FIELD OF THE INVENTION
The invention relates to the minimization of the iron ore dust from agglomerates
and effective utilization of waste polymers in the process of agglomeration. More
specifically, the process provides a method of in-situ encapsulation of the iron
ore pellets in an induration furnace during pelletizing.
BACKGROUND OF THE INVENTION
Iron ore agglomerates such as sinter and pellets are used as raw materials for
iron production. Huge amount of dust generation takes place while handling
• these agglomerates from agglomeration unit to the iron making unit. This results
in loss of mineral values and environmental pollution due to dust. Abrasion is
considered to be the main reason for the dust generation. Many attempts have
been made in the past to enhance the strength and to lower the dust generation
of the iron ore pellets by optimizing the additives content, reductants, firing
temperature, pellets size etc. (Ref 1 to Ref 5)- However, not much is reported on
to reduce the abrasion from the agglomerate surface.
Increasing quantity of waste polymers in the environment is a known threat to
the society. Various ways of waste polymer utilization and recycling were placed
up to the commercial scale (ref. 6 to 9) but unfortunately 21-32 % of polymer
was recycled (ref. 10) in UK in 2010 and in India situation is even more severe,
as huge volume of polymer is converted into waste (ref 11). This posed problem
become severe when the waste polymer comes from the food industries because
in food processing industries always virgin polymers were preferred over the
recycled one. Effective utilization of the waste polymer is still an unsolved

problem. Many attempts have been made to make use of the waste polymer in
metallurgical industries. An attempt was made as described in patent
WO2004099452 (Ref 12) to coat the emulsion of polymer and water over iron
ore pellets to increase the abrasion resistance. But only spray coating technique
was preferred over others. Further, external polymer conditioning and emulsion
preparation requires additional energy, a complete new setup is also required for
pellet coating that add to cost and time of pellet production.
It was also well illustrated by Matsuda et. al (Ref 13) that the waste plastics can
be used as a reductant for Fe2O3. But no other attempt was made to study the
effect of waste polymers like PET (Poly ethylene terephthalate), PP (Poly
propylene), PS (Poly styrene) etc. on the agglomerates reduction in any smelting
furnaces. Only PE (poly ethylene) and tar were studied by developing a
composite with Fe2O3 and no effort was made for polymer coating of the Fe2O3
composite.
Waste polymer direct injection into the blast furnace was also tried in furnace to
substitute the coke as a reducing agent for iron making. (Ref. 14). But the field of
pellet encapsulation by waste plastics is not entirely explored. There is need to
devise a method and process that can overcome the limitations of prior at in
terms of energy reduction and efficiency. Utilization of other waste polymeric
materials like PET (polyethylene terephthalate), PP (poly propylene), PS (poly
styrene) etc. for in-situ encapsulation during pelletizing using available heat in
induration furnaces is still there. Better and efficient technique can be developed
and optimized for coating of the agglomerates.

OBJECT OF THE INVENTION
An object of the invention is to develop a process for improvising quality of iron
oxide pellets.
Another object of the invention is to make use of waste polymers for
encapsulating iron oxide pellets.
Still another object of the invention is to utilize heat available in the induration
furnace for melting the waste polymers.
A further object of the invention is to develop a process of encapsulating iron
oxide pellets by waste polymers using the conventional set-up of an Induration
furnace.
SUMMARY OF THE INVENTION
The present innovation targets to improvise quality of iron oxide pellets by
making use of waste plastic and the heat available in the induration furnace
during pelletizing. Waste Polymer Encapsulated Pellets (WPEP's) are new
category of raw materials, which can be used for iron production. In terms of
quality, WPEPs show tremendous potential, as WPEP has 95% higher abrasion
resistance and 10% higher cold compression strength as compared to the
conventional pellets. This leads to minimal shattering and lower dust generation
while handling of agglomerates. A novel approach has been designed to coat the
pellets with waste shredded polymeric material by spreading those miniature
polymeric pieces over the hot pellet surface during the cooling cycle of pellet
preparation inside the induration furnace. Customized charging system is devised

for the spreading of the polymeric material over the pellet bed in the induration
furnace (fig. 1). Swing arrangement was made in the upper and lower portion of
the cooling zone number 2 of induration furnace to deflect the updraft gas in
different chamber during charging of the polymeric material over pellets. Certain
frequency was set for the dumping of the shredded polymeric materials on the
pellet bed. To device uniform and smooth coating over pellets, temperature for
covering was optimized to 350°C-500°C, which leads to development of plastic
layer of 120-150um and diffused polymeric layer of 20-40um (fig 2). This
polymeric layer fills the surface pores and arrest the surface cracks and result in
better abrasion resistance. Layered pellets are intendant to get cooled inside the
induration furnace under controlled conditions. To coat the pellets, the carry over
heat of pellets is used and no additional energy is required for melting of the
waste polymers which finally results in the development of waste polymer
encapsulated pellets.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig 1: Process flow for the preparation of WPEP (Waste Polymer Encapsulated
Pellets).
Fig 2: Schematic of a WPEP (waste polymer encapsulated pellet).
Fig 3: Temperature profile inside the Induration furnace.

DETAILED DESCRIPTION OF THE INVENTION
Iron ore of +8mm is used as raw material for the pig iron production in smelting
furnaces. Iron ore of +8mm size is preferred to avoid furnace irregularities due
to chocking of fines in the furnace. Iron bearing minerals of less than 8 mm size
are agglomerated to make them usable for reduction in smelting furnaces. Iron
ore pellets and sinter are two agglomerates used as raw materials for iron
production. Iron ore pellets are prepared to make use of the very fine iron
bearing materials. Pelletizing and sintering is performed in strong oxidizing
condition. In pelletizing fine iron ore, fluxes, binder and moisture are first mixed
and green pellets are prepared in the disc or drum pelletizer. The green pellets
are fired in the induration furnace to give proper strength to the pellets. In
induration furnace the pellets are fired up to 1350°C to develop proper strength
(fig. 3).
During pellet firing in induration furnace, in situ fusion and slag formation takes
place. Then while cooling in the comparatively colder part of the furnace,
solidification of slag melt occurs and results in better strength of the pellets.
Thereafter, the pellets are transported to the iron making units, while handling
these agglomerates suffers abrasion, chipping and shattering due to the poor
surface and chemical properties. Pellets surface mineral grains are more
vulnerable to the abrasion. Present invention focus on the enhancement of the
abrasion strength and CCS (cold compression strength) of Iron ore pellets by
optimal usage of the waste polymers and heat available in induration furnace
during pelletizing.

charging of the waste polymers in to the induration furnace, the blanking plate
was placed below the cooling zone number 2 in DF position to direct the gas and
isolating plate also swings below in AB position to isolate the cooling chamber
number 2 from rest of the induration furnace. Once the charging is done,
isolating plate and blanking plate were moved back to their normal position AC
and DE respectively for the proper cooling of the pellets.
Shredded waste polymeric material takes carry over heat of the pellets in cooling
zone 2 of induration furnace and result in in-situ melting and softening of
polymers inside the furnace. Melted polymer diffuse to the pellets from the
surface pores, after cooling polymer form a uniform outer and diffused layer in
pellet. Spreading of this shredded polymeric material has to be done at 350°C-
500°C in oxidizing condition for the development of the optimized polymeric layer
of 120-150um thick over the pellets.
Fig 2 shows the schematic view of the cross section of a WPEP (Waste polymer
encapsulated pellet). Three distinct layers can be seen in the WPEP. Approximate
thickness of the outer most polymer layer is around 120-150 urn. Next
immediate layer was formed by the diffusion of the polymer from surface pores.
Approximate thickness of the diffused polymeric layer was around 20-40 urn. The
pellet core is free from polymer. The outer most polymeric layer and
intermediate diffused polymer layer help to resist against abrasion and increase
the cold compression strength.
Cold compression strength of pellets is measured in CCS machine by following
ISO 4700 method and about 10% enhancement in the Cold strength of WPEP
was observed as compared to the conventional iron ore pellet. Similarly abrasion

resistance of the WPEP was also measured by ISO 3271 and about 95%
enhancement in the abrasion resistance is observed as compared to the
conventional iron ore pellets. Optical characterization reveals that the
enhancement in the CCS and the abrasion resistance is due to presence of outer
polymeric layer and diffused polymeric layer, which prevent the outer surface of
pellets from abrasion. Waste polymeric materials like polyethylene, polystyrene,
polypropylene.
These especially designed waste polymer encapsulated pellets (WPEPs) are used
as the raw materials for smelting in blast furnace. The polymer covering over the
pellets prevent the shattering of pellets while handling and dumping inside the
furnace for smelting. WPEPs give advantage in fuel rate reduction as polymer
coated over the pellets act as the fuel for smelting. In blast furnace route of Iron
making various furnace productivity enhancement techniques like high top
pressure, humidification of the blast, coal injection are common nowadays. In
that line usage of WPEPs as raw material in blast furnace will result in high
pressure in the upper part of the furnace due to the softening and melting of the
polymers in upper zone of blast furnace, which result in more residence time for
the upcoming gases and hence, lead to more indirect reduction of the iron
bearing material. This above stated phenomenon will result in fuel rate reduction
and enhancement in blast furnace productivity. Calculations performed on CO2
emission during the usage of WPEPs as raw material for pig iron production,
about 8% decrease in the CO2 emission/ metric ton of pig iron was estimated.
WPEPs has shown strong potential for the waste polymer usage, about 100-300
kg of waste polymer can be used for the production of one ton of WPEPs.

References
1. Influence of Pellet Size on Quality and Microstructure of Iron Ore
Pellets, Srinivas DWARAPUDI, T. Uma DEVI S. MOHAN RAO and Madhu RANJAN,
ISIJ International, Vol. 48 (2008), No. 6, pp. 768-776
2. The Effect of Additives and Reductants on the Strength of Reduced Iron Ore
Pellet. R. C. GUPTA and J. P. GAUTAM, ISIJ International, Vol. 43 (2003), No. 12,
pp. 1913-1918.
3. Influence of Pellet Basicity (CaO/SiO2) on Iron Ore Pellet Properties and
Microstructure. T. UMADEVI, Prasanna KUMAR, Naveen F. LOBO, M. PRABHU,
P.C. MAHAPATRA and Madhu RANJAN. ISIJ International, Vol. 51 (2011), No. 1,
pp. 14-20.
4. Interactions between Iron Oxides and the Additives Quartzite, Calcite and
Olivine in Magnetite based Pellets. Par SEMBERG, Anders RUTQVIST, Charlotte
ANDERSSON arid Bo BJORKMAN. ISIJ International, Vol. 51 (2011), No. 2, pp.
173-180.

5. Optimization of Firing Temperature for Hematite Pellets Tekkalakote
UMADEVI, Naveen Frank LOBO, Sangamesh DESAI, Pradipta Chandra
MAHAPATRA, Rameshwar SAH and Manjunath PRABHU. ISIJ International, Vol.
53 (2013), No. 9, pp. 1673-1682.
6. CONVERTING WASTE PLASTICS INTO A RESOURCE, Compendium of
Technologies, United Nations Environmental Programme, 2009.
7. Website Material on Plastic Waste Management, Central Pollution Control
Board, June, 2013.
8. Plastics recycling: challenges and opportunities, Jefferson Hopewell, Robert
Dvorak and Edward Kosior, Phil. Trans. R. Soc. B (2009) 364, 2115-2126.
9. Utilization of Waste Plastic as a Strength Modifier in Surface Course of Flexible
and Rigid Pavements Afroz Sultana.SK, K.S.B.Prasad, International Journal of
Engineering Research and Applications, Vol. 2, Issue 4, July-August 2012,
pp.1185-1191.

10. UK Plastics Waste - A review of supplies for recycling, global market
demand, future trends and associated risks. Final Report-Material change for
better environment. Published by- Waste and resources action programme.
November 2006.
11. Material on Plastic Waste Management, Central Pollution Control Board, June
2012.
12. WO2004099452 (Assignee-Samarco Mineracao S A; Oliveira Fonseca
Vinicius; Otaviano Mauricio Marcos; Cota Fonseca Mauricio; Da Silva Lopes
Flavio)
13. Utilization of Waste Plastic for the Production of Metallic Iron, Hydrogen and
Carbon Monoxide without Generating Carbon Dioxide.
Takehito MATSUDA, Masakatsu HASEGAWA, Akiyoshi IKEMURA, Kazumasa
WAKIMOTO and Masanori IWASE, ISIJ International, Vol. 48 (2008), No. 9, pp.
1188-1196.
14. Recycling of Waste Plastic Packaging in a Blast Furnace System. Yoji Ogaki,
Koichi Tomioka, Atsushi Watanabe, Koji Arita, Ichiro Kuriyamka and Tetsuro
Sugayoshi. NKK TECHNICAL REVIEW No. 84(2001) 1

WE CLAIM:
1. A method of encapsulating ore agglomerates with a polymer layer, the
method comprising:
shredding polymers into pieces using a shredder to get a particle
size ranging from 0.1 mm to 250 mm; and
charging the shredded polymer pieces of size 0.1 to 250 mm in to a
cooling zone (cooling zone 2) of an induration furnace via a
polymer charging system, the shredded polymer pieces being
melted using the carry over heat of the ore agglomerates from a
firing zone of the induration furnace.
2. The method as claimed in claim 1 further comprising the step of drifting
the air flow from a cooling fan towards cooling zone 1 during charging of
the shredded polymer pieces in to the cooling zone 2, the cooling zone 2
being blocked by a swinging blanking plate to stop the air flow during
charging of the shredded polymer pieces in to the cooling zone 2.
3. The method as claimed in claim 1 wherein temperature of cooling zone 2
in the induration furnace is in the range of 350°C-500°C.
4. The method as claimed in claim 1 wherein the polymers are waste
polymers.
5. The method as claimed in claim 4 wherein one ore more waste polymers
are selected from the group comprising polyethylene, low density
polyethylene, poly propylene, poly styrene, acrylic polymers, vinyl acetate
polymers, and Poly ethylene terephthalate (PET).

6. The method as claimed in claim 1 wherein the ore agglomerates are iron
ore agglomerates.
7. The ore agglomerates prepared as per the process claimed in claim 1 to
claim 6 wherein the abrasion resistance of the ore agglomerates increases
by 95% and cold compression strength increases by 10 % as per ISO
3271 and ISO 4700 methods respectively.
8. The ore agglomerates as per any of the preceding claims wherein the ore
agglomerates comprises three layers: an inner pellet core layer, an outer
diffused polymeric layer and an outermost polymeric layer.
9. The ore agglomerates as per the claim 8 wherein thickness of the outer
diffused polymer layer varies in the range of 20-40 urn.
10. The ore agglomerates as per the claim 8 wherein thickness of the
outermost polymer layer varies in the range of 120-150 urn.
11. An induration furnace with a polymer charging system attached at cooling
zone 2 and a swinging blanking plate to stop the air flow during charging
of the shredded polymer pieces in to the cooling zone 2.

ABSTRACT

The invention relates to an WPEP's Waste Polymer Encapsulated Pellets are
developed by effectively utilizing the waste polymers and carry over heat of pre-
cooked pellets in an induration furnace during pelletizing. Waste polymer
encapsulated pellets has shown strong character to reduce industrial dust
emission as WPEP has 95% higher abrasion resistance and 10% higher cold
compression strength as compared to the conventional pellets. WPEP usage in
iron production will result in reduction of environmental polymeric solid waste
and metallurgical fuel requirement. The process involves making design
modification in the induration furnace where a polymer charging system is
attached to the cooling zone 2 of the induration furnace and a swinging blanking
plate is attached on the lower side to stop the air flow during charging of the
shredded polymer pieces in to the cooling zone 2.