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The Big Picture of Iron Ore Flotation:
Optimizing the Whole Process
S.K. Kawatra, V. Claremboux
Michigan Technological University
ABSTRACT: Recent optimizations in iron ore processing consistently require looking at the big picture of
the whole process. This paper presents several case studies identifying optimizations crossing unit operation
boundaries and how optimizing flotation influences the rest of the plant. Carefully controlling magnesium
and calcium ions throughout the process can lead to significant improvements in flotation, filtration rates,
pellet quality, and dust control. Similarly, other potent surface active reagents originally identified for flotation
can improve pellet quality and grinding efficiency. In each case, applying flotation knowledge in other unit
operations leads to insights into the big picture of optimizing the whole process.
INTRODUCTION
Iron and steel are used all throughout modern industry and
everyday life, as one of the most cost-effective high-strength
structural materials. Several interlocked steps are involved
in the process of transforming iron ore mined from the
ground into useful forms such as metallic iron or one of
many types of steel. Raw iron ore contains one or more of
a variety of gangue materials, with the most common being
minerals such as silica, alumina, kaolinite, or apatite. Each
of these gangues is detrimental to refining processes and for
low grade iron ores it is critical to remove as much of these
impurities as possible at minimal cost. For many iron ore
bodies, flotation is chosen as the most effective and eco-
nomical way approach for rejecting gangue materials and
producing a high grade iron concentrate.
An archetypical example of an iron ore flotation pro-
cess is shown in Figure 1, including comminution, des-
liming, flotation, and filtering. These four sections are a
traditional division of the major unit operations, and tre-
mendous effort has been spent on each of these sections by
industry and academics alike to ensure their performance
is optimized.
The end goal of this process is essentially always to cre-
ate an iron concentrate agglomerate, such as pellets, with
acceptable iron grade and material properties, plus any nec-
essary additives, at as high of iron recovery as possible. Each
step of the process must perform well for the overall process
to be successful, so naturally attempts to improve the over-
all process often start by looking at each step of the process
and making improvements.
It is often the case that these distinct sections are
considered in isolation. Improvements in crushing and
grinding are often targeted at very worthwhile goals such
achieving liberation more effectively and reducing energy
costs or avoiding overprocessing of material. Improvements
in flotation are often targeted at very worthwhile goals such
as improving flotation recovery, improving gangue rejec-
tion, increasing flotation capacity, or reducing reagent con-
sumption without sacrificing production.
However, each of these changes has implications for
downstream processing. When grinding aids are used in
The Big Picture of Iron Ore Flotation:
Optimizing the Whole Process
S.K. Kawatra, V. Claremboux
Michigan Technological University
ABSTRACT: Recent optimizations in iron ore processing consistently require looking at the big picture of
the whole process. This paper presents several case studies identifying optimizations crossing unit operation
boundaries and how optimizing flotation influences the rest of the plant. Carefully controlling magnesium
and calcium ions throughout the process can lead to significant improvements in flotation, filtration rates,
pellet quality, and dust control. Similarly, other potent surface active reagents originally identified for flotation
can improve pellet quality and grinding efficiency. In each case, applying flotation knowledge in other unit
operations leads to insights into the big picture of optimizing the whole process.
INTRODUCTION
Iron and steel are used all throughout modern industry and
everyday life, as one of the most cost-effective high-strength
structural materials. Several interlocked steps are involved
in the process of transforming iron ore mined from the
ground into useful forms such as metallic iron or one of
many types of steel. Raw iron ore contains one or more of
a variety of gangue materials, with the most common being
minerals such as silica, alumina, kaolinite, or apatite. Each
of these gangues is detrimental to refining processes and for
low grade iron ores it is critical to remove as much of these
impurities as possible at minimal cost. For many iron ore
bodies, flotation is chosen as the most effective and eco-
nomical way approach for rejecting gangue materials and
producing a high grade iron concentrate.
An archetypical example of an iron ore flotation pro-
cess is shown in Figure 1, including comminution, des-
liming, flotation, and filtering. These four sections are a
traditional division of the major unit operations, and tre-
mendous effort has been spent on each of these sections by
industry and academics alike to ensure their performance
is optimized.
The end goal of this process is essentially always to cre-
ate an iron concentrate agglomerate, such as pellets, with
acceptable iron grade and material properties, plus any nec-
essary additives, at as high of iron recovery as possible. Each
step of the process must perform well for the overall process
to be successful, so naturally attempts to improve the over-
all process often start by looking at each step of the process
and making improvements.
It is often the case that these distinct sections are
considered in isolation. Improvements in crushing and
grinding are often targeted at very worthwhile goals such
achieving liberation more effectively and reducing energy
costs or avoiding overprocessing of material. Improvements
in flotation are often targeted at very worthwhile goals such
as improving flotation recovery, improving gangue rejec-
tion, increasing flotation capacity, or reducing reagent con-
sumption without sacrificing production.
However, each of these changes has implications for
downstream processing. When grinding aids are used in