Corundum hydraulically hardening mass

 

(57) Abstract:

Usage: as lining for thermal units roughing and nonferrous metallurgy, chemical industry, building materials industry, in particular for installations furnace steel processing. The mass contains, by weight. %: high-alumina cement 13-20, as such additives ilmenite concentrate from 0.7 to 3.0, and the rest of electrocorundum. table 2.

The invention relates to the production of refractories for thermal units in ferrous and nonferrous metallurgy, chemical industry, building materials industry, in particular for installations furnace steel processing.

In installations furnace steel processing unburned lining made of refractory mass is in contact with the molten metal and slag having a temperature often 1600oC. Therefore, the resistance in the service of unburned lining will be determined by qualitative indicators, it acquired during operation at a temperature of 1600oC.

Known corundum hydraulically hardening mass brand MKN-94, manufactured from oxide and alumina cement. This mass and the N-94 are the lower limit of the compressive strength (20 N/mm2) and high open porosity (32%) after firing at 1600oC /1/.

Known also similar mass:

MCT-1 on the basis of white electrocorundum, titanicthe electrocorundum and high-alumina cement,

MKTN-2 based on white fused corundum, high-alumina cement containing the additive of 1% titanium dioxide.

Refractories of these mass after firing at 1600oC also have a high open porosity: 30% MCT-1 and 28% MKT-2. The ultimate compressive strength of the refractories of these mass after firing at 1600oC is somewhat higher than in the case of mass MKN-94, and is 35 N/mm2.

Most are similar in composition (prototype) is a refractory material containing, by weight.

High-alumina cement 13-20

Titanium slag 0,8-3

Oxide Rest

Refractories of this mass after firing at 1600oC have a lower open porosity (22,5-23,2%) and a higher ultimate compressive strength (43,0 was 47.1 N/mm2) than the refractory mass MKN-94, MCT-1 and MCT-2 /2/.

With high open porosity refractory observed impregnation its molten metal and slag (having a temperature of mostly 1600oC), which leads to the m the refractories of the mass of the prototype after firing at 1600oC have a lower open porosity and higher strength in compression, the damaging effects of the above factors is reduced, but not sufficiently. Therefore, it is necessary to further reduce the open porosity and the increase in the compression strength after firing at 1600oC refractories made of hydraulically hardening mass corundum structure.

This Yale is achieved by use of a hydraulically hardening refractory mass, which includes such additives ilmenite concentrate in the following ratio, wt.

High-alumina cement 13-20

Ilmenite concentrate 0,7-3,0

Oxide Rest

Ilmenite concentrate has the following chemical composition, wt. TiO260,8, FeO 29,0, SiO23,7, Al2O32,4, MgO 0,3, Cr2O31,5, of 0.3 MnO, CaO 0,2, mGOK-2,4 (TU 48-4-267-73). Phase composition it is represented mainly by the mineral ilmenite FeTiO3unlike titanium slag, which is due to the smaller content of FeO predominant phase is rutile TiO2(chemical composition of titanium slag, m ptx2">

Ilmenite concentrate has a lower cost compared to titanium slag as titanium slag is a by product of processing of ilmenite concentrate. Found that the use of ilmenite concentrate as an additive in compositions with oxide and high-alumina cement leads to a sharp decrease of open porosity refractories (16-18%) and higher tensile strength in compression (23-47%) after firing at 1600oC compared with the same mass, including the quality of such additives titanium slag (prototype).

This unexpected phenomenon may be due to the fact that the ilmenite (FeTiO3in conjunction with impurities included in ilmenite concentrate (such as SiO2, MnO) has a more effective sintering activity than rutile (TiO2in conjunction with impurities (FeO, SiO2, MnO) that are part of titanium slag. The mentioned phenomenon requires a special investigation.

The addition of ilmenite concentrate in the amount of less than 0.7% has no significant positive effect, and the introduction of its more than 3% is impractical because it leads to a significant reduction of the temperature of the beginning of softening under NASA additives to reduce the open porosity and enhance the compressive strength is unknown.

Not found information about any use of a composition of the oxide, high-alumina cement and ilmenite concentrate.

Based on this, we believe that the proposed solution involves an inventive step.

Example. For the manufacture of the samples used:

oxide on THE 14-8-384-81 (mass fraction, Al2O398,8, Fe2O30,19, SiO20,61, Na2O+K2O 0,38);

high-alumina cement in THE 113-03-339-78 (mass fraction, Al2O374,86, CaO 21,54, SiO22,01);

ilmenite concentrate on THE 48-4-267-73 smaller 0,063 mm;

titanium slag on THE 48-10-31-78 smaller 0,063 mm

These materials were mixed in the ratios shown in table. 1, then the mixture was moistened with water in amount of 10% (over 100% of the dry mixture) and stirred until homogeneous. The wetted mass was stuffed in a split metal molds. After 24 hours the samples were removed from the forms and kept in a humid atmosphere. After 3 days of curing, the images were dried at 105-120oC and annealed in the furnace at 1600oC aged for 4 hours After roasting determined their indicators, which are listed in the table. 2. Samples for the determination of ultimate strength in compression and open porosity and - in the form of cylinders with a diameter of 36 mm, height 50 mm

Analysis of the data given in table. 1 and 2, shows that the use of ilmenite concentrate as such additives in corundum hydraulically hardening mass can reduce the open porosity of the samples up to 18.4-19,0% and increase their tensile strength in compression to 57.8-69,4 N/mm2after firing at 1600oC (compositions NN 1-3) compared with samples of composition # 4 (prototype) for which these indicators after firing at 1600oC, respectively 22,5% and 47.1 N/mm2.

Thus, compared with the prototype of the proposed mass allows to obtain materials with open porosity at 16-18% lower, and the limit of compressive strength on 23-47% higher.

Corundum hydraulic hardening mass, including aluminium oxide, high-alumina cement and titanium containing additive, characterized in that the quality of such additives it contains ilmenite concentrate in the following ratio, wt.

High-alumina cement 13 20

Ilmenite concentrate 0,7 3,0

Oxide, Ostalnoe

 

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7 cl, 2 tbl

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2 tbl

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2 cl, 4 tbl, 1 ex

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1 tbl, 4 ex

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2 tbl

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2 tbl

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3 cl, 1 dwg, 1 tbl

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1 tbl

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