FIELD OF INVENTION:
[0001]. The present invention relates to a novel compound such as polyethylene
glycol and polypropylene glycol derivatives or more particularly compound of
formula (I) to be used as effective reagent for separating of low grade coal from
gangue materials.
[0002]. Further the present invention also provides a novel method of
synthesizing the floatation reagents using said polyethylene glycol and
polypropylene glycol derivatives.
BACKGROUND OF INVENTION:
[0003]. In the coal floatation process, the naturally hydrophobic coal particles
are floated while the hydrophilic gangue particles are collected as tailings.
Collector is added prior to floatation to enhance the surface hydrophobicity of
the coal particles whereas frother is used for decreasing the surface tension of
air bubbles, thereby assisting the formation of ultrafine bubbles. Standard No.
2 fuel oil and MIBC (methyl isobutyl carbinol) are commonly used as collector
and frother, respectively, in coal floatation processes adopted worldwide. At Tata
Steel coal washeries treating captive coals, synthetic collector made by Nalco
Chemicals is used in place of No. 2 fuel oil as coal collectors. Commercially
available frother also from Nalco Chemicals is used as frother for stabilizing air
bubbles to enhance coal floatation process.
[0004]. Coal is formed mainly by the process of sedimentation and the organic
composition of coal differs based on the coalification i.e. metamorphic formation
of coal. Organic matter of coal is formed from a variety of macerals with distinct
physical and chemical properties. Subsequently, inorganic matter in coal mainly
comprises of different mineral types. Approximately 60 different types of
minerals are found in coal and some of the major minerals occur in form of
silicates, sulfides, carbonates and oxides (Spackman, 1989).
PRIOR ART
[0005]. Many researchers have showed that straight chain aliphatic oily
collectors perform poorly for low grade coals and ionic collectors should be

preferred in case of low grade coals. A composite mixture of fuel oil no. 2 and
fuel oil no. 6 in a ratio of 4:1 was found to be effective for floating low-grade coal
(Wen & Sun, 1981). Oil droplets formed from this mixture found to have a higher
positive charge and this higher positive charge was attributed due to some
polycyclic structures present in fuel oil no.6 containing amine, sulphur, salts of
nickel and vanadium (Guthrie, 1960).
[0006]. It was later found that low grade coal surface layer can be dissolved
using caustic soda solution. In alkaline medium, hydration of low grade coal
surface could be reduced, which can increase the hydrophobicity of low grade
coal particles. A cationic organic compound such as benzidine in benzoyl alcohol
was used at 850□ for reduction of oxidized groups and coal electro-kinetic
behaviour was found to be restored (Wen & Sun, 1977). Cyclic hydrocarbons
such as cyclodecane (C10H18) were found to have a slightly better performance
as compared to dodecane. It was later found that introduction of benzene ring in
collector can increase the collector performance as it tends to form strong π
bonding with coal aromatic structure (Figure 2.12). Also, presence of hydrophilic
groups such as ethoxy and phenol groups on collector can further enhance the
collector capability to interact with hydrophilic groups on coal surface through
hydrogen bonding.
[0007]. Ethoxylated nonyl phenol was found to be better collector than
dodecane for Illinois No. 6 coal (Harris, Diao, & Fuerstenau, 1995) as it was
found to be adsorbed both on hydrophobic and hydrophilic surfaces (Aston,
Lane, & Healy, 1989). Therefore, a combination of hydrophobic aliphatic
hydrocarbon chain along with aromatic compounds and hydrophilic groups
could be effective as collector for low grade coals. However, the number of
hydrophilic groups in the collector should be kept limited as an increase in
number of hydrophilic groups surrounding coal could negatively impact the coal
floatation.
[0008]. Attempts have been made to develop new frothers as mentioned in the
patents mentioned in U.S. Patent No. 4, 582, 596 issued April 15, 1986, 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. 3, 710, 939 issued January 16, 1973, U.S.
patent No. 4, 761, 223 issued August 02, 1988, U.S. Patent No. 4,915, 825
issued April 10, 1990.
[0009]. Therefore, in order to increase the floatability of low grade coal particles,
an extensive research has been conducted in past few decades to develop various
chemical reagents. However, few of these chemicals have been used in the
industry either due to economic feasibility or environmental regulations. Floating
low grade coal with acceptable combustible recovery and sufficient separation
efficiency remains a difficult task confronting the coal preparation industry.
[00010].But none of the compounds provide substantial effective reagent for
floatation of low grade coal from the gangue materials.
[00011]. The present invention meets the long-felt need for providing floatation
reagents which are effective.
OBJECTS OF THE INVENTION
[00012]. It is therefore the principal object for the present invention to provide a
method of preparing novel floatation reagents such as polyethylene glycol based
derivatives, which can be effectively used for floatation of low grade coal particle.
[00013]. Another object of the present invention is to provide a novel chemical
reagent which is effective in floatation of low grade coal from the gangue
materials.
[00014]. Yet another object of the present invention is to provide a method of
producing chemical reagents with 90-95% purity and 75-80% yield, which is
used for floatation of low grade coal.
[00015]. Another object of the present invention to provide a novel chemical
reagent for floatation of low grade coal, which is economic and environmentally
friendly.
SUMMARY OF INVENTION
[00016]. One or more drawbacks of conventional floatation reagents are
overcome, and additional advantages are provided through the method as

claimed in the present disclosure, Additional features and advantages are
realized through the technicalities of the present disclosure. Other embodiments
and aspects of the disclosure are described in detail herein and are considered
to be part of the claimed disclosure.
[00017]. A novel polyethylene glycol and polypropylene glycol derivatives be used
as a floatation reagent for low grade coal, said compound having formula (I);
wherein ‘R’ can be an atom ranging from C4 to C8 and ‘n’ is 3 to 5.
[00018]. Further, there is also provided a method for preparing a floatation
reagent such as polyethylene glycol and polypropylene glycol derivatives
comprises the steps of: i) taking 2-ethyl hexanol in a container and reaction
occurs with of sodium hydride in a solvent to form sodium alkoxide as an
intermediate; ii) reaction of the intermediate with propylene oxide in inert
environment; iii) cooling down of the reaction product at a room temperature for
a suitable duration of 6 hours; iv) quenching of the compounds with water and
extracted with ethyl acetone for twice; v) subjected to formation of emulsion, as
clear separation through extraction was not possible; and vi) slow isolation of
the final product as pale-yellow liquid, wherein the floatation reagent produced
with 70% yield having 90 to 95% purity.
[00019]. Various objects, features, aspects, and advantages of the inventive
subject matter will be more apparent from the following details of preferred
embodiments, along with the accompanying drawing figures.
[00020]. It is to be understood that the aspects and embodiments of the
disclosure described above may be used in any combination with each other.
Several of the aspects may be combined to form a further embodiment of the
disclosure.
[00021]. The foregoing summary is illustrative only and is not intended to be in
any way limiting. In addition to the illustrative aspects, embodiments, and
features described above, further aspects, embodiments will become apparent
by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
[00022]. The illustrated embodiments of the subject matter be best understood
by reference to the drawings. The following description is intended only by way
of example, and simply illustrates certain selected embodiments of method,
systems, that are consistent with the subject matter as claimed herein, wherein:
[00023].Figure 1 illustrates H-NMR spectra of the floatation reagents.
[00024].Figure 2 illustrates FT-IR spectra of coal.
[00025].The figures depict embodiments of the disclosure for purposes of
illustration only. One skilled in the art will readily understand from the following
description that alternative embodiments of the structures and methods
illustrated herein may be employed without departing from the principles of the
disclosure described herein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[00026]. While the embodiments of the disclosure are subject to various
modifications and alternative forms, specific embodiment thereof have been shown
by way of the figures and will be described below. It should be understood,
however, that it is not intended to limit the disclosure to the particular forms
disclosed, but on the contrary, the disclosure is to cover all modifications,
equivalents, and alternative falling within the scope of the disclosure.
[00027]. It is to be noted that a person skilled in the art would be motivated from
the present disclosure to arrive at a method for preparing a floatation reagent such
as polyethylene glycol and polypropylene glycol derivatives. Such method may vary
based on configuration of one or more ingredients. However, such modifications
should be construed within the scope of the disclosure. Accordingly, the drawings
illustrate only those specific details that are pertinent to understand the
embodiments of the present disclosure, so as not to obscure the disclosure with
details that will be clear to those of ordinary skill in the art having benefit of the
description herein.

[00028]. As used in the description herein and throughout the claims that follow,
the meaning of “a”, “an”, and “the” includes plural reference unless the context
clearly dictates otherwise.
[00029]. The terms “comprises”, “comprising”, or any other variations thereof
used in the disclosure, are intended to cover a non-exclusive inclusion, such that
a method, reagent, floatation, coal that comprises a list of components does not
include only those components but may include other components not expressly
listed or inherent to such method. In other words, one or more elements in a
method proceeded by “comprises…..a” does not, without more constraints,
preclude the existence of other elements or additional elements in the method.
[00030]. The present embodiment of the invention relates to a novel method for
preparing of floatation reagents for floatation of low grade coal from the gangue
materials, which can be used as a selective and powerful frother for coal
beneficiation.
[00031]. The floatation reagents used for the coal beneficiation is polyethylene
glycol derivative comprising of ester group or more particularly and mixtures of
polyethylene glycol and polypropylene glycol.
[00032]. The structure of the novel compound is given as formula (I)


[00034]. The process for preparing the floatation reagent comprises the steps of:
wherein ‘R’ can be an atom ranging from C4 to C8 and ‘n’ is 3 to 5.
[00033]. One example of such compound is

i) taking 2-ethyl hexanol in a container and reacts with 1.2 equivalent of
sodium hydride in tetrahydrofuran to form sodium alkoxide as an intermediate;
ii) reaction of the intermediate with 3 equivalent propylene oxide at a
temperature of 0°C in nitrogen environment;
iii) cooling down of the reaction product at a room temperature for a
duration of 6 hours;
iv) quenching of the compounds with water and extracted with ethyl
acetone for twice;
v) subjected to formation of emulsion, as clear separation through
extraction was not possible;
vi) slow isolation of the remaining compound as pale-yellow liquid with
70% yield.
[00035]. The resultant compound has undergone different analysis for example
1H-NMR analysis.
[00036]. Figure 1 illustrates H-NMR spectra of the reagents.
[00037].Different tests have been conducted for different properties of the
floatation reagents.
Solubility of the Reagents:
[00038].The compound extracted by the method described above is sparingly
soluble in water.
Contact angle:
[00039]. As the compound is intended to use as surface acting agents with
frothing capabilities to support coal floatation application, it was subjected to
contact angle measurements. The contact angle is found to be 64.81.
Characterization of Coal:
[00040]. Raw coal is collected from the feed material of Tata Steel washery
present in West Bokaro, Dist. Ramgarh, State- Jharkhand. The raw coal is then
taken to R&D laboratory of Tata Steel for further study. Raw coal is screened at

0.5mm to collect the undersize of the screen which is feed to floatation cell. The
feed to floatation is then subjected to FT-IR analysis as well as proximate analysis
to understand the mineral oxides present in the coal.
[00041].Ash content and contact angle of coal are provided in Table 1:

Table 1
Ash content 29.06%
Contact angle 57.02°
[00042]. Table 2 provides quantities of different mineral oxides present in ash
produced from coal, which is given below:

Element Quant (%) Element Quant (%)
Fe (T) 2.25 P 0.12
Al2O3 6.95 TiO2 0.67
SiO2 17.16 MnO 0.43
CaO 0.51 Ce2O3 0.0070
MgO 0.22 C & O Rest
Floatation experiments:
[00043].Chemical and Materials for the floatation test:
[00044]. A f1otatIon cell Denver D-12, 2.5-lit capacity is used for floatation test.
This unit has a baffle arrangement at bottom to avoid swirling of the slurry within
the cell and an Impeller is provided for proper mixing of the slurry, the speed of
which can be controlled by a speed regulator.
[00045]. A compressor is provided to supply air to the cell in the range of 0-20
litres/min (1pm) in an interval of 1 1pm. The cell has an automatic pulp level

controller through make up water tank and froth removal system. For each batch
floatation, 250 gm fine coal sample of size <0.5mm is allowed to wet for 1 hour in
known volume of water. It is transferred into the 2.5-lit capacity Denver cell.
Additional water is added to maintain required pulp density i.e. 10-12% solid
content. Slurry is allowed to wet for 3 minutes at the impeller speed of 850 rpm.
Nalco synthetic collector is added and conditioned for 3 minutes. After
conditioning, requisite amount of frother (Nalco as well as new reagent) is added.
It is again conditioned for another 3 minutes. The cell is filled with water up to
the marked height; the air inlet valve is opened and kept at 2 lpm. The froth
samples are collected after 30 (F1), 60 (F2), 120 (F3), and 240 (F4) seconds of
floatation. After the final froth sample is collected, the machine is stopped. The
froth products and the tailings (the part that remaining inside the floatation cell)
is dried, weighed and analyzed for their ash content.
[00046]. Table 3 includes different parameters of laboratory floatation tests,
which is given below:

Table 3
Parameters
Weight of coal 250 gm
Pulp density 10 %
Collector dosage (synthetic collector of Nalco
Chemicals) 500 ppm
Frother dosage (Nalco chemicals and new
reagent) 100 ppm
Agitator speed 850 rpm
Air supply rate 4 1pm

Results and Discussions:
[00047]. Laboratory floatation tests are done with synthetic collector from Nalco
chemicals and new reagent is used as frother at dosages of 50, 100 and 200ppm.
The results obtained for new frother are compared with floatation test results
obtained using Nalco collector and Nalco frother at the same dosages as
mentioned above.
[00048]. The results of Nalco frother in different quantity is given in Tables such
as Table 4, 4a and 4b, whereas the data of new frother in different quantities are
provided in Tables 5, 5a and 5b

Table 4
Nalco collector: 500ppm and Nalco frother: 50ppm
Fractions Ash% Cum. yield. % Cum. ash%
F1 9.28 27.59 9.28
F2 7 40.00 8.57
F3 15.17 48.97 9.78
F4 28.61 62.07 13.76
Tailings 40.38 100.00 24.90
Table 5
Nalco collector: 500ppm and new frother: 50ppm
Fractions Ash% Cum. yield. %
F1 9.28 31.72
F2 7 40.69
F3 15.17 49.66
F4 28.61 62.76
Tailings 40.38 100.00

Table 4a
Nalco collector: 500ppm and Nalco frother: 100ppm
Fractions Ash% Cum. yield. % Cum. ash%
F1 12.05 19.29 11.39
F2 14.92 49.55 13.08
F3 18.57 60.76 13.88
F4 28.56 64.98 14.76
Tailings 46.26 100.00 24.90
Table 5a
Nalco collector: 500ppm and new frother: 100ppm
Fractions Ash% Cum. yield. % Cum. ash%
F1 12.18 26.84 11.60
F2 14.07 50.90 12.45
F3 17.64 60.54 13.15
F4 30.09 64.54 14.11
Tailings 46.75 100.00 24.90
Table 4b
Nalco collector: 500ppm and Nalco frother: 200ppm
Fractions Ash% Cum. yield. % Cum. ash%
F1 9.25 6.21 9.25
F2 9.65 17.93 9.51
F3 10.69 33.10 10.05
F4 21.22 63.45 15.39
Tailings 41.41 100.00 24.90

Table 5b
Nalco collector: 500ppm and new frother: 200ppm
Fractions Ash% Cum. yield. % Cum. ash%
F1 10.65 28.38 10.65
F2 12.38 39.86 11.15
F3 15.23 50.68 12.02
F4 23.7 64.86 14.57
Tailings 41.6 100.00 24.07
[00049]. From the above-mentioned tables, it is observed that at low frother
dosage of 50 ppm, the yield for new frother is marginally higher by 0.65 units
from Nalco frother. At median dosage of 100 ppm (used in coal washeries of Tata
Steel), yield obtained for Nalco frother is 64.98% at ash content of 14.76%
whereas yield for new frother is 64.54% at lower ash level of 14.11%. If
normalisation of ash content of clean coal is done at 14.76%, predicted yield for
new frother through linear regression would be 67.1% which is 2.12 units higher
than that obtained for Nalco frother. At higher frother dose of 200ppm, the yield
obtained for new frother is observed to be higher by1.41 units at lower clean coal
ash level of 14.57% compared to 15.39% ash content measured with application
of Nalco frother.
[00050]. Each of the appended claims defines a separate invention, which for
infringement purposes is recognized as including equivalents to the various
elements or limitations specified in the claims. Depending on the context, all
references below to the “invention” may in some cases refer to certain specific
embodiments only. In other cases, it will be recognized that references to the
“invention” will refer to subject matter recited in one or more, but not necessarily
all, of the claims.
[00051]. Groupings of alternative elements or embodiments of the invention
disclosed herein are not to be construed as limitations. Each group member can
be referred to and claimed individually or in any combination with other members

of the group or other elements found herein. One or more members of a group
can be included in, or deleted from, a group for reasons of convenience and/or
patentability. When any such inclusion or deletion occurs, the specification is
herein deemed to contain the group as modified thus fulfilling the written
description of all groups used in the appended claims.
Equivalents:
[00052].With respect to the use of substantially any plural and/or singular terms
herein, those having skill in the art can translate from the plural to the singular
and/or from the singular to the plural as is appropriate to the context and/or
application. The various singular/plural permutations may be expressly set forth
herein for sake of clarity.
[00053]. It will be understood by those within the art that, in general, terms used
herein, and especially in the appended claims (e.g., bodies of the appended
claims) are generally intended as “open” terms (e.g., the term “including” should
be interpreted as “including but not limited to”, the term “having” should be
interpreted as “having at least”, the term “includes” should be interpreted as
“includes but is not limited to”, etc.). It will be further understood by those within
the art that if a specific number of an introduced claim recitation is intended,
such an intent will be explicitly recited in the claim, and in the absence of such
recitation no such intent is present. For example, as an aid to understanding, the
following appended claims may contain usage of the introductory phrases “at
least one” and “one or more” to introduce claim recitations. However, the use of
such phrases should not be construed to imply that the introduction of a claim
recitation by the indefinite articles “a” or “an” limits any particular claim
containing such introduced claim recitation to inventions containing only one
such recitation, even when the same claim includes the introductory phrases “one
or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a”
and/or “an” should typically be interpreted to mean “at least one” or “one or
more”); the same holds true for the use of definite articles used to introduce claim
recitations. In addition, eve it a specific number of an introduced claim recitation
is explicitly recited, those skilled in the art will recognize that such recitation

should typically be interpreted to mean at least the recited number (e.g., the bare
recitation of “two recitations”, without other modifiers, typically means at least
two recitations, or two or more recitations).
[00054].The above description does not provide specific details of the method of
the various parameters. Those of skill in the art are familiar with such details,
and unless departures from those techniques are set out, techniques, known,
related art or later developed designs and materials should be employed. Those
in the art are capable of choosing suitable manufacturing and design details.
[00055].The terminology used herein is for the purpose of describing particular
embodiments only and is not intended to be limiting of the present disclosure. It
will be appreciated that several of the above-disclosed and other features and
functions, or alternatives thereof, may be combined into other methods or
applications. Various presently unforeseen or unanticipated alternatives,
modifications, variations, or improvements therein may subsequently be made by
those skilled in the art without departing from the scope of the present disclosure
as encompassed by the following claims.
[00056]. The claims, as originally presented and as they may be amended,
encompass variations, alternatives, modifications, improvements, equivalents,
and substantial equivalents of the embodiments and teachings disclosed herein,
including those that are presently unforeseen or unappreciated, and that, for
example, may arise from applicants/patentees and others.
[00057]. While various aspects and embodiments have been disclosed herein,
other aspects and embodiments will be apparent to those skilled in the art. The
various aspects and embodiments disclosed herein are for purposes of illustration
and are not intended to be limiting, with the true scope and spirit being indicated
by the following claims.

WE CLAIM:
1. A novel polyethylene glycol and polypropylene glycol derivatives be used as a
floatation reagent for low grade coal, said compound having formula (I)

wherein ‘R’ can be an atom ranging from C4 to C8 and ‘n’ is 3 to 5.
2. The novel compound as claimed in claim 1, wherein said compound is

3. A method for preparing a floatation reagent such as polyethylene glycol and
polypropylene glycol derivatives comprises the steps of:
i) taking 2-ethyl hexanol in a container and reaction occurs with of sodium
hydride in a solvent to form sodium alkoxide as an intermediate;
ii) reaction of the intermediate with propylene oxide in inert environment;
iii) cooling down of the reaction product at a room temperature for a suitable
duration;
iv) quenching of the compounds with water and extracted with ethyl acetone
for twice;
v) subjected to formation of emulsion, as clear separation through extraction
was not possible; and
vi) slow isolation of the final product as pale-yellow liquid;
wherein the floatation reagent produces with 70% yield having 90 to 95% purity.

4. The method for preparing the floatation reagent as claimed in claim 3, wherein
2-ethyle hexanol reacted with 1.2 equivalent of sodium hydride.
5. The method for preparing the floatation reagent as claimed in claim 3, wherein
the solvent used for reaction of 2-ethylenehexanol with sodium hydride is
tetrahydrofuran.
6. The method for preparing the floatation reagent as claimed in claim 3, wherein
3 equivalent of propylene oxide has been utilized for reaction with the
intermediate.
7. The method for preparing the floatation reagent as claimed in claim 3, wherein
the reaction between propylene oxide and intermediate occurs at a temperature
of 0°C in nitrogen environment.
8. The method for preparing the floatation reagent as claimed in claim 3, wherein
the product has cooled down for a duration of 6 hours.