RU2280699C2 - Method of steel making in oxygen converter with slag remaining - Google Patents

Abstract

FIELD: ferrous metallurgy; methods of steel making in oxygen converters with slag remaining.

SUBSTANCE: proposed method includes remaining of molten slag of previous melting in converter, introduction of coolant and thickener on remaining slag, charging the scrap, pouring molten cast iron, lancing the bath with oxygen and introduction of fluxes and slag-forming materials in way of lancing. Used as coolant and thickener is composite material in form of pigs consisting of mixture of oxide-containing, carbon-containing and slag-forming materials filled beforehand with iron-carbon alloy; consumption of pigs of composite material ranges from 5 to 250 kg/t of slag.

EFFECT: enhanced safety of melting due to avoidance of emissions during pouring molten cast iron into converter and in the course of lancing; improved technological and economical parameters of melting process.

4 cl, 1 tbl, 17 ex

Description

The invention relates to ferrous metallurgy, specifically to an oxygen-converter process.

A known method of steelmaking in oxygen converters [1], including the filling of scrap metal, loading slag-forming materials, pouring molten iron, purging the bath with oxygen, introducing lime and other slag-forming materials and fluxes during the purging, the release of metal and slag. The disadvantage of this method is that the final slag of the converter smelting, which has the highest reactivity, is not used in the manufacture of steel. As a result, the components that form the slag and its heat content are irretrievably lost.

The closest in technical essence is the method of steel smelting [2], including leaving part of the liquid slag of the previous melting in the converter, thickening and cooling it with additives of a solid cooler and thickener (lime, dolomite and other slag-forming materials and fluxes), loading scrap metal, feeding it slag-forming materials and fluxes, pouring molten iron, purging the bath with oxygen, entering along the purge of slag-forming materials and fluxes, the release of metal, leaving part of the final slag.

This method of smelting partially eliminates the disadvantages of the above method, but does not allow the full use of the final slag.

The main disadvantages of this method are:

- the possibility of emissions when pouring molten iron on slag due to the explosive interaction of the carbon contained in it with the iron oxides of the slag left. The lack of safe working conditions is the main factor holding back the development of this method;

- uneven cooling and thickening of the slag with additives of slag-forming components, the density of which is lower than the density of the finished slag and does not ensure their proper mixing with liquid slag. This leads to the preservation of individual volumes of slag in the molten state and the subsequent occurrence of emissions;

- the amount of reagents introduced into the slag before the purge is started is limited to 20-50% of their total consumption for melting, which is insufficient to cool the slag to a solid state;

- not achieved the necessary reduction in the slag concentration of iron oxides. As a result, the likelihood of a violent reaction between the carbon of cast iron and the iron oxides of the slag and the appearance of emissions, including during purging, remains;

- insufficient slag deoxidation, which increases the loss of iron with slag and reduces the yield of liquid steel;

- a limited amount of slag left, which does not exceed 25% of the total amount of slag generated during smelting. If the amount of slag left exceeds this value, then when the bath is purged, emissions occur;

- the deterioration of environmental working conditions due to the additional burning of part of the lime and dolomite and the release of CO ₂ and other gases due to the heating of the cooler and thickener in contact with molten slag, as well as the increased removal of dispersed particles by the gases formed.

Taken together, these factors reduce the degree of possible use of the thermal and material potential of the final slag and all slag as a whole. In turn, this leads to the underutilization of the capabilities of the known method of smelting, reduction of technological and technical and economic indicators of smelting.

An object of the invention is to increase the safety of smelting by eliminating emissions when pouring molten iron into the converter and during purging, increase the relative amount of final slag left, improve the temperature and slag conditions of converter smelting in the early stages of purging, and also improve technological and technical and economic indicators of melting .

The technical result is achieved by the fact that in the method of steelmaking in an oxygen converter, which includes leaving the final slag of the previous melting, introducing a solid cooler and thickener onto the left slag, loading scrap metal, pouring molten iron, purging the bath with oxygen, introducing slag-forming materials and fluxes while purging the release of metal, leaving the final slag, as a solid cooler and thickener use composite material in the form of ingots, consisting of a mixture of oxide-containing, carbon-containing and slag-forming materials preliminarily filled with an iron-carbon alloy, the composite material is introduced into the slag of the previous smelting with a flow rate of 5-250 kg / t of slag.

In order to widen the change in the redox potential of the solid oxidizing agent and thickener introduced onto the slag, the possibility of changing their cooling ability and, on this basis, expanding the process control limits in the slag, in addition to the composite material, solid cast iron is used in a mixture with it in the ratio 1: (0 , 1-5), respectively.

To increase the degree of utilization of the final slag in the converter, 10-100% of the total mass of the slag formed in the smelting is left.

As the oxide-containing component of the composite material, iron ore, scale, sinter, iron ore pellets, concentrate, manganese-containing materials - ore, sinter, ferroalloy slag, sludge and / or mixtures thereof, and recycled slag, magnesium fluxes, etc. are used. an oxygen source for the oxidation of impurities of the metal base of the composite material and cast iron. At the same time, they partially fulfill the functions of slag-forming ingredients.

Carbon-containing components include coal, coke, silicon and calcium carbides, waste containing carbon, including blast furnace dust, sludge, etc. These materials play the role of reducing elements with respect to iron oxides in the slag left and, if necessary, the role of an additional energy carrier.

Slag-forming components and fluxes include lime, ferruginous lime, dolomitized lime, dolomite, fluorspar, manganese ore, manganese-containing materials, oxides and fluorides of alkaline-earth elements (sodium, calcium, magnesium), recycled slag, IMF fluxes like magnesium, IMF fluxes etc. They can be included in the composition of the composite material, and can be used in free form for direct input to the left slag and during purging.

The metal base of the composite material is iron-carbon alloys, namely, pig iron and an intermediate obtained after pre-cast iron pretreatment, as well as a carbon intermediate formed after removal of Ti, V, Si, Cr, Mn, P impurities from iron.

Composite material includes these components in their following ratio, wt.%:

oxide-containing materials 1-35 carbon containing 0.5-15 slag-forming 5-30 iron-carbon alloy (base) rest

The method is as follows. After the metal is finished and slag is left in the converter, the pigs of composite material in the amount of 5-250 kg per 1 ton of slag or a mixture of composite ingots and solid cast iron in a ratio of 1: (0.1-5) are loaded onto the left slag. Prior to loading metal coolers and thickener of liquid slag - composite and solid cast iron, or simultaneously with them, slag-forming materials, fluxes - lime, dolomite, manganese ore, magnesia fluxes and other slag-forming materials are fed to the slag in the amount of 5-90% of their total consumption. The composite ingots have a density of about 5-6.5 g / cm ³ , significantly higher than the density of liquid slag and the density of slag-forming materials and fluxes. Due to this, as well as a significant fall rate of the ingot of the composite or a mixture of composite and cast iron, they break through the slag layer and fall on the bottom of the converter. At the moment of their impact on the surface of liquid slag, on which slag-forming reagents and fluxes are located, the melt of the slag and the materials introduced onto the slag are mixed, as well as the latter is entrained inside the slag. Once inside liquid slag, ingots of a composite or a mixture of composite and cast iron, as well as slag-forming materials and fluxes, they quickly heat up, taking away heat from the slag. In this case, the slag cools, thickens and hardens with the formation of hardened conglomerate. After that, scrap is loaded onto chilled slag. The introduced materials additionally cool the already solidified slag, increasing the degree of cooling of this conglomerate. Iron oxides of slag, having passed from a liquid to a solid state, lose the ability to react violently with carbon of molten iron. Therefore, further cast iron casting on hardened slag is not accompanied by emissions.

In the process of casting iron, the outer surface of ingots, already preheated due to the heat of slag, is additionally heated to a temperature of molten cast iron (1300-1400 ° C), exceeding the melting temperature of cast iron (1150 ° C), and melts. At the same time, all impurities of the iron-carbon alloy, including carbon, begin to oxidize on the surface of the composite ingots and cast iron. Moreover, carbon oxidation proceeds at high rates of 0.1-0.3% C / min or more, which significantly exceeds the rate of carbon oxidation of molten iron in the initial periods of converter smelting. The carbon monoxide CO formed during this process, similarly to bottom blowing, mixes liquid metal and slag, accelerating heat and mass transfer processes in the converter bath, and serves as an additional source of heat due to its afterburning to CO ₂ . At the same time, when pouring molten iron into the converter, the slag-forming reagents and fluxes previously introduced into the scrap metal are heated. This contributes to a more rapid dissolution of them in the slag and accelerates the formation of slag.

During the purging process, hardened slag together with particles of slag-forming materials and fluxes breaks up into fragments as a result of mechanical hydrodynamic and thermal effects of scrap metal and molten iron. After the melting of the scrap metal protruding above the surface of the cast iron, the pieces of solid slag are melted by the high temperature of the reaction zone. Moreover, slag is quickly formed on the surface of the metal bath. Fluxes and slag-forming materials introduced into the slag and scrap metal, components released from the ingots of the composite after their melting, oxidation products of pig iron impurities and iron oxides formed in the reaction zone during the interaction of blast oxygen and cast iron enter this slag. As a result of mixing these components, an active highly reactive slag is formed, the state of which is maintained during the purging of the bath with oxygen by periodically introducing new portions of slag-forming reagents and fluxes.

During long-term continuous operation with the leaving of slag, sulfur and phosphorus accumulate in it, which can cause an increase in the content of these elements in the metal. Therefore, the slag is updated by changing for this purpose the amount of final slag left in the converter.

In the case of operation with complete abandonment of the final slag, solid coolers and thickeners are introduced into the slag before the slag is drained from the converter. After 1-5 minutes from the start of the input, a portion of the final slag is downloaded. Next, the initial portion of scrap metal is introduced into the left hardened slag, liquid iron is poured and the bath is purged with oxygen. In this case, the cold materials introduced into the slag are heated more strongly from the slag. Due to this, the heat efficiency of the final converter slag is increased. Due to this, the temperature of the solid-liquid bath before blowing begins to be higher, which increases the dissolution rate of lime and other fluxes in the slag and accelerates the formation of a physically uniform and active slag with increased basicity. At the same time, due to a higher degree of heating of the outer surface of the ingots of the composite and cast iron, the amount of molten cast iron and, consequently, the amount of carbon and other reducing elements introduced into the slag by composite and cast iron increase. Due to this, the reduction of iron from iron oxides and slag is enhanced. In turn, this increases the slag deoxidation, which reduces the risk of emissions and at the same time increases the extraction of iron from the slag and, in general, the yield of iron. The carbon monoxide released during this process, which is a product of the interaction of carbon and iron oxides of the composite material, burns out in the atmosphere of the converter, providing an additional and at the same time controlled heat influx.

Ingots of material or their mixture with cast iron are loaded into the slag left at the same time as the supply of slag-forming reagents and fluxes, or after the introduction of these materials. The total amount of components introduced into the slag is 5-90% of the total consumption for smelting.

This allows you to enter the specified amount of slag-forming components and fluxes into the converter before starting the purge and provide earlier slag formation and improve the thermal and temperature conditions of the smelting. Pieces of solid materials, falling on the slag, coated with a layer of fluxes, carry the fluxes deep into the liquid slag, thereby contributing to the mixing of liquid slag and input materials, thickening and uniform cooling of the slag. The main result of this technique is the possibility of a quick and guaranteed transition of slag from molten to solid and the formation of a uniform solid mixture of slag, slag-forming fluxes, ingots of composite material or ingots of composite and cast iron. This accelerates the heat and mass transfer processes in this mixture and prepares it for the subsequent formation of physically and chemically homogeneous active slag from it.

The input to the molten slag of the ingots of composite material left in the converter is carried out in an amount of 5-250 kg / t of slag. Additives of cold solid material cause cooling of the liquid slag and its thickening, as a result of which the intensity of the interaction of iron oxides in the slag with the carbon of molten iron poured into the converter decreases sharply. This prevents emissions from the converter when casting iron. The ingots of the material are intensely heated by liquid slag due to the relatively large specific surface area and the high temperature difference of the input material and slag. In combination with a lower melting temperature of the material, this ensures quick heating of the surface of the ingots before melting and the flow of molten iron flowing from the surface of the ingots into the slag. Impurities of cast iron - carbon, silicon and manganese - reduce iron oxides, thereby reducing their content in the slag left. As a result, the possibility of a violent reaction between the carbon of cast iron and slag oxides and the appearance of emissions is further reduced. Reduction of iron from slag oxides increases iron recovery and yield of liquid metal.

Additives of material on slag in the range of 5-250 kg / t of slag completely eliminate the risk of emissions both during the casting of pig iron into the converter and during the purge of the bath, as well as provide additional extraction of iron from the slag.

When the amount of material is less than 5 kg / t of slag, the cooling of the slag and the degree of its deoxidation are relatively small and do not provide sufficient cooling, thickening of the slag and reduce its oxidation. As a result, the likelihood of outbreaks increases. To combat this phenomenon, it is necessary to reduce the rate of pouring liquid iron into the converter, which worsens the performance of the proposed method, especially the duration of the first purge period, steel yield, and slag formation rate. Therefore, reducing the consumption of material below 5 kg / t is impractical.

If the amount of input material exceeds 250 kg / t of slag, the cooling of the slag is excessive. At the same time, the amount of solid material in the converter increases significantly. To heat this material, the supply of heat in the slag is not enough. As a result of this, the process of transition of the hardened slag and material to a liquid state is delayed. This worsens the conditions for the formation of slag in the initial purge period and leads to emissions during the purge process. These factors limit the upper limit of this parameter. Therefore, in the proposed method, the range of flow rates of the material 5-250 kg / t is the most rational and ensures the achievement of the maximum possible effect.

Composites of composite material can be introduced onto slag together with solid cast iron in a ratio of 1: (0.1-5), respectively. This additionally allows to widely control the carbon-oxygen ratio in the mixture of material and solid cast iron, depending on the composition and amount of slag left, as well as the redox properties and cooling effect by combining the properties of the ingots of material and cast iron. The presence of ingots of material in this mixture ensures the bubbling of slag by gases as a result of the reaction between carbon and oxides in this material, as well as the addition of additional heat as a result of afterburning of CO to CO ₂ above the slag. Boiling and mixing slag with gas bubbles accelerates heat transfer between the ingots of material and solid iron on the one hand and liquid slag on the other, and also prevents the ingots of material and solid iron from fusing into a single refractory monolith, thereby ensuring quick heating of the materials and rapid cooling of the slag after the start of purging . Solid iron as a result of partial melting of its surface and the formation of liquid melt serves as an additional source of elements that deoxidize slag.

The main result of the joint use of ingots of material and solid cast iron is the simultaneous achievement of a quick conversion of slag from liquid to solid and its deoxidation by the elements that make up cast iron, as well as the possibility of additional heat due to afterburning of CO to CO ₂ above the slag.

The combined use of ingots of material and solid cast iron increases the number of coolers supplied to the slag and their total amount compared to cooling the slag with slag-forming materials and fluxes. At the same time, this facilitates the task of synchronizing the processes of slag cooling before casting and casting it back to liquid after casting and starting to purge.

If the ratio is less than 1: 0.1, then the effect of additional cooling of the slag, the supply of reducing elements from cast iron to slag and deoxidation of the latter is weak and the introduction of solid cast iron loses its meaning. If the ratio is taken more than 1: 5, then excessive cooling of the slag occurs, the proportion of solid metallic material in the charge increases and the flow of carbon into the bath increases. To melt an additional amount of solid cast iron and remove carbon from it, time and oxygen consumption are required, which affects the heat balance of the heat and the performance of the proposed method. In addition, there is a danger of overheating of the final metal above the permissible level.

It is proposed in the converter to leave 10-100% of the final slag instead of 25% or less according to known technology, which ensures its more complete use. The upper limit - 100% - refers to the case of using pre-refined chemical and physically cold cast iron or intermediate, when the amount of slag formed sharply decreases - up to 30-60 kg / t of liquid steel.

The lower limit - 10% - refers to the case of smelting low- and especially low-carbon pure steels, in the smelting of which the amount of slag formed increases significantly and reaches 150-200 kg / t of liquid steel. If the amount of slag left is less than 10%, the effect of the proposed method will be insignificant due to the relatively small amount of slag involved in the reuse (not more than 3-6 kg / t of steel).

Therefore, the limits of 10-100% are the most rational from the point of view of maximizing the potential of converter slag. At the same time, these limits ensure slag renewal during continuous continuous operation of the converter, leaving slag left. The need for this is due to the accumulation of sulfur and phosphorus in the final slag and the danger of obtaining a high content of these elements in the metal at the end of the purge.

Composites of composite material or their mixture with cast iron can be introduced both on the slag left after a preliminary download of part of it, and before removing the slag from the converter, when the amount of slag is maximum. In the latter case, the total consumption of introduced coolers increases, which allows to increase the degree of heat and iron utilization of the final slag and slag as a whole. The composite ingots introduced into the converter or their mixture with solid cast iron in this case are heated more strongly, as a result of which slag is actively deoxidized and iron is reduced from oxides. As a result of this, the extraction of iron from the slag increases and its tendency to violently interact with the carbon of cast iron when it is poured decreases. The CO and CO ₂ slag formed during the reaction of carbon and iron oxides intensively mix the slag, increasing the rate of its heat exchange with ingots of composite material or its mixture with solid cast iron. After 1-5 minutes after entering the material or its mixture with solid cast iron into the converter, part of the slag is removed to the required level. During the download process, heat and mass transfer of these materials to the slag continues, which ensures a more complete course of these processes. After the slag part is drained, slag-forming materials and fluxes are loaded onto the left liquid slag, a new portion of the composite or a mixture of composite and solid cast iron is introduced and scrap metal is loaded, a portion of slag-forming materials and fluxes is introduced, cast iron is poured, the bath is purged with oxygen, etc.

An example of a specific implementation. Solid ingots of composite material were made on a continuous casting machine equipped with additional devices and containers for receiving the initial components, feeding these components to the machine, and a dosing system for the casting molds (molds) of the casting iron casting machine.

Before pouring liquid metal melt into the casting molds, the initial iron ore components were loaded having a fraction size of 5–25 mm, in an amount providing billets with a total filler content of 5 to 50 wt.%.

The lightest component of the composite — the carbon-containing component — was pre-agglomerated together with iron oxides using cold briquetting. This made it possible to increase the density of the carbon material and its uniform distribution in the pig body. The casting molds filled with fillers were poured with iron-carbon melt, the role of which was carried out by liquid pig iron or an intermediate product of non-baked cast iron processing. During the movement of the conveyor with casting molds located on it, the mixture of molten iron and fillers was cooled from the inside by the components introduced into the melt and solidified. To accelerate solidification, the upper outer surface of the ingots in contact with the surrounding atmosphere was cooled with water. The resulting material in the form of ingots was supplied in solid form to an oxygen-converter shop.

After the purge and release of the liquid metal was completed, lime and dolomite were added to the left liquid slag (10-100%), and then composite material or a mixture of this composite and cast iron was introduced. As a result of exposure to cold materials, the liquid slag was cooled, thickened and transformed from liquid to solid. In this case, a conglomerate was formed in the converter, consisting of composite ingots or composite ingots and cast iron, cooled slag, slag-forming materials and fluxes mixed into the slag when the ingots fell on the surface of the slag melt. After that, scrap was loaded into the converter, molten iron was poured, and the bath was purged with oxygen from above. During the loading of scrap and pouring molten iron, most of the conglomerate formed was crushed into separate fragments consisting of a mixture of hardened slag, slag-forming fluxes, composite ingots or a mixture of composite ingots and solid iron. These fragments after pouring cast iron, the beginning of purging and penetration of scrap metal surfaced on the surface of cast iron. The ingots of the composite, having a density close to molten iron, remained in the molten iron, gradually separating from the bottom of the converter and floating up to the surface of the metal bath. Cast iron ingots, if used together with the composite, remained on the bottom of the bathtub. After ignition of the melting and melting of scrap metal protruding above the surface of cast iron, the oxidation of silicon, manganese, part of iron and the addition of scrap in the volume of molten cast iron were performed. At the same time, slag was induced using the products of oxidation of pig iron elements - iron, silicon and manganese, left slag from the previous smelting, slag-forming and fluxes introduced to the left slag, as well as slag-forming components released from the composite after its melting. High temperatures of the reaction zone and forming iron oxides accelerated the melting of the solid, but hot mixture of slag left in the converter and coolers and thickeners introduced into it and ensured the rapid formation of homogeneous highly active slag. Then, using induced slag and a melt formed from a mixture of molten iron, molten scrap and molten ingots of a composite or composite mixture of solid cast iron, intense carbon oxidation was performed. The basicity of the slag, the content of magnesium oxide in it, and other parameters of the slag and slag regime were regulated by the flow of bulk slag-forming materials and fluxes. The oxygen purge rate was maintained at 2.9-3.1 m ³ / (min · t). After reducing the carbon concentration in the metal to the level of 0.05-0.10% and heating the metal to a temperature of 1650-1680 ° C, the purge was stopped and the metal was released, leaving 10-100% of slag in the converter. Next, the ingots of the composite or its mixture with solid cast iron, slag-forming materials and fluxes were planted on the slag left. The ingots of the composite provided intensive mixing of the liquid slag with CO bubbles formed as a result of the interaction of carbon and oxygen present in the composite. After the transition to the molten state, the carbon of the metal base of the composite and cast iron reacted with iron oxides, deoxidizing the slag and reducing iron from the slag oxides. The ratio of the amount of carbon coming from the composite and solid iron for slag deoxidation was controlled by changing the total consumption of these materials and the ratio of their shares. To remove the technological characteristics of the blast and slag regime, smelting was carried out with intermediate slag downloading.

The table shows examples of the method of steelmaking in a converter with various technological parameters according to the proposed method and the known (prototype).

In optimal examples 2-7, due to cooling and thickening of the slag left by the composite material, the basis of which is metal in the form of an iron-carbon alloy and mineral fillers, or by a mixture of material and solid cast iron, safe melting conditions are achieved, an increase in the amount of final slag left, an improvement in melting indices.

The results of calculations and industrial tests with technological parameters varying over a wide range have confirmed that the proposed technology ensures, due to better cooling of the slag left and the level of oxidation of this slag, a smooth melting process without emission when pouring molten iron into the converter and during decarburization of the bath, increasing the bath temperature in the pre-purge period and in the first initial purge period by 50-150 ° C, the acceleration of lime dissolution and the formation rate went ka, increased intensity of refining cast iron from carbon, sulfur and phosphorus in the initial period of blowing and smelting in general, as well as higher yield, lower and more stable oxidation of slag and metal, the purity of the final metal in sulfur, phosphorus and non-metallic inclusions, more complete use of final converter slag.

According to the proposed technology, an increase in the rate of dissolution of lime into slag from 80 to 110-138 kg / min, an increase in the degree of phosphorus removal from 72 to 83.9-93.5%, and sulfur from 49 to 52.8-56 are provided in the initial purge period. ,one%; reduction of lime consumption by 4.3-11.6 kg / t, dolomite - by 6.9-9.4 kg / t, fluorspar by 0.4-1.8 kg / t, reduction of slag oxidation by 1.5 -4.8% abs., Metal oxidation from 0.075 to 0.050-0.069, increase in the residual manganese content from 0.05 to 0.08-0.15%. In the experimental melts carried out according to the proposed technology, the consumption of cast iron decreased from 835.6 to 823.8-827.5 kg / t, the duration of the initial period decreased by 2.1-3.5 minutes, the yield increased by 0.4- 1%, the average proportion of swimming trunks with a phosphorus content of not more than 0.012 and sulfur no more than 0.016% increased from 57.2 to 78.3%, and the consumption of shotcrete mass decreased from 2.61 to 2.38-2.54 kg / t

Indicators swimming trunks using the proposed and known method

Indicators Examples Prototype one 2 3 four 5 6 7 8 one 2 3 four 5 6 7 8 9 10 1. The specific consumption of composite material for cooling the left slag, kg / t of slag 4.6 5.2 21 48 73 95 100.3 115 - 2. The ratio of the proportions of the composite material and solid iron, introduced to the left slag 1: 0.06 1: 0.11 1: 2 1: 4 1: 3,5 1: 4 1: 5.2 1: 6.1 - 3. The relative amount of slag-forming and fluxes introduced into the converter before the filing of the composite material or its mixture with cast iron,% 4.6 6.1 18.3 31.8 49.1 69.7 87.5 91 - 4. The amount of slag left in the converter,% of the total amount formed during the smelting 23 27 37 39 41 47 51 59 21.5 5. Temperature of cast iron, ° С - before starting purge 1170 1210 1230 1280 1315 1333 1317 1280 1100-1150 - after 30% of the purge time 1350 1361 1365 1376 1385 1396 1408 1391 1340 6. The degree of removal of phosphorus and sulfur, respectively in the initial period 78 83.9 87.2 93.5 92.6 91.4 90.8 88.3 72 purge (from the moment of its beginning to the intermediate download of slag),% 52.1 52.8 53.1 54.3 56.1 54,2 53.1 51.8 49 7. Start time for downloading intermediate slag,% of the smelting time 42 40.5 38 36 35 33 31 29th 60-75 8. The rate of dissolution of lime in the initial period of purging to the intermediate download of slag, kg / min 94 119 130 138 131 124 119 111 80

one 2 3 four 5 6 7 8 9 10 9. Change in the degree of oxidation of sulfur in the initial period of smelting 1.25 1.40 1,52 1,62 1,67 1,59 1.49 1.29 one 10. The proportion of heats,%: with a content of ≤0.012% [P] and ≤0.016% [S] 65 69 76 79 83.5 88.9 78.6 72.8 57.2 11. Specific consumption of slag-forming materials and fluxes, kg / t: - lime 60 52,5 49.8 46.1 45,2 47.2 49.1 50,5 56.8 - dolomite 10 13 12 12 eleven 13 13.5 12 20,4 - fluorspar 1,0 1.4 1,1 0.5 - - 0.5 0.4 1.8 12. Oxidation,%: - final slag 22.0 19.9 18.0 18.1 18.0 19.6 20.1 21.3 22.8 metal on release 0,07 0,061 0,053 0,050 0.051 0,055 0,061 0,069 0,075 13. The residual content of manganese in the metal at the issue,% 0.06 0.08 0,085 0.09 0.13 0.15 0.12 0.10 0.05 14. Specific consumption of molten iron, kg / t 828.4 827.5 826.5 826.5 825.2 823.8 825.1 825.5 835.6 15. The duration of the initial melting period, min 2.1 2.6 3,1 4.0 3,5 3.8 3.3 2.7 4.4 16. The output of liquid steel,% 89.1 89.3 89.4 89.5 89.9 89.9 89.5 89.3 88.9 17. Specific consumption of shotcrete mass, kg / t steel 2,57 2.54 2,51 2.47 2,39 2,38 2.41 2.45 2.61

Information sources

1. Kravchenko Yu.S. and others. Steelmaker of converter production. - M.: Metallurgy, 1991, p. 53-54.

2. Steel production technology in modern converter shops. S.V. Kolpakov, R.V. Starov, V.V. Smokty et al. / Under the general ed. S.V. Kolpakova. - M.: Mechanical Engineering, 1991, p. 81-82.

Claims (4)

1. The method of steelmaking in an oxygen converter, including leaving the final slag of the previous melting, introducing a solid cooler and thickener, including lime, loading scrap metal, pouring molten iron, purging the bath with oxygen, introducing slag-forming materials and fluxes along the blast, the release of metal and slag, leaving the final slag, characterized in that as a solid cooler and thickener use composite material in the form of ingots, consisting of a mixture of oxide-containing, carbon-containing it and slag-forming materials, previously filled with an iron-carbon alloy, while the composite material is introduced into the slag with a flow rate of 5-250 kg / t of slag. 2. The method according to claim 1, characterized in that in addition to the composite material, solid cast iron is used in a mixture with it in a ratio of (0.1-5): 1, respectively. 3. The method according to claim 1, characterized in that liquid slag is left in the converter in an amount of 10-100% of the total mass of slag formed on the smelting. 4. The method according to any one of claims 2 and 3, characterized in that the composite material or a mixture of composite material with cast iron is introduced into the slag before it is released from the converter.