Klin firing with differential temperature gradients

A method for firing ware in a down-draft periodic kiln, the method comprising:

• positioning at least one stack of ware in a ware space of the down-draft periodic kiln, wherein the ware space is defined by:
• a crown;
• a hearth opposite the crown;
• a first sidewall spanning between the crown and the hearth;
• a second sidewall opposite the first sidewall and spanning between the crown and the hearth;
• a front wall bounded by the first sidewall, the second sidewall, the hearth, and the crown;
• a back wall opposite the front wall and bounded by the first sidewall, the second sidewall, the hearth, and the crown;
• a plurality of temperature control zones that are oriented in a vertical direction;
• and
• a plurality of temperature control zones that are oriented in a horizontal direction;
• heating the ware space in a first heating stage from an ambient temperature to a first temperature that is greater than the ambient temperature,
• heating the ware space in a second heating stage from the first temperature to a second temperature that is greater than the first temperature;
• or
• heating the ware space in a third heating stage from the second temperature to a top soak temperature that is greater than the second temperature, wherein at least one of the following conditions is satisfied:
• (i) during at least one of the first heating stage, the second heating stage, and the third heating stage, one temperature control zone of the plurality of temperature control zones that are oriented in the vertical direction has a setpoint temperature that is different from a setpoint temperature of at least one other temperature control zone of the plurality of temperature control zones that are oriented in the vertical direction;
• and
• (ii) during at least one of the first heating stage, the second heating stage, and the third heating stage, one temperature control zone of the plurality of temperature control zones that are oriented in the horizontal direction has a setpoint temperature that is different from a setpoint temperature of at least one other temperature control zone of the plurality of temperature control zones that are oriented in the horizontal direction.