RU2749446C1 - Charge and method of obtaining flux and refractory material for steel production (options) with its use - Google Patents

Abstract

FIELD: metallurgy.SUBSTANCE: invention relates to the field of metallurgy and can be used to obtain refractory lime-magnesia-ferruginous agglomerate. The charge contains scrap of used periclase-carbon refractories of the fraction of 0.1-20.0 mm as a material containing calcium oxide, a material containing at least 80 wt% of CaO, fractions of 0.1-1.0 mm and as a material containing iron oxide - a material containing at least 80 wt% of Fe2O3, fractions of 0.1-1.5 mm, with the following content of components, wt%: material containing calcium oxide, 5-20, material containing iron oxide , 3-6, coke of fraction 0.1-3 mm 3-5, scrap of spent periclase-carbon refractories - the rest. Scrap of spent periclase-carbon refractories before mixing is subjected to crushing, screening, air-gravity classification with the release of products of fractional composition of 0.4-20.0 mm and 0.1-4.0 mm and a separate two-layer stacking of the separated fractions of scrap is carried out on the sintering surface of the grate in lower and upper layers of the charge, agglomeration is carried out in an oxidizing environment at a temperature of 1250-1500 °C for 15-25 minutes until the residual carbon content is less than 0.1 wt%.EFFECT: resulting refractory lime-magnesia-ferrous agglomerate can be used as high-magnesia fluxes for steelmaking and as a refractory material for the manufacture and repair of hearths and slopes of electric arc furnaces.9 cl, 6 tbl

Description

The invention relates to ferrous metallurgy and can be used for the production of refractory materials and fluxes for steel-making units.

Known charge for the production of steel-making flux, including a material containing iron oxides and silica, dolomite and hydrated waste of firing dolomite in the following ratio of components, wt.%: Dolomite 20-70; hydrated dolomite roasting waste 20-70; material containing iron oxides and silica - the rest (RU 2207382, С21С 5/36 dated 17.04.2002)

The main disadvantage of this charge is the high content of carbon dioxide in dolomite CaMg (CO ₃ ) ₂ and water in hydrated waste from the firing of dolomite Ca (OH) ₂ + Mg (OH) ₂ , which necessitates high consumption of thermal energy for decarbonization of dolomite and hydration of its waste.

In addition, the high content of low-melting components in the form of a combination of calcium and iron oxides, as well as silica, sharply reduces the refractoriness of the products of firing the charge in a rotary kiln. In addition, this charge causes intense ring formation in the high-temperature zone of the rotary kiln.

There is also known a method of obtaining ferruginous magnesia flux, where natural magnesite, calcined magnesite in the form of caustic magnesite of fraction less than 0.2 mm and siderite ore are used as the initial raw material charge, which are fed directly into the furnace, with the following component ratios, wt%: natural magnesite 40-45; caustic magnesite 20-55; siderite ore 5-15; (RU 2296800, С21С 5/36 dated 01.04.2005).

The disadvantage of this charge is the need for high-temperature firing (1550-1700 ° C). The composition of the charge is dominated by carbonate minerals:

natural magnesite MgCO ₃ and siderite ore FeCO ₃ , containing up to 48% and up to 38% carbon dioxide, respectively. The total amount of these carbonate components is 45-60 wt.%. Thermal decomposition (decarbonization) of magnesite and siderite requires significant, additional large expenditures of thermal energy.

Close in material (chemical and mineral) composition is a charge comprising a mixture of dolomite, caustic magnesite and (or) calcined magnesite and iron-containing material, with the following ratios of components, wt.%: Dolomite 45, -65.0; caustic magnesite and or calcined magnesite 25.0-50.0; iron-containing material 5.0-10.0. Moreover, dolomite has a grain size of 5.0-15.0 mm (RU 2381279, С21С 5/36, April 14, 2008). The charge has a calcareous-magnesian-ferruginous composition. In the known charge, caustic magnesite and (or) calcined magnesite are used as a magnesium-containing feedstock, the mineral base of which is a nanoscale mineral - periclase MgO. The technical name of the material is nanopericlase.

The MgO content in these magnesian components is not less than 90 wt%. As the initial iron-containing material in the charge, iron oxides are used in the form of siderite (FeCO ₃ ), siderite agglomerate (FeO, Fe ₃ O ₄ , Fe ₂ O ₃ , MgFe ₂ O ₄ ), as well as iron-containing wastes that are formed at metallurgical enterprises, for example , aspiration dust from steelmaking. The optimum firing (thermogranulation) temperature in a rotary kiln is between 1500-1680 ° C.

The disadvantage of this charge is a rather high content of valuable and scarce magnesia products, up to 50 wt%, represented by caustic and (or) calcined magnesite. These materials, consisting of MgO (more than 90 wt.%), Are relatively expensive and scarce; they are multifunctional mineral raw materials for other valuable types of products in a number of industries. The use of these materials in the amount of 25-50% in the charge for the steelmaking flux, therefore, is technically and economically inexpedient. The high purity of nanopericlase does not allow sintering the charge at temperatures below 1500 ° C. High temperature sintering of a known charge, the presence of carbonate components in it - dolomite CaMg (CO ₃ ) ₂ and siderite FeCO ₃ lead to additional fuel consumption during sintering of the mixture.

The closest in material composition to the claimed one is a charge consisting of a mixture of natural magnesite and calcined magnesite in mass ratios (30: 70-70: 30) with the addition of carbon in the form of coke in an amount of 5-15% of its total weight (RU 2244017, С21С 5/36 01/22/2002). The charge is a finely dispersed mixture of particles with a specific surface area of 0.6-1.2 m2 / g (average particle size of 1.5-3.0 microns), which requires high energy consumption and time for its very fine grinding. In terms of material composition, this charge is a mixture of carbonate MgCO ₃ (magnesite), periclase MgO (calcined magnesite) and carbon. At the same time, a significant content of natural MgCO ₃ in it (30-70% wt.), When used as a modifier (flux) in a steel-making unit, leads to cooling of the metallurgical melt, and also causes intense dust formation due to instant (explosive) thermal decomposition with the release of carbon dioxide MgCO3 -> MgO + CO2 and large loss of raw materials due to dust entrainment. The initial charge has a calcareous-magnesian-ferrous material composition, it contains, wt%: CaO 0.5-10.0; Fe2O ₃ 0.5-6.0; SiO ₂ 0.5-5.0; C (carbon (coke)) 5.0-15.0; MgO balance (62.75-93.07); Δm prc 0.43-4.25.

A known method for the production of a highly basic agglomerate, including mixing the components of the charge, their moistening, grinding to a particle size of less than 0.1 mm, pelletizing and sintering in a rotary kiln at 1320-1500 ° C for 15-20 minutes.

The method allows you to obtain a highly basic agglomerate with a ratio (CaO + MgO) / SiO ₂ > 7 (RU 2175987, 15.05.2000)

The main disadvantage of this method is the need for fine grinding of all components of the charge with high specific energy consumption. In addition, the roasting of a finely ground charge in a rotary kiln is accompanied by a significant carryover (up to 30%) of the weight of the charge materials, which significantly increases the cost of sinter production.

There is also known a method for the production of highly acidic agglomerate, including mixing, pelletizing and two-layer stacking of the charge on the sintering trolley of the sinter machine with different content of components in the upper and lower layers (AS No. 1574656, C22B 1/16, 02.02.1988). The method is used for agglomeration of iron ore raw materials with a high content (60-90 wt.%) Of low-melting iron oxide FeO, having a melting point of 1370 ° C. The use of this method is limited to agglomeration of relatively low-melting oxide-iron-containing materials. For agglomeration sintering of a more refractory inventive lime-magnesian-ferrous charge, the known method is not effective, since it requires an increased (more than 10 wt.% Of the total charge weight) introduction of coke. Even with a fuel consumption (coke) in the charge of 5-7 wt.%, The agglomerate of the claimed composition obtained by this method has an open porosity of more than 35%.

The closest in technical essence and the achieved result is a method for the production of a flushing agglomerate, including introducing into the charge a mixture of iron-containing materials with dolomite CaMg (CO ₃ ) ₂ , dolomitized limestone CaMg (CO ₃ ) ₂ + CaCO ₃ , limestone CaCO ₃ and (or) lime CaO as MgO / CaO≥0.2 with basicity CaO / SiO ₂ ≤0.7, and loading the charge with two layers of different material composition (AS No. 2158316, С22В 1/1, 31.12.1999).

To implement this method, 25-30% of the total charge with wt. The share of fuel in it is 2.0-2.7%, and the share of fuel in the charge of the upper layer is 5.8-6.4% of the mass of the upper layer, while in the resulting agglomerate the total iron content is more than 60%, and the FeO content is not less twenty%.

The disadvantage of this method is also limited use for heat treatment of relatively low-melting materials and charges with an iron content of more than 63 wt.%. Such materials and mixtures based on them have a temperature of complete melting (to a fluid state) no more than 1500-1550 ° C. The charge is fired according to this method in a reducing environment at a temperature not exceeding 1400 ° C. It is difficult to obtain a sufficiently dense and durable agglomerate of universal application from the claimed calcareous-magnesian-ferruginous mixture by this method, since it is required to introduce into it additionally up to 5-7% wt. coke.

The objective of the claimed technical solution is to obtain a sintered universal lime-magnesia-ferrous product, a refractory agglomerate of dual use: as a steel-making flux and an unshaped refractory material for the hearths and slopes of electric furnaces based on mostly cheap man-made magnesian raw materials with a minimum cost. In the cost of production of fluxes and refractory materials, the cost of raw materials usually ranges from 20-65%. The main direction of reducing the cost of production of fluxes and refractories is the replacement of expensive natural and especially artificial mineral raw materials (for example, nanopericlase) in the charge with a much cheaper technogenic one, that is, optimization of the material composition of the charge to reduce the cost of its processing.

To achieve this task, it is advisable to use cheap man-made mineral raw materials, as well as the most economical and simple way of processing them. In this regard, scrap of spent periclase-carbon refractories, lime and iron-containing production wastes were selected as raw materials. For efficient recycling in steelmaking, oxidative decarburization of scrap and pelletizing of roasting products together with sintering additives are required. At the same time, cost reduction is ensured by the presence of up to 12% of its own carbon (graphite, coke) in the scrap itself, in this case the introduction of additional fuel into the charge will be minimal.

The complete burnout of graphite and coke occurs in the temperature range 600-1000 ° C, while a loose, porous periclase material with low mechanical strength is formed. For recycling in steelmaking, decarburized periclase scrap must be subjected to high-temperature sintering (temperature range 1250-1500 ° C). The maximum reduction in the duration of oxidative heat treatment and sintering of scrap is achieved by introducing sintering additives in the form of oxides of iron, calcium, aluminum and silicon into the charge. At the same time, it is technically and economically most expedient to combine decarburization and sintering by the sintering method.

A preliminary experimental study established the main parameters of decarburization and agglomeration of a lime-magnesian-ferrous mixture, determined the mineral, chemical composition and physicochemical properties of the products of high-temperature sintering in an oxidizing environment.

The main minerals of burnt scrap in the presence of mineralizers (sintering additives) are periclase MgO and calcium ferrites; represented by a solid solution (Ca ₂ Fe ₂ O ₅ + Ca ₂ AlFeO ₄ ), and silicates: Ca ₃ SiO ₅ and β-Ca ₂ SiO ₄ with melting temperatures of 2070 ° C and 2130 ° C, respectively.

Dicalcium ferrite 2CaO⋅Fe ₂ O ₃ and brownmillerite Ca ₂ AlFeO ₄ (4CaO⋅Al ₂ O ₃ ⋅Fe ₂ O ₃ ) are relatively less melting compounds with a melting temperature of 1436 ° C and 1415 ° C, respectively, they perform the function together with silicates sintering additives for periclase. Their total number determines the temperature and duration of agglomeration.

For agglomerative sintering of the flux, depending on its composition, a temperature of 1250-1350 ° C and a duration of oxidative firing for 15-20 minutes are required. With a decrease in the lower values of these thermal-time parameters, the resulting flux has high porosity and low mechanical strength.

An increase in the maximum temperature of the oxidative heat treatment (1350 ° C) causes excessive fuel consumption without a noticeable improvement in the quality of the sinter.

To obtain a refractory agglomerate, agglomeration is carried out at a temperature of 1350-1500 ° C for 20-25 minutes in an oxidizing environment. At temperatures below 1350 ° C and holding for less than 20 minutes, carbon burnout of less than 0.1 wt% is not ensured and a sufficiently dense and strong agglomerate structure is not formed. More intense high-temperature firing (T> 1500 ° C) with longer sintering is unreasonable, since the thermomechanical properties of the refractory agglomerate do not improve, but causes additional fuel consumption in the charge.

The task is achieved by the fact that the known calcareous-magnesia-ferruginous charge for the production of a slag modifier (flux), containing components with oxides of magnesium, calcium, iron and carbon-containing material, according to the invention additionally contains scrap of spent perlase-carbon refractories in the following qualitative and quantitative ratios of components, wt%:

carbon-containing material fraction 0.1-3.0 mm 3-5 material of fraction 0.1-1.0 mm containing at least 80 wt% CaO 5-20 material of fraction 0.1-1.5 mm, containing at least 80 mass. % Fe ₂ O ₃ 3-6 scrap of spent periclase-carbon refractories fraction 0.1-20 mm rest

It is advisable to use coke with an ash content of not more than 15 wt.% As a carbon-containing material; as a material containing calcium oxide, use ground lime and (or) lime dust of roasting units; as a material containing iron oxide, use ground mill scale and (or) dust and sludge of steelmaking and (or) blast furnace production. At the same time, all components are included in the composition of the charge in a dust-free form, dispersed particles in materials less than 100 microns (0.1 mm) are absent in them.

According to the proposed technical solution, obtaining a refractory lime-magnesia-ferruginous agglomerate is carried out by performing technological operations in the following sequence.

Scrap of periclase-carbon products is subjected to crushing, screening, air-gravity classification with the release of a product with a fractional composition of 0.1-20.0 mm. In this case, the fraction 0.1-20.0 mm of this product is divided into two parts: 0.1-4.0 mm and 4.0-20.0 mm. The coarse-grained component of the scrap is placed in the bottom layer (bed) of the sinter plant in an optimal amount depending on the refractoriness and the intended purpose of the resulting agglomerate. The upper layer is a mixture of a fine-grained part of scrap (fractions 0.1-4.0 mm) with the rest of the components of a part of the charge enriched with fluxing oxides in the form of a mixture of CaO lime, iron oxides FeO, Fe2O3; Fe3O4, Al2O3 and SiO2.

To obtain a calcareous-magnesian-ferruginous flux (slag modifier), 57-73 wt.% Of coarse-grained scrap (fractions 0.4-20 mm) is loaded into the bottom layer, and a mixture of the remaining components of the charge with fine-grained scrap (fractions 0.1 -4 mm) with the following ratio of components, wt%:

scrap fraction 0.1-4.0 mm 10-20 calcium oxide material 8-20 iron oxide material 5-6 coke 4-5

The thickness of the lower layer is 23-25 cm. This charge is agglomerated in an oxidizing environment at a temperature of 1250-1350 ° C to a residual carbon content of not more than 0.1 wt.%.

To obtain a refractory agglomerate of a calcareous-magnesian-ferrous composition, 60-70 wt.% Of coarse-grained scrap (fraction 4.0-20.0 mm) is loaded into the bottom layer, and a mixture of fine-grained scrap (fractions 0.1-4, 0 mm) with the rest of the charge components at the following component ratios, wt%:

scrap fraction 0.1-4.0 mm 19-24 calcium oxide material 5-8 iron oxide material 3-4 coke 3-4

The thickness of the upper layer of the mine is also 23-25 cm. The upper layer is laid on the lower one with a thickness of 23-25 cm. This mine is agglomerated in an oxidizing environment at a temperature of 1350-1500 ° C to a residual carbon content of no more than 0.1 wt%.

The declared limits of the contents of the charge components are determined by the chemical (table 1) and mineral (table 2) composition of the raw materials.

The material (chemical and mineralogical) composition of the initial (raw) materials shown in Tables 1 and 2 shows that the main scrap minerals of spent periclase-carbon refractories are periclase and graphite (up to 93 wt% in total). The mineral base of materials containing calcium oxide is represented by free lime CaO and partly by its hydrate (portlandite) Ca (OH) ₂ .

Lime in combination with an iron-containing material has a low melt appearance temperature (~ 1205 ° C) and plays the role of a sintering additive in the charge during its agglomeration. When the content of the lime-containing component is more than 20 wt%, free lime appears in the agglomerate, not bound in ferrites, silicates and aluminates. The presence of free lime causes lime decomposition of the agglomerate as a result of hydration of lime with water vapor according to the reaction: CaO + H ₂ O -> Ca (OH) ₂ with an increase in volume by almost 2 times. When the amount of CaO-containing material is less than 8.0 wt.% And the iron-containing component is less than 3.0%, the resulting agglomerate has high porosity and low mechanical strength. The amount of the iron-containing component is more than 6.0 wt.%, The refractoriness of the agglomerate is sharply reduced.

For the specific implementation of the claimed objects of the technical solution, an experimental sinter plant with a grate and an air suction system during agglomeration was used. For experimental firing in an agglomeration plant, eight experimental mixtures were prepared for 4 two-layer charges (examples 1-4 in table 3) and one single-layer charge - a prototype (example 5 in table 3).

The charge was placed on a grate in two layers, each 23-25 cm thick. In examples 1, 2, 3 and 4, scrap of spent periclase-carbon refractories of fraction 0.4-20.0 mm was loaded into the lower layer in an amount of 57, 73, 60 and 70 wt%, respectively (table 3).

The upper layer of the charge contained a mixture of four components:

scrap of the specified refractories in an amount from 10 to 24 wt.%;

a material containing calcium oxide in the form of quicklime (5-20 wt%);

milled mill scale (3.0-6.0 wt.%);

coke (3.0-5.0 wt.%).

The chemical composition of all components of the charge is shown in Table 1. The charge was ignited using shavings moistened with kerosene. The temperatures at the boundary of the charge layers at a depth of 24 cm were measured with a platinum-rhodium (Pt-Rh) thermocouple. Sintering in all stages was carried out in an oxidizing environment (excess air for combustion more than 1.4). To obtain a flux agglomerate (see examples 1, 2 in table 3), the maximum amount of fluxing components (a combination of CaO and Fe ₂ O ₃ ) was introduced into the upper layer in a mixture with coke and various scrap content of spent periclase-carbon refractories of fraction 0.1-4, 0 mm. Agglomeration sintering was performed in all examples in an oxidizing environment at a temperature of 1320 ° C for 15 minutes (example 1) and at 1350 ° C for 15 minutes (example 2) until the residual carbon content in the resulting agglomerate was not more than 0.1 wt% ... It was experimentally found that the sintering temperature is less than 1250 ° C and the duration of heat treatment is less than 15 minutes does not allow reducing the content of residual carbon in the finished agglomerate less than 0.1 wt.%. More high-temperature and longer sinter firing practically does not change the quality of the target product, but leads to a change in fuel consumption (coke).

To obtain a refractory agglomerate (examples 3 and 4 in table 3), the minimum total amount of fluxing components (CaO-containing in combination with Fe ₂ O3-containing) and coke was introduced into the upper layer with the maximum total content of scrap of both fractions in a two-layer (total) charge (in examples 3 and 4, respectively, 84 wt.% and 89 wt.%) (table 3). Agglomeration was also carried out in an oxidizing environment at a temperature of 1400 ° C and 1500 ° C for 25 minutes and 20 minutes until the amount of residual carbon was reduced to less than 0.1 wt% (example 3, 4 table 3).

For agglomeration sintering of the charge according to the prototype (RU 2244017), a mixture of natural magnesian raw materials was used: magnesite MgCO _{3 from the} Satkinsky deposit and brucite Mg (OH) _{2 from the} Kuldursky deposit in a mass ratio,%: 30:60. As fuel, 10 wt% carbon was introduced into the charge in the form of a coke (the chemical composition of the coke is shown in Table 1). Agglomeration of the prototype charge was performed in an oxidizing environment at a temperature of 1500 ° C for 20 minutes until the residual carbon content in the resulting agglomerate was less than 0.1 wt% (example 5, table 3).

For all the obtained agglomerates, the chemical, mineralogical composition (tables 4, 5) and the main physicochemical properties were determined: refractoriness, temperature onset of deformation under load, open porosity, solubility in the slag melt and slag resistance (table 6).

Refractoriness was determined from finely ground agglomerate powders in accordance with the requirements of GOST 4069-69. To determine the temperature of the onset of deformation (so-called deformation) under load in accordance with GOST 4070-83, pressed samples were made from poly-mixtures of the fraction (grain size 3-0 mm) of each agglomerate. The determination of high-temperature properties was carried out in an oxidizing environment. To determine the open porosity in accordance with GOST 2409-95, the agglomerates were subjected to crushing to obtain a monofraction of 10-6 mm. The results of determining the listed properties of agglomerates are shown in Table 6.

For the agglomeration of the charge - the prototype, the stacking of a mixture of natural raw materials, represented by magnesite and brucite, was done in one layer.

Solubility in the slag melt was determined by a non-standard method using converter slag of OJSC "NTMK" containing, wt%: CaO 29.5; SiO ₂ 14.3; FeO 25.2; MgO 6.40; MnO 4.41; Al ₂ O ₃ 4.36; V ₂ O ₅ 3.9; CaO / SiO ₂ 2.6. The slag was preliminarily crushed to a fraction of 1.0-0 mm, loaded into a zirconia crucible and heated to complete melting at a temperature of 1620 ° C, samples of agglomerates pressed from polyfunctional mixtures were immersed in the molten slag and kept in it for 30 minutes. The calculation of the solubility R is made according to the formula

R = (C2-C1) ⋅100 / C1,%,

where C1 is the concentration of MgO in the slag before testing, wt%:

C2 - also after tests, wt%.

The results of determining the solubility in the slag are shown in Table 6. The assessment of the solubility was made by the corrosion area in the vertical axial section of the crucibles after testing.

Analysis of the data given in table 6 allows us to draw the following conclusions about the quality of the calcareous-magnesian-ferruginous agglomerates obtained by the claimed method:

- the resulting agglomerates have a low production cost;

- all agglomerates are refractory material (refractoriness over 1580 ° C);

- all agglomerates can be used in two ways: as high-magnesia fluxes for steelmaking for modifying the slag melt and in the form of refractory, easily sintered, unshaped refractories (polyfractional powders) for the manufacture and repair of the hearth of electric arc furnaces;

- agglomerates with lower values of refractoriness and temperature, the beginning of deformation under load (compositions 1 and 2 in Table 6) are more preferable for use as high-magnesian fluxes (monograph by K.N.Demidov, T.V. Borisov, A.P. Vozchikov " High magnesium fluxes for steelmaking "- Yekaterinburg. - Ural worker. - 2013. - 280 p.);

- agglomerates with a high MgO content (compositions 3 and 4 in Table 6) are quite suitable for lining the bottom of steel-making units (monograph by I. D. Kashcheev, I. P. Bas'yas, G. A. Farafonov, V. I. Sizov) "Lining arc steel-making furnaces ”. - M: - Intermet engineering. - 2010 - 192 p.).

Information sources

1. RU 2207382, С21С 5/36, 17.04.2002

2. RU 2296800, С21С 5/36, 01.04.2005

3. RU 2244017, С21С 5/36, January 22, 2002

4. RU 2381279, С21С 5/36. April 14, 2008

5. RU 2175987, May 15, 2000

6.A.S. No. 1574656, С22В 1/16, 02.02.1988

7.A.S. No. 2158316, С22В 1/1, 31.12.1999)

Table 1.

Material MgO Al ₂ O ₃ SiO ₂ Fe ₂ O ₃ Δm prc CaO Other Scrap of periclase-carbon refractories 80.0 3.0 3.5 1.6 10.1 * 2.0 0.3 Lime material 4.0 0.8 3.1 0.5 3.9 ** 87.6 - Ferrous material 4.1 2.7 7.5 74.9 1.2 * 5.8 3.7 Carbonaceous material (coke) 0.3 2.9 6.8 3.5 85.0 * 0,4 0.9

* Weight loss is related to carbon content

** Weight loss is due to the presence of Ca [OH] ₂ .

Table 2.

Name (melting point ° C) Chemical formula Scrap of PU-refractories Lime-containing materials Ferrous materials Koksik Periclase (2800) MgO 80-85 3-5 1-3 ----------- Carbon (graphite, coke, etc.) (> 4300) FROM 10-13 --------------- 1.0-2.0 ----------- Spinel (2135) MgAl ₂ O ₄ 3-4 -------------- <0.5 ----------- Lime (26250) CaO ------------- 85-88 1-2 ----------- Portlandite Ca (OH) ₂ ------------- 12-15 1-3 ---------- Wustite (1370) magnetite (1580) FeO, Fe ₃ O ₄ Fe ₂ O3 0.5-1.9 ------------ 75-80 ---------- Silicates + glass R ₂ O⋅RO · Al ₂ O ₃ ⋅SiO ₂ 1.0-1.8 0.5-1.0 8-10 Ash 15-20 Iron (Fe) (1536) Fe 1.0-1.5 ---------- 2-3 -----------

Table 3.

Charge layer Components Execution example 1 Execution example 2 Execution example 3 Execution example 4 Prototype Pat. 2244017 Runtime example 5 * Material containing CaO, wt% 20.0 8.0 8.0 5.0 ----------- * Material containing Fe ₂ O ₃ , wt% 6.0 5.0 4.0 3.0 ------------ * Material containing carbon, wt% 5.0 4.0 4.0 3.0 10.0 * Scrap of periclase-carbon refractories, fr. 0.1-4.0 mm wt.% 12.0 10.0 24.0 19.0 ----------- ** Scrap of periclase-carbon refractories, fr. 0,4-20,0 mm 57.0 73.0 60.0 70.0 ----------- The total amount of scrap in the charge, wt% 69.0 83.0 84.0 89.0 ---------- Natural magnesite of the Satka deposit, wt% MgO ~ 95 wt% ---------- ---------- ---------- ---------- 30.0 Natural brucite of the Kuldur deposit, wt% Mg (OH) ₂ ~ 90 wt% ---------- ---------- ---------- ---------- 60.0

The example columns indicate the content of the components in each layer. wt%.

* Top layer of the charge.

** Bottom layer of the charge.

Table 4.

No. No. of example of execution MgO CaO Fe ₂ O ₃ Al ₂ O ₃ SiO ₂ C, wt% (residual carbon content) one 58.6 29.0 6.4 2.8 3.6 0.09 2 70.1 16.7 6.8 2.7 3.8 0.10 3 81.1 8.7 3.6 3.2 3.7 0.08 four 85.4 5.8 1.7 3.2 3.7 0.08 5 * prototype 84.1 / 92.5 4.3 / 5.2 3.2 / 0.7 0.9 / 0.1 7.3 / 1.4 0.07

* In the numerator: prototype magnesite of the Satka deposit (after calcining at 1000 ° C); brucite in the denominator of the Kuldur deposit (after calcination at 1000 ° C).

Table 5.

Mineral (compound) name Chemical formula of the mineral (compound) Content, wt% Refractory (example 3, 4) Content, wt% Flux (example 162) Periclase + magnesite MgO + (Mg, Fe² ⁺ ) Fe ₂ ³ ⁺ O ₄ 87-90 57-60 Calcium ferritic + brownmillerite (Ca ₂ Fe ₂ O ₄ + Ca ₂ AlFeO ₅ ) 3-5 30-32 Alite + whitewash 3CaO⋅SiO ₂ + 2CaO⋅SiO ₂ 4-6 7-9 Graphite (residual) C <0.1 <0.1

Table 6.

Example of execution (composition) Material Sintering temperature, ° C Firing duration, min. Refractoriness, ° C Deformation start temperature, ° C Open porosity,% Solubility in slag,% Slag resistance (corrosion area), mm² one Declared agglomerate (flux) 1320 twenty 1640 1480 12.3 19.1 ------- 2 Also 1350 fifteen 1650 1490 eight 18.7 ------- 3 Declared agglomerate (refractory) 1400 25 1690 1550 18.4 6.3 16.3 four Also 1500 twenty > 1750 1650 6,7 5.8 15.4 five Prototype 1500 twenty > 1750 1650 16.9 6 15.7

Claims (12)

1. A charge for obtaining a refractory lime-magnesia-ferrous agglomerate containing a material containing calcium oxide, a material containing iron oxide, and a carbon-containing material in the form of a coke, characterized in that it additionally contains scrap of spent periclase-carbon refractories of fraction 0.1-20, 0 mm, as a material containing calcium oxide, a material containing at least 80 wt.% CaO, fractions of 0.1-1.0 mm was used, and as a material containing iron oxide, a material containing at least 80 wt. % Fe ₂ O ₃ , fractions 0.1-1.5 mm with the following content of components, wt.%: calcium oxide material 5-20 iron oxide material 3-6 koksik fraction 0.1-3 mm 3-5 waste scrap periclase-carbon refractories rest 2. A charge according to claim 1, characterized in that, as a material containing calcium oxide, ground lime and / or lime dust of roasting furnace units is used. 3. A charge according to claim 2, characterized in that, as a material containing iron oxide, ground mill scale and / or dust and sludge of blast furnace and / or steelmaking are used. 4. The charge according to claim 1, characterized in that the coke is used with an ash content of not more than 15 wt.%. 5. A method of producing a refractory lime-magnesia-ferruginous agglomerate from a charge according to claim 1, characterized in that the charge components are mixed, a two-layer charge of the charge is loaded onto the sintering surface of the grate and its agglomeration, while the scrap of spent periclase-carbon refractories is crushed before mixing , air-gravity classification with the release of products of fractional composition of 0.4-20.0 mm and 0.1-4.0 mm and carry out a separate two-layer stacking of the selected fractions of scrap on the sintering surface of the grate in the lower and upper layers of the charge, agglomeration is carried out in an oxidizing medium at a temperature of 1250-1350 ° C for 15-20 minutes until the residual carbon content is less than 0.1 wt.%, and 57-73 wt.% of the mentioned scrap of fraction 4.0-20.0 mm is loaded into the lower layer of the charge, and a mixture of the above-mentioned scrap of fraction 0.1-4.0 mm with the remaining components of the charge is placed in the upper layer at the following ratio, wt%: scrap fraction 0.1-4.0 mm 10-12 calcium oxide material 8-20 iron oxide material 5-6 coke 4-5 6. The method of claim 5, wherein a refractory lime-magnesia-ferruginous agglomerate is prepared for use as a steelmaking flux. 7. A method of producing a refractory lime-magnesia-ferruginous agglomerate from a charge according to claim 1, characterized in that the charge components are mixed, a two-layer charge of the charge is loaded onto the sintering surface of the grate and its agglomeration, while the scrap of spent periclase-carbon refractories is crushed before mixing , air-gravity classification with the release of products of fractional composition of 0.4-20.0 mm and 0.1-4.0 mm and carry out a separate two-layer stacking of the selected fractions of scrap on the sintering surface of the grate in the lower and upper layers of the charge, agglomeration is carried out in an oxidizing medium at a temperature of 1350-1500 ° C for 20-25 minutes until the residual carbon content is less than 0.1 wt.%, and the mentioned scrap of fraction 4.0-20.0 mm is loaded into the lower layer of the charge in the amount of 60-70 wt. %, and a mixture of the mentioned scrap of fraction 0.1-4.0 mm with the remaining components of the charge is placed in the upper layer at the following ratio, wt%: scrap fraction 0.1-4.0 mm 19-24 calcium oxide material 5-8 iron oxide material 3-4 coke 3-4 8. The method according to claim 7, in which a refractory calcareous-magnesian-ferrous agglomerate is obtained for use as a refractory material for the hearths and slopes of electric arc furnaces. 9. A method according to claim 5 or 7, characterized in that the lower and upper layers of the charge have a thickness of 23-25 cm each.