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 direct reduction of metal oxide-containing starting materials to produce metallized material by contact with hot reduction gas in a reduction unit (1), wherein the product of the direct reduction is discharged from the reduction unit (1) by means of a product discharge device (3) which is flushed with seal gas and from which vent gas is drawn and subsequently de-dusted. The vent gas is de-dusted dry and the content of at least one gaseous constituent is reduced by catalytic conversion or combustion. Also, a device for carrying out the method is disclosed.

A method for direct reduction of metal oxide-containing starting materials to produce metallized material by contact with hot reduction gas in a reduction unit (1), wherein the product of the direct reduction is discharged from the reduction unit (1) by means of a product discharge device (3) which is flushed with seal gas and from which vent gas is drawn and subsequently de-dusted. The vent gas is de-dusted dry and the content of at least one gaseous constituent is reduced by catalytic conversion or combustion. Also, a device for carrying out the method is disclosed.

The invention is concerned with a method for producing a cement comprising milled cement clinker and a supplementary cementitious material, wherein the method comprises the steps of: producing the milled cement clinker by a clinkerization process, comprising the steps of calcining and subsequently milling a limestone-based raw material; producing the supplementary cementitious material by calcining a raw material of the supplementary cementitious material at a temperature of less than 980° C. and subsequently milling the calcined raw material of the supplementary cementitious material, wherein the raw material of the supplementary cementitious material has an average particle size of 1 to 300 mm; and blending the milled cement clinker and the supplementary cementitious material; wherein the method is a continuous process comprising the step of calcining the raw material of the supplementary cementitious material in a kiln with a separate heating unit and/or combustion unit. Further, the invention is concerned with a method for producing a cement comprising milled cement clinker and a supplementary cementitious material, wherein the method comprises the steps of: producing the milled cement clinker by a clinkerization process, comprising the steps of calcining and subsequently milling a limestone-based raw material; producing the supplementary cementitious material by calcining a raw material of the supplementary cementitious material at a temperature of less than 980° C. and subsequently milling the calcined raw material of the supplementary cementitious material, wherein the raw material of the supplementary cementitious material has an average particle size of 1 to 300 mm, wherein at least 5 wt % of the particles have a particle size of above 4.75 mm; and blending the milled cement clinker and the supplementary cementitious material. The invention is also concerns a cement comprising milled cement clinker and a supplementary cementitious material, wherein the supplementary cementitious material comprises an amorphous constituent of more than 30 wt % as measured by XRD, wherein the supplementary cementitious material comprises less than 70 wt % of inert components selected from the group comprising mullite, spinel, feldspar, diopside, mica, or combinations thereof, and wherein the color of the cement in the range of 130-160, 130-160, 120-160, wherein the measurement of the cement color is conducted by a RGB2 colorimeter, wherein the colors are referenced to a RGB scale of 0 to 255.

A process for producing graphite in a vertical graphitization furnace having at least one process chamber that bounds a heating zone, a temperature of 2200° C. to 3200° C. is generated in the heating zone, particulate graphitizable material is supplied to the process chamber through an inlet, graphitizable material is conveyed through the heating zone of the process chamber, in which it is graphitized to graphite, and graphite obtained is removed from the process chamber through an outlet. In some variants, graphitizable material wherein the particles have a particle size of less than 3 mm is used, and/or, a material column is formed throughout the heating zone of a particular process chamber, wherein graphitizable material, after being supplied through the inlet from the top, trickles through an intake zone of the process chamber onto the material column, and/or, a material column is formed in a stationary heating zone of a particular process chamber encompassed by the heating zone, wherein graphitizable material, after being supplied through the intake from the top, trickles through a drop heating zone likewise encompassed by the heating zone onto the material column, and/or, graphitizable material in one or more material vessels is conveyed through a particular process chamber and through the heating zone thereof. Also specified is a vertical graphitization furnace optimized.

A process for producing graphite in a vertical graphitization furnace having at least one process chamber that bounds a heating zone, a temperature of 2200° C. to 3200° C. is generated in the heating zone, particulate graphitizable material is supplied to the process chamber through an inlet, graphitizable material is conveyed through the heating zone of the process chamber, in which it is graphitized to graphite, and graphite obtained is removed from the process chamber through an outlet. In some variants, graphitizable material wherein the particles have a particle size of less than 3 mm is used, and/or, a material column is formed throughout the heating zone of a particular process chamber, wherein graphitizable material, after being supplied through the inlet from the top, trickles through an intake zone of the process chamber onto the material column, and/or, a material column is formed in a stationary heating zone of a particular process chamber encompassed by the heating zone, wherein graphitizable material, after being supplied through the intake from the top, trickles through a drop heating zone likewise encompassed by the heating zone onto the material column, and/or, graphitizable material in one or more material vessels is conveyed through a particular process chamber and through the heating zone thereof. Also specified is a vertical graphitization furnace optimized.

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.

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 method for direct reduction of metal oxide-containing starting materials to produce metallized material by contact with hot reduction gas in a reduction unit (1), wherein the product of the direct reduction is discharged from the reduction unit (1) by means of a product discharge device (3) which is flushed with seal gas and from which vent gas is drawn and subsequently de-dusted. The vent gas is de-dusted dry and the content of at least one gaseous constituent is reduced by catalytic conversion or combustion. Also, a device for carrying out the method is disclosed.