Friends, in the previous lecture I have talked
about the Sources of metals and we have seen,
that we can get metals in the form of minerals
and ores, from land mass and they distributed
all over the earth crust. We can get metals
from the sea, not only sea water but marine
organisms, manganese nodules in the sea floor.
And we have seen that, another source of metals
is metallurgical waste or metal scrap, because
from them also we can get extract metals,
and we call them secondary metals. Now, we
today we concentrate on getting metallic values
from ores and minerals available in land masses,in
land deposits.
Now, very rarely, these days we find that
there are mineral particles on the surface
ready for a extraction process;may be there
was a time when there were bolders of ores
or minerals, which were suitable for an extraction
process by our ancients, but now a days we
need some kind of a dressing of the ores to
prepare them for subsequent extraction processes.
So, the two words which are used, they both
mean the same, one is mineral beneficiation
and the other is mineral dressing. All the
people prefer different terminologies and
essentially, mineral beneficiation and mineral
dressing can be defined as processingraw materials,
that is the ore to yieldmarketable products
that you have mined some ore from somewhere,
but no industry would like to buy because,
they would like to have something in a better
form. Something that can be readily used in
the industry, so what you have to supply to
an industry, that is in the extraction business
is a marketable product and that means, that
having taken the ore out of a mine we have
to dress it up, we have to do something to
it to make it more acceptable to the industry.
In mineral beneficiation, this is done by
by means that do not destroythe physical and
chemical identity 
of minerals.This means, we do a lot of things,
to that ore that we have got, but we do not
change the chemical identity, and all we can
do is what we call unit processes and unit
operations rather.
Unit operations are for dressing up ores without
changing the physical and chemical identity.Say
for example, you have an ore which has a lot
of unwanted materials, gangue materials, as
I said sand and aluminosilicates that you
really do not want to go into the processes.
Suppose, we havea method of taking them out,
you have not done anything with the minerals,
the mineral stayed as such. Suppose, the particles
are too big, you crush them and ground them
and you make them finer, you have not changed
the chemical or physical identity, these are
called unit operations. And mineral beneficiation
techniques essentially mean such operations,
where you are making it more acceptable to
the industry, but you are not changing the
basic nature, chemical or physical nature.
However, the technologies have now change
the great deal, and there are occasional exceptions
to this, say if an iron ore which is or some
other mineral, which has an component f e
o, we can do magnetizing roasting; it means,
heat it up slightly in oxidizing atmosphere
make it f e 3 o 4 and you remove it by magnetic
treatment.
This is not a unit operation, it becomes unit
process because, you are playing with the
chemical nature of a mineral, but sometime
this is accepted within the scope of unit
operations in mineral beneficiation, there
also some situations, where we take out a
mineral value by chloridizing it and it comes
out as a vapour, as a gas or as a liquid and
we have to separate themetallic value by chloridizing
that and we include that in mineral beneficiation,
but generally it is the physical operations
or unit operations which come under the definition
of mineral beneficiation.
Now, in the most common operation in mineral
beneficiation is crushing and grinding using
various equipments.Now,I am showing some very
basic equipment like, you have big particles
of ore, you feed them into a device where
this is banging against it all the time to
very hard surfaces, very often these are tungsten
alloys,so gradually it gets broken into smaller
pieces and you get finer particles coming
out.There can be other kinds of devices like
this again, the ore is ((cruise)) through
smaller and smaller openings comes out, and
here there is something which is rotating
all the time, so the breakage is much more
efficient.This is another device, there ore
comes into the peripheries, thus thus though
enter into this passage, whole thing is of
course is rotating as you see here and the
ore comes out as in finer form.
There also these are called mills, the ore
coming here there is something rotating all
the time and its ore particles gets ((cruised))
between two hard surfaces and this, they are
hit by this hammers, here is another one ore
comes and comes out becomes much particle
size drops. Now, this sort of operation, the
technical name for this is comminution, we
call it crushing and grinding, but comminution
is a more technical term, which isactually
a unit operation for size reduction.
Now obviously, this operation requires a good
amount of energy, and an estimate is, you
need 5 kilo watt hour per ton to 25 kilo watt
hour per ton depending on the kind of equipment
you are using or how hard or how brittle the
ore particles are. Very often, comminution
is the first step in mineral processing, because
it achieves several things, not only or the
particle size reduced, but you create new
surfaces and you liberate minerals.
Now, what do you mean by the word liberation
of minerals? To understand that, you must
understand what normally is an ore particle
like, a particle of ore or rather a mass of
ore would comprise of agglomerates of various
mineral particles, different kinds of mineral
particles are agglomerated and it has happened
in nature over millennia and they form a mass
in which, there are different minerals, there
also gangue materials, they have been all
((cruise)) together.
Now, we want to treat the mineral values by
some processes to extract metal, one metal
or more metals, so we need to liberate it
from the from each other, and from the gangue
materials and this is very effectively done,
if you break things up. We say that, when
you have single mineral, single mineral particles
together, agglomerated together we call them
free particles, and when there are different
minerals together in an aggregate, we call
them locked particles.
So, essentially by size reductionwe try to
unlock the thethe minerals and of course,
we can or we can always talk about degree
of locking or degree of liberation, the more
liberated they are, the more free air particles
or more single mineral should be available
in the mass.
The the definition of degree of liberation
is, the percentage of mineral or phase occurring
as free particles in relation to the total
of that mineral occurring free or locked forms.And
conversely, the degree of locking of a mineral
is the percentage occurring as locked particles
in relation to the total occurring in free
and locked forms.Now, we need not go into
these details, essentially you get the idea
that we have to breakto free the mineral particles,
one kind of form from the other kinds of things.
Now, when we reduce the size, then this happens
quite automatically.
Now, here is a schematic representation of
a of a mass of ore, where there are different
kinds of minerals locked up, and this is one
kind of mineral, this is another kind of mineral,
the white one,and this is the hatched one.
And when size reduction takes place, and this
is broken, may belines of fracture could be
here, the lines of fracture could be here
and very often the lines of fracture go along
the inter granular boundaries, by grain you
mean one kind of particle, a mineral particle
this is one grain, this is another grain,
which is another mineral particle.
So, very often, it will crack along these
lines and they will get liberate. Now, sometimes
there can be this kind of fracture also, means
not only it will go along the boundaries of
different grains, but across a particular
mineral that can also break, but no matter
what happens.One thing is sure, if you break
the the aggregate into smaller sizes, you
liberate more of the minerals from one another
or from the gangue, this will happen even
if the cracks are along the grain boundaries
or even if it goes through some grains it
does not matter, we need this.
So, when you have reduce the size withcommunition,
thenyou are creating much larger surface area
and this will be advantages in processes,
where we need larger surface area like if
you want to go for leaching and dissolution
in a in a acid or in an alkali, the larger
the surface area, the better will be the rate
of dissolution. So, not only we are creating
larger surface area by breaking the particles,
we create new surfaces areas, new surfaces
which may be more active than the old surfaces,
because they have not been ((whether)) they
are fresh, they are ready to react with environment.
So, the communition achieves many things,
it achieves liberation of grains, means one
kind of particles from the other kind of particles
gets liberated from the ganguegangue material,
unwanted material by using the size we create
larger surface area, we also create new surfaces
which are more active.
There are some processes, wherewe might like
to have larger particles like at one time,
the blast furnace operation required fairly
large particles, because in the blast furnace
you need to have porosity, but today the tendencies
not to have natural particles, we actually
take finer material make sinters out of them,
sinters are again larger particles we create
the the porosity in the bed, very few processes
today would like to have large particles,
most of them would operate on fine particles.Of
course, the the degree of finest, that we
need will depend on the processes we operate.
If you have a fluidized bed processing in
a fluidized bed, where you have the particles
or fluidized by a gas coming from the bottom
screen. Obviously, they have to be fine smaller
particles, because then they are easily fluidized,
but then if they are too fine, then they will
fly off.
So, there is there is a size limitation, there
should be fine, but not too fine. In mineral
beneficiation techniques like floatation,
we want finer particles, we want large surfaces,
which will attach the particles,will attach
to soap bubbles and float down.So, unless
the particles are very fine,this soap bubbles
will not able to carry them up, it is like
when you do washing with soap, the dirt comes
out with the soap bubbles, butyou know if
they had been large particles floatation will
not work.
So, we need finer particles in many processes
as I said, if there are surface properties
involved the surface is coming to picture,
finer particles are lighter in weight, they
are purer in terms of the mineral value. So,
the crushing and grinding would be one of
the first steps that we need. Crushing and
grinding also has to be followed by a process
called sizing, you simply cannot undergo comminution,
crush, grind or leave it at that.
You have to define to what degree you have
reduced the size, and for that we need screening.
Now, you may have seen, the way the house
wife you know screens an atta, they have a
circular device of perforated base and they
will put the atta, and if when they do that
the finer things goes and the coarser things
stay on the top and they rejected.
Something similar is done for the industry
also, that we have a perforated base, see
this could be say about diameter about 200
millimeter and about 50 millimeter high, very
usually in the laboratories they are made
of brassand in this there are screens and
they have standard openings. So, if we do
this sort of thing, then the finer particles
go through and coarser particles are remained
on down, but this is what we what we do in
the laboratory in small scale, in the industry
this will not happen,what we can do? We can
have a we can have astack of such screens,
the the coarser ones will be on the top, the
finer ones will be at the bottom.
See, if there is a series of screens like
that, and they are vibrated in a stack, so
the finer and finer particles keep going towards
finer and finer screens, and the coarser ones
on top.So, we have now, we do a size classification
that between this size to this size in this
screen, this size to this size in that screen
etcetera, etcetera.
We have to have the size reduction within
certain limits because, industrial processes
define that, we do notwant the input materials
to be in this size range; now in the industry
of course, they do not wantthis vibrating
screens like that.
There are other processes like for example,
they may have an incline with rods at certain
spacing and the ore goes above them, the whole
thing is vibrated, that the finer the openings
between the rods will go down, and the coarser
works will be on top.There could be a series
of such things, so in the process there is
also similar and other methods, this parallel
rod device is called the greasily, these greasilies
are used for size reduction, there are also
other other devices. So, essentially we always
want the input material in an industrial process
of a particular size and that is done by mineral
beneficiation technique, a comminution.
To give you an example, why, what happens
in a size reduction,here is a simple to give
you an idea as to what we mean by size reduction.
This is a typical size ranges for various
materials, it is in angstrom unit.
You know that, we mean by 1 angstrom is 10
to the power minus 4 micrometer, that is 10
to the power minus 7 millimeter, that is 10
to the power minus 8 centimeter, and you get
an idea here, that the fine silt would be
here, the river gravel means the smaller particles
are here, beach sand is here, this is a log
scale. Now very often, we will be actually
operate in in this kind of range in most of
the industrial processes, 200 mesh, mesh is
a unit defined in most book say that, what
is a mesh? 10mesh is about 2 millimeters,
200 mesh is about 0.075 millimeter and they
they are many standard conversion things are
available,so in most of the industrial processes
will operate in this range.
To give you a simple example, why we need
to do this kind of sizing? Say, here is the
schematicdiagram of an electrostatic separator,
which can be used for electrically conducting
mineral particles. Suppose, we have an ore
body in which there are particles of minerals,
which are electrically conducting and others
are not electrically conducting. Now, as such
if you let that go under an electric field,everything
will pass through, there will be no separation,
but if you do comminution, if you reduce the
size, if you have liberated the electrically
conducting particles from other kinds of things.
Then, we can use a device like this, while
the feed will come on a belt, conveyer belt
and these are the particles of ore, where
all kinds of grains, all kinds of minerals
with different electrical conductivity properties
and we will have a separation here. Because,
those that are electrically conducting will
fly off, because this is the rotating drum
that will attract, so nonconducting will go
in some places, electrically conducting particles
will go in another places, so we can have
a separation based on electrostatic charges.
Now, all processes of mineral beneficiation
exploit one or more properties of ore particles,
and here is a list of unit operations to indicate,
what is being exploited where? what I describe
this as,comminution or size reduction, obviously
exploit the property of brittleness because,
the the ore particles are brittle brittle
does not mean that any force will break it,
but some force or other will break it, some
need more force and some need less force but
they are brittle, in the sense that it will
not get deformed.
So, we have the grain aggregates of different
particles, they will break into smaller fraction,so
we are exploiting the property of brittleness,
then we are doing sizing; we showing to screening
using various devices, so there is greasily
or other things and we are creating different
fractions, we are exploiting size difference
amongest particles.
This can be done in various ways; in the earlier
days, it is to be done by handpicking, and
handpicking was also get quiteadvanced and
it is still done in some places, that on a
conveyer belt whatever has been mind is going
and there are skilled labours, labours on
both sides.Men and women will pickup particles
of a certain size they have been trained to
do that and coarser particles in one side,
finer particles in one side, they can also
do something more, they can be trained to
pickup particles rich in certain kind of minerals
that can also be done,this is called handpicking,
but then big industries handpicking will no
longer do.
Then there are hydraulic classifications,
there are many many kinds of devices and I
will not go into that, mineral beneficiation
techniques comprise a full course in many
undergraduate curriculums. Then there is concentration
using a pulp,we will discuss an example of
this in detail. Sizing by hydraulic classification
means, that you have devices where it can
be air or it can be fluid and the entire body
of ore issentinel and the whole thing circulate
like this, and there is a separation between
some which go up and some particle which sink
they all are make use of the properties or
size in density differences.Now, the concentration
using a pulp is a very important method of
separating different kinds of minerals, by
a pulp we mean the solids that have been quest
and ground and then its its mixed with water,
so we have solids say 10 percent, 15 percent,
20 percent solids in water, it is called a
pulp; it it can be agitated, it can be made
to flow, so we will say a pulp is flowing.
Now, when we have a pulp, there are many devices
that can be used to separate different minerals
from one another, exploiting the properties
of size, density and shape. Size, density
and shape, all defined the way particles move
in a pulp and I will give an example that
will perhaps make things more clear. Then
there are magnetic separation devices, which
make use of magnetic permeability and susceptibility,
so if if you have in an ore, lot of mineral
particles which have been liberated and if
that are magnetic minerals, using magnetic
devices we can separate them from the nonmagnetic
ones.
In fact, we will come to some examples, wherethere
can be a series of minerals of gradually changing
magnetic property they can be separated using
magnetic separation, same as with electrostatic
separation I give you an example. And floatation
is very important for sulphides because, the
sulphide particles attach themselves to soap
bubbles and so if you have a finer finely
ground sulphide particles, they can be separated
from the gangue simply by the floatation technique.
And we will see that in the case of some sulphides
like, copper sulphide, the ore may contain
only 1 percent copper sulphide.
But, after crushing and grinding if they are
sent through floatation device, we get a concentrate
on the surface which is about 25 to 30 percent
copper sulphide, the gangue materials do not
float, they sink at the bottom, butthe sulphur
come to the top. There also other methods
like coagulation, adsorption, filtration,
drying, agglomeration, etcetera, etcetera.We
are not going to discuss these things, becausethere
will be other times we will see that.
Let me discuss here one example, which actually
is very relevant for indeed, it is the beneficiation
of beach sands, what do we mean by beach sands?
I do not have it here,but it is here, in a
coastal area of India there are certain areas
all along our southern course way up to the
also eastern course, our eastern side whether
in some some areas with the sand is actually
almost black, and it is black because it containsilmenite,
ilmenite some of you know is written as F
e o T i o 2 or F e T i o 3 is the source of
titanium.
Now, in the beach sands in the Tamilnadu coast,
this is an analysis given in one source,it
may contain from 8 to 52 percent ilmenite,
zircon 0.87 to 10,sillimanite, rutile is T
i o 2, then garnet, silica, monazite this
is important,this is important because it
is a source of thorium and rare earths and
there are some others.
In a Kerala beaches also you find some beach
sands containing as high as 80 percent ilmenite,
there is also zircons, sillimanite, rutile,
garnet and monazite. There are beach sands
of Orissa also, which they contain all these
things. Now, these are all very valuable minerals,
from ilmenite we getnot only titanium, we
also produce T i o 2 which goes into the paint
industry.T i o 2 is very white, from zircon
weget zirconium, and from monazite we get
thorium, rare earths and many other elements.
Actually its very interesting that, there
is an interesting theory as to why the olive
ridley turtles come for to deposit their eggs
in certain area in Orissa called Gahirmatha,
you may have heard about Gahirmatha around
the month of February thousands of turtles
come to to lay their eggs in the beaches and
which hatch and then and the hatchlings will
going to the sea.
One of the reason they say why the olive ridley
turtles come to Gahirmatha is because, we
have the beach sand with ilmenite very dark,
they observe sun’s rise and they are very
worm,so the thethe sand bed beach sand bed
is very wormed there just just right for the
turtles they have found the spot, where the
eggs will hatch because they drop their eggs
they cover them and they go away into the
sea.
Anyway, what I am trying to say is,we have
a very valuable resource in beach sandsin
many locations along our course line from
Gujarat, Tamilnadu, Kerala and this is a very
valuable mineralthat needs to be processed
to extract different minerals out of that,
and the different compounds and different
metals.
How do you treat a complex mixture like this?The
treatment of such ore bodies, which have so
many different kinds of minerals, all with
different properties has actually have evolved
over hundreds of years, may be thousands of
years, and people have found different ways
of doing things by trial and error.
And now onlythe science is trying to understand,
exactly how these things work?There are similar
techniques in our household things alsolike,
if you have you may have seen our housewife,
if when they take, there is a there is a dirt
in the wheat, they have a pan they keep doing
that and they keep blowing that, so the lighter
ones, the dust particles and theand their
coverings they they flown, they fly away and
they get something; this is a kind of technique
is also adopted in in the mineral industry.
Now, I use to be fascinated by the techniques
that are adopted in the in the mineral industries
and I worked in regional research laboratory
in Bhubaneswar, very near that there is Indian
rare earths, which process beach sands primarily
for production of T i o 2, and also to get
the other fractions like, monazite, garnet,
sillimanite, etcetera, which will go into
other industries.
Now, then in a in a place like that, there
are whole a series of mineral beneficiation
techniques are adopted, unit operations, electrostatic
separation, magnetic separators, etcetera,
etcetera, etcetera. I will describe only one
operator, which is called the spiral, which
is ever useful equipment for separation of
different minerals based on size, density
and shape. Now, if you see the principle of
one, you will see how similar principles have
been employed elsewhere.
Now, in the beach sands I have just described,
there are actually some minerals we call very
heavy minerals; this very heavy minerals means
ilmenite, zircon, and monazite these are very
heavy minerals.Then we have heavy minerals,this
is not o this is bracket closed, heavy minerals
which are garnet and sillimanite, and then
we have lighter minerals like silica, this
may be around 2,this will go up to 7, 8, 9,
10 that kind of density.
Now, we want to find ways of not only separating
very heavy minerals and heavy minerals from
lighter minerals, but again VHM from HM, and
then also ilmenite from rutile, zircon and
monazite, we want to get different fractions.
Now, this device that I am going to describe
called spiral concentrator, achieves this
remarkable well.
.
Now, first of all, let us see what is a spiral
concentrator,this is called a single start
spiral.The total height would be say something
like 3 meters or 4 meters may be little more,
see as I as many halls.
A single start means one spiral, there can
be multiple start spirals, which mean that
at one place, you have more than one spiral,
like this spiral is going to occupy say, as
a diameter about say 6 feet or 2 meters, so
if you want another spiral there has to be
another space than another space, but people
have found that, they will put one more spiral
in between these spaces to go through that,
then there will be another one through so.
There are there are spirals with three starts,three
spirals are at one place, forget about that,
look at just one spiral.The idea here is,
that a slurry which meanscertain amount of
solids particles above in in water will be
pumped from the top and it will flow through
this vessel, so it will go round and round
and round and round and come out at the bottom.
When that is happening if you see, it is a
trough which goes with a slope downwards.
How will the water flow in water?We will have
0 velocity in contact with the perimeter,
it will have a 0 velocity at the center, so
there is a velocity gradient from the center
to the side at any place,at any place here
from center to the perimeter, there is a velocity
gradient.
Now, the water will be flowing at a much higher
velocity towards the perimeter, it will be
it will be, it will slow down towards the
center and we saythat in the perimeter, in
the outer most area mostly water with fine
particles will flow, because trapped by the
high velocity of water, water is flowing pretty
high velocity all the fine particles will
go at this side.
As you go we go inward towards the center,
there is a small area wherethe water velocity
is maximum, because as I mentioned at the
perimeter it is 0, velocity is also 0 and
the center, somewhere in the center the velocity
is maximum and when it is flowing so fast,
not much separation of minerals take place.But,
as we come closer to the center, the inner
regions most active when velocity begins to
slow down, why is begins to slow down?Because
of friction, drag and heavier mineral begin
to separate;look at this diagram, which is
little more makes it little clearer.
The slurry is going through this device, flowing
through this device and at every stage, from
the outer sections we are tapping out some
water, we are tapping out some water from
the middle part from the middle part and we
will we will take out something from the central
part. Now, this is the cross section of of
one place here,now you see not only there
is a gradiate in water velocity as you go
from this center to the side, there will be
gradiate in water velocity in the vertical
direction also. Because, the heavier particles
are beginning to come towards the center,
so the water will find it difficult to go
through, so there are all kinds of things
happening in this device.
Someone substances very light particles will
fly towards the periphery, they will get separated
and the heavier minerals depending on not
only the density by size also begin to aggregate
towards the center, but there are also fractionation
amongest them and there are there are devices
to tap them from different places.
So that, at the end we get three products,
one the lighter products are the periphery
are taken out, the heavy minerals will come
at the bottom, in between we will have the
middlings.This kind of device separates the
minerals and the separation will depend on
a large number of factors, but again go through
what is happening there, outer most mostly
water with fine particles tapped by high velocity
water means, silica we will get eliminated.
Then, where there is maximum water velocity
not match is happening,it is only the inner
regions where the they will get minerals are
begin to separate depending on their density
and size.
How do you study this?Now, some of my friends
and I looked at only one spiral, where they
were trying to separate these minerals, and
they have add operation going on for some
20 years because, there is lot of trial and
error involved in knowing how you separate
the minerals and the general wisdom said that,
there are three factors which are mostly important.
And these are what we say, first of all through
put, how much you are sending through the
spiral per hour and the other is the concentration
of the particular mineral in the mass in the
mass of minerals, and the third one is the
pulp density.
What is the fraction of solids in the water?There
are some other things we do not know, we we
need not consider. I i do not know whether
I am I am I am able to make it clear, but
we have a device, which is going to separate
the minerals depending on their density and
the operators find through their trial and
error, that they have to control three factors.
As to how much they pore from the top per
hour, becauseif you put too much, too fast
separation is not effective, if you send too
little of that the slurry, separation not
too effective, you need to have a certain
concentration of the solids in in water, if
it is too high it does not work very well,
it is too low does not work very well.And
also it depends on how much of a particular
mineral do you have in the input mass for
it to be recovered effectively. Now, we have
looked at their data and there are some statistical
techniques, which is called statistical design
of experiments.
We developed an equation like this, that in
the product we said first of all, let us consider
the entire hot metal, several minerals at
a time, amount in the concentrate depend on
tons per hour. What is the feed rate?It will
depend on percentage solid; it will depend
on percentage hot metal in the feed and so
on and so forth.So, we were able to quantitatively
develop an equation that, if we want 3 or
4 heavy metals together the total yield will
be defined by these parameters like this,
tons per hour, feed rate, percentage solid
and also the how much of that heavy metals
is in their total world.
Subsequently, we have done it for every single
mineral and such equations have been developed,
so an operation which was basically developed
by trial and error, we try to put science
into it looking at their own data; their own
data over say 10 years, 5 years, we picked
up certain selected some data,develop some
equations and when you have an equation like
that, which expresses the yield of the total
heavy metals or yield of a particular mineral
in terms of factors like, the tonnagethat
you are sending through a percentage of total
solid, percentage of metal or hot metal in
the mass you can develop an equation.
Once you have an equation, you can go through
an optimization technique to maximize that,
under what conditions of throughput solid
concentration and hot metal in feed of the
particular metal in feed you get the maximum
yield, we have done that, and computers do
that if you feed right kind of data.
And we had this kind of information,we have
found equations for heavy metals, heavy minerals,
very heavy minerals, and then individually
for ilmenite, garnet, monazite, rutile, zircon,
sillimanite, everything has been done, so
the beauty now is that, we found what will
be the optimum conditions.That we found mathematically,
and these are the once we predicted, that
under this kind of conditions this is what
will happen and their 15 or 20 years experience
they said, these are the kind of data they
had; and it was very interesting what they
have done over 15 to 20 years, you can do
that in two months if you pick up the right
kind of data, and then you say these are the
optimum conditions forgetting maximum yield
of this mineral.
Well, this can be done put in terms of the
computer camera also, print that for heavy
metal in this case, it is heavy heavy mineral,
it can be for very heavy minerals all together
or single minerals, we can plot them heavy
mineral in the concentrate as a function of
percentage solid and tonnage per hour, we
did something like that for very heavy minerals
also.
And then the computer gives a software also,
that for any particular concentration, if
you want this much of concentration in the
product, you have to, you can cut it through
this, you can get a horizontal thing surface,
that for different concentrations of very
heavy mineral, 42, 44, 46, 48, 50 these are
there are different combinations of solids
and tonnage per hour will give you that.
I will stop it here now, and I will simply
say that I amsorry I do not want to go into
the details of this topic, but mineral beneficiation
technique is actually it depends very heavily
on trial and error over centuries.
And now this equipment have been standardized,
but we can play around with this equipment
to do lot of scientific research, bringing
lot of science, lot of mathematics and gives
them optimization techniques which will minimize
the labour that they have to put into find
what are the best conditions. So to summarize,
mineral beneficiation means mineral dressing
and there effort to unit operations, which
will make an ore body more suitable for an
industrial extraction process and all unit
operations exploit certain property of the
minerals.
To start with communition, which is size reduction,
it will make use of their brittleness and
there are other properties. Rarely would a
unit operation change the physical and chemical
nature of minerals, but there can be some
exceptions as I have mentioned.
I will not discuss this subject anymore, but
everywhere subsequently, whenever you talk
about an extraction process, you will see
there will be a reference to someone or more
mineral beneficiation technique, and if necessary
I will give you little more detail. I have
givea I have a particular example of use of
a spiral, if you are interested you can you
can read that of in internet or in any book,
thank you very much.
