NL2030140B1

NL2030140B1 - Ferroalloy smelting process

Info

Publication number: NL2030140B1
Application number: NL2030140A
Authority: NL
Inventors: Petrus Greyling Frederik
Original assignee: Petrus Greyling Frederik
Priority date: 2021-12-15
Filing date: 2021-12-15
Publication date: 2023-06-27
Also published as: AU2022224740A1

Abstract

The invention pertains to a ferroalloy smelting process that utilizes carbon of tyre-char as reducing agents. The tyre-char is obtained by subjecting scrap or discarded tyres to a pyrolysis reaction. The ferroalloy smelting process is performed in an electric arc furnace. The electric arc furnace may be any one of brush-arc furnace (10), a DC-arc furnace and a submerged-arc furnace. The carbon of the tyre-char fed to the electric arc furnace binds with an oxygen atom of a ferrous metal oxide that forms part of a ferroalloy feedstock solid fed to a burden (12) of the electric arc furnace to reduce an oxidation state of the ferrous metal oxide.

Description

FERROALLOY SMELTING PROCESS

FIELD OF THE INVENTION

The invention pertains to a ferroalloy smelting process. More particularly, the invention pertains to a ferroalloy smelting process that utilizes carbon from tyre-char as reducing agents.

BACKGROUND TO THE INVENTION

A metal is typically extracted from its ore by means of a smelting process. During a smelting process, heat together with a chemical reducing agent (that is, a reductant) reduces a metal oxide in the ore to release oxygen bound to the metal. The oxygen that is released from the metal oxide binds to carbon to form a carbon monoxide (CO) off-gas.

The chemical reducing agent used conventionally in a smelting process is a fossil fuel source of carbon. The fossil fuel source of carbon is typically coke, char, anthracite or metallurgical grade coal.

The ferroalloy smelting industry is under pressure to minimise its impact on the environment.

One way by which the ferroalloy smelting industry may achieve this is by reducing its dependence on fossil fuel sources of carbon.

The applicant is aware of smelting processes that utilizes scrap or discarded tyres as a fuel source. A typical scrap or discarded tyre comprises, by weight, about 70% recoverable rubber, 15% steel, 3% fibres and 12% extraneous material (for example, inert fillers). The recoverable rubber contains approximately 75% to 85%, by weight, carbon. It is this high percentage of combustible carbon in the recoverable rubber that permits discarded or scrap tyres to be used as a fuel source in smelting processes.

The high percentage of combustible carbon may, however, also pose a risk as the carbon may combust uncontrollably in a furnace to which it is fed. Furthermore, volatiles present in the scrap or discarded tyres may cause high off-gas volumes to form in a furnace to which it is fed.

The high volatile level also results in a lower energy efficiency of the furnace to which the scrap or discarded tyres are fed.

United States of America patent numbers US 8,470,069 B2 and US 7,674,317 B2 describe processes whereby scrap tyres are used as an energy source in an electric arc furnace. In these processes, the scrap tyres are combusted as an energy source to provide heat in the furnaces to which it is fed. The heat generated by the combustion of the scrap tyres are used in combination with electric energy to smelt metal oxides in the electric arc furnaces.

The above notwithstanding, the vast majority of scrap or discarded tyres still end up in landfills and pose a major environmental risk. Amongst other things, scrap or discarded tyres pose a significant fire hazard with associated air and water pollution. Furthermore, scrap or discarded tyres provide a breeding ground for mosquitoes and toxic chemicals from the scrap or discarded tyres may leach into ground water.

Thus, there remains a need for the ferroalloy smelting industry to reduce its reliance on fossil fuel sources of carbon. Furthermore, new and inventive uses of scrap or discarded tyres are needed to minimize the detrimental environmental and health risks which these tyres pose in a landfill.

OBJECT OF THE INVENTION

It is an object of the present invention to provide a ferroalloy smelting process that utilizes carbon from tyre-char as reducing agents to at least reduce the ferroalloy smelting industry’s dependence on and use of fossil fuel sources of carbon.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a ferroalloy smelting process including the steps of: — feeding ferroalloy feedstock solids to a burden that locates in a chamber of an electric arc furnace, the burden comprising at least a liquid metal product, a liquid slag product and ferroalloy feedstock solids dispersed therein; — feeding tyre-char that includes carbon to the burden; — energizing electrodes of the electric arc furnace to create electric arcs that heat the burden and melt the ferroalloy feedstock solids and tyre-char in the burden; and — reducing ferrous metal oxides that form part of the ferroalloy feedstock solids, to form a liquid metal that reports to the liquid metal product and a liquid slag that reports to the liquid slag product, wherein the carbon of the tyre-char fed to the burden acts as a reducing agent to decrease an oxidation state of the ferrous metal oxides that form part of the ferroalloy feedstock solids fed to the burden.

It will be appreciated by the person skilled in the art that the term “ferroalloy”, as used herein, includes a broad range of iron-carbon alloys and other iron-carbon and/or iron-based alloys, including ferrochromium, ferrochromium silicon, ferromanganese, ferrosilicon manganese, ferrosilicon, magnesium ferrosilicon, ferromolybdenum, ferronickel, ferrotitanium, ferrophosphorus, ferrotungsten, ferrovanadium, ferrozirconium, etc.

It will further be appreciated by the person skilled in the art that the term “ferroalloy feedstock”, as used herein, includes any raw material from which a ferroalloy may be produced. Examples of ferroalloy feedstock include ferrous ores and scrap metals.

The electric arc furnace may be any one of a brush-arc furnace, a DC-arc furnace and a submerged-arc furnace.

An open bath or partially open bath brush-arc furnace may be used.

It will be appreciated by the person skilled in the art that a brush-arc electric furnace is an electrical furnace whose electrodes are arcing on top of the furnace contents (that is, a burden which locates in a chamber of the furnace) with a short arc length, typically not longer than 100 mm. Exemplary embodiments of a brush-arc electric furnace are provided in international patent application number PCT/IB2011/052428, South African patent number 2012/04751 and

South African provisional patent application number 2019/07850. The contents of these three documents are incorporated herein by reference.

The brush-arc electric furnace may be operated and controlled as described in any one or more of international patent application number PCT/IB2011/052428, South African patent number 2012/04751 and South African provisional patent application number 2019/07850.

The tyre-char fed to the chamber of the electric arc furnace may be obtained by subjecting scrap or discarded tyres to a pyrolysis reaction. It will be appreciated by the person skilled in the art that pyrolysis refers to a thermal decomposition reaction that takes place in the absence or lack of oxygen.

The scrap or discarded tyres may be comminuted prior to subjecting it to a pyrolysis process.

The scrap or discarded tyres may be comminuted by a process selected from the group consisting of slitting, cutting, shredding, chipping, grinding, crumbling and combinations of these processes.

Steel present in the scrap or discarded tyres may be removed by subjecting the whole or comminuted scrap or discarded tyres to a mechanical, a magnetic or a combination of a mechanical and magnetic process. The steel may be removed from the whole or comminuted scrap or discarded tyres prior to subjecting the tyres to a pyrolysis reaction.

By subjecting the whole or comminuted scrap or discarded tyres to a pyrolysis reaction, three main products are formed. The three main products are: (D a pyrolysis oil (also known as a bio-oil); (i) synthetic gas; and (iii) tyre-char.

Importantly, by subjecting the whole or comminuted scrap or discarded tyres to a pyrolysis reaction, volatiles present in the tyres are removed or at least substantially reduced.

The pyrolysis oil and synthetic gas may be used to heat (for example, by using the pyrolysis oil as a fuel for a burner of a pre-heating furnace) and/or partially reduce metal oxides that form part of the ferroalloy feedstock solids (for example, by causing the synthetic gas to permeate through the ferroalloy feedstock solids) prior to feeding the ferroalloy feedstock solids to the burden that locates in the chamber of the electric arc furnace.

The tyre-char may be fed together with or separately from the ferroalloy feedstock solids to the burden. The rate at which tyre-char is fed to the burden may be controlled.

The ferroalloy smelting process may include the additional step of feeding a fossil fuel source of carbon to the burden. The fossil fuel source of carbon may be used as an additional reductant or as an additional energy source in the electric arc furnace. The fossil fuel source of carbon may be fed to the burden together with or separately from the tyre-char and the ferroalloy feedstock solids.

The ferroalloy smelting process may include the additional step of pre-heating the ferroalloy feedstock solids in a pre-heating furnace prior to it being fed to the burden.

The ferroalloy feedstock solids may also be pre-reduced in a furnace prior to it being fed to the burden. The pre-reduction reaction may be in the solid state.

The tyre-char fed to the burden may also act as a slag foaming agent.

The tyre-char fed to the burden may also act as a combustible energy source in the electric arc furnace.

According to a second aspect of the invention, there is provided for a ferroalloy smelting 5 process including the steps of: — feeding ferroalloy feedstock solids to a melting furnace, the melting furnace being in fluid flow communication with an electric arc furnace; — melting at least a portion of the ferroalloy feedstock solids in the melting furnace to form a molten ferroalloy feedstock; - feeding the molten ferroalloy feedstock to a burden that locates in a chamber of the electric arc furnace, the burden comprising at least a liquid metal product, a liquid slag product, molten ferroalloy feedstock and ferroalloy feedstock solids dispersed therein; — feeding tyre-char that include carbon to the burden; — energizing electrodes of the electric arc furnace to create electric arcs that heat the burden and melt the ferroalloy feedstock solids and tyre-char in the burden; and — reducing ferrous metal oxides that form part of the molten ferroalloy feedstock and ferroalloy feedstock solids to form a liquid metal that reports to the liquid metal product and a liquid slag that reports to the liquid slag product, wherein the carbon of the tyre-char fed to the burden acts as a reducing agent to decrease an oxidation state of the ferrous metal oxides that form part of the molten ferroalloy feedstock and ferroalloy feedstock solids fed to the burden.

According to a third aspect of the invention, there is provided for the use of carbon from tyre- char as a reducing agent in a smelting process that is performed in an electric arc furnace.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING figure 1 is a schematic diagram of a brush-arc electric furnace in which the ferroalloy smelting process according to the first aspect of the invention is performed.

DETAILED DESCRIPTION OF THE INVENTION

With reference to figure 1, a brush-arc electric furnace in which the ferroalloy smelting process according to the first aspect of the invention is performed is indicated by reference numeral 10.

A brush-arc electric furnace is used to describe the invention below, but a person skilled in the art will appreciate that the ferroalloy smelting process of the invention can also be performed in a submerged-arc or DC-arc furnace.

The ferroalloy smelting process according to the first aspect of the invention includes the steps of: — feeding ferroalloy feedstock solids (not shown) to a burden 12 that locates in a chamber 14 of a brush-arc electric furnace 10, the burden 12 comprising at least a liquid metal product 124, a liquid slag product 12b and ferroalloy feedstock solids (not shown) dispersed therein; — feeding tyre-char (not shown) that include carbon to the burden 12; — energizing electrodes 16a and 16b of the brush-arc electric furnace 10 to create electric arcs 18a and 18b that heat the burden 12 and melt the ferroalloy feedstock solids (not shown) and tyre-char (not shown) in the burden 12; and — reducing ferrous metal oxides that form part of the ferroalloy feedstock solids (not shown), to form a liquid metal (not shown) that reports to the liquid metal product 12a and a liquid slag {not shown) that reports to the liquid slag product 12b, wherein the carbon of the tyre-char (not shown) fed to the burden 12 acts as a reducing agent to decrease an oxidation state of the ferrous metal oxides that form part of the ferroalloy feedstock solids {not shown) fed to the burden 12.

The brush-arc electric furnace 10 is typically any one of the brush-arc electric furnaces described in international patent application number PCT/IB2011/052428, South African patent number 2012/04751 and South African provisional patent application number 2019/07850. The contents of these three documents are incorporated herein by reference.

The brush-arc electric furnace 10 is typically operated and controlled as described in any one or more of international patent application number PCT/IB2011/052428, South African patent number 2012/04751 and South African provisional patent application number 2019/07850.

The step of feeding ferroalloy feedstock solids (not shown) to the burden 12 is indicated by process stream (1) in figure 1. The ferroalloy feedstock solids (not shown) may be heated in a pre-heating furnace (not shown) and/or at least partially melted in a melting furnace (not shown) and/or pre-reduced in a furnace (not shown} prior to it being fed to the burden 12. The ferroalloy feedstock solids fed to the burden 12 typically have a diameter of 6 mm or less.

The step of feeding tyre-char (not shown) that includes carbon to the burden 12 is indicated by process stream (II) in figure 1. In the embodiment shown in figure 1, tyre-char (not shown) are fed separately from the ferroalloy feedstock solids (not shown) to the burden 12 of the brush- arc electric furnace 10.

The tyre-char (not shown) fed to the burden 12 are obtained by subjecting scrap or discarded tyres to a pyrolysis reaction. The scrap or discarded tyres (not shown) are comminuted prior to subjecting it to the pyrolysis reaction. Steel present in the scrap or discarded tyres are also removed therefrom prior to subjecting it to a pyrolysis reaction.

With the tyre-char (not shown) and ferroalloy feedstock solids (not shown) dispersed in the burden 12, the electrodes 16a and 16b of the brush-arc electric furnace 10 are energized to create electric arcs 18a and 18b that arc on top of the burden 12. By arcing on top of the burden 12, the electric arcs 18a and 18b heats the burden 12, tyre-char (not shown) fed thereto and ferroalloy feedstock solids (not shown) dispersed therein. In this manner, enough heat is generated to melt the tyre-char (not shown) and the ferroalloy feedstock solids (not shown).

The amount of heat generated by the electric arcs 18a and 18b is controlled to ensure that the burden 12 and its constituent parts are heated to a temperature at which reduction of a selected metal oxide present in the ferroalloy feedstock solids may take place.

By virtue of the heat generated by the arcs 18a and 18b, carbon of the tyre-char binds to an oxygen atom of a metal oxide that forms part of the ferroalloy feedstock solids (not shown) to form a carbon monoxide (CO) off-gas. In this manner an oxidation state of the ferrous metal oxides is decreased. That is, the ferrous metal oxides that form part of the ferroalloy feedstock solids are reduced. During the reduction reaction, a liquid metal (not shown) and a liquid slag (not shown) are formed. The liquid metal (not shown) reports to the liquid metal product 12a and the liquid slag (not shown) reports to the liquid slag product 12b.

The carbon monoxide (CO) off-gas is extracted from the chamber 14 of the brush-arc electric furnace 10. Process stream (111) in figure 1 indicates the step of extracting the carbon monoxide (CO) off-gas from the chamber 14 of the brush-arc electric furnace 10.

The liquid metal product 12a is typically tapped periodically via a tap hole (not shown) in a side wall of the brush-arc electric furnace 10. However, the liquid metal product 12a may also be tapped continually via a tap hole (not shown) in a side wall of the brush-arc electric furnace 10.

The step of tapping the liquid metal product 12a from the chamber 14 of the brush-arc electric furnace 10 is indicated by process stream (IV) in figure 1.

The liquid slag product 12b is also typically tapped periodically via a tap hole (not shown) in a side wall or base of the brush-arc electric furnace 10. However, the liquid slag product 12b may also be tapped continually via a tap hole (not shown) in a side wall or base of the brush- arc electric furnace 10. The step of tapping the liquid slag product 12b from the chamber 14 of the brush-arc electric furnace 10 is indicated by process stream (V) in figure 1.

Mass and energy balances exemplifying the advantages of the present invention

Below follows a comparison between two smelting processes: (i) a first conventional smelting process that utilizes anthracite as a source of reducing agents; and (ii) a second smelting process that utilizes the process of the first aspect of the invention.

It is to be noted that the characteristics and parameters of the brush-arc electric furnaces used in both processes are the same.

First conventional smelting process that utilizes anthracite as a source of reducing agents:

Ferroalloy feedstock solids are fed to a chamber of an electric brush-arc furnace at rate of 21.11 metric tons per hour and at a temperature of 25°C. The ferroalloy feedstock solids comprise, by weight percentage, approximately: — 43.38% Cr2O3; — 27.2% FeO; — 15.51% Al2O3; — 11.33% MgO; — 2.32% SiOz; — 0.18% CaO; and — 0.08% CaCO:.

Anthracite is also fed as a reductant to the chamber of the electric brush-arc furnace. Anthracite is fed to the chamber of the electric brush-arc furnace at a rate of 5.55 metric tons per hour and at a temperature of 25°C. The anthracite fed to the chamber of the electric brush-arc furnace comprise, by weight percentage, approximately: — 77.8% C; — 7.2% SiO; — 4.72% Al2O3;

— 0.4% CaO; — 0.3% MgO; — 0.8% Fe:0:; — 0.4% MnO; — 1.38% S; and — 7% CHa.

Quartz is also fed to the chamber of the brush-arc electric furnace at a rate of 0.7 metric tons per hour and at a temperature of 25°C.

Moisture is fed to the chamber of the brush-arc electric furnace at a rate of 0.27 metric tons per hour and at a temperature of 25°C.

Air is introduced to the chamber of the brush-arc electric furnace at a rate of 0.15 metric tons per hour and at a temperature of 25°C. 40,000.00 kW of electrical energy is provided to the electrodes of the brush-arc electric furnace to smelt the ferroalloy feedstock solids fed to chamber of the brush-arc electric furnace. The brush-arc electric furnace loses 10,000 kW of electrical energy due to heat losses.

The smelting reaction results in the formation of liquid metal product, a liquid slag product, dust and an off-gas.

The liquid metal product is tapped from the brush-arc electric furnace at a rate of 10.53 metric tons per hour and a temperature of 1,650°C. The liquid metal product that is tapped from the brush-arc electric furnace comprise, by weigh percentage, approximately: — 51.25% Cr; — 39.86% Fe; — 0.3% Si; — 8.5% C; and - 0.09% S.

The liquid slag product is tapped from the brush-arc electric furnace at a rate of 9.46 metric tons per hour and at a temperature of 1,750°C. The liquid slag product tapped from the brush- arc electric furnace comprise, by weight percentage, approximately 12.46% Cr:O:3.

Thus, 87% of the Cr and 95% of the Fe fed to the brush-arc electric furnace are reports to the liquid metal product.

Dust is removed from the brush-arc electric furnace at a rate of 0.23 metric tons per hour and at a temperature of 900°C.

A total volume of 6,676 m? per hour of the off-gas formed during the smelting reaction is extracted from the brush-arc electric furnace. The off-gas is extracted from the brush-arc electric furnace at a rate of 7.58 metric tons per hour and at a temperature of 900°C. The off- gas extracted from the brush-arc electric furnace comprise, by weight percentage, approximately: — 92.22% CO; - 0.4% Hz; — 1.58% Na; and — 5.13% CHa

The power consumption of the brush-arc electric furnace, with the above-described reagents, is 3.8 megawatts hour per metric ton of liquid metal product produced. Annually, 73,064 metric tons of liquid metal product may be produced in this manner.

Second smelting process that utilizes the process of the first aspect of the invention:

Ferroalloy feedstock solids are fed to a chamber of an electric brush-arc furnace at rate of 21.36 metric tons per hour and at a temperature of 25°C. The ferroalloy feedstock solids comprise, by weight percentage, approximately: — 43.38% CrzO3; — 27.2% FeO; — 15.51% Al:O:3; — 11.33% MgO; — 2.32% SiOz; — 0.18% CaO; and — 0.08% CaCO:.

Tyre-char is fed as a reductant to the chamber of the brush-arc electric furnace. Tyre-char is fed to the chamber of the brush-arc electric furnace at a rate of 5.34 metric tons per hour and at a temperature of 25°C. The tyre-char fed to the chamber of the brush-arc electric furnace comprises, by weight percentage, approximately: — 82.91% C; - 10.5% SiO; — 2.21% CaO; — 3.39%Fe20:; and

- 1% S.

Quartz is also fed to the chamber of the brush-arc electric furnace at a rate of 0.6 metric tons per hour and at a temperature of 25°C.

The liquid metal product is tapped from the brush-arc electric furnace at a rate of 10.79 metric tons per hour and a temperature of 1,650°C. The liquid metal product that is tapped from the brush-arc electric furnace comprise, by weigh percentage, approximately: - 50.62% Cr; - 40.52% Fe; - 0.3% Si; — 8.5% C; and - 0.06% S.

The liquid slag product is tapped from the brush-arc electric furnace at a rate of 9.36 metric tons per hour and at a temperature of 1,750°C. The liquid slag product tapped from the brush- arc electric furnace comprise, by weight percentage, approximately 12.74% Cr2O:.

A total volume of 6,254 m? per hour of the off-gas formed during the smelting reaction is extracted from the brush-arc electric furnace. The off-gas is extracted from the brush-arc electric furnace at a rate of 7.34 metric tons per hour and at a temperature of 900°C. The off- gas extracted from the brush-arc electric furnace comprise, by weight percentage, approximately: — 97.52% CO; — 0.42% Hz; — 1.58% Na.

The power consumption of the brush-arc electric furnace, with the above-described reagents, is 3.71 megawatts hour per metric ton of liquid metal product produced. Annually, 74,836 metric tons of liquid metal product may be produced in this manner.

It will be appreciated by a person skilled in the art that a comparison between the two above- described smelting process exemplifies the efficiencies and advantages of using tyre-char as a reductant, as opposed to anthracite, in a ferroalloy smelting process.

It will be appreciated by those skilled in the art that the invention is not limited to the precise details as described herein and that many variations are possible without departing from the scope of the invention. As stated, the electric arc furnace may be any one of a brush-arc furnace, a DC-arc furnace or a submerged-arc furnace. As such, the present invention extends to all functionally equivalent processes, methods and uses that are within its scope.

The description is presented by way of example only in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show more detail than is necessary for a fundamental understanding of the invention. The words which have been used herein are words of description and illustration, rather than words of limitation.

Claims

CONCLUSIONS

A process for smelting iron alloys comprising the steps of: — feeding solid ferroalloy raw material to a charge contained in a chamber of an electric arc furnace, the charge containing at least one liquid metal product, one liquid slag product and dispersed solid ferroalloy raw material; — feeding tire carbon with carbon to the cargo; — energizing electrodes of the arc furnace to create electric arcs which heat the charge and melt the iron alloy solids and tire carbon in the charge; and — Reducing ferrous metal oxides that are part of the solid ferroalloy feedstock to form a liquid metal that contributes to the liquid metal product and a liquid slag that contributes to the liquid slag product, where the carbon from the tire coal fed into the cargo , acts as a reducing agent to reduce an oxidation state of the ferrous metal oxides that are part of the solid ferroalloy raw material supplied to the cargo.

The iron alloy smelting method according to claim 1, characterized in that the electric arc furnace is one of a brush arc furnace, a direct current arc furnace and a submerged electric arc furnace.

A method of smelting iron alloys according to claim 1 or claim 2, characterized in that the strip coal fed to the chamber of the electric arc furnace is obtained by subjecting scrap or scrap tires to a pyrolysis reaction.

The method of smelting iron alloys according to claim 3, characterized in that the scrapped or discarded tires are comminuted before being subjected to the pyrolysis process.

A method of smelting iron alloys according to claim 3 or claim 4, characterized in that the steel contained in the scrap or scrap tires is removed therefrom before the scrapped or scrap tires are subjected to the pyrolysis reaction.

The method of smelting iron alloys according to any of the preceding claims, wherein the method of smelting an iron alloy includes the additional step of supplying a fossil fuel source of carbon to the charge.

The method of smelting iron alloys according to claim 6, wherein the fossil fuel source of carbon is used as an additional reducing agent in the method of smelting iron alloys.

The iron alloy smelting process according to claim 6 or 7, wherein the fossil fuel source of carbon is used as an additional source of energy in the iron alloy smelting process.

A method of smelting iron alloys according to any one of the preceding claims, wherein the method of smelting iron alloys includes the additional step of preheating the ferroalloy raw material in a preheating furnace before feeding it to the charge.

A method of smelting ferro-alloys according to any one of the preceding claims, wherein the method of smelting iron-alloys includes the additional step of pre-reducing the solid ferro-alloy raw material before feeding it to the charge.

A method of smelting iron alloys according to any one of the preceding claims, wherein the strip coal supplied to the charge also acts as a slag blowing agent in the charge.

A method of smelting iron alloys according to any one of the preceding claims, wherein the strip coal fed to the charge also functions as a combustible source of energy in the electric arc furnace.

A method of smelting iron alloys comprising the steps of: feeding iron alloy solids to a melting furnace, the melting furnace being in fluid flow communication with an electric arc furnace; — melting at least part of the solid ferroalloy raw material in the melting furnace to form a molten ferroalloy raw material; feeding the molten ferroalloy raw material to a charge contained in a chamber of the electric arc furnace, the charge comprising at least a liquid metal product, a liquid slag product, molten ferroalloy raw material and solid ferroalloy raw material dispersed therein; — adding carbon tires to the cargo; — energizing electrodes of the electric arc furnace to create electric arcs that heat the load and melt the solid ferroalloy raw material and tire carbon in the load; and — Reducing ferrous metal oxides contained in the molten ferroalloy raw material and the solid ferroalloy raw material to form a liquid metal that contributes to the liquid metal product and a liquid slag that contributes to the liquid slag product, the carbon of the bonds of carbon being added to the cargo acts as a reducing agent to reduce an oxidation state of the ferrous metal oxides included in the molten ferroalloy raw material and the solid ferroalloy raw material added to the cargo.

14. Use of tire carbon as a reducing agent in a smelting process carried out in an electric arc furnace.