Refractory concrete for cladding of silicium refining plunge and method for cladding production using the same

FIELD: non-iron metallurgy, in particular cladding of metal plunge.

SUBSTANCE: claimed refractory concrete contains (mass %): corundum mass 82-85; high-aluminous cement 4-5; electrical filter dust from silicium production 4-5; phosphoric acid 2-3; and water 3-4. Method for cladding manufacturing using the said concrete includes former installation into plunge; charging of refractory concrete into space between plunge internal wall and former, vibratory compaction, and two-step drying: at first at 20-250C for 5-7 days and then by graduated heating and drying. Namely, at first cladding is heated up to 1500C with rate of 6-80C/h and kept for 9-11 h; then cladding is heated up to 4000C with rate of 13-150C/h and kept for 14-16 h; then cladding is heated up to 6000C with rate of 20-220C/h and kept for 10-12 h. Cladding obtained by claimed method stands on silicium refining plunge up to 90 air thermal cycling.

EFFECT: cladding of improved strength.

2 cl, 4 tbl, 1 ex

 

The present invention relates to the field of nonferrous metallurgy and can be used for lining of steel ladles.

Known composition of the mixture for the manufacture of refractory products, including, wt.%: corundum 25-55, alumina 25-30, kaolinite-websiteby bauxite with silicon module 1,5-4,0 - 20-45% (A.S. USSR №1583392, SW 35/10, publ. 07.08.90).

Known mixture for the preparation of refractory materials (U.S. Pat. Of Ukraine No. 18397, 04 35/00, publ. 25.12.97), including, wt.%: corundum faction 3-00 16-38 mm, phosphoric acid 2-4, a mixture of a joint grinding particles less than 0.06 mm - 40-50 corundum, alumina, clay, mullite fused faction 3-0 mm - 20-30.

Known compounds unsuitable for lining ladles refining of silicon, because contain crystalline silica, contributing to the cracking of the lining.

Closest to the proposed (C. Of Ukraine No. 97041722, SW 37/22, Appl. 11.04.97) compound is a refractory ramming mass, comprising, by wt.%:

- electro-fused corundum - faction 3-1 mm and 1-0,5 mm in the ratio of 70:30 50-55

- alumina Ledger 32-37

quartz sand 4-6

- phosphoric acid 7-9

The disadvantage of this composition is its fragility when used as a lining for the ladle refining of silicon.

There is a method of lining metallurgical vessels (A.S. USSR №1724434, 22D 41/02, published the.07.04.92), including filing lining mass, seal pneumotropica, drying by heating, and vacuum simultaneously with the filing and sealing lining mass.

The disadvantage of this method is the impossibility of complete removal of gas voids using pneumatology, which reduces the strength of concrete.

The closest in technical essence is a method of lining metal containers (A.S. USSR №1072994, 22D 41/02, publ. 15.02.84), including the filing of the lining mass circular cycles, seal vibrations and drying using a burner with a built-in ultrasonic generator.

The disadvantage of this method is that with the help of the burner is achieved by a sharp rise in temperature. And because the humidity lining mass does not exclude the formation of lenses, filled with an aqueous solution, a sharp rise in temperature causes evaporation of aqueous solutions in the lens, i.e. create high pressure (several tens of atmospheres). The internal stresses formed in the lining due to the high pressure lead to the formation of microcracks.

Filling of cracks melt contributes to premature failure of the lining. This lining can withstand 7-10 air shifts.

Object of the present invention is to improve the reliability and durability of f is Teruki.

The technical result of the invention is to increase the plasticity of the lining (plastic deformation).

The technical result of the composition is achieved by the heat-resistant concrete for ladle refining of silicon, including corundum weight, aluminum-containing component, phosphoric acid, as the aluminum-containing component, it contains high-alumina cement, as the silica component it contains the electrostatic dust silicon and optionally water in the following ratio, wt.%:

- corundum mass fraction 0,0056-5.0 mm 82-85

- high-alumina cement 4-5

- electrostatic dust silicon 4-7

- phosphoric acid 2-3

- water 3-4

The technical result according to the method is achieved in that in the method of manufacturing a lining of ladle refining of silicon-based heat-resistant concrete, including the installation of a template in the bucket, the flow of heat-resistant concrete in the space between the inner wall of the bucket to the templates, compaction and drying, the drying is carried out in two stages: initially - in natural conditions at a temperature of 20-25°C for 5-7 days, and then stepped heating is first heated to a temperature of 150°at 5-7°/h and maintained at this temperature techenie-11 hours then heated to a temperature of 400°With speeds of 13-15°/h and kept at this temperature for 13-15 hours, then heated to a temperature of 600°with the speed of 20-22°/h and incubated for 10-12 hours.

The technical essence of the invention consists in the following:

It is known that phosphoric acid is chemically bonded and weakly basic compounds form strong ties. The process of curing of refractories due to chemical interaction of the components, which can be represented by the reaction:

or recrystallization:

Operational characteristics of the refractory lining largely depend on the velocities of its hardening, which in turn depends on the chemical interaction of the components and their structure formation.

In the prototype, the silica-containing component presents crystalline quartz sand, to which phosphoric acid is a strong chemical bonds are not formed.

The proposed structure provides for the use as a silica-containing component electrostatic dust silicon, which mainly consists of amorphous silica with a particle size of from 1 to 100 microns.

Table 1 shows the material is the composition of the dust.

Table 1.
 Mass fraction, %
ProductSi2OSiCCERFe2About3Al2About3CaONa2OMgO
dust e/f silicon production65-886-82-30,7-0,80,3-0,51,6-1,8of 0.2-0.30,5-0,6

Table 2 shows the material composition of the high-alumina cement, GOST 969-91, brand VHC-1

Table 2
Mass fraction, %
Al2About3CaOFe2About3Si3OMgOSO3Tio3
>60<32<1,0<3,0<1,5<2,0<0,05

With amorphous silica contained in the electrostatic dust silicon production, as with high-alumina cement, phosphoric acid enters into a chemical reaction. In the interaction the reactions of 1, 2 allocated water, reducing viscosity weight.

In addition, fine silica due to its small size particles can easily penetrate into the space between the larger filler particles and thus reduces the porosity and gives the plastic deformation of the lining when it is firing, and thus reduces the formation of cracks.

It should be borne in mind that when used in the composition of heat-resistant concrete high-alumina cement and electrostatic dust silicon production, it falls in the form of accompanying substances oxides of calcium, which affects the strength of concrete cured at temperatures above 25°C. the reason is that in the hydration process of concrete at temperatures above 25°along with dukellis hydroalumination, produce large quantities of tricalcium hydroalumination, which has a low adhesion with the rest mass of hardened concrete, which leads to a decrease in its strength.

The first stage of heating (150° (C) and exposure at the right temperature to remove the hygroscopic moisture.

At the second stage of heating (400° (C) and the corresponding extracts remove crystallization moisture.

The third stage of heating (600°C) and above is the basic decomposition of the phosphate with the formation of gaseous P2O5 that goes to shit.

Comparative analysis of the proposed structure with the prototype shows that the claimed composition of heat-resistant concrete used for lining of ladle refining of silicon, differs from the known composition of the fact that:

as the aluminum-containing component, it contains high-alumina cement;

as the silica component it contains the electrostatic dust silicon;

- additionally contains water;

- components are in the following ratio, wt.%:

- corundum mass fraction 0,0056-5,0 82-85

- high-alumina cement 4-5

- electrostatic dust silicon 4-7

- phosphoric acid 2-3

- water 3-4

Comparative analysis of the proposed method with the prototype shows that the inventive method of manufacturing the lining of the ladle refining of silicon-based heat-resistant concrete differs from the known fact that:

- drying of heat-resistant concrete is carried out in two stages: initially under natural conditions at a temperature of 20-25°C for 5-7 days, and then heating and drying produce speed: first heated to a temperature of 150°With speeds of 6-8°/h and kept at this temperature for 9-11 hours, then heated to a temperature of 400°With speeds of 13-15°/h and maintain the ri this temperature for 14-16 hours, then heated to a temperature of 600°with the speed of 20-22°/h and incubated for 10-12 hours.

Thus, the proposed technical solutions are different and correspond to the condition of patentability "novelty."

Analysis of the known technical solutions in this and related fields showed that the increase in plastic deformation of the refractory lining of the ladle refining of silicon in the prior art revealed no influence of the silica component in the form of dust electrostatic silicon containing amorphous silica and the composition of the lining, in which this component belongs to.

Technical solutions have signs consistent with signs of pre-drying in natural conditions at a temperature of 20-25°C for 5-7 days at a lining of steel ladles, not identified.

Thus, in the proposed solution a new set of features of both known and previously unknown from the prior art can improve the plastic deformation of the lining, to reduce cracking and thereby increase the amount of air thermal cycles, i.e. to obtain the specified technical result.

Hence, the proposed technical solution meets the condition of patentability "inventive step".

The possibility of implementation with the person is confirmed by the following example.

Example. For lining metallurgical ladle was used in lining the mass of the following composition, wt.%: corundum mass fractions of 5.0-0,056 mm - 82, high alumina cement brand VHC 1 - 5, the electrostatic dust silicon - 7, phosphoric acid - 3 water - 3.

Lining mass is prepared by thorough mixing in the mixer until the consistency of thick cream.

In the inner side surface of the bucket is placed insulating layer of a sheet of asbestos, then the bucket is placed the template.

Bucket mounted on a rotating stand, and after this lining serves the mass in the space between the inner wall of the bucket and the template to a height of 13-15 see

After passing the bucket full circular loop supply of 1thportions of the lining mass complete and proceed to seal the masses with the help of a vibrator, which lasts for 3-5 minutes

The feeding of the mass and its alternate seal up until the level of the compacted mass reaches the top level of the bucket. Then one day, after the formation of the cover concrete remove the template, and the bucket is left for drying in natural conditions at a temperature of 20°C for 7 days.

Then on the lid of the bucket fix the heater with a capacity of 40 kW, close the lid and carry out a first heating up to 150°With speeds of 6°C/h, uderjivayut at this temperature for 10 hours, then heated to a temperature of 400°With a speed of 14°/h and kept at this temperature for 15 h, then heated to a temperature of 600°With a speed of 20°/h and incubated for 11 hours.

Table 3 shows the composition of the lining of the prototype and proposed.

Table 3
№p/pThe composition of the lining, wt.%The number of air thermal cycles
1the prototype electro-fused corundum fraction 3-1 mm and fraction 1-0,5 ml in a ratio of 70:3 50

alumina GC 35

quartz sand 5

orthophosphoric acid 8
7
2Offer

corundum mass fractions of 5.0-0,056 mm 82

high-alumina cement brand VHC-1 5

dust e/f silicon production 7

orthophosphoric acid 3

water 3
90
3corundum mass fractions of 5.0-0,056 mm 85 high-alumina cement74
 brand VHC-1 4 dust

e/f silicon production 6

orthophosphoric acid 3

water 2
 
4corundum mass fractions of 5.0-0,056 mm 84

high-alumina cement brand VHC-1 5

dust e/f silicon production orthophos XG 5 is ornago acid 2

water 4
75
5corundum mass fractions of 5.0-0,056 mm 85

high-alumina cement brand VHC-1 4

dust e/f silicon production 4 orthophosphoric acid 3

water 4
83
6corundum mass fractions of 5.0-0,056 mm 83

high-alumina cement brand VHC-1 5

dust e/f silicon production 8 orthophosphoric acid 3

water 3
70
 corundum mass fractions of 5.0-0,056 mm 85

high-alumina cement brand VHC-1 5

dust e/f silicon production 3 orthophosphoric acid 3

water 4
63

As follows from table 3, the change of the upper limit on the mass fraction of dust electrostatic silicon leads to the shedding of the lining and the decline of air thermal cycles up to 70.

Reducing the lower limit of the mass fraction of dust electrostatic silicon leads to the formation of cracks in the lining and reduce air thermal cycles to 63.

Reducing the number of thermal cycles up to 70 is not economically viable for the production of silicon.

In table 4 show the results of running tests on the prototype and the proposed method.

As follows from tables 3, 4, compared with the prototype proposed in the m method quantity of air thermal cycles increased from 7-8 to 90.

1. Heat-resistant concrete for lining ladles refining of silicon, including corundum weight, aluminum-containing component, silica-containing component, phosphoric acid, characterized in that as the aluminum-containing component used high-alumina cement, as the silica component using electrostatic dust silicon and optionally contains water in the following ratio, wt.%:

corundum mass fractions of 5.0-0,056 mm 82-85

high-alumina cement 4-5

the electrostatic dust silicon 4-7

phosphoric acid 2-3

water 3-4

2. A method of manufacturing a lining of ladle refining of silicon-based heat-resistant concrete according to claim 1, including the installation of a template in the bucket, the flow of heat-resistant concrete in the space between the inner wall of the bucket and the template, compaction by vibration and drying, characterized in that the drying is carried out in two stages: initially under natural conditions at t=20-25°C for 5-7 days, and then heating and drying to produce a stepped - is first heated to a temperature of 150°With speeds of 6-8 deg/h and kept at this temperature for 9-11 hours, then heated to a temperature of 400°With speeds of 13-15 deg/h and kept at this temperature during the course the e 14-16 h, then heated to a temperature of 600°with the speed of 20-22 deg/h and incubated for 10-12 hours



 

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SUBSTANCE: claimed bulk contains (mass %) dicalcium silicate in form of nepheline sludge of grade > 0.3 mm - 47-62; and of grade < 0.3 mm - 22-35; and liquid glass (as calculated to alkaline silicate) 16-18. Present invention is useful in cladding of heat equipment, metal-smelting and metal-casting equipment, electrolyzes, in aluminum production, etc.

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1 ex, 1 tbl

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2 tbl

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2 cl, 1 tbl, 4 ex

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