FLUXING AGENT

TECHNICAL FIELD
[0001] The present disclosure relates to the field of steel manufacturing. More particularly, the present disclosure relates to a method of making a fluxing agent to be used in steel manufacturing.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Basic oxygen steelmaking (BOS), also known as Linz–Donawitz-steelmaking or the oxygen converter process is a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing oxygen through molten pig iron lowers the carbon content of the alloy and changes it into low-carbon steel. However, in the Linz–Donawitz-steelmaking process, the blowing of the oxygen through the molten pig iron results in dissolving of the oxygen into an output product and becoming detrimental to product properties.
[0004] Therefore, in Linz-Donawitz (LD) stage 1, silicon and manganese are mainly used for removing dissolved oxygen. Slag formed in Si/Mn killed steel is solid due to formation of dicalcium silicate (MP 2040 °C) slag. In absence of liquid slag, arcing at ladle furnace results in noise and dust pollution. Enriching Si-Mn slags with Alumina lowers its melting point below steelmaking temperatures. However, in the open cast technology for producing billet, the proposed enrichment is not suitable as clogs metering nozzles and finally aborting the production.
[0005] In the last few years, several synthetic slags have been tried out to counter the abovementioned problems. Fluorspar is commonly used as fluxing agent. However, this corrodes ladle refractories and generates environmentally and physically harmful Carbon tetrafluoride, Silicon tetrafluoride and releases fluorine. Also, such Si killed ladle slag when cooled undergo phase transformation (alpha to Beta phase) with volume expansion. It crumbles during cooling causing dust pollution.

OBJECTS OF THE DISCLOSURE
[0006] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0007] It is a general object of the present disclosure to provide a fluxing agent, to fluidise slag so that while arcing it may not produce noise.
[0008] It is another object of the present disclosure to provide a fluxing agent, using which can eliminate use of harmful fluidizer that produces harmful gases.
[0009] These and other objects and advantages of the present invention will be apparent to those killed in the art after a consideration of the following detailed description in which a preferred form of the present invention is illustrated.

SUMMARY
[0010] This summary is provided to introduce concepts related to a method of making a fluxing agent to be used in steel manufacturing. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0011] In an embodiment, the present disclosure relates to a method of making a fluxing agent for steel manufacturing. The method includes mixing a ladle furnace slag with lime and dolomite, where the ladle furnace slag being 60-70 % by weight, the lime being 20-30% by weight, and the dolomite being 5-10% by weight.
[0012] In an aspect, the ladle furnace slag comprises the following composition by weight:
58.19 % < Calcium Oxide (CaO) < 60.4 %,
3.3 % < Silicon Dioxide (SiO2) < 5.24 %,
2.25 % < Magnesium Oxide (MgO) < 3.27 %,
26.26 % < Aluminum Oxide (Al2O3) < 31.87 %,
0.055 % < Titanium Dioxide (TiO2) < 0.146 %,
0.59 % < Iron Oxide (FeO) < 1.89 %, where 70-80 % FeO and 20-30 % Fe2O3,
0.043 % < Sulphur < 0.183 %,
0.342 % Manganese Oxide (MnO) < 2.982 %,
0.003 % < Chromium Trioxide (Cr2O3) < 0.012 %,
0.031 % < Phosphorus Pentoxide (P2O5) < 0.146 %, and
remainder being unavoidable impurities.
[0013] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments.

DETAILED DESCRIPTION
[0014] The following is a detailed description of embodiments of the disclosure. 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 appended claims.
[0015] As used in the description herein and throughout the claims 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.
[0016] As mentioned in the background section, ladle furnace slags are generally by product compounds generated by steel manufacturing and processing. The term “slag” encompasses a wide variety of by product materials, typically including a large portion of the non-metallic by products of ferrous metal and/or steel manufacturing and processing.
[0017] Generally, slagging agents, or flux materials, are added to furnaces to strip impurities from the molten iron ore, steel scrap, iron and/or steel feed stock during processing. In accordance with the present disclosure, the fluxing agents/ materials are lime (CaO) and dolomite (CaCO3.MgCO3) which are added to the ladle furnace slag. In an aspect, the ladle furnace slag being 60-70 % by weight, the lime being 20-30% by weight, and the dolomite being 5-10% by weight.
[0018] In an aspect, the ladle furnace slag comprises the following composition by weight:
58.19 % < Calcium Oxide (CaO) < 60.4 %,
3.3 % < Silicon Dioxide (SiO2) < 5.24 %,
2.25 % < Magnesium Oxide (MgO) < 3.27 %,
26.26 % < Aluminum Oxide (Al2O3) < 31.87 %,
0.055 % < Titanium Dioxide (TiO2) < 0.146 %,
0.59 % < Iron Oxide (FeO) < 1.89 %, where 70-80 % FeO and 20-30 % Fe2O3,
0.043 % < Sulphur < 0.183 %,
0.342 % Manganese Oxide (MnO) < 2.982 %,
0.003 % < Chromium Trioxide (Cr2O3) < 0.012 %,
0.031 % < Phosphorus Pentoxide (P2O5) < 0.146 %, and
remainder being unavoidable impurities.
[0019] In operation, steel slags are formed during the further processing of pig iron and other steel materials in steel-making furnaces. Typical steel furnaces include basic oxygen process furnaces (BOF), open hearth furnaces (OHF), and electric arc furnaces (EAF). Most of the steel is nowadys made in integrated steel plants using a version of the basic oxygen process or in specialty steel plants that use an electric arc furnace process. In an exemplary basic oxygen process, hot liquid blast furnace metal, scrap, and fluxes are charged to a converter (furnace). A lance is lowered into the converter and high-pressure oxygen is injected. The oxygen combines with and removes the impurities in the charge. These impurities consist of carbon as gaseous carbon monoxide, and silicon, manganese, phosphorus and some iron as liquid oxides, which combine with a fluxing agent/material including lime CaO) and dolomite (CaCO3.MgCO3) to form the steel slag. At the end of the refining operation, the liquid steel is poured into a ladle while the steel slag is retained in the vessel and subsequently tapped into a separate slag pot.
[0020] Thus, the present disclsoure provides a fluxing agent/material which eliminates use of harmful fluidizer that produces harmful gases.
[0021] Furthermore, those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[0022] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0023] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0024] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

We claim:

1. A method of making a fluxing agent for steel manufacturing, the method comprising:
mixing a ladle furnace slag with lime and dolomite, where the ladle furnace slag being 60-70 % by weight, the lime being 20-30% by weight, and the dolomite being 5-10% by weight.
2. The method as claimed in claim 1, wherein the ladle furnace slag comprises the following composition by weight:
58.19 % < Calcium Oxide (CaO) < 60.4 %,
3.3 % < Silicon Dioxide (SiO2) < 5.24 %,
2.25 % < Magnesium Oxide (MgO) < 3.27 %,
26.26 % < Aluminum Oxide (Al2O3) < 31.87 %,
0.055 % < Titanium Dioxide (TiO2) < 0.146 %,
0.59 % < Iron Oxide (FeO) < 1.89 %, where 70-80 % FeO and 20-30 % Fe2O3,
0.043 % < Sulphur < 0.183 %,
0.342 % Manganese Oxide (MnO) < 2.982 %,
0.003 % < Chromium Trioxide (Cr2O3) < 0.012 %,
0.031 % < Phosphorus Pentoxide (P2O5) < 0.146 %, and
remainder being unavoidable impurities.