DESC:*** Complete Specification ***

“Fluxing mineralizer cum binder and method employing the same to facilitate smelting of ferro alloys”

Cross references to related applications: This complete specification is filed further to patent application No. 202331051449 filed on 31/07/2024 with provisional specification titled “Fluxing mineralizer cum binder and method employing the same to facilitate smelting of ferro alloys”. The entire contents of this provisional specification are incorporated herein, in its entirety, by way of reference.

Field of the invention
This invention relates to processes for treatment of metal oxide ores to obtain their metallic constituents. More specifically, the disclosures hereunder outline an inventive fluxing mineralizer cum binder composition and its use to facilitate smelting in conventional smelting of ferro alloys.

Definitions: Before undertaking the detailed description of the invention below, it may be advantageous to set forth definitions of certain words or phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect, with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and certain definitions are set forth for this document, as follows-
(a) “SAF” refers to Submerged Arc Furnace.
(b) “EAF” refers to Electric Arc Furnace.
(c) “Reductant” refers to a substance capable of bringing about the reduction of another substance as it itself is oxidized.
(d) “Ferro alloys” refers to alloys of iron with a high proportion of one or more other elements, such as manganese, silicon, chromium, or molybdenum and the like.
(e) “Mineralizer” refers to a substance or agent used in various industrial processes, particularly in the production of ceramics and materials, to facilitate and control the formation of desired mineral phases. Fluxes, nucleating agents, and phase stabilizers are some types of mineralizers commonly used in the industry.
(f) “Carbonaceous Materials” refer to substances primarily composed of carbon, such as Graphite, Activated Carbon, Coal, Charcoal, Graphene and so on.
(g) “Oxidized Ores” refers to chromite ore (for ferrochromium), manganese ore (for ferromanganese), or others depending on the alloy being produced.

Background of the invention
The smelting of ferroalloys involves a process where raw materials containing iron and other elements are melted together in an electric arc furnace or a submerged arc furnace at high temperatures. This process is crucial for producing ferroalloys, which are used as additives in steelmaking and other alloy production processes.

As conventionally known, the raw materials used in the smelting of ferroalloys typically include one or more each among:
(a) Oxidized Ores.
(b) Carbon source in the form of coke, coal, or Carbonaceous Materials, which provide the reducing agent to extract metals from the ores.
(c) Agents including materials like limestone or dolomite, which help in slag formation and assist in the separation of impurities.

For sake of pertinent background, it shall be worthwhile to summarily note the stages involved in conventional smelting operations-
(a) Preparation of raw materials - Raw materials are carefully weighed and mixed to achieve the desired alloy composition.
(b) Charging - mixed raw materials are charged into the smelting furnace (EAF or SAF).
(c) Melting and reduction - Once in the furnace, the materials are heated to very high temperatures (often exceeding 2000°C in EAFs and 1600-1800°C in SAFs), causing them to melt. The carbon in the coke or coal acts as a reducing agent, reacting with the oxygen in the ores to extract the metal components (like chromium, manganese, silicon, etc.).
(d) Formation of desired alloy - As the reduction process proceeds, the molten metal collects in the bottom of the furnace. Alloying elements like chromium, manganese, silicon, etc., combine with the molten iron to form the desired ferroalloy.
(e) Slag formation - The fluxes added earlier react with impurities and gangue materials present in the ore to form a slag. This slag floats on top of the molten metal and is periodically removed from the furnace.
(f) Tapping out of final product - Once the smelting process is complete and the desired alloy composition is achieved, the molten ferroalloy is tapped from the furnace and cast into molds (typically in ingot or granular form) for further processing and use.
(g) Downstream processing - After smelting, ferroalloys may undergo additional processes such as crushing, screening, and sometimes refining to remove impurities and adjust the final alloy composition to meet specific application(s).

Ferroalloys produced through smelting are primarily used in steelmaking as alloying elements to impart specific properties such as corrosion resistance, hardness, and strength to steel. They also find applications in other industries where these properties are desired, such as in the production of stainless steel, tool steel, and specialty alloys used in automotive, construction, and aerospace industries.

Hence, there is a global utility of these processes and therefore continuing demand for improvements therein to make them economically viable as well as environmentally safe for large scale implementation all over the world. Researchers worldwide are working on various nodes to seek improvements in smelting of ferroalloys. The applicant herein has focused on the identification, synthesis and utilization of agents to facilitate smelting in conventional smelting of ferro alloys.

The applicant herein identifies the lack of optimum agents to facilitate and control the formation of desired mineral phases, and therefore improve precision / accuracy and thus purity of the end product, being largely unaddressed in the art, and therefore target of focused research underlying the present invention.

The applicant herein identifies, among others, Chromium (Cr) to be a vital industrial element being applicable in various conventional smelting processes. Chrome, specifically in the form of chromium-containing ores like Chromite (Cr2O3), plays a crucial role in the smelting process, particularly in the production of ferrochrome.

Metallic chromium is obtained from smelting of Chromite, an oxide mineral belonging to the spinel group which is found in mafic-ultramafic igneous intrusions and are also sometimes found in metamorphic rocks. Among other naturally-occurring variants, Ferrochrome (FeCr2O4) is the most commonly occurring form of Chromite being used in the industry for the aforementioned applications.

An issue herein is that the smelting of Oxidized Ores (such as Cr / Mn – based ores or other oxidized ores as defined in the foregoing narrative) using traditional carbothermic methodologies is that it is extremely energy-intensive due to high temperatures mandatory for occurrence of reduction and metallization. Therefore, there is a pressing need for some means that can reduce the energy demand in such processes.

One promising approach in this line is prior reduction, that is, direct reduction of the Oxidized Ore before smelting. This allows reduction and metallization to occur at lower temperatures, hence reducing the energy demand in the process.

An issue herein is that prior reduction of Oxidized Ores, specially chromite, follows a solid-state chemistry approach, that is, both the Oxidized Ore and the Reductant are in solid state, which makes their reactivity slow and inefficient in throughput of achieving completely reduced chromite ore. Thus, a way of avoiding an entirely solid-state chemistry approach shall be evidently advantageous, and is thus wanting in the art.

Also, during the smelting of Oxidized Ore in electric arc furnaces or submerged arc furnaces, fluxes like limestone or dolomite are added to react with impurities and gangue materials. This process helps in forming a slag layer on top of the molten metal. Among Oxidized Ores, Chromite itself can contribute to the formation of slag because it contains silica (SiO2) and alumina (Al2O3) along with chromium oxide (Cr2O3). These components can react with fluxes and other oxides present in the furnace to form complex silicates and aluminates, which constitute the slag. The issue here is that Chromite-containing slag can have a higher melting point compared to typical ferrous slag due to the presence of refractory oxides like Cr2O3, and that the presence of chromium in the slag affects its chemical composition. Chromium compounds in slag can influence its behavior, including its viscosity, fluidity, and potential environmental impacts if not properly managed. Chromium in slag can pose environmental challenges if it leaches into the surrounding environment, particularly in water bodies. Therefore, proper handling and disposal methods are essential to mitigate these risks.

Furthermore, chromite in slag during the smelting of chromium-containing alloys is a significant consideration due to its impact on slag composition, properties, and environmental implications. Proper management and processing of chromite-containing slag are essential to optimize recovery of valuable metals and mitigate environmental risks associated with chromium compounds.

Cumulatively, the art therefore requires a high-quality reductant for prior reduction of chromite ore, which is typified in being cost-effective and being commonly available / easy to source for the industry, besides being applicable for non-chromite ores for production of ferroalloys.

Prior art, to the extent surveyed, lists some scattered attempts to address the issues mentioned hereinabove. For example, CN107190139A (2017, Assigned to Jiangsu Province Metallurgical Design Institute Co Ltd) teaches a method of Ni and Cr contained ferroalloy smelting, wherein lateritic nickel ore is used as a native nickel material, and admixed with chromite powder, reducing agent, binding agent, fluxing agent and charged to a rotary hearth furnace for undergoing a high temperature reduction, to result in metallized pellets which are then charged to an EAF to obtain nickeliferous ferrochrome.

Another example, CN108385009A (2018, Assigned to Yancheng Xinyang Electric Heat Material Co Ltd) teaches a method to prepare a ferrochrome molybdenum alloy. Here, molybdenum ore of sulfur-bearing, cobalt is subjected to levigate processing and then uniformly mixed with chromite powder, reinforcing agent, and water and charged to a rotary hearth furnace for undergoing a high temperature reduction, to result in metallized pellets which are then charged to an EAF to obtain ferrochrome molybdenum alloy.

As the reader can thus appreciate, the prior art, to the extent surveyed, does not list a single effective solution embracing all considerations mentioned hereinabove, thus preserving an acute necessity-to-invent for the present inventor/s who, as result of focused research, has come up with novel solutions for resolving all needs once and for all. Work of the applicant/s hereof, specifically directed against the technical problems recited hereinabove and currently part of the public domain including earlier filed patent applications, is neither expressly nor impliedly admitted as prior art against the present disclosures.
Objectives of the present invention
The present invention is identified in addressing at least all major deficiencies of art discussed in the foregoing section by effectively addressing the objectives stated under, of which:

It is a primary objective to establish a high-quality non-solid-state, fluxing, mineralizer cum binder composition, particularly not identifying entirely with solid state chemistry, for use in facilitating smelting in conventional smelting of ferro alloys.

It is another objective further to the aforesaid objective(s) to use said high-quality fluxing mineralizer cum binder composition for the establishment of a method for efficient production of ferro alloys.

It is another objective further to the aforesaid objective(s) whereby the use of said fluxing mineralizer cum binder composition improves the efficiency in reduction process of Oxidized Ores.

It is another objective further to the aforesaid objective(s) whereby the use of said fluxing mineralizer cum binder composition results in lowering of the energy consumption in conventional process of smelting in SAF.

It is another objective further to the aforesaid objective(s) whereby the use of said fluxing mineralizer cum binder composition results in lowering of the reductant consumption in conventional process of smelting in SAF.

It is another objective further to the aforesaid objective(s) whereby the use of said fluxing mineralizer cum binder composition results in reduction of the energy demand conventionally inevitable for occurrence of reduction and metallization.

It is another objective further to the aforesaid objective(s) whereby the use of said fluxing mineralizer cum binder composition results in reduction of smelting time in production of ferro alloys.

It is another objective further to the aforesaid objective(s) whereby the use of said fluxing mineralizer cum binder composition results in reduction of chromite in slag output observed in production of ferro alloys.
The manner in which the above objectives are achieved, together with other objects and advantages which will become subsequently apparent, reside in the detailed description set forth below in reference to the accompanying drawings and furthermore specifically outlined in the independent claims. Other advantageous embodiments of the invention are specified in the dependent claims.

Brief description of drawings
The present invention is explained herein under with reference to the following drawings, in which:

FIGURE 1 is a graph showcasing the reduction of melting point of manganese ore by use of the mineralizer composition of the present invention.

FIGURE 2 is a graph showcasing the reduction of melting point of chromite ore by use of the mineralizer composition of the present invention.

FIGURE 3 is a graph showcasing the reduction of melting point of chromite slag by use of the mineralizer composition of the present invention.

FIGURE 4 is a graph showcasing the reduction of melting point of quartz sand by use of the mineralizer composition of the present invention.

FIGURE 5 is a graph showcasing the reduction of melting point of clinker raw mix
by use of the mineralizer composition of the present invention.

Attention of the reader is now requested to the detailed description to follow which narrates a preferred embodiment of the present invention and such other ways in which principles of the invention may be employed without parting from the essence of the invention claimed herein.

Statement / Summary of the invention
This invention discloses an inventive fluxing mineralizer cum binder composition and its use in reduction process of Oxidized Ores to thus facilitate smelting in conventional smelting of ferro alloys with marked reduction in consumptions of energy and reductant, with effective reduction of smelting time and chromite present in the resulting slag.

Detailed Description
Principally, general purpose of the present invention is to assess disabilities and shortcomings inherent to known systems comprising state of the art and develop new systems incorporating all available advantages of known art and none of its disadvantages. Accordingly, the disclosures herein are directed towards an inventive fluxing mineralizer cum binder composition and its use to facilitate smelting in conventional smelting of ferro alloys.

To relate, this invention relates to the reduction process of Oxidized Ore which involves the removal of oxygen from Oxidized Ore by reducing directly by carbonaceous materials or by CO gas, which is generated by the Boudouard reaction.

A yet-preferred embodiment of the present invention disclosed herein relates to a composition and method using said composition whereby the efficiency in reduction process of chromite is enhanced along with lowering of the energy and reductant consumption in conventional process of smelting in SAF. Introduction of a reductant is thus proposed for bringing about prior reduction of Oxidized Ore before smelting.

The temperature of the furnace is to be kept minimum at melting point of metal or slag; whichever is higher. Reduction in temperature of the slag also helps reducing the temperature of the furnace where reduction is carried out.

Accordingly, an inventive method is proposed herein for reducing Oxidized Ore in slag in the non-solid state by adding a composite flux additive. The reduction process is intended to be carried out in SAF. Composition of the flux additive / non-solid-state, fluxing, mineralizer cum binder composition subject of this invention, is showcased in Table 1 below.

Constituent Chemical formula / Makeup Role Content (%) % in raw mix Use % of elements
1) Cryolite, Aluminium Fluoride, Fluorspar Na3AlF6, CaF2, AlF3 Flux; Encourage metallization at lower temperatures; Lowers melting point of oxides 20 to 40 5 to 15 2.5 to 5
2) Hydrated lime and / or Hydrated dolomite Ca(OH)2
And / or
Ca(OH)2,MgO Hydrated lime is a binder and carrier; Hydrated dolomite adds Basicity 20 to 40 2 to 4 (Hydrated lime) and / or 3 to 5 (Hydrated dolomite)
3) Mill scale FeO Breaks the spinel bond and lowers phosphorous pick up 0 to 15 0 to 1.5
4) Carbonaceous material --- Seeding the reduction from core to crust 5% to 15% 0 to 3

Table 1

Reduction happens when the pyro-plastic temperature of oxides or metal is reached, whichever is higher. Normally, oxides have higher melting points. The mineralizer proposed herein aims at lowering the melting point of oxides and also accelerating reduction by way of breaking spinels and starting the reaction from core to crust of the agglomerate.

Rate of reduction increases at pyro-plastic stage. The pyro-plastic stage of oxides requires high temperature and so we need high temperatures for smelting. If we reduce the temperature of pyro plasticity by some flux; we lower the energy consumption. Bath containing cryolite and fluorides reduce the melting point of the oxides to be smelted. Silicon in chromite is also reduced due to high temperature, therein establishing low-silicon chrome, a premium for smelting operations subject hereof.

The flux can be added with carbon, binder or as it is for the intended results. The ore can be grounded and mixed with flux and briquetted for improved results or palletized for best results. Briquetting gives homogeneity whereas pallets give homogeneity and permeability also for better reduction.
Flux proposed herein works in all the cases as above. The efficiency of flux increases in the following order-
(a) As it is as graded lumps along with ore (lumpy or briquetted or pellets)
(b) With Carbon (Anode & Cathode or coke briquettes containing flux) : Reason is better dispersion in SAF.
(c) In briquettes with flux: Reason is homogeneity with oxides.
(d) In pellets with flux: Reason is homogeneity plus permeability for better reductant oxide reaction surface area.

Impact of flux, in the instant application, can be appreciated as under-
a) Average impact ? Ore + Coke + Flux (Na3AlF6)
b) Good impact ? Ore + Coke + Carbon (Anode / Cathode) or coke briquettes containing flux
c) Best impact ? Ore + Binder + Flux in briquettes / pellets

Experimental validation
Via independent scientific experimentation undertaken by the applicant hereof, the non-solid-state, fluxing, mineralizer cum binder composition of this invention has been validated to effectively reduce the melting point of oxides, viz. Fe2O3, MnO2, Cr2O3, and SiO2.

An itemized account of these trials is presented below for reference.
(a) Manganese ore (-150 mesh)
Manganese ore sample (melting temperature = 1290°C) was tested with different percentages of mineralizer composition / flux additive composition of the present invention. Upon adding the flux additive composition of the present invention, the melting point of manganese ore was observed to drop very smoothly. Temperature dropped averaged 30°C in each step. From the Table 2 below and corresponding graph shown in FIGURE 1, it was concluded that working with manganese ore, addition of said flux additive should be 0.5% in a safe and effective and also on practically feasible basis.

Flux additive composition of the present invention (% w/w to Manganese ore sample) Melting Temperature of ore (oC)
0 1290
0.05 1230
0.10 1200
0.30 1170
0.40 1140
0.50 1100
1.00 1050
1.50 1000
2.00 930
2.50 850

Table 2

(b) Chromite ore (-150 mesh)
Chromite ore sample (melting temperature = 1740°C) was tested with different percentages of mineralizer composition / flux additive composition of the present invention. Upon adding the flux additive composition of the present invention, the melting point of Chromite ore was observed to drop very smoothly. Temperature dropped averaged 50°C in each step, as reflected in the data presented in Table 3 below and corresponding graph shown in FIGURE 2.

Flux additive composition of the present invention (% w/w to Chromite ore sample) Melting Temperature of ore (oC)
0% 1740
0.50% 1600
1.00% 1550
1.50% 1490
2.00% 1440
2.50% 1380

Table 3
(c) Chromite slag (-150 mesh)
Chromite slag sample (melting temperature = 1500°C) was tested with different percentages of the mineralizer composition / flux additive composition of the present invention. Upon adding the flux additive composition of the present invention, the melting point of Chromite slag was observed to drop very smoothly. Temperature dropped averaged 30°C in each step, as reflected in the data presented in Table 4 below and corresponding graph shown in FIGURE 3.

Flux additive composition of the present invention (% w/w to Chromite slag sample) Melting Temperature (oC)
0.0% 1500
0.5% 1470
1.0% 1440
1.5% 1400
2.0% 1340

Table 4

(d) Quartz sand (-150 mesh)
Quartz sand sample (melting temperature = 1730°C) was tested with different percentages of the mineralizer composition / flux additive composition of the present invention. Upon adding the flux additive composition of the present invention, the melting point of Quartz sand was observed to drop very smoothly. Temperature dropped averaged 50°C in each step, as reflected in the data presented in Table 5 below and corresponding graph shown in FIGURE 4.

Flux additive composition of the present invention (% w/w to Chromite slag sample) Melting Temperature (oC)
0.0 1730
0.5 1650
1.0 1580
1.5 1470
2.0 1410
2.5 1400
3.0 1390
4.0 1340
5.0 1280

Table 5
(e) Clinker raw mix
Clinker raw mix sample (melting temperature = 1560°C) was tested with different percentages of the mineralizer composition / flux additive composition of the present invention. Upon adding the flux additive composition of the present invention, the melting point of Clinker raw mix was observed to drop very smoothly. Temperature dropped averaged 45°C in each step, as reflected in the data presented in Table 6 below and corresponding graph shown in FIGURE 5.

Flux additive composition of the present invention (% w/w to Quartz sand sample) Melting Temperature (oC)
0.0 1560
0.5 1490
1.0 1440
1.5 1410
2.0 1380

Table 5

Industrial Utility
From the foregoing elaboration, an able method of prior reduction, of Oxidized Ores is thus propounded by the present invention, which is further typified in having-
a) Reduction in non-solid state
b) Reduction without requiring high percentage of cryolite
c) Reduction in energy consumption
d) Reduction in cost.
e) Reduction of smelting time
f) Reduction of Chromite in Slag.

Significance of this invention can be appreciated from that the non-solid-state, fluxing, mineralizer cum binder composition propounded herein and the method of prior reduction, of Oxidized Ores by use of said non-solid-state, fluxing, mineralizer cum binder composition score above conventional smelting operations, by-
a) At least 5% reduction in consumption of energy;
b) At least 5% reduction in consumption of reductant;
c) At least 5% reduction in reduction of smelting time;
d) At least 20% reduction in chromite present in slag; and
e) At least 40% reduction in silicon content (for chromite).

As will be realized further, the present invention is capable of various other embodiments and that its several components and related details are capable of various alterations, all without departing from the basic concept of the present invention.

Accordingly, the foregoing description will be regarded as illustrative in nature and not as restrictive in any form whatsoever. Modifications and variations of the system and apparatus described herein will be obvious to those skilled in the art. Such modifications and variations are intended to come within ambit of the present invention, which is limited only by the appended claims. ,CLAIMS:1) A non-solid-state, fluxing, mineralizer cum binder composition for prior reduction of an oxidized ore to thereby improve the energy and reductant consumption during smelting of ferro alloys, said composition comprising-

(a) 20% to 40% w/w of a flux to encourage metallization at lower temperatures and lower the melting point of oxides;

(b) 20% to 40% w/w of a binder and carrier, being typified in introduction of added basicity;

(c) 0% to 15% w/w of an agent capable of breaking spinel bonds and reducing phosphorous pick up; and

(d) 5% to 15% w/w Carbonaceous material for seeding the reduction from core to crust.

2) The non-solid-state, fluxing, mineralizer cum binder composition for prior reduction of an oxidized ore to thereby improve the energy and reductant consumption during smelting of ferro alloys as claimed in claim 1, wherein the flux is selected at least one among Cryolite, Aluminium Fluoride, and Fluorspar.

3) The non-solid-state, fluxing, mineralizer cum binder composition for prior reduction of an oxidized ore to thereby improve the energy and reductant consumption during smelting of ferro alloys as claimed in claim 1, wherein the binder and carrier is selected at least one between hydrated lime and hydrated dolomite.

4) The non-solid-state, fluxing, mineralizer cum binder composition for prior reduction of an oxidized ore to thereby improve the energy and reductant consumption during smelting of ferro alloys as claimed in claim 1, wherein he agent capable of breaking spinel bonds and reducing phosphorous pick up is Mill scales.

5) The non-solid-state, fluxing, mineralizer cum binder composition for prior reduction of an oxidized ore to thereby improve the energy and reductant consumption during smelting of ferro alloys as claimed in claim 1, wherein the Carbonaceous material is selected at least one among Graphite, Activated Carbon, Coal, Charcoal, Graphene, their equivalents and their combinations.

6) An improved process for smelting of ferro alloys by introduction of the non-solid-state, fluxing, mineralizer cum binder composition claimed in any one of the preceding claims, said process scoring above conventional smelting operations, by-

(a) At least 5% reduction in consumption of energy;

(b) At least 5% reduction in consumption of reductant;

(c) At least 5% reduction in reduction of smelting time;

(d) At least 20% reduction in chromite present in slag; and

(e) At least 40% reduction in silicon content.

7) The improved process for smelting of ferro alloys by introduction of the non-solid-state, fluxing, mineralizer cum binder composition claimed in claim 6, wherein said non-solid-state, fluxing, mineralizer cum binder composition is introduced to the ore in a form selected among-

(a) Graded lumps, being in either among lumpy, briquetted, and pelletized form;

(b) With Carbon, Anode and Cathode in particular; and

(c) As part of coke briquettes containing said flux.

8) A non-solid-state, fluxing, mineralizer cum binder composition for prior reduction of an oxidized ore to thereby improve the energy and reductant consumption during smelting of ferro alloys as substantively claimed in any one of the preceding claims and as substantively disclosed in the accompanying description and drawings.

9) An improved process for smelting of ferro alloys by incorporation of the non-solid-state, fluxing, mineralizer cum binder composition claimed in any one of the preceding claims and as substantively disclosed in the accompanying description and drawings.