Metallurgical apparatus – Means for melting or vaporizing metal or treating liquefied... – By means introducing treating material
Reexamination Certificate
1999-06-02
2001-06-12
King, Roy (Department: 1742)
Metallurgical apparatus
Means for melting or vaporizing metal or treating liquefied...
By means introducing treating material
C266S226000, C266S268000, C266S270000
Reexamination Certificate
active
06245285
ABSTRACT:
The present invention relates to a lance.
The present invention relates particularly, although by no means exclusively, to a lance that can be used in a metallurgical vessel on a continuous or batch basis and withstand substantial exposure to molten metal and slag in the vessel that could chemically attack the lance and substantial variations in temperature in the vessel that could contribute to premature mechanical failure of the lance.
The present invention relates more particularly, although by no means exclusively, to a lance that can be used in a range of operational positions to inject solid feed materials into a metallurgical vessel which contains a bath of molten material having a layer of molten metal and a layer of slag with or without a mixture of molten metal and slag. The range of operational positions includes, but is not limited to, positions in which the tip of the lance is:
i. above the bath in a clear or splash zone;
ii. immersed in the slag layer; or
iii. immersed in the metal layer.
The present invention relates more particularly, although by no means exclusively, to a method of injecting solid feed materials into a metallurgical vessel that is based on the use of a lance of the present invention.
The present invention relates more particularly, although by no means exclusively, to a lance that can be used to carry out the HIsmelt process for producing molten iron with top injection of solid feed materials, such as coal, iron ore, and fluxes, to penetrate the surface of a bath of molten iron/slag in a metallurgical vessel.
There is a wide range of known lances and tuyeres for injecting solid feed materials into metallurgical vessels for producing ferrous and non-ferrous metals and alloys. The known lances and tuyeres include, by way of example:
i. The SAVARD-LEE bottom tuyere for the injection of oxygen through the refractory lining of metallurgical vessels. The tuyere comprises at least 2 concentric pipes. Typically, in use, oxygen is injected through the inner pipe and hydrocarbons (as coolant) are injected through the annular space(s) between the pipe(s). This type of tuyere is also used for injecting solids entrained in a carrier gas instead of oxygen (Z-Bop, KS, KMS). Kortec AG has patented several particular concentric pipe combinations of the tuyere which, in use, are cooled by hydrocarbon mixtures with water and a carrier gas. These combinations have been used in a wide range of applications. However, in general, the tuyere is sensitive to burn-back and erosion of refractories around the tuyere. Typically, the burn-back velocity (and associated refractory erosion) is between 0.5 and 1.5 mm/hr. This rate of refractory loss limits tuyere life.
ii. Kortec AG has also patented a horizontally or vertically movable tuyere with similar characteristics to the tuyere referred to in item i. The concentric pipes of the tuyere in this case are fixed in a round refractory sleeve and the resultant assembly of the sleeve and the pipes is progressively pushed into a metallurgical vessel to compensate for burn-back. By this method, erosion of refractories is minimised.
iii. Inclined top lances, particularly for electric arc furnace applications, for the injection of oxygen, coal, and other solids. These lances are water cooled and in a furnace operation are moved into a slag layer but are kept away from the molten metal layer to ensure that there is minimal contact with molten metal. Typically, the lances have a limited lifetime of 500-2000 heats (200-800 operational hours) before repairs and maintenance are required.
Other known lances and tuyeres include, but are not limited to Sirosmelt lances, Ausmelt lances and steal pipes (and refractory coated steel pipes) used in the iron and steel industries for injecting gas and solids.
However, notwithstanding the wide range of known lances, the applicant is not aware of a lance that is capable of withstanding substantial exposure to molten iron and substantial long term and continuous temperature variations as would be required in order to be used in the HIsmelt or similar process when operated with top injection of feed materials.
An object of the present invention is to provide a lance that is capable of operating under these conditions.
According to the present invention there is provided a lance for injecting a feed material, preferably a solid feed material, into a metallurgical vessel, which comprises:
i. an inlet for introducing the feed material into the lance;
ii. an outlet at a forward end of the lance for discharging the feed material from the lance;
iii. a hollow elongate member that defines a passageway for the feed material between the inlet and the outlet and is adapted to be cooled by a first cooling fluid; and
iv. an outer jacket positioned around a section of the length of the member and is adapted to be cooled by a second cooling fluid.
In use, the jacket and the second cooling fluid that flows through the jacket acts as a shield for the enclosed section of the length of the member and prevents direct damage to this part of the member that could be caused by contact with molten metal and/or slag and minimises adverse effects of high temperature and variations in temperature along the length of the member. In addition, in use, the first cooling fluid that flows through the member protects the member from adverse effects of the high temperature environment:
(i) externally of the member, including where the member extends beyond the jacket at the forward end of the lance; and
(ii) internally of the member in situations where the feed material is preheated.
It is preferred, although by no means essential, that the member be tubular.
It is preferred that the member extend beyond the jacket at the forward end of the lance.
It is preferred that the member comprise at least one passageway for the first cooling fluid.
It is preferred that the member comprise an inlet for introducing the first cooling fluid into the cooling fluid passageway and an outlet for discharging heated first cooling fluid from the cooling fluid passageway.
It is preferred that the cooling fluid passageway outlet be in the region of the forward end of the lance.
It is preferred that the cooling fluid passageway be in the form of an annular chamber.
It is preferred that the first cooling fluid comprise a mixture of water and a gas, such as nitrogen or carbon monoxide or argon.
The first cooling fluid may also comprise one or more other gases that, in use, are of benefit in a metallurgical process.
It is preferred that the lance further comprises a means for atomising water in the water/gas mixture.
It is preferred particularly that the atomising means be located at the inlet of the cooling fluid passageway.
It is preferred that the member have two or more of the cooling fluid passageways for the first cooling fluid.
With such an arrangement, it is preferred particularly that the cooling fluid passageways be concentric annular chambers.
It is preferred that the member comprise an outer wall and an inner wall and that one of the annular cooling fluid chambers be between the outer wall and the inner wall.
With such an arrangement, it is preferred that the other or one of the other annular cooling fluid chambers be an annular gap between the outer wall of the member and an inner wall of the jacket.
It is preferred that the lance further comprises a means for supporting the member so that the member can move relative to the jacket in the lengthwise direction of the lance.
It is preferred that the lance further comprises a means for moving the member relative to the jacket to compensate for erosion of the member at the forward end of the lance and thereby maintain initial relative positions of the jacket and the member at the forward end of the lance.
It is preferred that the jacket be positioned around a section of the member that is at the forward end of the lance.
It is preferred that the jacket define a chamber for the second cooling fluid.
It is preferred that the chamber be closed at the forward end of the lance.
It is preferred particula
Bates Cecil Peter
Dry Rodney J.
Weber Margot
Weber Ralph M.
King Roy
McGuthry-Banks Tima
Merchant & Gould P.C.
Technological Resources Pty. Ltd.
Weber Margot
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