LU83921A1 - METHOD OF USING METALLURGICAL SLAG - Google Patents

Description

—I s

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* r -ίο 2112/8202.

s METALLURGICAL RESEARCH CENTER - CENTRUM V00R RESEARCH IN DE METALLURGIE,. Non-profit association - „Vereniging zonder winstoogmerk in BRUXELLES, (Belgium).

Descriptive memorandum formed in support of a patent application for addition to the Luxembourg patent N ° 75.130 filed on June 9, 1976, for a "Method of using metallurgical slag".

The present invention relates to improvements made to the process described in Luxembourg patent No. 75,130 below, said main, and relating to a process for the use of metallurgical slag.

5 \> The metallurgical slag produced by refining a non-phosphorous cast iron according to the process in which industrially pure oxygen is blown into the converter currently finds only very limited outlets, much lower than the quantities available. .

These outlets are essentially, either agronomy, where, because of its high content of caO, this slag (in small quantity) is used to amend the earth, or the discount n to the blast furnace, limited because of the accumulation yb of impurities in the steel cycle that entails - 2 - «·

Ml • »this recycling. The large surplus of unused slag is generally dumped, a solution which still has the disadvantage of requiring expenditure in pure loss, since the material is considered to be irrecoverable.

5

According to the main patent which presents a method of using the aforementioned slag, is added to a liquid slag from the refining with oxygen of a non-phosphorous cast iron, on the one hand, a reducer sufficiently energetic that reduce most of the FeO and MnO of the slag in the metallic state and on the other hand, carriers of alumina and / or silica which give said slag a composition close to that which is usually encountered for Portland cements.

15

The object of this improvement is to specify the operations carried out on non-phosphorous slag, within the framework defined by the main patent, and according to the initial composition of said slag.

20

In case the initial composition of the slag presents

Ca.0 a ratio g £ 0 "whose value is between 2.2 and 4.2, and especially between 2.4 and 3.6 the addition to ef-.

may be limited to an alumina carrier (eg 25 pie of bauxite rich in iron oxide).

/ If the initial composition of the slag presents a report

Ca0 whose value is less than 2.2, the addition of alumina Si02 is supplemented by an appropriate addition of CaO to reach the field of Portland cement compositions. This addition of lime can, however, be advantageous up to a maximum of 2-8 ·

If, on the other hand, the initial composition of the slag has λ a ratio g £ ^ - whose value is greater than 4.2, the addition // of alumina is completed by the addition of silica, in the same *

- I

- 3 - “” aim as above, the two compounds being able to be supplied by the same carrier, for example fly ash from thermal power plants operating on coal. This addition of silica can also be advantageous up to a ratio 5 CaQ., V. 2 g * SiO x # *

It is not beyond the scope of the invention to add, in addition to the slag, fluxing elements (CaF2 * alkalis ...) to make it more fluid. This is also subjected to a reduction operation, for example involving the use of electricity and advantageously in an arc furnace, so that its final content of iron oxide does not exceed 6%, after which the mixture is subjected to air cooling.

15

The additions described above are preferably carried out before the reduction of the iron oxides contained in the liquid mass constituted by the slag plus the additions. They can be produced, for example, in the following ways: - powdery products, such as sand or fly ash: by injection using a lance or by pouring into the furnace, - pebble products such as ferrous bauxite: by pouring, preferably progressive, lime: preferably in the form of impalpable lime, v by means of an injector burner.

Claims (5)

1. Method for using a metallurgical slag from the refining with oxygen of a non-phosphorous cast iron 5 and according to one or other of claims 1 to 6 contained in the main patent, characterized in since the initial composition of the slag having an o xu 2 ratio whose value is between 2.2 and 4.2 and especially between 2.4 and 3.6, the addition to be carried out is advantageously limited to a carrier alumina, preferably ferrous bauxite. 2. Method for the use of a metallurgical slag from the refining with oxygen of a non-phosphorous cast iron and according to one or other of claims 1 to 6, contained in the main patent, characterized in that the initial composition of the slag having a ratio whose value is less than 2.8 and especially less than 2.2, an addition of alumina (advantageously ferrous bauxite) is carried out supplemented by an addition of CaO. 3. Method for the use of a metallurgical slag from the refining with oxygen of a non-phosphorous pig iron and according to either of claims 1 to 6 contained in the main patent, characterized in that the initial composition of the slag having a ratio v 'whose value is greater than 2.9 and above all ^ 4.2, an addition of alumina is carried out (advantageously bauxite rich in iron oxides and sand , or 30 fly ash from thermal power plants) supplemented by the addition of silica. 1 Process according to either of Claims 1 to 3, J characterized in that, in addition to the slag, fluxing elements are added, such as CaF2 # of alkalis___ * - 2 - • k 5. Method according to either of claims 1 to * i ~ 4, characterized in that the mixture constituted by the slag and its additions is subjected to a reduction operation for example ρε electrically, advantageously in an oven with arc, so that the final content of iron oxide mixture does not exceed 6%. 6. Method according to either of claims 1 to 5,. ‘Characterized in that the finished and possibly reduced mixture is subjected to air cooling. __ * / Ç w