, air velocity, clouds).