A thermal treatment method of used tyres based on the pre-heating of the previously crushed raw material within a feeding mechanism of the reactor which allows to increase the efficiency of the thermal treatment through the reduction of energy consumption by means of the use of residual energy being said method CHARACTERIZED in that it comprises the following stages: a) supplying said previously crushed used tyres to a conveyor, (b) feeding said previously crushed used tyres from said conveyor to a feeding mechanism located on a reactor; (c) pre-heating previously crushed used tyres located in the inside of said feeding mechanism having a first flow of first exhaust fumes coming from an Internal Combustion Engine (hereinafter ICE); (d) feeding said previously crushed and heated used tyres from the inside of said feeding mechanism to said reactor, (e) supplying a second flow of exhaust fumes coming from said ICE through a first gas connecting tube located in the intermediate zone of said reactor or reaction thermolysis zone, creating in said reactor an oxygen-free environment, thus generating with said thermolysis reaction a gas thermolysis flow exiting the reactor through an outlet and a volume of solid thermolysis products which fall towards the lower portion of said reactor; (f) recirculating gases used in stage (c) where the previously pre-heated crushed used tyres are preheated from the inside of said feeding mechanism towards an inlet tube located in a lower cooling zone of reactor to cool the solid thermolysis products obtained in stage (e); (g) discharging the solid thermolysis products cooled in the stage (f) as carbon black, mineral aggregates of tyres; metallic reinforcement and others exiting by the lower part of the reactor through a feeder airlock towards a means for receiving the solid thermolysis products; (h) delivering the solid thermolysis products cooled through an airlock feeder towards a magnetic separator to separate the solid thermolysis products, carbon black and others from the metallic reinforcement; and (i) recirculating said thermolysis gas flow exiting the reactor through an outlet obtained in stage (e) towards said first gas connecting tube located in the intermediate zone of said reactor or thermolysis reaction zone, performing a mixture of said gas and the exhaust fumes from the ICE by means of an ejector mechanism. a) supplying said previously crushed used tyres to a conveyor, (b) feeding said previously crushed used tyres from said conveyor to a feeding mechanism located on a reactor; (c) pre-heating previously crushed used tyres located in the inside of said feeding mechanism having a first flow of first exhaust fumes coming from an Internal Combustion Engine (hereinafter ICE); (d) feeding said previously crushed and heated used tyres from the inside of said feeding mechanism to said reactor, (e) supplying a second flow of exhaust fumes coming from said ICE through a first gas connecting tube located in the intermediate zone of said reactor or reaction thermolysis zone, creating in said reactor an oxygen-free environment, thus generating with said thermolysis reaction a gas thermolysis flow exiting the reactor through an outlet and a volume of solid thermolysis products which fall towards the lower portion of said reactor; (f) recirculating gases used in stage (c) where the previously pre-heated crushed used tyres are preheated from the inside of said feeding mechanism towards an inlet tube located in a lower cooling zone of reactor to cool the solid thermolysis products obtained in stage (e); (g) discharging the solid thermolysis products cooled in the stage (f) as carbon black, mineral aggregates of tyres; metallic reinforcement and others exiting by the lower part of the reactor through a feeder airlock towards a means for receiving the solid thermolysis products; (h) delivering the solid thermolysis products cooled through an airlock feeder towards a magnetic separator to separate the solid thermolysis products, carbon black and others from the metallic reinforcement; and (i) recirculating said thermolysis gas flow exiting the reactor through an outlet obtained in stage (e) towards said first gas connecting tube located in the intermediate zone of said reactor or thermolysis reaction zone, performing a mixture of said gas and the exhaust fumes from the ICE by means of an ejector mechanism.