DESC:FIELD OF THE INVENTION
The present invention relates to a process for recovery and recycling of sodium sulphate 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 sodium sulphate 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, and 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 burnt into carbon dioxide and other harmful substances.
US10883157 relates to processes for extracting and recovering lithium values from lithium bearing materials including removal of potassium sulphate and/or sodium sulphate from a lithium-bearing solution.
US4378275 relates to a process for the recovery of metal values from a metal-containing sulphide material containing at least one non-ferrous metal selected from zinc, copper, silver, gold, lead, cobalt, and nickel, in addition to iron.
US4378275A relates to a process for the recovery of metal values from a metal-containing sulphide material containing at least one non-ferrous metal selected from zinc, copper, silver, gold, lead, cobalt, and nickel, in addition to iron. In one of the steps the aqueous raffinate from the solvent extraction step contains a mixture of magnesium, sodium, chloride, and sulphate ions and in which the spray roasting step produces, in addition to hydrogen chloride, a solid mixture comprising sodium chloride, sodium sulphate, magnesium sulphate, and magnesium oxide which is subsequently separated to give magnesium oxide and sodium chloride and sulphate containing purge stream.
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 salts including sodium sulphate and utilization of by-products, direct acid leaching of ores or concentrates using sulphuric 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 sodium sulphate from LiBs. For extraction of sodium sulphate 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 sodium sulphate 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 sodium sulphate from waste lithium ion batteries (LiBs) comprising the steps of shredding of waste batteries to crushed lithium ion battery pieces/leaf, and recovery of sodium sulphate by hydrometallurgy process.
Still another object of the present invention is to provide a process for extraction of sodium sulphate 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 sodium sulphate from LiBs for its reuse for various industrial processes.
In a preferred embodiment, the present invention provides a process for recovery of sodium sulphate from waste lithium ion batteries (LiBs) comprising steps of a) crushing a pre-defined amount of waste lithium ion batteries into pieces which are processed with a group of chemicals and demineralised water in reactor to obtain 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 a desired amount of 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 pre-determined amount of potassium permanganate to form a solution, f) filtering the solution obtained in the step e) to remove manganese oxide in the 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 from 11 to 11.5, j) filtering the solution obtained in the step i) and distributing a filtrate into 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, l) feeding the solution obtained in the step k) to evaporator for reducing the volume from 80 to 90 % of initial volume, m) feeding solution of said volume of the step l) to the reactor and adding a desired amount of sodium carbonate, 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 a tray dryer to recover sodium sulphate.
The present invention provides a method for recovery of sodium sulphate and recycling of waste lithium ion batteries for its reuse in several industrial processes. For the extraction of sodium sulphate 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.

BRIEF DESCRIPTION OF THE DRAWINGS
A complete understanding of a process for recovery of sodium sulphate 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 sodium sulphate salt from waste lithium ion batteries (LiBs).
Figure 2 depicts an extracted sodium sulphate 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 sodium sulphate salt from them for its reuse for various industrial processes.
In a preferred embodiment, the present invention provides a process for recovery of sodium sulphate salt from waste lithium ion batteries comprising the steps of crushing the batteries to crushed lithium ion battery pieces/leaf, which is further processed by hydrometallurgical process to obtain sodium sulphate salt.
Referring to Figure 1, a flow chart of a process for recovery of sodium sulphate salt from waste lithium ion batteries (LiBs) is depicted. The present invention provides a process for recovery of sodium sulphate salt from waste LiBs comprising the steps of:
a) crushing the waste lithium ion batteries into 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 the 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 into 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;
l) 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 l) 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 sodium sulphate with the recovery in range of 12 kg-13 kg (150% to 162.5%) of sodium sulphate from 8 kg powder of lithium ion battery.
Li2SO4 + Na2CO3 LiCO3 + Na2SO4

EXAMPLE 1
Experimentation Analysis
The present invention provides a process for recovery of sodium sulphate salt from waste lithium ion batteries comprising the steps of:
a) crushing the waste lithium ion batteries into 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; wherein the sulphuric acid was taken 3.6 litres, hydrogen peroxide was taken 6 litres and demineralised water was taken 62.4 litres;
b) filtering the slurry of reaction mixture obtained in the step a) to obtain a filtrate, and subjecting said filtrate for further processing; wherein the filtration is done through a mesh unit with mesh size of 2 microns;
c) feeding the filtrate obtained in the step b) to a reactor wherein pH of the solution is adjusted to 3.5 using 10 to 20ml 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 250 to 300 gm of potassium permanganate to form a solution;
f) filtering the solution obtained in the step e) to remove manganese oxide in the 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 into 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;
l) 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 l) 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 sodium sulphate with the recovery in range of 12 kg-13 kg (150% to 162.5%) of sodium sulphate from 8 kg powder of lithium ion battery.
The reactor used in this method is a batch reactor with temperature 90°C, pressure 1.5 bar. Further around 12 kg-13 kg (150% to 160.25%) of sodium sulphate is recovered from 8 kg powder of lithium ion battery as depicted in Figure 2.
Therefore, the present invention provides a method for recovery of sodium sulphate salt and recycling of waste lithium ion batteries for its reuse in several industrial processes. For the extraction of sodium sulphate salt from LiBs 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:CLAIMS

We claim:

1. A process for recovery of sodium sulphate salt from waste lithium ion batteries comprising steps of:
a) crushing a pre-defined amount of waste lithium ion batteries into pieces which are processed with a group of chemicals and demineralised water in reactor to obtain 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 a desired amount of 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 pre-determined amount of potassium permanganate to form a solution;
f) filtering the solution obtained in the step e) to remove manganese oxide in the 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 from 11 to 11.5;
j) filtering the solution obtained in the step i) and distributing a filtrate into 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;
l) feeding the solution obtained in the step k) to evaporator for reducing the volume from 80 to 90% of initial volume;
m) feeding solution of said volume of the step l) to the reactor and adding a desired amount of sodium carbonate;
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 a tray dryer to recover sodium sulphate.
2. The process for recovery of sodium sulphate salt from waste lithium ion batteries as claimed in claim 1, wherein said pre-defined amount of waste lithium ion batteries ranges from 7 to 8 kg.
3. The process for recovery of sodium sulphate salt from waste lithium ion batteries as claimed in claim 1, wherein said group of chemicals includes sulphuric acid, hydrogen peroxide.
4. The process for recovery of sodium sulphate salt from waste lithium ion batteries as claimed in claim 1, wherein said pieces which are processed with said group of chemicals and demineralised water in said reactor at temperature ranging from 80°C to 90°C for four to five hours.
5. The process for recovery of sodium sulphate salt from waste lithium ion batteries as claimed in claim 1, wherein said reactor is a batch reactor.
6. The process for recovery of sodium sulphate salt from waste lithium ion batteries as claimed in claim 1, wherein said desired amount of sodium carbonate ranges from 10 to 20 ml that is added in said reactor at temperature ranging from 80°C to 90°C.
7. The process for recovery of sodium sulphate salt from waste lithium ion batteries as claimed in claim 1, wherein said salt obtained in the step n) is dried in said tray dryer for 2 to 3 hrs.
8. The process for recovery of sodium sulphate salt from waste lithium ion batteries as claimed in claim 1, wherein said recovery is in range of 12 kg -13 kg (150% to 162.5%) of sodium sulphate.