DE1059942B - Process for the enrichment of iron melts with manganese in a cupola furnace - Google Patents

Description

GERMAN

A non-prepublished proposal is aimed at iron melts from ferrous feedstocks to melt in a preferably neutral or basic lined cupola furnace, which with an amount of fuel in excess of the normal rate - e.g. B. also of those inferior Quality - and preferably with a hot blast of around 400 ° C and more reducing as a gas generator below Management of a relatively large amount of basic or highly basic slag is operated, wherein in a known manner by z. B. siphon-like drain maintain a high column of slag in the furnace will.

Surprisingly, it has now been found that it is possible by means of this method, the generated Enriching iron melts with manganese if very special conditions are met.

If manganese carriers are added to the species in this process, the invention succeeds the enrichment of these iron melts with manganese in that input materials are included in the charge Such a high Si content - especially in acidic or super-acidic blast furnace smelting processes produced, higher siliconized and sulfur-rich pig iron, which has preferably not been desulfurized is - find use that a partial reduction of the manganese of the slag by the Si content these feedstocks takes place.

In the normal cupola smelting process, there is generally a considerable amount of manganese burnup, whereby the manganese goes into the slag, so that it has not been possible so far, a satisfactory one in the cupola furnace To achieve manganese output.

Several decades ago it was proposed to desulfurize the cast iron produced in the cupola by adding basic Siemens-Martin slag to the batch, because the manganese contained in this slag is relatively easy to reduce and is in a highly reactive form, and because that Manganese in the form of Siemens \ a Martin slag does not cause high costs. In this case, the manganese serves to bind the sulfur in the feed and, above all, the sulfur in the fuel, whereby it migrates with the sulfur as manganese sulfide into the slag. As a result, this is relatively liquid, the consumption of fuel, which may contain high sulfur content, is economical, the attack on the refractory furnace lining being within moderate limits, and the iron is well desulfurized.

In contrast to these previously known methods, a precondition for the method according to the invention is the stove with a hot blast and an amount of fuel exceeding the normal rate

for the enrichment of iron melts
with manganese in a cupola furnace

Applicant:

Rheinstahl iron works
Mülheim / Meiderich Aktiengesellschaft,
Mülheim / Ruhr, Friedrich-Ebert-Str. 100

Dipl.-Ing. Karl Heimberg, Mülheim / Ruhr,

Dr.-Ing. Max Paschke, Aachen,

and Robert Doat, Liège (Belgium),

have been named as inventors

to operate in a reduced manner and to maintain a relatively high column of basic slag in the furnace at all times as well as feedstocks with a high silicon content in the charge, so that it succeeds out the manganese carriers still added to the species partially reduced the manganese to effect the silicon.

Furthermore, it was known that in a cupola furnace operated with a hot blast when using increased Fuel quantities a reducing operation takes place and that then reduction work in the Furnace can be made so that the manganese reduction is increased when manganese-containing ore is added can be. In this prior publication, however, it is expressly recommended due to the reduction of manganese through carbon from the use of higher or siliconized species To take distance. In contrast to this prior publication, the invention relates precisely to the manganese reduction and thus the manganese output in the liquid iron increases considerably increase that in the .Gattierung feedstocks with a high silicon content are used.

On the other hand, it is known in blast furnace operations that, for example, higher-silicon pig iron types can be enriched with manganese by treating this pig iron with liquid manganese-containing slag in the ladle after tapping outside the blast furnace. According to the formula 2 MnOH-Si = SiO ₂ +2 Mn, a manganese reduction occurs due to the silicon of the pig iron, as a result of which the Mn content of the pig iron increases while the Si content is reduced.

909 558Λ99

Claims (1)

Q For the operation of blast furnaces; oderNiederschachV "; furnaces is also a method b * ekanntgeworden, ge ^L measured which metallurgical reactions that performed previously ovens outside this ^ were nunrffehr inv this should ovens take place immediately, and S namely in that below the Einblasedüsen for the bulk of the wind a zone several meters high is maintained, in which the reaction components, which are heated to a high temperature in the mold plane, react with one another before they separate as liquid phases to form various superimposed liquid layers up to 3 m - thickness and preferably only a part of the slag is withdrawn with each tapping, while the other part remains in the furnace. This process, with its extremely thick slag layer, is not possible in the cupola furnace feasible, and otherwise the process according to the invention is not aimed at desulfurization, Dephosphorization, decarburization or deoxidation of pig iron melted from ores in the blast furnace or low-shaft furnace, but it is aimed solely at it, in the basic and reducing operated hot blast cupola apart from the addition of manganese carriers, which is known per se, is even higher or to add highly siliconized starting materials to the charge in order to enrich the cast iron melt to achieve with manganese. In cupola operation, it becomes over the normal rate even with the use of hot blast and one over Excessive amount of fuel does not ensure that there is enough carbon from the feed for the manganese reduction is available. For this it is also necessary that the melting down Iron in a known manner a relatively high column of basic slag of high temperature permeates and that furthermore the ingredients apart from manganese carriers also still so Bring large silicon contents that a partial reduction of the manganese from the slag with the Silicon is produced from the iron with the help of the carbon from the charge, whereby at the same time an excellent desulfurization occurs. Depending on the amount of silicon used an enrichment of the liquid iron with manganese is achieved, whereby of course the manganese reduction a limit is set by the amount of silicon burned. The basicity of the slag goes roughly back, so that it is advisable to use the lime-silica ratio from the outset when adding the mortar substances set relatively high. The type can, for example, when working with coke and limestone from scrap, Si-containing cast iron, ferrosilicon and manganese carriers, such as. B. Siemens-Martin slag, ores containing manganese. The new method is particularly beneficial when more or less large amounts of highly siliconized and sulfur-rich pig iron produced in the acidic or super-acidic blast furnace smelting process are used as iron generic constituents without prior desulfurization, since this iron simultaneously represents a cheap Si carrier and its sulfur content through the desulphurizing effect of the slag plays a subordinate role. For example, by using a siphon-like slag drain, which is known per se, the slag level and the height of the slag column in the furnace are always kept at about the same height or the same layer height, so that a certain amount of liquid, manganese-containing slag is always retained in the furnace, with the inflow of the fresh slag can be regulated by the outflow of the reacted slag. This means that there is always a relatively large amount of slag available for the iron, which allows the iron in the birth state to react with the slag in abundance, with the warming effect of the large amount of slag still having a quality-enhancing effect on the iron. According to the new process, it is possible to remelt both Si-rich pig iron and manganese to enrich and to produce cast iron melts with a higher manganese content with Mn contents above 0.8 or 1%. Furthermore, it is also possible to produce low-manganese iron species by adding manganese carriers to be processed into cast iron melts with a normal Mn content of 0.6 to 0.8. Claim: Process for the enrichment of iron melts with manganese in a preferably neutral • or basic lined cupola, which with a rate exceeding the normal rate Amount of fuel and preferably with a hot blast of about 400 ° C and more under the guidance of a a relatively large amount of basic or highly basic slag is operated in a reducing manner, where the species manganese carriers are added and where by z. B. siphon-like drain a high column of slag is maintained in the furnace, characterized in that in the Generating ingredients with such a high silicon content, especially in acidic or super-acidic blast furnace smelting, higher siliceous and sulfur-rich pig iron, which has preferably not been desulfurized, find use that a partial reduction of the manganese in the slag is due to the silicon content of these feedstocks. Considered publications:
German Patent Nos. 257 686, 611319, 851 412; Stahl and Eisen, 72 (1952), pp. 550 and 552;
Foundry Trade Journal, 89- (1950), pp. 229-232.