CA2193539A1 - Procedure to produce a slag conditioner material for electric arc and ladle furnaces based on vermiculite and dolomite mix - Google Patents

Abstract

This invention relates to a procedure for producing a slag conditioner material for electric arc and ladle furnaces, based on vermiculite and dolomite, more particulary, the production of a mixture based on dolomite and vermiculite, as specified in the description, which in adequate proportion, increasing benefits will be achieved in the steelmaking processes in reference to electric energy consumption and heating time. Also, the process fixes the average quantity of dolomite and vermiculite that must be used to obtain the benefits mentioned in an optimum rate, without affecting the life and refractories consumption, yet obtaining an increase in the metallic yield and with lower costs a greater furnace productivity. On the other hand, this invention, is related also to a procedure to develop a practice in which the conditioner material, reazon of the invention, when added to the electric arc an ladle furnaces together with dolomitic lime generates a foamy, saturated MgO slag, wich minimizes chemical erosion, increasing the furnace refractory lining life, with less gunning maintenance.

Description

2 ~ 9 3 5 3 9 BACKGROUND OF THE INVENTION

In recent years, worldwide tendency of iron and steelmaking industry to produce high quality steel with low costs, has shown the importance of good slag practices in primary and secondary steelmaking processes.

There has been a gradual re~li7ation that the slag phase in steelmaking is not a necessary evil, but a crucial part of modern steelmaking practices. Neither the goal to produce high quality steel, nor low costs, can be realized by poor slag practices. That is why the concept "slag optimi7~tion " is becoming more common in many steelmaking works, because of the increasing stringent requirements to obtain steel of higher quality.
This invention relates to a method consisting in adding to the electric-arc furnace or to the ladle furnace, a slag conditioner material, to improve physical and chemical properties; as well as, metallurgical functions of the slag, by totally or partially replacing high calcium lime and/or dolomitic lime, traditionally used to form slag in the steelmaking processes.

More generally, the invention provides a practice to generate a foamy slag with a high sulfide capacity, compatible with the furnace refractories, which permits to obtain a high quality steel; with less electric energy consumption, less heating time, less consumption of refractory materials for the furnace repair maintenance, longer life of the furnace 2 1 93~39 2 -refractory lining, higher metallic yield and greater furnace productivity, with a considerable reduction in steelmaking costs.

An important feature of this invention is due to the slag conditioner material, is a mixture of minerals of dolomite and/or limestone, specifically with the mineral vermiculite andlor minerals of the group of the vermiculite like montmorillonite, chlorite, biotite and mica.
Verrniculite is an hydrated silicate containing varying amounts of iron, magnesium oxide, alumina and potassium. Vermiculite has the property of being highly resistant to heat, for which it is used as an insulating refractory material. Another important property of vermiculite is that when heated at temperatures between 870 and l 100~C it expands 12 to 20 times its original volume.

This two properties of vermiculite are decisive for the use of this material mixed with dolomite and/or limestone, reason of this invention, to obtain improvements in the steelmaking process previously mentioned and further analyzed.

In this invention perlite mineral may be used instead of vermiculite, which has similar insulating properties and it also expands its original volume lO to 20 times when heated at temperatures between 760 and l 100~C, however, as in its chemical composition the silica content is very high and it only contains traces of magnesium oxide, its application is limited, preferring for this reason the use of vermiculite.

High calcium lime traditionally used worldwide to form slag, comes from the calcination of calcium carbonate (CaCO3), which is found in the form of minerais as calcite and aragonite. Impure calcite occurs in limestone rock in high quantities in most parts of the world. Limestone may vary from pure calcium carbonate to pure dolomite CaMg(CO3)2.

Dolomitic lime, which comes from the calcination of dolomite, began to be used at industriai level in the steelm~king processes starting from the 60 s, mainly due to the beneficial effects of the magnesium oxide, which reduces the slag chemical erosion of the furnace refractory lining.
Comercial limes are classified according to their relative content of CaO
and MgO as follo-vs:
Lime of high CaO content Less of ~ % magnesium oxide magnesite lime 5 to 25 % magnesium oxide Dolomitic lime 25 to 45 % magnesium oxide A great disadvantage of both types of lime is its g~eat tendency to absorb moisture and carbon dioxide from the atmosphere, generating fines, the fines quantity depends on the storage conditions and the time of storage. No advantage of is taken from the fines generated, because one part of them is eliminated during its handling in the way to the furnace and the rest is carried away by the gas extraction system installed in the furnace for environmental control, this causes considerable increases in lime consumption that impacts steelmaking costs.
One advantage of the slag conditioner material, reason of this invention, is that as it is a material which has not been calcined it is not _ 2 1 93539 4 degradable and therefore, neither special installations for its storage, nor special cares for its handling are required, and it can be stored indefinitely without causing deterioration to its composition, even if it is stored out of doors, achieving l 00 % of its use.

The main functions of the slag in the steelm~king process include the following:
- Insulate the metallic bath, maintaining the steel temperature.

- Stabilize the electric-arc to protect the refractories ~om arc flare damage.

- Be compatible with the refractory material to minimi7:e chemical erosion of the lining.
- Improve the quaIity of the steel by absorbing sulfur and phosphorus.

- Protect steel from oxidation and help to control steel chemistry.

- Flux and trap inclusions from the steel.

Slag are ionic solutions consisting of molten metal oxides. The composition of the slag is usually expressed in terms of the component oxides on a weight percent basis, of which the principal are sio2, CaO, MgO, Al2O3 FeO, MnO and Cr2O, A number of formulations have been used to express a slag s 2 ~ 9 3539 5 basicity. The most common approach is to use a basicity iIldex in which basic oxides are placed on the numerator and acid oxides on the denominator. Of these, the most commonly used is the V ratio (%CaO/%SiO2), know as binary basicity. Other formulations are also used, asthetertiary basicity %CaO + %M~O
% sio2 and the quaternary basicity %CaO + %M~O
%SiO2 + %Al~03 Recently, a more fundamental indicator of slag basicity, namely optical basicity, has been established, which actually is the best compositional parameter available that can be used to describe a slag s composition. However, neither one of these parameters does not say anything about the physical properties of a slag.
An optimum slag can be defined as a slag that fully compatible with the refractories and maximizes the quality of the steel. A good slag has sufficient fluidity at steelm~king temperatures to optimize slag-metal interactions, but it is not too fluid to attack the refractories. Generally thisslags have a creamy consistency. A slag consists of two portions: a liquid fraction and a solid fraction ( one or more crystalline phases ). The solid fraction of the sla~ can be undissol~ed fluxes or primary crystalline phases.
The viscosity of an all liquid slag is determined by the temperature and the composition of the slag. In general, the viscosity of an all-liquid slag gradually increases as the silica content of the slag increases. However, a factor ignored by many, that has a much more pronounced impact on slag viscosity, is the solid fraction of the slag. A specific slag has maximum 2 ~ 93539 6 fluidity when it is completely liquid. As the solid fraction of the slag increases, its viscosity increases exponentially.

An optimum slag must be saturated with calcium oxide (CaO) and magnesium oxide (MgO) and must have high fluidity to maximize slag-metal interactions. This slag is totally compatible wiht both magnesite and dolomite refractories. MgO solubility in slag is minimum when slag is also saturated with CaO. However, if slag is not saturated with CaO, MgO
solubility in the slag increases considerably. If additional MgO is not added to this slags, it will dissolve MgO from the refractory.

In the electric-arc furnace energy is trasmitted from the end of the electrodes to the metallic batll through the slag, which is a good heat transfer. Previous studies estimate that in the case of the electric-arc approximately 85 % of the electric power is dissipated by radiation to the walls and furnace roof, originating hot spots and damage to the refractory, and only 14 % of the energy is transmitted from the end ofthe electrodes to the metallic bath and is transformed into heat.

~rom recent years a new practice has been used, consisting in the formation of a foamy slag which keeps the electric-arc cover in, improving heat transfer from arc to bath for faster temperature pickup of the metallic bath.

When a foamy slag practice is employed most of the arc radiation is absorbed, resultin~ in improved heat transfer and the heat load on the furnace side walls and roof is greatly reduced.

21935~9 7 A conventional slag practice using high calcium lime, dolomitic lime andlor a mixture of both, lead to a high lost of arc radiation and damage on side walls and roof furnace refractories; for this reason it is necessary to promote the formation of a foamy slag, practice which consists in carbon injection over the bath, either on top of the slag (through the roof), or into the same slag (through the furnace's-door), the reduction of the oxides contained in the slag by the injected carbon form a gas (Co & Co2). The gas is trapped in the slag causing it to foam up, the foamy slag cover in the electric-arc improving its efficiency by absorbing arc radiation, resulting in improved heat transfer (decrease of the electric energy consumption and/or increase of the heating velocity ). The foamy slag shield~ the side walls from arc radiation reducing refractories damage.

The main purpose of this invention is to use the advantages of operating with a foamy slag, which actually is achieved injecting carbon, practice wich requires additional equipment installations for its handling and an additional increase in the cost of steel production by the carbon used. On the other hand, with the slag conditioner material, reason of the invention, the verrniculite properties are taken advantage of: The first, when the vermiculite is heated, it expands its original volume 12 to 20 times, this helps the slag to foam up, reducing the radiation losses and protecting the refractories above the slag line.

The second, because the high heat resistant property of the vermiculite, it promotes the formation of an opaque and insulating slag, which greatly reduces the slag emissivity, resulting in a heat transfer improvement from arc to bath, faster heating velocity and increasing tons.
per hour.

This two important properties of the vermiculite helps to form a foamy and highly insulating slag, estimating that the heat transfer efficiency from the arc to the metallic bath increases from 35 % with the conventional slag to 93 % when the electric-arc is totally cover by the slag.

Besides of using the advantages represented by the vermiculite and/or minerals with similar properties, the slag conditioner material reason of this invention, is an uncalcined mixture of said minerals with doIomite and/or limestone; which, when heated at a temperature between 700 and 1100~C, they are decomposed into magnesium oxide, calcium oxide and CO2. When the slag conditioner material is supplied to the electric arc furnace in which the operating temperature is superior to that required to decompose the carbonates, a determined quantity of CO2 is driven off as gas, depending on the quantity of dolomite and/or limestone used in the mixture, which also helps to foam up the slag.
Nowadays, most of the steel producers worldwide use in their electric-arc fi~rnaces and ladle furnaces, basic refractory lining of magnesite and dolomite and in the steelmaking processes, high calcium lime, dolomitic lime or a mixture of both to form slag. A great disadvantage of high calcium lime, is its low content of magnesium oxide. The slag formed with this type of lime, will not protect the furnace slag line and bottom refractories from chemical erosion . The only natural 21 q353~ 9 -source of magnesium oxide in the furnace is the refractory lining. The slag extracts the magnesium oxide needed to maintain chemical equilibrium from the furnace lining. With this type of chemical erosion will result in an increase of gunning maintenance, heating time, shortest lining life, increasing overall operation costs and less productivity.

To supply the magnesium oxide required by the slag, dolomitic lime is used, so the slag no longer has to extract the magnesium oxide from the furnace refractories to satisfy its chemicai needs. ~inimi7ing in this way the chemical erosion, will result in less gunning maintenance, increased refractory life and greater furnace productivity. However, the use of this material is limited, especially in the melting shops using 100 % scrap, because when the MgO content of the slag is high, its viscosity increases due to the formation of magnesium ferrites, which have melting points ( 1730~ C) superior to the operating temperatures of an electric-arc furnace, generating a high viscosity slag which difficults furnace operation, affecting the metallurgic properties of the slag to remove sulphur and phosphorus. Consequently, to produce steel with the required specification, the slag high in sulfur and phosphorus, has to be skimed and a new slag has to be made up with the addition of more fluxes. This is usually an expensive option, because besides increasing the melting time, some metal is lost during deslagging, requiring the use of more quantity of lime, increasing refractory chemical erosion. To prevent the problems promoted with a high viscosity slag when using 100 % dolomitic lime, most of the steelmaking producers use as a practice both types of lime, with furnace additions of varying amounts, either separated or mixed.

2 1 9353q 10 Another fundamental purpose of this invention, is based in a practice especifically developed to form at the earliest stage of the heat a fluid and foamy slag, whith a creamy consistency and magnesium oxide saturated, which improves slag-metal interacions and the potencial ability of the slag to remove sulfur and phosphorus, producing a steel of high quality. The magnesium oxide saturated slag is fully compatible with the furnace lining refractory, minimi~ing chemical erosion and increasing refractory life.

The pure individual components oxides of the slag, sio2~ CaO, MgO, Al2O3, FeO, etc. melt at very high temperatures, from the above, it is required that extensive fluxing between the components oxides, had to ocurr at steelmaking temperatures in order to form liquid slags. The extent of fluxing between the various oxides is usually shown graphically on phase diagrams, which are a very useful tool to determine the optimum slag compositions.

Pure oxides melt at specific temperatures, for instance, pure MgO, totally solid at 2799~C will be totally liquid at 2800~C. However, when we add another component to MgO, fluxing ( lowering of the melting temperature ) of the MgO will ocurr. The amount of fluxing will depend on the type of component added. - -The binary phase diagrams of the system CaO-SiO~ and MgO-SiO2 show that silica is a potent flux for CaO and MgO, to form 2~ CaO-SiO2 or MgO-SiO2 slags at steelmaking temperatures. In order to evaluate the fluxing effect of SiO2 on CaO and MgO together, an equilateral triangle with the three components on the corners of the ~.
triangle is usually drawn. A map of the phase relations as a function of temperature and composition for any mixture inside this triangle, under equilibrium conditions, is plotted in the phase diagram as shown in figure 4, most steelmaking operations are conducted around 1600~C, so that this diagram can be greatly simplified if the phase relations is examined only at this temperature.

This simplified diagram contain three different areas, depending on the composition of the mixture CaO-MgO-SiO2. An area with a low sio2 content, high CaO and MgO content, indicating that this slag will be completely solid, an area with a sio2 slag content between 44 to 67 % indicating that this slag is completely liquid and an area with a slag consisting of liquid and solid phases. The amount of liquid will depend on the amount of SiO2 in the slag.
As previously mentioned, a totally liquid slag which is not compatible with the refractory, is chemically very aggressive, accelerating the deterioration of the refractory lining life and with a totally solid slag itis impossible to work. Thus, a great ad~antage of this invention is to provide a material in order to obtain the optimum desired foamy slag, with the required fluidity to optimize siag-metal interactions, ~vhich is compatible with the furnace refractory lining and with a creamy consistency. For this reason, due to the fluxing effect of silica, which increases the amount of liquid phases in the slag at the steelm~king operating temperatures and by the fact that the slag becomes saturated with magnesium oxide by the magnesia contained in the dolomite; as well as the CO2 driven off from the dolomite when heated at steelmaking -temperatures, promoting the formation of a foamy slag. The material reason for this invention, has as main components an average of 28 %
CaO, 17%MgO, 12%SiO2and40%CO2.

From the above, another purpose of this invention is to develop a practice in which, when replacing the high calcium lime by the slag conditioner material, combined with dolomitic lime, promotes the formation of a totally magnesium oxide saturated slag, which minimi7es it's chemical erosion, resulting in less gunning maintenance, increased refractory life and greater furnace productivity. This materials can be added to the furnace intermittently or continuously during the heat, separated or previously mixed. Practical trials have shown that the best results have been obtained using 40 % dolomitic lime and 60 % of the conditioner material reason of this invention. The slag conditioner material can also be used 100 % to form the slag in the steelm~king processes.

One of the most important functions of the slag is its sulfide capacity and improve the steel quality . The term sulfide capacity (Cs) is used to describe the potential ability of a completely liquid slag to remove sulfur.
The fact that a slag might have a favorable Cs value is no guarentee that good steel desulfurization will occur. It only means that slags has the potential to remove sulfur from the steel. Other factors that have a profound impact on the extent of the sulfur actually removed from the steel are:
. Oxygen content of the steel.
Oxidation state of the slag.
The extent of mixing between the steel and the slag.

21 ~3539 13 Viscosity of the slag.
. The amount of slag.
. Temperature.

One of the most important aspects that is frecuently overlooked when evaluating and discussing slags, is that most slags consist of two fractiones, i.e., a liquid fraction and a solid fraction. Slag fluidity in basic slags is controlled by the liquid and solid fractions of the slag. The higher the solid f~action of the slag the lower the fluidity of the slag (greater viscosity). A basic slag which is completely liquid, has maximum fluidity.

The following example ilustrates the importance of fluidity and effective slag volume.
Consider the following two slags at 1 600~C
Slag 0 (figure 10 ) Slag K (figure 5 ) %SiO2 3~ 35 %CaO ~ 45 50 %MgO 17 15 Phases present100 % Liquid 43 % liquid, 45 % Ca~SiO4 2~
(optimum slag ) 12 % MgO

2 1 9 ~ 5 3 9 14 _ In many calculations of sulfur removal, the total composition of the slag is sometimes mistakenly considered. It is the lime disolved in the liquid fraction of the slag that is removing sulfur from the steel and not lime as determined by the chemical analysis of the total slag. The undissolved lime in the slag does not remove any sulIur. The liquid fraction of the slag K has an identical composition as slag O. Thus, only 43 % of the slag K has the sulfide capacity in relation to slag O. The addition of more lime then required, only resulted in a decrease inthe amount of liquid that can desulfurize and an increase in the viscosity of the slag. In steel the sulfur distribution ratio is defined as: Cr=( % S ) where [%S}
(% S) is the sulfur content of the slag, and L% S} is the sulfur content of the metal. From the above definition it is obvious that higher Cr values are desired for good sulfur removal.
One of the factors with a profound impact in the sulfur distribution rate is the oxygen content of the steel. If the temperature and slag composition is fixed, the effect of the steel oxygen content in the sulfur distribution rate is highly significant, for example: for a steel with an oxygen content of 50 p.p.m., the sulfur distribution rate is 123 and for a steel with an oxygen content of 10 p.p.m., the sulfur distribution rate increases considerably to 613; A significant increase in the sulfur distribution rate is observed, when the oxygen content of the steel decreases from 50 to l0 p.p.m. This increase in the sul~ur distribution ratio indicates that a higher deoxidized slag has a greater sulfide capacity.
A fully reduced slag with a good desulfurizing capacity and a steel with a low oxygen content will result in a high sulfur distribution ratio, which is required for good sulfur removal. However, this is still no guarantee that efficient sul~ur remGval will actually occur in practice.
Extensive intimate mixing between the slag and the steel is required to overcome the kinetic barriers. Therfore a sufficiently fluid slag is required to ensure sulfur removal.

Nowadays most of the steelm~king producers believe that a slag with a high bina~7 basicity is required to achieve a good sul~r removal.
Sulfur is elimin~ted in the form of calcium sulfide CaS and for that reason, they use large qu~ntities of CaO to ensure sulfur removal. The fact is that the binary basicity CaO/SiO2 has not much influence over the sulfide capacity of a slag, and this depends mainly on the state of oxidation and fluidity of the slag, at the steelmaking temperatures. It has been found in practice, slags with low oxidation and binary basicity less than 1.5/1, with sulfur contents of 0.60 % and slags with high oxidation and binary basicity greater than 2.5/1, with sulfur contents of only 0.030 %, 20 times Iess sulfur distribution ratio; if the ratio CaO/SiO2 is greater than 2/1, the whole, or at least part of the iron oxides contained in the slag, combines with the CaO whith the formation of calcium Ferrites CaO.Fe2O3. Some of which have lower fusion temperatures ( 1270~C), which appear to be one ofthe principal causes of wear in basic refractories. On the other hand,-if the ratio is less than 2/1, all of the Fe2O3 reacts with MgO to form spinels MgO.Fe2O3, which have higher fusion temperatures (1730~C), superior at the steelmaking temperatures; this is the reazon why, when adding a greater proportion dolomitic lime/high calcium lime, the slag increases its content of magnesium oxide, increasing it's viscosity. However, to obtain an optimum slag with a high sulfide capacity, it is required a binary basicity lower than 2/1 to force the formation of magnesium ferrites and be able to have free CaO in the slag~
that can combine with the sulfur contained in the steel, removing this sulfur as CaS through the slag. It is quiet clear, that the slag MgO content increases with the addition of dolomitic lime, resulting in an increase of the Terciary basicity %CaO + %M O . Practical trials % SiO2 have also shown that the greater the tertiary basicity, the greater the sulfur distribution ratio.
The importance of the practice in agreement with this invention, is because totally replacing the addition of high calcium lime, with low magnesium oxide content, to the electric arc furnace by the slag conditioner material and whit also the addition of dolomitic lime, a slag with a terciary basicity of minimum 2.5 is achieved, which is compatible with the furnace lining refractory, minimi~ing considerably the chemical erosion and with a high fluidity to m~scimi7e sulfide capacity.

Another purpose of this invention which is of special importance, is due to the fact that with partially or totally replacement of the high calcium lime and dolomitic lime by the slag conditioner material, a lower quantity of slag is generated, and whith a final FeO slag content remaining constant, the iron losses are reduced and a higher metal yield is attainable.
In a chemical analysis the CO2 content of the lime is reported as lost of ignition (L.O.I.). When a lime is totally calcined its CO2 content is 0 - 2 1 93s3q %. A good calcined lime has a maximum of 2% lost of ignition.
Commercial limes normally used in the steelm~king industry have around 5 % lost of igni~ion, when this lost of ignition is superior than 5 %, it is a lowquality semicalcined lime. The slag conditioner material's lost of ignition is about40%.

When commercial lime which is normally used in the steelm~king industry is added to the furnace at the steelm~king temperatures, 95 % of its components will form slag and the rest 5 % is driven off as gas CO2. On the otherhand, when adding the slag conditioner material to the furnace at the steelm~king temperatures, 60 % of its components form slag and 40 % are driven off as gas CO2. When replacing one ton of high calcium lime or dolomitic lime by one ton of the slag conditioner material, ther~ will be 350 Kg (36.8 %) less quantity of slag former materials. The difference in the quantity of slag formed between the traditional practice using high calcium and dolomitic lime and the practice reason of this invention, will depend on the quantity of lime replaced by the slag conditioner material. With the proposed practice reason of this invention, in a el-ectric arc furnace using 100 % scrap, 40 % dolomitic lime and 60 % the slag conditioner material, about 15 % less quantity of slag will be generated.

Finally, annother object of the invention, is to develop a practice adding the slag conditioner material, together with dolomitic lime, in order to obtain a basic slag compatible with the furnace linining refractory, resulting in the following benefits:

_ 2 1 93539 ~ Reduction in electric energy consumption andlor increasing the heating velocity.

~ Minimi7e siag line and bottom chemical erosion.

~ Reduction of refractory maintenance between heats.

~ Reduction of time ang gunning meterials.
~ Increase of furnace lining life.

~ Grater furnace productivity.

~ Reductionoffurnace operationcosts.

Results obtained of trials carried out with the practice 60 % of the conditioner material and 40 % dolomitic lime, show that it has been achieved a reduction of as much as: l l % electric energy consumption, l 1 minutes less heating time per heat, 60 % less gunning, refractory materials, and an increase of as much as: 30 % furnace refractory lining life, 2.5 % the metallic yield and a furnace productivity increase of lS
tons./hr.

DESCRIPTION OF THE INVENTION

The raw materials quarry of both dolomite and vermiculite are opencast working by the use of explosives; subsequently, the raw materials are crushed using jaw crushers, roll crushers or any other automatically or manual crushing sistem. when this is achieved, the resulting crushed products passed through a vibrating screening system to select the size of 3/8" to 0" that will be used for the mixture of both materials.

Once screened, each one of the mixture components ( dolomite and vermiculite ) are transported whit belt conveyors to a diferent separate hoopers, each of these hoopers discharge into weighing cars the proportional quantity needed of both materials ( 75 % dolomite and 25 % vermiculite ).
Once the ~veight is accomplished, the weighing cars feed their content into a helicoidal mixer, by means of which the mixture is homogenized with the proportions previously mentioned, and afterwards, the mixed material is conveyed to the storage hoppers ready for shipment.

Claims (3)

CLAIM
The embodiments of the invention, in which an exclusive property or privilege is claimed, are defined as follows:

1.- Procedure to produce a slag conditioner material for electric arc and ladle furnaces based on vermiculite and dolomite mix, in which both raw materials of quarry dolomite and vermiculite are obtained through opencast working by the use of explosives; subsequently, the raw materials are crushed using jaw crushers, roll crushers or any other automatically or manual crushing sistem. when this is achieved, the resulting crushed products passed through a vibrating screening system to select the size of 3/8" to 0" that will be used for the mixture of both materials.

2.- Procedure to produce a slag conditioner material for electric arc and ladle furnaces based on vermiculite and dolomite mix as described in claim 1, in which once screened, each one of the mixture components (dolomite and vermiculite) are transported whit belt conveyors to a diferent separate hoopers, each of these hoopers discharge into weighing cars the proportional quantity needed of both materials (75% dolomite and 25% vermiculite).

3.- Procedure to produce a slag conditioner material for electric arc and ladle furnaces based on vermiculite and dolomite mix, as described in claim 1, in which once the weight is accomplished, the weighing cars feed their content into a helicoidal mixer, by means of which the mixture is homogenized with the proportions previously mentioned, and afterwards, the mixed material is conveyed to the storage hoppers ready for shipment.