The present invention relates to a process for recovery and recycling of lithium carbonate from waste lithium ion batteries. More particularly, it relates to recycling of lithium ion-based batteries that has been discarded and not in use to extract lithium carbonate from them for its reuse for various industrial processes.
BACKGROUND OF THE INVENTION
Lithium-ion rechargeable battery (LiBs) usage has been widespread enabling the wireless revolution of portable electronics (e.g., cell phones, laptops, digital cameras, power tools, etc., and are widely used nowadays in electric vehicles (EVs) and intermittent energy storage as they are having high energy density and low prices substituting other secondary batteries due to lightness and good performance. Therefore, the recycling of metals from LiBs have become increasingly important for the economy and environment.
The widely used method for recycling of LiBs includes leaching and combination of calcination and leaching. The leaching method involves crushing or shredding of battery, leaching with acid and separation by precipitation, or by extraction. The leaching methods involves complex leachate composition and multiple separation steps creating large amounts of secondary waste. The combination method involves shredding of battery, calcinating, leaching with acid, separating the leached materials. However, this method has the additional disadvantage of high energy consumption caused by the heat-treating process. Besides, recovery rate of the electrode materials is low since some components of the electrode materials are burned into carbon dioxide and other harmful substances.
CN101942563B relates to a method for manufacturing lithium carbonate with less impurities. The method comprises the steps of firstly, washing the solvent-

extracted organic phase containing nickel and lithium with nickelic sulfuric solution and concentrating lithium in the cleaning liquid, secondly, only extracting residual nickel from the lithium-concentrated cleaning liquid with organic solvent, and thirdly, regulating the pH value of the extracted lithium-containing liquid with ammonia water.
CN104241724B relates to a method for recovery from waste and old LiBs to prepare battery-level lithium carbonate involving the steps of preparing slags of fluorine containing lithium which is subjected for leaching wherein lithium gets dissolved in water which is filtered to obtain rough lithium solution to which is added magnesium and pH is regulated to obtain refine solution of lithium to which is added carbonate for precipitation to obtain rough lithium carbonate which after washing obtains battery-level lithium carbonate product after drying.
KR101682217B1 relates to a method to manufacture high purity lithium carbonate by recycling lithium from an anode material of a used LiBs. The method comprises the steps of mixing and calcining an anode material, wet-milling a calcinated result using hydrochloric acid or sulfuric acid to leach the wet-milling result and inserting sodium carbonate or sodium hydroxide into a leaching liquid which is further purified and washed to obtain lithium carbonate.
However, methods for recycling of LiBs heretofore known suffer from a number of disadvantages including that the existing methods have low values for recovery of the LiBs salts including lithium carbonate and utilization of by-products, direct acid leaching of ores or concentrates using sulfuric acid have been largely unsuccessful, needs high pressure and high temperature, the recycled LiBs are too heavy, the transportation and the disassembly are inconvenient, the next recycling is inconvenient, and the inside of the recycled LiBs generates moisture.

Accordingly, there is a need for an approach that resolves problems of state of art to provide a simple process for recovery and recycling of salts including lithium carbonate from LiBs. For extraction of lithium carbonate salt from LiBs a reactor, filtration techniques, potential hydrogen balances, evaporation techniques and crystallizers need to be optimised during the hydrometallurgical process to provide a method which is convenient, easy to process and with lucid steps to follow with proper safety.
OBJECT OF THE INVENTION
The main object of the present invention is to provide a process for recovery and recycling of lithium carbonate from waste lithium ion batteries (LiBs) for its reuse for various industrial processes.
Another object of the present invention is to provide a process for extraction of lithium carbonate from waste lithium ion batteries (LiBs) comprising the steps of shredding of waste batteries to crushed lithium ion battery pieces /leaf, and recovery of lithium carbonate by hydrometallurgy process.
Still another object of the present invention is to provide a process for extraction of lithium carbonate from waste lithium ion batteries (LiBs) by optimising filtration techniques, potential hydrogen balances, a reactor, evaporation techniques, and crystallizers during the hydrometallurgical process to provide a method which is convenient, easy to process and with lucid steps to follow with proper safety.
SUMMARY OF THE INVENTION
The present invention relates to recycling of lithium ion batteries (LiBs) that has been discarded and not in use to extract lithium carbonate from lithium ion batteries (LiBs) for its reuse for various industrial processes.

In a preferred embodiment, the present invention provides a process for recovery of lithium carbonate from waste lithium ion batteries (LiBs) comprising the steps of crushing the batteries to crushed lithium ion battery pieces /leaf which is further processed by a hydro metallurgical process to obtain lithium carbonate salt.
In another preferred embodiment, the present invention provides a process for recovery of lithium carbonate salt from waste LiBs comprising the steps of: a) crushing the waste lithium ion batteries in to pieces/leafs which is processed with chemicals including but not limited to sulphuric acid, hydrogen peroxide and demineralised water in reactor at 90°C for four hours in a reactor unit to provide a slurry of reaction mixture; b) filtering the slurry of reaction mixture obtained in the step a) to obtain a filtrate and subjecting said filtrate for further processing; c) feeding the filtrate obtained in the step b) to a reactor wherein pH of the solution is adjusted to 3.5 using sodium hydroxide w/v; d) filtering the pH adjusted solution obtained in the step c) to receive a cake; e) feeding the cake obtained in the step d) to reactor for further processing with potassium permanganate to form a solution; f) filtering the solution obtained in the step e) to remove manganese oxide in form of cake and to obtain a filtrate; g) feeding the filtrate obtained in the step f) again in to the reactor and adjusting pH of a solution to 5.5; h) feeding the solution obtained in the step g) further for filtration to obtain a filtrate; i) processing of the filtrate obtained in the step h) by increasing pH of a solution to 11-11.5; j) filtering the solution obtained in the step i) and distributing a filtrate in to two streams for further salt conversion and to obtain a cake; k) evaporating filtrate kept aside for salt conversion from the step j) in evaporator for volume reduction; 1) feeding the solution obtained in the step k) to evaporator for reducing the volume to 80-90% of initial volume; m) feeding solution of said volume of the step 1) to the reactor and adding sodium carbonate at 90°C; n) filtering the solution obtained in the step m) to receive salt which is further cleaned using hot water; and o) drying the salt obtained in the step n) in tray dryer for 2 firs to

obtain lithium carbonate with the recovery in range of 90 g-100 g (1.125%-1.25%) of lithium carbonate from 8 kg powder of lithium ion battery.
The present invention provides a method for recovery of lithium carbonate and recycling of waste lithium ion batteries for its reuse in several industrial processes. For the extraction of lithium carbonate from LiBs a reactor, filtration techniques, potential hydrogen balances, evaporation techniques, and crystallizers are optimised during the hydrometallurgical process to provide a method which is convenient, easy to process and with lucid steps to follow with proper safety.
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 DRAWINGS
A complete understanding of a process for recovery of lithium carbonate salt from waste lithium ion batteries of the present invention may be obtained by reference to the following drawings:
Figure 1 elucidates a flowchart of extraction of lithium carbonate salt from waste lithium ion batteries (LiBs).
Figure 2 depicts an extracted lithium carbonate salt obtained from waste lithium ion batteries (LiBs).
DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described more fully hereinafter. 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 relates to recycling of LiBs that has been discarded and not in use to extract lithium carbonate salt from them for its reuse for various industrial processes.
In a preferred embodiment, the present invention provides a process for recovery of lithium carbonate from waste lithium ion batteries (LiBs) comprising the steps of crushing the batteries to crushed lithium ion battery pieces /leaf which is further processed by a hydro metallurgical process to obtain lithium carbonate salt.
Referring to Figure 1, a flowchart of extraction of lithium carbonate salt from waste lithium ion batteries is illustrated. The present invention provides a process for recovery of lithium carbonate salt from waste LiBs comprising the steps of:
a) crushing the waste lithium ion batteries in to pieces which is processed with chemicals including but not limited to sulphuric acid, hydrogen peroxide and demineralised water in reactor at 90°C for four hours in a reactor unit to provide a slurry of reaction mixture;
b) filtering the slurry of reaction mixture obtained in the step a) to obtain a filtrate and subjecting said filtrate for further processing;
c) feeding the filtrate obtained in the step b) to a reactor wherein pH of the solution is adjusted to 3.5 using sodium hydroxide w/v;

d) filtering the pH adjusted solution obtained in the step c) to receive a cake;
e) feeding the cake obtained in the step d) to reactor for further processing with potassium permanganate to form a solution;

f) filtering the solution obtained in the step e) to remove manganese oxide in form of cake and to obtain a filtrate;
g) feeding the filtrate obtained in the step f) again in to the reactor and adjusting pH of a solution to 5.5;
h) feeding the solution obtained in the step g) further for filtration to obtain a filtrate;
i) processing of the filtrate obtained in the step h) by increasing pH of a solution to 11-11.5;
j) filtering the solution obtained in the step i) and distributing a filtrate in to two streams for further salt conversion and to obtain a cake;
k) evaporating filtrate kept aside for salt conversion from the step j) in evaporator for volume reduction;
1) feeding the solution obtained in the step k) to evaporator for reducing the volume to 80-90% of initial volume;
m) feeding solution of said volume of the step 1) to the reactor and adding sodium carbonate at 90°C;
n) filtering the solution obtained in the step m) to receive salt which is further cleaned using hot water; and
o) drying the salt obtained in the step n) in tray dryer for 2 hrs to obtain lithium carbonate with the recovery in range of 90 g-100 g (1.125%-1.25%) of lithium carbonate from 8 kg powder of lithium ion battery.
Li2S04 + Na2C03 —► LiC03 + Na2S04
EXAMPLE 1 Experimentation Analysis

The present invention provides a process for recovery of lithium carbonate salt from waste lithium ion batteries (LiBs) from 8 kg powder of lithium ion battery which comprise of 0.24% of lithium, comprising steps of:
a) crushing the waste lithium ion batteries into pieces which is processed with chemicals including but not limited to sulphuric acid ranging between 3 to 4 litres, hydrogen peroxide ranging between 5.5 to 6.5 litres and demineralised water ranging between 60 to 65 litres in reactor at 90°C for four hours in a reactor unit to provide a slurry of reaction mixture;
b) filtering the slurry of reaction mixture obtained in the step a) to obtain a filtrate and subjecting said filtrate for further processing;
c) feeding the filtrate obtained in the step b) to reactor wherein pH of the solution is adjusted ranging between 3 to 4 using sodium hydroxide w/v ranging between 10 to 20 ml/100 ml of filtered solution;
d) filtering the pH adjusted solution obtained in the step c) to receive a cake;
e) feeding the cake obtained in the step d) to reactor for further processing with potassium permanganate ranging between 250 to 300 gm to form a solution;
f) filtering the solution obtained in the step e) to remove a cake and to obtain a filtrate;
g) feeding the filtrate obtained in the step f) again in to the reactor and adjusting pH of a solution ranging between 5 to 6;
h) feeding the solution obtained in the step g) further for filtration to obtain a filtrate;

i) processing of the filtrate obtained in the step h) by increasing pH of a solution ranging between 11 to 11.5;
j) filtering the solution obtained in the step i) and distributing a filtrate in to two streams for further salt conversion and to obtain a cake;
k) evaporating filtrate kept aside for salt conversion from the step j) in evaporator for volume reduction;
1) feeding the solution obtained in the step k) to evaporator for reducing the volume to 80-90% of initial volume;
m) feeding solution of said volume of the step 1) to the reactor and adding sodium carbonate at 90°C;
n) filtering the solution obtained in the step m) to receive salt which is further cleaned using hot water; and
o) drying the salt obtained in the step n) in tray dryer for 2 hrs to obtain lithium carbonate with the recovery in range of 90 g- 100 g (1.125% -1.25%) of lithium carbonate from 8 kg powder of lithium ion battery.
Li2S04 + Na2C03 —► LiC03 + Na2S04
Hence, through the present invention 90 g to 100 g (1.125%-1.25%) of lithium carbonate is recovered from 8 kg powder of lithium ion battery. Referring to Figure 2, lithium carbonate of white colour as recovered from the waste lithium ion battery is depicted.
Therefore, the present invention provides a method for recovery of lithium carbonate salt and recycling of waste lithium ion batteries for its reuse in several industrial processes. For the extraction of lithium carbonate salt from lithium ion batteries a reactor, filtration techniques, potential hydrogen balances, evaporation techniques and crystallizers are optimised during a

hydrometallurgical process to provide a method which is convenient, easy to process and with lucid steps to follow with proper safety.
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
We claim:

1. A process for recovery and recycling of lithium carbonate from waste lithium ion batteries comprising steps of:
a) crushing the waste lithium ion batteries into pieces and processing said pieces with chemicals in a reactor unit at predefined temperature and time to provide a slurry of reaction mixture;
b) filtering said slurry of reaction mixture obtained in said step a) to procure a filtrate;
c) feeding said filtrate obtained in said step b) to reactor wherein said solution is adjusted to a desired pH through sodium hydroxide w/v;
d) filtering said pH adjusted solution obtained in said step c) to procure a cake;
e) feeding said cake obtained in said step d) to reactor for processing with potassium permanganate to form a solution;
f) filtering said solution obtained in said step e) to remove manganese oxide in form of cake and to procure a filtrate;
g) feeding said filtrate obtained in said step f) again in to a reactor and adjusting said solution to a desired pH;
h) feeding said solution obtained in said step g) for filtration to procure a filtrate;
i) processing said filtrate obtained in said step h) by increasing said solution to a desired pH;

j) filtering said solution obtained in said step i) and distributing said filtrate into two streams for salt conversion and to procure a cake;
k) evaporating filtrate kept aside for salt conversion from said step j) in evaporator for volume reduction;
1) feeding the solution obtained in said step k) to evaporator for reducing the volume from the initial volume;
m) feeding solution obtained in said step 1) to said reactor and adding sodium carbonate at desired temperature;
n) filtering said solution obtained in said step m) to receive salt which is cleaned using hot water; and
o) drying the salt obtained in said step n) in tray dryer for a desired time to obtain lithium carbonate;
wherein:
said recovery of lithium carbonate is around 90 g-100 g (1.125%-1.25%) of lithium carbonate from 8 kg powder of lithium ion battery having purity of 98%.
2. The process for recovery and recycling of lithium carbonate from waste lithium ion batteries as claimed in claim 1, wherein said chemicals including but not limited to sulphuric acid ranging between 3 to 4 litres, hydrogen peroxide ranging between 5.5 to 6.5 litres and demineralised water ranging between 60 to 65 litres at 90°C for four hours in a reactor unit.
3. The process for recovery and recycling of lithium carbonate from waste lithium ion batteries as claimed in claim 1, wherein said pH of said solution is adjusted ranging between 3 to 4 in said step c) through sodium hydroxide w/v ranging between 10 to 20 ml/100 ml of filtered solution.

4. The process for recovery and recycling of lithium carbonate from waste lithium ion batteries as claimed in claim 1, wherein said potassium permanganate is ranging between 250 to 300 gm.
5. The process for recovery and recycling of lithium carbonate from waste lithium ion batteries as claimed in claim 1, wherein said reactor is a batch reactor with temperature ranging between 85 to 95°C and pressure ranging between 1 to 2 bar.
6. The process for recovery and recycling of lithium carbonate from waste lithium ion batteries as claimed in claim 1, wherein said pH of said solution is adjusted ranging between 5 to 6 in the said step g).
7. The process for recovery and recycling of lithium carbonate from waste lithium ion batteries as claimed in claim 1, wherein said pH of said solution is adjusted to 11 to 11.5 in said step i).
8. The process for recovery and recycling of lithium carbonate from waste lithium ion batteries as claimed in claim 1, wherein said solution obtained in said step k) is feed to an evaporator for reducing the volume to 80-90% of initial volume.
9. The process for recovery and recycling of lithium carbonate from waste lithium ion batteries as claimed in claim 1, wherein said solution obtained in said step 1) is feed to said reactor and adding sodium carbonate at temperature ranging between 85 to 95°C.