A method for calcining mineral rock in a regenerative parallel-flow vertical shaft furnace including the steps of collecting a portion of the gaseous effluent discharged, in preheating mode, from the furnace shaft in a recirculating circuit, forming an oxidizing mixture by mixing the portion collected from the gaseous effluent with concentrated dioxygen from a dioxygen source, and inserting the oxidizing mixture into the top of the shaft in firing mode so as to ensure the combustion of fuel in the presence of oxygen. The gaseous effluent discharged from the furnace having a high concentration of CO.sub.2.

A method for calcining mineral rock in a regenerative parallel-flow vertical shaft furnace including the steps of collecting a portion of the gaseous effluent discharged, in preheating mode, from the furnace shaft in a recirculating circuit, forming an oxidizing mixture by mixing the portion collected from the gaseous effluent with concentrated dioxygen from a dioxygen source, and inserting the oxidizing mixture into the top of the shaft in firing mode so as to ensure the combustion of fuel in the presence of oxygen. The gaseous effluent discharged from the furnace having a high concentration of CO.sub.2.

A method for calcining mineral rock in a regenerative parallel-flow vertical shaft furnace including the steps of collecting a portion of the gaseous effluent discharged, in preheating mode, from the furnace shaft in a recirculating circuit, forming an oxidizing mixture by mixing the portion collected from the gaseous effluent with concentrated dioxygen from a dioxygen source, and inserting the oxidizing mixture into the top of the shaft in firing mode so as to ensure the combustion of fuel in the presence of oxygen. The gaseous effluent discharged from the furnace having a high concentration of CO.sub.2.

A method for calcining mineral rock in a regenerative parallel-flow vertical shaft furnace including the steps of collecting a portion of the gaseous effluent discharged, in preheating mode, from the furnace shaft in a recirculating circuit, forming an oxidizing mixture by mixing the portion collected from the gaseous effluent with concentrated dioxygen from a dioxygen source, and inserting the oxidizing mixture into the top of the shaft in firing mode so as to ensure the combustion of fuel in the presence of oxygen. The gaseous effluent discharged from the furnace having a high concentration of CO.sub.2.

A method for calcining mineral rock in a regenerative parallel-flow vertical shaft furnace including the steps of collecting a portion of the gaseous effluent discharged, in preheating mode, from the furnace shaft in a recirculating circuit, forming an oxidizing mixture by mixing the portion collected from the gaseous effluent with concentrated dioxygen from a dioxygen source, and inserting the oxidizing mixture into the top of the shaft in firing mode so as to ensure the combustion of fuel in the presence of oxygen. The gaseous effluent discharged from the furnace having a high concentration of CO.sub.2.

A method for calcining mineral rock in a regenerative parallel-flow vertical shaft furnace including the steps of collecting a portion of the gaseous effluent discharged, in preheating mode, from the furnace shaft in a recirculating circuit, forming an oxidizing mixture by mixing the portion collected from the gaseous effluent with concentrated dioxygen from a dioxygen source, and inserting the oxidizing mixture into the top of the shaft in firing mode so as to ensure the combustion of fuel in the presence of oxygen. The gaseous effluent discharged from the furnace having a high concentration of CO.sub.2.

The present invention relates to a device for heat-treating solid material, in particular in granular form, wherein the device comprises a kiln and an external heat generator, wherein said kiln comprises at least one sloped sliding surface on which a bed of said solid material slides down within said kiln due to gravity while a hot gas generated by the external heat generator is led through said solid material to heat said solid material to a desired temperature in order to change the substance properties of said solid material. According to the invention, said external heat generator for generating said hot gas is external to said kiln, wherein said kiln further comprises at least one kiln gas inlet through which said hot gas enters said kiln, such that the necessary temperature of said hot gas can be controlled precisely in that said hot gas is generated in said external heat generator, ensuring that the solid material does not experience temperatures above an allowed maximum temperature, and further such that the solid material is not exposed to radiation from a burner.

A melting furnace for melting a metallic material includes a receiving region for receiving the metallic material, a gas-burning device where the gas-burning device is disposed in the receiving region and where metallic material disposed in the receiving region is heatable and meltable by burning a gas by the gas-burning device, a heat-retention region, and an electrically operable heating device where a melt in the heat-retention region is able to be kept warm by the electrically operable heating device.

A melting furnace for melting a metallic material includes a receiving region for receiving the metallic material, a gas-burning device where the gas-burning device is disposed in the receiving region and where metallic material disposed in the receiving region is heatable and meltable by burning a gas by the gas-burning device, a heat-retention region, and an electrically operable heating device where a melt in the heat-retention region is able to be kept warm by the electrically operable heating device.