A shaft furnace for firing carbonate-containing material may include, in a flow direction of the material, a preheating zone, a firing zone, a cooling zone, and a material outlet for discharging the material from the shaft furnace. Burner lances project into the firing zone. At least one burner lance has a first penetration depth into the firing zone and at least one further burner lance has a second penetration depth into the firing zone that is greater than the first penetration depth. A primary air conduit may be configured to convey combustion air and may be connected to at least one burner lance. An oxygen conduit for conveying oxygen into the firing zone may be arranged such that oxygen flows from the oxygen conduit at least one burner lance having the second penetration depth.

A shaft furnace for firing carbonate-containing material may include, in a flow direction of the material, a preheating zone, a firing zone, a cooling zone, and a material outlet for discharging the material from the shaft furnace. Burner lances project into the firing zone. At least one burner lance has a first penetration depth into the firing zone and at least one further burner lance has a second penetration depth into the firing zone that is greater than the first penetration depth. A primary air conduit may be configured to convey combustion air and may be connected to at least one burner lance. An oxygen conduit for conveying oxygen into the firing zone may be arranged such that oxygen flows from the oxygen conduit at least one burner lance having the second penetration depth.

A method for the thermal treatment of mineral raw materials such as limestone or dolomite is shown and described, which includes at least the following steps of a. providing a mineral bulk material and a conductive material and b. placing the mineral bulk material and the conductive material into a kiln, generating an electromagnetic field inside the kiln, thermally treating the mineral bulk material in the kiln by means of electromagnetic excitation of the conductive material in the electromagnetic field, and removing the thermally treated mineral bulk material and the conductive material from the kiln. Using the method described, even large quantities of mineral bulk material can be efficiently converted.

A method for the thermal treatment of mineral raw materials such as limestone or dolomite is shown and described, which includes at least the following steps of a. providing a mineral bulk material and a conductive material and b. placing the mineral bulk material and the conductive material into a kiln, generating an electromagnetic field inside the kiln, thermally treating the mineral bulk material in the kiln by means of electromagnetic excitation of the conductive material in the electromagnetic field, and removing the thermally treated mineral bulk material and the conductive material from the kiln. Using the method described, even large quantities of mineral bulk material can be efficiently converted.

A method for calcining and cooling material such as carbonate rocks may be employed in a parallel-flow regenerative shaft kiln that has two shafts, which are operated alternately as a calcining shaft and as a regenerative shaft. Material flows through a preheating zone, a calcining zone, and a cooling zone to a product outlet. At least one gas flow is compressed by a high-pressure fan and introduced into the parallel-flow regenerative shaft kiln. The high-pressure fan is configured as an axial fan or as a radial fan, having an impeller through which flow takes place axially or radially. A parallel-flow regenerative shaft kiln may also be utilized to perform such methods.

A method for calcining and cooling material such as carbonate rocks may be employed in a parallel-flow regenerative shaft kiln that has two shafts, which are operated alternately as a calcining shaft and as a regenerative shaft. Material flows through a preheating zone, a calcining zone, and a cooling zone to a product outlet. At least one gas flow is compressed by a high-pressure fan and introduced into the parallel-flow regenerative shaft kiln. The high-pressure fan is configured as an axial fan or as a radial fan, having an impeller through which flow takes place axially or radially. A parallel-flow regenerative shaft kiln may also be utilized to perform such methods.

A system for making oxide material may comprise a preheating cyclone stage for receiving a solid carbonate material and operating at a temperature less than a calcination temperature of the solid carbonate material, a calcination cyclone stage for heating the preheated solid carbonate material and operating at a temperature of at least the calcination temperature to convert the preheated solid carbonate material to a solid oxide material and carbon dioxide gas, a cooling cyclone stage for cooling the solid oxide material and operating at a temperature less than the calcination temperature to cool the solid oxide material to ambient temperature, a first recirculating system to extract and recirculate a first gas from an outlet of the calcination cyclone stage to an inlet of the calcination cyclone stage zone, and a second recirculating system to extract and recirculate a second gas from the cooling cyclone stage to the preheating cyclone stage.

A system for making oxide material may comprise a preheating cyclone stage for receiving a solid carbonate material and operating at a temperature less than a calcination temperature of the solid carbonate material, a calcination cyclone stage for heating the preheated solid carbonate material and operating at a temperature of at least the calcination temperature to convert the preheated solid carbonate material to a solid oxide material and carbon dioxide gas, a cooling cyclone stage for cooling the solid oxide material and operating at a temperature less than the calcination temperature to cool the solid oxide material to ambient temperature, a first recirculating system to extract and recirculate a first gas from an outlet of the calcination cyclone stage to an inlet of the calcination cyclone stage zone, and a second recirculating system to extract and recirculate a second gas from the cooling cyclone stage to the preheating cyclone stage.

A system for making oxide material may comprise a preheating cyclone stage for receiving a solid carbonate material and operating at a temperature less than a calcination temperature of the solid carbonate material, a calcination cyclone stage for heating the preheated solid carbonate material and operating at a temperature of at least the calcination temperature to convert the preheated solid carbonate material to a solid oxide material and carbon dioxide gas, a cooling cyclone stage for cooling the solid oxide material and operating at a temperature less than the calcination temperature to cool the solid oxide material to ambient temperature, a first recirculating system to extract and recirculate a first gas from an outlet of the calcination cyclone stage to an inlet of the calcination cyclone stage zone, and a second recirculating system to extract and recirculate a second gas from the cooling cyclone stage to the preheating cyclone stage.

Process for calcining mineral rock in a regenerative parallel-flow vertical shaft furnace, containing at least two shafts (1, 2) interconnected by a gas transfer channel (3), each shaft operating alternately in firing mode and in preheating mode, the firing mode comprising a combustion of fuel in the presence of air so as to obtain a firing of the rock to give calcined rock, an emission of combustion gases, and a passage of these gases from one shaft to the other by means of said channel (3), the preheating mode comprising a heat exchange between said rock and said combustion gases from said channel (3), this process additionally comprising an injection of supplementary air into said channel (3) with oxidation of unburnt products contained in the combustion gases passing through this channel.