UA120663C2 - METHOD OF EXTRAORDINARY DESULFURATION OF IRON - Google Patents

Abstract

The invention relates to the field of ferrous metallurgy. The method of out-of-furnace desulfurization of cast iron includes the formation in the first phase of ladle slag with a basis of 0.8-1.0, for which is blown into the melt to a depth of 0.3-0.5 m by co-injection in a ratio of 3: 1-5: 1 calcium-containing reagent and sodium-containing additive and / or alloy of waste sulfate and sodium carbonate, in the second phase reduce the sulfur content in the cast iron to 0.030-0.035 wt. %, for which the melt to a depth of 0.15-0.25 m from the bottom of the ladle is injected by co-injection of calcium and sodium-containing reagents in a ratio of 20: 1-20: 1.6 and simultaneously introduce aluminum wire, and in the third phase of processing is reduced sulfur content in cast iron to 0.001-0.020 wt. %, for which a magnesium-containing reagent is injected into the melt by monoinjection, while in the process of the whole treatment a protective gas is supplied to the surface of the melt with a flow rate of 20-40 m3 / h · m3. The invention increases the efficiency of the desulfurization process.

Description

The invention belongs to the field of ferrous metallurgy, in particular to the out-of-furnace processing of cast iron and can be used for desulfurization of cast iron in ladles of different capacities.

Known methods of out-of-furnace desulfurization of cast iron with magnesium, calcium-containing reagents and mixtures based on them can maintain the required level of cast iron desulphurization, however, due to wide fluctuations in the initial conditions of the processed melt, these methods are not characterized by high stability in achieving the specified final sulfur content in cast iron and, as a result, require increased costs of reagents.

There is a known method of off-fire processing of liquid metal (ASSR 1014910 A, С21С 1/02, publ. 04/30/1983), which includes blowing a magnesium-containing reagent into the flow of the gas carrier through a nozzle immersed in the melt.

The main disadvantage of this method is the use of only magnesium-containing reagents, which limits the scope of its application and does not ensure its universality.

The closest in terms of technical essence and attainability of the result is the method of processing molten blast-furnace iron in a ladle (patent KO 2096484, C1 MPK C21S 1/02, publ. 20.11.1997), which includes in the first phase of processing the formation of the main ladle slag by introducing it into the melt through a tuyere , which sinks, a reagent containing calcium, in the flow of the transporting gas, in the second phase of desulfurization of molten iron by the introduction of at least one reagent and the introduction of calcium-containing reagents and fluxes in the third phase of processing.

In a known method for improving the results of desulfurization of cast iron in the first phase of processing, the main slag is introduced by blowing in calcium-containing or aluminum-containing reagents in an amount corresponding to the sulfur content in the melt. The disadvantage of such a solution is the increased consumption of reagents for the formation of the main ladle slag and, as a result, an increase in the loss of iron with the slag that is additionally formed.

In addition, the known method in all three phases of processing does not provide for the creation of a non-oxidizing gas atmosphere over the melt, which is one of the important components of preparing the "cast iron-slag-gas atmosphere" system for the effective flow of desulfurization processes, which also leads to increased consumption of reagents and reduces the probability of reaching the specified final sulfur content in cast iron.

The second phase of processing in the known method also requires excessive consumption of reagents.

For example, during monoinjection of lime-containing reagents, the use of activating additives is not provided. And during co-injection into the melt in the second phase of processing magnesium together with a calcium-containing reagent, part of the magnesium is spent on interaction with oxygen (even in the case of using carbide, which contains calcium carbonates, oxides and bases).

The use in the known method in the third phase of processing of gas-emitting solid substances or fluxes, which are blown into the flow of the transporting gas, when the cast iron is already desulfurized with magnesium- and calcium-containing reagents to the required final sulfur content, leads only to washing out of the cast iron residual magnesium, which, as is known, creates a barrier for resulfurization of cast iron.

In addition, the use of fluxes in the third phase of processing also contributes to the resulfurization of cast iron, since metal "beads" are returned from the slag to the cast iron, which contains the main amount of sulfur that previously entered the slag. Therefore, the use of gas-emitting substances and fluxes in the final processing phase reduces the effectiveness of the known method and does not ensure the stability of the results achieved.

The task is to ensure the stability of obtaining the required final sulfur content and to increase the efficiency of the desulfurization process during out-of-furnace desulfurization of cast iron with various reagents.

The problem is solved by the fact that during the processing of molten blast-furnace iron in a pouring ladle, which includes in the first phase of processing the formation of the main ladle slag by introducing the appropriate reagent into the melt through a plunging nozzle, in the flow of the transporting gas, in the second phase of processing, the desulphurization of molten iron by introducing at least one reagent, and the introduction of reagents in the third phase of processing is provided in the first phase of the formation of ladle slag with a basicity of 0.8-1.0, for which it is blown into the melt to a depth of 0.3-0.5 m by the method of coinjection in a ratio of 3:1 -5:1 calcium-containing reagent and sodium-containing additive and/or an alloy of waste sulfate and sodium carbonate, in the second phase, the sulfur content in cast iron is reduced to 0.030-0.035 wt. 95, for which calcium- and sodium-containing reagents in the ratio of 20:1-20:1.6 are blown into the melt to a depth of 0.15-0.25 m from the bottom of the ladle by the method of co-injection and aluminum wire is simultaneously introduced, and in the third phase of processing sulfur content in cast iron up to 0.001-0.020 wt.95, for which a magnesium-containing reagent is blown into the melt by monoinjection, while in the process of the entire processing, a shielding gas (compressed nitrogen or argon, or natural gas) is supplied to the surface of the melt with a 60 flow rate of 20-40 mz /hour: m3.

Adjusting the gas atmosphere above the melt by feeding it to its surface under the lid of the ladle of shielding gas with a flow rate of 20-40 mz/h.m3 in each of the three phases makes it possible to largely exclude the negative influence of oxygen in the gas atmosphere on the additional oxidation of iron and slag components, i.e. .parts of iron, silicon and magnesium.The creation of an oxygen-free atmosphere above the melt ensures the stability of obtaining the required final sulfur content and increases the efficiency of the desulfurization process.

Either compressed nitrogen, or argon, or natural gas can be used as a protective gas to adjust the composition of the gas atmosphere. The required consumption of shielding gas depends on the type of gas carrier, the amount of bucket slag and the manufacturability (turbulence) of the reagent blowing process.

When argon and natural gas are used as protective gases and when there is a relatively large amount of ladle slag in the ladle (21 95 from the mass of cast iron), as well as when the process is calm, the supply of protective gases to the surface of the melt with a flow rate of 20 mZ/h.em3 provides a stable non-oxidizing composition of the gaseous atmosphere. It is impractical to reduce the consumption of shielding gas below 20 mz/h.mu, as atmospheric air suction begins.

When using nitrogen as a protective gas and when there is a relatively small amount of ladle slag in the ladle ("1 95 from the mass of cast iron), as well as when the process is quite intensive, it is necessary to supply a protective gas with a flow rate of 40 m3/h.m3. It is impractical to increase the consumption of shielding gas by more than 40 m3/h.m3, taking into account the growth of processing costs.

The introduction in the first phase of processing under the surface of the melt in addition to the calcium-containing reagent by the method of co-injection of a sodium-containing additive in a ratio of 3-5:1 until the basicity of the ladle slag is reached 0.8-1.0 allows, firstly, to increase the sulphide capacity of the ladle slag due to the introduction of calcium compounds, and, secondly, to remove metal inclusions from the slag due to the introduction of sodium compounds. Thus, the adjustment of the composition of the ladle slag, performed in the first phase of processing with the use of a sodium-containing additive in addition to the calcium-containing reagent, ensures the stability of obtaining the required final sulfur content and increases the efficiency of the desulfurization process.

At the same time, the introduction of reagents in the first phase of processing under the surface of the melt to a depth of 0.3-0.5 m allows this operation to be performed technologically, without splashes, without washing out the lining

From a bucket and without significant energy costs.

The introduction of the tuyeres into the melt to a depth of 0.3 m is carried out when the processing of cast iron is carried out in ladles with a relatively small surface area of the melt (2.5-3.5 m"), if there is liquid slag in them and in a small amount ("0, 5 95).The introduction of reagents to a depth of no more than 0.3 m worsens the conditions of mass transfer in the "slag-metal" system and leads to a lengthening of the operation for adjusting the composition of the bucket slag.

The introduction of the lance into the melt to a depth of 0.5 m is carried out when the processing of cast iron is carried out in ladles with a relatively large surface area of the melt (3.6-12.5 m), if they contain a large amount of slag (51 95) in the form of dry heterogeneous conglomerate The introduction of reagents to a depth of more than 0.5 m is impractical due to the increased turbulence of the process of blowing reagents, the occurrence of splashes, as well as the appearance of a prerequisite for washing the lining.

The introduction of calcium-containing and sodium-containing compounds with a high ratio of 3:1 into the melt in the first phase of processing is used when the ladle slag is a dry heterogeneous conglomerate with a high content of metal inclusions (Remet. 240 95). It is impractical to increase the ratio of calcium- and sodium-containing compounds in the mixture to more than 3:1, since the lining of cast iron ladles begins to erode.

The introduction of calcium-containing and sodium-containing compounds with a low ratio of 5:11 into the melt in the first phase of processing is used when the ladle slag is mainly a liquid phase, and the content of metal inclusions in it is relatively low (Remet «40 95). It is impractical to reduce the ratio of calcium- and sodium-containing compounds to less than 5:11, as this prolongs the processing process.

The basicity of ladle slag is maintained at a level close to 0.8 when the amount of sulfur removed from cast iron is relatively small (A5-0.04 905), and the amount of ladle slag is quite large (21 95). It is impractical to have the basicity of ladle slag less than 0.8, as the possibility of resulfurization processes with the transfer of sulfur sulfides from slag to cast iron is not excluded.

The basicity of ladle slag is maintained at a level close to 1.0, when the amount of sulfur removed from cast iron is quite large (А5З»0.04 95), and the amount of ladle slag is relatively small («1 95). It is impractical to increase the basicity of bucket slag more than 1.0 due to unjustified overuse of calcium-containing reagents.

Thus, adjusting the composition of the ladle slag in combination with adjusting the composition of the gas atmosphere already in the first phase of processing ensures the preparation of the melt for the effective flow of desulfurization processes, which allows you to reliably predict the required consumption of reagents for desulfurization and achieve the specified final sulfur content in cast iron with high stability.

In the second phase of processing, the introduction into the melt of a calcium-containing reagent with an activating sodium-containing additive by the method of co-injection in the ratio of 20:1-20:1.6 and with the simultaneous introduction of aluminum wire into the melt with a triba apparatus, in an amount that ensures the deoxidation of the melt, allows to increase the efficiency of the use of the calcium-containing reagent and the stability of obtaining a given sulfur content in cast iron.

The introduction into the melt in the second phase of processing of calcium-containing compounds with the content of sodium-containing compounds - close to 20:11 and with the simultaneous introduction of aluminum wire into the melt is used when the ladle slag is mainly a liquid phase. It is impractical to reduce the ratio of calcium- and sodium-containing compounds to less than 20:1, since the effectiveness of the activating sodium-containing additive for the desulfurization process decreases, especially in the conditions of deep desulfurization, and also increases the loss of cast iron with the slag that is additionally formed and increases the loss of cast iron temperature.

The introduction into the melt in the second phase of processing of calcium-containing compounds with the content of sodium-containing compounds - close to 20:1.6 and with the simultaneous introduction of aluminum wire into the melt is used when the ladle slag is a dry heterogeneous conglomerate. It is impractical to increase the ratio of calcium- and sodium-containing compounds to more than 20:1.6, since the rapidity of the introduction of reagents increases to a technologically unacceptable level.

The introduction of calcium, sodium and magnesium reagents in the process of the second and third phases of processing to a depth of 0.15-0.25 m from the bottom of the ladle makes it possible to effectively use these reagents, since at the same time favorable conditions for mass transfer in the volume of the melt bath are provided. the longest duration of interaction of reagents with cast iron sulfur is achieved, and in the third phase of processing, when monoinjection of magnesium is carried out, the most favorable conditions for its dissolution in cast iron are provided.

It is impractical to introduce lances into the melt to a depth of no more than 0.15 m from the bottom of the ladle, since in

In this case, the washing effect of the two-phase flows flowing from the nozzles on the lining of the bottom of the bucket is not excluded. The upper limit of the introduction of the lance to a depth of 0.25 m from the bottom of the ladle is limited by the possibility of practically ensuring a higher accuracy of stopping the lance with devices for introducing lances into the melt.

The introduction in the third phase of processing into the melt by the method of monoinjection of a magnesium-containing reagent without additives containing compounds with oxygen excludes possible losses of magnesium due to interaction with oxygen, which ensures the stability of obtaining the required final sulfur content and increases the efficiency of the desulfurization process.

The drawing schematically shows an example of a processing course that includes three phases.

In the first phase of processing, powdered lime is injected under the surface of the melt by the co-injection method at a rate of 70 kg/min. and granulated soda at a rate of 17 kg/min.

In the second phase of processing, powdered lime is injected deep into the melt using the co-injection method at a rate of 87 kg/min., and granulated soda at a rate of 5 kg/min. and aluminum at a rate of 30 kg/min.

In the third phase of processing, magnesium (without additives) is injected deep into the melt.

In the process of all three processing phases, the composition of the gas atmosphere above the melt is adjusted by blowing compressed nitrogen with a flow rate of 40 m3/h.m3.

The proposed method of post-furnace desulfurization of cast iron is carried out as follows.

To implement the proposed method, a universal automated cast iron desulfurization unit is used, which implements the method of co-injection of calcium- and sodium-containing reagents and the method of monoinjection of magnesium without additives. The installation is equipped with a nozzle for blowing a mixture of calcium- and sodium-containing reagents, a nozzle for blowing magnesium without additives and a tribaparatra for introducing aluminum wire into the melt.

Technological operations of blowing desulphurized reagents into cast iron are carried out in the following sequence.

The first phase of processing.

Preparatory operations are performed and the nozzle for blowing calcium- and sodium-containing reagents is set into working position.

The transported gas is supplied to the dosing hoppers of calcium- and sodium-containing reagents, and a given initial pressure is created in them. At the same time, the nozzle for blowing calcium- and sodium-containing reagents is lowered to the position "above the melt" and the supply of shielding gas to the surface of the melt is opened with a flow rate of 20-40 m3/h.m3.

Then the shut-off and regulating apparatus for supplying the transporting gas to the nozzle and the valve for issuing the calcium-containing reagent are opened. The control valves set the intensity of supply of the calcium-containing reagent for the first phase of processing and the specified flow rate of the transporting gas, after which the nozzle is lowered into the melt to a depth of 0.3-0.5 m. To dispense the sodium-containing reagent, the shut-off and regulating equipment is opened on its dosing hopper and the intensity of the supply of the sodium-containing reagent is gradually increased to the specified value, which ensures the necessary ratio of calcium and sodium-containing reagents within the range of 3:1-5:71.

Co-injection of a mixture of calcium- and sodium-containing reagents is carried out before the injection of portions of these reagents specified in the first phase into the melt. This completes the first processing phase.

The second phase of processing.

The regulating devices of the hoppers-dispensers of calcium- and sodium-containing reagents set the intensity of the supply of reagents specified for the second phase of processing in compliance with the specified ratio within the range of 20:1-20:1.6, after which the nozzle is lowered into the cast iron at a distance of 0.15-0.25 m from the bottom of the bucket. In the process of co-injecting a mixture of calcium- and sodium-containing reagents into the melt, rod aluminum is introduced with a tribaparatra in the amount that ensures the deoxidation of the melt. After introducing into the melt the portions of reagents specified in the second phase, the supply of the sodium-containing reagent is closed and the nozzle is raised to the position "above the melt". Then the supply of the calcium-containing reagent, the transporting gas is closed, the nozzle is raised to the upper position and the shut-off and regulating apparatus is transferred to the initial position. This completes the second processing phase.

The third phase of processing.

A nozzle for blowing a magnesium-containing reagent is installed in the working position.

Transporting gas is supplied to the hopper-doser of the magnesium-containing reagent and a given initial pressure is created in it. At the same time, the nozzle for blowing the magnesium-containing reagent is lowered to the position "above the melt".

To feed the magnesium-containing reagent into the molten metal, the shut-off and regulating device for supplying the transporting gas to the lance is opened, then the reagent release valve is opened and the lance is lowered into the cast iron at a distance of 0.15-0.25 m from the bottom of the ladle. Turn on the rotary feeder, the intensity of the reagent supply is smoothly adjusted from 0 to the specified value. After blowing into

From the cast iron of a given portion of the magnesium-containing reagent, the rotary feeder is turned off and the lance rises to the position "above the melt". The supply of transporting gas is closed, the nozzle is raised to the upper position, the blowing of protective gas to the surface of the melt is turned off, and the shut-off and regulating equipment is transferred to the initial position.

After the final operations are completed and the pig iron ladles are sent to the customer, the processing process ends.

Table 1

Processing results and achieved technical and economic indicators during out-of-furnace desulfurization of cast iron according to patent KO 2096484 and according to the invention that is claimed. about, Examples of treatments according to the KO patent Examples of treatments according to

Mo | Technical and economic indicators 2096484 of the invention, which p/p and factors are claimed 111111 211111111171113 | 41516 1 7 | 8 | 9 6 (Initial Store, 95 | 0,036 | 036 | 042 | 0.036 | 0,046 | 040 | 040 | 046 | 040 8 aphas. | 105 o Duration of inhalation, minutes | 3.6 | 28 | 33 | 2.5 | 15 | 15 | 15 8.2 Reagent type///////// | ECO | ECO Limestone; - / mahbOzMaeboOzmMasoz

Reagent consumption per kg | 32 | 27 | 73 | - | 25 | 25 | 25

Table 1

Processing results and achieved technical and economic indicators during out-of-furnace desulfurization of cast iron according to patent KO 2096484 and according to the invention that is claimed. about, Examples of treatments according to the KO patent Examples of treatments according to

Mo | Technical and economic indicators of the invention 2096484, which p/p and factors are claimed about |Duration of marriage, hv.i | 36 | 28 | 33 | - | 15 | 15 | 15 98 raphaza./////777777777/Ї171111111Ї111171Ї11111Ї11111111g o |Consumption of reagents, kg | 276 | 485 | 273 | 521 | 286 | 460 | 286 o Duration of inhalation, min.d | 7.7 | 126 | 101 | 13.7 | 53.5 | 8.0 | 35 o |Consumption of reagents per kilo, kg | 69 | 139 | 83 | 144 | 229 | 36.8 | 2259 o 7.7 | 126 | 101 | 13.7 | 35 | 8.0 | 35 112 77777777117171111171717171717171173 | 415161 7 | 8 9. With|Typreagent | RK | CC | - | - (| А | А | А o | Consumption of reagents per kg | 48 | 59 | - | - / 304 | 456 | 304 o Duration min.//// | 7701126 | - | - | 35 | 80 | 35 ooo phase ///777777/ Ї7717111Ї111171й11111 11111111 o | Reagent consumption, kg | 68 | 130 | 72 | 76 | 78 | 114 | 122 o | Duration of injection, min. | 1.6 | 22 | 1.9 | 20 | 49 | 71 | 76 10.2 | Reagent type | Sabg | Sa | - | Sam | - | - | - o | Consumption of reagents, kg | 58 | 60 | - | 72 | - | - | - o | Infusion duration, min..d | 1.6 | 22 | - | - | - | - | -

Alumina foam and calcium about |Consumption of reagents, kg | | 77777171 1093 HER 7-17 - | - HER - o |Trivalistb, min.////// | - HER 7 - 11719 HER 1-1 - 1-1

Specific consumption of reagents, subs (Ma 77777771 111003 | 061) 095 | 064 | 030 | 044 | 047 иЙбео 77777777 1717-11 369 1 - | 554 | 15 | 217 | 15 o'clock Yibagye//////777777777771 | 1025 | 0261 - | 032 - | - | - (ZhK 77777777 1 041 1051 - | - 1-1 - 1-1

Yibasi////// 1. | 17115 HER - 1-1 1-11

Yibabb///// 117-117 - 11811 - 17-11 o | Limestone///777/ ІІ 7 - 1031 І - 1 - | - 1-1 o fAluminatkaliciyu.d//-/:/ | 13 HER - 17 - | - 1 - | - 1 - o Ybabyabayed/////// 17111111 oYimaboz///7777777777/ ІІ -1І 7-17 - | 7 - 10851 024 | 0185

FA 77711111 - 11-11 - с1ол2е | ol | Total reagents, kg/t. | 3.76 | 506 | 291 | 450 | 21 | 303 | 2.28 o12|Duration of introduction, min. | 12.9 | 176 | 15935 | 18.2 | 9.9 | 16.6 | 12.6

Temperature decrease in the metallurgical industry 006 i) ve ve v6 ov seveseneinnya 75 kg/t iron " " " " " " from the possibility of 15 | additionally formed, kg/t 3.7 5.0 2.9 4.5 1.8 2.5 21 cast iron sulfur removed, kg/kg (17

Table 1

Processing results and achieved technical and economic indicators during out-of-furnace desulfurization of cast iron according to patent KO 2096484 and according to the invention that is claimed. about, Examples of treatments according to the KO patent Examples of treatments according to

Mo | Technical and economic indicators 2096484 of the invention, which p/p and factors are declared about |ІСshAlchavunuu.u//:/О/ ІІ ІІ 11111111 (Ма 77777771 11090 | 1.83 ) 105 | 192 / 09 | 132 | 141 Yisao 77777777 1717-1041 - | 059 /0165| 024 | 0165

Yibagye///////777777777771 | oil | oil - | o0ol4 1 - | - 11 - (KO 77777771 1 1005 | 0071 - | - 1 - | - 1-1

YiSase////////7 | 0215 | - 1-1 - 1-1

YibSasby/////// 1117-11 7 - 1027| - 1 - | - 1 o |Limestone////777777777 | -1 HER 7 - 10002 | - | - | - | - about fAluminatcalcium.d//-/:/ | 7-0 | - 1 009 | - | - | - | - about YisabzhSage/////// | 023 | - | - | - 1-1 - 1-1 about Yimaboz//77777777 | 77 - Y - 1 - | - 10061007 | 0.06

LA 11111111 - 1117-1717 - 1ole | ol | Oleg

Total for reagents, USD. about (eshatayuuu | moms) yeeeotov te tt

Compensation expenses 18 | temperature loss, USD 0.36 0.49 0.43 0.51 020 | 0.33 | 0.25

US/g of cast iron

Income of Remetg from slag: USD US/g of cast iron " " "

Costs for losses of cast iron with 20 | additional slag, dollars. 0.89 12 0.70 1.8 0.43 0.50

US/g of cast iron

Expenditure on lances, USD

Costs for loading slag 22 | and its disposal, USD 0.7 0.7 0.7 0.7 0.7 0.7 0.7

US/g pig iron pig iron

Prices for reagents: - EK (long flame coal) - 130 dollars. USA; - CaС2о-100 dollars. USA; -SasC5-150 dollars. USA; - CaSoOz3-7 dollars. USA; comparison - bag2-422 dollars USA; - calcium aluminate (tСаоО»пА/12О3з) - 200 dollars. USA; - Ma20Oz-300 dollars. USA; - AI (rod) - 1000 dollars. USA; - Mar - 3000 dollars. USA; - lime powder - USD 110 USA;

The proposed technical solutions according to the claimed invention have been tested in industrial conditions, both individually and comprehensively. The results of treatments carried out according to patent Ky 2096484 (examples are taken from the description of the patent) and according to the method of post-furnace desulfurization of cast iron, which is claimed, as well as the characteristics of their technical and economic indicators are shown in Table 1.

Analysis of the averaged technical and economic indicators of cast iron desulfurization processes according to patent KO 2096484 and according to the claimed invention shows that the claimed method of post-furnace desulfurization of cast iron allows: - to reduce the specific consumption of reagents (on average by 1.51 kg/t of cast iron); - reduce the processing time (on average by 3 minutes); - reduce temperature loss (on average by 9.4 C); - reduce additional slag formation (on average by 2.91 kg/t of cast iron); - reduce losses of pig iron with slag that is additionally formed (on average by 1.90 kg/g of pig iron; USD 0.45); - reduce costs of reagents for removed sulfur (on average by 4.57 kg/kg); - reduce costs for compensation of temperature losses (on average by USD 0.19); - ensure the arrival of pig iron from slag (on average by USD 0.31); - reduce the total cost of desulphurization (on average by USD 0.92); - reduce the specific costs of removing 0.001 95 sulfur (on average by 0.03 dollars

US/tg 0.001 r).

Claims (2)

FORMULA OF THE INVENTION 1. The method of out-of-furnace desulfurization of cast iron, which includes in the first phase of processing the formation of the main ladle slag by introducing into the melt through an immersion nozzle, the corresponding reagents in the flow of the transporting gas, in the second phase of processing desulfurization of the cast iron melt by introducing at least one reagent and introducing the reagent in the third phase processing, which is distinguished by the fact that in the first phase a ladle slag with a basicity of 0.8-1.0 is formed, for which a calcium-containing reagent is blown into the melt to a depth of 0.3-0.5 m by the method of coinjection in a ratio of 3:1-5:1 and a sodium-containing additive and/or an alloy of waste sulfate and sodium carbonate, in the second phase, the sulfur content in cast iron is reduced to 0.030-0.035 wt. 9o, for which calcium- and sodium-containing reagents in the ratio of 20:1-20:1.6 are blown into the melt to a depth of 0.15-0.25 m from the bottom of the ladle by the method of co-injection and aluminum wire is simultaneously introduced, and in the third phase of processing sulfur content in cast iron up to 0.001-0.020 wt. 956, for which a magnesium-containing reagent is blown into the Zo melt by monoinjection, while in the process of the entire processing, protective gas is supplied to the surface of the melt with a flow rate of 20-40 m/h. m3. 2. The method according to claim 1, which differs in that compressed nitrogen, argon or natural gas is used as a shielding gas to adjust the composition of the gas atmosphere.