DE2011805A1 - Process for the production of refractory magnesite chromium and chromium magnesite bricks - Google Patents

Description

1717

Austrian-American Magnesit Aktiengesellschaft in Radenthein / Carinthia, Austria.

Process for the production of refractory magnesite chromium and Ghrommagnesite stones.

The invention relates to a ■ method for producing Refractory magnesite chromium and ear commomagnesite bricks made from a sintered material that is produced by joint firing of chromium oxide-containing Substances and magnesite or other natural or synthetic magnesium compounds that produce periclase in the event of fire, was obtained.

Procedures of this type are in themselves already in large numbers known. In one of these known processes, chromium oxide-containing substances, in particular chromium ore, are optionally mixed with magnesite Sintered magnesite, or other natural or synbhebic, Magnesium compounds which produce magnesium oxide are mixed and, preferably after shaping into briquettes, after burning or stones, at temperatures of at least 1700 ° 0 without melting sintered, whereupon this sintered material, which is usually referred to as simultaneous sintering, grained and, if necessary after adding sintered magnesite, is deformed into stones. That This procedure is characterized by the combination of measures that

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a) for the production of the sintered material lie containing chromium oxide Substances have a grain size of 0 to 6 mm, preferably 0 to 4 mm, with at least 65 / &, preferably at least 80% of the substances containing chromium oxide are present in a grain size of over 0.12 mm,

b) whereas the magnesite or the magnesium oxide supplying substances have a grain size of less than 0.12 mm, preferably at most 0.10 mm, and

c) the sintered material has a silica content of at most 5.5%, preferably 4.5%, and

d) .a lime-silica ratio of at most 0.6, preferably at most O, o5, has.

In a further state-of-the-art technique using a simultaneous sintering material, the rate for the production of the sintered material is reduced to a molar lime-silica ratio of at most 0.6, preferably at most ü, ^ S, and a silica content of the sintered material of at most ^Γ >, ^Γ >Λ>, preferably at most 4.5 / <>, set. In the sintered materials obtained in the two ways mentioned and also in the stones obtained from them, the reriklasteilchen are bound directly to the Ehromoxydhaltlgen particles, and there is thus a so-called direct bond.

* It has now been found that using exit criteria with low kioselic acid ratio for production of the simultaneous sintering material with simultaneous use of the chromium oxide-containing substances in certain grain sizes Magneu Ltehromuriri Ghromniagnesite teins with a direct bond also with molar ones Lime-silica ratios of over 0.6 can be obtained can that compared to the well-known stones from ^ imultanniriterinateriaL an increased resistance to schiakken migration and in particular an infiltration of CaO-rich S c h I a c k ο η a u f w e; i r »en.

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Accordingly, the invention relates to a method for the production of refractory magnesite chromium and chromium magnesite bricks, wherein Chromium oxide-containing substances, in particular chromium ore, in one grain size from 0 to a maximum of 6 mm, preferably a maximum of 4 mm, with fine-grained magnesite, possibly sintered magnesia, or others Fine-grained, natural or synthetic magnesium compounds with a grain size of below 0.20 mm, preferably at most 0.12 mm, the, on the fired Condition related, less than 95%? functional less than 93? »» KgO contain, mixed and, preferably after deformation Sintered to briquettes or stones, at temperatures of at least 1750 ° 0, expediently at least 1850 ° G, without melting are and then this sintered material, which has a content of 5 to 40%, in particular 20 to 30%, Cr-O ^, grained and, optionally after adding sintered magnesia, is shaped into stones. This procedure is in its essence in that

a) for the production of the sintered material at least 20%, at most 80%, the chromium oxide-containing substances have a grain size of have less than 0.12 mm,

b) the sintered material has a silica content of at most 2.5%, a lime content of at most 4% and

c) has a molar lime-silica ratio of over 0.6 to 2.5.

Regarding feature a), it should be noted that in order to fulfill it, it may be necessary, e.g. when using a fraction of chromite or other substances containing chromium oxide from 0 to 2 or 0 to 4 mm, in addition e.g. chrome ore flour of less than 0.12 mm must be added.

The sintering material should preferably have a silica content of at most 1.5%.

So-far away your grained sintered material for the production of If sintered magnesia is added to refractory bricks, such an addition takes place in amounts of at most 35%, based on the

009842/1594

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refractory mixture. When producing unfired bricks using magnesium sulphate as a binding agent, only limited amounts of fine-grained sintered magnesia, namely a maximum of 8 %, preferably a maximum of 3 to 5%, based on the refractory mixture, sintered magnesia with a grain size of 0.12 mm or less may be added to the sintered material will. Any sintered magnesia that may also be added must have a grain size of over 0.12 mm.

The invention is explained in more detail using the following examples:

Example 1: 72% magnesite with a grain size of 0 to 0.12 mm was mixed with 28% Chromers concentrate from 0 to 1 mm, 20 ^r o * flue dust produced when burning magnesite, hereinafter referred to as "flue dust" for short, and 4 Io more saturated Kieserite solution was mixed and the mixture was shaped into briquettes, which were fired at 1850 ° C for about 3 hours in a Kotier or shaft furnace.

The composition of the raw materials and the simultaneous sinter obtained were as follows (the abbreviation "C / S" means the lime-silica weight ratio):

Magnesite chrome ore concentrate simultaneous sintering

SiO ₂ 0.02% 1.89%

Fe ₂ O ₃ 2.99% 15.44%

AIpO ₅ 0.57 V ₀ 14.01 %

Cr ₂ O ',, 0.00% 5'J, 94 %

CaO. 0.57 % 0.07 %

MgO ^l \ ^! \ .85 / o V \ .65%

Loss on ignition 51.00 # + 0.16 % C / S
Grain density

The sintered material was crushed and ground, and 67 '* ■ of this material with a grain size of 0.3 to 5 mm and ^>

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009842 / 15Π

1.01 '.X' 10.16 ¹ 0 6.62 ''O 24.70 / 0 0.84 56.67 + 0.04 \) 0.83 V38 tf / crn- '

3, 23 G 9 g / cm ⁵ 16, 2 C. % 490 G kp / cm 1535 ° 1675 ° > 1700 ° . ο, % 120 kp / cm

With a grain size of 0 to 0.12 mm, with the addition of 1 % dry sulphite waste liquor and 1.6% water they were shaped into stones, which after firing at 1580 ° C had the following properties:

Volume weight (RG)
porosity

Cold compressive strength (KDF)
Pressure fire resistance (DFB) to

ta

decreased hot flexural strength (HBF) at 1260 ° C

Example 2: 72% magnesite with a grain size of 0 to 0.12 mm were mixed with 28% chrome ore concentrate from 0 to 0.5 mm, 20% flue dust and 4% saturated kieserite solution, and the mixture was shaped into briquettes which, at 2000.degree were fired in a rotary or shaft furnace for about 3 hours.

The raw materials and the obtained sintered material had the following composition:

Chrome ore concentrate Simultaneous in t; he

1.03 % 0.97%

28.80% 17.24%

17.65 % 9.52 %

45.95% 25.40 %

0.06% '1.29%

6.51 % 45.58 %

+ 1.67% + 0.14 > / o

• 3.58 g / cm ^

From a. Mixture of 67% of the sintered material with a grain size of 0.3 to 3 mm, 53 % of the3 sintered material with one

Magnesite 3 OK _? 0.05% Fe _? 0. 2.61 % AIpO ₇ 0.20% ^Gr 2 ° 5 0.00 % CaO 1.35% MgO 45.79 % Loss on ignition 50.00% G / S Grain density

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Grain size from 0 to 0.12 mm, 1.1; i dry sulphite waste liquor and 1.8% of water, stones were formed and fired at 1% 0 ° C. The properties of the stones obtained were as follows:

RG ^, 2S g / cm ⁵

Porosity 18.2 -.Ό

KDF 461 kg / cm "

DFB to 1475 ° C

ta 1710 °

ο,

t _B > 1720

decreased 0.6 ο

HBF at 1260 ° C 94 kp / cnT

Example 3 * 72; '& Magnesite with a grain size of 0 to 0.12 mm were mixed with 28 / o chrome rzkona ent rat of 0 to 0.12 mm, 18% fly ash and 4.0 saturated kieserite solution, and the mixture was deformed into briquettes, which were burned in a ^{shaft furnace at 21 r} O ° ΰ for about 6 hours.

The composition of the raw materials and the obtained Sintered material were as follows:

Magnesite Chrome Ore Concentrate SimuLtnnsi riter

SiO ,, 0, 18 '''O o, 6 ¹ S '; o 1, 84 '<■ 18.20 -! Ο AL ₁ O ₅ 0, 1 1 .. 12,70 ^'1 C 0.00 Ό ^l ) S, 04 b Gave 0.80 , υ 0.07 0 MgO 4S, t> 7 ι. ■ H, 12 Vy Loss on ignition ■> 1.40 'Λ) 0.22 ·; .ι c / s

0 48 ■ '" 10 28 L) ^r i 8 ^r > -0 .? 4 7 t-, ι) 0 ^ 4 O 70 0 00 I. ^ b G. ⁷ CIIl 40

! ■ line mixture of t> 7 .ο SiritormaterLaI from 0, ^ to 4 mm, ^ \ o sintered material from 0 to 0.12 mm, 1 ·; ό trvckcnor sulphite waste liquor and 1.8 / α. Vusoer was deformed from stones. which were gobrfinnt at 1 ^ 80 C. These stones had the following oil properties:

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009842/1594

RG 3.20 g / cm ⁵

Porosity 17.0%

KDF 518 ■ kp / cm '

DFB t _B > 1700 ° C

decreased 0.4 %

HBF at 1260 ° G 102 kp / cm '

Example 4: 72% magnesite from 0 to 0.12 mm were mixed with 28% chrome ore from 0 to 4 mm, 20% flue dust and 4 % saturated kieserite solution, and the mixture was shaped into briquettes which at 1950 ° G in a Oven or shaft furnace were burned for about 3 hours.

The composition of the raw materials and the simultaneous sintering material were as follows:

Simultaneous sintering

0.91% 8.76% -

5.31 % 22.30 %

0.63 % 62.09%

0.00 %

0.69

3.40 g / cm ³

The sintered material was crushed and ground, and 67 % of this material with a grain size of 0.3 to 3 mm and 33% of a grain size of 0 to 0 * 12 mm became stones with the addition of 1% dry sulphite liquor and 1.5% water deformed that were fired at 1580 ° G and then have the following properties

Magnesite Chrome ore SiO ₂ 0.18% 1.72% Fe ₂ O ₅ 1.84% 15.96% Al ₂ O ₃ 0.11% 12.94% Gr ₂ O ₃ 0.00 % 55.54% GaO 0.45 % 0.19% MgO 45.87% 13.65 % Loss on ignition 51.55% + 0.23 % G / S Grain space weight

exhibited: sunk RG porosity 0098aV ~ MS94 KDF . DFB HBF at 1260 °

3, 18th G 4th g / cnr 17, 2 % 503 kp / cm > 1700 ° 0, % 98 kp / cm

BAO

Example 5: 72% magnesite a grain size between 0 and 0.12 mm were mm with 28% chrome ore from O to 4, ^20: mixed, o fly ash and 4% saturated Kieseritlösung, and the mixture was formed into briquettes at 2050 ° G were fired in a rotary or shaft furnace for about 3 hours.

The starting materials and the simultaneous sintering material had the following composition:

Simultaneous sintering

1, 08 Iv 8.30 : o

3.97 Ό 19.08>

1.71 , ο 65.45, c-0.41 -V 1.59 3.59 g / cm

From a mixture of 67% of the sintered material of one grain size from 0.3 to ο mm, 33 "# of the sintered material of one grain size from 0 to 0.12 mm, 1% dry sulphite waste liquor and 1.6 ■> .Yasser stones were formed and fired at 1570 ° G. These stones had the following properties:

Porosi did
KDF

DFB t _B

decreased HBF at 1260 ° G

Example 6: 72% magnesite a grain size between 0 and 0.12 mm by the process mentioned in Example 5 composition were coated with 28 / o chromium ore from 0 to 4 mm from the specified in Roispiel 4 Analysis, 20 \ i> flue dust and 4 o? saturated kieserite solution mixed, and the; Mixture was formed into briquettes that were used in

Magnesite Chrome ore SiO ₀ 0.15% 2.84- } o Fe ₂ O ₃ 2.40% 14.68 7o 2 3 0.45 % 9.63 vo Gr ₂ O ₅ 0.00% 54.50 Ίο CaO 1.15% 0.15 vo MgO 44.85% 16.55 : o Loss on ignition 51.00 % 1.65 &quot; ^ C / S Grain density

3.1 ^ς Ί ¹ g / cm 17, «i kp / cm '" 1700 ⁰ c 0.4 > 98 kp / cm '

009842/1694 ""> «« «« ■

2000 ° C were fired in a rotary or shaft furnace for about 3 hours.

The obtained sintered material was crushed and ground; 67 / o of this material with a grain size of 0.3 to 3 mm and 28 % of a grain size of 0 to 0.12 mm were mixed with 5% sintered magnesia powder of a grain size of 0 to 0.12 mm with the addition of 0.63 - ' ό 3oric acid, 0.5% dry sulphite waste liquor and 2.0% magnesium sulphate solution at 29 - 30 ° Be mixed and mixed to form stones. that have been dried at 180 ° G.

The composition of the sintered material and that added to it Siritermagnesia flour were as follows:

Simultaneous sintering Sinter mag 0.73 % 2.4 % 8.74% 3.8 # 4.14 % 0.6 % 16.65 % 0.0% 1.73 % 1.8 fo 68.01 fo 91.4% 2.37 3.40 g / cm ⁵

Corrugation space weight

The stones obtained had the following properties:

RG 3.08 g / cm ⁵

Porosity 11.8 fo

KDF

Interzone fixity (ZZF) after fire at 800 ° G ZZF after fire at 1000 ° G

KDF after tunnel furnace fire

DFB t

B dropped

HBF at 1260 ° G

654 kp / cm G % 225 0
kp / cm kp / cm 305 kp / cm 578 kp / cm " 1700 ° 0 103

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BAÖ

Claims (5)

Patent claims: . Process for the production of refractory magnesite chromium and chromium magnesite bricks, whereby chromium oxide-containing substances, in particular chromium ore, in a grain size of 0 to at most 6 m, preferably at most 4 ram, with finer-grain magnesite, optionally ointermagnesia, or other finer-grain, natural or synthetic, periclase when firing forming magnesium compounds with a grain size of less than 0.20 mm, preferably at most 0.12 mm, which, based on the fired .justani, contain less than 9Tu>, suitably less than 95>, itgQ, mixed and, preferably after deforming into briquettes or . Jteinen, sintered at temperatures of at least 17 ^Γ > 0 ° C, expediently at least 18S0 C, without melting and then this sintered material, which has a content of S to 40 <.>, In particular U ^ ve 20 to ^y ) 0 .o 'Jr ₀ O having, _t.'; ekornt and, optionally after addition of sintermarner.ia is deformed to stones, characterized daiurch that a) for the production of the Jint.or material at least 20 years, at most 80 / έ, the chromium oxide-containing substances have a grain size of less than 0.12 mm habon, b) the SLntf-M'mat ^ ri al a gravel is acid content of at most 2, b>, a Kalkgohalt of at most 4 % and c) a molar lime-silica ratio of over 0, o to 2, 'j. 2. The method according to claim 1, characterized in that (ins SinU> rmateri a! A gravel huiuregehal t of a maximum of 1, '>> ■ au f wo i r, t. 6. The method according to claim I o> ler. ', Characterized gekennzoiehnet that the chromox.ydhai term S to ff o have a grain size of 0 to at most 2 mm. 4. The method according to any one of claims 1 to -S _1, characterized in that the granular sintered material at most ^ '. <Sintered magnosia, based on the refractory mixture, are. , 0 BAO ORIGINAL 009842/1594 5. The method according to claim 4-, characterized in that your grained sintered material in the production of unfired stones using magnesium sulfate as a binder at most 8%, preferably 3 to 5 ° / ° t based on the refractory mixture, fine-grained Sintermagnesi.a one Grain size of 0.12 mm or less can be added. - 11 - 5.70 Dr L / a / _{# /} 008842/1694 BATH