SU1169960A1 - Refractory compound - Google Patents

Abstract

REFRACTORY MASS, including sintered granular magnesite, synthetic magnesium chromite and dispersive fused periclase, characterized in that, in order to increase mechanical strength and heat resistance of products, it will additionally contain a chromite concentrate of a fraction less than 1 mm with silica content not exceeding 3% in the following ratio components, May,%: Synthetic magnesium chromite 2-15 Dispersed fused periclase 5-30 (C Chromite concentrate (L fraction less than 1 mm with silica content not more than 3% 8-18 Sintegen granular nezistalny O5 (; o

Description

The invention relates to the refractory industry and can be used in the manufacture of periclase-chromite refractory products used for the lining of electric steel-smelting furnaces, copper-nickel converters and other thermal units.

The purpose of the invention is to increase the mechanical strength and thermal resistance of products, as well as to improve the quality of periclase-chromite refractories based on enriched and chemically pure refractory raw materials.

The introduction into the composition of the refractory of finely granular chrome concentrate fraction of less than 1 mm with a silica content of not more than 3% provides the product with high mechanical strength and heat resistance.

The size and structure of the chromite concentrate grains provides in the process of refractory preparation obtaining more dense raw products, which contributes to a better interaction of the VIS components during sintering. During brick firing, the interaction of small chromite grains with the surrounding mass due to a more intensive recrystallization process at the chromite periclase boundary leads to the appearance of numerous aggregate aggregates. Such aggregates-splices, consisting of chromite concentrate grains associated with -periclase crystals, are, as it were, additional elements of the granular skeleton, which have a more complex configuration than conventional grains.

The appearance of such elements additionally reinforces the structure and increases the mechanical strength of the refractory, as well as its thermal resistance. The increase in thermal stability is also promoted by a more uniform character of heat transfer due to an increased homogenization of the spinel phase in the product volume, which causes a decrease in local critical stresses in the brick structure.

When the chromite concentrate content in the refractory varies from the established limits, the strength and thermal resistance of the products are significantly reduced. Thus, by reducing the content of fine-grained chromite concentrate to less than 8%, the number of heterophase aggregates of chromospinelide – periclase growth decreases, thereby reducing strength and heat resistance; chromite and periclase occurring with an increase in volume.

With an increase in the upper limit of the granularity of the chromite concentrate more than 1 mm during sintering, there is a violation of the formation of bound aggregates-aggregates of the chromium perinelide periclase in the product due to the occurrence of diffusion porosity around the chromite grains. As a result of this, the mechanical strength and thermal resistance of the products is significantly reduced.

An increase in silica content in chronite concentrate of more than 3% during firing leads to the appearance of an excessive amount of the liquid phase, which prevents direct contact between fine-grained chromite and periclase and reduces the high-temperature strength of products, as well as promotes the assimilation of spinelide grains in the mass in turn, it homogenizes the structure and reduces the resistance to the advancement of thermal trash;

PRI me R. As raw materials, you used:

Sintered magnesite grades PMI-90 fraction 3-0 mm, ppm MgO -93%

Synthetic magnesium chromite, MD,%: MgO 19.1; Cg203 80.3; Alj03 the rest.

Dispersed melted periclase fraction less than 0.063 mm, ppm MgO 96.2%.

Chromite concentrate obtained by the Kempirs enrichment: Yo chromite ore, fractions 2-1 and 1-0 mm.

Khromitovskaya ore Kempirsaysk fractions of 1-0 mm.

For the manufacture of products, a mixture of the proposed components of a specific grain composition with a sulphite-yeast brew as a temporary binder was prepared and the products were pressed on a hydraulic press at a pressure of 150 MPa, dried and annealed in a tunnel kiln for 6 hours.) samples from the proposed mass and from the mass of the prototype. It follows from the table that periclase-chromium refractory materials of the proposed composition in terms of mechanical strength and thermal durability exceed well-known periclase-chromite products. 0 The advantages of the invention are the simplicity of its implementation under industrial conditions, which does not require capital expenditures, as well as the possibility of producing high-quality periclase-hromite products from enriched and chemically pure refractory raw materials. . The use of periclase-chromite refractories of the proposed composition will increase the resistance of the lining of the arches of electric furnaces by 20-30%.

gaeSintered granular magnesite 60

Synthetic chromite: magnesium 6

Dispersed fused periclase 2212

Chromite concentrate fraction 1-0 mm t2 (SiOg content 2.8%)

Sintered granularity

haemagnesitis 60

Synthetic magnesium chromite 2

Dispersed fused periclase 30

Chromite concentrate fraction 1-0 mm 8 (SiO content 2.5%)

LagaeSintered granular magnesite 62

Synthetic magnesium chromite 15

61

42

68

10.5

79

60

Dispersed fused periclase 5 Chromite concentrate fraction 1-0 mm 18 (SiO content., 3.0%) 12.5

Sintered magnesite 67

Synthetic magnesium chromite 8

. Dispersed fused periclase 17

Chromite concentrate fraction 1-0 mm 8 (SiOj content 2.8%)

gaeSpecheins granules magnesite 42 Synthetic magnesium chromite 10

Dispersed fused periclase 30

Chromite concentrate fraction 1-0 mm 18 (Si02 content 2.8%)

Sintered Granular Magnesite 60

Synthetic magnesium chromite 6

Dispersed fused periclae 22

Chromite concentrate fraction 2-1 mm 12 (SiO content - 3.0%)

Table continuation

52

38

76

11.9

48

69

 64

11.8

47

65

74

32

39

40

Sintered granular magnesite 60

7 Synthetic magnesium chromite 6

14

Dispersed fused periclase 22

Chromite ore fraction 1-0 mm 12 (SiOj content 3.8%)

Famous Sintered Granular

magnesite 65

Synthetic chromite

12.3 mn 17

Dispersed fused periclase 18

29

40

53

23

36

33

Claims (1)

FIRE-RESISTANT MASS, including sintered granular magnesite, synthetic magnesium chromite and dispersed fused periclase ', characterized in that, in order to increase mechanical strength and heat resistance of products, it additionally contains a chromite fraction concentrate of less than 1 mm with silica content of not more than 3% in the next the ratio of components, wt.%: Synthetic Magnesium Chromite Dispersed fused periclase Chromite concentrate fractions of less than 1 mm with a silica content of not more than 3% Sintered granular magnesite О> 1 1169960 2