Reagent for hot metal desulphurization, methods and applications thereof

Abstract

The present disclosure provides a desulphurization reagent comprising about 12-18% w / w of CaSi, about 4-8% w / w of slag conditioner and about 1-5% w / w of melt agitator or gassifying agent optionally along with further components such as but 10 not limited to calcium bearing compound(s), flow aid(s) and deoxidizer(s). Said reagent of the present disclosure facilitates removal of sulphur from hot metal while simultaneously reducing FeO content in the process slag. Corresponding method of preparation, and application or use of said reagent in desulphurization of hot metal (HMDS) during steel production are also provided. The present desulphurization 15 reagent eliminates reliance on expensive and harmful reagents such as magnesium. The present desulphurization reagent has several advantages over conventional desulphurization reagents with respect to the efficiency of the desulphurization process and the reduction of FeO content in the slag. Overall, the reagent helps reduce costs associated with the desulphurization process. 20

Description

[0001] “REAGENT FOR HOT METAL DESULPHURIZATION, METHODS

[0002] AND APPLICATIONS THEREOF”

[0003] TECHNICAL FIELD

[0004] The present disclosure is relevant to the field of metallurgy. Particularly, the present disclosure relates to desulphurization of hot metal. The present disclosure, more particularly, is directed towards a dual objective of effective desulphurization of hot metal and simultaneous reduction of iron(II) oxide (FeO) content in the slag. The present disclosure provides a desulphurization reagent comprising CaSi along with other components such as but not limited to slag conditioner and melt agitator at specific concentration ranges, a method of preparation of said desulphurization reagent, and application or use of said desulphurization reagent for desulphurization of hot metal (HMDS) during production of steel.

[0005] BACKGROUND OF THE DISCLOSURE

[0006] During steel making process, removal of sulphur from hot metal is called desulphurization of hot metal (HMDS). Sulphur is a desirable element in steel when good machinability is required from the steel product. However, it is an unwanted element / impurity in most of the applications of steel due to the following reasons: sulphur affects both internal and surface quality of steel. sulphur contributes to the steel brittleness and when it exists in sulphide phase, it acts as a stress raiser in steel products. sulphur forms undesirable sulphides which promote granular weakness and cracks in steel during solidification. sulphur has adverse effect on the mechanical properties of steel. sulphur lowers the melting point, intergranular strength and cohesion of steel.

[0007] Hence, it is essential to remove sulphur from (desulphurize) hot metal before primary steel making. While a number of technologies have been developed for the external desulphurization of hot metal, a commonly used desulphurizing process is the deep injection of desulphurizing reagent in the hot metal. This is also known as dip lance process which is a reliable method for desulphurization of hot metal. Said method consists of pneumatic injection of desulphurization reagent into the hot metal with high dosing precision via a dispensing vessel and a refractory lined lance.

[0008] Commonly used desulphurization reagents for this process include lime, calcium carbide, magnesium etc. which remove sulphur in the hot metal by chemical reaction and transfer it to slag that is usually removed immediately after completion of the injection process. One of the common methods of slag removal is to tilt the ladle and rake the slag off the ladle with the help of a slag raking machine.

[0009] However, there are issues with respect to the currently employed desulphurizing reagents. For instance, most of the currently employed desulphurization reagents are very expensive. Particularly, magnesium that is routinely employed in these reagents is both hazardous as well as expensive. In addition, its availability is restricted to a limited number of countries. Further, another drawback commonly seen in the use of these reagents is the high FeO content in the slag arising from the desulphurization process, leading to lower process economy.

[0010] Therefore, there is an immense need to develop an alternate, simple, and more importantly an economical / cost effective and environment friendly / less hazardous desulphurization reagent for effective removal of sulphur from hot metal during steel making process. The present disclosure addresses this need.

[0011] SUMMARY OF THE DISCLOSURE

[0012] Addressing the aforesaid need in the art, the present disclosure provides a desulphurization reagent comprising about 12-18% w / w of CaSi, about 4-8% w / w of a slag conditioner and about 1-5% w / w of a melt agitator or gassifying agent. In some embodiments, the desulphurization reagent further comprises an additional component selected from a group comprising a calcium bearing compound, a flow aid or fluidizer and a deoxidizer or any combination thereof.

[0013] In some embodiments, the slag conditioner is selected from a group comprising a sodium based compound, an aluminium based compound and a fluorine -based compound or any combination thereof.

[0014] In some embodiments, the slag conditioner is selected from a group comprising cryolite, alumina, fluorspar, bauxite, soda ash and borax or any combination thereof.

[0015] In some embodiments, the melt agitator or gassifying agent is selected from a group comprising coal, limestone, dolomite and gilsonite or any combination thereof.

[0016] In some embodiments, calcium bearing compound is selected from a group comprising lime, calcined lime, limestone and calcium chloride or any combination thereof and / or is present at a concentration ranging from about 70-80% w / w.

[0017] In some embodiments, the flow aid or fluidizer is selected from silicone oil and coal or a combination thereof, preferably silicone oil, and / or is present at a concentration ranging from about 0.05-5% w / w.

[0018] In some embodiments, the deoxidizer is selected from a group comprising metallic aluminium, coal and coke or any combination thereof, preferably metallic aluminium and is present at a concentration ranging from about 1-10% w / w.

[0019] The present disclosure further provides a method for preparing the desulphurization reagent defined above, the method comprising: mixing about 12-18% w / w of the CaSi, about 4-8% w / w of the slag conditioner, about 1-5% w / w of the melt agitator or gassifying agent and optionally, the calcium bearing compound, the flow aid or fluidizer and / or the deoxidizer to obtain the desulphurization reagent.

[0020] In some embodiments, the mixing step comprises mixing the components, crushing, grinding, pulverising, or any combination of said techniques; and wherein said mixing is carried out by employing a rod mill, ball mill, blender, crusher, grinder, pulverizer, or any combination thereof.

[0021] Further provided herein is a process of desulphurization of hot metal during production of steel, the process comprising contacting the desulphurization reagent as defined above with the hot metal to obtain desulphurized hot metal and sulfur rich slag.

[0022] In some embodiments, the process also results in the simultaneous reduction of FeO content in the slag along with the removal of sulphur from the hot metal.

[0023] In some embodiments, the desulphurization reagent is contacted with the hot metal for desulphurization through one or more of mono-injection process, co-injection process, multi -injection, pour-over process, ladle top addition or ladle bottom addition.

[0024] In some embodiments, the co-injection process comprises co-injecting Reagent A comprising about 20% to about 25% w / w of CaSi, about 1% to about 5% w / w of a melt agitator or gassifying agent and about 4% to about 10 % w / w of a slag conditioner and Reagent B comprising about 90% to about 97% w / w of calcium bearing compound and about 1% to about 10% w / w of slag conditioner, such that the final reagent contacted with the hot metal is the desulphurization reagent as claimed in any one of claims 1-9.

[0025] In some embodiments, the Reagent A as defined above further comprises about 60% to about 75% w / w of a calcium bearing compound and about 0.05% to about 0.5% w / w of a flow aid or fluidizer.

[0026] In some embodiments, the desulphurization reagent is contacted with the hot metal at a ratio of about 9: 10000 to about 1: 100 by weight; and / or wherein the desulphurization reagent is contacted with the hot metal at a temperature ranging from about 1275°C to about 1450 °C.

[0027] In some embodiments, the desulphurization reagent is contacted with the hot metal at a flow rate of about 10 kg / minute to about 80 kg / minute. The present disclosure further provides a kit comprising the desulphurization reagent as claimed in claim 1 or a combination of about 12-18% w / w of CaSi, about 4-8% w / w of slag conditioner and about 1-5% w / w of melt agitator or gassifying agent and optionally about 70-80% w / w of a calcium bearing compound, about 0.05-5% w / w of a flow aid or fluidizer and / or about 1-10% w / w of a deoxidizer(s) or Reagent A and Reagent B as defined above, along with an instruction manual.

[0028] In some embodiments, also envisaged herein is use of the desulphurization reagent or the kit as defined above for desulphurizing hot metal.

[0029] In some embodiments, also envisaged herein is use of the desulphurization reagent or the kit as defined above for simultaneously desulphurizing hot metal and reducing FeO content in slag formed during desulphurization process.

[0030] In some embodiments, the desulphurization process as defined above yields a desulphurization efficiency of about 30% to about 100%; reduces hot metal sulphur level after desulphurization to about <=0.008% sulphur; and / or reduces FeO content in the process slag to about <=20%.

[0031] BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

[0032] In order that the disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with detailed description below, is incorporated in and forms part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure where:

[0033] Figure 1 depicts the results of flow index comparison between the desulphurization reagent of the present disclosure and a conventional reagent (base).

[0034] Figure 2 depicts the results of flow index comparison between the desulphurization reagent of the present disclosure and a conventional reagent (base). Figure 3 depicts response plots analyzing the impact of varying the concentration of CaSi, slag conditioner and melt agitator / gassifying agent in the desulphurization reagent within the defined concentration ranges on desulphurization efficiency and reduction of FeO content in the process slag.

[0035] Figures 4a and 4b depict two co-injection patterns of Reagent A and Reagent B into hot metal for desulphurization.

[0036] DETAILED DESCRIPTION OF THE INVENTION

[0037] In view of the limitations discussed above, and to remedy the need in the art for economical, safe and efficacious desulphurization reagent that is able to simultaneously remove sulphur from hot metal and reduce FeO content in the slag, the present disclosure provides a reagent comprising CaSi along with other ingredients such as slag conditioner(s), melt agitator(s) and gassifying agent(s) at specific concentration ranges, corresponding method of preparation of said desulphurization reagent, and application or use of said desulphurization reagent for desulphurization of hot metal (HMDS) during production of steel.

[0038] However, before describing the invention in greater detail, it is important to take note of the common terms and phrases that are employed throughout the present disclosure for better understanding of the technology provided herein.

[0039] General definitions

[0040] As used herein, the term ‘comprising’ when placed before the recitation of steps in a method means that the method encompasses one or more steps that are additional to those expressly recited, and that the additional one or more steps may be performed before, between, and / or after the recited steps. For example, a method comprising steps a, b, and c encompasses a method of steps a, b, x, and c, a method of steps a, b, c, and x, as well as a method of steps x, a, b, and c. Furthermore, the term “comprising” when placed before the recitation of steps in a method does not (although it may) require sequential performance of the listed steps, unless the content clearly dictates otherwise. For example, a method comprising steps a, b, and c encompasses, for example, a method of performing steps in the order of steps a, c, and b, the order of steps c, b, and a, and the order of steps c, a, and b, etc.

[0041] With respect to the use of substantially any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for sake of clarity. The suffix ‘(s)’ at the end of any term in the present disclosure envisages in scope both the singular and plural forms of said term.

[0042] As used in this specification and the appended claims, the singular forms ‘a’, ‘an’ and ‘the’ includes both singular and plural references unless the content clearly dictates otherwise. The use of the expression ‘at least’ or ‘at least one’ suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results. As such, the terms ‘a’ (or ‘an’), ‘one or more’, and ‘at least one’ can be used interchangeably herein.

[0043] Numerical ranges stated in the form ‘from x to y’ include the values mentioned and those values that lie within the range of the respective measurement as known to the skilled person. If several preferred numerical ranges are stated in this form, of course, all the ranges formed by a combination of the different end points are also included.

[0044] The terms ‘about’ or ‘approximately’ as used herein when referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, are meant to encompass variations of and from the specified value, such as variations of + / - 10% or less, + / -5% or less, + / -1% or less, and + / -0.1% or less of and from the specified value, insofar such variations are appropriate to perform in the disclosed invention. It is to be understood that the value to which the modifier ‘about’ or ‘approximately’ refers is itself also specifically, and preferably, disclosed.

[0045] As used herein, the terms ‘include’, ‘have’, ‘comprise’, ‘contain’ etc. or any form of said terms such as ‘having’, ‘including’, ‘containing’, ‘comprising’ or ‘comprises’ are inclusive and will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0046] As regards the embodiments characterized in this specification, it is intended that each embodiment be read independently as well as in combination with another embodiment. For example, in case of an embodiment 1 reciting 3 alternatives A, B and C, an embodiment 2 reciting 3 alternatives D, E and F and an embodiment 3 reciting 3 alternatives G, H and I, it is to be understood that the specification unambiguously discloses embodiments corresponding to combinations A, D, G; A, D, H; A, D, I; A, E, G; A, E, H; A, E, I; A, F, G; A, F, H; A, F, I; B, D, G; B, D, H; B, D, I; B, E, G; B, E, H; B, E, I; B, F, G; B, F, H; B, F, I; C, D, G; C, D, H; C, D, I; C, E, G; C, E, H; C, E, I; C, F, G; C, F, H; C, F, I, unless specifically mentioned otherwise.

[0047] Reference throughout this specification to “some embodiments”, “one embodiment”, “an embodiment”, “a preferred embodiment”, “a non-limiting embodiment” or “an exemplary embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases “in some embodiments”, “in one embodiment”, “in an embodiment”, “a preferred embodiment”, “a non-limiting embodiment” or “an exemplary embodiment” in various places throughout this specification may not necessarily all refer to the same embodiment. It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

[0048] Throughout this specification, the term ‘a combination thereof, ‘combinations thereof or ‘any combination thereof or ‘any combinations thereof are used interchangeably and are intended to have the same meaning, as regularly known in the field of patent disclosures.

[0049] As used herein, the term ‘desulphurization reagent’ refers to the product of the present disclosure comprising Calcium Silicide (CaSi) which can be employed for hot metal desulphurization process. The term “reagent” has also interchangeably been used in reference to the desulphurization reagent of the present disclosure.

[0050] As used herein, the phrase “hot metal desulphurization” refers to the removal of sulphur from hot metal. A non-limiting example of such hot metal includes hot metal obtained during the process of steel making.

[0051] As used herein, the term ‘desulphurization efficiency’ refers to the fraction or percentage of sulphur removed from the sample subjected to the desulphurization process.

[0052] “Success Rate” or “Strike Rate” as referred to interchangeably in the present disclosure is the measure of desulphurization efficiency. It is defined as the ratio of the number of batches / lots / heats in which the desired sulphur is achieved (with a tolerance of +0.001% Sulphur) to the total number of batches / lots / heats attempted for that particular level of sulphur. Disclosure

[0053] An objective of the present disclosure is to provide an alternate, economical, and less hazardous desulphurization reagent showcasing improved efficiency of desulphurization i.e. removal of sulphur from hot metal treated with the reagent. Still another objective of the present disclosure is to develop an alternate desulphurization reagent which can reduce overall cost and improve overall efficiency of HMDS process.

[0054] In some embodiments, the reduction in overall cost and less hazardous nature of the desulphurization reagent is achieved by exclusion of Magnesium (Mg) from the desulphurization reagent.

[0055] Therefore, an objective of the present invention is to devise a desulphurization reagent partially or completely devoid of magnesium.

[0056] A further objective of the present disclosure is to provide a desulphurization reagent that can effectively reduce iron(II) oxide (FeO) content in the slag arising from the desulphurization process. Said reduction of FeO content in the slag improves the process economy since it leads to an increase in the yield of prime metal i.e. iron.

[0057] In some embodiments, the present disclosure is directed towards a desulphurization reagent that can achieve a dual objective of removal of sulphur from hot metal as well as reduction of FeO content in the slag.

[0058] Accordingly, the present disclosure provides a desulphurization reagent comprising calcium silicide, slag conditioner(s) and melt agitator(s) or gassifying agent(s).

[0059] Particularly, the present disclosure provides a desulphurization reagent comprising about 12-18% w / w of CaSi, about 4-8% w / w of a slag conditioner and about 1-5% w / w of a melt agitator or gassifying agent.

[0060] In some embodiments, the present disclosure provides a desulphurization reagent having the CaSi, the slag conditioner and the melt agitator or gassifying agent at any concentration within the ranges as defined above. Non-limiting examples of the desulphurization reagent as described above are indicated in Table 1. In Table 1, 5 ‘X’ represents presence of the component at the specific concentration as marked in each column. Accordingly, every single combination provided in different rows of Table 1 represents a separate embodiment of the present disclosure. The below embodiments have been provided for the purpose of clear exemplification and do not exclude the possibility of the concentration of the components being values 10 intermediate between the concentrations indicated in individual columns or the possibility of incorporation of any further component in the desulphurization reagent.

[0061] Table 1:

[0062]

[0063] 5

[0064] As mentioned above, Table 1 is depictive of the different embodiments of the present invention wherein the desulphurization reagent comprises different concentrations of CaSi, the slag conditioner and the melt agitator or gassifying agent within the ranges as defined in preceding embodiments. Said table has 10 however been provided for the purposes of clear exemplification and does not exclude further possibilities that may arise from permutation and combination of the concentration of different concentrations of CaSi, the slag conditioner and the melt agitator or gassifying agent within the ranges as defined in preceding embodiments.

[0065] 15 In some embodiments, the desulphurization reagent further comprises an additional component selected from a group comprising a calcium bearing compound, a flow aid or fluidizer and a deoxidizer or any combination thereof.

[0066] In some embodiments, the slag conditioner is selected from a group comprising a sodium based compound, an aluminium based compound and a fluorine -based 20 compound or any combination thereof.

[0067] In some embodiments, the slag conditioner is selected from a group comprising cryolite, alumina, fluorspar, bauxite, soda ash and borax or any combination thereof. In some embodiments, the melt agitator is selected such that it generates enough vapor to create stirring effect in hot metal at temperatures lower than 1500°C.

[0068] In some embodiments, the melt agitator or gassifying agent is selected from a group comprising coal, limestone, dolomite and gilsonite or any combination thereof.

[0069] In some embodiments, the calcium bearing compound is selected from a group comprising lime, calcined lime, limestone and calcium chloride or any combination thereof.

[0070] In some embodiments, the calcium bearing compound is present in the desulphurization reagent at a concentration ranging from about 70%-80% w / w. The calcium bearing compound may be present in the reagent at any concentration within the defined range along with the combination of CaSi, slag conditioner and melt agitator or gassifying agent at the concentrations as defined in Table 1.

[0071] In some embodiments, the calcium bearing compound is present at a concentration ranging from about 70% w / w, about 71% w / w, about 72% w / w, about 73% w / w, about 74% w / w, about 75% w / w, about 75.5% w / w, about 76% w / w, about 77% w / w, about 78% w / w, about 79% w / w or about 80% w / w.

[0072] In some embodiments, the flow aid or fluidizer is selected from silicone oil and coal or a combination thereof.

[0073] In some preferred, non-limiting embodiments of the present disclosure, the flow aid or fluidizer is silicone oil.

[0074] In some embodiments, the flow aid or fluidizer is present in the desulphurization reagent at a concentration ranging from about 0.05-5% w / w. The flow aid may be present in the reagent at any concentration within the defined range along with the combination of CaSi, slag conditioner and melt agitator or gassifying agent at the concentrations as defined in Table 1 and optionally, the further calcium bearing compound(s) at the concentration as defined above.

[0075] In some embodiments, the flow aid or fluidizer is present at a concentration ranging from about 0.05% w / w, 0.1% w / w, 0.2% w / w, 0.3% w / w, 0.4% w / w, 0.5% w / w, 0.6% w / w, 0.7% w / w, 0.8% w / w, 0.9% w / w, 1% w / w, 2% w / w, 3% w / w, 4% w / w or 5% w / w.

[0076] In some embodiments, the deoxidizer is selected from a group comprising metallic aluminium, coal and coke or any combination thereof.

[0077] In preferred, non-limiting embodiments of the present application, the deoxidizer is metallic aluminium.

[0078] In some embodiments, the deoxidizer is present in the desulphurization reagent at a concentration ranging from about 1-10% w / w. The deoxidizer(s) may be present at any concentration within the defined range in combination with CaSi, slag conditioner and melt agitator or gassifying agent at the concentrations as defined in Table 1, optionally along with the further calcium bearing compound and the flow aid at the respective concentrations as defined above.

[0079] In some embodiments, the deoxidizer is present at a concentration ranging from about 1% w / w, about 2% w / w, about 3% w / w, about 4% w / w, about 5% w / w, about 6% w / w, about 7% w / w, about 8% w / w, about 9% w / w or about 10% w / w.

[0080] In some embodiments, the desulphurization reagent comprises about 12-18% w / w CaSi, about 4-8% w / w slag conditioner, and about 1-5% w / w melt agitator or gassifying agent.

[0081] In some embodiments, the desulphurization reagent comprises about 12-18% w / w CaSi, about 4-8% w / w slag conditioner, about 1-5% w / w melt agitator or gassifying agent, and about 70-80% w / w calcium bearing compound.

[0082] In some embodiments, the desulphurization reagent comprises about 12-18% w / w CaSi, about 4-8% w / w slag conditioner,

[0083] - about 1-5% w / w melt agitator or gassifying agent, and about 0.05-5% w / w flow aid or fluidizer.

[0084] In some embodiments, the desulphurization reagent comprises about 12-18% w / w CaSi, about 4-8% w / w slag conditioner,

[0085] - about 1-5% w / w melt agitator or gassifying agent, and about 1-10% w / w deoxidizer.

[0086] In some embodiments, the desulphurization reagent comprises about 12-18% w / w CaSi, about 4-8% w / w slag conditioner, about 1-5% w / w melt agitator or gassifying agent, about 70-80% w / w calcium bearing compound, and about 0.05-5% w / w flow aid or fluidizer.

[0087] In some embodiments, the desulphurization reagent comprises about 12-18% w / w CaSi, about 4-8% w / w slag conditioner, about 1-5% w / w melt agitator or gassifying agent, about 70-80% w / w calcium bearing compound, and about 1-10% w / w deoxidizer.

[0088] In some embodiments, the desulphurization reagent comprises about 12-18% w / w CaSi, about 4-8% w / w slag conditioner, about 1-5% w / w melt agitator or gassifying agent, about 0.05-5% w / w flow aid or fluidizer, and about 1-10% w / w deoxidizer.

[0089] In some embodiments, the desulphurization reagent comprises about 12-18% w / w CaSi, about 4-8% w / w slag conditioner, about 1-5% w / w melt agitator or gassifying agent, about 70-80% w / w calcium bearing compound, about 0.05-5% w / w flow aid or fluidizer, and about 1-10% w / w deoxidizer.

[0090] In some embodiments, the components of the desulphurization reagent defined in terms of absolute wt% values or wt% ranges are such that they make up the total percentage weight of the desulphurization reagent to 100%.

[0091] In some embodiments, the reagent is prepared in a pre-blended form and stored for use in the hot metal desulphurization process. In some embodiments, the reagent is prepared as a combination of components stored separately, wherein said components are then directly added to the hot metal desulphurization process.

[0092] In some embodiments, the reagent is formed in the reactor of the hot metal desulphurization process when components of a co-injection process variant are injected into the reactor. The components of the co-injection process variant are designed such that the concentration of the components in the final reagent formed by the two components adds upto the concentration of each component as defined above.

[0093] As mentioned above, one of the objectives of the present disclosure is to provide a desulphurization reagent that is able to achieve high efficiency of desulphurization (i.e., effective removal of sulphur from hot metal) while simultaneously reducing the FeO content in the slag. The present disclosure provides a desulphurization reagent that is defined by specific concentration of the components as stated above, specifically of the CaSi, slag conditioner and melt agitator or gassifying agents, wherein the said concentrations of components yield a synergistic effect with respect to both desulphurization efficiency as well as reduction of FeO content in the slag. In a non-limiting embodiment, the desulphurization reagent has desulphurization efficiency of about 30% to 100%.

[0094] In a non-limiting embodiment, hot metal sulphur level after desulphurization with the aforesaid reagent is reduced to about <=0.008% Sulphur.

[0095] In some embodiments, the desulphurization reagent reduces FeO content in the slag by about 20 to about 80%.

[0096] In some embodiments, the desulphurization reagent reduces FeO content in the slag by about 20% to about 70% as compared to conventional reagents such as those comprising lime, cryolite and / or calcium carbide.

[0097] In a non-limiting embodiment, the optimum or desired sulphur content in the hot metal after desulphurization (ADS%) ranges from about 0.001% to about 0.008%. In another non-limiting embodiment, the optimum or desired FeO content in the slag arising from the desulphurization process ranges from about 8% to about 30%, preferably about <=20%.

[0098] In an exemplary embodiment, the desulphurization reagent reduces hot metal sulphur level after desulphurization to about <=0.008% Sulphur and reduces FeO content in the slag to about <=20%.

[0099] Deviating from the above defined concentration of components, more specifically CaSi, slag conditioner and melt agitator or gassifying agent impacts efficiency of the desulphurization reagent, both with respect to the degree or efficiency of desulphurization as well as FeO content in the slag.

[0100] The present disclosure further provides a method for preparing the desulphurization reagent as described above, the method comprising: mixing about 12-18% w / w of the CaSi, about 4-8% w / w of the slag conditioner, about 1-5% w / w of the melt agitator or gassifying agent and optionally, the calcium bearing compound, the flow aid or fluidizer and / or the deoxidizer to obtain the desulphurization reagent. In some embodiments, the aforesaid method is not restricted by the order of mixing of components. In some embodiments, the components are contacted with each other sequentially and mixed to form the reagent, with no restriction on the order of contacting the respective components. In some embodiments, all components are contacted simultaneously and mixed to obtain the desulphurization reagent as described above.

[0101] In some embodiments of the above-described method, the contacting and mixing step described above comprises one or more of mixing the components, crushing, grinding, pulverising, or any combination thereof.

[0102] In some embodiments, the above-described method is carried out by employing a rod mill, ball mill, blender, crusher, grinder, pulverizer, or any combination thereof.

[0103] In some embodiments, the calcium bearing compound is employed at a concentration of about 70-80% w / w, the flow aid or fluidizer is employed at a concentration of about 0.05-5% w / w and the deoxidizer is employed at a concentration of about 1-10% w / w.

[0104] In embodiments of the above-described method, the concentrations or wt% of the components of the desulphurization are based on the embodiments of the product (desulphurizing reagent) as described above. For the sake of brevity and to avoid repetition, each of those embodiments are not being reiterated in the context of the method. However, each of the said embodiments, completely fall within the purview of the method of preparing the desulphurization reagent.

[0105] The present disclosure further relates to a process of desulphurization of hot metal during production of steel, the process comprising reacting the desulphurization reagent as described above with the hot metal to obtain desulphurized hot metal and sulfur rich slag.

[0106] In some embodiments, said process of the present disclosure is further characterized by the simultaneous reduction of FeO content in the slag along with the removal of sulphur from the hot metal. In some embodiments, in the aforesaid process, the desulphurization reagent is contacted with the hot metal for desulphurization through one or more of monoinjection process, co-inj ection process, multi -injection, pour-over process, ladle top addition or ladle bottom addition. In some embodiments, the process of desulphurization is carried out in single or multiple iterations.

[0107] In some embodiments, the desulphurization reagent is contacted with the hot metal for desulphurization at a flow rate of about lOkg / minute to about 80kg / minute.

[0108] In the mono-injection variant, all the components of the reagent are pre-blended or mixed and stored in a single silo / day-bin / transfer dispenser / injection dispenser and injected in hot metal ladle through a single injection / single lance / multi lance system.

[0109] In the co-injection and multi-injection variants, the components of the reagent are stored separately in more than one silo / day-bin / transfer dispenser / injection dispenser and injected in hot metal ladle through a co-injection / single lance system / multi lance system. The components of the reagent are designed such that when injected into the hot metal ladle, the concentration of the final reagent are in compliance with the ranges as defined above.

[0110] In the pour-over variant of the process, the reagent is stored / dumped at the bottom inside a ladle or any other suitable container and hot metal is poured over it from a torpedo ladle or any other pouring ladle. Alternatively, the reagent is added along with hot metal falling stream in the pour-over process.

[0111] In the ladle top addition variant of the process, the reagent is added over the hot metal and the stirring is affected by a gas injection system through top lance or bottom / side porous plugs or by a mechanical stirring system / impeller.

[0112] In the ladle bottom addition variant of the process, the reagent is added through porous plug / plugs placed at the bottom of the ladle or at the side walls of the ladle with the help of a carrier gas. In an exemplary, non-limiting embodiment of the present disclosure, the desulphurization reagent is contacted with the hot metal for desulphurization through mono-injection process.

[0113] In some embodiments, when the desulphurization reagent is contacted with the hot metal for desulphurization through mono-injection process, the reagent as defined above is directly injected in hot metal ladle through a single injection of the desulphurization reagent of the present disclosure as defined in the above embodiments.

[0114] In another exemplary, non-limiting embodiment of the present disclosure, the desulphurization reagent is contacted with the hot metal for desulphurization through co-injection process.

[0115] In a non-limiting embodiment, the co-injection variant of the process of desulphurization of hot metal comprises injecting into the hot metal ladle through two separate ports, two separate reagents (referred to as hereinafter as ‘reagent A’ and ‘reagent B’), which once injected into the hot metal ladle, together, form the desulphurization reagent of the present disclosure.

[0116] In some embodiments, the co-injection process comprises co-injecting Reagent A comprising about 20% to about 25% w / w of CaSi, about 1% to about 5% w / w of a melt agitator or gassifying agent, about 4% to about 10 % w / w of a slag conditioner, and optionally, one or both of about 60% to about 75% w / w of a calcium bearing compound and about 0.05% to about 0.5% w / w of a flow aid or fluidizer, and Reagent B comprising about 90% to about 97% w / w of calcium bearing compound and about 1% to about 10% w / w of slag conditioner, such that the final reagent contacted with the hot metal is the desulphurization reagent as described above.

[0117] In some embodiments, the co-injection process comprises co-injecting Reagent A comprising about 20% to about 25% w / w of CaSi, about 1% to about 5% w / w of a melt agitator or gassifying agent, about 4% to about 10 % w / w of a slag conditioner and about 60% to about 75% w / w of a calcium bearing compound, and Reagent B comprising about 90% to about 97% w / w of calcium bearing compound and about 1% to about 10% w / w of slag conditioner, such that the final reagent contacted with the hot metal is the desulphurization reagent as described above.

[0118] In some embodiments, the co-injection process comprises co-injecting Reagent A comprising about 20% to about 25% w / w of CaSi, about 1% to about 5% w / w of a melt agitator or gassifying agent, about 4% to about 10 % w / w of a slag conditioner, about 60% to about 75% w / w of a calcium bearing compound and about 0.05% to about 0.5% w / w of a flow aid or fluidizer, and Reagent B comprising about 90% to about 97% w / w of calcium bearing compound and about 1% to about 10% w / w of slag conditioner, such that the final reagent contacted with the hot metal is the desulphurization reagent as described above.

[0119] In some embodiments, the co-injection process comprises co-injecting Reagent A comprising about 20% to about 25% w / w of CaSi, about 1% to about 5% w / w of a gilsonite, about 4% to about 10 % w / w of a cryolite, about 60% to about 75% w / w of lime and about 0.05% to about 0.5% w / w of a silicone oil, and Reagent B comprising about 90% to about 97% w / w of lime and about 1% to about 10% w / w of cryolite, such that the final reagent contacted with the hot metal is the desulphurization reagent as described above.

[0120] In an exemplary embodiment, the co-injection process comprises co-injecting the Reagent A comprising about 24% w / w of the CaSi, about 2% w / w of the melt agitator or gassifying agent, about 6% w / w of the slag conditioner, about 67.9% w / w of the calcium bearing compound and about 0.1% w / w of the flow aid or fluidizer, and the Reagent B comprising about 96% w / w of the calcium bearing compound and about 4% w / w of the slag conditioner, such that the final reagent contacted with the hot metal is the desulphurization reagent as described above.

[0121] In another exemplary embodiment, the co-injection process comprises co-injecting the Reagent A comprising about 24% w / w of CaSi, about 2% w / w of gilsonite, about 6% w / w of cryolite, about 67.9% w / w of lime and about 0.1% w / w of silicone oil, and the Reagent B comprising about 96% w / w of lime and about 4% w / w of the cryolite, such that the final reagent contacted with the hot metal is the desulphurization reagent as described above.

[0122] In some embodiments, the ratio between Reagent A and Reagent B ranges from about 3: 1 to about 10: 1.

[0123] In some non-limiting embodiments, the co-injection process comprises co-injecting the Reagent A and the Reagent B into the hot metal simultaneously.

[0124] In some non-limiting embodiments, the co-injection process comprises co-injecting the Reagent A and the Reagent B into the hot metal in a sequential manner.

[0125] In some non-limiting embodiments, the co-injection process comprises co-injecting the Reagent A and the Reagent B into the hot metal in an interspersed manner.

[0126] In some embodiments, the co-injection process comprises co-injecting the Reagent A and the Reagent B into the hot metal either simultaneously, in an interspersed manner or in a sequential manner, or any combinations thereof.

[0127] In some embodiments, when the Reagent A and the Reagent B are co-injected in an interspersed manner, the injection of the individual reagents is performed at regular intervals, wherein at each time interval, patterns of co-injection may include:

[0128] X’ represents introduction of the Reagent as marked in each column; and wherein any of patterns 1, 2, 3 can be followed at each time interval determined by the user.

[0129] In a non-limiting, exemplary embodiment, in the co-injection variant of the desulphurization process as defined above, when the Reagent A and the Reagent B are co-injected in an interspersed manner, the co-injection is performed for a period of about 20 minutes, wherein at each minute between the 1stand the 14thminute, Reagent A is injected at a flow rate of about 30 kg / min to about 50 kg / min and injection of Reagent A is stopped at the 14thminute; wherein at each minute between the 14thand the 19thminute, Reagent B is injected at a flow rate of about 20 kg / min to about 50 kg / min and injection of Reagent B is stopped at the 19thminute.

[0130] In another non-limiting, exemplary embodiment, in the co-injection variant of the desulphurization process as defined above, when the Reagent A and the Reagent B are co-injected in an interspersed manner, the co-injection is performed for a period of about 20 minutes, wherein at each minute between the 1stand the 2ndminute, Reagent B is injected at a flow rate of about 30 kg / min to about 40 kg / min and injection of Reagent B is paused at the 2ndminute; wherein at each minute between the 2ndand the 15thminute, Reagent A is injected at a flow rate of about 40 kg / min to about 50 kg / min and injection of Reagent A is stopped at the 15thminute; and wherein at each minute between the 15thand the 18thminute, injection of Reagent B is resumed at a flow rate of about 40 kg / min to about 50 kg / min and injection of Reagent B is stopped at the 18thminute.

[0131] In some embodiments, the desulphurization reagent of the present disclosure is contacted with the hot metal at a ratio of about 9: 10000 to about 1: 100 by weight, based on initial sulphur levels in the hot metal.

[0132] In some embodiments, the desulphurization reagent is contacted with the hot metal at a temperature ranging from about 1275°C to about 1450°C.

[0133] In embodiments of the above-described process, the concentrations or wt% of the ingredients / components of the desulphurization are based on the embodiments of the product (desulphurizing reagent) as described above. For the sake of brevity and in order to avoid repetition, each of those embodiments are not being reiterated here in the context of the aforesaid process. However, each of the said embodiments completely fall within the purview of the process of desulphurization of hot metal during production of steel. In some embodiments, the aforesaid process has desulphurization efficiency of about 30% to about 100%.

[0134] In a non-limiting embodiment, the sulphur level in the hot meal after desulphurization with the desulphurization reagent of the present disclosure is reduced to about <=0.008% Sulphur.

[0135] In some embodiments, the aforesaid process reduces FeO content in the slag to about <=20%.

[0136] In some embodiments, the aforesaid process reduces hot metal sulphur level after desulphurization to about <=0.008% Sulphur and reduces FeO content in the slag to about <=20%.

[0137] In some embodiments, the aforesaid process reduces the cost of desulphurization reagent by alteast 5%.

[0138] The present disclosure further provides a kit comprising the desulphurization reagent as described above or a combination of about 12-18% w / w of CaSi, about 4-8% w / w of slag conditioner and about 1-5% w / w of melt agitator or gassifying agent and optionally about 70-80% w / w of a calcium bearing compound, about 0.05-5% w / w of a flow aid or fluidizer and / or about 1-10% w / w of a deoxidizer(s) or Reagent A and Reagent B as described above, along with an instruction manual.

[0139] In an exemplary embodiment, the present disclosure provides a kit comprising Reagent A comprising about 20% to about 25% w / w of CaSi, about 1% to about 5% w / w of a melt agitator or gassifying agent, about 4% to about 10 % w / w of a slag conditioner and optionally, one or both of about 60% to about 75% w / w of a calcium bearing compound and about 0.05% to about 0.5% w / w of a flow aid or fluidizer; and Reagent B comprising about 90% to about 97% w / w of slag conditioner and about 1% to about 10% w / w of slag conditioner, along with an instruction manual.

[0140] In another exemplary embodiment, the present disclosure provides a kit comprising Reagent A comprising about 20% to about 25% w / w of CaSi, about 1% to about 5% w / w of a melt agitator or gassifying agent, about 4% to about 10 % w / w of a slag conditioner, about 60% to about 75% w / w of a calcium bearing compound and about 0.05% to about 0.5% w / w of a flow aid or fluidizer; and Reagent B comprising about 90% to about 97% w / w of slag conditioner and about 1% to about 10% w / w of slag conditioner, along with an instruction manual.

[0141] In some embodiments, the instruction manual contains instructions for use of the desulphurization reagent or the combination of components constituting the desulphurization reagent or the Reagent A and the Reagent B.

[0142] In some embodiments, the kit described above further comprises means for facilitating introduction of the desulphurization reagent or the combination of components constituting the desulphurization reagent or the reagents into hot metal for desulphurization of the hot metal.

[0143] The present disclosure further provides use of the desulphurization reagent as described above or the kit as described above for desulphurizing hot metal wherein removal of sulphur from the hot metal is facilitated along with simultaneous reduction of FeO content in the process slag.

[0144] The present disclosure further provides use of the desulphurization reagent as described above or the kit as described above for desulphurizing hot metal before primary steelmaking.

[0145] As mentioned above, the desulphurization reagent and / or the kit removes sulphur from the hot metal during the production of steel resulting in the manufacture of desulphurized or low sulphur steel while simultaneously reducing FeO content in the slag formed in the desulphurization process.

[0146] The present disclosure further provides use of the desulphurization reagent as described above or the kit as described above for desulphurizing hot metal by means of a mono-injection process, co-injection process, multi-injection, pour-over process, ladle top addition or ladle bottom addition. In a preferred embodiment, the present disclosure provides use of the desulphurization reagent as described above or the kit as described above for desulphurizing hot metal by means of a mono-injection process or a co-injection process.

[0147] In an exemplary embodiment, the present disclosure provides use of the desulphurization reagent as described above or the kit as described above for desulphurizing hot metal by means of a co-injection process.

[0148] In some embodiments, the present disclosure provides use of the desulphurization reagent as described above or the kit as described above for desulphurizing hot metal by means of a mono-injection process wherein all the components of the reagent(s) are pre-blended or mixed and stored in a single silo / day-bin / transfer dispenser / injection dispenser and injected in hot metal ladle through a single injection / single lance / multi lance system.

[0149] In some embodiments, the present disclosure provides use of the desulphurization reagent as described above or the kit as described above for desulphurizing hot metal by means of a co-injection process, wherein the components of the reagent(s) are stored separately in more than one silo / day-bin / transfer dispenser / injection dispenser and injected in hot metal ladle through a co-injection / single lance system / multi lance system.

[0150] In some embodiments, the present disclosure provides use of the desulphurization reagent as described above or the kit as described above for desulphurizing hot metal by means of a pour-over method in which the reagent(s) is stored / dumped at the bottom inside a ladle or any other suitable container and hot metal is poured over it from a torpedo ladle or any other pouring ladle. Alternatively, the reagent(s) is added along with hot metal falling stream in the pour-over method.

[0151] In some embodiments, the present disclosure provides use of the desulphurization reagent as described above or the kit as described above for desulphurizing hot metal by means of ladle top addition wherein the reagent(s) is added over the hot metal and the stirring is affected by a gas injection system through top lance or bottom / side porous plugs or by a mechanical stirring system / impeller.

[0152] In some embodiments, the present disclosure provides use of the desulphurization reagent as described above or the kit as described above for desulphurizing hot metal by means of ladle bottom addition wherein the reagent(s) is added through porous plug / plugs placed at the bottom of the ladle or at the side walls of the ladle with the help of a carrier gas.

[0153] In some embodiments, the concentrations or wt% of the ingredients / components of the desulphurization reagent are based on the embodiments of the product (desulphurizing rcagcntj / proccss as described above. For the sake of brevity and in order to avoid repetition, each of those embodiments are not reiterated here in the content of the use. However, each of the said embodiments completely fall within the purview of the use the reagent in affecting the desulphurization of hot metal during production of steel.

[0154] In some embodiments, aforesaid use yields a desulphurization efficiency of about 30% to about 100 %, preferably reducing sulphur level in the hot metal subjected to desulphurization to about <=0.008% Sulphur.

[0155] In some embodiments, the aforesaid use reduces FeO content in the process slag to about <=20%.

[0156] In some embodiments, the aforesaid use reduces hot metal sulphur level after desulphurization to about <=0.008% Sulphur and simultaneously reduces FeO content in the process slag to about <=20%.

[0157] It is to be understood that the foregoing descriptive matter is illustrative of the disclosure and not a limitation. While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. Those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein. Similarly, additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based upon description provided herein.

[0158] Descriptions of well-known / conventional methods / steps and techniques are omitted so as to not unnecessarily obscure the embodiments herein. Further, the disclosure herein provides for examples illustrating the above-described embodiments, and in order to illustrate the embodiments of the present disclosure certain aspects have been employed. The examples used herein for such illustration are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the following examples should not be construed as limiting the scope of the embodiments herein.

[0159] While the present disclosure is susceptible to various modifications and alternative forms, specific aspects thereof have been shown by way of examples and drawings and are described in detail below. However, it should be understood that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and the scope of the invention as defined by the appended claims.

[0160] EXAMPLES:

[0161] The present disclosure is further described with reference to the following examples, which are only illustrative in nature and should not be construed to limit the scope of the present disclosure in any manner.

[0162] Example 1:

[0163] Three 5kg batches of the desulphurization reagent of the present invention were ptarepared wherein the components of the composition were contacted, mixed and agitated in a ball mill, in which the weight of the grinding media was about 20 Kg. The grinding of the components at the following concentrations was performed at NTP i.e. about 1 atm and about 25°C -

[0164] Reagent I (Sample 1) - About 12% CaSi, about 8% slag conditioner, about 2% bath agitator, about 0.07% fluidizer and rest CaO.

[0165] Reagent II (Sample 2) - About 16% CaSi, about 6% slag conditioner, about 2% bath agitator, about 0.05% fluidizer and rest CaO.

[0166] Parameters like flowability and granulometry of the prepared reagent were studied to confirm its usability in the actual plant application. The results as depicted in Fig. l and Fig.2 respectively show that the two assessed parameters were found to be improved as compared to the values observed for the conventional desulphurization reagent comprising CaC2, slag conditioner, bath agitator and CaO (base). Based on these results, the reagent was found to be suitable for the further trials.

[0167] Example 2:

[0168] Different desulphurization reagents falling within and outside the purview of the reagent of the present disclosure as described above were prepared by employing varying concentrations of CaSi, cryolite (slag conditioner), gilsonite (melt agitator / gassifying agent), lime (calcium bearing compound) and silicone oil (flow aid) as per the method of Example 1. Further, the said desulphurization reagents were employed in pilot scale experiments using different batches of hot metal comprising similar sulphur content before desulphurization employing the following parameters -

[0169] Hot metal Temperature - About 1275°C - 1450°C

[0170] N2 flow rate - About 40 Nm3 / min

[0171] New Reagent Flow rate - About 45 kg / min - 60 kg / min

[0172] Back pressure - About 4 bar - 5 bar

[0173] DS Cycle time - About 20 minutes - 30 minutes

[0174] Heat size - About 160 tonnes - 335 tonnes 5 Initial Hot metal Sulphur content - About 0.020%-0.045%

[0175] The observations were as follows:

[0176] Table 2:

[0177] As can be observed from the above table, desulphurization reagents comprising the 10 respective components at concentrations outside the ranges as defined in the present disclosure show a comparatively higher ADS%, with lower strike rate. Therefore, it is clear that the specific concentration of components as defined in the present 5 disclosure plays a key role in determining the efficiency of the desulphurization reagent.

[0178] Example 3:

[0179] The effect of varying the concentration of CaSi, cryolite (slag conditioner) and gilsonite (melt agitator / gassifying agent) in the desulphurization reagent on the 10 intended dual function of removal of sulphur from the treated hot metal (i.e. desulphurization) and reduction of FeO content in the slag was analyzed through the following experiments wherein the desulphurization reagents were employed in laboratory scale desulphurization experiments using different batches of hot metal comprising similar sulphur content before desulphurization-

[0180] 15 Table 3: *measurement error within acceptable limits

[0181] As observable from the above table, even a minor deviation from the concentration of CaSi, cryolite (slag conditioner) and gilsonite (melt agitator / gassifying agent) in the desulphurization reagent as defined in the present disclosure leads to a significant increase in the FeO content in the slag arising from the desulphurization process and / or a decrease in the efficiency of desulphurization (i.e. increase in ADS% and decrease in strike rate). The desulphurization reagent of the present disclosure however, achieves both - efficient removal of sulphur from the treated hot metal (i.e. desulphurization) as well as reduction of FeO content in the slag. When the desulphurization process is performed on an industrial scale, said impact of the reagent on the desulphurization process will have a significant impact on the process economy.

[0182] Example 4:

[0183] The impact of varying the concentration of CaSi, cryolite (slag conditioner) and gilsonite (melt agitator / gassifying agent in the desulphurization reagent within the defined concentration ranges was analyzed by carrying out pilot scale experiments employing reagents wherein the concentration of CaSi, cryolite (slag conditioner) and gilsonite (melt agitator / gassifying agent) were individually varied within the ranges of about 12-18 wt%, about 4-8 wt% and about 1-5 wt%, respectively while keeping the concentration of other components constant.

[0184] Response plots (Fig. 3) were then created based on the following observations -

[0185] Table 4: 5 It was found that the desulphurization reagent having CaSi, along with the slag conditioner and melt agitator / gassifying agent at the concentrations defined in the present disclosure yielded ADS% within the targeted range of <=0.008% S and FeO content in the slag was simultaneously reduced to the targeted range of <=20%.

[0186] Example 5:

[0187] 10 Desulphurization process by means of co-injection was studied in this example. Reagent A comprising CaSi, lime (Ca bearing compound), gilsonite (melt agitator), cryolite (slag conditioner) and silicone oil (flow aid) was prepared in the concentrations and quantity shown in Table 5 below. Additionally, a Reagent B comprising lime (Ca bearing compound) and cryolite (slag conditioner) was also

[0188] 15 prepared in the concentrations and quantity shown in Table 5. As shown in the table, a combination of Reagent A and Reagent B yielded a final reagent when injected into the hot metal desulphurization process, which is essentially the desulphurization reagent of the present disclosure (Table 5, last column).

[0189] Table 5:

[0190] Reagent A and Reagent B were introduced into the hot metal for desulphurization through co-inj ection process. Two different injection patterns were followed. In the first pattern, as shown in Table 6 below and Figure 4a, the Reagent A and Reagent B were co-injected into the hot metal sequentially, i.e., from 1 to 14 minutes, only 25 Reagent A was injected at a flow rate of about 30 kg / min (minute 1) or about 50 kg / min (minutes 2-14). Injection of Reagent A was then stopped and from the 14th minute till the 19thminute, Reagent B was inj ected at a flow rate of about 30 kg / min (minute 14) or about 50 kg / min (minutes 15-18) or about 20 Kg / min (minute 19). At minute 20, the injection was terminated.

[0191] Table 6: In the second pattern, as shown in Table 7 below and Figure 4b, Reagent A and Reagent B were co-injected into the hot metal in an interspersed manner. From 2 to 15 minutes, Reagent A was injected at a flow rate of about 40 kg / min (minutes 2- 15) or about 50 kg / min (minutes 3-14). Injection of Reagent A was then stopped. Reagent B was injected at a flow rate of 30 kg / min at minute 1 and at a flow rate of about 40 kg / min at minute 2 and then suspended. Injection of Reagent B was then resumed from minute 15 and continued till minute 18 at a flow rate of about 40 kg / min (minutes 15 and 18) or about 50 Kg / min (minutes 16-17). At minute 19, the injection was terminated.

[0192] Table 7:

[0193] In the above co-inj ection processes, it was observed that favorable results with respect to desulphurization efficiency and FeO reduction in slag were obtained, in line with the ranges captured in the above defined embodiments of the present disclosure.

[0194] The foregoing description fully reveals the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without departing from the general concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments in this disclosure have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein, without departing from the principles of the disclosure.

[0195] Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure . It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

Claims

We Claim:

1. A desulphurization reagent comprising about 12-18% w / w of CaSi, about 4-8% w / w of a slag conditioner and about 1-5% w / w of a melt agitator or gassifying agent.

2. The desulphurization reagent as claimed in claim 1, further comprising an additional component selected from a group comprising a calcium bearing compound, a flow aid or fluidizer and a deoxidizer or any combination thereof.

3. The desulphurization reagent as claimed in claim 1, wherein the slag conditioner is selected from a group comprising a sodium based compound, an aluminium based compound and a fluorine-based compound or any combination thereof.

4. The desulphurization reagent as claimed in claim 3, wherein the slag conditioner is selected from a group comprising cryolite, alumina, fluorspar, bauxite, soda ash and borax or any combination thereof.

5. The desulphurization reagent as claimed in claim 1, wherein the melt agitator or gassifying agent is selected from a group comprising coal, limestone, dolomite and gilsonite or any combination thereof.

6. The desulphurization reagent as claimed in claim 2, wherein the calcium bearing compound is selected from a group comprising lime, calcined lime, limestone and calcium chloride or any combination thereof, and / or wherein the calcium bearing compound is present at a concentration ranging from about 70-80% w / w.

7. The desulphurization reagent as claimed in claim 2, wherein the flow aid or fluidizer is selected from silicone oil and coal or a combination thereof, preferably silicone oil; and / or wherein the flow aid or fluidizer is present at a concentration ranging from about 0.05-5% w / w.

8. The desulphurization reagent as claimed in claim 2, wherein the deoxidizer is selected from a group comprising metallic aluminium, coal and coke or any combination thereof, preferably metallic aluminium; and / or the deoxidizer is present at a concentration ranging from about 1-10% w / w.

9. The desulphurization reagent as claimed in any one of claims 1-8, wherein the desulphurization reagent comprises:(i) (a) about 12-18% w / w CaSi,(b) about 4-8% w / w slag conditioner, and(c) about 1-5% w / w melt agitator or gassifying agent;Or,(ii) (a) about 12-18% w / w CaSi,(b) about 4-8% w / w slag conditioner,(c) about 1-5% w / w melt agitator or gassifying agent, and(d) about 70-80% w / w calcium bearing compound;Or,(iii) (a) about 12-18% w / w CaSi,(b) about 4-8% w / w slag conditioner,(c) about 1-5% w / w melt agitator or gassifying agent, and(d) about 0.05-5% w / w flow aid or fluidizer;Or,(iv) (a) about 12-18% w / w CaSi,(b) about 4-8% w / w slag conditioner,(c) about 1-5% w / w melt agitator or gassifying agent, and(d) about 1-10% w / w deoxidizer;Or,(v) (a) about 12-18% w / w CaSi,(b) about 4-8% w / w slag conditioner,(c) about 1-5% w / w melt agitator or gassifying agent,(d) about 70-80% w / w calcium bearing compound, and(e) about 0.05-5% w / w flow aid or fluidizer;Or,(vi) (a) about 12-18% w / w CaSi,(b) about 4-8% w / w slag conditioner,(c) about 1-5% w / w melt agitator or gassifying agent,(d) about 70-80% w / w calcium bearing compound, and(e) about 1-10% w / w deoxidizer;Or,(vii) (a) about 12-18% w / w CaSi,(b) about 4-8% w / w slag conditioner,(c) about 1-5% w / w melt agitator or gassifying agent,(d) about 0.05-5% w / w flow aid or fluidizer, and(e) about 1-10% w / w deoxidizer;Or,(viii) (a) about 12-18% w / w CaSi,(b) about 4-8% w / w slag conditioner,(c) about 1-5% w / w melt agitator or gassifying agent,(d) about 70-80% w / w calcium bearing compound,(e) about 0.05-5% w / w flow aid or fluidizer, and(f) about 1-10% w / w deoxidizer.

10. A method for preparing the desulphurization reagent as claimed in any one of claims 1-9, the method comprising: mixing about 12-18% w / w of the CaSi, about 4-8% w / w of the slag conditioner, about 1-5% w / w of the melt agitator or gassifying agent and optionally, the calcium bearing compound, the flow aid or fluidizer and / or the deoxidizer to obtain the desulphurization reagent.

11. The method as claimed in claim 10, wherein the mixing step comprises mixing the components, crushing, grinding, pulverising, or any combination of said techniques; and wherein said mixing is carried out by employing a rod mill, ball mill, blender, crusher, grinder, pulverizer, or any combination thereof.

12. The method as claimed in claim 10, wherein the calcium bearing compound is employed at a concentration of about 70-80% w / w, the flow aid or fluidizer is employed at a concentration of about 0.05-5% w / w and the deoxidizer is employed at a concentration of about 1-10% w / w.

13. A process of desulphurization of hot metal during production of steel, the process comprising contacting the desulphurization reagent as claimed in any one of claims 1-9 with the hot metal to obtain desulphurized hot metal and sulfur rich slag.

14. The process as claimed in claim 13, wherein the process also results in the simultaneous reduction of FeO content in the slag along with the removal of sulphur from the hot metal.

15. The process as claimed in claim 13, wherein the desulphurization reagent is contacted with the hot metal for desulphurization through one or more of mono-injection process, co-injection process, multi-injection, pour-over process, ladle top addition or ladle bottom addition.

16. The process as claimed in claim 15, wherein the desulphurization reagent is contacted with the hot metal for desulphurization through mono-injection process.

17. The process as claimed in claim 15, wherein the desulphurization reagent is contacted with the hot metal for desulphurization through co-injection process.

18. The process as claimed in claim 17, wherein the co-injection process comprises co-injecting Reagent A comprising about 20% to about 25% w / w of CaSi, about 1% to about 5% w / w of a melt agitator or gassifying agent and about 4% to about 10 % w / w of a slag conditioner, and Reagent B comprising about 90% to about 97% w / w of calcium bearing compound and about 1% to about 10% w / w of slag conditioner, such that the final reagent contacted with the hot metal is the desulphurization reagent as claimed in any one of claims 1-9.

19. The process as claimed in claim 18, therein the Reagent A further comprises about 60% to about 75% w / w of a calcium bearing compound and about 0.05% to about 0.5% w / w of a flow aid or fluidizer.

0. The process as claimed in claim 19, wherein the co-injection process comprises co-injecting the Reagent A comprising about 24% w / w of the CaSi, about 2% w / w of the melt agitator or gassifying agent, about 6% w / wof the slag conditioner, about 67.9% w / w of the calcium bearing compound and about 0.1% w / w of the flow aid or fluidizer, and the Reagent B comprising about 96% w / w of the calcium bearing compound and about 4% w / w of the slag conditioner, such that the final reagent contacted with the hot metal is the desulphurization reagent as claimed in any one of claims 1- 9. The process as claimed in any of claims 18-20, wherein the ratio between the Reagent A and the Reagent B ranges from about 3 : 1 to about 10:

1. The process as claimed in any one of claims 13-21, wherein the desulphurization reagent is contacted with the hot metal at a ratio of about 9: 10000 to about 1: 100 by weight; and / or wherein the desulphurization reagent is contacted with the hot metal at a temperature ranging from about 1275°C to about 1450 °C. The process as claimed in any one of claims 13-22, wherein the desulphurization reagent is contacted with the hot metal at a flow rate of about 10 kg / minute to about 80 kg / minute. A kit comprising the desulphurization reagent as claimed in claim 1, or a combination of about 12-18% w / w of CaSi, about 4-8% w / w of slag conditioner and about 1-5% w / w of melt agitator or gassifying agent and optionally about 70-80% w / w of a calcium bearing compound, about 0.05- 5% w / w of a flow aid or fluidizer and / or about 1-10% w / w of a deoxidizer(s), or Reagent A and Reagent B as defined in claim 18 or 19, along with an instruction manual. The kit as claimed in claim 24, further comprising means for facilitating introduction of the desulphurization reagent or the combination of components constituting the desulphurization reagent or the reagents into hot metal for desulphurization of the hot metal. Use of the desulphurization reagent as claimed in any one of claims 1-9 or the kit as claimed in any one of claims 24 to 25 for desulphurizing hot metal. Use of the desulphurization reagent as claimed in any one of claims 1-9 or the kit as claimed in any one of claims 24 to 25 for simultaneouslydesulphurizing hot metal and reducing FeO content in slag formed during desulphurization process. The use as claimed in any of claims 26 to 27, comprising contacting the desulphurizing reagent with the hot metal by means of a mono-injection process, co-injection process, multi-injection, pour-over process, ladle top addition or ladle bottom addition. The use as claimed in claim 28, comprising contacting the desulphurizing reagent with the hot metal by means of a co-injection process. The process as claimed in any of claims 22-23 or the use as claimed in any of claims 26-29, wherein said process or use yields a desulphurization efficiency of about 30% to about 100 %; reduces hot metal sulphur level after desulphurization to about <=0.008% sulphur; and / or reduces FeO content in the process slag to about <=20%.

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