Method of operating a long direct-fired inclined counterflow rotary kiln for the thermal treatment of material and counterflow rotary kiln adapted for same, whereby material to be treated is introduced into the kiln at the inlet end and treated material is evacuated from the kiln at the outlet end, whereby a main combustion zone extends inside the kiln over a distance of to of the internal length L.sub.int of the kiln, whereby a supplementary combustion zone in which supplementary combustion takes place with an oxygen-rich oxidant extends inside the kiln over a distance from the inlet end of at most of the internal length L.sub.int, and whereby no combustion takes place in a heat exchange zone located between the main combustion zone and the supplementary combustion zone.

A method for manufacturing a positive electrode active material for a lithium ion secondary battery involves reacting at least 95 mass % of a lithium compound through a heat treatment step using a rotary firing furnace and having a batch firing process for heating a precursor while rolling the same in a heating region in a furnace tube, wherein the batch firing process has: a tilted input stage for tilting the furnace tube and inputting the precursor from an inlet of the firing furnace; a horizontal firing stage for performing firing while making the furnace tube horizontal; and a tilted discharge stage for tilting the furnace tube and discharging a fired powder from an outlet of the firing furnace.

A process for obtaining metal powders, preferentially iron powder, for burners to produce energy is described. The metal powders are obtained from metal oxide powders, preferentially iron oxide powders. The method comprises a step of preparing, during which the metal oxide powders, obtained during the combustion of the metal powders in burners, are prepared, a step of reduction, during which the metal oxide powders are reduced in a treatment chamber having an atmosphere comprising hydrogen and at a temperature of at least 900 C., preferentially at least 1000 C., obtaining reduced metal oxides, preferentially reduced iron oxides; and a step of pulverization, during which the reduced metal oxides are pulverized to obtain the metal powders.

In a reaction apparatus, a kiln part includes a supply port configured to receive a raw material supplied to one end side thereof, a discharge port configured to discharge a reaction product to another end side thereof, a cylindrical par extending along and rotatable around a central axis thereof, and a baffle plate provided so as to extend from an inner wall of the cylindrical part and pass through a central area of the cylindrical part including the central axis thereof. A driving part rotates the kiln part around the central axis. A heating part heats an outer peripheral part of the kiln part. The kiln part is configured so that a received predetermined raw material is conveyed to the discharge port along the central axis while being in contact with the baffle plate.

In a reaction apparatus, a kiln part includes a supply port configured to receive a raw material supplied to one end side thereof, a discharge port configured to discharge a reaction product to another end side thereof, a cylindrical par extending along and rotatable around a central axis thereof, and a baffle plate provided so as to extend from an inner wall of the cylindrical part and pass through a central area of the cylindrical part including the central axis thereof. A driving part rotates the kiln part around the central axis. A heating part heats an outer peripheral part of the kiln part. The kiln part is configured so that a received predetermined raw material is conveyed to the discharge port along the central axis while being in contact with the baffle plate.

An active material recovery apparatus capable of easily recovering an electrode active material from an electrode scrap in its intrinsic shape and a positive electrode active material reuse method using the active material recovery apparatus are provided. The active material recovery apparatus which is a rotary firing apparatus comprising a rod in a screw type therein includes a heat treatment bath and a screening wall arranged in a line along an axis of the rod, wherein the heat treatment bath constitutes a heating zone, and the screening wall constitutes a cooling zone; and an exhaust injection and degassing system, wherein the heat treatment bath removes a binder and a conductive material in an active material layer by performing heat treatment on an electrode scrap comprising the active material layer on a current collector in an air while rotating the electrode scrap around the axis of the rod and separates the current collector from the active material layer, and an active material in the active material layer passes through the screening wall and is recovered as an active material in powder form, and the current collector that does not pass through the screening wall is recovered separately.