FIELD OF INVENTION:
[0001]. The present invention relates to a flotation reagent for removal of silica from iron ore
fines.
[0002]. The reagent is a mixture of amine from alkyl group and a high surface area silica of
Silsesquioxane group. The cationic alumina silicates are being removed by this invention in the
form of collector in reverse flotation of iron ore slimes.
[0003]. The POSS (Polyhedral Oligomeric Silsesquioxane) and the amine additives have
showed a selective decrease in the amount of silica varying from the pH of 3-10 where basic
medium was found to be the best with respect to recovery and yield.
BACKGROUND OF THE INVENTION
[0004]. Due to the degrading quality of iron ore, large quantity of fines is generated. The fines
and ultra-fines cannot be beneficiated by gravity separation techniques and as surface active
forces dominate in this size range. Hence process like froth flotation must be deployed for
beneficiation. Reverse flotation is one of the most common and prominent beneficiation
technique for iron ore fines wherein alumina-silicates are separated from the iron rich phases.
The major challenge is that it is extremely difficult to separate alumina from hematite due to
their similarities in the crystal structure. This causes them to behave similarly towards a wide
variety of reagents. To tackle this problem of flotation, collectors are used which must be
specific to the ore where the selectivity depends mainly on the functional group and binding
mechanism.
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[0005]. One of the most abundant form of impurity found is the kaolinite which is present in
iron ore. Iron ore reverse flotation technique has only been considered due to high amount of
iron present as compared to the gangue materials. The reagents used for flotation mostly govern
the separation process apart from the operating conditions. Typical iron ore reverse flotation
process consists of Dispersants, Depressants and Collector which are selected based on the
interaction properties with the iron ore. Collector is an inorganic polar functional group with a
hydrocarbon non polar chain and sometimes a polymeric compound. The functional groups
determine the selectivity of the compound on the gangue materials which might be due to any
kind of interactions like ionic bonding, covalent bonding, hydrophobic-hydrophilic interaction.
The ability to adsorb the gangue materials in the process of flotation depends on the steric,
physical, chemical and thermodynamic properties. Long chain amines are found to have a good
effect on the iron ore flotation performance for silica based impurities during reverse froth
flotation. Silica selective flotation reagents are common but yield and recovery are the prime
factors that are considered in the flotation process. Reagents which have been reported till date
are not able to balance the optimum performance in both yield and recovery for the removal of
alumina silicates.
[0006]. The present invention has high recovery of silica along with the optimum yield.
OBJECTS OF THE INVENTION:
[0007]. It is therefore an object for the present invention is to propose a flotation reagent for
removal of silica from iron ore fines.
[0008]. Another object of the present invention is to propose a method of beneficiation of iron
ore by reverse flotation method.
[0009]. Further object of the present invention is to propose a reagent comprising
Silsesquioxane with an amine component of alkyl amines.
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[00010]. Still another object of the present invention is to propose a process of reverse flotation
of iron ore fines having silicate minerals as their major gangue mineral.
BRIEF DESCRIPTION OF THE INVENTION:
[00011]. 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.
[00012]. The present invention relates to a novel flotation reagent for removal of silica from
iron ore fines comprising: polyhedral oligomeric silsesquioxane and amine additives.
[00013]. 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.
[00014]. 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.
[00015]. 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 DRAWINGS
[00016]. 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
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illustrates certain selected embodiments of method, systems, that are consistent with the subject
matter as claimed herein, wherein:
[00017]. Figure 1 illustrates is a flow diagram of the synthesised.
[00018]. Figure 2 illustrates FT-IR of POSS compound
[00019]. Figure 3 illustrates Si-NMR of POSS compound
[00020]. The figure 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 PRESENT INVENTION
[00021]. One or more drawbacks of conventional flotation reagent used in the process of reverse
froth flotation of iron ore slimes and also the method of removal of silica from iron ore in steel
industry 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.
[00022]. It is to be noted that a person skilled in the art would be motivated from the present
disclosure to arrive at a novel flotation reagent for reverse froth flotation and a method of
removal of silica from iron ore. Such reagent and 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
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with details that will be clear to those of ordinary skill in the art having benefit of the description
herein.
[00023]. 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.
[00024]. 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, LD slag, steel,
slurry, filtrate 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.
[00025]. Hereinafter, a description of an embodiment relates to reagents containing high surface
area along with amine availability have strong binding towards the silica content available in
the froth flotation process. In order to overcome the hydrophilic forces long chain amine base
is required. The mineral reagent should be highly interactive among themselves apart from being
interactive with air bubble interface. Reagent carrying the silica particles to froth require
hydrophobic interaction among them. These kind of reagents which are selective towards the
silica and hydrophobic in nature are synthesized and flotation experiments have been performed
at different pH conditions to find out the effect of variable on flotation performance. These
reagents have good interaction with minerals. The reagent is synthesized in a manner that it
would give acid base reaction on silica for effective flotation performance.
[00026]. Take POSS (1 eq.) and add (1 eq.) of water. Heat the reaction up to 50oC to 70oC and
stir at the same temperature then add Octylamine (1 eq.) and wait for 3 to 4 h under nitrogen
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atmosphere. The progress of the reaction was monitored by TLC. After the completion of the
reaction, add water to collect the final formulated compound. Add acetone stir for 30 min pale
white solid precipitate out, filter the solid and wash with acetone, suck dry the compound under
vacuum oven at 30oC to 40oC. Compound obtained as a white Nano composite solid with 80%.
[00027]. Flotation tests were performed with feed of iron ore sample as 500 grams which is of
200# mesh underflow using Possamine compound as collector. Alumina content in the feed is
about 3% - 4% while silica content is about 2%-3%. All of the flotation experiments obtain froth
and tailings as the final products. As it is a reverse flotation froth contains the gaunge materials
in high quantity and iron in less quantity while the tailings contain the high iron content and
traces of gaunge materials. Hence froth is considered to be the impurity and tailings is
considered to be the concentrate. The Possamine compound lead the final concentrate product
to a silica content of 0.9% and 1.1% silica and 3.6% and 3.5% alumina respectively. The
commercial silica removal agents require high amount of collector dosage while this invention
serves about 1/5th as required from commercial reagents due to its high surface area. With the
available collector the silica was able to come down to 0.9%-1.1% and alumina was reduced to
3.5% in the concentrate.
At pH 9 (Possamine)
Fe(t)% Al2O3 (%) SiO2 (%) Yield (%)
Feed 59-62 3.2-4.6 2.7-3.9 100
Conc. Obtained by
reagent (Possamine) 62.5-64.2 2.6-3.4 0.9-1.5 75-80
Conc. Obtained by
Commercial collector
(oleic acid)
62-63 2.9-3.8 1.5-2.0 60-75
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[00028]. In summary, long chain Polyhedral Oligomeric Silsesquioxane amines (Possamine)
showed a good potential and selectivity for iron in reverse floatation process giving effective
results.
EXAMPLES
[00029]. Take POSS (1 eq.) and add (1 eq.) of water. Heat the reaction up to 60oC and stir at
the same temperature then add Octylamine (1 eq.) and wait for 4 h under nitrogen atmosphere.
The progress of the reaction was monitored by TLC. After the completion of the reaction, add
water to collect the final formulated compound. Add 2 vol. of acetone stir for 30 min pale white
solid precipitate out, filter the solid and wash with 0.5 vol. of acetone, suck dry for 15 min the
compound under vacuum oven at 40oC. Compound obtained as a white Nano composite solid
with 80%.
[00030]. Flotation experiments:
Chemical and Materials for the flotation test:
1. Weight of iron ore sample: 500g
2. Size of the iron ore sample: -200# (mesh)
3. Collector used: Synthesized reagents
4. Depressant used: causticized starch solution (1000 ppm)
5. pH regulator: NaOH, AcOH
6. pH maintained: 8.5-9.5
7. pH meter
8. trays, weighing balance, beakers, droppers, conical flasks, glass rod
Preparation of causticized starch solution
1. 200mL of water was taken in a beaker.
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2. It was heated in a magnetic stirrer up to a temperature of 80 degrees centigrade.
3. Then 1 g of NaOH flakes was added.
4. Then 2 g of potato starch was added slowly with continuous stirring for 2 to 5 minutes.
5. Then the solution was quenched as soon as possible.
[00031]. Flotation experiment at pH 9
Procedure Followed:
1. 500g of the sample was weighed and the flotation cell was switched on.
2. 1200mL of water was poured initially in the flotation cell.
3. Then feed sample was added in the cell.
4. The pH was maintained at 9 by adding NaOH drop wise
5. After 5mins of conditioning the depressant was added.
6. The collector was added and the sample was conditioned for 3-5mins.
Note: collector was converted into salt and used.
8. After 2mins the air valve was opened.
9. The material was raked off after 30secs each till the 5th material and after that the 6th
froth was raked off after 3mins and were collected as froths.
10. Tailings were collected.
11. The products were dried, weighed and sent for chemical analysis.
[00032]. 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
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references to the “invention” will refer to subject matter recited in one or more, but not
necessarily all, of the claims.
[00033]. 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:
[00034]. 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.
[00035]. 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
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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).
[00036]. 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.
[00037]. 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.
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[00038]. 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.
[00039]. 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.
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WE CLAIM:
1. A novel flotation reagent for removal of silica from iron ore fines comprising:
polyhedral oligomeric silsesquioxane and amine additives.
2. The flotation reagent as claimed in claim 1, wherein the said amine additives is
octylamine.
3. The flotation reagent as claimed in claim 1, wherein the ratio of silsesquioxane to
octylamine is 1eq: 1eq
4. A process for the preparation of flotation reagent comprising the steps of:
mixing water to polyhedral oligomeric silsesquioxane in 1:1 ratio,
heating the mixture upto 50-70oC under stirring,
adding octylamine under nitrogen atmosphere,
adding water to the reactants to facilitate collection of a final compound,
subjecting the final compound to the step of purification by adding acetone
under stirring,
washing the precipitate with acetone upon filtration; and
drying the compound under vacuum.
5. The process as claimed in claim 4, wherein the said octylamine is added under nitrogen
for 3 to 4 hours.
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6. The process as claimed in claim 4, wherein the compound is dried in vacuum oven at
30oC to 40oC.
7. A process for removal of silica from iron ore fines comprising:
adding water to the iron ore fines in a flotation cell,
maintaining the pH at 8-9.5 by adding dispersant followed by conditioning,
adding depressant followed by adding polyhedral oligomeric silsesquioxane and
amine additives as collector followed by conditioning
collecting the material in the form of froth.
8. The process as claimed in claim 7, wherein the said collection is used in the form of
salt.
9. The process as claimed in claim 7, wherein the said depressant is causticized starch
solution.
10. The process as claimed in claim 7, wherein the conditioning after the addition of
dispersant is done for 3-5 minutes.
11. The process as claimed in claim 7, wherein the conditioning after the addition of
polyhedral oligomeric silsesquioxane and amine additives as collector is done for 3-5
minutes.