FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; Rule 13)
A solvent composition and a process for lithium extraction from batteries
Fonsmet material Pvt. Ltd.
Office No. 1902, Building -Fairmount
Plot No.4/5/6, Sector 17, Sanpada-400705, Maharashtra, India
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
FIELD
The present disclosure relates to the field of chemical recovery from lithium batteries.
Particularly, it relates to a solvent composition and a process for lithium extraction
from the batteries. The lithium obtained is of battery grade.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have
the meaning as set forth below, except to the extent that the context in which they are
used indicates otherwise.
Lithium batteries refer to the batteries essentially consisting of the lithium
compound along with other organic substances; and
D2EHPA (Di (2-ethylhexyl) phosphoric acid) refers to diester of phosphoric acid
for solvent extraction.
BACKGROUND
The background information herein below relates to the present disclosure but is not
necessarily prior art.
Lithium batteries are the type of rechargeable batteries wherein the energy is stored
by the reversible intercalation of Li+ ions, so also referred to as Li-ion batteries. The
electrolyte carries positively charged lithium ions from anode to cathode. The
movement of the lithium ions creates free electrons in the anode which creates a
charge at the positive current collector. While the battery is discharging and providing
an electric current, the anode releases lithium ions to the cathode, generating a flow
of electrons from one side to the other. When plugging in the device, the opposite
happens and the lithium ions are released by the cathode and received by the anode.
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Reference is made to US8715865B2 for non-aqueous electrolytic solutions and
electrochemical cells, including Li-ion batteries. These Lithium-Ion batteries provides
the highest energy density with a large charge cycle, making it the fastest growing
and most promising battery for numerous applications. Reference is made to “Et. al
Min G., in smart clothes and wearable Technology, 2009” pertaining to the Power
supply sources for smart textiles. However, the consumption and utility of these
batteries generates enormous waste in the process of its disposal. Thus, a need exists
to recycle the battery and the chemical materials therein, to minimize the environment
hazards.
Conventional, recycling of lithium battery is done by acid treatment and by hydrometallurgical route. In this regard, reference is made to CN113322380B and
EP2813587B1, wherein the strong chemicals are used, adding more burden to the
environment. However, chemical recovery from the known methods is also very low.
In few of these known processes, the Li recovery may not be targeted, while elements
such as Co, Cu and Ni are recovered as oxides or hydroxides. Moreover, the purity of
the recovered chemical material is not optimal for reuse and their subsequent
applications.
There is, therefore, felt a need that mitigates the drawbacks mentioned hereinabove or
at least provide a suitable alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein
satisfies, are as follows:
An object of the present disclosure is to provide a solvent composition and a process
for lithium extraction from batteries.
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An object of the present disclosure is to provide a solvent composition and a process
for efficient and high purity lithium extraction from the batteries to be used back in
battery manufacturing.
Another object of the present disclosure is to provide a solvent composition
comprising an organophosphorus compound, a fatty acid and a diluent.
Another object of the present disclosure is to provide a process of obtaining lithium
with high purity from the lithium batteries.
Still another object of the present disclosure is to provide a process of sequential
chemical recovery of aluminium, manganese, cobalt, nickel and lithium from the
batteries.
Yet another object of the present disclosure is to provide an efficient process to obtain
lithium as lithium carbonate (Li₂CO) and lithium hydroxide (LiOH) with high purity.
Yet another object of the present disclosure is to provide a process based on solvent
composition comprising D2EHPA, 2-octanol, Tributyl phosphate and kerosene for
the chemical recovery from batteries.
Still another object of the present disclosure is to provide a process comprising the
steps of size reduction, leaching, precipitation and solvent extraction to obtain
chemical substances from the lithium batteries.
An object of the present disclosure is to ameliorate one or more problems of the
background or to at least provide a useful alternative.
Other objects and advantages of the present disclosure will be more apparent from the
following description, which is not intended to limit the scope of the present
disclosure.
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SUMMARY
The present disclosure relates to a solvent composition and a process for lithium
extraction from batteries.
The solvent composition for lithium extraction from batteries comprises
organophosphorus compounds consisting of at least one selected from Di (2-
ethylhexyl) phosphoric acid, and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl
ester in a range of 15 to 50% (v/v); and tributyl phosphate (TBP) in a range of 2
to10% (v/v). The solvent composition further comprises at least one fatty alcohol
selected from 2-octanol and iso decanol in a range of 2 to10% (v/v); and at least one
diluent selected from kerosene, and high paraffin oil in a range of 55 to 80% (v/v).
The solvent composition comprises organophosphorus compound selected from Di
(2-ethylhexyl) phosphoric acid is in an amount of 20% (v/v); and the tributyl
phosphate (TBP) is in an amount of 5% (v/v); the fatty acid selected from 2-octanol is
in an amount of 5% (v/v); and the diluent selected from kerosene in an amount of
70% (v/v).
The solvent composition comprises organophosphorus compound, selected from 2-
ethylhexyl phosphonic acid mono-2-ethylhexyl ester is in an amount of 30% (v/v);
the tributyl phosphate (TBP) is in an amount of 7.5 % (v/v); the fatty acid selected
from 2 octanol is in an amount of 7.5(v/v); and the diluent selected from kerosene in
an amount of 55% (v/v).
The process for lithium extraction comprising the steps of miling black mass sourced
from batteries to obtain black mass having particle size less than 60 micron, followed
by mixing water with the black mass particles in a ratio of 1:3.5 to obtain slurry.
Further, the slurry is treated with at least one leaching agent in predetermined
conditions to obtain leach liquor. Water is added to the leach liquor to obtain a first
solution. The first solution is treated at a pH optimized in the range of 3.6 to 4.0 using
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a base for a time period in the range of 2 to 4 hours to obtain iron precipitates and a
filtrate. The filtrate free from iron is water washed to obtain a second solution,
followed by treating the second solution with an acid to obtain a first feed having a
pH in the range of 2.4 to 3.4. The first feed is solvent extracted using the solvent
composition, to sequentially obtain lithium as lithium hydroxide.
The base is selected from ammonia (25%) for pH in the range of 3.6 to 4.0 to
precipitate iron and to minimize elemental losses in the filtrate. The pH in the range
of 3.6 to 4.0 precipitates iron and minimizes elemental losses in the filtrate. At pH of
3.6 to 4.0, 10% aluminium is co precipitated along with iron and the co precipitation
of lithium is avoided. If more aluminium is precipitates then there is loss of lithium
due to precipitation of lithium aluminate with Al: Li in range of 3:1 to 5:1.
The lithium hydroxide, is carbonated in the presence of CO2 to obtain precipitates,
followed by drying at a temperature in the range of 180 to 220o C to obtain lithium
carbonate (Li2CO3) having a purity of 99.5%. Description:BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The solvent composition and the process of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates the effect of pH on the precipitation of elements in accordance with present disclosure;
Figure 2 illustrates the effect of pH on the extraction of aluminum, manganese, cobalt, nickel and lithium; in single stage experiments;
The results in Figure 2 indicates that in the solvent composition A, the synergistic effect extracts manganese and subsequently lower lithium extraction, thus eliminating lithium losses with the aluminium in this stage. The results provide the extractions effeciencies of elements at pH eof 1.97 for solvent composition A (20% D2EHPA+ 5%; 2 Octanol; 5% TBP; and 70 % kerosense). The solvent composition A comprising TBP, the manganese extraction incresed from 14.45% to 47.58% and the Lithium extraction decreased from 12.4% to 0.2%, in this stage.
Figure 3: illustrates the comparison of the extractions effeciencies of elements at pH eq of 1.97 using solvent composition C (20% D2EHPA+ 10% 2 Octanol +70% kerosense). The results indicate that in the absence of TBP, the manganese extraction is 14% and lithium extraction is 12.4%.
Figure 4 illustrates the effect of pH on extraction of elements Mn Co, Li and Ni for 20% D2EHPA + 5% 2 octanol + 5% TBP + 70% rolex 57 (kerosense) . The results in Figure 4 indicate that in the solvent composition A, the synergistic effect extracts Mn Co, Li and Ni.
Figure 5 illustrates the extraction of manganese by varying the O/A (Organic/aqueous) ratio;
Figure 6 illustrates the extractions of elements in the organic phase in six stage counter current; and
Figure 7 illustrates the effect of organic/aqueous phase (O/A) ratio on extraction of Al.
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
When an element is referred to as being "mounted on," “engaged to,” "connected to," or "coupled to" another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc.,should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc. when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Terms such as “inner,” “outer,” "beneath," "below," "lower," "above," "upper," and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
The lithium-Ion battery provides the highest energy density with a large charge cycle, making it the fastest growing and most promising battery for numerous applications. However, it generates enormous waste in the process of its dispose. Thus, a need exists to recycle the chemical materials to minimize the environment hazards. Conventionally, the recycling of lithium battery is done by acid treatment and by hydro-metallurgical route. The use of strong chemicals even adds more burden to the environment. However, the recovery of chemicals is also low. Moreover, the purity of the recovered chemical material is not optimal for reuse. In most of the know processes, the Li recovery may not be targeted while Co, Cu and Ni are recovered as oxides or hydroxides or sulfates
Di- (2-ethylhexyl) Phosphoric acid is an organo phosphorous compound is used in solvent extraction of metals due to its cation exchanging property. D2EHPA exists as dimer and if used as it is, the extractability is very low. The dimer needs to be broken into monomers to increase the extraction capacity which is done by sodium as a saponification agent. However, sodium is detrimental impurity to battery grade lithium carbonate or hydroxide, any foreign inclusion of sodium has to be strictly avoided. Thus, there is a need to provide a solution to the above mentioned problem, or least provides a suitable alternative.
The plant for the lithium extraction currently provides lower recoveries of 75 to 85% and has low purities of 97% and thus cannot be used back for battery applications. The lithium obtained by the conventional approached fails to provide battery grade lithium.
Therefore, the present disclosure provides a solvent composition and a process for lithium extraction from batteries.
In an aspect, the present disclosure provides a solvent composition for lithium extraction from batteries.
In an embodiment, the solvent composition comprises organophosphorus compounds consisting of at least one selected from Di(2-ethylhexyl) phosphoric acid, and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester in a range of 15 to 50% (v/v); and tributyl phosphate (TBP) in a range of 2 to10% (v/v); at least one fatty alcohol selected from 2-octanol and iso decanol in a range of 2 to10% (v/v); and at least one diluent selected from kerosene, and high paraffin oil in a range of 55 to 80% (v/v).
The paraffin oil is ROLEX 57. The 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester is Ionquest 801.
In an exemplary embodiment, the solvent composition comprises the organophosphorus compounds are selected from Di (2-ethylhexyl) phosphoric acid is in an amount of 20% v/v and tributyl phosphate (TBP) is in an amount of 5% v/v; the fatty acid selected from 2-octanol is in an amount of 5% v/v; and the diluent selected from kerosene in an amount of 70 % v/v. (hereinafter referred to as composition A)
In an exemplary embodiment, the solvent composition comprises the organophosphorus compounds are selected from 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester is in an amount of 30% v/v and the tributyl phosphate (TBP) is in an amount of 7.5 % v/v; the fatty acid selected from 2 octanol is in an amount of 7.5 v/v; and the kerosene in an amount of 55% v/v. (hereinafter referred to as composition B)
In another embodiment, the solvent composition comprises 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester is in an amount of 30% (v/v); 2 octanol is in an amount of 15% (v/v); and the kerosene in an amount of 55 %( v/v). There is no special effect of TBP for cobalt extraction.
In second aspect, the present disclosure provides a process for lithium extraction from batteries.
In an embodiment, the process comprises the steps of:
a. miling black mass sourced from batteries to obtain black mass having particle size less than 60 micron;
b. mixing water with the particles of black mass in a ratio of 1:3.5 to obtain slurry:
c. leaching the slurry with at least one leaching agent in predetermined conditions to obtain a leach liquor;
d. adding water to the leach liquor to obtain a first solution;
e. treating the first solution at a pH optimized in the range of 3.6 to 4.0 using a base for a time period in the range of 2 to 4 hours to obtain iron precipitates and a filtrate;
f. Water washing the filtrate free from iron to obtain a second solution, followed by treating the second solution with an acid to obtain a first feed having a pH in the range of 2.4 to 3.4; and ph is adjusted with ammonia and sulphuric acid.
g. Solvent extracting the first feed with the solvent composition, to sequentially obtain lithium.
Oxalate is then converted to lithium hydroxide by adding barium hydroxide.
Li2SO4 + Ba(OH)2 – 2 LiOH(l) + BaSO4(s)
During the solvent extraction process, the H+ in the solvent is replaced by interest cation at a favorable pH and hence the raffinate pH decreases due to transfer of H+ in the solution which then brings stripping condition for the interest cation and hence it is necessary to maintain the equilibrium pH for the efficient extractions. For controlling pH introduction of alkali or acid to maintain equilibrium pH for efficient extraction and also saponification is done.
In an embodiment, the process is described in detail.
In a first step, the black mass from the batteries is milled to obtain black mass having particle size less than 60 micron.
In an embodiment, the black mass from the batteries is ball milled for 10 to 15 hours.
In an embodiment, the black mass is obtained from batteries selected from LFP, LMO, LCO, NMC batteries.
In an embodiment, the particles of black mass are having particle size less than 60.
In an exemplary embodiment, the ball milling is done for 12 hrs to obtain 95% ball-milled black mass from the batteries.
In an embodiment, the ball-milled black mass passes through 200 mesh.
In accordance with the present disclosure, the black mass obtained from LFP, LIMO, LCO and NMC batteries is crushed in a wet ball mill for 12 hours to obtain min 95% material passing through a 200 mesh having particle size reduced to less than 60 micron.
In a second step, the water and black mass particles are mixed in a ratio of 1:3.5 to obtain slurry.
The black mass as the crushed powder in the slurry form is fed into a glass lined reactor. Further, the additional water is desired so that ratio of 1:3.5 is maintained to obtain slurry.
In a third step, leaching the slurry in predetermined conditions to obtain leach liquor.
In an embodiment, the predetermined conditions comprises a temperature in the range of 75 to 85 °C; a time period in the range of 5 to 7 hours; and at least one leaching agent selected from sulphuric acid (H2SO4), hydrogen peroxide (H2O2), and a mixture thereof.
In an exemplary embodiment, the leaching agent is a mixture of 98% H2SO4 and 30% H2O2; the temperature is in the range of 80 °C; and time period is 8 hours.
The sulphuric acid is added in 20% stoichiometric excess to achieve maximum recovery of 85 to 92%. The reductive leaching is adopted to convert CO3+ to CO2+ which is more soluble.
The optimal time for leaching is 6 hours at 80°Cto achieve 99% recovery of lithium, cobalt, nickel, manganese and aluminium. Then solids and liquid separation is achieved through use of a filter press.
In a fourth step, water is added to the leach liquor to obtain a first solution.
The residue obtained is water washed with solid: liquid ratio of 1:1.5 to remove maximum elements trapped with moisture.
In an embodiment, the first solution comprises elements selected from Al, Co, Cu, Li, Mn, Ni and Fe with water.
In an exemplary embodiment, the first solution comprises Al of 17.29glp, Co of 51.3 glp, Cu of 0.2 glp, Li of 8.34glp, Mn of 21.47 glp, Ni of 9.8 glp and Fe of 0.66glp.
In an embodiment, the composition of the first solution is summarized as table 1:
Element Al Co Cu Fe Li Mg Mn Ni Na
Amounts in glp 17.29 51.3 0.2 0.66 8.34 0.22 21.47 9.8 0.84

The H2O2 acts as both reducing and oxidizing agent and aids in improving leaching efficiency as well as converting Fe2+ to Fe3+ which is beneficial for the subsequent solvent extraction.
Fe3+ precipitates at pH 3.5 to 4 hence no interference in solvent extraction
The reaction governing ferrous to ferric conversion is as follows;
2Fe2+ + H2O2 + 2H+? 2Fe3+ +2 H2O
The crushed black mass has up to 14 wt% metallic aluminium. When the sulphuric acid reacts with metallic aluminium nascent hydrogen is released that creates reducing atmosphere.
2Al+ 3H2SO4------- > Al2(SO4)3 + 6H(gas)
In accordance with the present disclosure, for achieving the lithium and cobalt recovery of more than 98%hydrogen peroxide is added in 20%excess of the stoichiometric quantity and after 2 hours more than 99% of lithium, cobalt, manganese, copper, nickel and aluminium is leached. The governing reaction is as below:
2 LiCoO2 + 3H2SO4 + H2O2?2CoSO4 + 2 LiSO4 + 4 H2O + O2 (g)
In traditional processes the cobalt concentration is 20 gpl max but in this invention the cobalt concentration of min. 40 gpl is maintained to avoid excess energy consumption while recovering ammonium sulfate through evaporative crystallization.
In a fifth step, the first solution is treated with a base for pH optimization for a time period in the range of 2 to 4 hours to obtain iron precipitates and a filtrate.
In an embodiment, the base in step (e) is selected ammonia (25%).
In accordance with the present disclosure, there is no alternate except for ammonia. KOH can be used but same problem/drawback as sodium because potassium is also a detrimental impurity for battery grade lithium carbonate
In an embodiment, optimizing pH is in the range of 3.6 to 4.0 to improve iron precipitation and to minimize elemental losses in the filtrate, particularly Al co-precipitation which incurs lithium losses due to precipitation of lithium aluminate.
The first solution has most of the iron is in ferric form. The base (25% ammonia) is added slowly to the first solution to adjust the pH between 3.6 to 4. Initially on addition of ammonia precipitate forms which gets dissolved after sometime till pH 3.6 after which the precipitate remains un-dissolved. After adjusting pH between 3.6 to 4, a time of 3 hours is given for stabilization after which the precipitate is filtered and water washed to obtain a filtrate free of iron. The Iron precipitation efficiency of 96 to 99% is thus achieved with aluminium co precipitation of 10% maximum. At this stage there is no loss of other elements like lithium, cobalt, manganese etc a
In accordance with the present disclosure, the pH 4 provides no losses of other interest elements like lithium, cobalt, nickel, manganese etc, except for aluminium loss which is maximum 10 %. If the pH is increased above 4 and between 4.2 to 4.5 almost 30 to 40% aluminium is precipitated. Along with aluminium, lithium is also precipitated in the form of lithium aluminate. The loss of lithium is between 13 to 20% which is due to precipitation of lithium aluminate complex with Al: Li ratio varying between 1:3.5 to 1:4.5. The precipitation efficiencies vs. pH graph are shown in Fig. 1.
The base is selected from ammonia (25%), for pH in the range of 3.6 to 4.0 to precipitate iron and to minimize elemental losses in the filtrate, wherein at the pH is in the range of 3.6 to 4.0, 10% aluminum is co precipitated along with iron and the co precipitation of lithium is avoided.
The increased amount of aluminum precipitates results in the loss of lithium due to precipitation of lithium aluminate with Al:Li in range of 3:1 to 5:1
In a sixth step, the filtrate free from iron is added with water for water washing of iron precipitate to obtain a second solution, followed by treating the second solution with an acid to obtain a first feed having a pH in the range of 2.4 to 3.4
In an embodiment, the pH in the sixth step is in the range of 2.8 to 3.4 using H2SO4 for leaching in step (iii).
The concentrations of the first feed are provided below as table 2:
Element Al Co Cu Fe Li Mg Mn Ni Na
Amounts in gpl 15.54 47.8 0.01 0.008 7.68 0.18 19.8 9 0.63
In a seventh step, the first feed is solvent extracted with solvent composition, to sequentially obtain lithium as lithium hydroxide.
In an embodiment, the lithium hydroxide, is carbonated in the presence of CO2 to obtain precipitates, followed by drying at a temperature in the range of 180 to 220o C to obtain lithium carbonate (Li2CO3) having a purity of 99.5%.
In an embodiment, pH in the range of 3.6 to 4.0 is to precipitate iron and to minimize elemental losses in the filtrate, particularly Al co-precipitation for the solvent extraction. The pH is in the range of 3.6 to 4.0, 10% aluminum is co precipitated along with iron and the co precipitation of lithium is avoided.
The increased amount of aluminum precipitates results in the loss of lithium due to precipitation of lithium aluminate with Al:Li in range of 3:1 to 5:1.
In an embodiment, the predetermined conditions comprise a temperature in the range of 75 to 85 °C; and a time period in the range of 5 to 7 hours.
In an embodiment, the leaching is in the presence of sulphuric acid (H2SO4), hydrogen peroxide (H202), and a mixture thereof.
In an embodiment, the base in step (e) is added to optimize the pH, wherein the base is selected from 25% ammonia.
In an embodiment, the iron precipitates in step (e) are dried at a temperature of 150 °C for 2 hours and calcined at a temperature of 800oC for 2 hours to obtain red iron oxide. The iron precipitation efficiency is up to 99%.
In an embodiment, the lithium is extracted in a sequence. In an exemplary embodiment, the lithium is extracted from first feed after extracting aluminium, manganese, cobalt, and Nickel by the solvent extraction.
In an embodiment, the solvent composition is pre-treated with 0.5 M ammonium hydroxide in a ratio of 5:1 for solvent extracting aluminium, manganese, cobalt, Nickel and the lithium in the organic phase.
D2EHPA is contacted with sodium hydroxide solution initially to achieve an ion exchange between H+ and Na+ to produce Na-D2ehpa. This Na-D2EHPA is then used to extract metals like copper, iron, cobalt etc, in this process now the ion exchange happens between Na+ and interest element (Co, Cu etc) If the extraction is limited to the degree that some Na-D2EHPA is free to react ensures that the pH equilibrium doesn’t change much and thus avoids addition of additional alkali or acid to maintain pH.
In accordance with the present invention, sodium hydroxide is not used. as sodium is a detrimental impurity. Only ammonia is used.
In an embodiment, the solvent extraction comprises the steps of the solvent extraction comprises the step of mixing a first feed with solvent composition at a pH of 2.8 to 3.4 using ammonia to maintain pH between 2 to 2.8 to achieve 99% aluminium extraction in organic phase to obtain Al raffinate, followed by adding 25% ammonia to the Al raffinate for a pH in the range of 4.00 to 4.5 to obtain a second feed. The extracted aluminum in organic phase is back extracted using 2M H2So4 solution to obtain aluminum sulfate solution.
The second feed is mixed with solvent composition at a pH of 4.2 to extract more than 99.5% manganese in the organic phase to obtain manganese raffinate which is then adjusted pH between 4.8 to 5.5 to obtain a third feed. Along with manganese Co extraction of 12.2% and Lithium co extraction of 4.5% is realised, making it necessary to scrub the extracted solvent with dilute sulphuric acid to remove lithium and cobalt from organic phase. The manganese loaded organic is then contacted with 2 M H2SO4 to obtain manganese sulfate
The third feed is mixed at pH of 4.8 with solvent composition to extract min 99% cobalt to obtain cobalt raffinate. The cobalt raffinate is then added with ammonia to adjust the pH to 5.5 to 6 to obtaina fourth feed. The cobalt loaded organic is scrubbed with sulphuric acid to remove traces of co extracted lithium and nickel followed by back extraction of cobalt with 5 M H2SO4 to obtain pure cobalt sulfate.
The fourth feed is mixed at a pH of 5.8 with solvent composition to obtain nickel extraction of more than 99.5% in organic phase to obtain nickel raffinate to obtain fifth feed. The nickel loaded organic is then scrubbed with dilute sulphuric acid to remove lithium. The nickel in loaded organic is then back extracted with 5 M H2SO4 to obtain highly pure nickel sulfate solution.
The fifth feed is mixed at a pH of 5.8 with solvent composition to extract more than 99.5% lithium in the organic phase while maintaining pH between 5 to 6 using liquor ammonia. The lithium loaded organic is then scrubbed with dilute sulphuric acid to remove co extracted ammonium ions at pH 5. The lithium in loaded organic is then back-extracted using oxalic acid to obtain highly pure lithium oxalate solution. Obtained lithium oxalate is then added with barium hydroxide, to obtain barium oxalate and lithium hydroxide.
In an embodiment, the solvent extraction comprises the steps:
• Mixing a first feed with the solvent composition A at a pH of 2.8 to extract aluminum and obtain aluminum depleted aqueous phase termed as “Al raffinate”, wherein the aluminum loaded in organic is back extracted using 2M sulphuric acid to obtain aluminium sulphate;
• adding 25% ammonia to the Al raffinate for a pH in the range of 4.00 to 4.5 to obtain a second feed;
• mixing the second feed with the solvent composition A at a pH of 4.2 to extract manganese and obtain a manganese depleted aqueous phase termed as “Manganese raffinate/third feed”, wherein the manganese loaded in organic is back extracted with 2 to 5 M sulphuric acid to obtain Mn sulphate ;
• Mixing the third feed at pH of 4.8 with solvent composition B to extract cobalt and cobalt depleted phase is termed as “Cobalt raffinate”, wherein the cobalt raffinate is then adjusted pH to 5.8 with ammonia to obtain “fourth feed” and the cobalt loaded in organic is then back extracted with 2 to 5 M sulphuric acid to obtain cobalt sulphate ;
• Mixing the fourth feed at a pH of 5.8 with solvent composition B to extract nickel and nickel depleted aqueous phase termed as “nickel raffinate/ fifth feed”, wherein the nickel loaded in organic is then back extracted with 2 to 5 M sulphuric acid;
• Mixing the fifth feed at a pH of 5.8 with solvent composition A to extract lithium and obtain lithium depleted aqueous phase termed as “Raffinate”, wherein the lithium loaded in organic phase is then back extracted with 0.5 M to 1 M oxalic acid solution to obtain lithium oxalate solution; and
• obtaining highly pure barium oxalate solution treated with barium hydroxide, to obtain barium oxalate precipitate and lithium hydroxide,

wherein the solvent composition is pre-treated with 0.5 M ammonium hydroxide in a ratio of 5:1 for solvent extracting aluminium, manganese, cobalt, Nickel and the lithium in the organic phase.

In an embodiment, the pH of first feed is 2.5 to 3.5. In an exemplary embodiment, the pH is 2.8.
Aluminum is completely extracted in 6 stage counter current with O/A (Organic/aqueous) ratio of 2:1 to 4:1 and preferably 2.5:1 and maintaining pH at 2.6 to 2.8. the pH can be adjusted by addition of ammonia and sulfuric acid. The aluminum depleted aqueous phase is referred to as “aluminum raffinate”. The effect of pH on extraction efficiency of aluminum, manganese, cobalt, nickel, lithium in 6 stage counter current is shown in figure 6.
The experimental results of pH dependent extractions (shown as in figure 6) provide the pH range of 2.8 to 3.2 is ideal for aluminum extraction with less than 0.5% co extraction of lithium. So pH range of 2.8 to 3.2 was adopted for further experiments.
At the concentration in the present inventions O/A ratio of 1:1 was not sufficient for complete extraction of aluminum hence experiments were performed to analyze the effect of O/A ratio of extraction efficiency of aluminum and results are as shown in figure 7.
According to experimental data displayed in figure 7 the extraction of alumnium increases with increasing O/A ratio and it reaches a plateau above O/A ratio of 2.5:1. At O/A ratio of 2.5:1 around 75% of aluminum was extracted in single stage and complete extraction was achieved in 6 stage counter current.
In nickel and cobalt processing, it is a general procedure to precipitate out aluminum or leaching is done where pH is maintained at 3 to minimize aluminum leaching as considered as low value product. However, pH-based leaching of black mass results in low recoveries of lithium, cobalt and nickel that are high value products.
Therefore, if aluminium has to be precipitated then the pH has to be at least 5 to 6 to precipitate more than 70% aluminum but in precipitation of aluminum from black mass lithium is co precipitated in the form of lithium aluminate and cobalt is also lost to co precipitation thus loss of high value products. This is in accordance with the present disclosure.
In an exemplary embodiment, the iron is removed, which was detrimental to solvent extraction with D2EHPA as it strongly binds to the solvent and is difficult to strip unless high concentration of acid (10 M HCl or 6 M H2SO4) is used which increases the cost of production.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENT:
Example 1: The solvent composition in accordance with the present disclosure.

Table 3:
S. No Components
Composition A
Composition B Composition C
(Comparative for composition A) Composition D
(Comparative for composition B)
1. Organ phosphorus compounds Di(2-ethylhexyl)phosphoric acid
(20% v/v) 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester
(30% v/v) Di(2-ethylhexyl)phosphoric acid
(20% v/v) 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester
(30% v/v)
Tributyl phosphate (TBP)
(5% v/v) Tributyl phosphate (TBP)
(7.5 % v/v)
………
………
2. Fatty alcohol 2-octanol
(5%v/v) 2 octanol
(7.5% v/v) 2 octanol
(10% v/v) 2 octanol
15%(v/v)
3. Diluent Kerosene
(70% v/v) Kerosene
(55% v/v) Kerosene
(70% v/v) Kerosene
(55% v/v)

The compositions in Table 3 above, provides that the TBP in composition A and B have an advantage of higher dipole moment and hence the third phase/crud formation is avoided at optimized conditions. Further, the effect of TBP percentage was studied on the settling time, third phase formation and extractions of nickel and cobalt.
Effect of TBP concentration on physical characteristic of the organic phase is tabulated in table 4.

Table 4. Effect of TBP concentration on physical characteristics of organic phase-
Organic Composition Co,Nigpl
In Feed Settling time Co, Ni
Organic gpl. pH eq.
30%(v/v) Ionquest 801 +15% (v/v) 2 octanol + 55% (v/v) kerosene
Co – 39.34
Ni – 6.83 2 min Co = 13.2 gpl
Ni = 0.54 gpl
- Clear Organic Phase
- Third phase Formation
- very good Separation time 4.9
30%(v/v) Ionquest 801 +11% (v/v) 2 octanol+4%(v/v) TBP+ 55% (v/v) kerosene
Co – 39.34
Ni – 6.83 2 min Co = 13.4 gpl
Ni = 0.6 gpl
- Clear organic Phase
- Third phase formed
- Very good separation time 5.2
30%(v/v) Ionquest 801 +8% (v/v) 2 octanol+7%(v/v) TBP+ 55% (v/v) kerosene
Co – 39.34
Ni – 6.83 2.5 min Co = 12.8 gpl
Ni = 1 gpl
- Clear Organic phase
- No third phase formation
- Fair separation time 4.9
30%(v/v) Ionquest 801 +7% (v/v) 2 octanol+8%(v/v) TBP+ 55% (v/v) kerosene Co – 39.34
Ni – 6.83 4 min Co = 12.8 gpl
Ni = 1.3 gpl
- Clear Organic phase
- No third phase formed
- Fair separation time 4.8
30%(v/v) Ionquest 801 +11% (v/v) 2 octanol+11%(v/v) TBP+ 55% (v/v) kerosene Co – 39.34
Ni – 6.83 10 min Co = 12.1 gpl
Ni = 1.8 gpl
- Clear Organic phase
- No third phase formed
- Separation time is more. 4.8
30%(v/v) Ionquest 801 +15%(v/v) TBP+ 55% (v/v) kerosene
Co – 39.34
Ni – 6.83 22 min Co = 13.2 gpl
Ni = 2.3 gpl
- Clear Organic phase
- No third phase formed
- Separation time is more. 5.1

From the experimental results tabulated in table 4, it was found that as TBP concentration increases there is little effect on cobalt extraction but the nickel extraction increases from 14% to 28%. Considering the physical characteristics and separation of cobalt and nickel a composition of “Composition B” of 30 %( v/v) Ionquest 801 + 7.5 %( v/v) 2 octanol +7.5 %( v/v) TBP + 55 %( v/v) Kerosene was fixed for further experiments.
At O/A ratio of 1.8:1 to 2.5:1 and preferably 2:1 in a 6 stage counter current all cobalt is extracted with co-extraction of nickel (18%) and lithium (10%).
Particulars of the experimental pilot trials (O/A = 2/1, pH eq = 4.8, 6 stage counter current)
Table 5:
Elements Co -Feed (GPL) Distribution ratio
(D)
Separation factor
(ß)
Co 39.34 1638.33
Li 6.32 0.054 ßCo/Li = 30018.49
Ni 6.83 0.11 ßCo/Ni = 14942.45
Total Organic GPL = 20.65 gpl

To obtain highly pure cobalt stream a 4 stage scrubbing is performed with Co-Feed from next batch at O/A of 25:1. In this scrubbing stage, the co extracted nickel and lithium is stripped from the loaded organic and cobalt is loaded giving the Co – loaded organic (Co – 20 to 22 gpl, Ni – 0.01 gpl, Li – 0.01 gpl). The aqueous phase obtained after cobalt extraction is referred as “co-raffinate”.
The cobalt loaded organic is then stripped with 2 to 5 M sulfuric acid to obtain a highly pure and concentrated stream of cobalt sulfate containing 80 to 90 gpl Cobalt concentration which is then crystallized at density of 1.2 to 1.25 g/cc obtaining best quality of cobalt sulfate with shiny crystals.
Example 2: A process for lithium extraction in accordance with the present disclosur1 kg of black mass was obtained from the batteries, and was ball milled for 12 hours to obtain particles of black mass with 200 mesh size. Further, it was mixed with water in a ratio of 1: 3.5 to obtain slurry. The slurry was treated with 640 ml of 98% H2SO4 and 5% (V/V) of 30% H2O2, followed by adding 1.5 lit. water to obtain a first solution. The first solution was treated with 210 ml .ammonia liquor (25%) for pH of 3.6 for 3 hrs to obtain iron precipitates and a filtrate. The separated iron free filtrate was water washed and then treated with 98% H2SO4 to obtain a first feed having a pH in the range of 2.4. The first feed is solvent extracted with the solvent composition (A and B) in accordance with present disclosure, to sequentially obtain lithium hydroxide.
The lithium hydroxide, is carbonated in the presence of CO2 to obtain precipitates, followed by drying at a temperature in the range of 200o C to obtain lithium carbonate (Li2CO3) having a purity of 99.5%.
Example 3: A process for lithium extraction in accordance with the present disclosure
1 kg of black mass was obtained from the batteries, and was ball milled for 12 hours to obtain particles of black mass with 200 mesh size. Further, it was mixed with water in a ratio of 1: 3.5 to obtain slurry. The slurry was treated with 640 ml 98% H2SO4, followed by adding 1.5 lit water to obtain a first solution. The first solution was treated with225ml ammonia liquor (25%) for a pH of 4.0 for 3 hrs to obtain iron precipitates and a filtrate. The separated iron free filtrate was water washed and then treated with 98% H2SO4 to obtain a first feed having a pH in the range of 3.4. The first feed is solvent extracted with the solvent composition, to sequentially obtain lithium hydroxide.
The lithium hydroxide, is carbonated in the presence of CO2 to obtain precipitates, followed by drying at a temperature in the range of 200o C to obtain lithium carbonate (Li2CO3) having a purity of 99.5%.
Example 4: Saponification of the solvent composition
Instead of sodium hydroxide for saponification 0.5 molar ammonium hydroxide at O/A ratio of 5:1 and restricting saponification degree to 46% evaluated by ammonium ions concentration difference in the raffinate. At this composition and O/A ratio there was no third phase formation the organic phase became a bit hazy but separation was excellent.
The organic regenerated “Composition A” by above process was then used to carry out solvent extraction of elements in second solution.
The saponification follows reaction
C16H35O2P + NH4OH ?C16H34O2 (NH4) P + H2O
Traditional processes use 10% (v/v) to 20% (v/v) D2EHPA for extraction of manganese. As the leach liquor in this invention is concentrated D2EHPA concentration of 20% (v/v) was kept constant and saponification degrees were varied to find the optimal degree to give clear organic and aqueous phases. The saponification degree and physical characteristics of the organic phase are given in table 6.
Table 6: Degree of saponification and physical characteristics of organic phase.
D2EHPA saponification
Degree Mixing time
(min) Settling time
(min) Physical characteristics
1) 10% 3 min 1 - Clear organic phase
- no third phase
2) 30% 3 min 1 - Clear organic phase
- no third phase
3) 40% 3 min 3 - Hazy organic phase with lot of air bubble inclusion
- taking comparatively more settling time
- no third phase
4) 50 % 3 min 20 - Precipitate observed in the organic phase
- Formation of third phase.

According to the experimental observations a saponification degree of 40 to 46%% was fixed for further processes.
Example 5: 2-octanol and Tributyl phosphate as phase modifier
Use of phase modifier to convert dimers to monomers to the maximum extent by breaking the hydrogen bonds. It was achieved by use of 2-octanol and Tributyl phosphate as phase modifier. The maximum Dimer to monomer conversion was derived from its loading capacity. The optimal composition is 20% v/v D2EHPA, 5% v/v 2-octanol, 5% v/v Tributyl Phosphate and remaining kerosene as diluent. In traditional processes 20 %( v/v) D2EHPA with 5 to 10% (v/v) isodecanol diluted in kerosene is used.
In this invention replacement of isodecanol with 2-octanol is studies as 2-octanol has a higher flash point of 265oC as against the flash point of isodecanol of 1040C, with a view to make operations safer. The effect of 2 octanol Vs isodecanol on loading capacities of aluminum is tabulated in table 7.
Table 7. Effect of 2-Octanol vs. Isodecanol on extraction of aluminum with Al = 11.97 gpl and mixing time of 3 min.
Organic composition Settling time Al loaded
Organic GPL pH eq.
20%(v/v) D2EHPA + 5% (v/v) Isodecanol + 75% (v/v) kerosene 1.5 2.8 gpl
- Organic phase is clear
- clear separation
- No third phase formed 2.8
20%(v/v) D2EHPA + 10% (v/v) Isodecanol + 70% (v/v) kerosene 2.5 2.7 gpl
- organic phase is clear
- clear separation
- No third phase formed 2.7
20%(v/v) D2EHPA + 15% (v/v) Isodecanol + 65% (v/v) kerosene 3 3.4 gpl
- Organic phase is hazy with air bubble trapped
- Clear separation
- Third phase formed
3.1
20%(v/v) D2EHPA + 20% (v/v) Isodecanol + 60% (v/v) kerosene 10 4.5 gpl
- Organic phase is hazy with air bubble trapped
- takes more time to settle
- Third phase formed. 3.2
20%(v/v) D2EHPA + 5% (v/v) 2-octanol + 75% (v/v) kerosene 1.5 2.6 gpl
- Organic phase is clear
- clear separation
- No third phase formed 2.7
20%(v/v) D2EHPA + 10% (v/v) 2-octanol + 70% (v/v) kerosene 2 2.8 gpl
- organic phase is clear
- clear separation
- No third phase formed 2.8
20%(v/v) D2EHPA + 15% (v/v) 2-octanol + 65% (v/v) kerosene 3 3.6 gpl
- Organic phase is hazy with air bubble trapped
- Clear separation
- Third phase formed
2.7
20%(v/v) D2EHPA +20% (v/v) 2-octanol + 60% (v/v) kerosene
8 4.2 gpl
- Organic phase is hazy with air bubble trapped
- takes more time to settle
- Third phase formed. 3
It is clear that there is no advantage of 2-octanol over isodecanol. The loading capacities are same and physical characteristics are also same but 2-octanol is chosen for further experiments as its flash point is higher and lower viscosity. And 2-octanol concentration of 10% (v/v) was fixed for further experiments.
Further the third phase formation is related to the dipole moment of the organic phase. So experiments were conducted with TBP as phase modifier with a view to increase the dipole moment of the organic phase but also to balance the viscosity of the organic phase hence 10% (v/v) 2-octanol was replaced by varying concentrations of TBP. Not much literature is available on solvent extraction of aluminum as it is preferred to precipitate it out. The effect on third phase formation and loading of the organic phase is tabulated in table8.
Table 8. Effect of TBP addition to organic phase –
Organic Composition Aluminum gpl
In Feed Settling time Al-loaded
Organic gpl. pH eq.
20%(v/v) D2EHPA +10% (v/v) 2-octanol + 70% (v/v) kerosene
12.74 1.5 2.68 gpl
- Clear Organic Phase
- Third phase Formation
- very good Separation time 2.8
20%(v/v) D2EHPA +2% (v/v) TBP +
8% (v/v) 2-octanol
70% (v/v) kerosene
12.74 2 min 5.2 gpl
- Clear organic Phase
- No third phase formed
- Very good separation time 3.2
20%(v/v) D2EHPA +5% (v/v) TBP +
5% (v/v) 2-octanol
70% (v/v) kerosene
12.74 10 min 5.6 gpl
- Clear Organic phase
- No third phase formation
- Fair separation time
- Maximum loading of Aluminum is found to be 8.2 gpl after which there is crud/ third phase formation 2.9
20%(v/v) D2EHPA +10% (v/v) TBP +
74% (v/v) kerosene
12.74 18 3.2 gpl
- Clear Organic phase
- Third phase formed
- Separation time is more. 3
From the experimental results tabulated 3. it was concluded that the organic “Composition A” composition of 20%(v/v) D2EHPA +5% (v/v) TBP +5% (v/v) 2-octanol 70 % (v/v) kerosene is optimum for an efficient extraction of aluminum without third phase formation and at pH of 2.8 to 3.2. As the TBP concentration was increased the settling time increased and loading capacity decreased when 5 %( v/v) TBP was used, this may be due to increased viscosity and slower kinetics. So, “Composition A” is used further for aluminum and manganese extraction.

Example 6: A process for sequential extraction of lithium, aluminium, manganese, cobalt, and nickel by the solvent extraction using the first feed and the solvent composition.
The solvent composition is pre-treated with 0.5 M ammonium hydroxide in a ratio of 5:1 for solvent extracting aluminium, manganese, cobalt, Nickel and the lithium in the organic phase.
The first feed is treated with the pre-treated solvent composition A at a pH of 2.8 to extract aluminium in organic phase while adjusting pH at 2.8 to 3.2 with ammonia and sulfuric acid. Due to addition of TBP the extraction of Manganese is favoured ad lower pH and lowering the available sites for lithium and cobalt co extraction, which in turn prevents co extraction of lithium with aluminium and hence no losses. The aluminium depleted aqueous phase is termed as “aluminium raffinate”. The aluminium in loaded organic is then back extracted using 2M sulphuric acid to obtain aluminium sulphate followed by adding 25% ammonia to the Al raffinate for a pH of 4.00 obtain a second feed.
The second feed is mixed with solvent composition at a pH of 4.2 to extract manganese in organic phase and the Manganese depleted aqueous phase is termed as “Manganese raffinate/ third feed”. The manganese loaded in the organic phase is then back extracted with 2 M sulphuric acid to obtain Mn sulphate and a third feed.
The third feed is mixed at pH of 4.8 with pre-treated solvent composition B to extract Cobalt in organic phase and cobalt depleted aqueous phase is termed as “Cobalt raffinate”. The cobalt raffinate is then added with ammonia to raise the pH to 5.8 to obtain “fourth feed”. The cobalt loaded in organic phase is then back extracted with 2 to 5 M sulphuric acid to obtain cobalt sulphate.
The fourth feed is mixed at a pH of 5.8 with solvent composition to extract nickel in organic phase and nickel depleted phase is termed as “Nickel raffinate/ Fifth feed”. The loaded nickel in organic phase is back extracted with 2 to 5 M sulphuric acid obtain nickel sulphate.
The fifth feed is mixed at a pH of 5.8 with solvent composition to extract lithium in organic phase and lithium depleted aqueous phase is termed as “Raffinate”. The lithium loaded in organic phase is back extracted with 0.5 to 1 M oxalic acid solution to obtain highly pure lithium oxalate solution. The obtained lithium oxalate is then treated with barium hydroxide, to obtain barium oxalate (precipitate) and lithium hydroxide.
The lithium hydroxide, is carbonated in the presence of CO2 to obtain precipitates, followed by drying at a temperature in the range of 200o C to obtain lithium carbonate (Li2CO3) having a purity of 99.5%.
Experiment 7: Aluminium extraction
According to experimental data displayed in figure 3 the extraction of alumnium increases with increasing O/A ratio and it reaches a plateau above O/A ratio of 2.5:1. At O/A ratio of 2.5:1 around 75% of aluminum was extracted in single stage and complete extraction was achieved in 6 stage counter current. Particulars of the experimental pilot trials (O/A = 2.5/1, pH eq = 2.8, 6 stage counter current)
Table 9
Elements Feed (GPL) Distribution ratio
(D)
Separation factor
(ß)
Al 15.54 477.75
Co 47.8 0.00168 gal/Co = 283785
Cu 0.01
Fe 0.008
Li 7.68 0.0018 ßAl/Li = 260410
Mg 0.18
Mn 19.8 0.0171 ßAl/Mn = 27888.8
Ni 9 0.024 ßAl/Ni = 19755.12
Total Organic GPL = 6.824
The aluminum loaded organic is then stripped with 2 to 5 M sulfuric acid preferably 3.5 M for complete stripping of aluminum. O/A ratio of 2:1 to 10:1 and preferably 5:1 in 4 stage counter current to obtain high concentrate of aluminum sulfate which can be crystallized to obtain aluminum sulfate.
Experiment 8: Manganese Extraction
Aluminum raffinate obtained from aluminum extraction circuit is then adjusted pH to 3.8 to 4.5 preferably at 4 to 4.2 by addition of ammonium hydroxide here in referred as “Mn- feed”. The effect of manganese extraction and separation from other cations is shown in figure 4.
As shown in figure 4. The optimal pH of 3.8 to 4.5 is best for manganese extraction and separation from other cations like cobalt, lithium and nickel. After pH 4.5, significant amount of cobalt is extracted in the organic phase without any improvement in manganese loading. Hence pH of 4.2 to 4.5 is adopted for further experiments.
At the manganese concentration in leach liquor of this invention the O/A ratio of 1:1 is not sufficient for complete extraction and hence manganese extractions with different O/A ratios were studied. The experimental data shown in figure 5 at different O/A ratios. As the O/A ratio increases the manganese extraction increases with no significant increase after O/A ratio of 2.5and hence an O/A ratio of 2:1 was selected for complete extraction of manganese in 4 stage counter current with cobalt co extraction of around 2 gpl i.e. 8.8% is realized which has to be removed and a scrubbing stage has to be incorporated.
The Manganese loaded organic (Mn – 8.89 gpl, Co – 1.99 gpl, Ni – 0.21 gpl., Li = 0.189 gpl) is then contacted with Mn- feed from next batch at O/A of 10:1 in 4 stage counter current. In this stage co extracted cobalt, nickel and lithium ions are replaced by manganese ions leaving 0.05 gpl Co, 0.002 gpl Nickel and 0.016 gpl Lithium in organic phase and total manganese loading of 11.28 gpl in the organic phase. Aqueous phase after manganese extraction is referred to as “Mn-raffinate”.
Particulars of the experimental pilot trials (O/A = 2/1, pH eq = 4.2, 4 stage counter current) –
Table 10
Elements Mn -Feed (GPL) Distribution ratio
(D)
Separation factor
(ß)
Mn 17.79 987.83
Co 45.25 0.048 ßMn/Co = 20512.19
Cu 0.01 -
Fe 0.008 -
Li 7.27 0.027 ßMn/Li = 36021.94
Mg 0.17 3.75
Al 0.012 -
Ni 7.87 0.029 ßMn/Ni = 33949.7
Total Organic GPL = 11.28 gpl
Manganese is then stripped using sulfuric acid of 3 to 5 M and preferably 4 M at an O/A ratio of 10:1 to obtain highly concentrated manganese sulfate solution. Stripping is performed in 4 stage counter current to achieve more than 98% of stripping efficiency.
Experiment 8: Cobalt Extraction –
With D2EHPA the cobalt and nickel are co extracted at any favorable pH for cobalt extraction and there is no desired separation. So, to obtain a desired separation between nickel and cobalt a solvent mixture of (30v/v% Ionquest 801, 7.5 v/v% 2 octanol, 7.5 v/v% TBP diluted in commercial kerosene) referred to as “Composition B” is used. The mixed solvent is regenerated with ammonium hydroxide as described in Reaction 5.
With ORG-2 and more than 40% saponification degree cobalt loading of 20 gpl can be obtained at optimized conditions. The pH of Mn- raffinate obtained from step 4B is then adjusted to 4.5 to 5.5 and preferably at 4.5 to 4.8 hereafter referred as “Co-feed”. The saponification reaction follows the reaction 5.
(C8H17)2HPO3 + NH4OH ? (C8H17)2(NH4) PO3 + H2O ------------ (5)
Experiment 9: Nickel Extraction
The pH of Co- raffinate obtained is adjusted to 5.5 to 7.5 and preferably at 5.8 to 6.3 hereafter referred as “Ni-feed”. At O/A ratio of 1:2 to 1:2.5 and preferably 1:2 in a 6 stage counter current all nickel is extracted with 15 to 20% co-extraction of lithium. A typical loaded organic contains (11 gpl Ni, 2 gpl Li).
To obtain highly pure Ni stream a 6 stage scrubbing is performed with Ni-Feed from next batch. In this scrubbing stage the co extracted lithium is stripped from the loaded organic and nickel is loaded giving the Ni – loaded organic (Ni – 12 to 15 gpl, Li – 0.01 gpl). The aqueous obtained after nickel loading is referred as “Lithium feed”.
The nickel loaded organic is then stripped with 2 to 5 M sulfuric acid to obtain a highly pure and concentrated stream of nickel sulfate containing 80 to 90 gpl nickel concentration which is then crystallized at density of 1.2 to 1.25 g/cc obtaining best quality of nickel sulfate with shiny crystals.
Particulars of the experimental pilot trials (O/A = 1/2, pH eq = 5.8, 6 stage counter current) –
Table 11
Elements Ni -Feed (GPL) Distribution ratio
(D)
Separation factor
(ß)
Ni 5.69 756.6
Li 5.26 0.5 ßNi/Li = 1513.33
Total Organic GPL = 13.45 gpl
Experiment 10: Lithium Extraction, Stripping and crystallization
1) Extraction: - The Lithium feed need no further pH adjustments and can be directly used for extraction. Lithium can be extracted with both compositions “A & B” but “Composition A” gives advantage of better loading capacity than Composition B. The Lithium extraction is carried out in 6 stage counter current with O/A ratio of 1:1 to 1.5:1.The lithium loaded organic has a lithium concentration of 3 to 5 gpl. As there is ammonium ions in the feed which compete with lithium and gets co extracted in “Composition A”. A 4 stage scrubbing stage is incorporated in which the Lithium feed from next batch is contacted with lithium loaded organic at O/A of 25:1 and ammonium ions are replaced by lithium ions. Thus, a pure lithium loaded organic phase is obtained. The lithium depleted aqueous phase is then neutralized to pH of 7 to 8 to obtain ammonium sulfate solution which is then crystallized to recover ammonium sulfate in crystal form.
Particulars of the experimental pilot trials (O/A = 1.2/1, pH eq = 5.8, 6 stage counter current) –
Table 12:
Elements Li -Feed (GPL) Distribution ratio
(D)

Li 5.26 65

2) Stripping - The extracted lithium is then stripped from the loaded organic using oxalic acid solution of 0.5 M to 1 M preferably 0.6 to 0.8 M to avoid excess oxalate ions in the solution. The O/A ratio of 2:1 to 2:1.2 is maintained and more than 90% lithium is stripped in 4 stage counter current with lithium concentration of 7 to 8.5 gpl in the stripped solution, here in referred to as “Li-PS”.
Organic Phase
ORG-2
Li = 3.9 gpl

O/A = 2:1

Li- Stripping

O/A = 2:1 Organic Phase
ORG-2
Li = 0.1 gpl
Aqueous Phase
Oxalate solution
0.5 to 0.8 M Aqueous Phase
Oxalate solution
Li = 7.8 gpl

3) Hydroxide conversion-
The obtained “Li-PS” has lithium concentration of 7 to 8.5 gpl. Barium hydroxide in crystal form is added in 5 % stoichiometric excess to convert lithium oxalate and ammonium oxalate to lithium hydroxide, ammonium hydroxide and barium oxalate. The solution is subjected to evaporation to achieve lithium concentration of 15 to 20 gpl, as the concentration increases the pH >11.5 are achieved. In this process the free ammonia is evaporated and can be neutralized using an acid scrubber. Solid to liquid separation is achieved through a filter press.
4) Precipitation -
Gaseous CO2 is purged from bottom of the reactor in the lithium concentrate obtained from (E3) and immediate precipitation of lithium carbonate of more than 90% is obtained which is then filtered off and dried and mother liquor is reused in the process of stripping with appropriate addition of oxalic acid.
5) Recovery of barium –
The barium oxalate obtained is then dried and calcined at 1300oC in argon atmosphere or vacuum for 2 hours and barium oxalate is converted to barium oxide which can be directly added to lithium oxalate solution. The barium oxide reacts with water to form barium hydroxide which then reacts with lithium oxalate to form barium oxalate (insoluble) and lithium hydroxide solution.
Commercial barium hydroxide has sodium up to 0.1% and it contributes to first 2 batches of lithium carbonate. But since barium oxalate is washed in each batch and regenerated the sodium content in barium gradually decreased as after 2 to 3 batches a highly pure lithium hydroxide or carbonate is obtained that surpasses the battery grade specifications. More than 90% barium is recovered in the form barium oxide and hydroxide, while some barium can’t be reused due to formation of barium carbonate.
Lithium carbonate lab Analysis –

Table 13:
Chemical Specifications
Li2CO3 99.5% min.
Cl 0.005%
Na 0.01%
Ca 0.02%
Mg 0.02 %
SO4 0.005%
Fe2O3 0.001 %
H2O 0.1 % Max.
Insoluble in Acid 0.02% Max.
B 0.001%
K 0.001%
LOI 0.4% Max.
Note - water used in the above batch synthesis is Demineralized water.

The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of:
? high value products
? process to obtain high purity of lithium carbonate/hydroxide;
• efficient and optimized solvent extraction process;
• high profit margins due to high recovery, purity and regeneration of a raw materials;
• For the solvent composition and the pH the consumption of sodium hydroxide (around 60%) is more as compared to ammonium hydroxide.
• Ammonium sulphate is generated which is high value product compared to sodium sulphate (traditional process)
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation

, C , Claims:WE CLAIM:
1. A solvent composition for lithium extraction from batteries comprising:
i. organophosphorus compounds consisting of:
a. at least one selected from Di(2-ethylhexyl) phosphoric acid, and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester in a range of 15 to 50% (v/v); and
b. tributyl phosphate (TBP) in a range of 2 to10% (v/v);
ii. at least one fatty alcohol selected from 2-octanol and iso-decanol in a range of 2 to10% (v/v); and
iii. at least one diluent selected from kerosene, and high paraffin oil in a range of 55 to 80% (v/v).

2. The solvent composition as claimed in claim 1 wherein the organophosphorus compounds are selected from Di(2-ethylhexyl) phosphoric acid in an amount of 20% (v/v) and the tributyl phosphate (TBP) in an amount of 5% (v/v); the fatty alcohol selected from 2-octanol is in an amount of 5% (v/v); and the diluent selected from the kerosene in an amount of 70% (v/v).

3. The solvent composition as claimed in claim 1 wherein the organophosphorus compounds are selected from 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester is in an amount of 30% (v/v) and the tributyl phosphate (TBP) is in an amount of 7.5 % (v/v); the fatty acid selected from 2-octanol is in an amount of 7.5 (v/v); and the diluent selected from kerosene in an amount of 55 % (v/v).

4. A process for lithium extraction comprising the steps of:
a. miling black mass sourced from batteries to obtain black mass having particle size less than 60 micron;
b. mixing water with the particles of black mass in a ratio of 1:3.5 to obtain slurry:
c. leaching the slurry with at least one leaching agent in predetermined conditions to obtain a leach liquor;
d. adding water to the leach liquor to obtain a first solution;
e. treating the first solution at a pH optimized in the range of 3.6 to 4.0 using a base for a time period in the range of 2 to 4 hours to obtain iron precipitates and a filtrate;
f. water washing the filtrate to obtain a second solution, followed by treating the second solution with an acid to obtain a first feed having a pH in the range of 2.4 to 3.4, wherein the filtrate is free from iron; and
g. solvent extracting the first feed with the solvent composition, to sequentially obtain lithium as lithium hydroxide.
5. The process as claimed in claim 4 wherein the base in step (e) is selected from ammonia (25%) to achieve a pH in the range of 3.6 to 4.0 to precipitate the iron; and to minimize the elemental losses in the filtrate,
wherein at the higher pH selected in the range of 3.6 to 4.0, 10% , aluminum is co precipitated along with iron; and the co precipitation of lithium is avoided.

6. The process as claimed in claim 4 wherein the higher amount of aluminum precipitates results in the loss of lithium due to precipitation of lithium aluminate with Al: Li in range of 3:1 to 5:1.

7. The process as claimed in claim 4 wherein the predetermined conditions comprises a temperature in the range of 75 to 85 °C; a time period is in the range of 5 to 7 hours; and the leaching agent is selected from sulphuric acid (H2SO4), hydrogen peroxide (H2O2), and a mixture thereof.

8. The process as claimed in claim 4 wherein lithium hydroxide, is carbonated in the presence of CO2 to obtain precipitates, followed by drying at a temperature in the range of 180 to 220oC to obtain lithium carbonate (Li2CO3) having a purity of 99.5%.
9. The process as claimed in claim 4 wherein the iron precipitates in step (e) are dried at a temperature of 150 °C for 2 hours and calcined at a temperature of 800 oC for 2 hours to obtain red iron oxide, wherein the iron precipitation efficiency is up to 99%.

10. The process as claimed in claim 4 wherein the solvent extraction steps further comprises:
• Mixing a first feed with the solvent composition A at a pH of 2.8 to extract aluminum and obtain aluminum depleted aqueous phase termed as “Al raffinate”, wherein the aluminum loaded in organic is back extracted using 2M sulphuric acid to obtain aluminium sulphate;
• adding 25% ammonia to the Al raffinate for a pH in the range of 4.00 to 4.5 to obtain a second feed;
• mixing the second feed with the solvent composition A at a pH of 4.2 to extract manganese and obtain a manganese depleted aqueous phase termed as “Manganese raffinate/third feed”, wherein the manganese loaded in organic is back extracted with 2 to 5 M sulphuric acid to obtain Mn sulphate ;
• Mixing the third feed at pH of 4.8 with solvent composition B to extract cobalt and cobalt depleted phase is termed as “Cobalt raffinate”, wherein the cobalt raffinate is then adjusted pH to 5.8 with ammonia to obtain “fourth feed” and the cobalt loaded in organic is then back extracted with 2 to 5 M sulphuric acid to obtain cobalt sulphate ;
• Mixing the fourth feed at a pH of 5.8 with solvent composition B to extract nickel and nickel depleted aqueous phase termed as “nickel raffinate/ fifth feed”, wherein the nickel loaded in organic is then back extracted with 2 to 5 M sulphuric acid;
• Mixing the fifth feed at a pH of 5.8 with solvent composition A to extract lithium and obtain lithium depleted aqueous phase termed as “Raffinate”, wherein the lithium loaded in organic phase is then back extracted with 0.5 M to 1 M oxalic acid solution to obtain lithium oxalate solution; and
• obtaining highly pure barium oxalate solution treated with barium hydroxide, to obtain barium oxalate precipitate and lithium hydroxide,

wherein the solvent composition is pre-treated with 0.5 M ammonium hydroxide in a ratio of 5:1 for solvent extracting aluminium, manganese, cobalt, Nickel and the lithium in the organic phase.

Dated 11 March 2024

Richa Arya, IN/PA-4149
TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI