TECHNICAL FIELD
The present disclosure relates to the field of metallurgy. Particularly, the present disclosure
relates to a process for production of 200 series stainless steel scrap by using low grade raw
materials - chromite ore tailings and sub-grade manganese ore.
BACKGROUND OF THE DISCLOSURE
Chromium has diverse applications and is widely used in the refractory, chemical,
metallurgical, and casting industries. Chromite ore is the only source of producing chromium.
Of all the chromium produced, almost 90% is being used in the metallurgical field. Like most
heavy metals, chromite ores are treated by gravity separation method for its upgradation, which
in turn produces large number of fine-sized tailings (<25 µm) having higher silica content.
These chromite ore tailings pose a huge environmental hazard and have a considerable amount
of metallic content that goes untapped in most of the ferrochrome production plants. Currently,
these tailings generated in ferrochrome plants are dumped in dump yards which raises a
concern of space and environmental hazards.
Manganese (Mn) is an important alloying element for stainless steel as it decreases the
brittleness and increases the strength. Like chromite ore tailings, sub-grade Mn ores generated
during the mining of Mn ores remain un-utilized because of low metallic value of the ores.
Chromite ore tailings and sub-grade Mn ores both have important alloying elements for making
stainless-steel (Cr, Mn and Ni). The present disclosure explores the possibility of using these
ores in the stainless-steel production.
There have been a few reports in the art on utilizing a low-grade chrome ore or tailings or
chromite ore processing residue. U.S. Pre-grant Publication No. 2004/0086438A1 discloses
simultaneous recovery of chromium and iron from chromite ore processing residue (COPR) as
a chromate salt and iron salt. The process involves treating COPR with metal hydroxide
followed by leaching in the temperature range of 30-100˚C and other hydrometallurgical
routes. This invention recovers chromium and iron as salts not as metal, which has very limited
use.
CN101380510A discloses utilization of chromium slag via leaching route by converting
hexavalent chromium to tri-valent chromium. After detoxifying chromium slag, the process
disclosed in this publication provides products such as chromium, magnesium and aluminum

hydroxides, silicon dioxide, magnetic tri-iron tetroxide, calcium sulfate dihydrate, corundum
intermediate, sodium chloride, and chromite ore tailings. This publication does not disclose
recovery of metal from chromite ore tailings.
CN108580021B and CN108246491A disclose recovering chromium concentrate from tailings
of high carbon ferrochrome dry and wet slag, respectively. Indian patent publications,
IN20110068112, IN20140031612, IN201631008680A and IN201731008862 disclose the
beneficiation of chromite tailings mainly for the enrichment purpose.
CN105671413A discloses an electro-silicothermic process, where an ore is smelted to obtain a
silicon-chromium alloy as low carbon intermediate alloy and manganese ore as a refining
agent.
However, none of the previous studies explore the possibility of using low-grade chromite ore
tailings and sub-grade manganese ore in a single smelting process to produce 200 series
stainless steel scrap. The present disclosure utilizes otherwise discarded low-grade chromium
and manganese ores to produce valuable steel scrap and addresses the problem of waste
disposal and environmental hazards of these ores.
STATEMENT OF THE DISCLOSURE
The present disclosure relates to a method for preparing 200 series stainless steel scrap, said
method comprising: a) pelletizing a first mixture comprising chromite tailings, a reducing
agent, a fluxing agent, and a binder to obtain a chromite-tailings pellet; b) pelletizing a second
mixture comprising a noble metal oxide and a binder to obtain noble metal oxide pellets; c)
pelletizing a third mixture comprising low-grade manganese ore, a reducing agent, a fluxing
agent, and a binder to obtain a low-grade manganese ore pellet; d) adding the chromite-tailings
pellet to an arc furnace at a temperature of about 1500-1600˚C and allowing the chromite-
tailings pellet to melt to obtain a first molten mass; e) adding the noble metal oxide pellets into
the first molten mass and allowing the noble metal oxide pellets to melt to obtain a second
molten mass; f) adding the low-grade manganese ore pellet to the second molten mass and
allowing the low-grade manganese ore pellet to melt to obtain a third molten mass; and g)
cooling the third molten mass to obtain 200 series stainless steel scrap..

The present disclosure also relates to the 200 series stainless steel scrap obtained by the
methods described herein.
The present disclosure also relates to use of chromite ore tailings and use of low-grade
manganese ore to produce 200-series stainless steel scrap.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1 shows a schematic of an exemplary process for producing 200 series stainless steel
scrap according to the present disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
With respect to the use of any plural and/or singular terms herein, those having skill in the art
can translate from the plural to the singular and/or from the singular to the plural as is
appropriate to the context and/or application. The various singular/plural permutations may be
expressly set forth herein for sake of clarity. The use of the expression “at least” or “at least
one” suggests the use of one or more elements or ingredients or quantities, as the use may be
in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Throughout this specification, the word “comprise”, or variations such as “comprises” or
“comprising” or “containing” or “has” or “having” wherever used, will be understood to imply
the inclusion of a stated element, integer or step, or group of elements, integers or steps, but
not the exclusion of any other element, integer or step, or group of elements, integers or steps.
Reference throughout this specification to “some embodiments”, “one embodiment” or “an
embodiment” means that a particular feature, structure or characteristic described in connection
with the embodiment may be included in at least one embodiment of the present disclosure.
Thus, the appearances of the phrases “in some embodiments”, “in one embodiment” or “in an
embodiment” in various places throughout this specification may not necessarily all refer to
the same embodiment. It is appreciated that certain features of the disclosure, which are, for
clarity, described in the context of separate embodiments, may also be provided in combination
in a single embodiment. Conversely, various features of the disclosure, which are, for brevity,
described in the context of a single embodiment, may also be provided separately or in any
suitable sub-combination.

The term “chromite ore tailings” as used herein refers to low-grade chromite ore obtained after
concentration of chromite ore. In some embodiments, chromite ore tailings comprise fines of
chromite ore comprising about 10-20% by weight of chromium oxide. In some embodiments,
chromite ore tailings comprise about 12-18% by weight of chromium oxide. In some
embodiments, chromite ore tailings may further comprise iron in the amount of about 20-30%
by weight, SiO2 in the range of about 25-35% by weight, Al2O3 in the amount of about 8-14%
by weight, MgO in the amount of about 1-5% by weight and loss on ignition (LOI) of about 8
to 10% by weight. LOI refers to volatile materials that are lost on heating. In some
embodiments, chromite ore tailings have a maximum particle size of 3 mm. In some
embodiments, 80% by weight of chromite ore tailings have a particle size in the range of about
100 µm to <25 µm. In some embodiments, chromite ore tailings have one or a combination of
the features described above.
The terms “sub-grade manganese ore” and “low-grade manganese ore” are used
interchangeably throughout this disclosure and refer to a manganese ore that comprises about
20-30% by weight of manganese oxide. In some embodiments, the low-grade manganese ore
comprises about 22-28% by weight of manganese oxide. In some embodiments, the low-grade
manganese ore may further comprise iron in the amount of about 30-40% by weight, SiO2 in
the amount of about 3-8% by weight, Al2O3 in the amount of about 2-6% by weight, and MgO
in the amount of about 1-3% by weight.
The term “about” as used herein encompasses variations of +/-10% and more preferably +/-
5%, as such variations are appropriate for practicing the present invention.
The present disclosure provides a method for preparing 200 series stainless steel scrap by
smelting chromite ore tailings, low-grade manganese ore, and a noble oxide. For smelting, each
of these components is prepared in the form of a pellet. To prepare a chromite-tailings pellet,
chromite ore tailings are mixed with a reducing agent, a fluxing agent, and a binder and the
mixture is pelletized. To prepare a low-grade manganese ore pellet, the low-grade manganese
ore is mixed with a reducing agent, a fluxing agent, and a binder and the mixture is pelletized.
To prepare a noble metal oxide pellet, the noble metal oxide is mixed with a binder and the
mixture is pelletized. Methods to pelletize ore or other raw materials by adding components
such as a reducing agent, a fluxing agent, and/or a binder are known in the art. The chromite
ore tailings pellet, the noble oxide pellet, and the low-grade Mn ore pellet are smelted in an arc

furnace in a specific order to obtain the 200 series stainless steel scrap. An exemplary schematic
of the process is shown in Figure 1.
Accordingly, in some embodiments, the method for preparing 200 series stainless steel scrap
comprises a) pelletizing a first mixture comprising chromite tailings, a reducing agent, a fluxing
agent, and a binder to obtain a chromite-tailings pellet; b) pelletizing a second mixture
comprising a noble metal oxide and a binder to obtain noble metal oxide pellets; c) pelletizing
a third mixture comprising low-grade manganese ore, a reducing agent, a fluxing agent, and a
binder to obtain a low-grade manganese ore pellet; d) adding the chromite-tailings pellet to an
arc furnace at a temperature of about 1500-1600˚C and allowing the chromite-tailings pellet to
melt to obtain a first molten mass; e) adding the noble metal oxide pellets into the first molten
mass and allowing the noble metal oxide pellets to melt to obtain a second molten mass; f)
adding the low-grade manganese ore pellet to the second molten mass and allowing the low-
grade manganese ore pellet to melt to obtain a third molten mass; and g) cooling the third
molten mass to obtain 200 series stainless steel scrap.
In some embodiments, the reducing agent employed to prepare the chromite tailings pellet and
manganese ore pellet is selected from coke, coal, or a carbonaceous material such as soot. In
an exemplary embodiment, coke is employed as the reducing agent. In some embodiments,
coke contains about 82-88% by weight of fixed carbon, about 0.5-1% by weight of volatile
matter, and about 10-14% by weight of ash. In some embodiments, the particle size of the coke
is less than 3 mm.
In some embodiments, the reducing agent is added to chromite tailings in an amount of about
12-17%, 12-16%, 13-17%, 13-16%, 13-15%, or 14-16%, including values and ranges thereof,
by weight of the chromite tailings. In some embodiments, the reducing agent is added to
chromite tailings in an amount of about 12, 13, 14, 15, 16, or 17, % by weight of the chromite
tailings.
In some embodiments, the reducing agent is added to low-grade Mn ore in an amount of about
15-22%, 15-20%, 17-22%, 17-21%, 18-22%, 19-22%, 19-23%, or 19-21%, including values
and ranges thereof, by weight of the low-grade Mn ore. In some embodiments, the reducing
agent is added to low-grade Mn ore in an amount of about 15, 16, 17, 18, 19, 20, 21, or 22 %
by weight of the low-grade Mn ore.

In some embodiments, the fluxing agent added to the chromite tailings pellet and manganese
ore pellet is lime or dolomite. In some embodiments, lime is hydrated lime or calcined lime. In
some embodiments, hydrated lime comprises about 55-68% by weight of CaO, about 1-8% by
weight of MgO, and about 1-8% by weight of SiO2.
The fluxing agent facilitates slag formation and maintains basic pH during smelting of pellets
in the furnace. In some embodiments, the fluxing agent provides a pH of about 0.8-1.2,
including values and ranges thereof. For example, the fluxing agent provides a pH of about
0.8-1.1, 0.8-1, 0.8-0.9, 0.9-1.2, 0.9-1.1, 0.9-1, 1-1.2, 1-1.1, including values and ranges thereof.
In some embodiments, the fluxing agent provides a pH of about 0.8, 0.9, 1, 1.1, or 1.2.
In some embodiments, the fluxing agent is added to chromite tailings in an amount of about
25-35%, 25-33%, 27-35%, 27-33%, 28-35%, 28-33%, 28-32%, 29-35%, 29-33%, 29-31%, 30-
35%, 30-33%, or 30-32%, including values and ranges thereof, by weight of the chromite
tailings. In some embodiments, the fluxing agent is added to chromite tailings in an amount of
about 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35% by weight of the chromite tailings. In an
exemplary embodiment, the fluxing agent is added to chromite tailings in an amount of about
30% by weight of the chromite tailings.
In some embodiments, the fluxing agent is added to low-grade Mn ore in an amount of about
1-5%, 1-4%, 1.5-4.5%, 1.5-3.5%, 2-5%, or 2-4%, including values and ranges thereof, by
weight of the low-grade Mn ore. In some embodiments, the fluxing agent is added to low-grade
Mn ore in an amount of about 1, 2, 3, 4, or 5% by weight of the low-grade Mn ore.
Table 1 shows an exemplary chemical composition of chromite tailings, low-grade Mn ore,
coke (reducing agent) and lime (fluxing agent).
Table 1: Chemical composition of raw materials (wt%)



In some embodiments, the binder employed to prepare the chromite tailings pellet, the noble
metal oxide pellet, and the manganese ore pellet is selected from a group comprising bentonite,
dextrin, cement, a cementitious material, or a slag. Examples of cementitious materials include,
but are not limited to, fly ash and ground granulated blast furnace slag (GGBFS). In an
exemplary embodiment, the binder is bentonite.
In some embodiments, the binder is added to a pellet composition comprising chromite tailings,
the binder, a reducing agent, and a fluxing agent in an amount of about 1-2%, including values
and ranges thereof, by weight of the pellet composition.
In some embodiments, the binder is added to a pellet composition comprising low-grade Mn
ore, the binder, a reducing agent, and a fluxing agent in an amount of about 1-2%, including
values and ranges thereof, by weight of the pellet composition.
In some embodiments, the binder is added to a pellet composition comprising noble metal oxide
and the binder in an amount of about 1-2%, including values and ranges thereof, by weight of
the pellet composition.
In some embodiments, the noble metal oxide employed to prepare the noble metal oxide pellet
is selected from copper oxide, silver oxide, rhenium oxide, ruthenium oxide, rhodium oxide,
palladium oxide, osmium oxide, iridium oxide, platinum oxide, and gold oxide. In an
exemplary embodiment, the noble metal oxide is copper oxide.
To prepare the pellets, chromite tailings, low-grade Mn ore, noble metal oxide, reducing agent,
and fluxing agent are subject to grinding and passed through desired mesh sizes. For example,
in some embodiments, coke is ground to have at least 80% particles in the size of <3mm, lime
is ground to have at least 80% particles in the size of (<75µm) and chromite tailings and sub-
grade manganese ore is ground to have at least 80% particles in the size of <25µm. Ground

chromite tailings are mixed with a reducing agent (e.g., coke), a fluxing agent (e.g., lime) and
a binder (e.g., bentonite) and the mixture is pelletized with a moisture ranging from about 10-
20% to obtain a chromite tailings pellet. Ground low-grade Mn ore is mixed with a reducing
agent (e.g., coke), a fluxing agent (e.g., lime) and a binder (e.g., bentonite) and the mixture is
pelletized with a moisture ranging from about 10-20% to obtain a low-grade Mn ore pellet.
Ground noble metal oxide is mixed with a binder (e.g., bentonite) and the mixture is pelletized
with a moisture ranging from about 10-20% to obtain a noble metal oxide pellet. The pellets
are dried, for example, in an oven, at about 150˚C. In some embodiments, the pellets are dried
at about 150˚C for about 4 hours. In some embodiments, a moisture content of about 10-18%,
10-16%, 12-18%, or 13-17% is provided while preparing the pellets by adding water.
The pellets are charged into an arc furnace in a specific order for smelting of the ores. First the
chromite tailings pellet is added to the furnace and allowed to melt at a temperature of about
1500-1600℃ to obtain a first molten mass. The noble metal oxide pellets are added to the first
molten mass and allowed to melt to provide a second molten mass. After the reduction of
chromite tailings is complete (which is around 5-10 mins post charging), the low-grade Mn ore
pellet is added to the second molten mass and allowed to melt to provide a third molten mass.
Throughout the addition of the pellets, the temperature of the arc furnace is maintained at about
1500-1600˚C, including values and ranges thereof. In some embodiments, the temperature of
the furnace is maintained at about 1500-1590˚C, 1500-1580˚C, 1500-1575˚C, or 1500-1550˚C,
including values and ranges thereof. In an exemplary embodiment, the temperature of the
furnace is maintained at about 1500-1550˚C throughout the smelting process.
In some embodiments, the third molten mass is held in the arc furnace for about 15 to 25
minutes prior to cooling.
After smelting of the ores is complete, the third molten mass is allowed to cool. The cooled
mass (referred to as “cake”) comprises metal part and slag part. The metal and slag parts are
physically separable and can be recovered by breaking the cakes. The metal part is 200-series
stainless steel scrap.
The arc furnace employed in smelting of the ores can be electric arc furnace or submerged arc
furnace.

In some embodiments, the 200-series stainless steel scrap obtained by the method disclosed
herein comprises iron in the amount of about 55-82% by weight, chromium in the amount of
about 12-25% by weight, silicon in the amount of about 0.2-2.5% by weight and carbon in the
amount of about 2-7% by weight.
In some embodiments, the 200-series stainless steel scrap comprises iron in the amount of about
58-72%, 60-75%, or 60-72% by weight. In some embodiments, the 200-series stainless steel
scrap comprises chromium in the amount of about 12-22%, 12-20%, 13-21%, 13-20%, or 14-
20% by weight. In some embodiments, the 200-series stainless steel scrap comprises silicon in
the amount of about 0.5-2% by weight. In some embodiments, the 200-series stainless steel
scrap comprises carbon in the amount of about 3-6% by weight. In some embodiments, the
200-series stainless steel scrap comprises manganese in the amount of about 3-13%, 4-12%, or
5-11% by weight. In some embodiments, the 200-series stainless steel scrap comprises nickel
in the amount of about 0.5-2.5% or about 1-2% by weight. In some embodiments, the 200-
series stainless steel scrap comprises the noble metal from the noble metal oxide in the amount
of about 0.5-5%, 0.5-4.5%, 0.5-4%, 1-5%, 1-4%, or 2-5% by weight. The 200-series stainless
steel scrap provided by the methods of the present disclosure comprises any combination of
the above-described amounts of iron, chromium, silicon, carbon, manganese, nickel, and noble
metal.
In some embodiments, the slag obtained along with the 200-series stainless steel scrap
comprises CaO in the amount of about 20-35% by weight, MgO in the amount of about 2-10%
by weight, SiO2 in the amount of about 25-38% by weight, Al2O3 in the amount of about 12-
28% by weight, MnO in the amount of about 2-10% by weight, FeO in the amount of about 2-
6% by weight and Cr2O3 in the amount of about 1-4% by weight.
In some embodiments, the slag comprises CaO in the amount of about 20-33%, 22-35%, 22-
33%, 24-33%, or 25-33% by weight. In some embodiments, the slag comprises MgO in the
amount of about 2-9%, 2-8%, 3-10%, 3-9%, 3-8%, 4-10%, or 4-8% by weight. In some
embodiments, the slag comprises SiO2 in the amount of about 26-37%, 26-36%, 26-35%, 26-
34%, 28-36 or 28-35% by weight. In some embodiments, the slag comprises Al2O3 in the
amount of about 12-26%, 13-26%, 14-28%, 14-25%, 14-20%, or 15-20% by weight. In some
embodiments, the slag comprises MnO in the amount of about 2-9%, 2-8%, 2-6%, 2-5%, 3-
10%, 3-9%, 3-8%, 3-6%, or 3-5% by weight. In some embodiments, the slag comprises FeO

in the amount of about 1-5%, 1-4%, 2-5%, or 2-4% by weight. In some embodiments, the slag
comprises Cr2O3 in the amount of about 2-4% by weight. The slag produced along with the
200-series stainless steel scrap in the methods of the present disclosure comprises any
combination of the above-described amounts of CaO, MgO, SiO2, Al2O3, MnO, FeO and
Cr2O3.
The present disclosure also provides use of chromite tailings in preparation of 200 series
stainless steel scrap. The chromite tailings are as defined herein.
The present disclosure also provides use of low-grade manganese ore in preparation of 200
series stainless steel scrap. The low-grade manganese ore is as defined herein.
The method for producing 200-series stainless steel scrap of the present disclosure provides
many advantages. The present method is a low temperature and low energy process than
conventional stainless steel and ferrochrome production. Specifically, the present method
comprises smelting of the ores at about 1500-1600˚C, preferably at about 1500-1550˚C. The
temperature required for smelting of ores in the present method is lower than that used in
conventional stainless-steel production process as the present method employs low grade
materials. The melting point of the ore increases with an increase in the grade of the ore. Lower
grade ore has lower melting point, because of low metallic value associated with it. Thus, the
present method is carried out at lower temperatures than conventional stainless steel or
ferrochrome production methods which typically involve temperature above 1600˚C. Since the
temperature required is lower, the process requires less power input to carry out the smelting.
Therefore, the process is a low energy process. Further, the method employs otherwise
discarded metal ore waste to produce 200-series stainless steel scrap. That is, the method uses
inexpensive raw materials and in fact, mitigates the environmental concerns associated with
the metal ore waste. Thus, the present disclosure provides a simple and cost-effective method
to produce a valuable starting product (200-series stainless steel scrap) from discarded metal
ore waste.
It is to be understood that the foregoing descriptive matter is illustrative of the disclosure and
not a limitation. While considerable emphasis has been placed herein on the particular features
of this disclosure, it will be appreciated that various modifications can be made, and that many
changes can be made in the preferred embodiments without departing from the principles of

the disclosure. Those skilled in the art will recognize that the embodiments herein can be
practiced with modification within the spirit and scope of the embodiments as described herein.
Similarly, additional embodiments and features of the present disclosure will be apparent to
one of ordinary skill in art based upon description provided herein.
Descriptions of well-known/conventional methods/steps and techniques are omitted so as to
not unnecessarily obscure the embodiments herein. Further, the disclosure herein provides for
examples illustrating the above described embodiments, and in order to illustrate the
embodiments of the present disclosure certain aspects have been employed. The examples used
herein for such illustration are intended merely to facilitate an understanding of ways in which
the embodiments herein may be practiced and to further enable those of skill in the art to
practice the embodiments herein. Accordingly, the following examples should not be construed
as limiting the scope of the embodiments herein.
EXAMPLES
Example 1: Preparation of 200-series stainless steel scrap
To prepare a chromite tailings pellet, 750 gm of chromite tailings, 225 gm of lime, 110 gm of
coke and 9.70 gm of bentonite were blended to make the charge mix. Sufficient water was
added to make the moisture content to 14% followed by pelletizing. To make sub-grade
manganese ore pellet, 325 gm Mn ore, 65 gm coke, 10 gm lime and 4 gm bentonite were mixed,
sufficient water was added to make the moisture content to 14%, and the mixture was
pelletized. Further 8 gm cupric oxide was mixed with 0.1 gm bentonite, sufficient water was
added to make the moisture content to 14% and the mixture was pelletized. The formed pellets
were oven dried at 150˚C for 4 hrs. The pellets were taken for smelting, first the chromite
tailing pellet was charged and allowed to melt, followed by addition of cupric oxide pellet
followed by addition of sub-grade manganese ore pellets. During smelting, the operation time
consisted of (a) heating the furnace crucible for 30 min (b) charging the raw material for 10-20
min (c) holding or soaking for 15-25 min. The heating of the crucible was done by arcing
between electrode and coke at bottom. Charging of raw materials into the crucible was started
after it attained the desired temperature. The raw materials were added slowly to the crucible
in small quantities and the charging operation completed in 10-20 minutes. During experiment
the operation temperature was maintained at 1550±50˚C and monitored by infrared pyrometer.

A holding time or soaking time of 15-25 min was allowed to the molten mass. Molten slag and
metal were allowed to cool inside the furnace after completion of the smelting. The metallic
and non-metallic (slag) parts were physically separable and were recovered by breaking the
cakes. The metallic part is 200- series stainless steel scrap and its composition was: Si- 0.78
wt%, Fe-71.06 wt%, Cr2O3- 14.20 wt%, Ni-1.12 wt%, C-5.7 wt%, Mn- 5.56 wt%, Cu-2.3 wt%.
The slag obtained with the 200-series stainless steel scrap had a composition of: CaO-24.92,
MgO-3.72 wt%, Al2O3-13.2 wt%, SiO2-35.07 wt%, MnO-3.72 wt%, FeO- 3.42 wt%.
Example 2: Preparation of 200-series stainless steel scrap
To prepare a chromite tailings pellet, 700 gm of chromite tailings, 210 gm of lime, 98 gm of
coke and 9.75 gm of bentonite were blended to make the charge mix. Sufficient water was
added to make the moisture content to 16% and the mixture was pelletized. Sub-grade
manganese ore pellet was made by mixing 300 gm sub-grade manganese ore, 6 gm lime, 57
gm coke, 3.5 gm bentonite, with moisture content of 16 wt%. Further 7.2 gm cupric oxide was
mixed with 0.08 gm bentonite, sufficient water was added to make the moisture content to 10
wt%, and the mixture was pelletized. The formed pellets were oven dried at 150℃ for 4 hrs
post which they were charged in the submerged arc furnace in the order. The charging of the
materials, the smelting conditions in the arc furnace and slag/metal separation were conducted
in a manner similar to Example 1. The 200-series stainless steel scrap had a composition of:
Si-1.8 wt%, Fe-60.8 wt%, Cr-20.5 wt%, Al-0.68 wt%, Ni-1.198 wt%, Cu- 1.36 wt%, Mn-10.35
wt%, C-3.83 wt%. The composition of the slag was: CaO-32.8 wt%, MgO-8.2 wt%, Al2O3-
25.5 wt%, SiO2- 28.9 wt%, MnO-4.52 wt%.

We Claim:
1. A method for preparing 200 series stainless steel scrap, said method comprising:
a. pelletizing a first mixture comprising chromite tailings, a reducing agent, a
fluxing agent, and a binder to obtain a chromite-tailings pellet;
b. pelletizing a second mixture comprising a noble metal oxide and a binder to
obtain noble metal oxide pellets;
c. pelletizing a third mixture comprising low-grade manganese ore, a reducing
agent, a fluxing agent, and a binder to obtain a low-grade manganese ore pellet;
d. adding the chromite-tailings pellet to an arc furnace at a temperature of about
1500-1600℃ and allowing the chromite-tailings pellet to melt to obtain a first
molten mass;
e. adding the noble metal oxide pellets into the first molten mass and allowing the
noble metal oxide pellets to melt to obtain a second molten mass;
f. adding the low-grade manganese ore pellet to the second molten mass and
allowing the low-grade manganese ore pellet to melt to obtain a third molten
mass; and
g. cooling the third molten mass to obtain 200 series stainless steel scrap.
2. The method as claimed in claim 1, wherein the arc furnace is an electric arc furnace or
submerged arc furnace.
3. The method as claimed in claim 1, wherein the temperature of the arc furnace is 1500-
1550˚C.
4. The method as claimed in claim 1, wherein the chromite-tailings pellet, the noble metal
oxide pellets and the low-grade manganese ore pellet are dried in an oven at about
150˚C prior to adding to the arc furnace.
5. The method as claimed in claim 1, wherein the third molten mass is held in the arc
furnace for about 15 to 25 minutes prior to cooling.
6. The method as claimed in claim 1, wherein the chromite tailings is a chromite ore
comprising about 10-20% by weight of chromium oxide.
7. The method as claimed in claim 6, wherein the chromite ore comprises iron in the
amount of about 20-30% by weight, SiO2 in the range of about 25-35% by weight,
Cr2O3 in the amount of about 12-18% by weight, Al2O3 in the amount of about 8-14%
by weight, MgO in the amount of about 1-5% by weight and loss on ignition (LOI) of
about 8 to 10% by weight.

8. The method as claimed in claim 1, wherein the chromite tailings have a maximum
particle size of 3 mm.
9. The method as claimed in claim 8, wherein the chromite tailings have a particle size in
the range of about 100 to <25 µm.
10. The method as claimed in claim 1, wherein the noble metal oxide is selected from the
group consisting of: copper oxide, silver oxide, rhenium oxide, ruthenium oxide,
rhodium oxide, palladium oxide, osmium oxide, iridium oxide, platinum oxide, and
gold oxide.
11. The method as claimed in claim 10, wherein the noble metal oxide is cupric oxide.
12. The method as claimed in claim 1, wherein the low-grade manganese ore is a
manganese ore comprising about 20-30% by weight of manganese oxide.
13. The method as claimed in claim 12, wherein the low-grade manganese ore comprises
iron in the amount of about 30-40% by weight, SiO2 in the amount of about 3-8% by
weight, MnO in the amount of about 22-28% by weight, Al2O3 in the amount of about
2-6% by weight and MgO in the amount of about 1-3% by weight.
14. The method as claimed in claim 1, wherein the reducing agent is selected from coke,
coal, or a carbonaceous material.
15. The method as claimed in claim 1, wherein the fluxing agent is selected from lime or
dolomite.
16. The method as claimed in claim 15, wherein the lime is hydrated lime or calcined lime.
17. The method as claimed in claim 16, wherein the hydrated lime comprises CaO in the
amount of about 55-68% by weight, MgO in the amount of about 1-8% by weight and
SiO2 in the amount of about 1-8% by weight.
18. The method as claimed in claim 1, wherein the binder is selected from a group
comprising bentonite, dextrin, cement, a cementitious material, or a slag.
19. The method as claimed in claim 1, wherein the 200 series stainless steel scrap comprises
iron in the amount of about 60-82% by weight, chromium in the amount of about 12-
25% by weight, silicon in the amount of about 0.2-2.5% by weight and carbon in the
amount of about 2-7% by weight.
20. The method as claimed in claim 1, wherein a metal slag obtained along with the 200
series stainless steel scrap comprises CaO in the amount of about 20-35% by weight,
MgO in the amount of about 2-10% by weight, SiO2 in the amount of about 25-38% by
weight, Al2O3 in the amount of about 12-28% by weight, MnO in the amount of about

2-10% by weight, FeO in the amount of about 2-6% by weight and Cr2O3 in the amount
of about 1-4% by weight.
21. A 200 series stainless steel scrap obtained by the method as claimed in any one of claims
1-20.
22. Use of chromite tailings in preparation of 200 series stainless steel scrap.
23. The use as claimed in claim 22, wherein the chromite tailings is a chromite ore
comprising about 10-20% by weight of chromium oxide.
24. The use as claimed in claim 22, wherein the chromite ore comprises iron in the amount
of about 20-30% by weight, SiO2 in the range of about 20-26% by weight, Cr2O3 in the
amount of about 12-18% by weight, Al2O3 in the amount of about 8-14% by weight,
MgO in the amount of about 1-5% by weight and loss on ignition (LOI) of about 8 to
10% by weight.
25. Use of low-grade manganese ore in preparation of 200 series stainless steel scrap.
26. The use as claimed in claim 25, wherein the low-grade manganese ore is a manganese
ore comprising about 20-30% by weight of manganese oxide.
27. The use as claimed in claim 25, wherein the low-grade manganese ore comprises iron
in the amount of about 30-40% by weight, SiO2 in the amount of about 3-8% by weight,
MnO in the amount of about 22-28% by weight, Al2O3 in the amount of about 2-6% by
weight, and MgO in the amount of about 1-3% by weight.