A reactor comprises an outer sidewall and a bottom wall enclosing a hollow chamber comprising a lower fluidized bed zone and an upper freeboard zone. A plurality of inlets is provided for injecting at least one fluidizing medium into the fluidized bed zone and creating a swirling flow. At least one feed inlet communicates with the fluidized bed zone; and at least one product outlet is provided for removing a product from the chamber, the outlet(s) communicating with either the fluidized bed zone or the freeboard zone. The reactor has at least one internal barrier located inside the hollow chamber, and at least partly located in the fluidized bed zone. The internal barrier(s) have at least one opening within the fluidized bed zone, such as an underflow opening, to permit internal recirculation of material from the product zone to the feed zone, thereby simplifying reactor structure.

Oxygen is injected into the windbox of a fluidized bed ore roaster to form a fluidizing and oxidizing gas stream of elevated oxygen content which is fed into only the feed zone into which the ore to be fluidized is fed.

Oxygen is injected into the windbox of a fluidized bed ore roaster to form a fluidizing and oxidizing gas stream of elevated oxygen content which is fed into only the feed zone into which the ore to be fluidized is fed.

A process and its relating plant for recycling zinc oxide residues. Thereby, zinc oxide residues are granulated to particles with a size of d.sub.80 between 0.3 and 5 mm, preferably between 0.5 and 2 mm. These particles are fed into a roaster where they are thermally treated at a temperature in the range of 500 and 1.200? C., preferably 800 to 1.100? C. in a fluidized bed to form a calcine. The zinc oxide residues are zinc oxide dusts with a particle size below d.sub.80 100 ?m, preferably below d.sub.80 75 ?m coming from kiln, submerges lances furnaces, ferric reduction furnaces, galvanizing and/or recycling processes, particularly recycling of steel, copper, lead, nickel and/or electronic scrap, and/or that the zinc oxide residues comes from foundry for lead and zinc, ashes and/or dross from a Zamac process, oxide zinc ash, catalysts, melting and casting of Zn and/or zinc slag.

A process and its relating plant for recycling zinc oxide residues. Thereby, zinc oxide residues are granulated to particles with a size of d.sub.80 between 0.3 and 5 mm, preferably between 0.5 and 2 mm. These particles are fed into a roaster where they are thermally treated at a temperature in the range of 500 and 1.200? C., preferably 800 to 1.100? C. in a fluidized bed to form a calcine. The zinc oxide residues are zinc oxide dusts with a particle size below d.sub.80 100 ?m, preferably below d.sub.80 75 ?m coming from kiln, submerges lances furnaces, ferric reduction furnaces, galvanizing and/or recycling processes, particularly recycling of steel, copper, lead, nickel and/or electronic scrap, and/or that the zinc oxide residues comes from foundry for lead and zinc, ashes and/or dross from a Zamac process, oxide zinc ash, catalysts, melting and casting of Zn and/or zinc slag.

The invention relates to abed management cycle for a fluidized bed boiler, comprising the steps of: a) providing fresh ilmenite particles as bed material to the fluidized bed boiler; b) carrying out a fluidized bed combustion process; c) removing at least one ash stream comprising ilmenite particles from the fluidized bed boiler; d) separating ilmenite particles from the at least one ash stream; e) recirculating separated ilmenite particles into the bed of the fluidized bed boiler. The invention also relates to a corresponding arrangement for carrying out fluidized bed combustion, comprising a fluidized bed boiler comprising ilmenite particles as bed material; and a system for removing ash from the fluidized bed boiler; wherein the arrangement further comprises a separator for separating ilmenite particles from the re-moved ash; and means for recirculating separated ilmenite particles into the bed of the fluidized bed boiler.

A method for the heat treatment of granular solids includes initially introducing solids into a first reactor configured as a flash reactor or fluidized bed reactor where they are brought into contact with hot gases at temperatures in the range 500 C. to 1500 C. Next, the solids are passed through a residence time reactor in which they are fluidized. The residence time reactor is configured in a manner such that it has various regions which are separated from one another, from which the solid can be withdrawn in a manner such that it is provided with a variety of residence times in the residence time reactor.

A method for the heat treatment of granular solids includes initially introducing solids into a first reactor configured as a flash reactor or fluidized bed reactor where they are brought into contact with hot gases at temperatures in the range 500 C. to 1500 C. Next, the solids are passed through a residence time reactor in which they are fluidized. The residence time reactor is configured in a manner such that it has various regions which are separated from one another, from which the solid can be withdrawn in a manner such that it is provided with a variety of residence times in the residence time reactor.

There is provided a method for the removal of arsenic from an arsenical bearing sulfides ore, comprising a thermal treatment of arsenical sulfide in the presence of sulfur dioxide, yielding a calcine and a sublimate, the sublimate containing arsenious oxide. The method allows recovering metallic value from an arsenic-bearing metallic sulfides ore, by recovery of the calcine comprising the metallic value of the ore.

A suspension roasting system includes a feeding bin, a Venturi dryer, a first cyclone preheater, a second cyclone preheater, a pre-oxidation suspension roasting furnace, a thermal separation cyclone cylinder, a suspension and reduction roasting furnace, a collecting bin, a grinding machine, a magnetic ore separator and a draught fan. A suspension roasting method includes: crushing iron and manganese ores; conveying the ores to the Venturi dryer; starting the draught fan and enabling combustion gas in the Venturi dryer to be mixed with dust ores to remove water; enabling obtained solid materials to enter the pre-oxidation suspension roasting furnace after being preheated by the first and second cyclone preheaters; enabling obtained gas to enter the suspension and reduction roasting furnace through the thermal separation cyclone cylinder; performing suspension and reduction roasting; enabling obtained reducing slag powder to enter the collecting bin through cooling cyclone cylinders; and performing grinding and magnetic separation.