ES2373268T3 - TREATMENT SPOON. - Google Patents

Abstract

A treatment ladle comprising a ladle shell containing a generally tubular refractory ladle liner, said ladle being pivotable between a horizontal position and a vertical position, said ladle liner having a first end and a second end with a continuous sidewall therebetween, an interior space being defined between said first and second ends and the continuous sidewall, said ladle liner additionally comprising a pocket for holding a treatment agent, said pocket being located adjacent the first end and in fluid communication with the interior space and located closer to the top than the bottom of the interior space when the ladle is in its horizontal position and closer to the bottom than the top of the interior space when the ladle is in its vertical position, and a spout for receiving and pouring molten metal located closer to the top than the bottom of the interior space when the ladle is in its horizontal and vertical positions, wherein in the horizontal position, a lower volume of the interior space defined below a plane midway between the top and bottom of the interior space and between the first end and a vertical plane intermediate the first and second ends is greater than an upper volume of the interior space defined above the midway plane and between the first end and said vertical plane. The treatment ladle is designed for the treatment of molten metal with vaporisable additives, in particular in the preparation of ductile iron. The invention also relates to a method of treating molten metal employing the ladle.

Description

Treatment spoon

The present invention relates to a spoon for the treatment of molten metal with vaporizable additives, in particular, to a spoon for the treatment of iron with magnesium (Mg) to form ductile iron.

Ductile iron, also known as spheroidal graphite iron or nodular iron, is manufactured by treating liquid iron with a so-called nodularizer (or nodulizer) before casting. The nodularizer favors the precipitation of graphite in the form of individual nodules. In practice, the nodularizer usually contains magnesium, in the form of pure magnesium, or in the form of an alloy, such as magnesium-ferrosilicon (MgFeSi alloy)

or nickel-magnesium (NiMg alloy), which may contain rare earth metals. In a typical procedure, magnesium is added to the liquid iron to provide a residual magnesium content of approximately 0.04%, the iron is inoculated and cast. It is difficult to add magnesium to iron since magnesium boils at a relatively low temperature (1090 oC) so that violent agitation of liquid iron and considerable loss of magnesium in the form of steam occurs.

Several procedures have been developed to prepare ductile iron, which include:

The sandwich spoon - the treatment alloy is present in a recess in the lower part of the spoon and is covered with steel scrap. The spoon can be covered, for example, with a refractory trough cover. The iron is then poured into the spoon and the reaction with the treatment alloy is slowed down by means of the steel scrap barrier. This procedure is simple and widely used, although Mg recovery rates are not constant. In addition, it is necessary to use more nodularizer to satisfactorily achieve the desired level of treatment. Piston - the treatment alloy is immersed in the bucket using a refractory piston bell. This procedure is only practical for large quantities of metal. Converter - the nodularizer is placed in a hole at the base of the cylindrical bucket. The spoon is filled with liquid iron while it is in horizontal orientation, sealed and rotated to the vertical position so that the magnesium is submerged under the iron. Core wire treatment - the wire containing nodularizer (for example MgFeSi alloy) inside the iron is fed mechanically using a station built for this purpose. Treatment inside the mold - the nodularizer (for example FeMgSi alloy) is placed in a molded chamber inside the operating system so that the iron is treated continuously as it flows over the alloy.

An object of the present invention is to provide a spoon for the treatment of metal with vaporizable additives.

Another object of the present invention is to provide a process for the treatment of a molten metal with vaporizable additives.

According to a first aspect of the present invention, a treatment spoon is provided comprising a spoon cover containing a generally tubular and refractory spoon liner, said spoon being able to pivot between a horizontal position and a vertical position,

said spoon covering having a first end and a second end with a continuous side wall between them, a defined interior space being left between said first and second ends and the continuous side wall,

said spoon covering additionally comprising a cavity for housing a treatment agent, said cavity being located adjacent to the first end and in fluid communication with the interior space and located closer to the upper part than to the lower part of the space inside when the spoon is in its horizontal position and closer to the bottom than the top of the interior space when the spoon is in its vertical position, and a casting channel to receive and pour the molten metal located nearest to the top than to the bottom of the interior space when the spoon is in its horizontal and vertical positions,

in which in horizontal position, the lower volume of the interior space below the plane halfway between the top and the bottom of the interior space and between the first end and an intermediate vertical plane between the first and second ends is greater that the upper volume of the interior space defined above the plane halfway between the first end and said vertical plane.

From the foregoing, it should be understood that in the vertical position, the first end of the spoon lining constitutes the lower point of the interior space.

During use, the treatment agent is placed in the cavity and the spoon is filled with molten metal while

which is in horizontal position. In general, the spoon is half full so that the molten metal is filled to a height that corresponds to the plane halfway. Subsequently, the spoon is pivoted 90o to the vertical position so that the metal flows into the cavity containing the treatment agent. The treatment agent is vaporized after contact with the molten metal and bubbled through the metal head above the cavity. Subsequently, the spoon is pivoted again in order to distribute the treated molten metal through the casting channel. In a particular embodiment, the bucket is pivoted more than 90 ° from the horizontal position, through the vertical position, to a third position in which the treated molten metal is dispensed (dispensing position).

The spoon of the present invention is useful as it minimizes the surface area of metal that is exposed to the air when the spoon is in a horizontal position. The reduction of the surface area is associated with the reduction of heat loss of the metal. If heat loss is reduced, the metal can be poured inside the bucket at a lower temperature, thereby reducing wear on the refractory lining and other foundry devices. A lower temperature when pouring inside the spoon also favors a smaller expansion of magnesium vapor, which reduces the violence of the reaction (between magnesium and hot metal). It is thought that this improves the recovery of magnesium, since more magnesium vapor is effectively maintained inside the liquid iron, and the temperature loss after treatment is reduced since less reaction violence means that there is less metal contact with the coldest atmosphere.

Another advantage of the spoon of the present invention is that it maximizes the metal head that is above the treatment agent when the spoon is in an upright position. A larger metal head is associated with a reduction in the violence of the reaction between the metal and the treatment agent and, in the case of a treatment agent containing magnesium, a better and more constant recovery of magnesium.

It should be understood that the advantages of the present invention are obtained due to the shape of the spoon lining, in particular the shape of the parts of the spoon lining that are in contact with the molten metal when the spoon is filled (position horizontal) and when the molten metal is being treated (vertical position). A vertical plane (intermediate between the first and second ends of the liner is chosen when the spoon is in its horizontal position) in order to evaluate the shape of the spoon liner. The vertical plane should be chosen to represent the typical cross-section of the bucket liner. When the spoon lining has a regular shape so that the cross section of the continuous side wall is constant along its length, the vertical plane can be chosen at any point between the first and second ends. Conveniently, the vertical plane can be equidistant between the first and second ends of the liner when the bucket is in its horizontal position.

In a particular embodiment, the cavity extends from the first end of the spoon liner outwardly from the interior space (that is, it extends below the first end when the spoon is in its vertical position). This provides an additional increase in the metal head over the treatment agent when the spoon is in the vertical position since the molten metal can fill the cavity. As mentioned earlier, a larger metal head is associated with a reduction in the reaction violence between the metal and the treatment agent and, in the case of a magnesium-containing treatment agent, a greater magnesium recovery and more constant In an embodiment in which the cavity extends from the first end, the length of the cavity may be 50 to 1200 mm, 200 to 1000 mm or 400 to 600 mm.

In an alternative embodiment, the cavity is located within the interior space. In any case, the cavity must be in fluid communication with the interior space or be able to be in fluid communication with the interior after coming into contact with the metal. For example, the cavity may be defined by a mesh or lattice having openings small enough to retain the treatment agent while allowing molten metal to pass through it, or it may be made of a material that is melted (such as a metal) thus providing access to the contents of the cavity. It should be understood that generally the volume of the cavity can be small with respect to the volume of the interior space. The shape of the cavity is not particularly limited but, conveniently, the cavity is enlarged in order to ensure retention of the treatment agent. It can have a circular or triangular cross section.

The ratio of the lower volume to the higher volume may be at least 1.5: 1, at least 2: 1 or at least 3: 1.

The height of the interior space (the distance between the top and bottom of the interior space, as defined by the interior of the continuous side wall), when the bucket is in its horizontal position, can be 220 mm 1500 mm, from 400 mm to 1000 mm, or from 600 mm to 800 mm.

The height of the interior space (the distance between the top and the bottom of the interior space), when the bucket is in its vertical position, can be 400 mm to 3000 mm, 800 mm to 2000 mm or 1000 mm at 1500 mm

The proportion of the atura of the interior space, when the spoon is in its vertical position, with respect to

The height of the interior space, when the spoon is in its horizontal position, can be at least 1: 1, at least 2: 1, at least 3: 1 or at least 5: 1. The proportion of the height of the interior space, when the spoon is in its vertical position, with respect to the height of the interior space, when the spoon is in its horizontal position, can be no more than 6: 1, no more than 4: 1 or not more than 3: 1.

In an embodiment in which the cavity extends from the first end outwardly of the interior space, the proportion of the height of the interior space, when the spoon is in its vertical position, with respect to the length of the cavity can be of at least 1.5: 1, at least 2: 1, at least 2.5: 1 or at least 3: 1.

The side wall has an inner surface and an outer surface that can have the same or different shapes. Conveniently, the side wall has a uniform thickness such that the inner and outer surfaces have the same shape. It should be understood that it is the inner surface of the continuous side wall that defines the shape of the inner space and therefore, references to the cross section of the continuous side wall refer to the cross section of the inner surface of the continuous side wall.

The continuous side wall may be defined by three or more wall parts so that the cross section of the continuous side wall is considerably polygonal. In an embodiment in which the continuous side wall is defined by three wall parts, the cross section of the continuous side wall is considerably triangular. In an embodiment in which the continuous side wall is defined by three or more wall portions of equal length, the cross section of the continuous side wall is in the form of an equilateral triangle. In any of the embodiments in which the cross-section is based on a polygon, the corners may be rounded and / or the sides may be curved outward. Conveniently, the cross section of the side wall can be measured in the intermediate vertical plane between the first and second ends.

In an embodiment in which the continuous side wall is defined by three sides of the side wall, said cross section of the continuous side wall is considerably triangular, the proportion of the height of the interior space being able to be, when the spoon is in position. vertical, with respect to the height of the side wall part of at least 1: 1, at least 1.5: 1 or at least 2: 1.

In an embodiment in which the side wall is defined by three sides of the side wall, said cross section of the continuous side wall is considerably triangular, the triangular cross section defines an inscribed circle, that is, the largest circle that can remain contained inside the triangle. In such a case, the proportion of the height of the interior space, when the spoon is in its vertical position, with respect to the radius of the circle inscribed by the triangular cross-section can be at least 1.5: 1, at least 2: 1 or at least 3: 1.

The spoon comprises a casting channel to initially receive and subsequently distribute the molten metal after treatment. This is particularly beneficial since it allows the metal to be poured directly from the spoon into the casting molds, without the need for reuse operations of the spoon. This has the double benefit of reducing temperature loss and improving laundry productivity by eliminating a stage in the laundry process.

Suitable refractory materials include those described for example in EP 0675862B1 and in particular KALTEK (RTM) which is a refractory lining made of silica, alumina and magnesite that is bonded by means of an organic material such as a phenolic resin. In a particular embodiment, the continuous side wall is of unitary construction.

The bucket can be mounted on a crane or forklift or other machinery in order to swing the bucket.

The spoon cover can be a conventional cylindrical cover or a solidified cover adapted to the shape of the spoon lining. If a conventional cylindrical cover is used, it is necessary that the inner and outer surfaces of the continuous side wall have different shapes, that is, that the refractory lining does not have a uniform thickness. If a non-cylindrical cover is used, the inner and outer surfaces of the continuous side wall may have the same shape. For example, when the lining of the spoon comprises a side wall having a triangular cross-section, the cover can also have a triangular cross-section, that is, it can have a triangular prism shape.

In a particular embodiment, the spoon cover and the spoon coating have considerably the same shape. This has the advantage that a minimum amount of refractory material can be used. Alternatively, the spoon may comprise a conventional cylindrical spoon cover. This may be appropriate when a conventional cylindrical cover is reused. The efficiencies of the spoon lining would compensate, at least partially, for the cost of the additional refractory material needed to fit the spoon liner inside the cover.

In accordance with a second aspect of the present invention, there is provided a process for the treatment of a molten metal comprising

loading the spoon of the first aspect by placing a treatment agent in the cavity,

fill the spoon while it is in its horizontal position to a level below the cavity with molten metal,

and pivoting the spoon from its vertical position so that molten metal flows over the treatment agent inside the cavity.

In a particular embodiment, the method comprises swinging the spoon more than 90 ° from the horizontal position, through the vertical position to a distribution position in which the molten metal is distributed through the casting channel after the treatment. In another embodiment, the method comprises pivoting the spoon approximately 180 ° from the horizontal position, through the vertical position, to the distribution position in which the treated metal is distributed.

In a particular embodiment, the spoon is filled to a level corresponding to the plane halfway between the top and bottom of the interior space when the spoon is in a horizontal position.

The process of the present invention is particularly suitable for the preparation of sweet iron, in case the treatment agent is a nodularizer and the molten metal is iron.

In one embodiment, the treatment agent is a nodularizer containing magnesium. Appropriate nodularizers include pure magnesium, ferrosilicon and magnesium alloy (MgFeSi alloy), nickel magnesium alloy and magnesium-iron briquettes.

The spoon and the process of the present invention can be used for the production of both ductile iron (spheroidal graphite) and vermicular iron (compacted graphite).

The process may comprise inoculation of molten metal after the reaction with the treatment agent (for example, the nodularizer). Inoculants are alloys added in small quantities to induce the eutectic nucleation of graphite. Appropriate inoculants include those based on ferrosilicon and calcium silicide.

The process may comprise the preparation of the molten metal before the reaction with the treatment agent. It is thought that the preparation agent prevents the oxygen activity of the molten metal so that the subsequent treatment is more satisfactory. Appropriate preparation agents include those described in WO 2008/012492.

Embodiments of the invention are described below by way of example only with reference to the accompanying drawings in which:

Figure 1A is a perspective view of a spoon according to an embodiment of the invention. Figure 1B is a perspective view and Figure 1C is a cross-section of the spoon shown in Figure 1A during assembly. Figure 1D and 1E are cross-sections of bucket assembly forming devices that It is shown in Figure 1A. Figure 1F is a cross-section of the spoon shown in Figure 1A. Figure 2A and 2B are schematic drawings of the spoon shown in Figure 1A. Figure 3A and 3C show a spoon according to an embodiment of the invention. Figure 4A and 4B show a conventional spoon by way of comparison. Figure 5A through 5D show simulations using MAGMASOFT (RTM) software.

Figure 1A shows a spoon 10 according to an embodiment of the invention. In general, the spoon 10 comprises a tubular steel cover 12 and a generally tubular refractory lining 14 (partially visible) inside the cover 12. The spoon 10 has an opening 16 at its upper end and a projection 18 at its Lower end. The shape of the cover 12 is complementary to the outer shape of the refractory lining 14 so that the projection 18 corresponds to the shape of a cavity (not visible) to house the treatment agent. The spoon also comprises a lid 20 that can be closed, the inner surface of which defines the second end of the refractory lining 14. The cover 12 and the refractory lining 14 protrude towards the upper end, adjacent to the opening 16 to form a casting channel 17 The spoon 10 is shown in its vertical position so that the casting channel is at the top of the spoon and the cavity is at the bottom of the spoon. In this configuration, the treatment agent can be easily introduced into the cavity through the opening 16.

The spoon 10 is formed by two parts as shown in Figures 1B and 1C. The main body of the spoon 10a is manufactured by placing a forming device 22a inside the cover 12 and filling the space between the cover 12 and the forming device 22a with a refractory material (KALTEK (RTM)). Once the refractory material solidifies, the forming device 22a is removed. Similarly, the projection part of the spoon 10b is made by placing another forming device 22b on the cover corresponding to the projection 18 and filling the space between the forming device 22b and the projection 18 with a refractory material. It is understood that the external surfaces of the forming devices 22a, 22b

they correspond to the shape of the interior of the refractory lining 14 of the spoon. Subsequently, the two parts 10 a, b are joined to each other.

Figure 1C shows a cross-section of the spoon 10 before the forming devices 22a, 22b and without the lid 20 have been removed. The refractory lining 14 comprises a continuous side wall 24, a bottom end 26 (a first end) and because the lid 20 is not adjusted, the spoon is completely open at its upper end. The uppermost part of the continuous side wall defines the position in which the cover 20 fits (the second end 28). The liner 14 of the spoon comprises a cavity 30 for housing the treatment agent. The cavity 30 extends from the first end 26. This provides the advantage that there is a larger metal head above the treatment agent. Note that the walls of the cavity 30 are thicker than the continuous side wall 24. The thicker wall provides additional insulation for the vaporization of the treatment agent.

The height of the interior space when the spoon is in its vertical position is marked with x. The height of the interior space when the spoon pivots to be placed in its horizontal position is marked with and. The depth of the cavity is marked with z. In this embodiment, the approximate values of x, y and z are 1380 mm, 640 mm and 480 mm, respectively. In addition, the ratio of x: y is approximately 2.2: 1 and the ratio of x: z is approximately 2.9: 1.

Figure 1D shows a cross section of the forming device 22a. The external surface of the forming device 22a defines the inner surface of the continuous side wall 24 and also the cross-section of the interior space. The cross section of the shaping device 22a is based on an equilateral triangle in which the corners have been rounded and the sides are bent outwards.

Figure 1E shows a cross section of the forming device 22b. The outer surface of the forming device 22b defines the walls of the cavity 30. In this embodiment, the cross-section of the forming device 22b is related to the cross-section of the forming device 22a (shown with broken lines). Again, the cross section of the forming device 22b is approximately triangular. It is understood that the cavity 30 may have a different cross section, for example, a circular cross section. However, it is thought that a triangular cross-section may be advantageous since it helps retain the treatment agent inside the cavity 30 when the bucket pivots from the vertical position to the horizontal position.

Figure 1F shows a cross-section of the main part of the spoon 10a comprising the cover 12 and the refractory side wall 24. The side wall 24 is based on an equilateral triangle (shown with dotted lines) in which each corner makes contact with the side wall 24. In this embodiment, the length of each side of the triangle is approximately 740 mm, so that The proportion of the height of the interior space, when the spoon is in its vertical position (marked with x in Figure 1C), with respect to the length of a part of the side wall is approximately 1.8: 1. The triangle comprises an inscribed circle (also shown as a dotted line). In this embodiment, the inscribed circle has a diameter of approximately 427 mm so that the proportion of the height of the interior space, when the spoon is in its vertical position (marked with x in Figure 1C) with respect to the length of the Circle diameter is about 3.2: 1.

The proportions of the spoon shown in Figures 1A to 1F are considered particularly beneficial for the treatment of the metal with the treatment agent, combining good heat retention with an effective treatment.

Figures 2A and 2B are schematic drawings of the spoon 10 shown in Figure 1A in its horizontal position. The spoon 10 comprises a first end 26, a second end 28 and a continuous side wall 24, as previously described. In this horizontal configuration, the upper part of the side wall defines the upper part 40 of the interior space and the lower part of the side wall defines the lower part 42 of the interior space. An intermediate vertical plane 44 is shown between the first and second ends. The vertical plane is chosen so that it is closer to the first end 26 than to the second end 28 since this corresponds to a position in which the continuous side wall 24 has a regular shape. A horizontal plane 46 is shown midway between the upper part 40 and the lower part 42 of the interior space. The volume of the interior space defined between the lower part of the interior space 42, the first end 26, the plane 46 halfway and the vertical plane 44 is marked with l (the lower volume). The volume of the interior space defined between the upper part of the interior space 40, the first end 26, the plane 46 halfway and the vertical plane 44 is marked with II (the upper volume). Referring to Figure 2A, volumes I and II appear to be the same but, from Figure 2B, it is clear that volume I is larger than volume 2, due to the cross-sectional shape of the side wall 24 keep going.

The triangular prism shape of the bucket according to an embodiment of the present invention is advantageous compared to the cylindrical bucket, in terms of heat loss of the metal when it is in a horizontal position and of a larger metal head on the agent. of treatment when it is in an upright position (the second position). As is evident from the schematic drawing of Figure 2B, if

fill the spoon halfway, the surface of the metal exposed to the air will be smaller than in a comparable cylindrical spoon. Similarly, when the spoon is pivoted from the horizontal position to the vertical position, the height of metal is greater than that of a comparable cylindrical spoon.

Example 1 and Comparative Example 1: Simulations

In order to accurately assess the rate of heat loss of a spoon according to an embodiment of the present invention (Example 1), the inventors designed two spoons, Example 1 (according to an embodiment of the invention) and another spoon for comparison (Comparative Example 1) and carried out simulations using the MAGMASOFT simulation tool. MAGMASOFT is a leading simulation tool supplied by MAGMA Gie�ereitechnologie GmbH that models mold filling and solidification of the castings. It is typically used in foundries to avoid expensive and prolonged foundry tests.

The spoon of Example 1 is shown in Figure 3A (vertical position) and in Figures 3B and 3C (horizontal position). The interior space has a considerably triangular cross section. Comparative Example 1 is shown in Figure 4A (vertical position) and in Figures 4B and 4C (horizontal position). The interior space has a circular cross section. The dotted lines are shown in each figure to demonstrate the level of molten metal when the spoons are filled to their working capacities. The following table shows a comparison of the properties of the two spoons.

Example 1

Comparative Example 1

Working capacity (kg)

3000 3000

Total surface area of metal volume (mm2)

3719746  3892335

Upper surface area (mm2)

1028446 1354917

Metal height - horizontal (mm)

417.7 427

Metal height - vertical (mm)

897 747

Geometric module (volume / surface area) (cm)

11.5  eleven

As can be seen, even if both spoons contain the same amount of metal, it is filled at different levels due to their different shapes. In the horizontal position, the metal is filled to a similar height in both cases, but when the spoons are rotated to the vertical position, the height of the metal is much greater for Example 1 than for Comparative Example 1. The greater height of the Metal above the vaporizable treatment agent means that the vaporizable treatment agent must travel through more metal and therefore is more likely to remain inside the molten metal, leading to higher recovery rates.

In addition, the total surface area of the metal (in contact with the air or with the bucket walls) and the upper surface area of the metal (in contact with the air) is smaller for Example 1 than for the Comparative Example

1. This corresponds to a larger module for Example 1 than for Comparative Example 1. Therefore, the molten metal of the spoon of Example 1 would cool much faster than the molten metal of the spoon of Comparative Example 1.

In the simulations, the spoon was modeled so that it contained molten steel and presented a refractory lining with insulating properties such as those of the KALTEK (RTM) material. The model considers that the border material above the metal is air. The simulation was carried out at two different starting temperatures (1400 oC and 1580 oC) for the refractory lining. The results after 240 seconds are shown in Figures 5A to 5D. The result of the simulation is a contour diagram formed of the metal, the darkness of the shading being inversely proportional to the temperature of the liquid metal, that is, the darker the shaded area is colder the metal is - current values are indicated by the key temperature in the simulation.

Figure 5A and 5B show the surface temperature of the metal when the refractory lining has a starting temperature of 1400 ° C for Example 1 and for Comparative Example 1 respectively. The surface temperature of the metal is higher for the spoon of the invention than for the comparative example, even if both spoons contain the same amount of metal and have identical starting temperatures. This is observed by the greater proportion of darker contours (shading) of the metal surface of Figure 5B compared to 5A since the darker the colder shading the metal is.

Figures 5C and 5D show the surface temperature of the metal when the refractory lining has a starting temperature of 1580 ° C for Example 1 and for Comparative Example 1 respectively. Again, the surface temperature of the metal is higher for the spoon of the invention than for the comparative example, as shown by the lighter shading of Figure 5C compared to Figure 5D. This shows that the

5 spoon of the invention allows the metal to remain hotter for longer.

Example 2 and Comparative Example 2 - preparation of ductile iron

Ductile iron was prepared using a spoon according to an embodiment of the invention (Example 2) and a standard refractory trough spoon (Comparative Example 2). In each case, the cast iron was treated with ferrosilicon magnesium alloy (FeSiMg). Magnesium recovery was measured after 4 and 9/10 minutes. Be

10 calculated the recovery of magnesium used the following formula:

Mg recovery% = (0.76. (% S in base metal -% residual S) +% residual Mg) x 100 /% Mg added

Example 2

The spoon 10 shown in Figure 1A was placed in an upright position with the cavity 18 at the most point

15 lower. Subsequently, 20.8 kg of ferrosilicon magnesium alloy (5.38% Mg) was introduced into the cavity using a long neck funnel placed in the opening. After introducing the treatment agent, the spoon was rotated 90o to a horizontal position. Subsequently, the spoon was filled with 1600 kg of cast iron at a temperature of 1480 oC. Next, the spoon was rotated again to the vertical position so that the molten iron flowed into the cavity. A custom white flame was observed

20 that molten iron reacted with magnesium alloy. The metal was poured out of the spoon by tilting it and pouring out of the casting channel 17. The results are shown below.

Comparative Example 2

14.4 kg of ferrosilicon magnesium alloy (5.38% Mg) were placed in a recess of a spoon with standard refractory trough and 800 kg of cast iron was poured at a temperature of 1500 oC (standard practice) in the

25 inside the spoon. The results are shown below.

Example 2

Comparative Example 2

4 minutes

10 minutes  4 minutes 9 minutes

Residual Mg (%)

0.0550 0.0474 0.0450 0.0350

S before treatment (%)

0.0140 0.0140 0.0070 0.0070

S after treatment (%)

0.0110 0.0104 0.0046 0.0040

Mg added (%)

0.06994 0.06994 0.09684 0.09684

Mg recovery (%)

82 72 48 38

The magnesium recovery is considered to be greater for Example 2 than for Comparative Example 2. Therefore, it appears that the spoon according to an embodiment of the present provides better recovery rates than the standard refractory trough spoon.

Claims (15)

one.

 A treatment spoon comprising a spoon cover containing a refractory and generally tubular spoon liner, said spoon being able to pivot between a horizontal position and a vertical position,

said spoon covering having a first end and a second end with a continuous side wall between them, an interior space being defined between said first and second ends and the continuous side wall, said spoon covering additionally comprising a cavity for housing a treatment agent, said cavity being located adjacent to the first end and in fluid communication with the interior space and placed closer to the top than to the bottom of the interior space when the spoon is in its horizontal position and closer to the lower part than the upper part of the interior space when the spoon is in its vertical position, and a casting channel to receive and pour the molten metal located closer to the upper part than to the lower part of the interior space when to the spoon it is in its horizontal and vertical positions, in which in the horizontal position, e The smaller volume of the interior space defined below a plane halfway between the top and bottom of the interior space and between the first end and an intermediate vertical plane between the first and second ends is greater than the upper volume of the defined interior space above the plane midway and between the first end and said vertical plane.

2.

 The spoon according to claim 1, wherein the cavity extends from the first end of the spoon liner out of the interior space.

3.

 The spoon according to claim 1 or claim 2, wherein the ratio of the lower volume to the higher volume is at least 1.5: 1.

Four.

 The spoon according to any one of the preceding claims, wherein the proportion of the height of the interior space when the spoon is in its vertical position with respect to the height of the interior space when the spoon is in its horizontal position is of at least 2: 1.

5.

 The spoon according to any one of the preceding claims, wherein the proportion of the height of the interior space when the spoon is in its vertical position with respect to the height of the interior space when the spoon is in its horizontal position does not It's more than 6: 1.

6.

 The spoon according to any one of the preceding claims, wherein the cavity extends from the first end of the liner of the spoon out of the interior space and the proportion of the atura of the interior space when the spoon is in position Vertical with respect to the length of the cavity is at least 2: 1.

7.

 The bucket according to any one of the preceding claims, wherein the side wall is defined by three or more wall parts such that the cross section of the continuous side wall is considerably polygonal.

8.

 The bucket according to claim 7, wherein the continuous side wall is defined by three wall parts, so that the cross section of the continuous side wall is considerably triangular.

9.

 The bucket according to claim 7 or 8, wherein the corners of the polygon are rounded and / or the sides of the polygon are curved outward.

10.

 The bucket according to any one of the preceding claims, wherein the continuous side wall is defined by three side wall parts, such that the cross-section of the side wall is considerably triangular and the proportion of the height of the interior space when the spoon is in its vertical position with respect to the length of at least one of the parts of the side wall is at least 1.5: 1.

eleven.

 The spoon according to any one of the preceding claims, wherein the side wall is of unitary construction.

12.

The spoon according to any one of the preceding claims, wherein the spoon cover and the spoon coating have considerably the same shape.

13.

 A process for the treatment of molten metal which comprises loading the spoon of any one of claims 1 to 12 by placing a treatment agent in the cavity, filling the spoon with molten metal while it is in its horizontal position to a level below the cavity, and pivoting the spoon to its vertical position so that molten metal flows over the cavity treatment agent.

14.

 The method of claim 13, wherein the bucket is pivoted more than 90 ° from the horizontal position,

through the vertical position to a distribution position in which the treated metal is distributed through the casting channel.

fifteen.

 The method of claim 13 or 14, wherein the treatment agent is a nodularizer.