A microwave heating apparatus is provided herein comprising a tubing conduit consisting of two or more removable bend portions connected to each other. The tubing conduit is supported by a support system. Each removable bend portion includes a microwave emitter to heat a fluid flowing through the conduit. The apparatus can replace or be integrated into existing heating equipment used in, for example, steam cracking of hydrocarbons. Also provided are pipe segments, such as spools, that are adapted for heating a fluid by applying microwave energy. The pipe segments can be lined with microwave absorbing materials and comprise an opening through which an insert comprising a microwave emitter can be removably inserted and retained.

A microwave heating device with reflection protection belongs to a technical field of microwave applications. A first port of a circulator is connected to a microwave generator, and a second port of the circulator is connected to a microwave transmission device. A water load comprises a waveguide section, a metamaterial structure layer and the absorption tube. One end of the waveguide section is connected to a third port of the circulator, and the other end is sealed by a metal plate. The metamaterial structure layer is arranged in the waveguide section, and a center of the metamaterial structure layer has an accommodation space. The absorption tube is arranged along an internal wall of the accommodation space with a spiral extending form. Both ends of the absorption tube penetrate the waveguide section, and coolant flows in the absorption tube. Relative dielectric constants of the metamaterial structure layer gradually increase.

A method and system for doping semiconductor materials using microwave exposure. In some embodiments, the surface of a semiconductor substrate coated with a layer of dopant material is exposed to a beam of microwave radiation, with the frequency of the microwave radiation chosen to coincide with a microwave absorption resonance of the dopant. A gyrotron is a preferred source of monochromatic microwaves capable of delivering the appropriate the power density. Under this microwave exposure, the dopant heats up and diffuses into the semiconductor. Since only the dopant is selectively excited, the atoms of the crystal lattice remain cooler. Additional cooling can be provided by a flow of cooling gas onto the surface. When the electric field of the microwave exposure is high enough to overcome the potential barrier of interstitial diffusion within the crystal, the dopants migrate to vacancies in the crystal lattice, and the semiconductor material becomes activated.

A method and system for doping semiconductor materials using microwave exposure. In some embodiments, the surface of a semiconductor substrate coated with a layer of dopant material is exposed to a beam of microwave radiation, with the frequency of the microwave radiation chosen to coincide with a microwave absorption resonance of the dopant. A gyrotron is a preferred source of monochromatic microwaves capable of delivering the appropriate the power density. Under this microwave exposure, the dopant heats up and diffuses into the semiconductor. Since only the dopant is selectively excited, the atoms of the crystal lattice remain cooler. Additional cooling can be provided by a flow of cooling gas onto the surface. When the electric field of the microwave exposure is high enough to overcome the potential barrier of interstitial diffusion within the crystal, the dopants migrate to vacancies in the crystal lattice, and the semiconductor material becomes activated.

A method and an apparatus method for producing direct reduced iron (DRI) from iron ore using biomass as a source of reductant and as a heating source of the iron ore and electromagnetic energy as a further heating source in a furnace having multiple zones. The zones include a preheat zone and a reduction zone between an inlet for briquettes of iron ore and biomass and an outlet for direct reduced iron. The method includes counter-current movement of (a) briquettes of iron ore and biomass in a direction from the inlet to the outlet and (b) combustible gases in an opposite direction in the furnace.

This invention refers to a technically and economically viable process for recovery of relevant metallic and non-metallic contents from mining residues, particularly the bauxite residue, using it in its integral form. Such a process route uses energy from microwaves, assisted leaching and logic sequencing of steps that allow a technically and economically viable removal of components from the bauxite residue, particularly the residue from the Bayer process. The invention also refers to a microwave reactor that is appropriate for performing the above-mentioned process, as well as to a method for heating a mining product.

This invention refers to a technically and economically viable process for recovery of relevant metallic and non-metallic contents from mining residues, particularly the bauxite residue, using it in its integral form. Such a process route uses energy from microwaves, assisted leaching and logic sequencing of steps that allow a technically and economically viable removal of components from the bauxite residue, particularly the residue from the Bayer process. The invention also refers to a microwave reactor that is appropriate for performing the above-mentioned process, as well as to a method for heating a mining product.

A process for direct reduction of iron ore in a solid state includes exposing briquettes of iron ore fragments and biomass to electromagnetic energy under anoxic conditions and generating heat within iron ore in the briquettes. The iron ore is reduced in a solid state within the briquettes, and the biomass provides a source of reductant.

A process for direct reduction of iron ore in a solid state includes exposing briquettes of iron ore fragments and biomass to electromagnetic energy under anoxic conditions and generating heat within iron ore in the briquettes. The iron ore is reduced in a solid state within the briquettes, and the biomass provides a source of reductant.

An apparatus includes a microwave source emitting energy in a frequency range of about 300 Mhz to about 300 Ghz. At microwave cavity includes a stationary input section, a stationary output section, and a rotating processing section between the input section and the sample output section. A waveguide introduces microwave energy into at least one of the sample input section and the sample output section.