Repairings and maintenance of hot zone processing equipments of di pipe manufacturing process
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Filing Date
- 2026-02-06
- Publication Date
- 2026-08-13
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Figure IMGF000002_0001
Abstract
Description
REPAIRINGS AND MAINTENANCE OF HOT ZONE PROCESSING EQUIPMENTS OF DI PIPE MANUFACTURING PROCESSFIELD OF INVENTION
[0001] The embodiments of present disclosure are in general related to the improvement of ductile iron spun pipe manufacturing process and more particularly but not exclusively related to the hot zone repair and / or maintenance of ductile iron spun pipe manufacturing process through the repairing / maintenance of processing and handling equipment. The present invention results in enhancement of productivity and production capacity of Ductile Iron Spun Pipe manufacturing.BACKGROUND
[0002] There are several real-world pipe manufacturing processes / techniques such as cold forging, hot forging, piercing, cold drawing, hot drawing, welded, spun pipe, true forming, and Pilgering etc. Among all, spun pipe manufacturing technology is popular for both ferrous and non-ferrous metal.
[0003] Ductile Iron Spun pipe has been quite popular for the last 75 years, around immediately after World War II, in developed economy worldwide. Ductile Iron spun pipe has helped humanity. Ductile iron spun pipe technology supersedes cast iron Spun Pipe Technology. The manufacturing of ductile iron spun pipes, its ligation, maintenance, and replacement is quite easy and scientific. The pipe is manufactured using centrifugal casting in metal moulds or resin lined moulds. In the coming time, for safe drinking water, sewage, gas line and ExtraLarge Tunnel, Ductile Iron Spun Pipe will be quite popular.
[0004] This Ductile Iron Spun pipe manufacturing practice is quite challenging, because of the applicability of all the aspects of engineering, thermodynamics, and refractory. Ductile Iron Spun pipe manufacturing depends on efficiency & usage ofHot Zone. The one of the major problems associated with the Hot Zone of the Ductile Spun Manufacturing is Slag formation and accumulation. There are different type, volume and nature of slag forms and accumulates atprocessing and handling equipments of hot zone area. These accumulation of slag leads to reduction of volumes of handling equipment, which reduces efficiency in discharge of liquid metal, complete metal tap -out, higher liquid metal temperature Loss. This temperature loss leads to less fluidity causing turbulent discharge of liquid metal. The repeated slag accumulation creates number of difficulties in manufacturing process.
[0005] Therefore, frequent slag removal is required which is preferably removed by various application of pearlite ore also termed as Slag coagulants, but still sticky slag remains atthe vertical wall surface of handling equipments. Often these slags are further removed mechanically that lead to the localized damages; majorly to the surface of processing refractory as well as handling equipments of hot zone. Further, this slag results in reduction in life of equipments, higher pinhole rejection, high pressure leak rejection, and overall reduces production capacity.
[0006] These Ductile Iron Spun Pipe plants are continuously running for 24x7, thus there is no surplus time for prevention as well as breakdown maintenance and there is a requirement for frequent replacement of parts / equipments and maintaining extra inventory; that incurs unnecessary high capital cost and operational cost.
[0007] CN103382395A discloses a thermal-state lining repairing method for coke oven ascending pipes. A spray repairing material for the thermal-state lining repairing method of the coke oven ascending pipes includes, by weight, 55-75% of flint clay (or synthetic mullite grains or high-aluminum bauxite), 10-25% of high-aluminum cement, 4-8% of expanding agent, 4-6% of soft clay powder, 5-expanding agent is kyanite, and the additive is naphthalene sulfonic-formaldehyde condensates.
[0008] JP2003171715A discloses a refractory material for repairing, wherein a damaged portion such as a damaged dip tube such as a vacuum degassing tank is immersed in a tubular container and the damaged portion such as the dip tube is filled with a repair refractory material for repair. 0.5 to 2 aluminum phosphate based on 100% by weight of refractory raw material. A refractory for hot repair such as dipping pipes in a vacuum degassing tank, characterized by containing 0% by weight.
[0009] KR20030041539A discloses refractories used for repairingthe damaged parts of hot iron runner of blast furnace urgently are provided to shorten the repairing time and extend the life of hot iron runner. The refractories are excellent in early strength and workability, comprising: fused alumina with different particle sizes such as 3-5mm(3-6wt.%], l-3mm(16-22wt.%), 0.5-lmm(14-18wt.%), and upto 0.074mm (15-17wt.%); 7-12wt.% ofSiC; 3-4wt.% of graphite powder; 5-7wt.% of carbon black for the increase of adhesion, 6-8wt.% of cokes powder(0.5-lmm); 3-4wt.% of silicon for the increase of strength; 13-14wt.% of tar for good workability; and 3wt.% of organic fiber, calculated by extrapolation.
[0010] CN119591424A discloses a repair slurry for a graphite crucible, that is characterized by being a two-component repair slurry and comprises a structural repair slurry and a surface layer repair slurry; the structural repair slurry comprises 50-60 parts by mass of a matrix, 10-15 parts by mass of a repair agent, 3-5 parts by mass of a binder and a proper amount of a solvent.
[0011] CN114031379A provides an aluminum-silicon high-temperature spray coating, which is prepared from the following raw materials: alumina, sintered mullite, corundum, andalusite, metal silicon powder, graphite or coke, and has the characteristics of low pollution, low risk, low cost, slag corrosion resistance, strong permeability resistance and the like. An aluminum-silicon high-temperature spray coating is characterized in that: the aluminum-silicon high-temperature spray coating is mainly composed of, by mass, 20-45% of alumina, 15-40% of sintered mullite, 10-30% of corundum, 0-10% of andalusite, 5-15% of metal silicon powder and 2-12% of graphite or coke; the purity ofthe metal silicon powder is more than 95 percent, and the granularity of the metal silicon powder is less than or equal to 0.044 mm.
[0012] KR19990018856A discloses a composition and a repair method of a repairing material which improves the service life of a solid bond with the base material and an increase in corrosion resistance when repairing the damage and dropping of the ladle I tundish internal refractories in contact with the molten steel, sintered or molten alumina, Ultrafine powdered alumina, magnesia, zircon, silica, bauxite, andrucite, mullite, from 80 to 97 parts by weight of one or two or more types of refractory raw materials, 2 to 15 parts by weight of a Na-Si binder, a curing regulator 0.5 It is composed of a repair material composed of ~5.0 parts by weight, and after the addition of water to the repairing material is a technique for repairing it by a patching method using iron or other tools to the damaged internal refractories.
[0013] CN101705326A discloses a repair method of a mixer furnace, comprising the following steps of: (1) preparing a high aluminum material from 80-90 parts of aluminums oxide and 9-20 parts of magnesium oxide which both have the granularity of less than or equal to 0.088 mm, preparing part ofthe high aluminum material into high aluminum aggregate with the granularity of 1-25 mm, wherein the repair material comprises the following raw materials in parts by weight: 10-20 parts of the high aluminum aggregate, 5-10 parts of the high aluminum material and 2-5 parts of the magnesium oxide; (2) mixing the repair material, then adding into a liquid containing glass water and water with the weight ratio of 2:3 to prepare a pulpy high aluminum casting material; (3) blowing a position needing repairing; (4) piling and repairing the high aluminum casting materialuniformly mixed by using a shovel to the position needing repairing; (5) spraying a mixture of a high aluminum spraying and repairing material and water by a spray gun so as to spray and repair each piled and repaired gap; and (6) opening a gas heater to bake the piling and repairing position for 2-3h.
[0014] Though the cited prior art discloses refractories for repairing the processing / manufacturing equipment, there is still a need for a refractory composition that provides superior thermal shock resistance and slag corrosion resistance compared to standard high-alumina mortars.
[0015] The embodiments of the present invention provides significant solutions to stated challenges of spun pipe manufacturing industries.OBJECTS OF THE PRESENT DISCLOSURE
[0016] Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as listed herein below.
[0017] It is an object of the present disclosure to provide the repairing and / or maintenance solutions in hot conditions as well as cold conditions for the processing and / or handling equipments of hot zone of Ductile Iron Spun pipe manufacturing process.
[0018] It is an object of the present disclosure to provide a refractory mixture for processing and / or handling equipments that is helpful in enhancement of the life of the equipment of the hot Zone.
[0019] It is yet another object of the present disclosure to provide a refractory mixture for the processing and / or handling equipments that is helpful in easier removal of slag.
[0020] It is yet another object of the present disclosure to provide a refractory mixture used in repairing and / or maintenance of processing and / or handling equipments that is recyclable and re-used in repairing and or maintenance operations that further reduce costs.
[0021] It is yet another object to provide disclosure to provide a refractory mixture for repairing the processing and / or handling equipments in either hot condition or cold condition by applying the mixture in the form of paste- brushing or spraying or gunning till damaged portion / or surface is completely leveled.SUMMARY
[0022] The embodiments of the present invention are related to the repairing and / or maintenance solutions for hot condition repair as well as cold condition repair for the processing and / or handling equipments of hot zone of Ductile Iron Spun pipe manufacturing process. The processing and / or handling equipments and / or its parts / accessories of DI Pipe Manufacturing setup include pouring spouts of Induction furnace, GF Convertor & Hopper, Transfer Ladles of Blast furnace, Induction Furnace & GF Convertor, Fall Chutes, Runners and moulds.
[0023] Further, the repair strategy shifts significantly depending on whether the system is operational or during a shutdown. Hot condition repairing cycle (hereinafter referred as "hot conditions”) are performed to minimize downtime, and in hot condition repairing cycle the refractory mixture is usually applied via spraying or patching. Cold condition repairing cycle (hereinafter referred as "cold conditions”) allow for more thorough surface preparation and thicker layering. Cold condition repairs often involves casting or manual trowelling. Layering is done progressively, ensuring each layer is sufficiently bonded to the substrate or the previous layer to prevent delamination.
[0024] The productivity of the Ductile Iron Pipe Manufacturing Process is significantly influenced by the efficient and effective working of processing and / or handling equipments and / or its parts / accessories to its potential lifespan. The preferential sequence of processing and / or handling equipments that affects the productivity of manufacturing process are as- 1. Moulds as it governs the final shape and dimension to the product,2. Fall Chutes ensures the specific flow of liquid metal and extent of spattering, 3. Runner defines the flow of molten metal in continuous Moulding Machine (CCM),4. Hoper defines the feeding of liquid metal to Fall Chute5. Spouts guide path of tap-out the liquid metal6. Transfer Ladles carry superheated liquid metalThe embodiments of present invention disclose the repairing and / or maintenance solutions for Fall Chute, Runner, Hoper, Spouts and Transfer Ladles.
[0025] In one of the embodiments, the repairing and / or maintenance solutions for Fall Chute, Runner and Hoper are preferably accomplished by layered coating of refractory mixture in hot conditions as well as cold conditions. The coating of refractory mixture is either water-based or alcohol-based mixture. The composition of the refractory mixture comprises a particulate aluminous refractory base material like Almunia Castable and Graphite Powder.
[0026] In one of the embodiments, the repairing and / or maintenance solutions for Runner is preferably accomplished by layered coating of refractory mixture in hot conditions as well as cold conditions. The coating of refractory mixture is either water-based or alcohol-based mixture. The composition of the refractory mixture comprises a particulate aluminous refractory base material like Almunia Castable, Graphite Powder and Fireclay.
[0027] In one of the embodiments, the repairing and / or maintenance solutions for Hoper and Transfer Ladles is preferably accomplished by layered coating of refractory mixture in hot conditions as well as cold conditions. The coating of refractory mixture is either water-based or alcohol-based mixture. The composition of the refractory mixture comprises a particulate aluminous refractory base material like Almunia Castable, Graphite Powder, Silica, Magnesia and Fireclay.
[0028] In accordance with the embodiments, the repairing and / or maintenance solutions for different spouts like Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout; Georg Fischer converter Ladle Spout is preferably accomplished by layered coating of refractory mixture in hot conditions as well as cold conditions. The coating of refractory mixture is either water-based or alcohol-based mixture. The composition of the refractory mixture comprises a particulate aluminous refractory base material like Alumina based Cement (ABC); Graphite powder; Lime (LM); Colloidal Silica (CS) or Silica Flour; Fire-Clay (FC); Bentonite (BN); Coal Dust (CD); Plaster of Paris (PoP); wherein either Coal Dust or Plaster of Paris can be used at a time.BRIEF DESCRIPTION OF DRAWINGS
[0029] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams are for illustration only, which thus is not a limitation of the present disclosure.Fig 1 lists different combinations of mixtures for repairing and / or maintenance solutions for Fall Chute, Runner, Hoper, and Transfer Ladles.Fig 2 lists different combinations, Mixture A to Mixture G, the refractory mixture prepared to repair different types of spouts.Fig 3 lists which kind of mixture among Mixture Ato Mixture G is suitable for Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout; Georg Fischer converter Ladle Spout.DETAILED DESCRIPTION
[0030] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the disclosure.
[0031] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
[0032] If the specification states that a component or feature "may”, "can”, "could” or "might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0033] As used in the description herein and throughout the description that follow, the meaning of "a,” "an,” and "the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in” includes "in” and "on” unless the context clearly dictates otherwise.
[0034] The use of "including” "comprising” or "having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "a” and "an” herein do not denote a limitation of quantity but rather denote the presence of at least one of the referenced items. Further, the use of terms "first” "second” and "third” and the like, herein does not denote any order, quantity, or importance, but rather are used to distinguish one element from another.
[0035] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and / or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the description herein.
[0036] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skilled in the art. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).The present disclosure relates to the repairing and / or maintenance solutions in hot conditions as well as cold conditions for the processing and / or handling equipments of hot zone of Ductile Iron Spun pipe manufacturing process. The refractory mixture for processing and / or handling equipments is helpful in enhancement of the life of the equipment of the hot Zone and is helpful in easier removal of slag. The refractory mixture is recyclable and re-used in repairing and or maintenance operations that further reduce costs. The refractory mixture can be applied in the form of paste- brushing or spraying or gunning till damagedportion / or surface is completely leveled. The embodiments of present invention disclose the repairing and / or maintenance solutions for Fall Chute, Runner, Hoper, Spouts and Transfer Ladles. Fig 1 lists different combinations of mixtures for repairing and / or maintenance solutions for Fall Chute, Runner, Hoper, and Transfer Ladles.
[0037] Fall Chute: Fall chute is an assembly between hopper and runner that undergoes frequent refractory damage, which leads to metal splashing and turbulence in metal flow. In DI Pipe manufacturing, the appropriate working condition of fall chute contributes significantly to productivity and rejection control.
[0038] In one of the embodiment of present invention, the repairing and / or maintenance of Fall Chute is preferably accomplished by layered coating of refractory mixture in hot conditions as well as cold conditions. The coating of refractory mixture is either water-based or alcohol-based mixture. The composition of the refractory mixture comprises a particulate aluminous refractory base material in proportion of 35% -65% w / w; and Graphite Powder in proportion of 35% -65% w / w.
[0039] In accordance with the preferred embodiment, the repairing and / or maintenance of Fall Chute is achieved using the particulate aluminous refractory base material includes Alumina Castable and the chemical analysis of Alumina Castable is A12O3.xH2O, having Alumina Content percentage by mass of 30%-91% of Alumina, 0.35%- 6.5% of Fe2O3, 8%- 45% of H20, 6%- 16% of CaO. The preferable particle size of aluminous refractory base material is in range of 0.01 to 3.0 mm. While in case of Graphite has 40%- 80% of Fixed Carbon, 3%- 25% of Volatile Matter, 0.5%- 15% Ash, 3%- 15% of Moisture. The preferable particle size of Graphite Powder is in the range of 0.01 to 0.1 mm. The preferred Baume scale for refractory mixture is greater than 90.
[0040] In accordance with the preferred embodiment, to develop instant strength in hot conditions, the repairing and / or maintenance of Fall Chute is preferably done with water-based mixture coating. This refractory coating cure minor to major damages by applying several coat layers. Further, the repairing and / or maintenance of Fall Chute is preferably done with alcohol-based mixture in cold conditions. For instant setting of coating of the refractory mixture, dry ice or ice and / or alcohol-based mixture is preferred. To achieve delayed setting of coats hot water-based mixtures are preferred.
[0041] Runners: defines the flow of molten metal in continuous Moulding Machine (CCM).
[0042] As per an embodiment of present invention, the repairing and / or maintenance of runners is preferably accomplished by layered coating of refractory mixture in hot conditions as well as cold conditions. The coating of refractory mixture is either water-based or alcohol-based mixture. The composition of the refractory mixture comprises a particulate aluminous refractory base material in proportion of 35% -65% w / w; and Graphite Powder in proportion of 35% -65% w / w to repair any minor or localized damage.
[0043] In accordance with the preferred embodiment, the repairing and / or maintenance of runners is achieved using the particulate aluminous refractory base material includes Alumina Castable and the chemical analysis of Alumina Castable is A12O3.xH2O, having Alumina Content percentage by mass of 30%-91% of Alumina, 0.35%- 6.5% of Fe2O3, 8%- 45% of H20, 6%- 16% of CaO. The preferable particle size of aluminous refractory base material is in range of 0.01 to 3.0 mm. While in case of Graphite has 40%- 80% of Fixed Carbon, 3%- 25% of Volatile Matter, 0.5%- 15% Ash, 3%- 15% of Moisture. The preferable particle size of Graphite Powder is in the range of 0.01 to 0.1 mm. The preferred Baume scale for refractory mixture is greater than 90.
[0044] In accordance with the preferred embodiment, to repair major damage in runners, the composition of the refractory mixture is altered by including an additional component like fireclay in proportion of 15%-45% w / w, in combination with a particulate aluminous refractory base material in proportion of 35%-65% w / w and Graphite Powder in proportion of 35%-65% w / w. The inclusion of fireclay can increase the life of runners. The preferable particle size of fireclay particles is in range of 0.1 mm to 0.8 mm. The commercial grade of Fireclay available on the market is preferred in this embodiment. The preferred Baume scale for the refractory mixture is not less than & equal to 30 and not greater than & equal to 70. In case of runners for the pipe size above DN 400, content and purity of alumina mixture is kept on the higher side.
[0045] In the economic perspective, the remains of the refractory mixture for Fall-Chute repairing, and / or Runner repairing, and combination thereof can be used. The coating of the refractory mixture works as a sacrificial layer which maintains uniformity and cleanliness.
[0046] Hopper: The Hopper works as a fixed quantity reservoir of the liquid metal. The thickness and weight of the pipe is influenced by the cleanliness and volume of the Hopper. The slag accumulates on the top surface and mouth of the Hopper, which has to be removed mechanically and frequently that cause the localized damages. If the slag not removed, metal and pipe quality is compromised. Further it lowers the metal temperature which lowers the metal fluidity. Hence frequent repairing of the top and mouth of the Hopper is required.
[0047] The embodiment of the present invention discloses the repairing of the top and mouth of the Hopper by coating of water-based mixture when hopper is in hot condition or by alcohol-based mixture when hopper is in cold condition. In accordance with the preferred embodiment, to repair and / or maintain minor damage in the hopper, the refractory mixture comprises of a particulate aluminous refractory base material in proportion of 35%-65% w / w; and GraphitePowder in proportion of 35%-65% w / w, to repair any minor damage. The particulate aluminous refractory base material includes Alumina Castable and the chemical analysis of Alumina Castable is A12O3.xH2O, having Alumina Content percentage by mass of 30%- 91% of Alumina, 0.35%- 6.5% of FezCh, 8%- 45% of HzO, 6%- 16% of CaO. The preferable particle size of aluminous refractory base material is in range of 0.01 to 3.0 mm. While in case of Graphite has 40%- 80% of Fixed Carbon, 3%- 25% of Volatile Matter, 0.5%- 15% Ash, 3%- 15% of Moisture. The preferable particle size of Graphite Powder is in the range of 0.01 to 0.1 mm. The preferred Baume scale for refractory mixture is greater than 90.
[0048] In accordance with the preferred embodiment, to repair and / or maintain major damage in the hopper, the refractory mixture comprises of a particulate aluminous refractory base material (Alumina Castable) of 35%-65% w / w; Graphite Powder of 35%-65% w / w; different proportions of Silica of 15%-50% w / w, Magnesia of 25%- 50% w / w and Fire-clay of 15%- 45% w / w. The preferable particle size for Silica (SiCh) is in range of 0.01 to 0.80mm, for Magnesia (MgO) in range of 0.01- 0.15mm and fireclay in range of 0.01-0.80 mm. By incorporating Magnesia with a controlled particle size of 0.01-0.15 mm into an Alumina-Silica system, the composition facilitates in-situ spinel formation. This reaction generates a controlled volumetric expansion that compensates for the drying shrinkage of the binder phase, ensuring a positive interference fit between the repair mass and the host structure. Furthermore, the specific granulometric range of Silica and fireclay (0.01-0.80 mm) creates a functionally graded matrix. The ultra-fine fraction (0.05 mm) acts as a micro-filler to reduce permeability, while the coarser fraction provides structural bridging. This synergistic combination provides superior thermal shock resistance and slag corrosion resistance compared to standard high-alumina mortars.
[0049] The local repairing of hopper results in better metal temperature, excellent metal fluidity, Lower temperature loss, fix capacity of the Hopper,laminar flow of liquid metal, less damage to fall chute, uniform filling of mould, higher production, Lower rejection of pipe. The present composition overcomes the inherent limitations of conventional repair mixes, specifically the tendency for shrinkage-induced delamination and high porosity.
[0050] Transfer Ladles in the present embodiment of present invention, the term "Transfer Ladles” is referred as Blast furnace transfer ladle, induction furnace to converter transfer ladle or magnesium treated metal transfer ladle. In all kind of ladles, slag generation, slag floating, and slag accumulation happens continuously. This affects the top portion and tapping side of ladles. The continuous slag accumulation results in decrease ladles volume, higher temperature loss, increased metal loss, turbulence in flow, effects desired residual magnesium, increased magnesium consumption, increased silicon losses, increased carbon losses, deceased metal fluidity, main cause of Hopper and fall chute damage.
[0051] In accordance with the preferred embodiment, the repairing and / or maintenance of Transfer Ladle is accomplished in both hot conditions as well as cold conditions, preferably by layered coating of refractory mixture of Silica, Magnesia, Fireclay in the basic mixture of Alumina Castable with Graphite to repair localized damage. The composition of the refractory mixture comprises a particulate Alumina Castable of 35% - 65% w / w; Graphite Powder of 35% - 65% w / w, Silica of 15%- 50% w / w, Magnesia of 25%- 50% w / w, and Fire-clay of 15%-45% w / w. The preferable particle size for Silica (SiOz) is in range of 0.01 to 0.80mm, for Magnesia (MgO) in range of 0.01- 0.15mm and fireclay in range of (0.01-0.80 mm). The preferred Baume scale for refractory mixture is greater than 90.
[0052] Spouts: In embodiment of present invention, the term "spout” referred as spout of induction furnace, blast furnace ladle, Magnesium Convertor ladle and transfer ladle. In general, the quantity of metal flow through the spouts varies from 2.5 MT (Convertor and ladle) to 20 MT (Induction furnace and ladle). Thedamage in spouts disturbs the uniform discharge of the metal and causes metal splashing. The disturbance in discharge further causes accidents and compromised metal quality, while due to metal splashing, there is metal loss and chances of fatal accidents too.
[0053] In accordance with the embodiments, the details of composition of refractory mixture for repairing different spouts in accordance with the present invention are detailed mentioned in Table-1 (Fig 1) and Table 2 (Fig 2). Fig 1 lists different combinations, Mixture A to Mixture G, the refractory mixture prepared to repair different types of spouts. Fig 2 lists which kind of mixture among Mixture A to Mixture G is suitable for Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout; Georg Fischer converter Ladle Spout.
[0054] In one of the embodiments, the repairing and / or maintenance of Blast Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout by coating of water-based mixture when spout is in hot condition or by alcohol-based mixture when spout is in cold condition. In accordance with the preferred embodiment, to repair and / or maintain the damage in the Blast Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout, the refractory mixture (Mixture A) used comprises of a particulate aluminous refractory base material in proportion of 65%-85% w / w; and Graphite Powder in proportion of 15%-35% w / w. The particulate aluminous refractory base material includes Alumina based Cement (ABC).
[0055] In one of the embodiments, the repairing and / or maintenance of Blast Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout by coating of water-based mixture when spout is in hot condition or by alcohol-based mixture when spout is in cold condition. In accordance with the preferred embodiment, to repair and / or maintain thedamage in the Blast Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout, the refractory mixture (Mixture B) used comprises of a particulate aluminous refractory base material in proportion of 40%-65% w / w; and Graphite Powder in proportion of 35%-60% w / w. The particulate aluminous refractory base material includes Alumina based Cement (ABC).
[0056] In one of the embodiments, the repairing and / or maintenance of Blast Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout by coating of water-based mixture when spout is in hot condition or by alcohol-based mixture when spout is in cold condition. In accordance with the preferred embodiment, to repair and / or maintain the damage in the Blast Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout, the refractory mixture (Mixture C) used comprises of a particulate aluminous refractory base material in proportion of 50% w / w (average proportion 45%-55% w / w); and Graphite Powder in proportion of 50% w / w. The particulate aluminous refractory base material includes Alumina based Cement (ABC).
[0057] In one of the embodiments, the repairing and / or maintenance of Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout; Georg Fischer converter Ladle Spout by coating of water-based mixture when spout is in hot condition or by alcohol-based mixture when spout is in cold condition. In accordance with the preferred embodiment, to repair and / or maintain the damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout; Georg Fischer converter Ladle Spout, the refractory mixture (Mixture D) used comprises of a particulate aluminous refractory base material in proportion of 15%-50% w / w; Graphite Powder in proportion of 15%-85% w / w; and Fire-Clay of 30%- 60% w / w. The particulate aluminous refractory base material includes Alumina based Cement (ABC).
[0058] In one of the embodiments, the repairing and / or maintenance of Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Georg Fischer converter Ladle Spout by coating of water-based mixture when spout is in hot condition or by alcohol-based mixture when spout is in cold condition. In accordance with the preferred embodiment, to repair and / or maintain the damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Georg Fischer converter Ladle Spout, the refractory mixture (Mixture E) used comprises of a particulate aluminous refractory base material in proportion of 7%-15% w / w; Colloidal Silica in proportion of 5%-10% w / w; Fire-Clay of 35%- 45% w / w; and Lime of 15%-35% w / w. The particulate aluminous refractory base material includes Alumina based Cement (ABC). The particulate aluminous refractory base material includes Alumina based Cement (ABC).
[0059] In one of the embodiments, the repairing and / or maintenance of Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout by coating of water-based mixture when spout is in hot condition or by alcohol-based mixture when spout is in cold condition. In accordance with the preferred embodiment, to repair and / or maintain the damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout, the refractory mixture (Mixture F) used comprises of Lime of 15%-35% w / w; Colloidal Silica of 10%-15% w / w; Fire-Clay of 10%- 25% w / w; Bentonite of 3%-25% w / w; and Coal Dust of 45%-60% w / w.
[0060] In one of the embodiments, the repairing and / or maintenance of Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout by coating of water-based mixture when spout is in hot condition or by alcohol-based mixture when spout is in cold condition. In accordance with thepreferred embodiment, to repair and / or maintain the damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout, the refractory mixture (Mixture F) used comprises of Lime of 15%-35% w / w; Colloidal Silica of 10%-15% w / w; Fire-Clay of 10%- 25% w / w; Bentonite of 3%-25% w / w; and Plaster of Paris (PoP) of 45%-60% w / w.
[0061] In one of the embodiments, the repairing and / or maintenance of Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout by coating of water-based mixture when spout is in hot condition or by alcohol-based mixture when spout is in cold condition. In accordance with the preferred embodiment, to repair and / or maintain the damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout, the refractory mixture (Mixture G) used comprises of comprises of Alumina based Cement of 5%- 25% w / w, Lime of 5%-20% w / w; Colloidal Silica of 25%-45% w / w; Fire-Clay of 10%- 45% w / w; Bentonite of 10%-35% w / w; and Coal Dust of 35%-65% w / w.
[0062] In one of the embodiments, the repairing and / or maintenance of Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout by coating of water-based mixture when spout is in hot condition or by alcohol-based mixture when spout is in cold condition. In accordance with the preferred embodiment, to repair and / or maintain the damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout, the refractory mixture (Mixture G) used comprises of Alumina based Cement of 5%- 25% w / w, Lime of 5%-20% w / w; Colloidal Silica of 25%-45% w / w; Fire-Clay of 10%- 45% w / w; Bentonite of 10%-35% w / w; and Plaster of Paris (PoP) of 35%-65% w / w.
[0063] The embodiments of the invention are prone to numerous modifications and variations, all of which are within the scope of the same inventive concept. Further, the material, composition, and devices used may of course bereplaced / altered with other technically equivalent ones; the steps may furthermore be performed in a different sequence.ADVANTAGES OF THE INVENTION
[0064] The present invention provides the combination of High Alumina Castable (the structural backbone), and Graphite Powder (the functional additive) creates a specific set of Synergistic Advantages. Pure High Alumina is extremely hard but can be brittle. When a Fall Chute is subjected to rapid temperature changes, pure alumina tends to crack or fall-off. Graphite has high thermal conductivity and a low coefficient of thermal expansion. When mixed, the graphite particles act as microscopic shock absorbers. They conduct heat away from the surface quickly, preventing the formation of steep temperature gradients that cause cracking. This significantly extends the life of the coating during Hot Condition Repair cycling.
[0065] Molten metal and slag love to stick to oxide ceramics (like Alumina). This leads to "build-up" or clogging in the chute, requiring frequent mechanical cleaning (which damages the lining). The presence of graphite on the surface creates a high contact angle for molten slag. The slag creates beads and rolls off rather than wetting the surface and penetrating the pores. This keeps the chute clean and maintains flow.
[0066] Even though the Alumina provides the hardness to stop deep gouging, the Graphite reduces the surface coefficient of friction. This allows falling material to slide over the coating with less resistance, reducing the shearing force that typically tears coatings off the wall. Because the metal cannot wet the graphite, it cannot enter these pores. The coating remains a surface barrier rather than becoming saturated with metal.
[0067] The inclusion of Silica, Magnesia, and Fireclay to the base Alumina-Graphite mixture transforms it from a simple surface coating into a complexpatching compound designed for structural repair. By using all three with the specific particle sizes Silica 0.01-0.80mm, Magnesia 0.01-0.15mm, fireclay 0.01-0.80mm, the mixture can achieve Maximum Packing Density. The fine Magnesia and Silica particles fit into the spaces between the larger Alumina / Fire-clay grains. A denser mix means there are fewer pathways for molten slag or gas to penetrate the patch. Hence, the repair is less permeable and stronger than the original lining, preventing the localized damage from recurring in the same spot.
Claims
CLAIMS:I / We claim:
1. A refractory mixture for repairing and / or maintenance of processing and / or handling equipments of hot zone of Ductile Iron Spun pipe manufacturing unit, such refractory mixture comprising:particulate aluminous refractory base material of 35%-65%w / w; Graphite Powder of 35%-65% w / w;Silica (SiOz) of 0- 50% w / w;Magnesia (MgO) of 0-50% w / w; andFire-clay of 0-45% w / w.
2. The refractory mixture as claimed in claim 1 is water-based mixture.
3. The refractory mixture as claimed in claim 1 is alcohol-based mixture.
4. The refractory mixture as claimed in claim 1 can be applied in hot condition repairing cycle and cold condition repairing cycle.
5. The refractory mixture as claimed in claim 1 wherein the aluminous refractory base material is Alumina Castable.
6. The refractory mixture as claimed in claim 1 wherein particle size of aluminous refractory base material is 0.01 to 3.0 mm.
7. The refractory mixture as claimed in claim 1 wherein particle size of Graphite Powder is 0.01 to 0.1 mm.
8. The refractory mixture as claimed in claim 1 wherein particle size of Silica (SiOz) is 0.01 to 0.80mm.
9. The refractory mixture as claimed in claim 1 wherein particle size of Magnesia (MgO) is 0.01- 0.15mm.
10. The refractory mixture as claimed in claim 1 wherein particle size of fireclay is 0.01-0.80 mm.
11. The refractory mixture as claimed in claim 1 wherein the processing and / or handling equipments include Fall Chute, Runner, Hoper, Transfer Ladles and the like.
12. The refractory mixture as claimed in claim 11, wherein for repairing and / or maintenance of localized damage or a major damage in the Fall Chute, the refractory mixture includes particulate Alumina Castable of 35%-65%w / w; Graphite Powder of 35%-65% w / w.
13. The refractory mixture as claimed in claim 11, wherein for repairing and / or maintenance of localized damage or minor damage in the runners, the refractory mixture includes particulate Alumina Castable 35% -65% w / w; and Graphite Powder 35% -65% w / w.
14. The refractory mixture as claimed in claim 11, wherein for repairing and / or maintenance of major damage in the runners, the refractory mixture includes Particulate Alumina Castable 35%-65% w / w; Graphite Powder 35%-65% w / w and fireclay 15%-45% w / w.
15. The refractory mixture as claimed in claim 11, wherein for repairing and / or maintenance of localized damage or minor damage in the hopper, the refractory mixture includes particulate Alumina Castable 35% -65% w / w; and Graphite Powder 35% -65% w / w.
16. The refractory mixture as claimed in claim 11, wherein for repairing and / or maintenance of major damage in the hopper, the refractory mixture includes particulate Alumina Castable 35%-65% w / w; Graphite Powder 35%-65% w / w; Silica 15%-50% w / w; Magnesia 25%- 50% w / w; and Fire-clay 15%- 45% w / w.
17. The refractory mixture as claimed in claim 11, wherein for repairing and / or maintenance of localized damage or a major damage in the Transfer Ladles, the refractory mixture includes particulate AluminaCastable 35%-65% w / w; Graphite Powder 35%-65% w / w; Silica 15%- 50% w / w; Magnesia 25%- 50% w / w; and Fire-clay 15%- 45% w / w.
18. A refractory mixture for repairing and / or maintenance of processing and / or handling equipments of hot zone of Ductile Iron Spun pipe manufacturing unit, such refractory mixture comprising:particulate aluminous refractory base material of 15% -85% w / w; Graphite powder of 15% -85% w / w; andFire-Clay (FC) of 0-60% w / w;19. The refractory mixture as claimed in claim 18 is water-based mixture.
20. The refractory mixture as claimed in claim 18 is alcohol-based mixture.
21. The refractory mixture as claimed in claim 18 can be applied in hot condition repairing cycle and cold condition repairing cycle.
22. The refractory mixture as claimed in claim 18 wherein the aluminous refractory base material is Alumina based Cement (ABC).
23. The refractory mixture as claimed in claim 18 wherein the processing and / or handling equipments include Spouts.
24. The refractory mixture as claimed in claim 23 wherein the Spouts include Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout; Georg Fischer converter Ladle Spout and the like.
25. The refractory mixture as claimed in claim 24 wherein for repairing and / or maintenance of damage in the Blast Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout, the refractory mixture includes Alumina based Cement (ABC) of 65%-85% w / w; and Graphite Powder of 15%-35% w / w.
26. The refractory mixture as claimed in claim 24 wherein for repairing and / or maintenance of damage in the Blast Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischerconverter Spout, the refractory mixture includes Alumina based Cement (ABC) of 40%-65% w / w; and Graphite Powder of 35%-60% w / w.
27. The refractory mixture as claimed in claim 24 wherein for repairing and / or maintenance of damage in the Blast Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout, the refractory mixture includes Alumina based Cement (ABC) of 50% w / w (average proportion 45%-55% w / w); and Graphite Powder of 50%w / w.
28. The refractory mixture as claimed in claim 24 wherein for repairing and / or maintenance of damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout; Georg Fischer converter Ladle Spout, the refractory mixture includes Alumina based Cement (ABC) of 15%-50% w / w; Graphite Powder of 15%-85%w / w; and Fire-Clay of 30%- 60% w / w.
29. A refractory mixture for repairing and / or maintenance of processing and / or handling equipments of hot zone of Ductile Iron Spun pipe manufacturing unit, such refractory mixture comprising:Lime (LM) of 5% -35% w / w;Fire-Clay (FC) of 10-45% w / w;Colloidal Silica (CS) or Silica Flour 5% -45% w / w;Bentonite (BN) of 0-35% w / w;particulate aluminous refractory base material of 0-25% w / w; and Coal Dust (CD) of 0-65% w / w or Plaster of Paris (PoP) of 0-65% w / w.
30. The refractory mixture as claimed in claim 29 is water-based mixture.
31. The refractory mixture as claimed in claim 29 is alcohol-based mixture.
32. The refractory mixture as claimed in claim 29 can be applied in hot condition repairing cycle and cold condition repairing cycle.
33. The refractory mixture as claimed in claim 29 wherein the aluminous refractory base material is Alumina based Cement (ABC).
34. The refractory mixture as claimed in claim 29 wherein the processing and / or handling equipments include Spouts.
35. The refractory mixture as claimed in claim 34 wherein the Spouts include Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Induction Furnace -Georg Fischer converter Spout; Georg Fischer converter Ladle Spout and the like.
36. The refractory mixture as claimed in claim 35 wherein for repairing and / or maintenance of damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Blast Furnace - Induction Furnace Spout; Georg Fischer converter Ladle Spout, the refractory mixture includes Alumina based Cement (ABC) of 7%-15% w / w; Colloidal Silica of 05%- 10% w / w; Fire-Clay of 35%- 45% w / w; and Lime of 15%-35% w / w.
37. The refractory mixture as claimed in claim 35 wherein for repairing and / or maintenance of damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout, the refractory mixture includes Lime of 15%-35% w / w; Colloidal Silica of 10%-15% w / w; Fire-Clay of 10%- 25% w / w; Bentonite of 3%-25% w / w; and Coal Dust of 45%-60% w / w.
38. The refractory mixture as claimed in claim 35 wherein for repairing and / or maintenance of damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout, the refractory mixture includes Lime of 15%-35% w / w; Colloidal Silica of 10%-15% w / w; Fire-Clay of 10%- 25% w / w; Bentonite of 3%-25% w / w; and Plaster of Paris (PoP)of 45%-60% w / w.
39. The refractory mixture as claimed in claim 35 wherein for repairing and / or maintenance of damage in the Blast Furnace Ladle Spout;Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout, the refractory mixture includes Alumina based Cement of 5%- 25% w / w, Lime of 5%-20% w / w; Colloidal Silica of 25%-45% w / w; Fire-Clay of 10%- 45% w / w; Bentonite of 10%-35% w / w; and Coal Dust of 35%-65% w / w.
40. The refractory mixture as claimed in claim 35 wherein for repairing and / or maintenance of damage in the Blast Furnace Ladle Spout; Induction Furnace Ladle Spout; Georg Fischer converter Ladle Spout, the refractory mixture includes Alumina based Cement of 5%- 25% w / w, Lime of 5%-20% w / w; Colloidal Silica of 25%-45% w / w; Fire-Clay of 10%- 45% w / w; Bentonite of 10%-35% w / w; and Plaster of Paris (PoP) of 35%-65% w / w.