A kiln for firing ceramic slabs comprising: a heating module, a firing module, a cooling module, consecutively connected to each other along an advancement direction of the slabs, which define a process chamber provided with an inlet opening and an outlet opening; a transport system (T1,T2) arranged along the process chamber from the inlet opening to the outlet opening, structured to transport the slabs along the advancement direction; wherein the process chamber comprises at least a first channel and at least a second channel, thermally isolated from one another, each of which extends along the advancement direction from the inlet opening to the outlet opening; wherein the transport system (T1,T2) comprises at least a first transport line and at least a second transport line, respectively arranged along the first channel and along the second channel from the inlet opening to the outlet opening; characterised in that: the heating module and/or the cooling module comprise a plurality of sub-modules (22,42), flanked to one another along the slab advancement direction; each sub-module (22,42) is separated from the adjacent sub-modules by means of insulating partitions, provided with openings, aligned with each other along the advancement direction, to allow the transit of the slabs, and wherein each sub-module (22,42) is provided with temperature adjusting means independent of the other sub-modules (22,42). a heating module, a firing module, a cooling module, consecutively connected to each other along an advancement direction of the slabs, which define a process chamber provided with an inlet opening and an outlet opening; a transport system (T1,T2) arranged along the process chamber from the inlet opening to the outlet opening, structured to transport the slabs along the advancement direction; wherein the process chamber comprises at least a first channel and at least a second channel, thermally isolated from one another, each of which extends along the advancement direction from the inlet opening to the outlet opening; wherein the transport system (T1,T2) comprises at least a first transport line and at least a second transport line, respectively arranged along the first channel and along the second channel from the inlet opening to the outlet opening; characterised in that: the heating module and/or the cooling module comprise a plurality of sub-modules (22,42), flanked to one another along the slab advancement direction; each sub-module (22,42) is separated from the adjacent sub-modules by means of insulating partitions, provided with openings, aligned with each other along the advancement direction, to allow the transit of the slabs, and wherein each sub-module (22,42) is provided with temperature adjusting means independent of the other sub-modules (22,42). the heating module and/or the cooling module comprise a plurality of sub-modules (22,42), flanked to one another along the slab advancement direction; each sub-module (22,42) is separated from the adjacent sub-modules by means of insulating partitions, provided with openings, aligned with each other along the advancement direction, to allow the transit of the slabs, and wherein each sub-module (22,42) is provided with temperature adjusting means independent of the other sub-modules (22,42).