Claims:WE CLAIM:
1. A method for producing low phosphorous steel from low silicon high phosphorous hot metal in basic oxygen furnace process, characterized in that-
- retaining slag in the process in an amount ranging from about 25% to 50%;
- adding lime in the process in at least three batches till at least 25% of blowing; and

2. The method as claimed in claim 1, wherein the method additionally comprises reducing total lime addition by about 10% to 12%.

3. The method as claimed in claim 1, wherein slag basicity is ranging from about 3.2 to 3.6.

4. The method as claimed in claim 1, wherein FeO content in the slag is ranging from about 12% to 18%.

5. The method as claimed in claim 1, wherein the steel comprises- carbon content ranging from about 0.03% to 0.06%; silicon content ranging from about 0.001% to 0.005%; and phosphorous content ranging from about 0.010% to 0.018%.

6. The method as claimed in claim 1, wherein the lime is added in five batches till 25% blowing.

7. The method as claimed in claim 6, wherein first batch of the lime addition is carried out at 0% blowing; second batch of the lime addition is carried out at about 5% blowing; third batch of the lime addition is carried out at about 10% blowing; and the fourth batch of lime addition is carried out at about 20% blowing; and the fifth batch of lime addition is carried out at about 25% blowing.

8. The method as claimed in claim 7, wherein amount of lime added in the first batch is ranging from about 2000 kg to 4000 kg; amount of lime added in the second batch is ranging from about 1000 kg to 2000 kg; amount of lime added in the third batch is ranging from about 500 kg to 1500 kg; and amount of lime added in the fourth batch is ranging from about 500 kg to 1500 kg; and amount of lime added in the fifth batch is ranging from about 250 kg to 750 kg.

9. The method as claimed in claim 1, wherein free lime in the slag is ranging from about 4 % to 8%.

10. The method as claimed in claim 1, wherein turndown or tapping temperature in the method is ranging from about 1620 deg C to 1680 deg C.

11. The method as claimed in claim 1, wherein dephosphorization rate is ranging from about 90% to 95%.

12. The method as claimed in claim 1, wherein the phosphorous content in the hot metal is lowered from 0.16 % to 0.014%.

Dated this 08th day of February 2022
Signature:
Name: Sridhar R
To: Of K&S Partners, Bangalore
The Controller of Patents Agent for the Applicant
The Patent Office, at Kolkata IN/PA-2598

, Description:TECHNICAL FIELD
The present disclosure relates to field of metallurgy and material sciences. The present disclosure particularly relates to steel making. More particularly, the present disclosure relates to method of producing low phosphorous steel from low silicon high phosphorous hot metal in basic oxygen furnace (BOF) process. The present disclosure provides an improved method of producing low phosphorous steel.

BACKGROUND OF THE DISCLOSURE
Basic oxygen furnace (BOF) process is one of the primary steelmaking process, which uses input materials like hot metal coming from blast furnace, solid steel scrap, pure oxygen, flux as calcined lime, raw dolomite (dolo), and iron ore as coolant and outputs are liquid steel, hot gas and liquid slag. Steel is produced in BOF process after slag splashing, addition of calcined lime and raw dolomite at zero batch and then adding the solid scrap on the top of zero batch and then charging liquid hot metal.

Due to significant increase in global demand and steel brining higher volume of blast furnaces, producing steel from low silicon and high phosphorous content was attempted. However, in the absence of any specific or improved pre-treatment process for production of low phosphorous steel on consistent basis in BOF process from relatively high phosphorous hot metal or liquid iron was a challenging task.

In the existing techniques for producing low phosphorous steel, dephosphorization of low silicon high phosphorous hot metal was carried out by features, such as- adding silica source material in BOF process and increasing the addition of lime quantity. However, adding silica source in the BOF process and adding higher lime was known to increase the production cost and it was noted that the process was operated at higher basicity, i.e., greater than 3.8, which was not ideal for producing low phosphorous steel.

Thus, there was a need for efficient and economical method for production of low phosphorus steel in the BOF process with effective dephosphorization.

The present disclosure describes an improved and economical method for production of low phosphorous steel from low silicon high phosphorous hot metal with improved dephosphorization rate.
STATEMENT OF THE DISCLOSURE
The present disclosure relates to simple, economical, environmentally and an improved method of producing low phosphorous steel from low silicon high phosphorous hot metal in basic oxygen furnace (BOF) process, characterized in that- retaining slag in the process in an amount ranging from about 25% to 50%; adding lime in at least three batches till at least 25% of blowing; and reducing quantity of lime addition by about 10% to 12%.

In an embodiment, the method of producing steel in the present disclosure provides for improved dephosphorization of steel by retaining slag in the process in an amount ranging from about 25% to 50%; and adding lime in the process in at least three batches until at least 25% of blowing.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
In order that the present 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, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, where:

FIGURE 1 illustrates a plot describing presence of free slime in collected turndown slag.

FIGURE 2 illustrates a plot describing relationship between slag basicity and % free lime in slag.

FIGURE 3 illustrates lime addition in the conventionally known basic oxygen furnace (BOF) process.

FIGURE 4 illustrates lime addition (modified lime addition pattern) according to the method of the present disclosure for producing low phosphorus steel.

DETAILED DESCRIPTION OF THE DISCLOSURE
Unless otherwise defined, all terms used in the disclosure, including technical and scientific terms, have meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. By means of further guidance, term definitions are included for better understanding of the present disclosure.

As used herein, the singular forms ‘a’, ‘an’ and ‘the’ include both singular and plural referents unless the context clearly dictates otherwise.

The term ‘comprising’, ‘comprises’ or ‘comprised of’ as used herein are synonymous with ‘including’, ‘includes’, ‘containing’ or ‘contains’ and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps.

The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within the respective ranges, as well as the recited endpoints.

The term ‘about’ as used herein when referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of ±10% or less, preferably ±5% or less, more preferably ±1% or less and still more preferably ±0.1% or less of and from the specified value, insofar such variations are appropriate to perform the present disclosure. It is to be understood that the value to which the modifier ‘about’ refers is itself also specifically, and preferably disclosed.

Reference throughout this specification to ‘some embodiments’, ‘one embodiment’ or ‘an 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’ or ‘in an 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.

The present disclosure relates to an improved method of producing low phosphorous steel from low silicon high phosphorous hot metal in basic oxygen furnace (BOF) process.

The inventors in the present disclosure have particularly identified a method which can provide for improved dephosphorization of low silicon high phosphorous hot metal, thereby producing low phosphorous steel when compared to conventionally known basic oxygen furnace (BOF) process, by reducing the flux addition and modifying the pattern of flux addition, such as lime during the process of steel making.

In an embodiment of the present disclosure, the method of producing low phosphorus steel from low silicon high phosphorous hot metal in basic oxygen furnace (BOF) process comprises the following distinctive features or characterizing features when compared to conventional process-
- Reducing flux (lime) addition in the process by about 10% to 12%;
- Retaining slag in the process in an amount ranging from about 25% to 50%; and
- Adding lime in the process in at least three batches until at least 25% of blowing.

The inventors of the present disclosure have particularly identified that by following the below mentioned distinctive features or characterizing features in the basic oxygen furnace (BOF) process for steelmaking- i. Reducing flux addition by about 10 to 12% ii. retaining slag in the process in an amount ranging from about 25% to 50%; and iii. adding lime in the process in at least three batches until at least 25% of blowing, the method provides for about improved dephosphorization of steel and thus produces low phosphorous steel in an economical manner when compared to conventional steel making process. The inventors have identified that by following said distinctive features or characterizing features, they are able to reduce phosphorous content in the steel by at least 23% when compared to the conventional steel making process wherein there is about 10% to 25% retention of slag and no adding of lime in at least three batches until at least 25% of blowing.

In some embodiments of the present disclosure, slag basicity in the method is ranging from about 3.2 to 3.6.

In some embodiments of the present disclosure, slag basicity in the method is about 3.2, about 3.3, about 3.4, about 3.5 or about 3.6.

In some embodiments of the present disclosure, the FeO content in the slag is ranging from about 12% to 18%.

In some embodiments of the present disclosure, the FeO content in the slag is about 12%, about 13%, about 14%, about 15%, about 16%, about 17% or about 18%.

In some embodiments of the present disclosure, the low phosphorus steel comprises- carbon content ranging from about 0.03% to 0.06%, silicon content ranging from about 0.001% to 0.005%, phosphorous content ranging from about 0.010% to 0.018%.

In some embodiments of the present disclosure, the low phosphorus steel comprises carbon content ranging from about 0.03%, about 0.04%, about 0.05% or about 0.06%.

In some embodiments of the present disclosure, the low phosphorus steel comprises silicon content ranging from about 0.001%, about 0.002%, about 0.003%, about 0.004% or about 0.005%.

In some embodiments of the present disclosure, the low phosphorus steel comprises phosphorous content ranging from about 0.010%, about 0.011%, about 0.012%, about 0.013%, about 0.014%, about 0.015%, about 0.016%, about 0.017% or about 0.018%.

In some embodiments of the present disclosure, the lime is added in about 3 batches to 5 batches from about 0% blowing to 25 blowing.

In some embodiments of the present disclosure, the lime is added in about 3 batches until about 25% of blowing.

In some embodiments of the present disclosure, the lime is added in about 4 batches until about 25% of blowing.

In some embodiments of the present disclosure, addition of the lime in about 5 batches until about 25% of blowing.

In some embodiments, the characterizing feature of the process of the present disclosure is addition of lime in about 5 batches until about 25% blowing.

In some embodiments of the present disclosure, the addition of lime in about 3 batches to 5 batches from about 0% blowing to 25% blowing is modified lime addition pattern in the process of producing low phosphorous steel.
In some embodiments of the present disclosure, first batch of the lime addition is carried out at about 0% blowing, wherein about 2000 kg to 4000 kg, including all the values in the range, for instance about 2001 kg, about 2002 kg, about 2003 kg, about 2004 kg and so on and so forth, is added.

In some embodiments of the present disclosure, second batch of the lime addition is carried out at about 5% blowing, wherein about 1000 kg to 2000 kg, including all the values in the range, for instance about 1001 kg, about 1002 kg, about 1003 kg, about 1004 kg and so on and so forth, is added.

In some embodiments of the present disclosure, third batch of the lime addition is carried out at about 10% blowing, wherein about 500 kg to 1500 kg, including all the values in the range, for instance about 501 kg, about 502 kg, about 503 kg, about 504 kg and so on and so forth, is added.

In some embodiments of the present disclosure, the fourth batch of the lime addition is carried out at about 20%, wherein about 500 kg to 1500 kg, including all the values in the range, for instance about 501 kg, about 502 kg, about 503 kg, about 504 kg and so on and so forth, is added.

In some embodiments of the present disclosure, the fifth batch of the lime addition is carried out at about 25 % blowing, wherein about 250 kg to 750 kg, including all the values in the range, for instance about 251 kg, about 252 kg, about 253 kg, about 254 kg and so on and so forth, is added.

The Figure 4 of the present disclosure describes addition of lime in about five batches (i. lime addition zero batch; ii. lime addition ignition batch; iii. 1st lime addition batch; iv. 2nd lime addition batch; and v. 3rd lime addition batch) until about 25% blowing. From the figure it can be observed that the lime addition was carried out at about 0% blowing, at about 5% blowing, at about 10% blowing, at about 20% blowing and at about 25% blowing, respectively. The inventors have identified that said modified lime addition pattern in the steel making process provides improvement in the turn down P% and percentage dephosphorization. The inventors also noted that adding lime in at about five batches until about 25% blowing improves lime dissolution and prevent patch and lumpy lime formation inside converter during initial blow period.

In some embodiments of the present disclosure, in the method of producing steel, the lime addition is reduced by about 12% when compared to conventional process of steel making in the basic oxygen furnace (BOF) process.

The inventors have identified that by reducing the addition of lime in the method of steel making reduces production cost of steel with reduction in unwanted solid steel making slag generation and reduction in free lime percentage in the final slag so that the slag can be employed for further applications without any pre-treatment.

In some embodiments, in the method of the present disclosure, about 25% to 50%, including all the values in the range, for instance, 26%, 27%, 28%, 29% and so on and so forth, of the slag is retained in the steel making process when compared to conventional steel making process.

The inventors have particularly identified that combination of – retaining about 25% to 50% slag in the steel making process and adding lime in about five batches until about 25% blowing provides for improved dephosphorization of steel when compared to conventional steel making process. It was observed that- by employing the said combination of steps in the method of the present disclosure, at least 23% phosphorous was reduced in the steel when compared to the conventional steel making process.

In some embodiments of the present disclosure, the lime comprises- CaO ranging from about 90% to 95%, MgO ranging from about 1% to 5%, SiO2, ranging from 0.5% to 3%, Al2O3 ranging from about 0.2% to 1.0%, FeO ranging from about 0.5% to 2%.

In some embodiments of the present disclosure, the lime has loss on ignition (LOI) ranging from about 2 to 3.

In some embodiments of the present disclosure, free lime in the slag is ranging from about 4% to 8%.

In some embodiments of the present disclosure, free lime in the slag is ranging from about 4%, about 5%, about 6%, about 7% or about 8%.

In some embodiments of the present disclosure, turndown or tapping temperature in the method is ranging from about 1620 ºC to 1680 ºC, including all the values in the range for instance, 1621 ºC, 1622 ºC, 1623 ºC, 1624 ºC and so on and so forth.

In some embodiments of the present disclosure, the method provides for dephosphorization ranging from about 90% to 95%.

In some embodiments of the present disclosure, the method provides for dephosphorization of about 90%, about 91%, about 92%, about 93%, about 94% or about 95%.

In some embodiments of the present disclosure, the phosphorus content in the hot metal is lowered from about 0.16% to 0.014%.

In some embodiments of the present disclosure, in addition to the above described, other input raw materials employed in the method are provided below-
i. Hot Metal: liquid iron is called hot metal, which comes from blast furnace. Hot metal contains several impurities, such as C, Si, P, Mn, Al, Ti and S. Hot metal which is in liquid form has temperature ranging from about 1200 ºC to 1400 ºC.
ii. Solid steel scrap: solid steel scrap in the primary coolant used for BOF process. Steel scrap is the combination of several varieties of scrap like, solid pig iron or pooled iron, tundish/lance Jam skull, mill return scrap, iron grain sort etc. Quantity of scrap depends on the various process inputs like, hot metal temperature, hot metal silicon, types of scrap and tapping temperature.
iii. Oxygen: Pure oxygen of about 99.5% was used as oxidant, which oxidises the impurities present in hot metal and from the oxide impurities present in hot metal. This oxide reacts with flux material, such as lime and forms liquid slag. The amount of oxygen required is dependent on the size of the convertor employed.

The method for producing low phosphorus steel from low silicon high phosphorus hot metal, described in the present disclosure provides for following advantages-
- Provides for effective dephosphorization of liquid iron or hot metal in BOF convertor.
- Provides for reduction in lime consumption, thereby conserving the lime material from exhaustion.
- Reduces free lime in slag. As a result, the slag can be used in other applications including but not limited to road making applications.
- Reduces the solid waste generation, such as steel making slag from steel plant.
- Reduces production cost of steel making
- Addresses the issue of lime dissolution by employing modified pattern of addition of lime in at least 3 batches until at least 25% blowing.
- Avoids the need of using synthetic slag or slag making materials in the process.

It is to be understood that the foregoing description is illustrative not a limitation. While considerable emphasis has been placed herein on 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.

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 may be practiced and to further enable those of skill in the art to practice the embodiments. Accordingly, following examples should not be construed as limiting the scope of the embodiments herein.

EXAMPLES
Example 1: Method of producing low phosphorous steel from low silicon high phosphorus hot metal.
160 T combined blown converter was used. After blow finish from previous heat, slag splashing was done and after that about 25% to 50% of the slag were retained inside the converter and remaining slag was dumped in slag pot. After dumping the slag, 3 T lime and 2 T raw dolomite was added at the bottom of the converter as zero batch and thereafter 18 T solid scrap was charged inside the converter and thereafter 152 T hot metal was charged, which was at about 1308 ºC temperature, which contains C % = 4.5, Si% = 0.33, P%= 0.17 and Mn= 0.05% then oxygen was supplied through the copper tip nozzle lance at the rate of about 27000 Nm3/hr. After the blowing was started, 1 T lime at ignition batch with 1 T raw dolomite was added after that remaining 3 T lime was added in three number of small batches till the 25 % of the blow. Blowing was done for total of about 17 minutes and during the oxygen blowing, iron ore was used as a coolant as per requirement and after the blow finish, sample and temperature was measured manually. The chemistry of the obtained liquid steel was -C% = 0.040, Si% = 0.001 and P% = 0.013. The method led to 92% dephosphorization rate and the liquid steel temperature was 1640 ºC.

Example 2: Method of producing low phosphorous steel from low silicon high phosphorus hot metal.
160 T combined blown converter was used. After blow finish from previous heat, slag splashing was done and after that about 25% to 50% of the slag were retained inside the converter and remaining slag was dumped in slag pot. After dumping the slag, 3 T lime and 2 T raw dolomite was added at the bottom of the converter as zero batch and thereafter 18 T solid scrap was charged inside the converter and thereafter 152 T hot metal was charged, which was at about 1308 ºC temperature, which contains C % = 4.5, Si% = 0.33, P%= 0.17 and Mn= 0.05% then oxygen was supplied through the copper tip nozzle lance at the rate of about 27000 Nm3/hr. After the blowing was started, 1 T lime at ignition batch with 1 T raw dolomite was added after that remaining 3 T lime was added in four number of small batches till the 25 % of the blow. Blowing was done for total of about 17 minutes and during the oxygen blowing, iron ore was used as a coolant as per requirement and after the blow finish, sample and temperature was measured manually. The chemistry of the obtained liquid steel was -C% = 0.040, Si% = 0.001 and P% = 0.014. The method led to 91.8% dephosphorization rate and the liquid steel temperature was 1645 ºC.

Example 3 (Comparative Example): Method of producing steel from low silicon high phosphorus hot metal using conventional BOF process.
160 T combined blown converter was used for the invention. After blow finish from previous heat, slag splashing was done and after that about 10% to 25% of the total slag was retained inside the converter and remaining slag is dumped in slag pot. After dumping the slag, 3 T lime and 2 T raw dolomite was added at the bottom of the converter as zero batch and thereafter 17 T solid scrap was charged inside the converter and thereafter 153 T hot metal was charged, which was at 1311 ºC temperature, which contains C % = 4.4, Si% = 0.36, P%= 0.16 and Mn= 0.04% then oxygen was supplied through the copper tip nozzle lance at the rate of 27000 Nm3/hr. After the blowing was started, 1 T lime at ignition batch with 1 T raw dolomite was added after that remaining 3 T lime was added in one batch within 10 % of blow. The blowing was done for total of about 17 minutes and during the oxygen blowing, iron ore was used as a coolant as per requirements and after the blow finish, sample and temperature was measured manually. The chemistry of liquid steel obtained was- C% = 0.045, Si% = 0.002 and P% = 0.017. The method led to 89.5 % dephosphorization rate and the liquid steel temperature was 1645 ºC

Discuss of Example 1/2 and Example 3 (Comparative Example)
From the experiment under Example 1/2, it can be observed that retaining slag at about 25% to 50% in the process and adding lime in at least three batches until 25% of blow provides for improved dephosphorization rate of about 92% or 91.8% and the phosphorous content in the liquid steel was about 0.013% or 0.014%.

From the experiment under Example 3 (Comparative Example), it can be observed that retaining slag at about 10% to 25% in the process and adding lime in one batch until 10% of blow provides for dephosphorization rate of about 89% and the phosphorous content in the liquid steel was about 0.017.

Thus, it can be observed that in the method of the present disclosure by retaining about 25% to 50% of slag and adding lime in at least three batches until at least 25% blow provides for improved dephosphorization rate and reduces the phosphorous in the produced steel by at least 23%.

Example 4: Method of producing steel
Under this Example, the method was carried out with about 12% reduction in the addition of lime when compared to the experiment conducted under Example 3 (Comparative Example).
The Table 1 below illustrates the process parameters and output obtained.
Process Parameters Conventional Process:
(Normal addition of lime) Method with 12% reduction in lime addition)
Number of trial heats 180 86
Avg. HM Temp (Degree C) (SD) 1309(28) 1320(26)
Avg. HM Si %(SD) 0.40(0.05) 0.41(0.04)
Avg. HM P %(SD) 0.16(0.009) 0.16(0.010)
Avg. HM Si/P ratio (SD) 2.5(0.29) 2.6(0.28)
Avg. TD P%(SD) 0.016(0.004) 0.016(0.004)
Avg. % Dephos (SD) 90.5(2.5) 90.3(2.7)
Avg. TD Temp (SD) 1634(19.6) 1637(16.2)
Avg. TD slag Basicity (SD) 3.8(0.05) 3.4(0.04)
Avg. TD Total slag Fe% (SD) 16.7(2.4) 16.4(2.3)

Table 1:
The data in Table 1 shows that 12% reduction in lime addition when compared to conventional process decreased the slag basicity from 3.8 to 3.4. Thus, it means that addition of extra 12% of lime for the same hot metal chemistry only increased the undissolved lime or unreacted lime in the final slag (slag basicity) in the conventional process.

Example 5: Method of producing steel
Under this example, the method was carried out with adding lime according to modified lime addition pattern (at least in 3 batches till 25% blowing). The process parameters and output are provided in Table 2.
Process Parameters Conventional Process:
(Normal lime addition pattern) Method with Modified lime addition pattern
Number of trial heats 25 25
Avg. HM Temp (Degree C) (SD) 1336(28) 1318(26)
Avg. HM Si %(SD) 0.43(0.05) 0.44(0.04)
Avg. HM P %(SD) 0.16(0.009) 0.16(0.010)
Avg. HM Si/P ratio (SD) 2.6(0.29) 2.7(0.28)
Avg. TD P%(SD) 0.017(0.004) 0.014(0.004)
Avg. % Dephos (SD) 90.0(2.5) 93.2(2.7)
Avg. TD Temp (SD) 1642(19.6) 1640(16.2)
Avg. TD slag Basicity (SD) 3.4(0.04) 3.3(0.05)
Avg. TD Total slag Fe% (SD) 16.5(2.1) 16.4(2.5)

Table 2:
The data in Table 2 shows that- addition of lime in the process in at least three batches until at least 25% blow provides for about 93.2% dephosphorization rate (improved dephosphorization) when compared to 90% dephosphorization rate when lime is added in one batch until 10% blow (normal addition pattern).

The foregoing description of the specific embodiments reveal 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 generic 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.

Throughout this specification, the term ‘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 patents disclosures.

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.