The invention discloses a multi-stage suspension magnetizing roasting-magnetic separation system and method for refractory iron ore, which belongs to the field of mineral processing technology. This system comprises multistage suspension preheater, multistage suspension oxidizer, multistage suspension redactor, on-line grade analyzer, ore-like splitter, magnetic separator, dust remover, roots blower and other components and connection modes. The refractory iron ore treated by the present method can be produced to homogeneous magnetite or maghemite accurately, and through magnetic separation, on-line grade analyzer detection and ore-like splitter, the concentrate powder which reach the set grade can be obtained, and the unqualified ore powder enters the next stage of oxidation-reduction-magnetic separation-split treatment. Through the present system and method, products with different roasting quality can be obtained, and can avoid the phenomenon of over burning or under burning occurring in the past process and equipment.

The invention makes public heating apparatus for vertically and helically conveying workpiece, including the main bracket, on which interconnected heating furnace and cooling furnace are arranged in parallel; The bracket is placed inside the heating furnace, the 1.sup.st spiral supporting plate is spiraling on the bracket, and conveyer belt is arranged on the 1.sup.st spiral supporting plate along spiral direction; one or multiple gas inlet/inlets are set on the heating furnace body to fill protective gas into furnace;

The 2.sup.nd spiral supporting plate is spiraling vertically inside the mentioned cooling furnace; the direction of the mentioned conveyer belt inside the cooling furnace is uniform to that of the 2.sup.nd spiral supporting plate; drive mechanism for conveyer belt is installed on the mentioned main bracket. One or multiple gas inlet/inlets are set on the cooling furnace body to fill protective gas into furnace; the conveyer belt runs through the mentioned heating furnace and cooling furnace and forms one loop via drive mechanism. The protective atmosphere spiral conveying heating furnace and spiral conveying cooling device is energy-saving and space saving with high efficiency.

A system and method for the fluidized direct reduction of iron ore concentrate powder. A two-phase fluidized bed is used for the direct reduction of iron ore concentrate powder. Each phase of the fluidized bed is formed by a bubbling bed and a circulating bed. Use of serial-connection processing involving gas and of high-gas-velocity processing of the circulating bed increase the gas utilization rate and the reduction efficiency of single-phase reduction. Once reduced gases are subjected to preheating, each gas is sent into an initial reduction phase and a final reduction phase so as to implement reduction of minerals. Use of mixed-connection processing involving gas appropriately reduces processing pressure. Hot flue gas produced by combustion in a gas heater is sent to a mineral pre-heating system that is used for pre-heating iron ore concentrate powder.

A system and method for the fluidized direct reduction of iron ore concentrate powder. A two-phase fluidized bed is used for the direct reduction of iron ore concentrate powder. Each phase of the fluidized bed is formed by a bubbling bed and a circulating bed. Use of serial-connection processing involving gas and of high-gas-velocity processing of the circulating bed increase the gas utilization rate and the reduction efficiency of single-phase reduction. Once reduced gases are subjected to preheating, each gas is sent into an initial reduction phase and a final reduction phase so as to implement reduction of minerals. Use of mixed-connection processing involving gas appropriately reduces processing pressure. Hot flue gas produced by combustion in a gas heater is sent to a mineral pre-heating system that is used for pre-heating iron ore concentrate powder.

A device for manufacturing molten iron is provided. The device for manufacturing the molten iron includes a multi-stage fluidized reduction furnace for reducing a powdered iron ore including hematite and limonite, a melting gas furnace connected to the fluidized reduction furnace through an ore conduit and a gas conduit, a fluidized bed oxidation furnace for oxidizing magnetite to be converted into hematite through steam provided from the fluidized reduction furnace, and a hydrogen processing unit for processing hydrogen generated by the oxidation reaction of magnetite in the fluidized bed oxidation furnace.

A device for manufacturing molten iron is provided. The device for manufacturing the molten iron includes a multi-stage fluidized reduction furnace for reducing a powdered iron ore including hematite and limonite, a melting gas furnace connected to the fluidized reduction furnace through an ore conduit and a gas conduit, a fluidized bed oxidation furnace for oxidizing magnetite to be converted into hematite through steam provided from the fluidized reduction furnace, and a hydrogen processing unit for processing hydrogen generated by the oxidation reaction of magnetite in the fluidized bed oxidation furnace.

An air distribution nozzle and fluidized bed including said nozzle, the nozzle including a gas inlet pipe and an air distribution cap defining a space inbetween them, first air outlet means allowing air to flow from the gas inlet pipe to the space and second outlet means allowing air to flow from said space to the ambient area, wherein said second outlet means has an outer cross section along the outer surface of the cap that varies in its vertical height along its horizontal extension.

An air distribution nozzle and fluidized bed including said nozzle, the nozzle including a gas inlet pipe and an air distribution cap defining a space inbetween them, first air outlet means allowing air to flow from the gas inlet pipe to the space and second outlet means allowing air to flow from said space to the ambient area, wherein said second outlet means has an outer cross section along the outer surface of the cap that varies in its vertical height along its horizontal extension.

A fluidized bed system includes a first nozzle group that is provided inside a fluidized bed furnace, a second nozzle group that is provided inside the fluidized bed furnace, a first supply section that supplies a gas into the fluidized bed furnace through the first nozzle group, a second supply section that supplies the gas into the fluidized bed furnace through both the first and second nozzle groups, and a control section that controls the second supply section during a start-up operation to supply the gas into the fluidized bed furnace to form a fluidized bed of a fluid medium inside the fluidized bed furnace, and stops the supply of the gas by the second supply section and controls the first supply section during a normal operation to supply the gas into the fluidized bed furnace to form the fluidized bed of the fluid medium inside the fluidized bed furnace.

A fluidized bed system includes a first nozzle group that is provided inside a fluidized bed furnace, a second nozzle group that is provided inside the fluidized bed furnace, a first supply section that supplies a gas into the fluidized bed furnace through the first nozzle group, a second supply section that supplies the gas into the fluidized bed furnace through both the first and second nozzle groups, and a control section that controls the second supply section during a start-up operation to supply the gas into the fluidized bed furnace to form a fluidized bed of a fluid medium inside the fluidized bed furnace, and stops the supply of the gas by the second supply section and controls the first supply section during a normal operation to supply the gas into the fluidized bed furnace to form the fluidized bed of the fluid medium inside the fluidized bed furnace.