DE977255C - Process for the production of highly refractory molded bodies - Google Patents

Description

Process for the production of highly refractory moldings The invention relates to a process for the production of highly refractory, cold-bonded molded bodies from mixtures of sintered magnesite and heavy metal slags with certain grain sizes and proportions.

It is known that the grain size distribution of the feedstock is of essential importance for the properties of refractory materials. For example, from the German patent specification 748222 a method for the production of highly refractory magnesite bricks is known in which ground sintered magnesite from "fine grain" (o to ioo i,), "medium grain" (ioo to iooo. R,) and "coarse grain" (over iooo w) in a ratio of 2o to 4o: 15 to 25: 35 to 65 with the addition of 2 to 6% aluminum oxide or substances that supply or contain it. If necessary, the mixture can be processed into cold-bonded magnesite bricks using binders, including water glass. The use of heavy metal slag does not take this method into consideration.

It is also known to produce refractory molded bodies from slag. It is known from "Chimie et Industrie", 29 (r933), p. 481, from the Production of ferrochrome resulting slag directly with refractory molded bodies about 20 to 40% chromium oxide, 18 to 30% magnesium oxide, 25 to 45% aluminum oxide and 8 to 14 "/ o other ingredients to be poured. Also one has already ground out Slag cold-bonded refractory molded bodies produced, for. B. after the British Patent 210 708 made of ferrotitanium slag.

Finally, there are also refractory materials that are made of magnesite and Slags of the above Art are known. So .will according to the German patent specification 75o 654 a granular sintered material for production of magnesite or chrome magnesia stones produced by a mixture of finely divided Magnesia and 15 to 50% chrome ore, calculated on the total amount, under assessment the silica content of the mixture, based on the calcined state, to 3 to io% "of the ferrous oxide content to less than 12% and of the lime content to less than 3010, is sintered. Here, chrome ore can be wholly or partially in the raw mixture due to slag rich in chromium spinel - these include ferrochrome and aluminothermic vanadium slags - to be replaced.

So it will not be the manufacture of the finished refractory products itself, but the production of the starting materials for this is described. Find it There is no information about the grain size distribution in the raw material mixture or in the for the further processing of the sintered material to be ground, the type of production of molded bodies from this. It remains to be seen whether this is manufactured in the manner described To process sintered goods alone or together with aggregates into refractory bodies is and how the bond is to be achieved here. This well-known teaching offers hence no basis for comparison with the present invention, its essence it concerns precisely these features not touched there.

According to the invention, it is possible to produce highly refractory, cold-bonded ones Moldings, which are characterized by particularly good pressure fire resistance and thermal shock resistance distinguish. These advantages are achieved without the fire resistance and the Slagging resistance decrease significantly.

According to the invention, a mixture of the following components is used: 2o to 4o parts by weight of titanium, vanadium, chromium, molybdenum, tungsten or manganese slag or several of these slags with a grain size greater than 3 mm, preferably 6 to 3 mm (coarse grain); 20 to 50 parts by weight of such slag with a grain size of 3 to 0.18 mm (fine grain); 2o to 4o parts by weight of sintered magnesite with a grain size below 0.18 mm (flour).

This mixture is in a manner known per se with 4 to 9 percent by weight a water glass solution (d = 1.350) and mixed with water until it is deformable, deformed (e.g. into stones or linings) and at temperatures of up to 200 ° C dried. This is when setting occurs.

The slag used in the thermite process and the used in the electrometallurgical reduction resulting slag.

In modification of the method of operation described above, if corresponding special properties of the finished product are required, too Mixtures are used in which the coarse grain fraction or the fine grain fraction or both up to 75 percent by weight of their total amount of sintered magnesite Grit included. In this embodiment, 25 to 90 percent by weight are expedient and preferably 5o weight percent slag in the coarse and / or fine grain.

In any case, the flour portion consists entirely of sintered magnesite.

It has proven to be particularly advantageous to use a mixture of slags of different mineralogical structures and different compositions as slag. Example 1 Two manganese slags of composition i. S102. . . . . . . :. . . . . . . . . . . 1.5 to 3.5 per cent. A1203. . . . . . . . . . . . . . . . . . 61 to 63 0/0 Fe 203. . . . . . . . . . . . . . . . . . I up to 2.5 0/0 Mn304 ................. io up to 1q.0 / 0 Ca0 ... ... . ... . . ... . .. 14 to I60 / 0 Mg0 .................. 5 to io% Ba0 ........ .. _ ...... to I0 / 0 2. S102 ............... .... 0.5 to 1.5% Al 203. . . . . . . . . . . . . . . . . . 65 to 72 0/0 Fe 203 .. ... ...... . . . . .. I, 5 to 2% Mn, 04. . . . . . . . . . . . . . . . . 16 to 220/0 Ca0. . . . . . . . . . . . . . . . . . . i to 4.5 0/0 Mg0. . . . . . . . . . . . . . . . . . z to 7% Ba0. . . . . . . . . . . . . . . . . . . up to 1.5% are mixed in equal parts, broken up and sieved to grain sizes 6 to 3 mm and 3 to 0.18 mm. These fractions are mixed with sintered magnesite powder in the following ratio: manganese slag mixture 6 to 3 mm. . . . . . . . . . . . . . 3o to 35 '/ o 3 to 0.18 mm. . . . . . . . . . . 35 to 40% magnesite flour. . . . . ... . . . . . 2o to 300/0 As magnesite flour, ground sinter from natural or artificial magnesites can be used, with the use of a low-flux seawater magnesite showing particularly good results: s i02. . . . . . . . . . . . . . . . . . . . . 0.99-1 / 0 A1203. . . . . . . . . . . . . . . . . . . . 0.300 / 0 Fe203 .................... 0.06% Ca0. . . . . . . . . . . . . . . . . . . . . 2.350 / 0 Mg0. . . . . . . . . . . . . . . . . . . . '96.27' / o This mixture is mixed with 5 to 9 percent by weight, preferably 5 to 6 percent by weight of water glass (d = 1.350) and the amount of water necessary for deformability and compacted into stones by shaking, pressing or tamping and a heat treatment for several hours at ioo Subject to up to 20o ° C.

The stones obtained in this way have one opposite the normal one cold-bonded magnesite brick improved pressure fire resistance and Resistance to temperature changes and are in terms of fire resistance above Seger cone 38.

Example 2 The manganese slag mixture of grain sizes 6 to 3 mm and 3 to 0.18 mm mentioned in Example i is mixed together with corresponding grain sizes of comminuted magnesite chunks and magnesite flour in the following ratio: Magnesite 6 to 3 mm. . . . . . . . . . . . . . . . . . . 12.5 0/0 Manganese slag mixture 6 to 3 mm. . . . . . . . . . . . . . . . . . . 12.5 0/0 Magnesite 3 to 0.18 mm. . . . . . . . . . . . . . . . 25.0010 Manganese slag mixture 3 to 0.18 mm. . . . . . . . . . . . . . . . 25.0q / 0 Magnesite flour. . . . . . . . . . . . . . . . . . 25, o-% This mixture is processed further, as indicated in Example i, preferably with 6 to 7 percent by weight of water glass.

The stones obtained in this way have hardly any reduced resistance to temperature changes and pressurized fire compared to the stones according to Example i. However, they are higher in terms of fire resistance, namely above Segerkegel 4.o. Example 3 Comparative tests were carried out with industrial slags of the following compositions: i. With a chrome slag of the following composition: Si02 ............ ..... 25% A1203 .................. 22% Fe203. . . . . . . . . . . . . . . . . . 3 0/0 Cr203. . . . . . . . . . . . . . . . . . 13 '/ o Ca0 ................... 50/0 M90. . . . . . . . . . . . . . . . . . 32 0/0 2. With a manganese slag of the following composition 5102 ................... 2% A1203 ................ .. 620/0 Fe203. . . . . . . . . . . . . . . . . . 3 0/0 Mn304. . . . . . . . . . . . . . . . . 20010 Ca0 ................... 8% Ba0 ................... 3% Mg0 .... ............... 20/0 3. With a vanadium slag of the following composition: si02 ................... 20/0 A1203 ...... . . . . . . . . . . . . 75 0/0 Fe203. . . . . . . . . . . . . . . . . . 10/0 V205. . . . . . . . . . . . . . ..... 3010 Ca0. . . . . . . . . . . . . . . . . . . i 0/0 Mg0 ................... 18% These slimes, drawn off in the liquid state, were poured into blocks. From this, the following test specimens were produced in test series A, B and C: A. Test specimens cut or drilled out of the solidified blocks (these specimens therefore correspond to stones cast in molten state).

B. Cold-bonded cinder blocks, which are made from 32% coarse grain (6 to 3 mm), 40 "/ o fine grain (3 to 0.18 mm) and 28% slag powder. The mixture was made up with about 6% water glass (d = 1.35) as a binder and then at 2ooo C dried.

C. Cold-bonded cinder blocks, which are made of 320/0 coarse grain (6 to 3 mm), 40% fine grain (3 to 0.18 mm) and 28% magnesite flour. The mixture was again made up with about 6% waterglass (d = 1.35) as a binder and then dried at 200 ° C. The cinder blocks accordingly correspond to the present one Invention.

The thermal shock resistance of the test specimens produced in this way for A, B and C was each determined in several parallel tests according to DIN 1068 (cylinder method). The test results, which each reflect the average value of a series of individual tests, are summarized in the following table: Ver number of deterrents kind of at u s series of the test specimen chromium-manganese! Vanadium slag slag slag A Drilled out 3 io 3 Melting body B Cold bonded 9 25 16 Stone with Slag meal C Cold bonded 16 47 21 Stone with Magnesite flour The test results show an increase in the resistance to temperature changes from the melt body (A) to the cinder block (B), which is not surprising in itself because the compact molten body without pore space cannot behave as favorably as a cold-bonded stone with a grain structure.

However, the further increase in thermal shock resistance is completely surprising for cold-bonded stones with a flour content made of magnesite.

In the context of the present invention, element protection is neither for the grain size distribution still for the use of heavy metal slag in Compound with sintered magnesite claimed.

Claims (3)

PATENT CLAIMS: i. Process for the production of highly refractory moldings from finely divided mixtures of sintered magnesite and heavy metal slag, thereby characterized in that a mixture of 2o to 4o parts by weight of titanium, vanadium, chromium, Molybdenum, tungsten or manganese slag or more of these slags with one Grain size over 3 mm, preferably from 6 to 3 mm (coarse grain), 2o to 5o parts by weight Such slag with a grain size of 3 to 0.18 min (fine grain) and 2o to 4o parts by weight Sintered magnesite with a grain size below 0.18 mm (flour) in a manner known per se after adding 4 to 9 percent by weight of a water glass solution (d = 1.350) and of Water formed until deformable and dried at temperatures of up to 2oo ° C will. 2. Modification of the method according to claim i, characterized in that Mixtures are used in which the coarse grain or the fine grain or both up to contain 75 percent by weight of their total amount of sintered magnesite of the corresponding grain size. 3. The method according to claim i or 2, characterized in that a mixture of slags of different mineralogical structures and different compositions is used. Considered publications: German Patent Specifications No. 750654, 748222, 592 748; German patent applications p 38593 VIb / 8ob D (published on November 20, 195o), D 5o67 VIb / Bob (published on July 26, 1951); Austrian Patent No. 108 773; British Patent No. 21o 7o8; U.S. Patent No. 1645,030; Reports of the DKG, 1930, pp. 56/57; Z. f. Chimie et Ind., 29/2 (1933), pp. I81.