DE1945179B - Refractory building material for ladle linings - Google Patents

Description

3 ° 4

The object of the invention is to provide a building material of the material according to the invention as a function

to create the type mentioned at the outset, which as a stamping of various factors, such as. B. the type and

mass can be processed - which is of course its use- Form of the special components used,

dung in the form of shaped stones does not exclude - vary.

is compatible with basic slag and in its 5 For example, the mixture can be in the following

Lifetime (number of batches) moving in competitive areas:

should be. Parts by weight

According to the invention, this object is thereby achieved by refractory batch particles 40 to 95

solved that on the particles of the granules before- Kyanite 0 to 20

lying refractory materials first a phosphorus graphite 2 to 40

phate coating, on top of it a coating of binding clay, far: binding clay 2 to 30

another graphite coating and another phosphate 1 to 15

Phosphate coating is applied. The making of water 1 to 15

Building material can be done according to the invention so that

those coated with the first phosphate binder coat

seen granules with in relation to their grain materials and with optimal properties has the following

greetings fine binding clay are mixed that according to the following composition:

Formation of the binding clay coating of the mixture graphite parts by weight

flakes are added and that the mixture after fired slate 64.0

Formation of the graphite coating again a phosphate 20 kyanite 5 2

binder is added. The result is a Norwegian graphite ....... '. .. δ ', 9

Ready-to-use, flowable (pourable), in the refractory binding clay 10.3

Material easily pounded into the pan. Let it be aluminum phosphate 6.5

pointed out that from the ÜSA.-Patent Wasser 5.1

3,285,763 a refractory ramming mass is known per se 25

which, however, is not flowable (pourable), but rather baked slate, which is the preferred fire plastic and therefore more difficult to process. In addition, solid base material for the construction according to the invention it differs significantly in its ingredient, is made from refractory slate, The composition of the building according to the invention is a hard or flint-like refractory clay substance, in particular it does not contain graphite. 30 and occurs as an unstratified massive rock,

In a preferred embodiment, the particular lack of natural plasticity, and refractory ladle lining material according to which showing a shell-like fracture. This material Invention on the basis of fairly coarse, is burned or calcined to his own made of refractory support material, which can be removed from shrinkage, and then on the geMaterials, like baked shale, clay, 35 desired particle size broken. A typical one Zirconia, silica or silica, chrome ore and chemical analysis for calcined or calcined Mullite, can be selected. The first on the fire-slate shows the following composition: Solid carrier material applied coating is aluminum phosphate or another phosphate, such as content in%

Phosphoric acid. After applying the phosphate 40 clay. _; 44.37

The mixture particles are coated with silicon dioxide 51.89

sought materials, such as binding clay and kyanite or titanium 2.67

a similar material, coated. The phosphate, ferric oxide 0.73

Binding clay and kyanite form the matrix or carrier calcium oxide .. 0.05

mass that the refractory base materials contain- 45 Magnesium oxide 0.11

closes and the gaps and pores between its alkali constituents 0.38

Particle fills. Then a coating is made

Graphite applied to which another phosphate- The particle sizes of the refractory base material Protective layer follows. The graphite is highly refractory, although it is not a critical factor preventing it the adherence of iron and slag 50 is generally between 0.15 and 6.75 mm, where on the lining and mainly contributes to the greater proportion between 0.3 and 6.75 mm, desired properties of the mixture. A typical grain size analysis of calcined Graphite, however, is suitable for use in the invention at temperatures of about shale 1100 ° C, as they prevail on the surface of the lining as follows: slightly oxidized. This oxidation would be the 55th

Properties of the lining, which the graphite has to- Grain size (mm) Sieve residue in ° / "

are to be attributed, such as the ability to an adhesion of 6.75 0.0

To prevent iron and slag from destroying. From 4.75 14.7

for this reason the coating is made of a phosphate 3.40 18.0

provided over the graphite. The phosphate also has 60 2.40 9.3

the function, of the refractory mix its strength 2.00 5.3

Speed up to about 65 ° C below the melting point to 0.85 11.6

keep. Aluminum phosphate e.g. B. is at increased 0.60 13.4

Temperatures most elastic, gives a production 0.42 14.0

nis with an excellent resistance 65 0.30 5.3

against chipping and sudden temperature changes - 0.21 3.3

and ensures a high level of strength. 0.15 2.3

The composition of the. Pan Ausklcidungs- sieve passage at 0.15 2.8

1

It should be noted that the above grain size distribution contains two distinct groupings, one with relatively large particles and the other with a concentration of fine particles. The medium sized ones Particles between these two groups are kept to a minimum. This particular one Combination of particle sizes is such that the large particles collide and the fine particles Particles fill the gaps without pushing the large particles apart. Such an arrangement in Combination with an appropriate division of the proportions of large and small particles results in an end product high density, which is desirable to prevent penetration of the molten metal and slag to withstand in the refractory lining.

The kyanite is a desirable component of the mixture because it expands in volume ^{when heated to over 1100 ° C.} This expansion takes place at roughly the same temperature at which the binding clay begins to shrink, so that any gaps or pores that may otherwise arise are filled. The kyanite also reacts with the liquid phase, which ^{begins to appear at temperatures above about HOO 0} C, forming a more viscous glass pntti ?. These factors all improve the load-bearing capacity of the material when it is hot. The kyanite also contributes to the fire resistance of the matrix or carrier, which has the lowest melting temperature of the ingredients in the final product. Other natural aluminum silicate refractories that expand when heated can be used in place of the kyanite, such as andalusite and sillimanite, although these materials do not expand as much as kyanite.

The kyanite is preferably broken raw Virgin'a kyanite, an aluminum silicate mineral with approximately of the following chemical composition:

Salary in ° / o

Alumina 56.3

Silica 41.5

Titanium 1,2

Ferric oxide 0.8

Calcium oxide 0.1

Magnesium oxide 0.1

A suitable grain size analysis for the kyanite has the following data:

Grain size (mm) sieve residue in%

0.85 0.0

0.6 0.1

0.42 7.8

0.3 15.7

0.21 31.1

0.15 22.2 ,,

0.1 10.7

0.075 6.6

0.05 3.9

Sieve passage at 0.05 1.9

The term "binding clay" used here is intended to those Include materials that have high bond strength and are capable of the other connect non-plastic components with one another. The binding clays can be selected from fabrics be that have this ability to bind. The most common group of binding clays are plastic or refractory binding clays. Others 179

'6

Examples include bentonite and plastic materials containing kaolinite such as kaolin.

A preferable binding clay is a kaolinite type plastic refractory clay which is typical of the following chemical analysis has:

Salary in ° / ₀

Alumina 41.57

Silica 53.96

Titanium 2.15

Ferric oxide 1.38

Calcium oxide 0.09

Magnesium oxide 0.17

Alkali constituents 0.64

This binding clay is dried and there ι so far Grind so that it passes through a DIN 1.5 sieve. Kaolin can be used for less pure kaolinite refractory clays, if a refractory binder or material is required. The binding clay in the mixture has the task of to fill the gaps between the refractory batch particles and the refractory mixture Plasticity and adhesiveness and to give the mass cohesion at the elevated temperatures.

The preferred graphite used in the invention is Norwegian graphite, one in Norway natural material to be found. The graphite-containing mineral is broken and the graphite through Flotation separated from gangue, dried and classified as follows:

Grain size (mm) Sieve residue in% 0.85 0.0 0.6 0.1 0.42 0.6 0.3 5.0 0.21 13.6 0.15 21.2 0.1 21.6 0.075 17.4 0.05 5.0 Sieve passage at 0.05 15.2

The carbon content of the resulting material is approximately 90% · This particular Norwegian Graphite is preferred because of its large-spotted structure and its relative softness as well as because of its resistance to oxidation in contrast to other artefacts Graphites.

The coating of the refractory base material with the various coatings is carried out in such a way that the particles do not adhere to one another and also do not form a sticky mass instead of the desired separate, flowable particles. This is achieved by using a pelletizing device, preferably with an inclined, rotating plate. Such a device is sold, for example, by the Dravo Corporation under the name "Dravo-Lurgi" pelletizing disk or disk. With such a device, the pellet size can be adjusted by monitoring the speed of rotation, the angle of inclination and the feed point. The classification effect of the plate or the disc according to the particle size layers the particles on the bottom of the trough or pan and delivers the finished pellets continuously in pinan cpiir »f · ™«

Size range. The plates or disks also allow the operator to manipulate the materials during to observe the pelleting process. These pelletizing discs require little maintenance and work nevertheless with high throughput rates.

The mixture is prepared by first adding the baked slate or other bulk refractory material weighed and conveyed to the surface of the inclined disk of the pelletizer which at a speed of about 18 rev / min. rotates at an angle of inclination of 45 °. A Aqueous slurry is formed from the aluminum phosphate, and a portion is added to that on the circulating Sprayed disc rolling refractory mix. The binding clay is then fed onto the rotating disc and adheres to the binder coating already present on the refractory mixture particles. The kyanite and graphite are then similarly coated onto the particles. The rest the aluminum phosphate water slurry is then sprayed onto the particles on the disc for Formation of the upper protective coating over the graphite. After a short tumbling time of about ίο 3 minutes on the disc, the material that is not agglomerated and still in separate particles present, discharged from the disc, conveyed to a packing device and in multi-walled, polyethylene-coated Packed in bags or boxes.

Some typical properties of the refractory material produced are listed below:

Clay

Silicon dioxide ...

Ferric oxide

titanium

Calcium oxide
Magnesium oxide.
Alkali constituents
Burning losses ...
humidity

Chemical Analysis after

Deliver

36.27

41.96

0.69

1.98

0.07

0.09

0.34

13.80

5.80

dried

38.50

44.49

0.73

2.10

0.08

0 _; 10

0.36

13.64

burned

43.16 49.87 0.82 2.36 0.09 0.11 0.40 Physical properties

Investigative ° / o linear Modulus of rupture
space Modulus of rupture
at temperature change temperature Temperature, ° C kg / cm ¹ kg / cm ¹ 110 -0.2 41.3 ___ 540 -0.2 38.5 - 815 -0.2 21.0 23.8 1100 -0.3 21.0 33.95 1260 - 0.2 24.5 7.56 1370 + 0.6 26.6 3.92 1480 + 0.8 25.9 2.38 1600 + 1.0 28.0 1650 + 1.2 56.7 -

The contact angle between the molten slag and the molten metal and the refractory particles coated with graphite is high, which prevents wetting and capillary impregnation of the lining by the molten components. This leads to a low chemical attack on the refractory lining. The thermal conductivity of the lining is low, and the molten metal does not solidify easily and also does not form a pan residue in the pan due to the non-wettability of the building material, which is able to withstand sudden temperature changes without chipping and has a high strength over the usual temperature range in order to withstand the impact of the molten metal stream occurring the first time it enters the empty ladle. The refractory building material also shows little shrinkage. One of the particularly salient features of the ladle liner refractory material of the invention is its flow consistency and the fact that it is in the form of discrete particles which, once removed from the package, can be easily conveyed to a form in the ladle such as on a vibratory conveyor. The refractory building material is then tamped down according to the shape of the pan, forming a tight, non-porous lining. Neither special shapes nor any cutting operations are required, as is otherwise the case with linings made up of individual stones; but of course, the material can also for molding of refractory bricks find use, where it is then brought into the desired shapes, and dried at a temperature of about 260 ⁰ C.

The special components and ingredient η and the process for producing the refractory building material allow the incorporation or inclusion of graphite with an elastic protective coating for the purpose Prevention or retardation of the oxidation of graphite. The wear and tear of the lining material also progress comparatively slowly. The fireproof building material dries easily and does not tear open when drying, nor do blisters appear. The modulus of rupture under different conditions is also high, as stated above, resulting in high resistance Erosion at operating temperatures results.

209546/41

2697

Claims (3)

Patent·! - h mass or shaped bricks made of refractory materials i-atentansprucne. ^ Additive graphite Such a building material is from the 1. Refractory building material for casting ladles - Publication »Consultation room for ceramics, glass.Email«, clothes in the form of rammed earth or form 1960, p. 53, known, the graphite chamotte shaped bricks from refractory materials with graphite bricks describes while from the publication Addition, characterized in that "Feuerfestkunde" von Harders / Kienow, 1960, refers to the particles of p. 539/540 present in granules, a ramming compound for ladle lining fire-proofs Materials initially a phosphate gene is known, which however as less durable than that Coating, on top of which is a coating of binding clay, also referred to as fireclay bricks that are therefore preferable another coating of graphite as well as an additional one will be. This reference insists on the one-time phosphate coating is applied. Required care when lining the ladle 2. Refractory building material according to claim 1, marked, which would otherwise only have a low durability is characterized by a composition from about and lead to deterioration in the quality of the cast 40 to 95 parts by weight of refractory aggregate can. or base material, 1 to 15 parts by weight of Phos- 15 In fact, the requirements for ladle phat binders, 1 to 15 parts by weight of water, linings problematic. As the most important property 2 to 30 parts by weight of graphite and up to 20 stores are required: parts of a natural aluminum silicate, .. ,, ..,,, _A ~ _,. · η w such as kyanite, andalusite and sillimanite. ^L resistance to attack and reaction 3. Refractory building material according to claim 1, da- 20 ^with molten slag characterized in that the refractory material 2. Resistance to attack by molten baked slate as the base material, steel, is turning. 3. Resistance to sudden changes in temperature 4. Refractory building material according to claim 3, what would otherwise lead to premature failure characterized in that the phosphate is an aluminum 25 and inclusions in the cast metal minium phosphate is used. could lead, and 5. Refractory building material according to claims 1 4, low thermal conductivity,
to 4, characterized in that as a refractory Basic material alumina (AI ₂ O ₃ ), zirconium oxide (ZrO ₂ ), the residence time of the molten steel in the casting Quartz, chrome ore and mullite as well as panning 3 ° as a binder is usually relatively short, which Kaolin or bentonite are used. too steep temperature gradients over the fire 6. Method of manufacturing the building material after solid lining leads. This makes it impossible to establish claim 1, characterized in that the granules in contact with the molten metal with any kind of equilibrium near the first phosphate binder coating have an interface in relation to their grain size 35. For example, to be mixed in fine binding clay is that after forming a 19 cm thick pan lining the temperature of the binding clay coating of the mixture graphite is added at a distance of about 2.5 cm from the interface in the case of flakes and that the mixture has an initial steel temperature of about 1580 ° C after after formation of the graphite coating added again a few minutes only about 260 ⁰ C and reaches phosphate binder. 4 ° only about 650 ° C after 1 hour. 7. Method of making a refractory Most steel comes with a basic slag Building material mix, especially produced for rammed, and it would therefore seem logical that Ladle linings and the like according to claim 6, the ladle lining would also be basic. It characterized by the following process steps: however, no basic refractory product was used a) Use of fired slate ^4S particles can be added, which had the required resistance with a particle size between 0.15 and sudden temperature change in order to avoid the 6.75 mm, sudden and extreme temperature changes. b) Sprühen'eines slurry or Aufschläm- ^ ruchung when filling and during emptying of mung of aluminum phosphate and water pan withstand, as mentioned Literaturauf Schiefertonteilchen the purpose of coating ⁵ ° ^ste "f" refractory customer "is removed of the particles Due to the lack of a suitable basic fire ...... ' , ~, _Ri solid material have the steelmaker Applicable methods c) Mixing one of the group of refractory and _{acidic refractory} materials, such as refractory binding clay and kaolin, fireclay bricks, forced. Although the Erweichungsmit a maximum particle size up to _pun kt this stone materials is so low that its about 16 mm with the coated particles for _{use in such} environments the envelope mt the ball clay, appears to be ruled out, making the short encryption d) Mixing graphite with a particle dwell time and the abovementioned abrupt temperature size of at least 0.3 mm to the particle gradient, their use is possible. However, the use of process _{steps c) and 6o of firebricks} has different consequences e) Addition of further aluminum phosphate parts compared to monolithic or tamped ones and water slurry to the particles of decay linings, e.g. B. the need for more special step d) for producing the outer shaping and cutting work. Another one with a Scha protective cover over the graphite layer. The problem associated with mottestones is sealing 65 of the joints between the stones to prevent the ingress of molten metal The invention relates to a refractory building material and slag, as a result of which they are dimensionally stable required for ladle linings in the form of rammed stones.