Bouguer Gravity Regional and Residual Separation: Application to Geology and Environment [thesis]

43 Pages·2012·0.407 MB·English

by  K. Mallick, A. Vasanthi, K.K. Sharma

EFFECT OF SIZE DISTRIBUTION AND WATER CONTENT
ON PROPERTIES OF IRON ORE PELLETS

A THESIS SUBMITTED IN PARTIAL FULFILLMENT
OF THE REQUIREMENT FOR THE DEGREE OF

Bachelor of Technology
in
Metallurgical and Materials Engineering

BY
MAHESH GOENKA (109MM0440)
ABHISHEK NAIK (109MM0450)
Under the guidance of

DR. SMARAJIT SARKAR

Department of Metallurgical and Materials Engineering
National Institute of Technology Rourkela
2013
NATIONAL INSTITUTE OF TECHNOLOGY ROURKELA

CERTIFICATE

This is to certify that the thesis entitled “EFFECT OF FINE SIZE AND
WATER CONTENT ON PROPERTIES OF IRON ORE PELLETS”
submitted by Abhishek Naik (109MM0450) and Mahesh Goenka
(109MM0440) in partial fulfilment of the requirements for the award of
Bachelor of Technology Degree in Metallurgical and Materials Engineering
at National Institute of Technology, Rourkela is an original work carried out
by them under my supervision and guidance.

The matter embodied in the thesis has not been submitted to any other
University/ Institute for the award of any degree.

Date: Prof. Smarajit Sarkar,
Dept. of Metallurgical &
Materials Engineering,
National Institute of Technology,
Rourkela-769008

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ACKNOWLEDGEMENT
We express our sincere gratitude to the Department of Metallurgical and
Materials Engineering, NIT Rourkela for giving us an opportunity to work on
this project and allowing us access to valuable facilities in the department.
We avail this opportunity to express our indebtedness to our guide Dr. Smarajit
Sarkar, Associate Professor, Department of Metallurgical and Materials
Engineering, NIT Rourkela, for his valuable guidance, constant encouragement
and kind help at various stages for the execution of this dissertation work.
We would like to convey our heartfelt gratitude to Mr. Chandra Shekhar Dey to
whom we are indebted for his relentless support and timely guidance during our
project work.
We are also grateful to Mr. Bhanja Naik, Department of Metallurgical and
Materials Engineering, NIT Rourkela for providing valuable assistance and
insight during the experimental process.

Date: 9th May, 2013
Mahesh Goenka (109MM0440)
Abhishek Naik (109MM0450)
Department of Metallurgical and Materials Engineering,
National Institute of Technology, Rourkela
Rourkela-769008
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ABSTRACT
Iron ore fines are converted to iron by the following route:
Fines  Pellets  Reduction to metallic Fe
Therefore, the process of formation of pellets has to ensure that its product has
required properties to perform as desired during the stage of reduction. This
thesis, and the work done as recorded, aims at identifying the optimum values
of properties of the chief raw materials of pelletization: iron ore fines and water
(moisture) so that the prepared pellets exhibit maximum productivity.
The size distribution and water content of the pellets need to be studied and
correlated to such pellet properties as strength, percentage reduction and
swelling during reduction to obtain relationships between these factors. These
results can be used for adopting the most suitable values of process parameters
in industrial pelletization.

Keywords: Size distribution, Water Content, Green Strength, Swelling,
Reduction Behaviour
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TABLE OF CONTENTS
Index Content Page
Bonafide Certificate 1
Acknowledgement 2
Abstract 3
List of Tables 6
List of Tables 7

Chapter 1: Introduction 8 – 13
1.1 Introduction to Pelletizing
1.2 Definition of Pelletization
1.3 Pelletization: Advantages
1.4 Challenges faced by Pelletization Process
1.5 Stages of Pelletizing

Chapter 2: Literature Review 14 – 20
2.1 Mechanism Of Green Ball Formation
2.2 Drop Number
2.3 Parameters affecting reduction behaviour of pellets
2.4 Swelling of Pellets during Reduction

Chapter 3: Experimental Procedure 21 – 25
3.1 Sample Preparation:
3.1.1 For Green Strength Measurement
3.1.2 For Study of Reduction
3.2 Testing:
3.2.1 Green Strength Measurement: Drop Number
4
3.2.2 Reduction Behaviour: Swelling and Percentage
Reduction

Chapter 4: Results 26 – 39
4.1 Results: Drop Test
4.2 Results: Percentage Reduction
4.3 Results: Swelling

5.1 Chapter 5: Conclusion 40 – 41

References 42

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LIST OF TABLES
Sl. No. Name of Table Page
Table 4.1 Drop number of samples for green strength
measurement
Table 4.2 Weight loss upon Reduction of Pellets of 13% water
content
Table 4.3 Weight loss upon Reduction of Pellets of 15% water
content
Table 4.4 Increase in diameter upon reduction for 13% water
content
Table 4.5 Increase in diameter upon reduction for 15% water
content

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LIST OF FIGURES:
Sl. No. Name of Figure Page
Fig. 2.1 Influence of water addition on green ball formation
Fig. 2.2 Influence of capillary forces on bonding mechanisms
Fig. 2.3 Alternatives for green pellet formation
Fig.4.1 Sample of 15% Water Content, 90% 350 mesh size pellet
Fig. 4.2 Drop Number vs. Water Content for 100% 350 mesh size
Fig. 4.3 Drop Number vs. Water Content for 90% 350 mesh size
Fig. 4.4 Drop Number vs. Water Content for 80% 350 mesh size
Fig. 4.5 Drop Number vs. Water Content for 70% 350 mesh size
Fig.4.6 Drop Number vs. % 350 mesh size
Fig.4.7 Percentage Reduction vs. % of 350 mesh size
Fig.4.8 %increase in diameter vs. % of 350 mesh size

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CHAPTER – I
INTRODUCTION

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1.1 Introduction to Pelletizing
India is one of the leading producers of steel, currently ranked 4th in the world
with a production of 76.7 mtpa. Annual production of steel In India is expected
to reach close to 200 million tonnes mark by the year 2020 making India
world’s second largest steel producer. India has about 28.5 billion tonnes of Iron
ore reserves. However, almost 60% of the ore that is mined is in the form of
fines of low iron content. These iron ore fines cannot be directly used in the
blast furnace as they pose the following threats:
1. Iron ore fines severely reduced the permeability of the bed, jeopardizing
the reduction reaction in the blast furnace
2. The fines leave the blast furnace in combination with the flue (top) gas,
bringing down the efficiency of the furnace.
With the projected steel production, requirement of iron ore is expected to be
around 350 to 400 million tonnes per year. This makes it imperial for the steel
industry in the country, and even worldwide, to utilize the iron ore fines.
Agglomeration processes are used for this purpose. The major agglomeration
processes for iron ore fines are pelletisation and sintering. The two processes
complement each other as they utilise fines of different size ranges. Other
lesser-known agglomeration processes include stamping, briquetting, etc.
However, these processes have more or less been outdated due to the low
efficiency and lack of economic viability.
With the fast-growing pellet industry and increasing use of iron ore pellets in
the charge for ironmaking, pelletisation of iron ore fines has turned out to be an
important area of metallurgical studies. Pellets now form a substantial part of
the charge in blast furnaces and may be as high as 30% in some cases. It has
already been used in secondary ironmaking processes with 100% pellet
charging. Countries like South Korea and Japan have successfully reported
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