Title of Invention

"A NOVEL PROCESS FOR PREPARATION OF SELECTIVE AND POWERFUL MIXED FROTHER FOR COAL FLOATATION

Abstract The present invention is provided with a process for preparation of a selective and powerful mixed frother for Coal flotation through blending mechanism of prime single frothing molecules comprising a two phase (air-water interface) floatation characterized parameter comprising a surface activity, a dynamic floatation index, a critical coalescence concentration and bubble size at ccc; a three phase (air-water solid interface) floatation characterized parameter comprising a selectivity, kinetics, size wise floatation performance; blending of pure single frothing molecules in the presence of a mixed chemical system of methyl isobutyl carbinol (MIBC) and polyglycol ether PPG-1000.
Full Text FIELD OF APPLICATION
The present invention relates to a process for preparation of a selective and
powerful mixed frother for coal floatation. In particular, it relates to a process
for screening frothing molecules for coal floatation under scientific guidelines, for
coal benefication.
BACKGROUND OF THE INVENTION
The separation of fine particles of coal contained in coal slurry through the use of
froth floatation processes is well known. Froth floatation processes involve
introducing air into the coal slurry. The hydrophobic particles of coal are
contacted with finely disseminated air bubbles such that the fine air bubbles
become adhered to the hydrophobic coal particles. The particles carrying
bubbles are then permitted to rise, forming froth on the surface of the slurry.
The froth, containing the hydrophobic particles of coal, is skimmed from the
surface of the coal slurry and collected, while rejecting any hydrophilic particles
of impurities which do not adhere to the air bubbles and which remain
suspended in the slurry.

Floatation of coal fines has become Increasingly important as a separation and
cleaning process where there is a lowering in both the particle size and grade of
the coal being recovered from mining operations. The ability to remove the coal
fines from coal washery or tailings is also advantageous in order to recover coal
fines missed by other techniques of coal recovery.
In order to improve the selectivity and recovery of the floatation process and
enhance floating of the coal fines, various types of reagent have been developed
for addition to the slurry. Frothers and collectors are two types of reagents
which are commonly used in coal floatation.
Floatation frothers are used to facilitate air dispersion into fine bubbles, and to
stabilize the froth, According to Leja-Schulman's penetration theory frothers
accumulate preferentially at the air-water interface and interact with collector
molecules, adsorbed onto solid particles in the particle-to-bubble collision and
attachment Effect of frothers on bubble size results from their ability to prevent
bubble coalescence. The degree of bubble coalescence decreases with
increasing frother concentration and at a particular concentration known as
critical coalescence concentration (COC) for a frother, it reaches non coalescence
environment Above the critical coalescence concentration there is very little
effect on bubble size and to a large extent, the cell geometry affects the bubble
size distribution.

A successful frother must allow sufficient thinning of the liquid film between the
colliding bubble and the particle so that attachment can take place in the time
frame of the collision. Thinner liquid film enhances the bubble-particle
attachment during collision process but it also increases the bubble-bubble
coalescence. Thus a successful frother must achieve a delicate balance between
these two competing processes and provide sufficient stability of the
bubble/particles moiety and yet allow the weakly adhering or mechanically
trapped particles of unwanted materials to escape with the draining liquid.
Gravity is the main driving force for the drainage in froth phase. The surface
gradient along the air-water interface creates the Gibbs-Marangoni effect that
acts to retain the film thickness and prevent bubble coalescence. The froth
stability also depends on, (a) particle size (finer particles stabilize froth), (b)
wetting characteristics (particles having contact angle less than 90 degree
stabilize froth and (c) shape of particles.
Neutral frothers can be essentially divided into four groups. The first group
consists of aromatic alcohols such as a-creasol and 2,3-xylenol. A second group
is the alkoxy types such as triethoxy butane (TEB). The third group consists of
aliphatic alcohols such as 2-ethyl hexanol, diacetone and methyl isobutyl carbinol
(MIBC). In recent years, a fourth group of synthetic frothers consisting of

polyethylene oxide (PEO), polypropylene oxide (PPO) and polybutylene oxide
(PBO) types have been introduced into the market These chemicals may be
presented by the general equation:

It is generally known in industry that it is difficult to use a single pure frother
that will effectively give good overall floatation performance for wide size
distributed floatation feed (0.5 X 0.0 mm). It is due to some frothers are
effective for coarse particles and others are good for floating ultra fine fractions.
Attempts have been made to develop blended frothers for floating wide size
distributed floatation feed. Examples of patents directed at improved frothers
include U.S. Patent No. 4,582,596 issued April 15,1986, U.S. Patent No. 4,915,
825 issued April 10, 1990, U.S. Patent No. 4, 272, 364 issued June 09, 1981,
U.S. Patent No. 4, 504, 385 issued March 12,1985, U.S. Patent No. 5, 304, 317
issued April 19,1994, U.S. Patent No. 3,710,939 issued January 16,1973, U.S.
Patent No. 4, 606, 818 Issued August 19, 1986, U.S. Patent No. 4, 761, 223
issued August 02,1988, U.S. Patent No. 4,925,559 issued May 15,1990.

In general practice, the frothers are screened under the general guidelines
(price, availability, solubility in water, environment impact etc) and verification
by laboratory and/or plant floatation data. It is generally accepted that adding a
surface-active agent to water lowers the surface tension of the solution due to
heteropolar nature of the reagent molecules. Thus, the surface tension of a
solution is an Indication of the activity of a frother. Frothers that strongly tower
the surface tension produce more stable froths. While the above conceptual
picture is qualitatively correct, the use of surface tension measurements alone to
screen frothers for application in floatation is limited. This is primarily due to the
highly dynamic nature of the froth, especially in the presence of partides and
turbulence. This situation Is not very different today and the terms "powerful" or
"selective", which are used to characterize frothers, have intuitive rather than
scientific meaning.
There was therefore, a need for selection of selective and powerful mixed frother
for coal floatation through blending mechanism of pure single frothing molecules.
SUMMARY OF THE INVENTION
The main object of the present invention is to provide a froth floatation process
for beneficiating coat where coarse and ultrafine coal particles are selectively
recovered in the presence of mixed chemicals system of methyl isobutyl carbinol
(MIBC) and PPG-1000 (polygloycol ether).

The process comprises characterizing of frothing molecules in two-phase (air-
water interface) and three phase coal floatation. Scientific analysis provides
linkage between two-phase frother classification Indices and coal floatation
performance parameters. This novel process will facilitate in classification of
frother and making suitable blended frother depending on the feed size
distribution.
The improvement in floatation process is governed by the novel approach for
preparation of selective and powerful mixed frother for coal floatation through
blending mechanism of pure single frothing molecules. This process contains
characterization of frothing molecules in two-phase (air-water interface) and
three phase coal floatation. Two phase frother characterization parameters are
dynamic foamability index (OR), critical coalescene concentration (CCC), air
bubble size distribution and surface activity and surfactants orientation at air-
water interface. Selectivity, kinetics and size-wise floatation performance are
three phase floatation characterization indices, Two phase fundamental frother
characterization parameters are well correlated with floatation separation
efficiency parameters. Surfactant molecules having loop and coil orientation at
interface, high dynamic foamability index value, low critical coalescene
concentration and high surface activeness are efficient for floating coarse

particles. On the other hand molecules having vertical placement at air-water
Interface, mono-fine bubble size, low dynamic foamability index and high critical
coalescence concentration are selective for ultrafine coal particles. Mixed
chemical systems of those frothing molecules are suitable coal floatation frother
for broad size distributed floatation feed.
Composition of methyl isobutyl carbinol (MIBC) and PPG-1000 in blended frotner
depends on the ratio of ultrafine and coarse fraction in floatation feed. The
methyl isobutyi carbinol can be present in an amount of 70 % and said PPG-1000
in an amount of 30 %. The blended frother of the present invention is used in a
dosage ranging from between about 0.10 kg/t to about 0.20 kg/t of floatation
feed coal. The blended frother (methyl isobutyi carbinol and PPG-1000) is
capable in floating selectively of ultrafine and coarse coal particles.
There is Improvement in 4 % clean coal yield and 1 % ash reduction with this
blended frothing molecule. It also produces dry froth by means of reduction in
froth moisture.
The process for preparation of selective and powerful mixed frother for coal
floatation through blending mechanism of pure single frothing molecules of the

present invention helps in depth understanding of frother action in coal floatation
process. This process comprises characterization of frothing molecules in two-
phase (air-water interface) and three phase coal floatation. The
floatation/surfactant molecules have loop and coil orientation at interface, high
dynamic foamability index value, low critical coalescence concentration and high
surface activeness are efficient for floating coarse particles.
The molecules have vertical placement at air-water interface, mono-fine bubble
size, low dynamic foamability index and high critical coalescence concentration
are selective for ultrafine coal particles. The mixed chemical systems of the
frothing molecules are suitable coal floatation frother for broad size distributed
floatation feed. The blended frother of the present invention containing methyl
isobutyl carblnol and PPG-1000 is showing improvement in 4 % dean coal yield
and 1 % ash reduction. It also produces dry forth by means of reduction in froth
moisture.
Thus the present invention provides a process for preparation of a selective and
powerful mixed frother coal floatation for coal benefication, comprising the steps
of: characterizing frothing / surfactant molecules into two phase (air-water
interface) flotation parameters and three phase flotation parameters; blending of

pure single frothing / surfactant molecules In the presence of a mixed chemical
system of methyl isobutyl carbinol (MIBC) and polyglycol ether PPG - 1000; and
selectively recovering coarse and ultrafine coal particles from said mixed
chemical system.
BRIEF DESCRlPTION OF THE ACCOMPANYING DRAWINGS
The invention can now be described in details with the help of the figures of the
accompanying drawings in which:
Rgure 1 shows schematic diagram of setup for testing
frothability, foam stability and bubble size.
Figure 2 shows the relationship between frother
concentration and air bubble size.
DETAILED DESCRIPTION
The process of this invention for screening the frothing molecules and preparing
blended chemicals results in an improved and efficient process for the recovery
of coal values with enhanced recovery of coarse and ultrafine particles of the

coal through addition of suitable frother in floatation. The invention of
classification of frother is described here under sequential characterization
techniques. The invention will become more readily apparent by explaining the
process with example of PPG-1000 (Polygloycol ether family), methyl Isobutyl
carbinol (Alcohol family) and Alpha-Terpinol (Alcohol family).
Two-phases frother characterization
Surface tension analysis
Ring-Plate tensiometer is used to measure the surface tension of aqueous
solutions at varying frother concentration at normal pH and room temperature.
The surface tension decreases with Increasing frother concentration as molecutes
adsorb at the liquid-air interface, Frother belonging to the polyglycol family
decreases the surface tension more sharply compare to alcohol family frotners.
It indicates that PPG-1000 is more surface active. Air-water interface affinity
order of different frbthers at lower concentration is given below:
PPG-1000>iAlpha-terplneol> MIBC

For monodisperse nonionic surfactants, at constant pH, the adsorbed amount at
air-water interface is given by the Gibbs adsorption isotherm

where r is adsorption density, y is the static surface tension, T Is the absolute
temperature, R is the ideal gas constant and C is the bulk frother concentration.
The surface area occupied by a single molecule. Aexp, at the air-liquid interface is
calculated as

Where Av is the Avagdro number
The equilibrium adsorption loading (I) and the adsorption area per molecule
(AEXp) are presented in Table 1. As can be seen in Table 1, the adsorption
loading of polyglycol ether (PPG-1000) is lower compared to alcohol family
frothers. According to it, MIBC is required less area per molecule to adsorb at
air/water interface compared to Alpha-Terpinol and PPG-1000.


The molecular adsorption area of a methyl Isobutyl carbinol molecule and an
Alpha-terpinol respectively are found to be 34 (A0)2 and 51 (A0)2. This alcohol
family molecule ranges in chain length from approximately 6 A0 to 10 A0, with a
diameter of approximately 2.0 A0. So these results are dose to the geometric
dimensions of the hydrocarbon chain, indicating methyl isobutyl carbinol stands
up at the air-water interface with -OH group oriented towards water phase and
the hydrophobic chain towards air phase. From the equilibrium surface tension
data, the molecular area of a PPG-1000 molecule is calculated 138 (A0)2. When
ail the bond angles are taken into account, the length of the molecule is found to
be 23 A0, while the diameter is 7.0 A0, giving a flat-lying molecular area of 162
(A0)2 whereas the vertical cross-sectional area is 39 (A0)2. The orientation of
PPG-1000 at the air-water interface seems to be part way between completely
lying down and completely standing up. It suggests the formation of loops and
coiling up at the interface with PPG-1000 molecule.

PPG-1000 has a much higher molecular weight (398) compared to methyl
isobutyl carbinol (102) and this higher molecular weight may lead to a more
viscous, and hence more stable, froth layer. There Is only one-OH group in
methyl isobutyl carbinol and this group will interact with water molecules to form
an oriented monolayer at the surface; but in PPG-1000, there are several
oxygenated units in the molecular chain and each unit can interact with water
molecules through hydrogen bonding, causing the molecules to tend to lie at the
surface, possibly increasing viscosity of froth and hence foam stability.
Foaming and stability
A set-up is designed for the measurement of foamability and retention time as
shown in Fig. 1. A graduated glass burette of 50 cm height and 2.5 cm diameter
is fitted with a glass frit at the bottom and connected to a mercury manometer
and air compressor. Experiments are carried out by talcing a known volume
(15ml) of the reagent solution in the burrette and passing air to the solution at a
fixed flow rate. Air is bubbled through a glass frit into the frother solution of
known concentration to create foam. The steady state foam height (foamability)
is measured as the distance between the liquid-foam interface and the top of the
foam.After the newly formed foam has been stabilized and attained an

equilibrium height (after approx 2-3 min), the steady state height is recorded.
Since the cross sectional area of glass burette is same throughout Its length, the
height is also measure of the volume of the foam generated by the air at a fixed
air flow rate for a known frother concentration.
The foam height increases with increasing air flow rate and frother
concentration. PPG-1000 gives the highest froth volume and methyl isobutyl
carblnol produces considerably lower foaming. For the testing of behavior of
floatation frothers, the dynamic foamability index is measured. This
measurement requires determination of the retention time (rt) from the slope of
linear part of the dependence of the total gas volume (V) in solution and foam
plotted versus gas flow rate (Q) for increasing frother concentration, which is
accordance with Eq. (3).

The retention time (rt) values are obtained then used to determine the dynamic
foamability index (DFI), which is defined as the limiting slope of the retention
time-concentration curve for C-> 0. Dynamic foamability index is defined as
follows (Laskowski et at., 2003)


Using the foamability data of methyl isobutyl carbinot concentration, PPG-1000
and Alpha-terpineol and Eq. (3), the foam retention time of the foamer at
different concentration is calculated. Polyglycol ether frother (PPG-1000) has
achieved maximum foaming performance at relatively low concentration. Methyl
isobutyl carbinol is showing lower retention time, which results in poor frothing
efficiency compare to other two frothers. The relative order of frother efficiency
in terms of dynamic foamability index is given below:
PPG-1000> Alpha--terpineol>MIBC
Bubble size distribution
The experimental set-up of foamability is used for imaging bubbles as shown in
Figure 1. Bubble images in foam phase are captured using a CCD camera, which
was connected to a personal computer where the visual information is stored
and processed. The images captured during sampling are automatically
processed using image analysis technique for measuring bubble size distribution.
As can be seen from Figure 2, each curve is clearly divided into two
concentration ranges, the low concentration range which can be approximated
by a step linear fit and the flat horizontal portion at higher concentration. The

intersection of the horizontal asymptote to the sauter bubble size-concentration
curve with the step linear portion can easily be determined. This Is so called
critical coalescence concentration (Cho and Laskowski, 2002; Grau et al. 2005).
The general trend for all the investigated frothers are fairly similar, the bubble
size decreases with increasing frother dosage, and at a particular concentration,
the bubble size leveled off. Frother controls bubble size by reducing bubble
coalescence in the cell and that coalescence is entirely prevented at
concentration exceeding the critical coalescence concentration in a dynamic
system. It is dear from Figure 2 that the critical coalescence concentration value
is different for each type of frother and given in Table 2. At frother
concentration exceeding the critical coalescence concentration value, the
conditions In the cell can be defined as non-coalescing. PPG-1000 Is able to
provide nonrcoalescing environment in floatation system at lowest concentration
compared to other frothers belonging to alcohol family. Methyl isobutyl carbinol
is the most effective frother in terms of bubble size reduction and the least
effective one is PPG-1000, Frothers dont only hinder coalescence but also
somehow affect bubble break-up under turbulent conditions.


A representative minus 0.5 mm size semi bituminous floatation feed coal sample
is taken in this investigation. Nature of coal sample is difficult to float Ash
analysis is carried out according to ASTM D 3174-73 standard snowed that the
sample contains 24.5 % ash. Size-wise weight and ash distribution analysis is
conducted with a representative sample of the floatation feed. Floatation feed
contains high percentage (20 %) of oversize fraction, namely -1+0.5 mm,
having 23.5 % ash. Ultra size fraction (- 0.075 mm) is having maximum weight
contribution in floatation feed content approx. 50 %. High-speed diesel oil is
used as conventional collector. Three selected non-ionic surfactants are used as
frother.

Frother performance of these chemicals are characterized in term of selectivity,
kinetics and size wise floatation performance as shown in Table 3. Methyl
isobutyl carbinol is efficient selective frother compare to polyglycol frother PPG-
1000. Rate of recovery for polyglycol frother PPG-100G is faster compared
to other alcohol frothers methyl isobutyl carbinol and Alpha-terpinonl. PPG-1000
is efficient in terms of recovery and grade for 0.5 X 0.075 mm fraction. But
alcohol frother methyi isobutyl carbinol is very effective for ultrafine fraction (-
0.075 mm) In terms of reducing ash content and floating the coal particles.


Smaller bubbles are obtained in the methyl isobutyl carbinol solution than in
PPG-1000 solutions despite the same porous frit being used, as well as the PPG-
1000 solution having considerably lower surface tensions than the methyl
isobutyl carbinol solutions at the similar concentrations. It follows that the
adsorption for larger (and more surface active) molecules of PPG-1000 must be
larger to prevent bubble from coalescence.
Dynamic foamability index value indicates the dynamic stability of foam, In which
bubbles do not easily coalesce. Critical coalescence concentration is a measure
of minimum concentration of a given frother required to prevent coalescence.
Table 2 shows that PPG-1000 is having high dynamic foamability index and low
critical coalescence concentration and methyl isobutyl carbinol having low
dynamic foamability index and high critical coalescence concentration value.
From surface activity point, PPG-1000 is showing parallel (loop and coil)
orientation at air-water interface. Methyl isobutyl carbinol is showing vertical
configuration at interface. This information predicts that PPG-1000 is more
efficient in preventing bubble coalescence and also producing more stable and
viscous foam compare to frothers belonging to alcohol family. It reflects that
higher water recovery from pulp phase to froth phase, more chance of floating
coal and ash mineral particles and less drainage rate from froth phase of coal

floatation with polyglycol frother (PPG-1000), PPG-1000 is showing faster
kinetics and less selectivity due to entrainment through water compared to
alcohol frothers. Methyl isobutyl carbinol is more efficient in bubble break-up
process, means producing finer bubbles compared to polyglycol ether frother
PPG-1000. From floatation practice, methyl isobutyl carbinol is very selective
and appropriate for the floatation of ultrafine particles and PPG-1000 is better
frother in terms of recovery and selectivity for coarse particles,. These two phase
frother characterization indices and observations are well correlating with three
phase floatation performance indexes for polyglycol ether and alcohol foaming
molecules. The frother characterization indexes are summarized in Table 4. On
the basis of observations obtained from frother classification process, PPG-1000
and methyl isobutyl carbinol are mixed in different composition. Floatation
performance with mixed frother (PPG-1000 and methyl isobutyl carbinol) Is
illustrated in Table 3. Blended frother is showing improvement in performance of
recovery and grade of ultrafine and coarse coal fraction. So overall it is showing
enhanced floatation efficiency.



A good matching in critical coalescence concentration and dynamic foamability
index values of PFG-1000 and methyl isobutyl cgrbinol is reported between this
invention and work done since, despite the difference in experimental measuring
systems. It also reflects that dynamic foamability index and critical coalescence
coricentration can be material properties, for frothing molecules. The polyglycol
ether and alcohol frothers are presenting good association between fundamental
two phase frother characterization indices and coal floatation performance.
REFERENCES CITED
U.S. Patent No. 4, 582, 596 issued April 15,1986
U.S. Patent No. 4, 915, 825 issued April 10,1990
U.S. Patent No. 4, 272, 364 issued June 09,1981
U.S. Patent No. 4, 504, 385 issued March 12,1985
U.S. Patent No. 5,304, 317 issued April 19,1994
U.S. Patent No. 3,710,939 issued January 16,1973
U.S. Patent No. 4,606, 818 issued August 19,1986
U.S. Patent No. 4, 761, 223 issued August 02,1988
U.S. Patent No. 4, 925, 559 issued May 15,1990

Cho, Y.S., Laskowski, J.S., 2002. Bubble coalescence and Its effect on dynamic
foamability. Can. X Chem. fcng. 80, 299-305.
Grau, R.A., Laskowski, J.S., and Heiskanen, K., 2005. Effect of frothers on
bubble size. Int J. Mineral Processing, 76(8), 225-233.
Laskowski, J.S., Tlhone, T., Williams, P. and Ding, K., 2003. Fundamental
properties of polyoxypropylene alkyl ether floatation frothers. Int. 3. Mineral
Processing, 72, 289-299.

WE CLAIM:
1. A process for preparation of a selective and powerful mixed frother for
Coal flotation through blending mechanism of prime single frothing
molecules comprising the step of:
- a two phase (air-water interface) floatation characterized
parameter comprising a surface activity, a dynamic floatation index,
a critical coalescence concentration and bubble size at ccc;
- a three phase (air-water solid interface) floatation characterized
parameter comprising a selectivity, kinetics, size wise floatation
performance;
- blending of pure single frothing molecules in the presence of a
mixed chemical system of methyl isobutyl carbinol (MIBC) and
polyglycol ether PPG-1000; and
characterized in that the two phase frother (air-water interface)
having high DFI, low ccc and high surface activeness are efficient
for floating coarse particles and a three phase frother (air-water
solid interface) having parameter selectivity, kinetics, size-wise
floatation performance, low DFI and high ccc are efficient for
floating fine particles from the coal distribution.
2. The process as claimed in claim 1, wherein said two phase
characterization parameters are dynamic foamability index (DFI),
critical coalescence concentration (CCC), air-bubble size distribution
and surface activity and surfactant orientation at air-water interface.

3. The process as claimed in claim 1, wherein said three phase
characterization parameters are selectivity, kinetics and size-wise
floatation performance.
4. The process as claimed in claim 2, wherein said flotation / surfactant
molecules have a loop and coil orientation at the interface with high
dynamic foamability index (DPI), low critical coalescence concentration
values, and high surface, activeness for floating coarse particles.
5. The process as claimed in daim 2, wherein vertical placement at said air
water interface, mono fine bubble size, low DFI and high CCC are
selected for ultrafine coal partides.
6. The process as claimed in daim 1, wherein the composition of MIBC and
PPG-1000 in the blended frother depends on ratio of ultrafine and coarse
fractions in the flotation feed.
7. The process as claimed in daim 6, wherein said composition is 70 %
MIBC and 30 % PPG -1000.

8. The process as claimed in preceding claims wherein said blended frother
comprising MIBC and PPG - 1000 is capable of selectively floating
ultrafine and coarse coal particles.
9. The process as claimed in preceding claims 6, wherein the dosage of said
blended frother used is preferably between 0.10 kg/t to 0.20 kg/t of
floatation feed coal.


ABSTRACT

A NOVEL PROCESS FOR PREPARATION OF A SELECTIVE AND
POWERFUL MIXED FROTHER FOR COAL FLOATATION
The present invention is provided with a process for preparation of a selective
and powerful mixed frother for Coal flotation through blending mechanism of
prime single frothing molecules comprising a two phase (air-water interface)
floatation characterized parameter comprising a surface activity, a dynamic
floatation index, a critical coalescence concentration and bubble size at ccc; a
three phase (air-water solid interface) floatation characterized parameter
comprising a selectivity, kinetics, size wise floatation performance; blending of
pure single frothing molecules in the presence of a mixed chemical system of
methyl isobutyl carbinol (MIBC) and polyglycol ether PPG-1000.

Documents:

00907-kol-2006-abstract.pdf

00907-kol-2006-correspondence others.pdf

00907-kol-2006-correspondence-1.1.pdf

00907-kol-2006-description(provisional).pdf

00907-kol-2006-drawings.pdf

00907-kol-2006-form-1-1.1.pdf

00907-kol-2006-form-1.pdf

00907-kol-2006-form-2.pdf

00907-kol-2006-form-3.pdf

00907-kol-2006-general power of authority.pdf

907-KOL-2006-(14-02-2012)-ABSTRACT.pdf

907-KOL-2006-(14-02-2012)-AMANDED CLAIMS.pdf

907-KOL-2006-(14-02-2012)-DESCRIPTION (COMPLETE).pdf

907-KOL-2006-(14-02-2012)-DRAWINGS.pdf

907-KOL-2006-(14-02-2012)-EXAMINATION REPORT REPLY RECEIVED.pdf

907-KOL-2006-(14-02-2012)-FORM-1.pdf

907-KOL-2006-(14-02-2012)-FORM-2.pdf

907-KOL-2006-(14-02-2012)-OTHERS.pdf

907-KOL-2006-(25-07-2012)-CORRESPONDENCE.pdf

907-KOL-2006-ABSTRACT-1.1.pdf

907-kol-2006-abstract.pdf

907-KOL-2006-CLAIMS-1.1.pdf

907-kol-2006-claims.pdf

907-KOL-2006-CORRESPONDENCE 1.2.pdf

907-KOL-2006-CORRESPONDENCE-1.1.pdf

907-KOL-2006-CORRESPONDENCE-1.3.pdf

907-kol-2006-correspondence.pdf

907-KOL-2006-DESCRIPTION (COMPLETE)-1.1.pdf

907-kol-2006-description (complete).pdf

907-KOL-2006-DRAWINGS.pdf

907-KOL-2006-EXAMINATION REPORT.pdf

907-KOL-2006-FORM 1.pdf

907-KOL-2006-FORM 18-1.1.pdf

907-kol-2006-form 18.pdf

907-KOL-2006-FORM 2-1.1.pdf

907-kol-2006-form 2.pdf

907-KOL-2006-FORM 3.pdf

907-KOL-2006-FORM 5-1.1.pdf

907-kol-2006-form 5.pdf

907-KOL-2006-GPA.pdf

907-KOL-2006-GRANTED-ABSTRACT.pdf

907-KOL-2006-GRANTED-CLAIMS.pdf

907-KOL-2006-GRANTED-DESCRIPTION (COMPLETE).pdf

907-KOL-2006-GRANTED-DRAWINGS.pdf

907-KOL-2006-GRANTED-FORM 1.pdf

907-KOL-2006-GRANTED-FORM 2.pdf

907-KOL-2006-GRANTED-SPECIFICATION.pdf

907-KOL-2006-OTHERS.pdf

907-KOL-2006-REPLY TO EXAMINATION REPORT.pdf

907-KOL-2006-SPECIFICATION.pdf


Patent Number 253542
Indian Patent Application Number 907/KOL/2006
PG Journal Number 31/2012
Publication Date 03-Aug-2012
Grant Date 30-Jul-2012
Date of Filing 07-Sep-2006
Name of Patentee TATA STEEL LIMITED.
Applicant Address RESEARCH AND DEVELOPMENT DIVISION JAMSHEDPUR-831001, INDIA
Inventors:
# Inventor's Name Inventor's Address
1 GUPTA, A.K. TATA STEEL LIMITED. RESEARCH AND DEVELOPMENT DIVISION JAMSHEDPUR-831001
2 BANERJEE, PRADIP KUMAR TATA STEEL LIMITED . RESEARCH AND DEVELOPMENT DIVISION JAMSHEDPUR-831001
PCT International Classification Number B03D
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA