Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B13/00—Making spongy iron or liquid steel, by direct processes
  • C21B13/0006—Making spongy iron or liquid steel, by direct processes obtaining iron or steel in a molten state
  • C21B13/0026—Making spongy iron or liquid steel, by direct processes obtaining iron or steel in a molten state introduction of iron oxide in the flame of a burner or a hot gas stream

Definitions

• the present invention relates to a method and a device for the direct production of liquid iron, starting from oxidic iron compounds
• processes are known in which the raw materials are first converted into sponge iron using suitable gases and then melted in a metallurgical vessel, the thermal energy in the melting vessel being caused by the reaction of oxygen-containing gases with carbon-containing substances, which are primarily blown in under the bath surface , and carbon monoxide are formed.
• the heat is partly used to melt the sponge iron and the exhaust gas is used for the direct reduction of ores.
• the entire exhaust gas must first be treated with coal dust and water vapor in a separate reactor.
• an additional heating is provided in a.
• Combined melting and gas generation reactor by reacting a fuel with oxygen, a reducing gas is produced, which is directed in a subsequent reduction room in counterflow to an ore feed, while the pre-reduced ore obtained at the end of the reduction stage is conveyed into the heated melting and gas generation room, where it is melted and melted is then freshened up - as part of another process that focuses on direct production of pig iron, two separate feed or reaction zones are provided in the smelting and gas generating reactor. In a first zone, a carbon carrier is fed directly to a molten metal in order to maintain a carbon content which is preferably above 2%.
• part of the carbon bound to the melt is burned by means of oxygen, releasing heat and reducing gases.
• a carbon lance supplied is used here on the detour via an intermediate carburization of the iron bath essentially to increase the melting capacity of the bath and to form reducing gases.
• This process provides for saturating an iron bath with carbon by blowing in a carbon carrier using a neutral or reducing carrier gas, forming a cone of iron ore over the surface of the bath and blowing oxygen onto the edge zones of the bath. during which the bath is flushed with a neutral gas from below through at least one blow stone arranged in the bottom of the vessel.
• the latter has the effect that the composition of the gases produced when oxygen is blown onto the carbon-saturated iron bath can be effectively controlled, and if one intends to use the exhaust gases to pre-reduce ore, an exhaust gas which is virtually 100% CO can be used with a high reduction potential through targeted oxygen supply with reduced flushing.
• a hard oxygen blowing method will be preferred and the purging of the bath with inert gas will be limited to 0-0.1 Nm3 / t.hour.
• an intensive purging of the bath with inert gas can promote afterburning of the carbon monoxide formed on the surface of the bath, which takes place under intense heat.
• the amounts of purge gas are then preferably between 0.1-0.3 Nm3 / t.hour.
• the additional heat development occurring on the bath surface can be used to melt the iron ore applied there.
• the aim of the invention was therefore to propose a process for the production of liquid iron which, on the one hand, includes a material supply which allows long-term contact between the substances and which on the other hand has a high degree of flexibility, in particular what the possibility of a rapid change of gaseous and solid material or of mixtures allowed.
• the new process should not require expensive and large-scale devices and should avoid the unnecessary consumption of gases and solids.
• an iron melt is given oxygen on the one hand by inflation from above and on the other hand gases and solids suspended in gases, primarily iron oxides and carbon-containing substances. as required, individually and in combination, feeds from below through one and the same charging unit, the latter essentially consisting of a refractory vessel bottom stone, which is provided with oriented passages such that they are gas-permeable at the same time without permitting the passage of liquid metal and that both the gas supply and the solids supply are switched on as required, controlled in terms of quantity and interrupted.
• the heat supply to the bath itself is controlled by continuous or intermittent inflation of oxygen accomplished.
• the blowing on the bath surface is not hindered by the presence of molten and freshly applied iron ore.
• the ideal solids composition understands around 70% Fe203 and 30% C, where the finely ground substances are preferably stored separately and only mixed when they are actually fed into the bath before they pass through the feed unit.
• This also understands the measure that one takes into account the chemical reactivity of the gases or solids, as well as the thermal conditions within the melt, in that endothermic gases or solids are introduced into the melt with the help of such charging units, those below hotter ones Bath zones are arranged and that if any exothermic gases or solids are used, the procedure is reversed.
• carbon will preferably be introduced into the center of the vessel, since the bath is hotter there.
• the invention offers a decisive advantage, namely that fine-grained iron ore is available in large quantities and at relatively low prices.
• the reason for this is the fact that the cheap transportation of ores by means of pipe services requires that the ores are in the finely ground state, the mean grain size being around 50 u.
• This in turn has the consequence that the ores which have been transported cheaply have to be converted again according to the prior art into a form which permits their further metallurgical processing, which means that the ores have to be pelletized before their further processing. Pelleting is because you have to burn the pellets. a relatively expensive affair, so that the profits made by cheap transport are lost again as a result of the inevitable conversion of the ores into pellets.
• these disadvantages are not only avoided, but are turned into a clear advantage.
• the device required to carry out the method according to the invention essentially understands a converter for fresh iron, which is equipped with an oxygen inflation lance and in the bottom of which several charging units are arranged.
• Each loading unit understands a refractory, gas-permeable structure which consists of at least two on longitudinal surfaces, made of fireproof unbaked, e.g. segments bound with a carbon carrier or chemically bound material is constructed.
• These segments are provided with a wear-resistant support on at least one longitudinal surface and are combined by a common metal housing that lies tightly against the longitudinal surfaces of the segments, possibly with the interposition of a layer of mortar, with at least one connection and a distribution space for the on an end surface of the structure Material supply are arranged and the connection is connected to at least one gas and at least one solid feed device, each of which understands a metering device.
• the dosing device for solids is usefully a per se known cellular wheel blow-through lock as the applicant e.g. in their Luxembourg patent LU 80.-692.
• gas-permeable structures which are provided in accordance with the prior art for supplying gases into liquid metals and as described by the applicant in her Luxembourg patents LU 82.552, 82.553, 82.554 and 82.597 are used for the combined introduction of gases and solids, which is made possible by coupling the building structure to solid feed devices which are also known but are used in other contexts.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Carbon Steel Or Casting Steel Manufacturing (AREA)
• Manufacture Of Iron (AREA)

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Citations (12)

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• 1981
  • 1981-04-22 LU LU83313A patent/LU83313A1/de unknown
• 1982
  • 1982-03-24 EP EP82630023A patent/EP0063532A1/fr not_active Withdrawn
  • 1982-04-21 US US06/370,501 patent/US4469510A/en not_active Expired - Fee Related
  • 1982-04-21 JP JP57065557A patent/JPS57181310A/ja active Pending

Patent Citations (12)

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