AT406056B - METHOD AND INSTALLATION FOR THE PROCESSING OF IRON AND OIL-CONTAINING RESIDUES - Google Patents

Description

AT 406 056 B

Process and plant for processing iron and oil-containing metallurgical residues

The invention relates to a method for processing iron and oil-containing metallurgical residues, in particular mill scale, and for recycling the iron and oil-containing metallurgical residues in a melting and / or reduction unit, and a plant for carrying out the method.

A method of this type is known for example from DE 101 584 A1. After adding molasses and calcium hydroxide, mill scale is briquetted as a binder and reused in the steelmaking process. This process is complex and expensive.

From DE 727 576 C1 it is known to produce fine-grained iron-containing by-products from steelworks and metallurgical plants, such as blast furnace gas dust, blast furnace gas sludge, roll sinter and the like. Like with

Mixing alumina cement as a binder and gravel, lime or slag as an additive, forming it into pieces and using it in the blast furnace. The lime serves as a limestone only as a non-reactive aggregate. This process is also expensive.

A method for recycling oil-containing mill scale, which is similar to the method described in DE 4 101 584 A1 and also has its disadvantages, is also known from US Pat. No. 4,585,475. Here, oil-containing mill scale is mixed with a binder, such as a mixture of molasses and calcium hydroxide or a mixture of sodium silicate and Portland cement, the mixture is agglomerated and the agglomerates formed are used in a molten steel bath. If necessary, iron oxide fine particles are also mixed into the mill scale.

A disadvantage of these known processes is that in addition to lime, in the form of limestone or calcium hydroxide, another binder must be added in any case in order to apply the appropriate binding forces for agglomeration.

From US 5 505 903 A a process for the production of briquettes from magnetitic material and haematitic material is known in which the magnetitic material is mixed with the haematitic material and then a binder such as molasses or slaked lime is added and the mass thus obtained is cold formed.

WO 96/06955 A1 describes the formation of agglomerates from metallurgical dusts containing metal sulfates, lime and water being added to the dusts. It is essential here that the metallurgical dusts containing metal sulfates are at least partially water-soluble. According to WO-96/06955 A1, in addition to the metallurgical dusts containing metal sulfates, leaching residues can also be processed, for example.

The object of the invention, while avoiding a thermal deoiling route, is to improve and further develop these known processes in such a way that complete and yet very economical processing of the iron and oil-containing metallurgical residues and recycling in a smelting and / or reducing unit by admixing only of a single binder is made possible. In particular, the method according to the invention should be able to be implemented with only low investment costs.

This object is achieved in that the iron and oil-containing metallurgical residues, if necessary after admixing other oil-containing fractions, such as Waste oil, mixed with quicklime, preferably quicklime, and that the free-flowing fraction formed, if necessary after an intermediate treatment, is introduced into the melting and / or reducing unit.

A method for binding oils present in water (motor oils or other waste oils) or liquid chemical waste materials in order to render them harmless with quicklime is known, for example, from AT-335 375 B. What is essential in this process is that the quicklime becomes hydrophobic, as a result of which the oil or the liquid chemical waste materials are finely dispersed in the pretreated lime and can be placed in a landfill.

A process for the disposal of mineral oil-containing wastes and sludges, in which a water-repellent reaction product which can be used as a substructure material is formed, is known from AT-367 088 B. According to this document, mineral oil-containing material is sprinkled with a lime-containing reagent, whereby a fine-grained, water-impermeable 2

AT 406 056 B

Is obtained reaction product that can be used as a building material.

According to the iron and oil-containing metallurgical residues are preferably with an amount M (wt .-%)

M = (AxF + BxG) + C mixed on quicklime, where - A depends on the reaction temperature and the residence time during mixing and preferably from a range from 1.0 to 3.0, particularly preferably from 1.5 to 2, 5, is selected, - F is the residual moisture in% by weight, - B is dependent on the properties of the quicklime, the type of oil and the residual moisture and is preferably selected from a range from 0.1 to 0.5, - G the Oil content in% by weight, and - C is dependent on the reactivity of the quicklime and the residual moisture and is preferably selected from a range from 0 to 5.

The iron and oil-containing metallurgical residues are preferably processed with a residual moisture content of 5 to 15%.

According to a preferred embodiment of the process according to the invention, the free-flowing fraction formed from the iron and oil-containing metallurgical residues and from quicklime, if necessary after comminution, is mixed with other metallurgical residues, in particular dusts from dry filter systems and / or sludges from wet washing, and the mixture formed in this way is agglomerated. The agglomerates formed in this way are introduced into the melting and / or reduction unit, if appropriate after drying.

According to a further preferred embodiment, the free-flowing fraction formed from the iron and oil-containing metallurgical residues and from quicklime, if appropriate after comminution, is blown into the melting and / or reduction unit, preferably with a grain size of < 5 mm.

Advantageously, the free-flowing fraction formed from the iron and oil-containing metallurgical residues and quicklime is first sieved, a coarse and fine fraction of the free-flowing fraction being obtained.

The fine fraction, especially with a grain size < 5 mm, is preferably blown into the melting and / or reducing unit.

According to another advantageous embodiment of the method according to the invention, the fine fraction, in particular with a grain size < 5 mm, initially mixed with other metallurgical residues, in particular dusts from dry filter systems and / or sludges from wet washing, and the mixture formed in this way is then agglomerated. The agglomerates formed in this way are introduced into the melting and / or reduction unit, if appropriate after drying.

The coarse fraction is preferably introduced directly into the melting and / or reducing unit.

The coarse fraction is expediently used, in particular with an oil content < 0.2%, introduced into a sintering device and inserted into a blast furnace by the sintering device.

According to a further preferred embodiment of the process according to the invention, the iron and oil-containing metallurgical residues are together with other metallurgical residues, in particular dusts from dry filter systems and / or sludges from wet scrubbing and optionally other oil-containing fractions, such as e.g. Waste oil, homogenized and mixed with quicklime, the mixture thus formed is agglomerated, and the agglomerates thus formed are introduced into the melting and / or reduction unit, if appropriate after drying.

A plant for carrying out the process according to the invention is characterized in that a first mixer for mixing iron and oil-containing metallurgical residues and optionally other oil-containing fractions, such as e.g. Waste oil, with quicklime is provided and that the first mixer is connected to a melting and / or reducing unit.

According to a preferred embodiment, a comminution device, in particular a grinding device, for comminuting the free-flowing 3 is connected to the first mixer

AT 406 056 B

Group provided.

The comminution device is advantageously connected to blowing devices, in particular with blowing lances, for blowing the comminuted free-flowing fraction into the melting and / or reducing unit.

A further mixer is expediently provided after the comminution device, into which a feed line for other metallurgical residues, in particular for dusts from dry filter systems and / or for sludges from wet scrubbing, opens out, and then an agglomerating device for agglomerating the mixture formed in the second mixer at the second mixer and then, if necessary, a drying device thereafter.

According to a further preferred embodiment, a sieving device for sieving the free-flowing fraction is provided next to the first mixer, from which a discharge for a fine fraction and a discharge for a coarse fraction originate.

The discharge line for the fine fraction is preferably connected to blowing devices, preferably blowing lances, for blowing the fine fraction into the melting and / or reducing unit.

According to a further preferred embodiment, the discharge for the fine fraction opens into a further mixer, into which a feed line for other metallurgical residues, in particular for dusts from dry filter systems and / or for sludges from wet scrubbing, also opens, and an agglomeration device is connected to the second mixer for agglomeration of the mixture formed in the second mixer and, if appropriate, a drying device subsequently provided thereafter.

The discharge for the coarse fraction expediently opens into the melting and / or reducing unit.

It is also advantageous if the discharge for the coarse fraction opens into a sintering device, which in turn is connected to a blast furnace.

According to yet another preferred embodiment of the system according to the invention, a feed line for other metallurgical residues, in particular for dusts from dry filter systems and / or for sludges from wet scrubbing, opens into the first mixer and is then an agglomeration device for agglomerating the in the first mixer to the first mixer formed mixture and then optionally provided a drying device.

The invention is explained in more detail below with reference to the drawing, the process flow diagrams shown in FIGS. 1 and 2 showing preferred embodiments of the invention.

According to Figure 1, iron and oil-containing metallurgical residues 1, such as mill scale, optionally together with other oil-containing fractions, such as Used oil, mixed with quicklime 3 in a first mixer 2, for example a ploughshare mixer. The required amount M (% by weight) of quicklime 3 depends on the residual moisture of the material to be processed and on its oil content, further on the reaction temperature and residence time in mixer 2, on the type of oil and on the reactivity of quicklime 3. The quicklime 3 serves on the one hand as a dispersion carrier for oil, which is converted into a finely dispersed phase, and on the other hand as a binder for the production of thermo-shock-resistant agglomerates in the event of agglomeration, and also for reducing the moisture content.

The required amount M of quicklime 3 is preferably calculated according to the following formula:

M = (AxF + BxG) + C

In the above formula, A is a factor dependent on the reaction temperature and the residence time during mixing for the required amount of quicklime 3. A is preferably from a range from 1.0 to 3.0, particularly preferably from a range from 1.5 to 2.5, chosen. F is the residual moisture of the material to be processed in% by weight. In general, there is the connection that less quicklime 3 is required at a higher reaction temperature, since a larger proportion of moisture evaporates, which does not have to be bound by quicklime 3. In addition, less quicklime 3 is required the longer the mixture remains in mixer 2, since moisture evaporates longer and the moisture percentage drops. 4th

AT 406 056 B B is a factor dependent on the properties of quicklime 3, the type of oil and the residual moisture of the material to be processed and is preferably selected from a range from 0.1 to 0.5. G is the oil content in% by weight. If quicklime 3 is very fine and easily dispersible for oils (i.e. easily wettable), little quicklime 3 is required and the factor B is small. In general, the factor B is chosen larger for a higher oil content, but smaller for a higher residual moisture. C depends on the reactivity of the quicklime 3 and the residual moisture of the material to be processed and is preferably selected from a range from 0 to 5. If quicklime 3 has poor dispersion behavior or reacts sluggishly, a higher factor C is selected. A high factor C is also required if the material to be processed is very dry. Without additional addition of quicklime 3, there is too little binder for subsequent agglomeration to achieve sufficient mechanical strength.

For example, a mill scale fraction has a moisture content of 10% by weight and an average oil content of 5% by weight. This mill scale fraction is mixed with quicklime 3 of good quality with regard to the dispersion behavior and the hydration reaction, etc., the reaction temperature being about 70 ° C. and the residence time in the mixer being 2 minutes. The factors A, B and C are chosen in this example with A = 1.5, B = 0.2 and C = 1, so that the required amount M of quicklime 3 is M = 1.5x10 + 0.2x5 + 1 = 17% by weight quicklime results.

The processing of mill scale can also advantageously be carried out if the material to be processed is puncture-proof. Since a certain proportion of binder, that is to say a certain amount of quicklime 3, is definitely required, the advantageous consistency of the mill scale to be processed is in the range from 5 to 15% residual moisture. However, the processing of iron and oil-containing metallurgical residues 1 with a residual moisture lying outside this range also poses no problems.

A free-flowing, oil-dispersed, dry fraction is formed in the mixer 2 by adding quicklime 3 to the iron and oil-containing metallurgical residues 1. This free-flowing fraction 4 can be processed in various ways.

According to an embodiment variant shown in FIG. 1, the free-flowing fraction 4 is comminuted in a comminution device 5, for example a grinding device, preferably to a grain size of less than 5 mm. This comminuted free-flowing fraction 4 can be blown directly, for example by means of blowing lances, into a melting and / or reducing unit 6, for example a blast furnace 6a, a converter 6b or an electric arc furnace 6c.

When blowing into the melting and / or reducing unit 6, dispersed hydrocarbons, i.e. the dispersed oils used as energy suppliers and the quicklime 3 as a slag generator.

However, the free-flowing fraction 4 can also be combined in a second mixer 7 with other non-oil-containing metallurgical residues 8, in particular with dusts from dry filter systems and / or with sludges from wet scrubbers. Such sludges and dusts include, for example, converter dusts and sludges, blast furnace dusts and sludges, dusts from electric arc furnaces, etc. Before mixing with other metallurgical residues 8, it may be necessary to comminute the free-flowing fraction 4 by means of the comminution device 5. The mixing ratio of the individual metallurgical waste fractions in the second mixer 7 results mainly from the amounts of the metallurgical residues and their chemical composition.

Following the formation of a homogeneous mixture in the second mixer 7, an agglomeration process, such as pelleting, briquetting or extrusion, is carried out in an agglomerating device 9. The agglomerates formed in this way are introduced into the melting and / or reducing unit 6 in a manner known per se. Before the agglomerates are introduced into the melting and / or reducing unit 6, drying of the agglomerates can advantageously also be provided in a drying device 10. The agglomerates are preferably dried to a moisture content of less than 5%. 5

Claims (21)

AT 406 056 B It may be necessary to screen a fine fraction 11, advantageously with a grain size of less than 5 mm. This fine fraction 11 can either be blown into the melting and / or reducing unit 6 or be recycled for new processing, advantageously into the first mixer 2. According to one embodiment variant shown in FIG. 1, the free-flowing fraction 4 is removed by means of a screening device 12 a fine fraction 11 and a coarse fraction 13 separated. The coarse fraction 13, e.g. Rolling scale flakes, which have a grain size of greater than 5 mm, for example, are either introduced directly into the melting and / or reducing unit 6 or, if their oil content is less than about 0.2% by weight, fed to a sintering device 14. The coarse fraction 13 can then be returned from the sintering device 14 to a blast furnace 6a. The fine fraction 11, which for example has a grain size of less than 5 mm, is either directly, e.g. by means of blowing lances, blown into the melting and / or reducing unit 6, or, as described above, mixed with other metallurgical remnants 8, agglomerated and introduced into the melting and / or reducing unit 6 in this way. According to an embodiment shown in FIG. 2, the iron and oil-containing metallurgical residues 1 are homogenized in the first mixer 2 together with the other metallurgical residues 8 and mixed with quicklime 3, optionally with the addition of water. The mixture formed in this way is fed to the agglomerating device 9, and the agglomerates thus formed are in turn introduced into the melting and / or reducing unit 6. Here, all iron-containing dust and sludge fractions occurring in a metallurgical plant with and without oil content are combined in one step into a single mixture of substances and agglomerated by adding quicklime 3. The invention is not limited to the embodiments stiffened in the drawing. For example, it is also possible to agglomerate the comminuted free-flowing fraction 4 or the fine fraction 11 from the screening device 12 without further admixing of other metallurgical residues 8 and to introduce it into the melting and / or reduction unit 6 in this way. Furthermore, the process variants described above can be used in combination if required (e.g. very large amounts of metallurgical residues). In the line connections between the individual treatment stations (e.g. mixer 2, screening device 12, etc.) are, if necessary. Intermediate bunker provided. Claims: 1. Process for processing iron and oil containing metallurgical residues (1), in particular mill scale, and for recycling the iron and oil containing metallurgical residues (1) in a smelting and / or reducing unit (6), characterized in that the iron and oil-containing metallurgical residues (1), if necessary after admixing other oil-containing fractions, such as Waste oil, with quicklime (3), preferably quicklime, are mixed, and that the free-flowing fraction (4) formed in this way, optionally after an intermediate treatment, is introduced into the melting and / or reducing unit (6). 2. The method according to claim 1, characterized in that the iron and oil-containing metallurgical residues (1) with an amount M (wt .-%) M = (A x F + B x G) + C of quicklime (3) are mixed , A being dependent on the reaction temperature and the residence time during mixing and preferably being chosen from a range from 1.0 to 3.0, particularly preferably from 1.5 to 2.5, F being the residual moisture in% by weight. %, B is dependent on the properties of the quicklime (3), the type of oil and the residual moisture and is preferably selected from a range from 0.1 to 0.5, G is the oil content in% by weight, and 6 AT 406 056 BC depends on the reactivity of the quicklime (3) and the residual moisture and is preferably selected from a range from 0 to 5. 3. The method according to claim 1 or 2, characterized in that the iron and oil-containing metallurgical residues (1) are processed with a residual moisture content of 5 to 15%. 4. The method according to one or more of the claims 3, characterized in that the free-flowing fraction (4) formed from the iron and oil-containing metallurgical residues (1) and from quicklime (3), optionally after comminution, with other metallurgical residues (8) , in particular dust from dry filter systems and / or sludges from wet scrubbers, is mixed so that the mixture formed in this way is agglomerated, and that the agglomerates thus formed are introduced into the melting and / or reduction unit (6), if appropriate after drying. 5. The method according to one or more of claims 1 to 3, characterized in that the free-flowing fraction (4), optionally after comminution, formed in the smelting and from the iron and oil-containing metallurgical residues (1) and quicklime (3) / or reducing unit (6) is blown in, preferably with a grain size of < 5 mm. 6. The method according to one or more of claims 1 to 3, characterized in that the free-flowing fraction (4) formed from the iron and oil-containing metallurgical remnants (1) and from quicklime (3) is first sieved, a fine (11 ) and coarse fraction (13) of the free-flowing fraction (4) is obtained. 7. The method according to claim 6, characterized in that the fine fraction (11), in particular with a grain size < 5 mm, is blown into the melting and / or reducing unit (6). 8. The method according to claim 6 or 7, characterized in that the fine fraction (11), in particular with a grain size < 5 mm, is initially mixed with other metallurgical residues (8), in particular dusts from dry filter systems and / or sludges from wet washing, that the mixture formed in this way is then agglomerated, and that the agglomerates thus formed, if appropriate after drying, are and / or reduction unit (6) can be introduced. 9. The method according to one or more of claims 6 to 8, characterized in that the coarse fraction (13) is introduced directly into the melting and / or reduction unit (6). 10. The method according to one or more of claims 6 to 9, characterized in that the coarse fraction (13), in particular with an oil content < 0.2%, is introduced into a sintering device (14) and is used by the sintering device (14) in a blast furnace (6a). 11. The method according to one or more of claims 1 to 3, characterized in that the iron and oil-containing metallurgical residues (1) together with other metallurgical residues (8), in particular dusts from dry filter systems and / or sludges from wet scrubbing, and optionally other oil-containing fractions , such as Used oil, homogenized and mixed with quicklime (3), that the mixture formed is agglomerated, and that the agglomerates thus formed, if necessary after drying, are introduced into the melting and / or reduction unit (6) (Fig. 2) . 12. Plant for performing the method according to one or more of claims 1 to 11, characterized in that a first mixer (2) for mixing iron and oil-containing metallurgical residues (1) and optionally other oil-containing fractions, such as e.g. Waste oil, with quicklime (3) is provided and that the first mixer (2) is connected to a melting and / or reducing unit (6). 13. Plant according to claim 12, characterized in that a comminution device (5), in particular a grinding device, is provided for comminuting the free-flowing fraction (4) to the first mixer (2). 14. Plant according to claim 13, characterized in that the comminution device (5) with blowing devices, in particular with blowing lances, for blowing the comminuted free-flowing fraction (4) into the melting and / or reduction unit (6). 7 AT 406 056 B 15. Plant according to claim 13 or 14, characterized in that a further mixer (7) is provided after the shredding device (5), in which a feed line for other metallurgical residues (8), in particular for non-oil-containing dusts from dry filter systems and / or for Sludge from wet scrubbers, flows out, and that an agglomerating device (9) for agglomerating the mixture formed in the second mixer (7) and, if appropriate, a drying device (10) is then provided after the second mixer (7). 16. Plant according to one or more of claims 12 to 15, characterized in that a sieving device (12) for sieving the free-flowing fraction (4) is provided next to the first mixer (2), from each of which a derivative for a fine fraction ( 11) and a derivation for a coarse fraction (13) starts. 17. Plant according to claim 16, characterized in that the discharge for the fine fraction (11) with blowing devices, preferably with blowing lances, for blowing in the fine fraction (11) in the melting and / or reduction unit (6) is connected. 18. Plant according to claim 16 or 17, characterized in that the discharge for the fine fraction (11) opens into a further mixer (7), in which a feed line for other metallurgical residues (8), in particular for dusts from dry filter systems and / or for sludges from wet laundry, and that an agglomerating device (9) for agglomerating the mixture formed in the second mixer (7) and, if appropriate, a drying device (10) is then provided after the second mixer (7). 19. Plant according to one or more of claims 16 to 18, characterized in that the discharge for the coarse fraction (13) opens into the melting and / or reduction unit (6). 20. Plant according to one or more of claims 16 to 19, characterized in that the discharge for the coarse fraction (13) opens into a sintering device (14) which in turn is connected to a blast furnace (6a). 21. Plant according to claim 12, characterized in that in the first mixer (2) opens a feed line for other metallurgical residues (8), in particular for dusts from dry filter systems and / or for sludges from wet laundry, and that then to the first mixer ( 2) an agglomerating device (9) for agglomerating the mixture formed in the first mixer (2) and then optionally a drying device (10) is subsequently provided (FIG. 2). Including 2 sheets of drawings 8