RU2276120C2 - Method of production of the periclaselimeferruginous clinker - Google Patents

Abstract

FIELD: production of refractory bricks; methods of production of periclaselimeferruginous clinker.

SUBSTANCE: the invention is pertaining to the field of production of the refractory bricks, namely, to production of non-molded masses of the main composition used for manufacture and repairs of the hearths and banks of the open-hearth and arc steel furnaces. The technical result of the invention is the increased strength and the density of the lining produced by the method of ramming of the mass due to reduction of the open porosity and the increased temperature of the beginning of the deformation under the loading at the high temperatures. The method of production of the periclaselimeferruginous clinker includes the joint grounding of the raw components up to the specific surface area of the ready ground mixture particles equal to 0.2 - 0.5 m²/g , its briquetting with specific pressure of the molding ensuring the apparent density of the briquette of no less than 2.15 g/cm³, the burning of the briquette in the rotating furnace with production of the burnt briquette with the apparent density of no less than 3.15 g/cm³, crushing of the briquette and grading the crushed material into classes. The components of the raw materials mixture are taken in the following ratio (in mass %): magnesium-containing raw (in terms of MgO) - 62-89, calcium-containing raw (in terms of CaO) - 8-30, the ferrous-containing additive (in terms of Fe₂O₃) - 2.5-7.0.

EFFECT: the invention ensures the increased strength and density of the lining produced by the method of ramming of the mass due to reduction of the open porosity and the increased temperature of the beginning of the deformation under the loading at the high temperatures.

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Description

The invention relates to the production of refractories, namely unformed masses of the main composition used for the manufacture and repair of hearths and slopes of open-hearth furnaces and arc steel furnaces.

A known method of producing periclase-lime iron clinker, including wet grinding and mixing of raw materials, preparation of sludge containing oxides of magnesium, calcium, iron, and firing in a rotary kiln at a temperature of 1360-1450 ° C [RF Patent No. 2151535, C 21 C 5/36, op . November 20, 1999).

The disadvantage of this method of producing periclase-lime-iron clinker is that it has a low density and strength of grains, and therefore the desired fractional composition for subsequent mass production is not provided.

A known method of producing periclase-lime-iron clinker fraction of less than 8 mm, including oxides: MgO, CaO, SiO ₂ Al ₂ O ₃ and Fe ₂ O ₃ . The ratio of these oxides in the clinker is such that it allows one to obtain densely sintered powders and use them in the lining of open hearth furnaces. A method of obtaining a raw mix consists in grinding the raw components and firing them in a rotary kiln at a temperature of 1650 ° C [A.S. USSR No. 927782, C 04 V 35/04, op. 1980].

A disadvantage of the known composition and method is the inhomogeneity of the composition, as well as the high content of silica, which is one of the harmful impurity oxides, which forms a large number of silicate fusible compounds. All this leads to low durability of the hearth furnaces.

The closest analogue of the proposed method for producing periclase-lime-iron clinker is a method that includes grinding and mixing magnesium-containing, calcium-containing and iron-containing components, briquetting the mixture, burning briquettes in a rotary kiln to produce clinker with an apparent density of at least 3.15 g / cm ³ , crushing [grade ³ , g / cm ³ , US 2,447,412, publ. 08/17/48].

The disadvantage of this method is the insufficient strength of the obtained refractory due to poor sintering of magnesium hydroxide and the insufficient amount of calcium-containing and iron-containing components forming a ceramic bond, and also because of the heterogeneity of the structure of the initial mass and briquette, which, ultimately, leads to a decrease in the resistance of the refractory .

The objective of the invention is to increase the resistance of the hearths and slopes of steelmaking furnaces due to the creation of mainly refractory phases in the material used in the lining.

During the production of periclase-lime-iron clinker, the low-melting phase of ducalcium ferrite is specially synthesized in its composition. At the stage of creating a dense furnace lining (first smelting), it acts as a sintering agent; subsequently, due to the reducing properties of the metal bath, dicalcium ferrite is reduced to calcium oxides and iron oxides, the latter interacting with magnesium oxide to form refractory compounds - wustites and magnesium ferrites .

The technical result of the invention is to increase the strength of the lining made by tamping the mass, reduce open porosity, increase the temperature of the onset of deformation under load due to the solidity of its composition, well sintering in metallurgical units, provided with the chemical and phase composition of the clinker and rational grain composition of the masses.

The specified technical result is achieved due to the fact that in the method for producing periclase-lime-iron clinker, including grinding and mixing of raw materials: magnesium-containing, calcium-containing and iron-containing additive, briquetting the mixture, firing briquettes in a rotary kiln with obtaining clinker with an apparent density of not less than 3 g of density not less than 5 g of not less than 5 cm ³ , crushing and classification, the initial raw materials are taken in the following ratios wt. share,%:

- magnesium-containing raw materials (in terms of MgO) - 62-89

- calcium-containing raw materials (in terms of CaO) - 8-30

- iron-containing additive (in terms of Fe ₂ O ₃ ) - 2.5-7.0,

crush and mix the components by co-grinding to a specific surface area of 0.2-0.5 m ² / gram, briquetting with a specific pressing pressure that provides an apparent briquette density of at least 2.15 g / cm ³ , classification is carried out into classes: 8-5 mm, 5-3 mm, 3-1 mm and 1-0 mm.

Natural and / or calcined magnesite is used as a magnesium-containing raw material, dolomite and / or calcite is used as a calcium-containing raw material component, rolled iron oxide or an agglomeration product of iron ore is used as an iron-containing additive.

As an example, confirming the possibility of implementing the proposed method, we consider the preparation of periclase-lime iron clinker.

The following materials were used as feedstock for the production of periclase-lime-iron clinker:

- natural magnesite,

- calcined magnesite,

- dolomite

- calcite,

- iron oxide.

The chemical composition of these materials is shown in table 1. The composition of the charges for clinker are presented in table 2.

The coarse-grained feedstock was crushed to a fraction of less than 1 mm, in accordance with the composition of the charge was loaded into a mill, crushed to a specific surface area of 0.2-0.5 m ² / g. The grinding product was briquetted to a briquette density of at least 2.0 g / cm ³ . The briquette was fired in an oven to an apparent density of at least 3.15 g / cm ³ . The chilled clinker was crushed and classified into fractions of 8-5 mm, 5-3 mm, 3-1 mm and 1-0 mm. To prepare the finely ground component mass, a part of the clinker fraction less than 1 mm and periclase powder of the same fraction were used. The chemical composition and properties of clinker are shown in table 3, the chemical composition of finely ground periclase in table 4

Weights were prepared in accordance with the proposed formulation in mixing runners with or without a binder. The sequence of feeding the components of the mixture into the mixer and the mixing cycle is traditional. The compositions of the masses are shown in table 5 and the properties of the refractories made on their basis in table 6.

Table 6
Refractory Properties Name of indicator Sample Numbers one 2 3 four 5 prototype The density of the rammed mass, g / cm ³ 2.78 2.72 2.75 2.77 2.40 The compressive strength after firing at 1600 ° C, kN / mm ² 41.6 43.1 45.0 51.7 26.0 The apparent density, g / cm ³ 3.15 3.21 3.23 3.25 2.92 Open porosity,% 20,4 22.5 21.8 18.6 25,2 Additional shrinkage,% 0.3 0.2 0.2 0.2 0.6 Deformation onset temperature, ° С 1690 > 1710 1700 1700 1580 Heat resistance (1300 ° С-water), heat exchange 3 3 3 3-4 2

Claims (1)

A method for producing periclase-lime-iron clinker, including grinding and mixing of raw materials: magnesium-containing, calcium-containing and iron-containing additives, briquetting the charge, burning briquettes in a rotary kiln to produce clinker with an apparent density of at least 3.15 g / cm ³ , differentiation and crushing that the initial raw materials are taken in the following ratio, parts by weight %: magnesium-containing raw materials (in terms of MgO) - 62-89, calcium-containing raw materials (in terms of CaO) - 8-30, iron-containing additive (in terms of Fe ₂ O ₃ ) - 2.5-7.0, grinding and mixing the components by co-grinding to a specific surface area of 0.2-0.5 m ² / g, briquetting with a specific pressing pressure that provides an apparent briquette density of at least 2.15 g / cm ³ .