Description:FORM 2

THE PATENTS ACT, 1970

(39 of 1970)

&

THE PATENT RULES, 2003

COMPLETE SPECIFICATION

[See Section 10 and Rule 13]

TITLE:

“A PROCESS FOR PRODUCTION OF TITANIUM DIOXIDE FROM ANODE MATERIAL OF SPENT LITHIUM TITANATE BATTERIES”

APPLICANT:

ATTERO RECYCLING PVT. LTD.
A company incorporated under the Indian Companies Act, 1956
having address at
173, Raipur Industrial Area, Bhagwanpur, Roorkee,
Haridwar Uttarakhand - 247661, India

PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be performed:
FIELD OF THE INVENTION
The present invention relates to the field of spent lithium-ion batteries. More particularly, the present invention relates to a process for production of titanium dioxide from an anode material of spent lithium titanate batteries.

BACKGROUND OF THE INVENTION
The number of lithium-ion batteries (LIBs) is steadily increasing in order to meet the ever-growing demand for sustainable energy and a high quality of life for humankind. However, the resulting battery waste certainly poses safety hazards if not handled properly. Current commercial lithium ion batteries mainly contain transition metal oxides or phosphates, aluminum, copper, graphite, organic electrolytes containing harmful lithium salts and other chemicals. Therefore, the reuse and recycling of spent lithium ion batteries has been paid more and more attention by many researchers. However, due to the high energy density and high safety, the recycling of waste lithium ion batteries has great difficulties.
Spent lithium ion batteries (LIBs) include many valuable metals, such as lithium (Li), cobalt (Co), nickel (Ni), manganese (Mn), iron (Fe), copper (Cu) and aluminum (Al). The composition of these metals is not only similar to natural minerals, but the content of them is even higher than that of natural minerals. Consequently, the precious resource of spent LIBs should not be treated as waste in consideration of strategic materials and sustainable development. In addition to alleviating the shortages of raw materials, the recovery and reuse of spent lithium ion batteries (LIBs), can also bring huge economic value.
CN111020194A discloses a method for synthesizing a titanium aluminum alloy from waste lithium titanate positive and negative electrode powder. The method comprises the steps of: reduction leaching of the waste lithium titanate positive and negative electrode powder; copper separation and purification of leaching filtrate and two-step iron and aluminum removal; deep impurity removal of iron and aluminum removing liquid and step-by-step extraction of rare and noble metal cobalt and nickel; separation and purification of iron and aluminum removing slag and extraction of aluminum hydroxide; evaporation and lithium extraction of raffinate and titanium extraction; mixed calcination of metatitanic acid and aluminum hydroxide and fused salt electrolysis of titanium aluminum oxide.
WO2017215282A1 discloses a method for recycling of lithium in anode material of a lithium battery by means of an electrochemical process. This citation provides a method for recycling lithium in an anode material of a lithium battery by means of an electrochemical process. According to the method, the anode material of the lithium battery serves as an anode, a metal or carbon electrode serves as a cathode and an aqueous solution serves as an electrolyte; when an electric potential is applied, lithium ions in the anode material of the lithium battery are transferred to the electrolyte aqueous solution to form lithium containing solution. This citation is focused on recycling of lithium from an anode material of a lithium battery.
Kishore K. Jena et. al. (Energy Fuels, 35, 18257-18284), reported about battery chemistry, degradation mechanism, pretreatment processes and pyrometallurgical and hydrometallurgical methods. In the leaching of cathode-active materials, LiCoO2, with inorganic acid produces Cl2, SO2, and NO2 gases, which have adverse impacts on the environment. These gases react with moisture in the air to produce H2SO4, HNO3 and HCl acid molecules that later form acid rain.
Over the past years, many other methods, such as pyrometallurgy and hydrometallurgy were also known. However, the recycling processes known, are prone to generate large amount of harmful emissions, such as fluorine compounds, toxic organic compounds and greenhouse gases. Therefore, additional costs are required for exhaust gas treatment.
Therefore, there is a need to develop of a technology that is simple, cost-effective and environment friendly to overcome the aforesaid drawbacks. The present invention is an endeavour in this direction.

OBJECT OF THE INVENTION
The main object of the present invention is to provide a process for the production of titanium dioxide from spent lithium titanate batteries.
Another object of the present invention is to provide a process for the production of titanium dioxide from anode material of spent lithium titanate batteries.
Yet another object of the present invention is to provide a commercially feasible method for producing pure titanium dioxide from waste/spent lithium titanate batteries.
Yet another object of the present invention is to provide a method that ensures greater recovery (> 98%) of titanium with (>99%) purity of titanium dioxide.
Still another object of the present invention is to provide a method that is clean, green, and environmentally friendly.

SUMMARY OF THE INVENTION
The present invention relates to a method for producing titanium dioxide from anode material of spent lithium ion battery. The method is simple, easy to operate and economically attractive. The recovery of titanium dioxide from spent lithium titanate barriers is a chemical free process.
In an embodiment, the present invention provides a process for production of titanium dioxide from anode material of spent lithium titanate batteries, characterized in that, the method comprising the steps of: (a) treating an anode material of spent lithium titanate batteries with a suitable solution to remove an anode powder from an aluminium foil; (b) mixing the anode powder obtained in step (a) with a suitable acid and pugging at a pre-defined temperature for a pre-defined time to obtain a pugged anode powder; (c) leaching the pugged anode powder obtained in step (b) by agitating with a suitable acid to maintain the pH in a pre-determined range, for 2- 4 hours with a pre-defined solid-liquid ratio to obtain a slurry; (d) filtering the slurry obtained in step (c) to obtain a leach liquor for lithium recovery and a residue-I; (e) washing the residue-I obtained in step (d) with water followed by filtration to get a washed liquor and a residue-II and using the washed liquor in the next batch of leaching; and roasting the residue-II obtained in step (e) at a pre-determined temperature range for a pre-defined time to obtain pure titanium dioxide.
The present invention relates to a process for production of titanium dioxide. The process provides greater recovery of titanium (>98%) with purity (>99%) of titanium dioxide.
The above objects and advantages of the present invention will become apparent from the hereinafter set forth brief description of the drawings, detailed description of the invention, and claims appended herewith.

BRIEF DESCRIPTION OF THE DRAWING
An understanding of the process for the production of titanium dioxide from an anode material of spent lithium ion batteries of the present invention may be obtained by reference to the following drawings:
Figure 1 is a schematic representation for the production of titanium dioxide form anode material of spent lithium titanate batteries according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough, and will fully convey the scope of the invention to those skilled in the art.
The present invention now will be described hereinafter with reference to the detailed description, in which some, but not all embodiments of the invention are indicated. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. The present invention is described fully herein with non-limiting embodiments and exemplary experimentation.
The present invention provides a method for producing titanium dioxide from anode material of spent lithium ion battery. The method is simple, easy to operate and economically attractive. The recovery of titanium dioxide from spent lithium titanate barriers is a chemical free process.
In a preferred embodiment, the present invention provides a process for production of titanium dioxide from anode material of spent lithium titanate batteries, characterized in that, the method comprising the steps of: (a) treating an anode material of spent lithium titanate batteries with a suitable solution to remove an anode powder from an aluminium foil; (b) mixing the anode powder obtained in step (a) with a suitable acid and pugging at a pre-defined temperature for a pre-defined time to obtain a pugged anode powder; (c) leaching the pugged anode powder obtained in step (b) by agitating with a suitable acid to maintain the pH in a pre-determined range, for 2- 4 hours with a pre-defined solid-liquid ratio to obtain a slurry; (d) filtering the slurry obtained in step (c) to obtain a leach liquor for lithium recovery and a residue-I; (e) washing the residue-I obtained in step (d) with water followed by filtration to get a washed liquor and a residue-II and using the washed liquor in the next batch of leaching; and roasting the residue-II obtained in step (e) at a pre-determined temperature range for a pre-defined time to obtain pure titanium dioxide.
Here, the anode material of step (a) is an anode foil and the suitable solution of step (a) is sodium hydroxide (NaOH) solution (0.5%-2% w/v). The suitable acid of step (b) is selected from nitric acid (HNO3 (0.5-0.9 w/w)) or sulphuric acid (H2SO4 (0.3 – 0.6 w/w)).
Further, the pre-determined temperature of step (b) is in a range of 100°C to 200°C and the pre-defined time of step (b) is in a range of 4-8 hours. The suitable acid of step (c) is selected from 5-10% nitric acid (HNO3) or 5-10% sulphuric acid (H2SO4).
Additionally, pre-determined temperature of step (f) is in a range of 700-1000oC and the pre-defined time of step (f) is in a range of 6-8 hours. The leach liquor obtained in step (d) is sent to a lithium recovery section.
The process for production of titanium dioxide from spent lithium titanate batteries provides recovery of titanium in a range of 98% with purity in a range of 99% of titanium dioxide (TiO2).
Figure 1 shows a process flow sheet for the production of titanium dioxide from anode material of spent lithium titanate batteries.
EXAMPLE 1
EXPERIMENTATION ANALYSIS
Method for producing titanium dioxide from anode material of waste lithium titanate batteries
Batch 1
In batch-1, 0.45 kg of anode foil was washed with 4.5 L of sodium hydroxide (NaOH) (0.5% w/v) for 5 min. 0.25 kg of Al-foil was collected and the slurry was filtered to get the anode mass (0.2 kg) and wash liquor. The anode mass (0.2 kg) was mixed with 0.14 kg of nitric acid and pugged at 200°C for 4 hours. After 4 hours, the pugged material was allowed to cool to room temperature. The pugged material was then agitated with 0.93 L water for 3 hours by maintaining a pH of 0.5 with 0.093 L of HNO3. The slurry was then filtered to get the leach liquor (0.92 L) and 0.18 kg residue-I. The residue-I was washed with 0.18 L of water and the wash liquor was kept separately to use in the next batch for leaching. The residue-II (0.163 kg) obtained after washing was roasted at 800°C for 8 hours to get the pure titanium dioxide (0.145 kg). The chemical analysis of anode mass, pugged material, leach liquor and residue-II were shown in Table 1.
Table 1: Chemical analysis
Material Description Unit Elements
Li Ti Al Na
Anode mass % 3.6 43.2 1.05 0.28
Pugged Material % 3 37 0.88 0.24
Leach liquor g/L 7.3 0.025 1.93 0.53
Washed Liquor g/L 0.5 0.001 0.1 0.1
Residue-II % 0.1 52.86 0.15 0.03

Batch 2
In batch-2, 2.25 kg anode foil was washed with 22.5 L of sodium hydroxide NaOH (0.5% w/v) for 5 min. 1.25 kg of Al-foil was collected and the slurry was filtered to get the anode mass (1 kg) and wash liquor. The anode mass (1.0 kg) was mixed with 0.7 kg of nitric acid and pugged at 150oC for 6 hours. After 6 hours, the pugged material was allowed to cool to room temperature. The pugged material was agitated with 5 L of water for 4 hours by maintaining a pH of 0.5 with 0.5 L of HNO3. The slurry was then filtered to get the leach liquor (6 L) and 0.9 kg residue-I. The residue-I was washed with 0.9 L water and the wash liquor was kept separately to use in the next batch for leaching. The residue-II (0.80 kg) obtained after washing was roasted at 900oC for 6 hours to get the pure titanium dioxide (0.718 kg). The chemical analysis of anode mass, pugged material, leach liquor, and residue-II were shown in Table 2.
Table 2: Chemical analysis
Material Description Unit Elements
Li Ti Al Na
Anode mass % 3.83 42.7 0.33 0.54
Pugged Material % 3.05 34.15 0.26 0.43
Leach liquor g/L 5.95 0.023 0.29 0.7
Washed Liquor g/L 0.23 0.015 0.056 0.124
Residue-II % 0.11 53.35 0.14 0.05

Batch 3
In batch-3, 1.125 kg of anode foil was washed with 11.25 L of NaOH (0.5% w/v) for 5 min. 0.625 kg of Al-foil was collected and the slurry was filtered to get anode mass (0.5 kg) and wash liquor. The anode mass (0.5 kg) was mixed with 0.193 kg of sulphuric acid and pugged at 200°C for 4 hours. After 4 hours, the pugged material was allowed to cool to room temperature. The pugged material was agitated with 2.7 L water for 4 hours by maintaining a pH of 0.5 with 0.27 L sulphuric acid. The slurry was then filtered to get the leach liquor (3.12 L) and residue-I (0.41 kg). The residue-I was washed with 0.41 L of water and the wash liquor was kept separately to use in the next batch for leaching. The residue-II (0.396 kg) obtained after washing was roasted at 800°C for 8 hours to get the pure titanium dioxide (0.364 kg). The analysis of anode mass, pugged material, leach liquor and residue-II were shown in Table 3.
Table 3: Chemical analysis
Material Description Unit Elements
Li Ti Al Na
Anode mass % 3.6 43.5 1.98 0.28
Pugged Material % 2.69 32.6 1.48 0.21
Leach liquor g/L 5.6 0.035 3.05 0.36
Washed Liquor g/L 0.23 0.015 0.056 0.124
Residue-II % 0.11 54.75 0.02 0.06

The purity and impurity profile of the pure titanium dioxide produced in the above batches were determined by IS: 8862-1978 and Microwave Plasma Atomic emission spectra (MP-AES), respectively are shown in Table 4.
Table 4: Purity of titanium dioxide
Titanium Dioxide Unit Elements Purity
Li Al Na
Batch 1 % 0.11 0.16 0.03 99.17
Batch 2 % 0.12 0.15 0.04 99.13
Batch 3 % 0.12 0.02 0.06 99.19

Therefore, the present invention provides a simple, easy to operate and cost effective method for production of titanium dioxide from anode material of spent lithium titanate batteries.
Many modifications and other embodiments of the invention set forth herein will readily occur to one skilled in the art to which the invention pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
, Claims:CLAIMS

We claim:
1. A process for production of titanium dioxide from anode material of spent lithium titanate batteries, characterized in that, the method comprising the steps of:
a) treating an anode material of spent lithium titanate batteries with a suitable solution to remove an anode powder from an aluminium foil;
b) mixing the anode powder obtained in step (a) with a suitable acid and pugging at a pre-defined temperature for a pre-defined time to obtain a pugged anode powder;
c) leaching the pugged anode powder obtained in step (b) by agitating with a suitable acid to maintain the pH in a pre-determined range for 2- 4 hours with a pre-defined solid-liquid ratio to obtain a slurry;
d) filtering the slurry obtained in step (c) to obtain a leach liquor for lithium recovery and a residue-I;
e) washing the residue-I obtained in step (d) with water followed by filtration to get a washed liquor and a residue-II and using the washed liquor in the next batch of leaching; and
f) roasting the residue-II obtained in step (e) at a pre-determined temperature range for a pre-defined time to get pure titanium dioxide.

2. The process as claimed in claim 1, wherein the anode material of step (a) is an anode foil and the suitable solution of step (a) is sodium hydroxide (NaOH) solution (0.5%-2% w/v).

3. The process as claimed in claim 1, wherein the suitable acid of step (b) is selected from HNO3 (0.5-0.9 w/w) or H2SO4 (0.3 – 0.6 w/w).
4. The process as claimed in claim 1, wherein the pre-determined temperature of step (b) is in a range of 100°C to 200°C and the pre-defined time of step (b) is in a range of 4-8 hours.

5. The process as claimed in claim 1, wherein the suitable acid of step (c) is selected from 5-10% HNO3 or 5-10% H2SO4.

6. The process as claimed in claim 1, wherein the pre-determined pH of step (c) is in a range of 0.2-0.8 and the pre-defined solid-liquid ratio of step (c) is 1:4 to 5.

7. The process as claimed in claim 1, wherein pre-determined temperature of step (f) is in a range of 700-1000 0C and the pre-defined time of step (f) is in a range of 6 -8 hours.

8. The process as claimed in claim 1, wherein the leach liquor obtained in step (d) is sent to a lithium recovery section.

9. The process as claimed in claim 1, wherein the process provides recovery of titanium in a range of 98-99% with purity in a range of 99 -99.3% of titanium dioxide (TiO2).