Patent Description:
Metallurgical furnaces (e.g., an electric arc furnace or a ladle metallurgical furnace) are used in the processing of molten metal materials. The electric arc furnace heats charged metal in the furnace by means of an electric arc from a graphite electrode. The electric current from the electrode passes through the charged metal material forming a molten bath of the metal materials. The furnaces house the molten materials during the processing of the molten materials forming molten steel and slag (a stony waste material).

A metallurgical furnace as above described is typically made of steel, aluminum, aluminum base alloys, copper, copper base alloys and metals having similar thermal characteristics and have metal slag retainers, made from the aforesaid metals attached to the furnace side of the metal closure elements. Examples of metallurgical furnaces with slag retainers are described for example in patent documents <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>. These slag retainers, typically cup-shaped to aid in slag retention and being unprotected from the high furnace temperatures, have a relatively short life due to overheating and oxidation. The use of the more oxidation resistant and thermally conductive materials in the slag retainers would result in substantially higher cost without commensurate benefit. The furnace must be shut down to replace or install new slag retainers, which is often down with refurbishing the sidewall of the furnace. Thus, replacing slag retainers is a costly endeavor.

Therefore, there is a need for an improved a furnace sidewall having slag retainers and metallurgical furnaces having the same.

The present invention is defined as set out in the appended independent claims. Embodiments of the invention are defined as set out in the appended dependent claims. A furnace sidewall having slag retainers and metallurgical furnaces having the same are disclosed herein. In one embodiment, a furnace sidewall comprises a hot plate having an inner surface facing configured to face an interior volume of a metallurgical furnace and a bottom surface configured to face a hearth of the metallurgical furnace. The furnace sidewall further comprises a plurality of slag retainers extending inwardly from the inner surface of the hot plate, the plurality of slag retainers arranged in a macro-pattern of slag retainer groups. The slag retainer groups comprise at least two or more of the slag retainers arranged in a micro-pattern. Each slag retainer of a common slag retainer group comprising the micro-pattern is a rectangular steel stud welded to the inner surface of the hot plate, wherein the rectangular steel studs of the common slag retainer group spaced apart from one another defining gaps therebetween. At least two of the rectangular steel studs within the common slag retainer group have different orientations, wherein the gaps defined between the rectangular steel studs of the common slag retainer group are smaller than a distance between adjacent groups of slag retainers, and wherein each slag retainer group comprises two side rectangular steel studs and a bottom rectangular steel stud arranged in a cup or horse-shoe shape which is open to a top of the furnace sidewall. Each side rectangular steel stud includes a major surface that is diagonally oriented. The bottom rectangular steel stud includes a major surface that is coplanar with a horizontal axis. A funnel shaped opening is provided between the side rectangular steel studs of each group.

In another embodiment, a furnace sidewall comprises a ring-shaped steel hot plate having an inner surface facing inward. The furnace sidewall comprises a plurality of slag retainers welded to the inner surface of the hot plate, wherein the slag retainers projecting inward from the inner surface. The plurality of slag retainers are arranged in a pattern of discrete slag retainer groups. The slag retainer groups have a substantially similar micro-pattern comprised of at least two spaced apart slag retainers of the plurality of slag retainers. Each of the two spaced apart slag retainers is a rectangular steel stud having different geometric orientations. The two spaced apart rectangular steel studs of the common slag retainer group define a gap therebetween that is smaller than a distance between adjacent groups of slag retainers, wherein each slag retainer group comprises two side rectangular steel studs and a bottom rectangular steel stud arranged in a cup or horse-shoe shape which is open to a top of the furnace sidewall. Each side rectangular steel stud includes a major surface that is diagonally oriented. The bottom rectangular steel stud includes a major surface that is coplanar with a horizontal axis. A funnel shaped opening is provided between the side rectangular steel studs of each group.

In yet another embodiment, a metallurgical furnace is provided. The metallurgical furnace comprises a hearth. The metallurgical furnace comprises a sidewall disposed on the hearth and surrounding an interior volume of the metallurgical furnace. The sidewall comprises a hot plate having an inner surface facing the interior volume. The sidewall comprises a cover plate surrounding the hot plate in a spaced-apart relation. The sidewall comprises a plurality of spray nozzles disposed in a volume defined between the cover plate and hot plate, the spray nozzles oriented to spray a liquid on the hot plate. The sidewall comprises a plurality of slag retainers welded to the inner surface of the hot plate, the slag retainers projecting inward from the inner surface. The plurality of slag retainers are arranged in a pattern of discrete slag retainer groups. At least two of the slag retainer groups have a substantially similar micro-pattern comprised of at least two spaced apart slag retainers of the plurality of slag retainers. Each of the two spaced apart slag retainers is a rectangular steel stud having different geometric orientations. The two spaced apart rectangular steel studs of the common slag retainer group define a gap therebetween that is smaller than a distance between adjacent groups of slag retainers, wherein each slag retainer group comprises two side rectangular steel studs and a bottom rectangular steel stud arranged in a cup or horse-shoe shape which is open to a top of the sidewall. Each side rectangular steel stud includes a major surface that is diagonally oriented. The bottom rectangular steel stud includes a major surface that is coplanar with a horizontal axis. A funnel shaped opening is provided between the side rectangular steel studs of each group.

So that the way the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings.

It is contemplated that elements disclosed in one embodiment may be beneficially utilized with other embodiments without specific recitation.

The present invention is directed to a furnace sidewall having slag retainers and metallurgical furnaces having the same. The sidewall of the metallurgical furnace includes a spray-cooled hot plate that faces the interior of the furnace. Slag retainers are disposed on the hot plate. The slag retainers enhance the ability of the hot plate to hold and retain slag on the surface of the sidewall facing the interior of the furnace. The retained slag functions to insulate and protect the hot plate, thereby extending the service life of the hot plate. Groups of slag retainers are arranged in a macro-pattern across the surface of the hot plate. The slag retainers comprising each group are arranged in a micro-pattern that includes at least two slag retainers. The micro-pattern is repetitive across the macro-pattern. While not detailed herein, a macro slag retainer pattern comprising micro-patterns of slag retainers may also be provided on an inner surface of a hot plate of other spray-cooled components utilized in the furnace, such as a spray-cool roof that is disposed on the sidewall.

<FIG> illustrates an elevational side view of a metallurgical furnace <NUM> having a spray-cooled roof <NUM> removably disposed on a furnace body <NUM>. The body <NUM> includes a spray-cooled sidewall <NUM> disposed on a hearth <NUM>. The hearth <NUM> is lined with refractory brick <NUM>. The sidewall <NUM> has a top <NUM>. The spray-cooled roof <NUM> is moveably disposed on the top <NUM> of the sidewall <NUM>. The spray-cooled roof <NUM> and furnace body <NUM> enclose an interior volume <NUM> of the metallurgical furnace <NUM>. The interior volume <NUM> may be loaded or charged with material <NUM>, e.g., metal, scrap metal, or other meltable material, which is to be melted within the metallurgical furnace <NUM>.

The metallurgical furnace <NUM>, including the body <NUM> and the spray-cooled roof <NUM>, is rotatable along a tilt axis <NUM>. The metallurgical furnace <NUM> may be tilted in a first direction about the tilt axis <NUM> toward the slag door (not shown) multiple times during a single batch melting process, sometimes referred to as a "heat", to remove slag. Similarly, the metallurgical furnace <NUM> may be tilted in a second direction about the tilt axis <NUM> towards a tap spout (not shown) multiple times during a single batch melting process including one final time to remove the molten material <NUM>.

Roof lift members <NUM> may be attached at a first end to the spray-cooled roof <NUM>. The roof lift members <NUM> may be chains, cables, ridged supports, or other suitable mechanisms for supporting the spray-cooled roof <NUM>. The roof lift members <NUM> may be attached at a second end to one or more mast arms <NUM>. The mast arms <NUM> extend horizontally and spread outward from a mast support <NUM>. The mast support <NUM> may be supported by a mast post <NUM>. A coupling <NUM> may attach the mast post <NUM> to the mast support <NUM>. The mast support <NUM> may rotate about the coupling <NUM> and the mast post <NUM>. Alternately, the mast post <NUM> may rotate with the mast support <NUM> for moving the roof lift members <NUM>. In yet other examples, roof lift members <NUM> may be aerially supported to move the spray-cooled roof <NUM>. The spray-cooled roof <NUM> may be configured to swing or lift away from the sidewall <NUM>. The spray-cooled roof <NUM> is lifted away from the sidewall <NUM> to expose the interior volume <NUM> of the metallurgical furnace <NUM> through the top <NUM> of the sidewall <NUM> for loading material therein.

At least the sidewall <NUM> of the body <NUM> may be ring, oval or circular-shaped when viewed from a top plan view, of which a portion is shown in <FIG>. Likewise, the spray-cooled roof <NUM> a shape complimentary to that of the sidewall <NUM> so that the interior volume <NUM> may be enclosed.

A central opening <NUM> may be formed through the spray-cooled roof <NUM>. Electrodes <NUM> extend through the central opening <NUM> from a position above the spray-cooled roof <NUM> into the interior volume <NUM>. During operation of the metallurgical furnace <NUM>, the electrodes <NUM> are lowered through the central opening <NUM> into the interior volume <NUM> of the metallurgical furnace <NUM> to provide electric arc-generated heat to melt the material <NUM>.

The spray-cooled roof <NUM> may further include an exhaust port to permit removal of fumes generated within the interior volume <NUM> of the metallurgical furnace <NUM> during operation.

<FIG> illustrates a partial horizontal sectional view of the sidewall <NUM> of the metallurgical furnace <NUM> of <FIG>. The sidewall <NUM> comprises a hot plate <NUM> and a cover plate <NUM>, both of which are shown in cross-section in <FIG>. The hot plate <NUM> is coupled in a spaced apart relation to the cover plate <NUM>. Like the sidewall <NUM>, the hot plate <NUM> and the cover plate <NUM> have a ring, oval or circular-shape, a section of which is shown in <FIG>. The hot plate <NUM> is fabricated from steel or other suitable material. An inner surface <NUM> of the hot plate <NUM> faces the interior volume <NUM> of the metallurgical furnace <NUM> (shown in <FIG>) and an outer surface <NUM> of the cover plate <NUM> faces ambient environment where the metallurgical furnace <NUM> is utilized.

A manifold <NUM> is provided in the volume between the cover plate <NUM> and the hot plate <NUM>. A plurality of nozzles <NUM> are coupled to the manifold <NUM>. Liquid, such as water, is provided through the manifold <NUM> to the nozzles <NUM> such that the liquid may be sprayed through the nozzles <NUM> onto an outer surface <NUM> of the hot plate <NUM>. The liquid is utilized to cool the hot plate <NUM> during operation of the metallurgical furnace <NUM> to prevent damage to the sidewall <NUM>.

A plurality of slag retainers <NUM> are coupled to the inner surface <NUM> of the hot plate <NUM>. The plurality of slag retainers <NUM> are arranged in a pattern <NUM>. The pattern <NUM> generally includes a repetitive micro-pattern, where the micro-pattern includes at least two slag retainers <NUM> of the plurality of slag retainers <NUM> that have different geometric orientations, as further discussed below with reference to <FIG>. However, the pattern <NUM> may alternatively comprise a repetitive pattern of capacitively discharge welded high aspect ratio slag retainers <NUM>. A high aspect ratio slag retainers <NUM> is one that has a height at least <NUM>, for example <NUM> to <NUM>, times the mean width of the surface of the slag retainer <NUM> that is welded to the hot plate <NUM>. The slag retainers <NUM> project from the inner surface <NUM> of the hot plate <NUM> into the interior volume <NUM> of the metallurgical furnace <NUM>. The pattern <NUM> of the slag retainers <NUM> is configured to trap slag produced by a batch melting process in the metallurgical furnace <NUM> so that the slag retained to the hot plate <NUM> by the slag retainers <NUM> functions to insulate the hot plate <NUM> from the heat generated in the interior volume <NUM> of the metallurgical furnace <NUM> during operation of the furnace <NUM>.

While the pattern <NUM> of slag retainers <NUM> are described in <FIG> as being provided on the inner surface <NUM> of the hot plate <NUM>, the pattern <NUM> of slag retainers <NUM> may also be provided on an inner surface of a hot plate of the spray-cooled roof <NUM> of <FIG>.

<FIG> are schematic elevation views of various patterns of slag retainers, which may be utilized as the pattern <NUM> of <FIG>. The patterns of at least <FIG> generally include a macro-pattern made up of groups of slag retainers having a repetitive micro-pattern. It is contemplated that other patterns may be utilized.

In an unclaimed embodiment, <FIG> shows a macro-pattern <NUM> of slag retainer groups <NUM>. Each slag retainer groups <NUM> includes at least two slag retainers <NUM>. Some of the groups <NUM> illustrated in <FIG> are bounded by a dashed line to better illustrate the discrete repetitive nature of the groups <NUM> within the overall pattern of the macro-pattern <NUM>. The slag retainers <NUM> comprising each group <NUM> are arranged in micro-pattern. Each group <NUM> of slag retainers <NUM> comprising the macro-pattern <NUM> include at least two slag retainers <NUM> having different geometric orientations. Adjacent groups <NUM> of slag retainers <NUM> of the macro-pattern <NUM> may have slag retainers <NUM> arranged in a substantially same micro-pattern that repeat over the inner surface <NUM> of the hot plate <NUM>. Alternatively, the micro-pattern of one group <NUM> may include slag retainers <NUM> arranged in a geometric pattern that is different than a micro-pattern of another group <NUM> of slag retainers <NUM> comprising the macro pattern <NUM>. In yet another example, the micro-pattern of one group <NUM> may include more slag retainers <NUM> than a micro-pattern of another group <NUM> of slag retainers <NUM> comprising the macro pattern <NUM>.

Each slag retainer <NUM> is a steel stud. The steel stud has a rectangular cross-section and a height (the height extending out of the page). In another example, the steel stud may have a circular, oval or other cross-sectional profile. In one example the steel stud has a high aspect ratio in that the height of the stud is at least <NUM> times, such as <NUM> to <NUM>, greater than the average width of the rectangular cross-section.

The space between each of the slag retainers <NUM> comprising a common group <NUM> is less than a space between neighboring groups <NUM> such that the discrete identification of the individual groups <NUM> is readily apparent. However, the spacing between slag retainers <NUM> comprising a common group <NUM> may be substantially equal to the space between neighboring groups <NUM>.

The slag retainers <NUM> comprising an individual group <NUM> may be arranged in a wave, spiral, curve, linear, off-set, polygonal, quadrilateral, triangular, truncated triangle, letter-shaped (e.g., C, L, T, S, U, X, V, and W, among others) or other geometrical orientation. Quadrilateral shapes include rectangle, square, trapezoid, diamond and the like. At least two slag retainers <NUM> of the same group <NUM> have a different geometric orientation. Alternatively or in addition, one or more retainers <NUM> of the same group <NUM> have a common geometric orientation. In one example, each slag retainer <NUM> of a common group <NUM> is separated by a space or gap.

In the unclaimed embodiment depicted in <FIG>, each group <NUM> of slag retainers <NUM> includes four slag retainers <NUM> arranged in a diamond orientation. For example, each of the slag retainers <NUM> includes a major surface <NUM> that is diagonally oriented, for example at an angle <NUM> of about <NUM> degrees from a vertical axis <NUM> or a horizontal axis <NUM>. The vertical axis <NUM> is generally aligned in the same direction as the central vertical axis of the sidewall <NUM>. Each slag retainer <NUM> within a common group <NUM> is spaced to form a gap <NUM> the neighboring slag retainer <NUM> the common group <NUM> of slag retainers <NUM>. A dashed box <NUM> shown in <FIG> represents a square foot, and the macro-pattern <NUM> comprises approximately <NUM> slag retainers <NUM> per square foot, although the density of slag retainers <NUM> may be different or even vary within the pattern <NUM>.

<FIG> shows a macro-pattern <NUM> comprising a plurality of groups <NUM> of slag retainers <NUM>. Each group <NUM> of the slag retainers <NUM> comprising the macro-pattern <NUM> includes at least two slag retainers <NUM> that are fixed to the inner surface <NUM> of the hot plate <NUM> (as shown in <FIG>). The groups <NUM> comprising the macro-pattern <NUM> may include slag retainers <NUM> having substantially the same geometric orientation of slag retainers <NUM> that repeat over the inner surface <NUM> of the hot plate <NUM>. Alternatively, some or all the groups <NUM> comprising the macro-pattern <NUM> may include slag retainers <NUM> having different geometric orientations of slag retainers <NUM>. According to the invention and as depicted in <FIG>, each group <NUM> of slag retainers <NUM> includes at least three slag retainers <NUM> arranged in a cup or horse-shoe shape which is open to the top of the sidewall <NUM>. Each group <NUM> of slag retainers <NUM> comprises two side plates <NUM> and a bottom plate <NUM>. Each side plate <NUM> includes a major surface <NUM> that is diagonally oriented, for example at an angle <NUM> of about <NUM> degrees from a vertical axis <NUM>. Each of the bottom plates <NUM> includes a major surface <NUM> that is coplanar with a horizontal axis <NUM>. Each of the slag retainers <NUM> is spaced to form two gaps <NUM> between the bottom plate <NUM> and the side plates <NUM> within each group <NUM>. A funnel shaped opening <NUM> is provided between the side plates <NUM> of each group <NUM>. A dashed box <NUM> shown in <FIG> represents a square foot, and the macro-pattern <NUM> of slag retainers <NUM> comprises approximately <NUM> slag retainers <NUM> per square foot, although the density of slag retainers <NUM> may be different or even vary within the pattern <NUM>.

In an unclaimed embodiment, <FIG> shows a macro-pattern <NUM> of slag retainers <NUM> comprising a plurality of groups <NUM>. Each group <NUM> of slag retainers <NUM> comprise a plurality of slag retainers <NUM> that are fixed to the inner surface <NUM> of the hot plate <NUM> (as shown in <FIG>). The groups <NUM> comprising the macro-pattern <NUM> may include slag retainers <NUM> having substantially the same geometric orientation of slag retainers <NUM> that repeat over the inner surface <NUM> of the hot plate <NUM>. Alternatively, some or all the groups <NUM> comprising the macro-pattern <NUM> may include slag retainers <NUM> having different geometric orientations of slag retainers <NUM>.

Each of the groups <NUM> illustrated in <FIG> comprises four slag retainers <NUM> in a rectangular or box shape. For example, each of the slag retainers <NUM> include a major surface <NUM> that is oriented along (e.g., an angle of about <NUM> relative to) a vertical axis <NUM> and a horizontal axis <NUM>. Each of the slag retainers <NUM> is spaced to form four gaps <NUM> within each group <NUM>. A dashed box <NUM> shown in <FIG> represents a square foot, and the macro-pattern <NUM> of slag retainers <NUM> comprises approximately <NUM> slag retainers <NUM> per square foot, although the density of slag retainers <NUM> may be different or even vary within the pattern <NUM>.

In an unclaimed embodiment, <FIG> shows another pattern <NUM> comprising a plurality of slag retainers <NUM> in elevation view. Each of the slag retainers <NUM> include a rectangular cross-section and a height (the height extending out of the page). In this example, each of the slag retainers <NUM> includes a length <NUM> (along the Y-X plane) and a width <NUM> (along the Y-Z plane), and the length <NUM> is greater than the width <NUM>. As described herein, the pattern <NUM> comprises a pattern of rows <NUM> staggered with respect to a pattern of columns <NUM> consisting of the slag retainers <NUM> such that vertical gaps <NUM> and lateral gaps <NUM> are formed between the slag retainers <NUM> in the columns <NUM> and the rows <NUM>, respectively. One or both of the pattern of rows <NUM> and the pattern of columns <NUM> may be linear or non-linear. As described herein, the lateral gaps <NUM> correspond with the width <NUM> and the vertical gaps <NUM> correspond with the length <NUM> of an adjacent slag retainer <NUM>. The pattern of rows <NUM> and/or the pattern of columns <NUM> may be a micro-pattern within the pattern <NUM> (e.g., a macro-pattern). For example, a micro-pattern <NUM> may include two or more diagonally oriented slag retainers <NUM>.

In an unclaimed embodiment, <FIG> shows another pattern <NUM> comprising a plurality of slag retainers <NUM> in elevation view. Each of the slag retainers <NUM> include a rectangular cross-section and a height (the height extending out of the page). In this example, each of the slag retainers <NUM> includes the length <NUM> (along the Y-X plane) and the width <NUM> (along the Y-Z plane), and the length <NUM> is greater than the width <NUM>. As described herein, the pattern <NUM> comprises the pattern of rows <NUM> and a pattern of columns <NUM> consisting of the slag retainers <NUM> such that vertical gaps <NUM> and lateral gaps <NUM> are formed between the slag retainers <NUM> in the columns <NUM> and the rows <NUM>, respectively. One or both of the pattern of rows <NUM> and the pattern of columns <NUM> may be linear or non-linear. As described herein, the lateral gaps <NUM> correspond with a fraction of the width <NUM> and the vertical gaps <NUM> correspond with the length <NUM> of an adjacent slag retainer <NUM>. The pattern of rows <NUM> and/or the pattern of columns <NUM> may be a micro-pattern within the pattern <NUM> (e.g., a macro-pattern). In this example, a micro-pattern <NUM> may include two or more diagonally oriented slag retainers <NUM>. The micro-pattern <NUM> differs from the micro-pattern <NUM> as the slag retainers <NUM> of the micro-pattern <NUM> at least partially overlap in the Z direction, whereas the slag retainers <NUM> of the micro-pattern <NUM> of <FIG> do not.

In an unclaimed embodiment <FIG> shows another pattern <NUM> comprising a plurality of slag retainers <NUM> in elevation view. Each of the slag retainers <NUM> include a rectangular cross-section and a height (the height extending out of the page). In this example, each of the slag retainers <NUM> includes the length <NUM> (along the Y-X plane) and the width <NUM> (along the Y-Z plane), and the length <NUM> is greater than the width <NUM>. As described herein, the pattern <NUM> comprises a pattern of rows <NUM> aligned with respect to a pattern of columns <NUM> consisting of the slag retainers <NUM> such that vertical gaps <NUM> and lateral gaps <NUM> are formed between the slag retainers <NUM> in the columns <NUM> and the rows <NUM>, respectively. One or both of the pattern of rows <NUM> and the pattern of columns <NUM> may be linear or non-linear. As described herein, the lateral gaps <NUM> correspond with the width <NUM> and the vertical gaps <NUM> are aligned. The lateral gaps <NUM> also correspond with the length <NUM> of an adjacent slag retainer <NUM>. A micro-pattern <NUM> in <FIG> may include two or more adjacent vertically oriented slag retainers <NUM>. The micro-pattern <NUM> may repeat, as necessary, with thin the pattern <NUM> (e.g., a macro-pattern).

In an unclaimed embodiment, <FIG> shows another pattern <NUM> comprising a plurality of slag retainers <NUM> in elevation view. Each of the slag retainers <NUM> include a rectangular cross-section and a height (the height extending out of the page). In this example, each of the slag retainers <NUM> includes the length <NUM> (along the Y-X plane) and the width <NUM> (along the Y-Z plane), and the width <NUM> is greater than the length <NUM>. As described herein, the pattern <NUM> comprises a pattern of rows <NUM> aligned with respect to a pattern of columns <NUM> consisting of the slag retainers <NUM> such that vertical gaps <NUM> and lateral gaps <NUM> are formed between the slag retainers <NUM> in the columns <NUM> and the rows <NUM>, respectively. One or both of the pattern of rows <NUM> and the pattern of columns <NUM> may be linear or non-linear. As described herein, the lateral gaps <NUM> correspond with a fraction of the width <NUM> and the vertical gaps <NUM> correspond with the length <NUM>. Additionally, the vertical gaps <NUM> are aligned. The lateral gaps <NUM> also correspond with the length <NUM> of an adjacent slag retainer <NUM>.

In an unclaimed embodiment, <FIG> shows another pattern <NUM> comprising a plurality of slag retainers <NUM> in elevation view. Each of the slag retainers <NUM> include a rectangular cross-section and a height (the height extending out of the page). In this example, each of the slag retainers <NUM> includes the length <NUM> (along the Y-X plane) and the width <NUM> (along the Y-Z plane), and the width <NUM> is greater than the length <NUM>. As described herein, the pattern <NUM> comprises a pattern of rows <NUM> that are staggered with respect to a pattern of columns <NUM> consisting of the slag retainers <NUM> such that vertical gaps <NUM> and lateral gaps <NUM> are formed between the slag retainers <NUM> in the columns <NUM> and the rows <NUM>, respectively. One or both of the pattern of rows <NUM> and the pattern of columns <NUM> may be linear or non-linear. As described herein, the lateral gaps <NUM> correspond with the width <NUM> and the vertical gaps <NUM> correspond with a fraction of the length <NUM>. Additionally, the vertical gaps <NUM> are aligned while the lateral gaps <NUM> are staggered. A micro-pattern <NUM> may include two or more diagonally oriented slag retainers <NUM>.

<FIG> are schematic partial cross-sectional views depicting a method for fixing the slag retainers <NUM> to the inner surface <NUM> of the hot plate <NUM> to form the micro-patterns and the macro-patterns described above, among other patterns. The method described in <FIG> is a capacitive discharge (CD) welding process but other joining processes may be utilized to fix the slag retainers <NUM> to the hot plate <NUM>. Examples include brazing or arc welding processes, such as shielded metal arc welding (SMAW), flux-core arc welding (FCAW), gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), among other welding processes.

In particular, the CD welding process is particularly efficient at welding the slag retainers <NUM> having high aspect ratios to the hot plate <NUM>. Thus, the method described over the sequence illustrated in <FIG> is particularly useful in fabricating new sidewalls, and rebuilding and refurbishing hotplates for reuse in sidewalls.

In <FIG>, the slag retainer <NUM> is shown positioned on the inner surface <NUM> of the hot plate <NUM>. A ceramic ferrule <NUM> surrounds the slag retainer <NUM> and contacts the inner surface <NUM> of the hot plate <NUM>. The slag retainer <NUM> may be supported by a stud welding gun (not shown) that urges the slag retainer <NUM> against the inner surface <NUM> of the hot plate <NUM> in a direction shown by arrow <NUM> illustrated in <FIG>.

<FIG>, the stud welding gun is triggered. The stud welding gun has a lift mechanism that lifts the slag retainer <NUM> slightly away from the inner surface <NUM> of the hot plate <NUM> in a direction shown by arrow <NUM> illustrated in <FIG> when triggered. Additionally, the stud welding gun produces an electric arc <NUM> between a tip of the slag retainer <NUM> and the inner surface <NUM> of the hot plate <NUM>. The electric arc melts a base area <NUM> of the slag retainer <NUM> and a portion of the inner surface <NUM> of the hot plate <NUM>. The base area <NUM> of the slag retainer <NUM> may be pointed or include a nub to enhance formation of the arc <NUM>.

<FIG> illustrates the arc <NUM> which joins the slag retainer <NUM> to the inner surface <NUM> of the hot plate <NUM>. A timer may stop the electrical current that produces the arc <NUM>. The ceramic ferrule <NUM> concentrates the heat produced by the arc <NUM>. The ceramic ferrule <NUM> also functions to contain the molten material in the weld area. The lift mechanism of the stud welding gun is also de-energized which causes the slag retainer <NUM> to plunge into the molten material in the direction of the arrow <NUM> illustrated in <FIG>.

<FIG> shows the slag retainer <NUM> joined to the inner surface <NUM> of the hot plate <NUM> by a weld <NUM>. The weld <NUM> is produced by the solidification of the molten material produced by the arc <NUM> once the current to the slag retainer <NUM> is terminated. The ceramic ferrule <NUM> is also removed from the slag retainer <NUM> in <FIG>.

The process illustrated in <FIG> is be repeated to recreate groups of slag retainers arranged in micro-patterns that are part of a larger macro-pattern of slag retainers CD welded to the hot plate. The process illustrated in <FIG> may also be utilized to replace one or more slag retainers in an existing macro-pattern, or to add additional slag retainers to existing groups or to create new groups of slag retainers in an existing macro-pattern.

The micro-patterns comprising the slag retainers <NUM> that form the macro slag retainer patterns as described above are less costly to manufacture as opposed to conventional slag retainer designs. The conventional slag retainers are typically complicated shapes that may not be compatible to CD welding processes. This makes the conventional slag retainers much more costly and time consuming to install. For example, one conventional slag retainer pattern includes a four-sided slag retainer structure that resembles a U shape or horseshoe shape in cross-section. In this particular pattern, there are approximately <NUM> slag retainer structures per square foot of hot plate (e.g., thousands of slag retainer structures per roof or sidewall). According to embodiments described herein, there are more slag retainers <NUM> per square foot to complete a good slag retainer coverage scheme, the slag retainers <NUM> can be installed at a rate of about <NUM> slag retainer studs per minute as compare to welding one conventional slag retainer structure, which takes several minutes.

Claim 1:
A furnace sidewall (<NUM>) comprising:
a hot plate (<NUM>) having an inner surface (<NUM>) facing configured to face an interior volume (<NUM>) of a metallurgical furnace (<NUM>) and a bottom surface configured to face a hearth (<NUM>) of the metallurgical furnace; and
a plurality of slag retainers (<NUM>) extending inwardly from the inner surface of the hot plate, the plurality of slag retainers arranged in a macro-pattern (<NUM>) of slag retainer groups (<NUM>), the slag retainer groups comprising at least two or more of the slag retainers arranged in a micro-pattern, each slag retainer of a common slag retainer group comprising the micro-pattern is a rectangular steel stud welded to the inner surface of the hot plate, the rectangular steel studs of the common slag retainer group spaced apart from one another defining gaps therebetween, at least two of the rectangular steel studs within the common slag retainer group having different orientations, wherein the gaps defined between the rectangular steel studs of the common slag retainer group are smaller than a distance between adjacent groups of slag retainers, wherein each slag retainer group (<NUM>) comprises two side rectangular steel studs (<NUM>) and a bottom rectangular steel stud (<NUM>) arranged in a cup or horse-shoe shape which is open to a top of the furnace sidewall (<NUM>), wherein each side rectangular steel stud (<NUM>) includes a major surface that is diagonally oriented and the bottom rectangular steel stud (<NUM>) includes a major surface that is coplanar with a horizontal axis and a funnel shaped opening (<NUM>) is provided between the side rectangular steel studs (<NUM>) of each group.