A gas injection system for a blast furnace or shaft furnace or metallurgical furnace comprising a furnace wall and a cooling plate wherein the gas injection system comprises a gas distribution pipe, one or more injectors having a nozzle, wherein the nozzle comprises a ceramic insert, wherein the cooling element has a hot side, turned away from the furnace wall, wherein a protrusion is attached to the hot side of said cooling plate, wherein the ceramic insert traverses the furnace wall and the cooling plate and the protrusion on cooling plate and wherein the ceramic inserts have an adaptable length so that they either protrude inside the furnace, or that they are flush with a hot face of the cooling plate or stay slightly in retreat with a hot face of the cooling plate.

A device to inject a reducing gas into a shaft furnace including an external casing whose front face is provided with an outlet for gas injection into the shaft furnace, an internal casing located inside the external casing and made of a steel able to resist to a temperature up to 1200° C., this internal casing having an opening matching the gas injection outlet of the front face of the external casing and a refractory layer located between the external casing and the internal casing.

A device to inject a reducing gas into a shaft furnace includes an external casing whose front face is provided with an outlet for gas injection into the shaft furnace, an internal casing located inside the external casing wherein reducing gas is circulating. The internal casing has an opening matching the gas injection outlet of the front face of the external casing. The front face of the external casing includes an upper and a lower part and the gas injection outlet is in the lower part and inwards from the upper part.

A device to inject a reducing gas into a shaft furnace includes an external casing whose front face is provided with an outlet for gas injection into the shaft furnace, an internal casing located inside the external casing wherein reducing gas is circulating. The internal casing has an opening matching the gas injection outlet of the front face of the external casing. The front face of the external casing includes an upper and a lower part and the gas injection outlet is in the lower part and inwards from the upper part.

A blast furnace for ironmaking production wherein iron ore is at least partly reduced by a reducing gas which is injected in the stack of the blast furnace. The blast furnace includes an external wall, an internal wall in contact with matters charged into the blast furnace, the internal wall including several rows of staves having a parallelepipedal shape. At least one row of staves comprises staves with a hole drilled in a least one of the corners of the parallelepipedal stave wherein an injection device may be partly inserted in.

A blast furnace for ironmaking production wherein iron ore is at least partly reduced by a reducing gas which is injected in the stack of the blast furnace. The blast furnace includes an external wall, an internal wall in contact with matters charged into the blast furnace, the internal wall including several rows of staves having a parallelepipedal shape. At least one row of staves comprises staves with a hole drilled in a least one of the corners of the parallelepipedal stave wherein an injection device may be partly inserted in.

A blast furnace for ironmaking production wherein iron ore is at least partly reduced by a reducing gas which is injected in the stack of the blast furnace. The blast furnace includes an external and an internal wall, having a thickness T.sub.int, in contact with matters charged into the blast furnace. The thickness T.sub.int of the internal wall is substantially constant above and below the injection area of a reducing gas.

A blast furnace for ironmaking production wherein iron ore is at least partly reduced by a reducing gas which is injected in the stack of the blast furnace. The blast furnace includes an external and an internal wall, having a thickness T.sub.int, in contact with matters charged into the blast furnace. The thickness T.sub.int of the internal wall is substantially constant above and below the injection area of a reducing gas.

An air blast system for melting furnaces includes: a supply unit supplying hot air into a melting furnace; a bustle pipe connected to the supply unit; a tuyere stock connecting the bustle pipe to the melting furnace to supply hot air from the bustle pipe to the melting furnace in a distributed manner; and a temperature management module determining whether the tuyere stock is damaged by comparing a temperature of the tuyere stock with a preset reference temperature.

A tuyere comprising an inner tube including a lower section having a first diameter, an upper section having a second diameter smaller than the first diameter, and a converging transition section having a converging angle Θ from 30° to 60° connecting the lower section to the upper section, the inner tube terminating in an inner nozzle at a downstream end of the upper section; and an outer tube surrounding the inner tube so as to create an annulus there between, the outer tube including a lower section having a third diameter larger than the first diameter, an upper section having a fourth diameter smaller than the third diameter but larger than the second diameter, and a converging transition section having connecting the lower section to the upper section, the outer tube terminating in an outer nozzle at a downstream end of the upper section.