The present invention relates to a rotary kiln for burning carbonate-containing material, in particular limestone or dolomite, including a rotary tube having an inlet end for feeding in the material to be burned and an outlet end for discharging the burned material; and a calciner unit which is arranged in the region of the outlet end, the rotary tube having an inlet zone at its inlet end and having an outlet zone at its outlet end, with a preheating zone and a burning zone being arranged between the inlet zone and the outlet zone in the transport direction of the material. The rotary kiln is characterized according to the invention in that a plurality of projections are arranged in the preheating zone of the rotary tube, the projections being arranged in groups one behind the other and substantially in parallel with the longitudinal axis of the rotary tube, with projections of adjacent groups of projections that are adjacent in the circumferential direction of the rotary tube being offset relative to one another in the longitudinal direction of the rotary tube such that spiral transport paths for the material to be burned are formed in the preheating zone. The present invention further relates to a method for burning carbonate-containing material, in particular limestone or dolomite.

The present invention relates to a rotary kiln for burning carbonate-containing material, in particular limestone or dolomite, including a rotary tube having an inlet end for feeding the material to be burned and an outlet end for discharging the burnt material, and a burner unit arranged in the region of the outlet end, the rotary tube having an inlet zone at its inlet end and an outlet zone at its outlet end, a preheating zone and a combustion zone being arranged between the inlet zone and outlet zone in the direction of transport of the material. The rotary kiln is characterized according to the invention in that at least one projection is arranged in the outlet zone of the rotary tube, the at least one projection having a contour tapering in the direction of rotation of the rotary tube. The present invention further relates to a method for burning carbonate-containing material, in particular limestone or dolomite.

Provided is a sintering furnace. The sintering furnace includes: a furnace body and a furnace head cover having a feed inlet, the furnace head cover covering a furnace head of the furnace body, the furnace head cover being axially limited relative to the furnace head, the furnace body being rotatable around a central axis relative to the furnace head cover, and the feed inlet being in communication with an interior of the furnace body; a sliding support structure including a first sliding structure configured to support the furnace head cover, the furnace head cover being fixedly connected to the first sliding structure, and the first sliding structure being slidably arranged in a length direction of the furnace body; and a feeding device in communication with the feed inlet through a flexible connection pipe.

A tube module has a tube having a bore and made of a ceramic material; a heat insulator surrounding an outer circumferential surface of the tube and made of a ceramic material; and a flange provided along an edge of each of both surfaces of the heat insulator and formed in a band shape.

A tube module has a tube having a bore and made of a ceramic material; a heat insulator surrounding an outer circumferential surface of the tube and made of a ceramic material; and a flange provided along an edge of each of both surfaces of the heat insulator and formed in a band shape.

A process and an apparatus are disclosed for improved recovery of metal from hot and cold dross, wherein a dross-treating furnace is provided with a filling material with capacity to store heat. This filling material is preheated to a desired temperature by injection of an oxidizing gas to burn non-recoverable metal remaining in the filling material after tapping of the recoverable metal contained in the dross and discharging of the treatment residue. When dross is treated in such furnace, the heat emanating by conduction from the filling material is sufficient to melt and separate the recoverable metal contained in the dross, without addition of an external heat source, such as fuel or gas burners, plasma torches or electric arcs and without use of any salt fluxes. Furthermore, the recovered metal being in the molten state can be fed to the molten metal holding furnace without cooling the melt.

A process and an apparatus are disclosed for improved recovery of metal from hot and cold dross, wherein a dross-treating furnace is provided with a filling material with capacity to store heat. This filling material is preheated to a desired temperature by injection of an oxidizing gas to burn non-recoverable metal remaining in the filling material after tapping of the recoverable metal contained in the dross and discharging of the treatment residue. When dross is treated in such furnace, the heat emanating by conduction from the filling material is sufficient to melt and separate the recoverable metal contained in the dross, without addition of an external heat source, such as fuel or gas burners, plasma torches or electric arcs and without use of any salt fluxes. Furthermore, the recovered metal being in the molten state can be fed to the molten metal holding furnace without cooling the melt.

An apparatus for drying material for an asphalt mixing facility includes a rotary kiln rotatably drivable about an axis of rotation, in which the material is dried, wherein the rotary kiln has a material inlet and a material outlet, a heating unit coupled to the rotary kiln for feeding heat to the rotary kiln, wherein the heating unit is designed with a burner which has a burner housing having a longitudinal axis, an air duct arranged at the burner housing for feeding air, a swirling element for swirling the air in the burner housing relative to the longitudinal axis, a hydrogen gas line connected to the burner for feeding hydrogen gas into the burner, wherein a hydrogen gas nozzle is connected to the hydrogen gas line for discharging the hydrogen gas, a burner head arranged at the burner housing for generating a burner flame.

The present disclosure relates to the technical field of phosphogypsum dehydration treatment, and provides a device for harmless treatment of phosphogypsum by calcination using high-temperature ceramsite, including a rotary kiln, a first feeding unit, a second feeding unit and a sorting assembly, where the rotary kiln includes a first rotary kiln drum and a second rotary kiln drum; a first interlayer channel is formed between the first rotary kiln drum and the second rotary kiln drum, and a head end of the first interlayer channel is connected to a head end of the first rotary kiln drum; the first feeding unit is used to input high-temperature ceramsite into the first rotary kiln drum; the second feeding unit is used to input phosphogypsum into the first interlayer channel; the mixture in the first rotary kiln drum and the phosphogypsum in the first interlayer channel can exchange heat to dehydrate the phosphogypsum; the sorting assembly is used to sort the mixture output from the first rotary kiln drum to obtain calcined phosphogypsum. The present disclosure enables high calcination and dehydration efficiency of phosphogypsum, and can achieve low-carbon harmless treatment of phosphogypsum to obtain phosphorus building gypsum.