DE1257051B - Refractory pulp mixture - Google Patents

Description

GERMAN ^ TWvSsSS PATENT OFFICE

EDITORIAL DEVELOPMENT German Cl .: 80 b-8/15

Number: 1257 051

File number: H 56870 VI b / 80 b

1 2 5 T 051 Filing date: August 13, 1965

Opened on: December 21, 1967

The invention relates to a non-compacted, basic, refractory pulp mixture, which with selected, non-aqueous, carbon-containing binders is bound.

In certain metallurgical processes, the building material steel manufacturing process, which is also sometimes referred to as the LS process, oxygen Bessemer process, oxygen converter process or "Kaldo" process, the basic furnace structure consists of a metal _housing , J0 the one inside having refractory lining, whereby the furnace space is formed in which the method is carried out. In general, the refractory lining of such oxygen steelmaking vessels consists of an inner "working lining" such as B. tar bonded, chemically bonded or calcined, basic stone material, an outer lining, adjacent to the inner wall of the metal casing, usually consisting of burned magnesite stone and an intermediate layer.

The intermediate layer is usually monolithic and is made by e.g. B. a refractory Mass is pulped in situ. The intermediate layer can be different thickness depending of the vessel to be lined and the operating parameters to which the liner is subjected shall be. It was already known that the mass of the intermediate layer consists of a bonded with tar Concentration mixture exists. An example of a previously known tar-bound pulp mixture, which could be described as suitable for the production of this intermediate layer is a dead-burned one Dolomite or magnesite or a mixture of dolomite and magnesite with additives such as B. creosote, furfuryl mass, Pitch, tar or the like. As a binder. When using such pitch additives result there are certain difficulties in arranging the intermediate layer. So has z. B. powdered Binding pitch has a melting point range of 135 to 163 ° C. In order to achieve the required tack, To achieve plasticity and processability in such a pulp mixture, it is necessary to use the To heat products by melting them or in an organic solvent dissolve, and this heated mixture is increased before and during the actual pulping Temperature held.

Some mixtures have been proposed which only operate at a temperature of about 38 to 49 "C must be heated to form a mixture which will work satisfactorily Refractory pulp mixture

Applicant:

Harbison-Walker Refractories Company,
Pittsburgh, Pa. (V. St. A.)

Representative:

Dipl.-Ing. W. Meissner and Dipl.-Ing. Η. Tischer, patent attorneys, Berlin 33, Herbertstr. 22nd

Named as inventor:

Ernest Paul Weaver, Pittsburgh, Pa. (V. St. A.)

Claimed priority:
V. St. v. America September 23, 1964
(398 782),

dated January 14, 1965
(425 619)

can be. However, such a lowest temperature of 38 to 49 ° C can also be difficult to maintain especially during the colder winter months, and thus becomes a tangled one Auxiliary device required for this purpose at the installation site.

What is even more annoying when using some organic solvents, however, is that they tend to become excessively volatile when heated, which creates a risk of explosion in restricted work areas and also irritates the skin of the workers concerned. Some solvents are also poisonous. One object of the invention is thus to create an improved refractory material which leads to the formation of a monolithic product and which is bonded to a non-aqueous, carbonaceous material. Another object of the invention is to create an improved tar-bound, basic, refractory pulp mixture which is particularly suitable for producing the intermediate layer between the outer and inner work linings of a basic oxygen furnace, this material being at room temperature (in the order of magnitude of 21 ⁰ C) is processable, no unsuitable dangerous and toxic properties such as

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1

in the various organic solvents and that nevertheless the desired tack, Has plasticity and processability for the purpose of making it easier to use.

The refractory pulp mixture according to the invention is now characterized in that the same consisting essentially of about 100 parts by weight of the refractory material and 3 to 10 parts by weight of the Binder consists, the binder contains an unsaturated, flowable pitch that is produced during distillation from vegetable oils to remove the fatty acids obtained as residue, the pitch in a sufficient Amount is present in order to impart processability and plasticity to the pulp mixture at room temperature.

The preferred basic, refractory aggregate is selected from the group consisting of dead burned dolomite, dead burned magnesite and occasionally mixtures thereof. It continues occasionally hard-burned calcium oxide in combination with dead-burned dolomite and dead-burned Magnesite applied. In addition to such products as medium pitch, hard pitch and Creosote, the prior art teaches that such carbonaceous materials Avie Bunker-C oil, gilsonite, flaxseed oil, shale tar, asphalt, oil pitch of the kind made by distillation and the cracking of waste, coal, peat, lignite oils can be obtained, with also the use of products such as heavy water gas, light water gas, oil gas, wood tar, certain types of wax and similar products has been recommended.

The invention further relates to a tar-bonded or chemically bonded stone of the type such as it is applicable to the working lining of oxygen steelmaking vessels.

An example of a previously known tar-bound stone is a dead-burned dolomite or magnesite or a mixture of dolomite and magnesite, possibly with the addition of something hard-fired Calcium oxide and additives of creosote, furfuryl mass, pitch, tar or the like as binders.

Difficulties arise in using some types of pitch as additives. So z. B. pulverized wind pitch has a melting point in the order of 135 to 163 ⁰ C. In order to achieve the required stickiness, plasticity and workability of the stone mixture, it is necessary to heat these products by melting them or to dissolve them in organic solvents. This heated mixture is then kept at an elevated temperature before and during the actual deformation of the stone in the stone press.

When working with organic solvents, the difficulties outlined above arise There are also disadvantages in that the volatile components tend to collect in the ventilation systems of the plant.

2 to 10 parts of the binder can be applied, and up to 12 parts can be put into the Work in the stone mixture. The preferred basic refractory aggregate is selected from the group consisting of from dead-burned dolomite (the dead-burned dolomite must be stabilized, i.e. with a dead-burning agent be combined or subjected to a process by which an equivalent stable

ized product is obtained), dead burned magnesite and occasionally mixtures thereof. Occasionally, hard-burned calcium oxide is also used in combination with dead-burned dolomite and applied to dead-burned magnesite.

In addition to hard pitch, medium pitch and creosote are various in the prior art other carbonaceous materials have become known which are used in stone mixtures can. It is further in the selection of different materials of the specified carbonaceous Binder components both for mixtures for the production of monolithic products as Also known are lubricating additives such as petroleum jelly, kerosene, gasoline, benzene and stones to apply similar petroleum products so as to achieve the desired processability, plasticity and / or stickiness to achieve. Such petroleum products naturally lead to a substantial increase in the Risk of explosion and fire. It has also become known, various measuring and dispersing agents use that facilitate the formation of aqueous, colloidal suspensions or emulsions. The person skilled in the art generally knows that water is an unsuitable component in mixtures, consisting of basic, refractory materials, due to the hydration and thereby resulting danger of soot formation.

It has now been found that the desired flowability or processability, plasticity and tackiness can be obtained by either (1) making a tar bonded refractory mixture for preparation of bricks or (2) refractory mixtures for making monolithic products with a suitable Amount of an unsaturated, flowable pitch that is certain after distillation Plant extracts is obtained. These pitfalls belong to that group that is occasionally used in the professional world as "Fettsäurepeche" are called, which is a group name that is generally used for describing the residue obtained from fractional distillation of animal and vegetable products, such as lard, tallow, palm oil and other vegetable products Products, bone fat, waste and sewage, wool fat and slaughterhouse waste is obtained. The residue, known as fatty acid pitch, is usually a dark brown to black, Uniform to lumpy, gritty and thick product that is practically free of saturated Fatty acids is.

The fatty acid pitches used according to the invention are those obtained by distilling linseed extracts and soybean extracts for the production of linseed fatty acids and soybean fatty acids. These products are capable of flowing, in contrast to a wax or soap state at room temperature of about 21 ⁰ C. The linseed pitch has an acid number of 30 to 60, a viscosity (Stormer viscosity seconds at 25 ° C.) of 150 to 350 and an iodine number of 110 to 125. The soybean pitch has an acid number of 30 to 60, a viscosity of 50 to 200 (Stormer viscosity seconds at 20 ° C) and an iodine number of approximately 100 to 110. As indicated by the acid number, there is a significant amount of free fatty acids in both pitches. These pitfalls are occasionally also

Look at their iodine number as "unsaturated" fatty acid pitches. As expected, the Pitches consisting essentially of carbon, hydrogen, oxygen and nitrogen.

According to a preferred embodiment of the invention, about 3 to 3.5 parts by weight of the unsaturated soybean fatty acid pitch and about 2 parts by weight of powdered hard pitch with about 100 parts by weight of basic refractory material, preferably dead-burned magnesite, mixed.

The unsaturated flowable pitches of the present invention can be used in conjunction with either medium or hard powdered pitch. The terms "medium pitch" and "hard pitch" designate two different types of pitch that have different softening points. So softens z. B. the medium pitch at a temperature of 166 to 121 C and the hard pitch at 135 to 221 ⁰ C. Further details regarding such pitches are disclosed in US Pat. No. 3,070,449.

According to a preferred embodiment of the invention, about 3 parts by weight of the unsaturated Flaxseed fatty acid pitch and about 2 parts by weight of the powdered hard pitch with about 100 parts by weight of the basic refractory material, preferably dead burned magnesite, mixed.

A typical size distribution of the refractory aggregate is shown in the following table :

Table I.
Sieve analysis
(expressed in mm clear mesh size)

Particles with 12.7 mm to 3.36 mm approx. 20%

Particles with 3.36 mm to 0.59 mm about 35%

Particles with 0.59 mm about 45%

Particles with -0.59 mm to 0.044 mm .. 40 to 60%

Note: A very small proportion of the material, i.e. H. less than about 5% of the total, based on on the weight of the batch, is submicron in size.

The mixtures according to the invention for making the monolithic product and the stones are distinguished before use in that they have practically no odor. The same feel dry. They have a flowable and somewhat grainy consistency.

When using the preferred monolithic product for the purpose of ramming test pieces the laboratory test surprisingly showed an extraordinary hardness with normal

35 ramming. In one case, a starting point of the product is shoveled into a wooden mold, and if it is tamped in for less than about 5 minutes, the result is such a well-solidified monolithic mass that, with considerable effort, the attempt to pierce a screwdriver into the exposed surface only leads to there is very little damage or breakage of a few larger particles. This pulping is carried out at room temperature of about 21 to 24 ^: C.

If the mixture is e.g. B. processed by means of pulping, results in a not yet complete Understand the selected unsaturated flowable pitch used to the required processability, plasticity and stickiness. It is not necessary to heat the product, around a portion of the powdered hard pitch to make it sticky in solution bring to.

In the laboratory tests, in which an attempt was initially made to find a way to by means of which the inexpedient properties are to be eliminated, as they are, for. B. by creosote and other previously known binder systems are conditioned in a tar-bound pulp mixture, A wide variety of materials have been studied to determine whether a waxy, solid pitch as an ingredient would reduce toxicity. Mixtures are also examined in which unsaturated soybean pitch and other pitches were examined, wherein furfuryl alcohol and flaxseed oil were also used. The addition of waxy solid pitch proves unsatisfactory. The addition of furfuryl alcohol does not lead to such mechanical solid mixture as desired. The mixture along with the flaxseed oil was even mechanically weaker. The unsaturated soybean pitch is much stronger than previously known Mixtures and also leads to good pulping and does not cause any objectionable odor development. In the table below are the results of some of the experimental studies reproduced. It should be noted that the refractory portion of the mixture is a combination of 60% Represents dolomite and 40% magnesite (on a weight basis). The magnesite goes practically completely through a sieve with a mesh size of 0.21 mm, and the entire size classification corresponds practically to the information in the above table I. Wherever dolomite, magnesite or (magnesium oxide), the deadburned products are referred to as they are are customary in the trade.

Table II

1 2 Mixture No.
3 4th 5 Basic aggregate 100% Powdered hard pitch 2% Liquid binder added (such as given below) 3% Liquid binder added 3% 3% 3% 3% 3.5% Furfuryl Soybeans linseed Soybeans Soybeans alcohol bad luck oil bad luck bad luck

continuation

1 2 Mixture No.
3 4th 5 Bulk density mg / cm ³ 2.69 2.79 2.77 2.82 2.84 Load when crushing on the Edge (average 5) room tempera ture of about 21 ⁰ C kg / cm ² 14.7 22.4 13.3 34.3 38.5 Breaking modulus after coking 1600 ° C kg / cm ² (average 2) ... Not checked 13.3 28.0 Remarks : let yourself let yourself let yourself let yourself let yourself bad one good one bad one good one good one stomp, stomp, stomp, stomp, stomp, strong Ge no to be no to be no to be no to be smell after queued queued queued queued Furfuryl the smell the smell the smell the smell alcohol

Mixtures 1, 2 and 3 are compressed under a pressure of 210 kg / cm ² and mixtures 4 and 5 under a pressure of 280 kg / cm ² , and this explains why the moldings of mixtures 2 and 4 are otherwise identical lead to different results in the physical test. Although some of the test pieces were deformed by means of a stone-making machine in order to obtain pieces of practically uniform size, which lead to good comparable physical test results, the explanations regarding the pulping properties relate to additional work that has been carried out with the same mixtures, wherein they were pulped into a mold.

A completely unexpected and useful result of the use of the selected unsaturated fatty acid pitches is the unusually high cold resistance to crushing. B. to compare the mixtures 1 and 3 with the mixtures 2, 4 and 5. The mixtures 4 and 5 compressed at a higher pressure have cold strengths against the crushing of 34.3 to 38.5 kg / cm ² .

The tables also show that 3.5% soybean pitch is significantly better than adding 3% if you want to maintain high temperature strength. The modulus of rupture after a Coking at 1600 ° C, with an increase from 3 to 3.5% of the soybean pitch being slightly more than twice the value of the modulus of fracture. The mixtures according to the invention for the preparation of monolithic products are also characterized by their ability to last for longer periods of time storage, such as B. 1 month long, loose and relatively unconsolidated, and easy to process too stay.

It is stated above that 3 to 8 parts by weight of the total binder mixture per 100 parts by weight refractory material can be used. Up to 10% have proven to be satisfactory proven. A preferred range is 5 to 6 parts by weight per 100 parts by weight refractory material. In any event, it is preferred that the selected fatty acid pitch be 3 to 3.5 parts by weight of the binder mixture, based on the weight of the refractory material, in the manufacture of the invention Mixes for monolithic mixes.

So far, hard pitch has been added to the mixture in order to obtain the largest possible amount of bound To achieve carbon. Since the unsaturated which are used according to the invention Fatty acid pitches do not require a solution of the hard pitch in order to achieve stickiness, graphite or carbon black can also be used as a carbon source. Gilsonite can also be used Find. The total amount of binder,

d. H. 3 to 10 parts by weight based on the total weight of the refractory material can be used and 5 to 6 parts by weight are preferred, but at least about 3 parts by weight of that is selected unsaturated fatty acid pitch, regardless of whether it is a hard pitch, medium pitch, graphite, carbon black or the like constituents of the remainder of the mixture acts. This applies both to the mixtures according to the invention for producing monolithic Products as well as stones too.

Even where little or no bound carbon is required, it is only possible to use the unsaturated fatty acid pitch according to the invention. Furthermore you can where only very little bound carbon is required, a combination with different polymers, such as Acrylic acid compounds, polyamides, polyesters, epoxies and the like for the purpose of achieving a warmth hardening bond.

In general, the refractory unit needs that for preparing the mixtures for monolithic products and applied to stones not to be a basic refractory material. In less critical surfaces of the oxygen converter, such as the intermediate parts and support parts of the liner It is still possible to use basic refractories other than deadburned magnesia, deadburned Apply dolomite and calcium oxide, and so you can, for. B. forsterite, olivine, chrome ore

and the like. The special properties of the binder according to the invention do the same also for use with refractory units, such as calcined fire clays, ganisters, products high alumina, such as diaspore, Alabama and South America bauxite, kyanite, clay and Mullite, suitable. It can be used with mixtures containing silicon carbide and the like and optionally also zircon, zirconia and

contain other generally refractory materials such as those used for making mixtures for making of monolithic products such as pulp mixes and mixes for making refractory bricks are applied.

An example analysis of dead burned dolomite and magnesium oxide as they are used to manufacture of the test pieces according to Table I have been applied is given below:

Table III

Ingredients and compositions are shown in the following Table IV:

Table IV

Magnesite dolomite Silica (SiOo) ... about 2.8% about 1.2% Alumina (AI2O3) about 0.3% about 0.8% Iron oxide (FeaOe) ... about 5.0% Calcium oxide (CaO). about 1.5% about 53.0% Magnesium oxide (MgO) about 94.8% about 38.9%

15th

25th

Above, in particular, the unsaturated, flowable pitches produced by the distillation are given of the fatty acids obtained from flaxseed oil or soybean oil. It goes without saying Of course, that the unsaturated pitch residue is the distillation of fatty acids from other vegetable oils are also satisfactory for the purposes of the invention. The selected flowable Pitch should be characterized by physical properties similar to those given above; H. should be liquid or flowable at room temperature and continue to be highly unsaturated in character (as measured by the iodine number) excel and be able to have the required stickiness, workability and to impart plasticity to the pulp mixture in which such pitches are applied will.

The lowest practical limit for the unsaturated, flowable fatty acid pitch according to the invention amounts to about 3 percent by weight based on the total weight of the refractory product. The upper limit is about 8 to 10% when bound carbon is not important or at least has little importance.

In a way that is not fully understood, the transfer of the invention results Mixture in a stone on a stone press that the selected unsaturated, flowable pitch the overall processability, plasticity and tackiness imparted as required. It's not necessary, to heat the material so as to put some of the powdery hard pitch in solution Achieving the tackiness to convert.

The numerical values according to Table II above (see Mixtures 3 and 4, based on molded bodies) a stone press, explain the physical properties of the stone, which can be produced in the manner according to the invention by means of a stone press.

The technical progress achieved according to the invention is to be compared with that below Subject of US Pat. No. 2,222,188 to be detected, namely by means of comparative experiments. So two approaches were made, their

55

60

VJClll la ^ li
A. Vjciii la ^ -i 1
B. Burned dead Dolomite 9.5 to 1.68 mm .... 30% 30% 1.68 to 0.59 mm .... 30th 30th Magnesite (ball mill fine 40 40 Powdered pitch 2 2 3.5 Unsaturated fatty acid soy bad beans 3.5

Mixture A is prepared using a solid fatty acid stearin pitch according to the United States patent

2 222 188 produced. The mixture B is in the manner according to the invention with an unsaturated Soybean pitch made. Both mixtures are identical with the exception of the two types of pitch specified built up.

Mixture A, ie the mixture containing the fatty acid pitch, had to be heated to a temperature of 93 ° C. before mixing, since the fatty acid pitch is a waxy material at room temperature. The mixture B, ie the mixture containing the soybean pitch provided ^{according to the invention, is heated to 38 °} C., ie only slightly above room temperature, in order to make it easier to deform. Soybean pitch is a viscous liquid at room temperature.

After mixing, both mixtures are left

Stand in sealed containers for 3 days to determine storage properties. After this Storage time shows mixture A, i.e. H. the prior art mixture, the fatty acid pitch contains, a very strong caking and is difficult to break open, but the mixture can B, d. H. easily process the mixture according to the invention containing soybean pitch.

These mixtures are then compressed under a pressure of 210 kg / cm ^{2 in} order to imitate the pulping process. After pressing, both mixtures have approximately the same bulk density. However, the mixture B, ie the mixture according to the invention, is practically twice as strong in the relevant test, which is aimed at crushing the edge of a corresponding shaped body. The properties of these mixtures after compression are given in Table V below:

Table V

mixture mixture A. B. Bulk density g / cm ³ (avg cut 5) 2.76 2.74 Compressive strength on the edge kg / cm ² (average of 152 294

The fatty acid stearin pitch is largely obtained by distilling animal fatty acids,

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Claims (1)

11 12 can, however, also contain pitch that has been obtained by the unsaturated soybean pitch, which is pre-distilled according to the invention of fish oil or vegetable fatty acids, has been obtained by the following experts. This product has the following numbers: the key figures: acid number 20 to 40 5 acid number 50 to 60 iodine number maximum 10 iodine number 100 to 115 Table VI Mixture No. 5 J. Ε. B aker Dolomit Magdolit Jebcolit Magnesite type C (ball mill fines) ... Powdered pitch (liquid binder as specified below) Liquid binder added: Mixture No. 1 Mixture No. 2 Mixture No. 3 Mixture No. 4 Mixture No. 5 Mixture No. 6 Mixture No. 7 Mixture No. 8 Mixture No. 9 3% 1% 1.5% 3% 3% 3% 3% 3.5% 30% 30 40 2 3 Creosote Creosote , 2% fatty acid pitch creosote, 1.5% fatty acid pitch furfuryl alcohol soybean pitch flaxseed oil creosote soybean pitch soybean pitch mixed temperature 0C66 ° C66 ° C Form pressure (kg / cm2) 210 280 123 456 789 Bulk density g / cm3, 572,822 / cm2 , 5 Linear change on coking at 1600 ° C (average 2)% ...- 0.3-0.5-0.5 Modulus of rupture after coking at 1600 ° C (average 2) kg / cm'213,413,428.0 Comments: Mixture No. 1 can be pulped well, strong odor of creosote. Mixture No. 2 can be pulped well, weak creosote odor. Mixture no. 3 can be pulped well, weak creosote odor. Mixture No. 4 is difficult to pulp, strong smell of furfuryl alcohol. Mixture no. 5 can be pulped well, no noticeable odor. Mixture No. 6 is difficult to pulp, no noticeable odor. Mixture No. 7 can be pulped well, strong creosote odor. Mixture No. 8 can be pulped well, no noticeable odor. Mixture No. 9 can be pulped well, no noticeable odor. The advantages of using an unsaturated pitch are clearly substantiated by the numerical values given above. Fatty acid stearic pitch is believed to be impractical because the mixtures processed with it tend to cake in storage and additional work is required to prepare for driving. Furthermore, working according to the invention with an unsaturated pitch in a corresponding mixture leads to approximately double the load capacities compared to the prior art. Patent claims: 1. Non-compacted, basic, refractory pulp mixture, which is mixed with selected, non-aqueous, carbon-containing binders, characterized in that