Refractory lining material for iron-making

Abstract

The present invention relates to refractory lining material employed in the metallurgical industry, more specifically, magnesia carbon refractory lining material for electrothermal furnaces in the upstream iron-making process. A process for the smelting of a metalliferous-containing feedstock, the process comprising the steps: i) feeding a metalliferous-containing feedstock material, reductant and fluxes into an electrothermal furnace to form at least one pile arrangement, wherein the electrothermal furnace includes refractory lining material comprising MgO-C, and wherein the refractory lining material has a thermal conductivity above 5 W / mK; ii) heating the pile arrangement in the electrothermal furnace at a temperature of between 1 400°C to 1 700°C to sufficiently melt the pile arrangement to form a liquid metal product, a liquid slag product and a CO-containing gas; iii) carburising the metal product by introducing a source of carbon into the electrothermal furnace; and iv) ensuring the continuous feeding of the metalliferous-containing feedstock material, reductant and fluxes into the electrothermal furnace to preserve the at least one pile arrangement.

Description

[0001] REFRACTORY LINING MATERIAL FOR IRON-MAKING

[0002] FIELD OF APPLICATION OF THE INVENTION

[0003] The present invention relates to refractory lining material employed in the metallurgical industry, more specifically, magnesia carbon refractory lining material for electrothermal furnaces in the upstream iron-making process.

[0004] BACKGROUND TO THE INVENTION

[0005] Electric arc furnaces (EAFs) and ladle furnaces both serve as indispensable components in the metallurgical sector, primarily driving steel production. These furnaces harness the power of an electric arc, initiated by an electric charge moving through graphite electrodes, to proficiently melt the charge material. Given that these furnaces often attain temperatures in excess of 1 700°C, the selection of the appropriate refractory lining material becomes a paramount concern.

[0006] Historically, magnesia carbon (MgO-C), and magnesia (MgO) bricks have been used for fortifying the sidewalls of EAFs tailored for steel-making. Their pivotal role extends to ladle furnaces as well, where they remain instrumental in ensuring the steel's desired composition and quality. Yet, they are not impervious to challenges. The carbon integral to their composition is exposed to oxidation risks, especially in environments with elevated oxygen concentrations. While carbon bolsters their thermal shock resistance, it doesn’t immunise them against fractures arising from sudden temperature shifts. In ladle furnaces, where steel undergoes secondary refining, and the slag's composition can be distinctly different from that in EAFs, these bricks can experience exacerbated wear. This ever-shifting composition of slag intensifies its interaction with refractory materials, sometimes leading to accelerated wear or chemical degradation.

[0007] Drawing from the vast reservoir of knowledge on refractory lining materials for steel-making EAFs, it's evident that transitioning this expertise to encompass iron-making is riddled with complexities. The kaleidoscope of slag compositions, intricate temperature dynamics, and the nuances of operational procedures imply that there is a plethora of factors to be considered to allow for commonly used refractory lining bricks to be used for iron-making.

[0008] Thus, arises the pressing need for devising refractory lining material attuned to the unique demands of electrothermal furnaces in iron-making, amalgamating age-old wisdom to suit iron-making conditions.

[0009] For purposes of the present specification, it will be appreciated that the following acronyms are used synonymously with the below referenced phrases:

[0010] EAF Electric Arc Furnace

[0011] BF Blast Furnace

[0012] CBI Cold Briquetted Iron

[0013] CDRI Cold Direct Reduced Iron

[0014] DCF Direct Current Furnace

[0015] DRI Direct Reduced Iron

[0016] HBI Hot Briquetted Iron

[0017] HDRI Hot Direct Reduced Iron

[0018] OBF Open Bath Furnace

[0019] OSBF Open Slag Bath Furnace

[0020] SAF Submerged Arc Furnace

[0021] MgO-C Magnesia Carbon (or Magnesia Graphite) It will be appreciated that the processes described in Dutch Priority Founding Patent Application No. N2034821 and in Dutch Priority Founding Patent Application No. N2034822 are both to be incorporated herein by reference.

[0022] OBJECT OF THE INVENTION

[0023] Accordingly, it is an object of the present invention to provide refractory lining material tailored for electrothermal furnaces in the iron-making process. More specifically, the invention seeks to provide refractory lining material that mitigates the vulnerabilities of existing linings, particularly in relation to oxidation, thermal shocks, and the evolving compositions of slag, ensuring enhanced durability and operational efficiency.

[0024] SUMMARY OF THE INVENTION

[0025] According to a first aspect of the present invention, there is provided a process for the smelting of a metalliferous-containing feedstock, the process comprising the steps: i) feeding a metalliferous-containing feedstock material, reductant and fluxes into an electrothermal furnace to form at least one pile arrangement, wherein the electrothermal furnace includes refractory lining material comprising MgO-C; ii) heating the pile arrangement in the electrothermal furnace at a temperature of between 1 400°C to 1 700°C to sufficiently melt the pile arrangement to form a liquid metal product, a liquid slag product and a CO-containing gas; iii) carburising the metal product by introducing a source of carbon into the electrothermal furnace; and iv) ensuring the continuous feeding of the metalliferous-containing feedstock material, reductant and fluxes into the electrothermal furnace to preserve the at least one pile arrangement. Smelting in the present context is to be understood as the process of extracting iron from a metalliferous-containing feedstock material.

[0026] Pile in the present context is to be understood as a collection of materials laid on top of one another and stacked substantially vertically.

[0027] It will be appreciated that the metalliferous-containing feedstock material may be any material, such as unreduced ore, pre-reduced ore, scrap, concentrate, or any combination of such materials, which material or combination of materials comprise a metal or metalcontaining compound of iron (Fe).

[0028] In an embodiment of the invention, the metalliferous feedstock material may be either hot, cold or a combination of hot and cold metalliferous-containing feedstock material, which may be fed into the reactor.

[0029] The invention may provide for a plurality of adjustable feeding chutes which allow for the introduction of the combination of hot and cold metalliferous-containing feedstock material into the electrothermal furnace.

[0030] The metalliferous-containing feedstock material may be either pre-reduced metalliferous- containing feedstock material or un-reduced metalliferous-containing feedstock material, which may be pre-reduced iron ore or un-reduced iron ore, respectively.

[0031] The pre-reduced iron ore may be selected from the group consisting of hot briquetted iron (HBI), wherein the HBI may be crushed to HBI D5o < 20 mm; cold DRI (CDRI); and hot DRI (HDRI). The metalliferous-containing feedstock material may include cold briquetted iron waste (CBI D5o < 20mm).

[0032] The metalliferous-containing feedstock material may include waste fines (D5o < 20 mm); mill scale (D5o < 10mm); pre-reduced iron ore fines (D5o < 10 mm); un-reduced iron ore fines (D5o < 10 mm); and a combination thereof.

[0033] In an embodiment of the invention, the pre-reduced iron ore may be carbon-deficient or carbon-free HBI, CDRI or HDRL It will be appreciated that the pre-reduced iron ore may be low Fe grade HBI, CDRI or HDRL

[0034] In a further embodiment of the invention, the pre-reduced iron ore can include recycled scrap.

[0035] The invention provides for low-grade HBI or cold or hot DRI to also be produced with 100% hydrogen to further reduce the carbon footprint. It will be appreciated that the HBI or DRI produced with 100% hydrogen will have a very low to 0% carbon content.

[0036] It will be appreciated that where HDRI is not available, the invention provides for pre-heating the HBI and CDRI in an inert atmosphere and fed into the electrothermal furnace.

[0037] Thus, in an embodiment of the present invention, the electrothermal furnace may include a pre-heating system to pre-heat the HBI or CDRI to the required temperatures to be fed into the electrothermal furnace to improve electrical efficiency.

[0038] The invention provides for continuous replenishment of the metalliferous-containing feedstock material, reductant and fluxes into the electrothermal furnace to ensure that at least one pile arrangement is preserved. It will be appreciated that the loss-in-weight and power-to-feed balance are integral here.

[0039] The specific energy requirement (SER) of a smelting process can be simply expressed as MWh per metric ton of total power to feed (MW) / feed rate (ton / h). SER is the energy required to transform the feed materials at ambient temperature into the product streams at the desired temperatures at which they leave the furnace. SER is thus inherently the power-to- feed ratio. It will be appreciated that the theoretical SER changes quite significantly if the chemical composition or temperature of the raw materials deviates from the theoretical baseline.

[0040] It is to be understood that an electrothermal furnace is a furnace with a heat source derived from electricity. The electrothermal furnace may be either a direct current (DC) electrothermal furnace, or an alternating current (AC) electrothermal furnace, wherein the electrothermal furnace may be used in open bath smelting (open bath furnace (OBF)).

[0041] In terms of the present invention, the OBF may be operated on different arc modes, namely immersed arc mode, brush arc mode and short open arc mode.

[0042] In an embodiment of the invention, there is provided for the electrothermal furnace to include an insulated copper or steel roof.

[0043] The invention provides for the OBF to be a circular-shaped furnace. In an alternative embodiment of the invention, the OBF may be a rectangular-shaped furnace.

[0044] In terms of the invention, the electrothermal furnace has a power capacity of up to 120 MW with a typical 580 - 640 kWh / ton of hot metal and typical reductant usage of 40 - 60 kg / ton of hot metal (Aim 2.0 to 4.5 %C). A SER higher than this value is possible if the metalliferous- containing feedstock is of lower grade than blast furnace grade pellets.

[0045] In an embodiment of the invention, the DC electrothermal furnace may have at least a single electrode. The AC electrothermal furnace may have at least three electrodes.

[0046] In an embodiment of the invention, the plurality of adjustable feeding chutes for introducing the hot and cold metalliferous-containing feedstock may comprise a single feeder connected to each feeding cute.

[0047] The invention provides for the reductant to be a low-grade reductant, for instance, anthracite, finer fraction coke, or petroleum coke. The reductant may be added to the electrothermal furnace as particulates having a particle size equal to or less than 0 to 50 mm.

[0048] The flux may be selected from the group consisting of burnt dolomite, burnt limestone, quartzite, bauxite and a combination of one or more thereof.

[0049] In terms of the invention, the liquid metal product material may be formed through the heating and melting or at least partial melting of the metalliferous-containing feedstock material, reductant and fluxes.

[0050] The residence time of the metalliferous-containing feedstock material in the electrothermal furnace may be controlled to impact the degree of reduction of the iron-containing feedstock material in the electrothermal furnace.

[0051] The step of feeding the metalliferous-containing feedstock material into the electrothermal furnace may be preceded by a step of pelletising the metalliferous-containing feedstock material. The pelletisation may be done at a pelletiser facility. In terms of the invention, the slag product may be used downstream in inter alia cement applications.

[0052] The degree of metallisation of iron in the iron-containing feedstock material in the process may be from 86% up to 94%.

[0053] It will be appreciated that carburisation involves taking a low-carbon metal product and transforming it into a high-carbon metal product. This may be done by exposing the metal product to an atmosphere which is dense in carbon. By heating a metal product in a carbon- dense atmosphere, the metal product will allow carbon atoms to attach to its surface on a molecular level.

[0054] In terms of the present invention, carburisation may be achieved by carbon lancing in the electrothermal furnace into the hot metal. In an alternative embodiment of the invention, carburisation may be achieved in a Torpedo or a suitable-type vessel.

[0055] In an embodiment of the invention, there is provided for carbon lances to be included in the electrothermal furnace to introduce carbon into the electrothermal furnace to facilitate the carburisation of the metal product, if necessary.

[0056] The hot metal product is characterized as:

[0057] The invention provides for the net carbon footprint to be between 20% and 40% of the traditional BF route.

[0058] In an embodiment of the invention, the refractory lining material may, preferably, have the following composition:

[0059] Further preferably, the refractory lining material may have the following composition:

[0060] In an embodiment of the invention, the refractory lining material may include additives selected from the group consisting of Al, Si, Mg metal powders, and a combination thereof.

[0061] Preferably, the additives may be Al and Si metal powder. In an embodiment of the invention, the refractory lining material aids in protecting the electrothermal furnace to limit the effects of corrosion on inner walls of the electrothermal furnace. It will be appreciated that the rate of corrosion in terms of the present invention may be between 42% and 62% based on finger tests that were executed.

[0062] The inclusion of carbon in the refractory lining material may limit corrosion to between 9- 14% wear area and 16 - 26% wear depth based on finger tests that were executed. Preferably, the wear area and wear depth will be limited to 9% and 16%, respectively.

[0063] In an embodiment of the invention, the inclusion of carbon in the refractory lining material in conjunction with a shell-cooling system may aid in the formation of a slag freeze-lining on the refractory bricks that further limits corrosion. This may limit the wear depth in the wear area to below 10% based on dig-out results from pilot-scale test work on a 1 MW furnace that utilised the refractory lining material and the process disclosed herein.

[0064] In an embodiment of the invention, the refractory lining material may aid to impede the composition change of the liquid slag to limit the dissolution of MgO, CaO, and dilution of SiC>2 and AI2O3 to between 0 - 16%, 0 - 5%, 0 - 5%, 0 - 12% change as opposed to where the refractory lining material of the present invention was not utilised in the electrothermal furnace.

[0065] In a preferred embodiment of the invention, the dissolution of MgO and AI2O3 in the liquid slag and the dilution of the liquid slag may be between 0 - 8%, 0 - 12%, -2 - 0%, and -3 - 0%, respectively.

[0066] The refractory lining material may have a porosity, measured as an open pore size, of between 1 % and 11 %. Preferably, the open pore size will be limited to 2%.

[0067] It is to be appreciated that by having such a low porosity, the electrothermal furnace walls will demonstrate improved protection against the corrosive effects of the liquid slag to prolong the lifespan of the electrothermal furnace. Moreover, it will increase the overall yield of the process.

[0068] The refractory lining material may have a thermal conductivity above 5 W / mK that will improve conductive heat exchange from the shell cooling mechanism that will subsequently lower the surface temperature of the hot face of the refractory lining material to below the liquidus temperature of the liquid slag. This will promote the formation of a slag freeze lining of sufficient thickness to improve protection against the corrosive effects of liquid slag and mechanical wear from bath movement.

[0069] The present invention provides a multi-physical computational fluid dynamics model for the reactions, kinetics, and different transformer modes with specific reference to the OBF.

[0070] It will be appreciated that post-tap hole operations can be integrated seamlessly into the process of the present invention.

[0071] It is to be understood that the steps of the process according to the invention need not necessarily be executed sequentially, as the process may be operated in a batch, semi- batch or continuous manner. Furthermore, it is envisaged that the steps of the process provided for need not necessarily be executed in the order listed herein.

[0072] According to a second aspect of the invention, there is provided use of refractory lining material, as substantially described herein according to the first aspect of the invention, in DC OBF and AC OBF operations.

[0073] The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrates, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

[0074] BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Preferred embodiments of the invention are described below with reference to the accompanying figures, wherein:

[0076] Figure 1 depicts both a perspective view of a refractory lining material test sample used in the finger test experiment and a sectional perspective view of a high-frequency induction furnace used to conduct the experiment according to the process of the present invention;

[0077] Figure 2 depicts a table setting out the composition of metal product and liquid slag, respectively;

[0078] Figure 3 depicts a table setting out the refractory lining material finger test samples, the composition, and the test order;

[0079] Figure 4 depicts top views of the refractory lining material finger test samples preexperiment, demonstrating visually how the samples appeared prior to being exposed to the experimental conditions;

[0080] Figure 5 depicts a top view of the refractory lining material finger test samples after the experiment’s conclusion;

[0081] Figure 6 depicts ternary composition diagrams of the modelled slag composition;

[0082] Figure 7 depicts a graph showing a comparative analysis of the wear depth and wear area for the respective refractory lining material finger test samples; Figure 8 depicts a graph demonstrating a comparative analysis of the change in slag composition for the respective refractory lining material finger test samples;

[0083] Figure 9 depicts the porosity of the various unused refractory lining material finger test samples;

[0084] Figure 10 depicts the gas permeability and porosity of the unused refractory lining material finger test samples;

[0085] Figure 11 depicts the micro-X-ray fluorescence sulphur finger test results for the respective refractory lining material test samples after the experiment has been conducted;

[0086] Figure 12 depicts the schematic layout of the different refractory lining material that was utilised in the pilot scale 1 MW furnace test work;

[0087] Figure 13 depicts the results from a 3D scan analysis of the 1 MW pilot scale furnace, showing the original refractory lining material, the build-up of material / slag freeze lining and the corroded refractory lining material of the completion of the test campaign for MgO-C and MgO refractory lining material;

[0088] Figure 14 depicts the results from a 3D scan analysis of the 1 MW pilot scale furnace, showing the original refractory lining material, the build-up of material / slag freeze lining and the corroded refractory lining material at the end of the test campaign for MgO-Cr2O3 refractory lining material;

[0089] Figure 14 depicts the results from a 3D scan analysis of the 1 MW furnace showing the original refractory lining material, the build-up of material / slag freeze lining and the corroded refractory lining material at the end of the test campaign for MgO- Cr2O3 refractory lining material; and

[0090] Figure 15 depicts back scattered electron (BSE) images from a scanning electron microscope (SEM) analysis that was executed on MgO-C refractory lining material after the 1 MW pilot-scale test work; and

[0091] Figure 16 depicts a post-mortem mineralogical analysis of the MgO-C refractory lining material with minimal wetting of the MgO-C refractory lining material after the 1 MW pilot-scale test.

[0092] The presently disclosed subject matter will now be described more fully hereinafter with reference to the accompanying description of the preferred embodiment of the present invention, in which representative embodiments are shown. The presently disclosed subject matter can, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the embodiments to those skilled in the art.

[0093] DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0094] A non-limiting example of a preferred embodiment of the invention is described in more detail below, with reference to Figures 1 and 15.

[0095] An array of refractory lining materials was tested for durability, corrosive resistance, and lifespan in order, as set out in Figure 3.

[0096] The refractory lining material test samples were finger tested in an electrothermal furnace, more specifically a high-frequency induction furnace, as depicted in Figure 1.

[0097] The finger test experiments yielded a metal composition and slag composition, as exemplified in Figure 2. The experiment was conducted under the following constraints and conditions:

[0098] The results of the finger test experiment, which compares the durability, corrosive resistance, porosity, gas permeability, and thermodynamic composition diagrams are further depicted in Figures 4 to 11.

[0099] Figure 7 and Figure 8 illustrate the superior performance of the MgO-C refractory lining material of the present invention. Moreover, despite MgO-C showing a noticeable corrosion rate, the carbon and antioxidants (such as aluminium metal and silicon metal) are added to protect the microstructure against high infiltration and wetting of the MgO if the process conditions are favourable.

[0100] Figure 8 depicts the liquid slag product’s composition change for the finger tests, showing the oxide concentration at the beginning of the test in the slag vis-a-vis the oxide concentration at the end of the test in the liquid slag product. MgO-C and MgO qualities demonstrate noticeable MgO dissolution and SiO2, and CaO dilution; however, the protection offered by the antioxidants and carbon non-wettability resulted in an overall low wear profile.

[0101] Figure 9 represents the porosity of the various refractory lining material finger test samples and shows that the smallest pores are present in MgO-C refractory lining material test samples.

[0102] Similar results can be shown in Figure 10, which depicts the gas permeability, whereby the MgO-C outperforms the other refractory lining material test samples by having very low gas permeability.

[0103] Figure 1 1 depicts the deposition of sulphur on the refractory lining material finger test samples and demonstrates the micro-X-ray fluorescence test results showing less sulphur deposition on the MgO-C refractory lining material test samples.

[0104] Figure 12 shows the layout of the refractory lining material that was installed in the working area (lower half) of a 1 MW pilot-scale test furnace that was continuously operated for 31 days. The process, as described herein, was implemented; slag and metal were produced and intermittently tapped from the furnace. The SER, as specified herein, was implemented along with a furnace shell cooling design specific to the OBF. It will be appreciated that the results of the refractory corrosion of this furnace are therefore representative of what can be expected in real-life applications (commercial scale). Figure 13 and Figure 14 illustrate scans that were executed of the furnace after the test work. The MgO-Cr2O3 refractory lining material showed excessive corrosion and no slag-freeze lining built up. The MgO refractory lining material also showed excessive corrosion and minimal slag-freeze lining built up. The MgO-C refractory lining material showed minimal corrosion and a slag-freeze lining built up.

[0105] Figure 15 illustrates a profile of the MgO-C refractory lining material section from the 1 MW pilot-scale tests that shows that there was no significant corrosion of the refractory lining material. A layer of slag-freeze lining formed on the bricks that assisted in the protection of the refractory lining material from the corrosive effects of the liquid slag. The heaps that formed during test work are also illustrated, showing how they were encapsulated in slag during draining of the furnace at the end of the test campaign.

[0106] Figure 16 shows a post-mortem mineralogical analysis of MgO-C refractory lining material after the 1 MW pilot-scale test, confirming that there was minimal wetting of the bricks (penetration of slag into the pores).

[0107] It is, of course, to be appreciated that the refractory lining material for iron-making in accordance with the present invention is not limited to the precise constructional and functional details as hereinbefore described with reference to the accompanying figures and which may be varied as desired.

[0108] Although only certain embodiments of the invention have been described herein, it will be understood by any person skilled in the art that other modifications, variations, and possibilities of the invention are possible. Such modifications, variations and possibilities are therefore to be considered as falling within the spirit and scope of the invention and hence form part of the invention as herein described and / or exemplified. It is further to be understood that the examples are provided for illustrating the invention further and to assist a person skilled in the art with understanding the invention and are not meant to be construed as unduly limiting the reasonable scope of the invention.

[0109] The Applicant believes that the refractory lining material for iron-making, more specifically for electrothermal furnaces directed towards iron-making in accordance with the present invention, is advantageous in that it offers superior resistance to oxidation, can withstand extreme thermal shocks, and adaptively responds to the changing compositions of slag, thereby ensuring extended longevity, heightened durability, and improved operational efficiency of such electrothermal furnaces.

Claims

CLAIMS1 . A process for the smelting of a metalliferous-containing feedstock, the process comprising the steps: i) feeding a metalliferous-containing feedstock material, reductant and fluxes into an electrothermal furnace to form at least one pile arrangement, wherein the electrothermal furnace includes refractory lining material comprising MgO-C, and wherein the refractory lining material has a thermal conductivity above 5 W / mK; ii) heating the pile arrangement in the electrothermal furnace at a temperature of between 1 400°C to 1 700°C to sufficiently melt the pile arrangement to form a liquid metal product, a liquid slag product and a CO-containing gas; iii) carburising the metal product by introducing a source of carbon into the electrothermal furnace; and iv) ensuring the continuous feeding of the metalliferous-containing feedstock material, reductant and fluxes into the electrothermal furnace to preserve the at least one pile arrangement.

2. The process according to claim 1 , wherein the metalliferous-containing feedstock material comprises a metal or metal-containing compound of iron (Fe).

3. The process according to claim 2, wherein the metalliferous feedstock material is either hot, cold or a combination of hot and cold metalliferous-containing feedstock material, which may be fed into the reactor.

4. The process according to claim 2 or claim 3, wherein the metalliferous-containing feedstock material is either pre-reduced metalliferous-containing feedstock material or un-reduced metalliferous-containing feedstock material, which may be pre-reduced iron ore or un-reduced iron ore, respectively.

5. The process according to claim 1 , wherein the electrothermal furnace is either a direct current (DC) electrothermal furnace, or an alternating current (AC) electrothermal furnace, wherein the electrothermal furnace is used in open bath smelting (open bath furnace (OBF)).

6. The process according to claim 5, wherein the OBF is operated on different arc modes, namely immersed arc mode, brush arc mode and short open arc mode.

7. The process according to claim 1 , wherein the electrothermal furnace has a power capacity of up to 120 MW with a typical 580 - 640 kWh I ton of hot metal and typical reductant usage of 40 - 60 kg / ton of hot metal (Aim 2.0 to 4.5 %C).

8. The process according to claim 1 , wherein the refractory lining material has the following composition:

9. The process according to claim 8, wherein the refractory lining material has the following composition:

10. The process according to any one of claims 1 , 8 or 9, wherein the refractory lining material includes additives selected from the group consisting of Al, Si, Mg metal powders, and acombination thereof.11 . The process according to claim 10, wherein the additives are at least one of Al metal powder and Si metal powder.

12. The process according to any one of claims 8 to 11 , wherein the refractory lining material aids in protecting the electrothermal furnace to limit the effects of corrosion on inner walls of the electrothermal furnace.

13. The process according to claim 12, wherein the rate of corrosion is between 42% and 62% based on finger tests that were executed.

14. The process according to any one of claims 8 to 13, wherein inclusion of carbon in the refractory lining material limits corrosion to between 9 - 14% wear area and 16 - 26% wear depth based on finger tests that were executed.

15. The process according to claim 14, wherein the wear area and wear depth are limited to 9% and 16%, respectively.

16. The process according to any one of claims 8 to 15, wherein inclusion of carbon in the refractory lining material in conjunction with a shell-cooling system aids in the formation of a slag freeze-lining on the refractory bricks that further limits corrosion.

17. The process according to claim 16, wherein the wear depth in the wear area is limited to below 10% based on dig-out results from pilot-scale test work on a 1 MW.

18. The process according to any one of claims 8 to 17, wherein the refractory lining material aids to impede the composition change of the liquid slag to limit the dissolution of MgO, CaO, and dilution of SiC>2 and AI2O3 to between 0 - 16%, 0 - 5%, 0 - 5%, 0 - 12% change as opposed to where the refractory lining material was not utilised in the electrothermal furnace.

19. The process according to claim 18, wherein the dissolution of MgO and AI2O3 in the liquidslag and the dilution of the liquid slag is between 0 - 8%, 0 - 12%, -2 - 0%, and -3 - 0%, respectively.

20. The process according to any one of claims 8 to 19, wherein the refractory lining material has a porosity, measured as an open pore size, of between 1% and 11 %.21 . The process according to claim 20, wherein the open pore size is limited to 2%.

22. The process according to claim 1 , wherein the thermal conductivity of the refractory lining material lowers the surface temperature of a hot face of the refractory lining material below the liquidus temperature of the liquid slag to promote the formation of a slag freeze lining of sufficient thickness to aid in impeding the corrosive effects of the liquid slag and mechanical wear from the bath movement of the electrothermal furnace.

23. The process according to claim 1 , wherein the reductant is a low-grade reductant selected from the group consisting of anthracite, finer fraction coke, or petroleum coke and a combination thereof, and wherein the reductant is added to the electrothermal furnace as particulates having a particle size equal to or less than 50 mm.

24. The process according to claim 1 , wherein the flux is selected from the group consisting of burnt dolomite, burnt limestone, quartzite, bauxite and a combination of one or more thereof.

25. The process according to claim 1 , wherein the degree of metallisation of iron in the iron- containing feedstock material in the process may be from 86% up to and including 94%.

26. The process according to claim 1 , wherein the electrothermal furnace provides carbon lances to introduce carbon into the electrothermal furnace to facilitate the carburisation of the metal product.

27. The process according to claim 1 , wherein the hot metal product is characterised as:

28. The process according to any one of the preceding claims, wherein the process has a net carbon footprint between 20% and 40% of a traditional blast furnace route.

29. Use of a refractory lining material according to any one of claims 1 to 28, in a direct current open bath furnace or an alternating current open bath furnace.

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