An apparatus for thermally treating mineral solids includes a preheater, a separating apparatus arranged at an outlet of an entrained flow reactor, and a thermal treatment zone at an outlet of a gas stream of the separating apparatus, with an outlet of the treatment zone being connected to an inlet of the preheater for the gas stream. A process may involve preheating a mineral material, thermally treating the mineral material in an entrained flow reactor in a reducing atmosphere for reducing coloring metal compounds, separating a solid/gas mixture from the entrained flow reactor in a separating apparatus, oxidizing reducing constituents of a gas from the separating apparatus in a thermal treatment zone between the separating apparatus and the preheater via supplied oxygen, and supplying gas emerging from the thermal treatment zone to the preheater and thereby utilizing thermal energy recovered in the thermal treatment zone by transfer to mineral material

The invention provides a powder-gas heat exchanger for exchanging heat between a powder stream and a gas stream in counter-current flow comprising a powder stream mass flow rate substantially equal to a gas stream mass flow rate in a vertical shaft heat exchanger. A hot gas stream may be adapted for use in heating a cool solids stream, or a cool gas stream may be adapted for use in cooling a hot solids stream.

A molten metal scrap submergence system comprising a furnace and a vortexing scrap submergence well. The vortexing scrap submergence well includes a diverter suspended above the well and oriented for immersion in a bath of molten metal circulating within the well. The system, or an alternative scrap submergence system, can include a hood element disposed in an overlapping position with regard to a top opening of the scrap submergence well. The hood at least substantially seals the top opening. The hood element includes a scrap piece feed chute and a burner allowing carbon containing vapor evaporated from the surface of the molten scrap pieces to combust and form predominantly water. The system, or an alternative scrap submergence system can include internal side walls of the well with a first diameter portion adjacent and above said ramp and a second, larger diameter portion above said first portion.

In the disclosed solution sand to be cleaned is thermally cleaned by rotating the sand being cleaned in a large oven (1) by rotating the oven (1). Before cleaning, the sand may be pre-processed by crushing any lumps and cleaning the sand fraction by magnetic separation. Preprocessed sand to be cleaned and heat energy are fed (5) into the rotating oven. The oven (1) is set slightly inclined so that a second end of the oven (1) is lower than a first end. The inclination and rotating speed of the oven (1) as well as the feed amount of sand are adjusted, whereby the advancing speed of the sand may be adjusted, as well as the ratio of the sand being cleaned to the volume of the oven (1) kept as desired. The temperature of the oven (1) is monitored at the coldest area of the oven, which is substantially at the second end of the oven. The temperature of the oven (1) is adjusted by adjusting the amount of heat energy fed in. By means of temperature monitoring and knowing the advancing speed of the sand, it is also possible to determine the average temperature of the sand and adjust it as desired by adjusting the supplied heat energy. Finally, the cleaned sand is let run (12) from the second end of the oven (1).

In the disclosed solution sand to be cleaned is thermally cleaned by rotating the sand being cleaned in a large oven (1) by rotating the oven (1). Before cleaning, the sand may be pre-processed by crushing any lumps and cleaning the sand fraction by magnetic separation. Preprocessed sand to be cleaned and heat energy are fed (5) into the rotating oven. The oven (1) is set slightly inclined so that a second end of the oven (1) is lower than a first end. The inclination and rotating speed of the oven (1) as well as the feed amount of sand are adjusted, whereby the advancing speed of the sand may be adjusted, as well as the ratio of the sand being cleaned to the volume of the oven (1) kept as desired. The temperature of the oven (1) is monitored at the coldest area of the oven, which is substantially at the second end of the oven. The temperature of the oven (1) is adjusted by adjusting the amount of heat energy fed in. By means of temperature monitoring and knowing the advancing speed of the sand, it is also possible to determine the average temperature of the sand and adjust it as desired by adjusting the supplied heat energy. Finally, the cleaned sand is let run (12) from the second end of the oven (1).

A rotary kiln includes: a heating tube; a material feeding unit disposed on a first end of the heating tube; a material collection unit disposed on a second end of the heating tube; an inner cylinder supported at the second end of the heating tube with the inner cylinder being inserted in a central portion of the heating tube; a plurality of branch tubes disposed circumferentially on an outer circumferential surface of the inner cylinder, each of the branch tubes branching from the inner cylinder and extending in an axial direction along an inner circumferential surface of the heating tube; a hot air supply tube supported to be relatively rotatable with respect to the inner cylinder with the hot air supply tube being inserted in one end of the inner cylinder that extends outside the heating tube; and a drive mechanism that rotates the heating tube.

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.

Disclosed is a method for producing sintered material from organic raw materials, implemented in an apparatus comprising, a cyclone preheater, a rotary furnace and a grate cooler, and in which the raw materials are preheated in the cyclone preheater, the preheated material is calcined and sintered in the rotary furnace, and the calcined materials are cooled by blowing cooling air in the grate cooler, producing hot air. The hot air is separated into three upstream-to-downstream fractions, the three hot air fractions being at decreasing temperatures. The first air fraction acts as combustion air in at least the combustion zone of the rotary furnace and/or of the potential precalciner of the apparatus. The second air fraction is greater than the combustion air needs to produce energy. The third air fraction is directed at least in part to the combustion zone of the apparatus, providing combustion air with the first air fraction.

A chlorine bypass device which can cool exhaust gas quickly by mixing extracted exhaust gas with cooling air at high efficiency, to thereby produce fine chloride dust, and increase dust recovery efficiency.

A chlorine bypass device which can cool exhaust gas quickly by mixing extracted exhaust gas with cooling air at high efficiency, to thereby produce fine chloride dust, and increase dust recovery efficiency.