1. International Journal of Advanced Research in Engineering RESEARCH IN ENGINEERING
INTERNATIONAL JOURNAL OF ADVANCED and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
AND TECHNOLOGY (IJARET)
ISSN 0976 - 6480 (Print)
ISSN 0976 - 6499 (Online)
Volume 4, Issue 7, November - December 2013, pp. 147-155
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IJARET
©IAEME
STUDIES ON EFFECTIVENESS OF VARIOUS ION LEACHING
TECHNIQUES ON GEOLOGICAL SAMPLES
Swapnil C. Parmar1, Ankesh G. Rokad2, Arman G. Rokad3, Dr. Vishal S. Makadia4*
1,2,3,4
Petrography and Mineral Chemistry Laboratory, GMRDS,
Block No: 15, Dr. Jivraj Mehta Bhavan, Gandhinagar – 382 010. Gujarat, INDIA.
ABSTRACT
Leaching of ions from geological samples was carried out by various economically viable
methods. Results were compared to evaluate each method in aspects of creating state of art with high
yield and economic viability. Study was done on sediments and mica schist from Gujarat state of
India. Results show that calcination and boiling water treatment is more effective for K2O leaching
while more or less other ions get leached by Acid treatment. Some fruitful conclusions came into
focus that certain ions like Mg, Cu, Zn and Sr etc. gets released by calcination treatment.
Key Words: Chemical leaching, Ions extraction, Calcination, Sediments, Soil, Mica Schist.
1. INTRODUCTION
Chemical leaching of the ions from geological materials is significant issue for economic and
social point of view. Nature has enriched certain region with wealth of minerals. While other regions
or countries do not contain such valuable geographic formations resulting in big burden on fiscal
balance and foreign currency because of essential import of such minerals. These countries have to
look towards alternates like low grade minerals or ores having inferior amount of minerals. Chemical
leaching is most popular technique when concentration is less in ore. Such minerals like Potash,
Titanium Oxide, Vanadium (V) Oxide and Rare Earth Elements are back bone of the developing
countries economy. Many of these minerals are present in soil and sediments in various proportions.
Detailed study and Development of economically feasible technique is demand of market from long
time.
Chemical leaching of metallic, non-metallic and metalloid ions from various geological
materials is most promising method in resent time.[1-4]Chemical leaching treatment on geological
materials are also important for recovery of metallic ions and removal of polluting ions for
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2. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
environmental aspects.[5-9] Present study has been carried out to study effect of various treatments
on leaching process of ions from sediments and mica schist. Study was carried out in five different
aspects namely (a) Potash leaching, (b) Titanium Oxide leaching, (c) Vanadium(V) Oxide leaching,
(d) Trace ions leaching for facets of removal of polluting ions and (e)Other major ion oxides.
2. EXPERIMENTAL
2.1. Materials
Soil Sediment samples were collected from various sites of Kutchh region of Gujarat State,
India. Soil Sediments were collected from 50 to 200 cm depth by avoiding over burden
contamination. Special care was taken to avoid organic contamination of tree routs. Wooden tools
were used for digging out samples instead of tools of metals to eliminate impurities of metals.
Samples were collected from non agriculture land to eliminate contaminations from fertilizers and
pesticides. Samples from 50 to 200 cm depth was equally mixed and de-lumped by wooden hammer
and wooden mortar pastel. Mica schist sample was collected from Dahod of Gujarat State, India.
Each sample was crushed and ground up to -200 mesh size by Planetary Ball Mill. Three sediments
and one Mica Schist were taken for present study and Abbreviated as KS-A1, KS-A2 and KS-A3 for
sediments while MS-GS1 for Mica schist. All Chemicals used in this research were AR grade
obtained from Merck S. P. Ltd. and used as received.
(i)
Boiling Water Solubility
Each sample were treated with boiling water by adding 10g sample with 400ml water in
500ml beaker followed by stirring by glass rod to ensure proper mixture. Beaker was kept on hot
plate and heated at boiling temperature for 1 hours. Mixture was cooled and filtered. Residues were
washed by 500ml distilled water. Residues were dried and collected for further analysis.
(ii)
Calcination and Boiling Water Solubility
15g samples were taken in porcelain dish and calcined at 1000oC in muffle furnace for 1hr.
Calcined samples were found reddish brown in color and partially fused. Sample bits were ground
and crushed gently by mortar and pestle. Fine ground sample was collected. Out of that 10g samples
were treated by boiling water as mentioned in above procedure (i).
(iii) Acid Solubility
10g samples were taken in 500ml beaker and mixed with 400ml 0.1N HCl gently by glass
rod. Mixtures were heated on hot plate at boiling temperature for 1 hour. Beakers were removed
from hot plate and cooled. Mixtures were filtered and residues were washed with 500ml distilled
water. Residues were dried and collected for further analysis.
2.2. Characterization
All samples were characterized on XRF instrument (PANalytical, Advance AXIOS).
Analyses were carried out by making press pallet of treated and non treated samples by applying
200KN force. Pallets were analyzed in standard conditions with SUPER Q software. Instrument was
calibrated by Certified Reference materials/ Standard Reference Materials of Soil/ Sediments namely
GSD 2a to 8a, GSD 9 to 12, GSS 3 to 11, STSD 1, 2 and 4, SARM 42.
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3. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
3. RESULTS AND DISCUSSION
Initially samples were analyzed by XRF for determination of chemical composition of raw
samples. Treated samples were dried and again analyzed by identical procedure as mentioned earlier
in experimental section. Results were compared and calculated to determine leaching ability of each
technique in percentage concentration of initial mineral concentrations. An important parameter that
determines the effectiveness of a leaching process was calculated by following formula,[10]
େ୮ିେ୰
Percentage (%) of element leached =
େ୮
ൈ 100
Where, Cp= Initial element concentration in precursor
Cr = Element concentration in residue
Analysis and comparisons were done in following aspects,
K2O Leaching
Serious focus was given to Potash leaching because sediments in Kutchh were found
potassium reach during XRF analysis (approx. 2.5 – 3 wt. %). Simultaneously it is well
known that Mica Schist is also high potash bearing mineral because of its Granatic/Feldspar
rock origin. Results gained were compared by bar chart as shown in Figure 1.
% Leaching
(i)
Samples Name
Boiling Water Treated
Calcination and Boiling Water Treated
Figure 1.K2O leaching by various methods
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Acid Treated

4. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
Potash leaching study shows that in each sample including sediments and mica schist
is strongly bound and it is not leachable easily by boiling water. Hence it concluded that
easily mobilizable fraction of potassium ion is negligible in all samples. While oxide bound
fraction is quit higher in all samples. This results in highly release of potassium ion after
calcination. High temperature treatment causes dissociation of major carbonate and some
oxide bonds.
Meanwhile it is also noticed that acid treatment is also leaching more fraction of
potassium that one in boiling water treatment but less fraction that one of Calcination
treatment. It can be justified by assuming that each sample contains oxide bonds which are
less stable in high temperature. Acid dissociative bond like carbonate bond etc. are holding
some of the total fraction but not all. Major fraction is well known residual fraction[11] that
is crystalline bound ions. Results show that calcination treatment is more effective and
highest yielding method amongst all.
V2O5Leaching
Leaching behavior of Vanadium(IV) Oxide was also studied and results were compared
as shown in Figure 2. Results show that V2O5 leaching behavior is quit similar with each
other in the case of sediments. Apart from behavior shown in first case of Potassium ion;
Vanadium ion shows little different behavior indicating its different form of bounding present
in minerals.
% Leaching
(ii)
Samples Name
Boiling Water Treated
Calcination and Boiling Water Treated
Figure 2.V2O5 leaching by various methods
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Acid Treated

5. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
Results show that significant amount of free mobilized ion fraction is present in
sediments while the same is not present in mica schist. In the case of sediments Calcination
increases leaching ability up to 18-20 % and acid treatment increases the same up to 35-45 %.
But surprisingly mica schist shows different behavior by increasing leachable ions up to 6065% in acid treatment. Considering importance of Vanadium metal in present market mica
shiest can immerge as potential alternate of mining and acid treatment is the method yielding
most fruitful result in case of Vanadium ion.
TiO2 Leaching
Present study highlights important feature of TiO2 leaching by various techniques.
Study shows that there is small difference between leached ions by boiling water and
calcination in the case of sediments and it varies between 10-20 wt. %. While in the case of
mica schist negligible amount was leached by boiling water and calcination process. Among
with that it is noticed that in all samples acid treatment is most promising and high yielding
process. Acid treatment leaches up to 80-90 wt % in sediments and approx. 50 wt % in Mica
Schist.
It is also noticed that easily mobilizable fraction of Titanium ion is significantly present
in sediments while it is nearly absent in Mica schist. Bound fraction of ions in thermally
dissociative bond is small as compared to Potassium ions. While Acid leachable fraction of
ions bound with various metal oxides is very high in all samples.
% Leaching
(iii)
Samples Name
Boiling Water Treated
Calcination and Boiling Water Treated
Figure 3.TiO2 leaching by various methods
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Acid Treated

6. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
% Leaching
Acid Solubility
Fe2O3
MgO
P2O5
MnO
% Leaching
Calcination and Boiling Water Solubility
Fe2O3
MgO
P2O5
MnO
% Leaching
Boiling Water Solubility
Fe2O3
KS-A1
MgO
P2O5
KS-A2
KS-A3
MnO
GS-MS1
Figure 4. Some Major Oxides leaching behavior of different samples by various methods where
samples are as follow
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7. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
% Leaching
Acid Solubility
% Leaching
Calcination and Boiling Water Solubility
% Leaching
Boiling Water Solubility
KS-A1
KS-A2
KS-A3
GS-MS1
Figure 5. Some Trace Ions leaching behavior of different samples by various methods where
samples are as follow
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8. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME
Results clearly show that all samples are containing significant amount of MgO in form of
easily mobilizable fraction. This can be seen in Figure 4 where boiling water leaching of MgO is
between 6 to 8.5 wt %. While none of the other major oxide is in easily mobilizable fraction. Upon
Calcination changes in crystal form occurs. This complex changes includes breaking of some
existing bonds and formation of some new bonds resulting in release of certain ions and trapping of
some other ions. As shown in Figure 4MgO becomes more mobilized in case of Mica Schist but it
becomes trapped in sediments samples after thermal treatment. In contrast of that P2O5 is more
mobilized in sediments after heat treatment and remains unchanged in mica schist. Fe2O3 becomes
minute mobilized in mica schist after heat treatment.
In addition to that all major oxides become highly mobilized and leachable in acid treatment.
This can be because of presence of acid soluble oxide cages in crystal lattice in all samples. All
sediments and mica schist samples are containing oxides bonding that are only dissociative by acids
and not by heat treatment any more.
Along with major oxides, minor ions also encountered in present study. Figure 5 shows
results of trace element’s leaching behavior. It is significantly noticed that Mica Schist is containing
easily mobilizable fraction of Sr which is nearly 14 wt % While Pb up to 1 wt% but none of the other
ions get leached in boiling water. It indicates that all ions are bound in crystal structure and no free
ions present in any sample except Sr and Pb in Mica Schist.
Thermal treatment releases Cu and Pb ions in sediments while Cu, Ni, Zn, Pb and Sr gets
released up to 35 wt % by thermal treatment. Again here acid treatment releases very high amount of
ions nearly 60 to 90 wt % for Cu, Ni, Co, Zn and Pb in all samples and Sr in Mica Schist. Other ions
are assumed as trapped in highly bound in strong silica matrix.
4. CONCLUSION
Sediments contain small fraction of easily mobilizable fraction which gets extracted by
boiling water
Calcination is promising treatment for all kind of geological samples for increase in
extraction ability of boiling water
K2O leaching study indicated that calcination is highest yielding method amongst all while in
the case of other ions Acid extraction is highest yielding
Along with that certain ions like Sr is leachable in boiling water in mica schist while none of
other trace ions are leachable in boiling water. But calcination makes some of the trace ions
leachable in boiling water
Acid extraction is high yielding procedure that is why this procedure is more promising for
extraction. But where economy and environmental issues are important then calcination is
also promising alternate.
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