The present invention relates to a process for recovery and recycling of nickel 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 nickel sulphate from them for its reuse for various industrial processes.
BACKGROUND OF THE INVENTION
Lithium-ion batteries (LiBs) are widely used nowadays in wandering devices, in hybrid electric vehicles as they are having distinguishing features including high cell voltage, self-discharge rate, desired size and weight, etc. The increased demand of LiBs led to challenges in their disposal which results in accelerated depletion of materials including nickel, cobalt, manganese, etc. Therefore, there is need of a process for recycling these spent LiBs to obtain the depleting materials and which help in cleaning the environment.
Pyro-metallurgical processes are widely used in industry for recovery of valuable metals from spent batteries with high efficiency and high productivity. These processes are involved with several defects including generation of hazardous gases, dust emissions, huge energy consumption and material loss. Moreover, hydrometallurgical processes are commonly used for refining residual alloys to their pure forms (salts, hydroxides, metals). Also, the hydrometallurgical process provides an alternative for recycling of spent batteries into pure metals or metal salts with low energy requirement and produce salts as by-products.
US5447552 relates to a hydrometallurgical process for the recovery of metals for the recovery and separation of nickel and/or cobalt by liquid-liquid extraction from aqueous solutions derived from the acid leaching of ores.

WO1997030181A1 relates to a process for the extraction of nickel from an aqueous feed solution comprising nickel, which comprises contacting the feed solution with an extractant comprising an amidobis (thiophosphoryl) compound.
WO2002022897A1 relates to a method of separating cobalt and nickel from other elements contained in an aqueous leach solution by adding a precipitating agent to the aqueous leach solution to precipitate elements including cobalt and nickel; separating and leaching the precipitate with an acid to form a leach liquor; and subjecting the leach liquor to successive solvent extraction steps with an organophosphoric acid and an organophosphinic acid.
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 nickel sulphate and utilization of by¬products, needs high pressure and high temperature, solution purification is needed to separate nickel from copper, 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 nickel sulphate from LiBs. For extraction of nickel 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 nickel 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 nickel 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 nickel sulphate by hydro metallurgy process.
Still another object of the present invention is to provide a process for extraction of nickel sulphate from waste lithium ion batteries (LiBs) by optimising filtration techniques, potential hydrogen balances, a reactor, evaporation techniques, and crystallizers during the hydro metallurgical 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 have been discarded and not in use to extract nickel sulphate 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 nickel sulphate from waste lithium ion batteries (LiBs) comprising steps of a) crushing a pre-determined amount of waste lithium ion batteries into pieces and processing said pieces with a group of chemicals and demineralised water in a reactor unit to obtain a slurry, b) filtering the slurry obtained in the step a) to obtain a filtrate, c) feeding the filtrate obtained in the step b) to a reactor unit, wherein pH of the filtrate 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 produce a cake, e) feeding the cake obtained in the step d) to a reactor unit for further processing with potassium

permanganate to form a solution, f) filtering the solution obtained in the step e) to remove the cake and to obtain a filtrate, g) feeding the filtrate obtained in the step f) again into the reactor unit and adjusting pH of a solution to 5.5, h) feeding the pH adjusted filtrate 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 to 11-11.5, j) filtering the solution obtained in the step i) upon increasing pH and distributing a filtrate into two streams for further salt conversion and to obtain a cake, k) processing the cake obtained in the step j) in reactor for changing pH to 3.5 using a desired amount of sulphuric acid, 1) filtering the solution obtained in the step k) for further processing of a filtrate, m) elevating pH of the filtrate obtained in the step 1) to 5.5 using a desired amount of ammonia for further chemical processing, n) executing a layer separation in a separating funnel through a bis/2,4,4-trimethylpentyl/phosphinic acid to obtain a top and a bottom layer, o) reducing volume of the bottom layer obtained in the step n) in evaporator to obtain nickel sulphate; and p) reducing the volume further for formation of crystals of nickel sulphate which settle at the bottom of a surface, thereby recovering nickel sulphate from said waste lithium ion batteries.
The present invention provides a method for recovery of nickel sulphate and recycling of waste lithium ion batteries for its reuse in several industrial processes. For the extraction of nickel sulphate from LiBs, a reactor, filtration techniques, potential hydrogen balances, evaporation techniques, and crystallizers are optimized during the hydrometallurgical process to provide a method which is convenient, easy to process and having lucid steps to follow with proper safety.
BRIEF DESCRIPTION OF THE DRAWINGS

A complete understanding of a process for recovery of nickel 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 nickel sulphate salt from waste lithium ion batteries (LiBs).
Figure 2 depicts an extracted nickel 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 have been discarded and not in use to extract nickel sulphate salt from them for its reuse for various industrial processes.
In a preferred embodiment, the present invention provides a process for recovery of nickel 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 hydro metallurgical process to obtain nickel sulphate salt.
Referring to Figure 1, a flow chart of process for recovery of nickel sulphate salt from waste lithium ion batteries (LiBs) is depicted. The present invention provides a process for recovery of nickel sulphate salt from waste lithium ion batteries (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 a cake and to obtain a filtrate;
g) feeding the filtrate obtained in the step f) again into 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;
NiS04 + NaOH ► Ni(OH)2 \ + Na2S04
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) processing the cake obtained in the step j) in reactor for changing pH to 3.5 of a solution using sulphuric acid;
Ni(OH)2 + H2S04 ► NiS04 + H20
1) filtering the solution obtained in the step k) for further processing of a filtrate;
m) elevating pH of the filtrate obtained in the step 1) to 5.5 using ammonia for further chemical processing;
n) executing a layer separation in a separating funnel through a bis/2,4,4-trimethylpentyl/ phosphinic acid to obtain a top and a bottom layer;
o) reducing volume of the bottom layer obtained in the step n) in evaporator to obtain nickel sulphate; and
p) reducing the volume further for formation of crystals of nickel sulphate which settle at the bottom of a surface with the recovery of around 500 g - 600 g (6.25% to 7.5%) of nickel sulphate from 8 kg powder of lithium ion battery.
EXAMPLE 1 Experimentation Analysis
The present invention provides a method for recovery of nickel sulphate salt and recycling of waste lithium ion batteries for its reuse in several industrial processes and the process comprises steps of:
a) crushing 8 kg waste lithium ion batteries into pieces in which 0.207 % of nickel is present and processing said pieces with a group of chemicals and demineralised water in a reactor unit to obtain a slurry, in which sulphuric acid is taken 3.6 litres, hydrogen peroxide is 6 litres and demineralised water is taken 62.4 litres;

b) filtering the slurry obtained in the step a) to obtain a filtrate, in which for filtering a mesh is taken of size 2 micron;
c) feeding the filtrate obtained in the step b) to a reactor unit, wherein pH of the filtrate is adjusted to 3.5 by using sodium hydroxide with 10 M concentration, in which the reactor unit is a batch reactor with specific capacity depending upon material fed, preferably material is chromium-nickel-molybdenum austenitic stainless steel with a thickness optimum to L/R ratio, with temperature 90°C and pressure 1.5 bar;
d) filtering the pH adjusted solution obtained in the step c) to produce a cake;
e) feeding the cake obtained in the step d) to a reactor unit for further processing with potassium permanganate to form a solution;
f) filtering the solution obtained in the step e) to remove the cake and to obtain a filtrate;
g) feeding the filtrate obtained in the step f) again into the reactor unit and adjusting pH of a solution to 5.5;
h) feeding the pH adjusted filtrate 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 to 11-11.5;
j) filtering the solution obtained in the step i) upon increasing pH and distributing a filtrate into two streams for further salt conversion and to obtain a cake;
k) processing the cake obtained in the step j) in reactor for changing pH to 3.5 using sulphuric acid with 2% concentration;

1) filtering the solution obtained in the step k) for further processing of a filtrate;
m) elevating pH of the filtrate obtained in the step 1) to 5.5 using 5.2 to 6.4ml of ammonia for further chemical processing;
n) executing a layer separation in a separating funnel through a bis/2,4,4-trimethylpentyl/phosphinic acid to obtain a top and a bottom layer;
o) reducing volume of the bottom layer obtained in the step n) in evaporator to obtain nickel sulphate in which as the density of both materials are different the dead time for layer separation is about 8 to 10 minutes, all the process is completed at room temperature, and then bottom layer is fed to evaporator for further volume reduction of the separated layer which contain nickel which turn to be nickel sulphate crystal after super-saturation, and in 3 hours it is able to reduce 1/10 of the volume (1032 liters were reduced to 104 liters); and
p) reducing the volume further for formation of crystals of nickel sulphate (1-2 % of crystals/100 ml of nickel sulphate solution) which settle at the bottom of a surface, thereby recovering nickel sulphate from said waste lithium ion batteries.
Hence, the yield was found to be 1-2%, in which 80-160 grams of 98% pure nickel sulphate was obtained as depicted in Figure 2. Few parameters were considered during this recovery method which are, during leaching of battery powder in reactor unit the speed of agitator was kept around 40-50 RPM and heated via steam in jacket of reactor unit. All the mixing vessels used in this recovery process are SAE 316L grade stainless steel which possess better corrosive resistance. Further, a speed of 1000 RPM was maintained of the agitator for better mixing and changing pH of larger volumes. One or more pipelines are used which are made of chromium-nickel-molybdenum

austenitic stainless steel and one or more con contact parts are used which are made up of stainless steel.
Therefore, the present invention provides a method for recovery of nickel sulphate salt and recycling of waste lithium ion batteries for its reuse in several industrial processes. For the extraction of nickel sulphate salt from LiBs a reactor, filtration techniques, potential hydrogen balances, evaporation techniques, and crystallizers are optimised during a hydro metallurgical 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 nickel sulphate from waste lithium ion based batteries comprising steps of:
a) crushing a pre-determined amount of waste lithium ion batteries into pieces and processing said pieces with a group of chemicals and demineralised water in a reactor unit to obtain a slurry;
b) filtering the slurry obtained in the step a) to obtain a filtrate;
c) feeding the filtrate obtained in the step b) to a reactor unit, wherein pH of the filtrate 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 produce a cake;
e) feeding the cake obtained in the step d) to a reactor unit for further processing with potassium permanganate to form a solution;
f) filtering the solution obtained in the step e) to remove the cake and to obtain a filtrate;
g) feeding the filtrate obtained in the step f) again into the reactor unit and adjusting pH of a solution to 5.5;
h) feeding the pH adjusted filtrate 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 to 11-11.5;

j) filtering the solution obtained in the step i) upon increasing pH and distributing a filtrate into two streams for further salt conversion and to obtain a cake;
k) processing the cake obtained in the step j) in reactor for changing pH to 3.5 using a desired amount of sulphuric acid;
1) filtering the solution obtained in the step k) for further processing of a filtrate;
m) elevating pH of the filtrate obtained in the step 1) to 5.5 using a desired amount of ammonia for further chemical processing;
n) executing a layer separation in a separating funnel through a bis/2,4,4-trimethylpentyl/phosphinic acid to obtain a top and a bottom layer;
o) reducing volume of the bottom layer obtained in the step n) in evaporator to obtain nickel sulphate; and
p) reducing the volume further for formation of crystals of nickel sulphate which settle at the bottom of a surface, thereby recovering nickel sulphate from said waste lithium ion batteries.
2. The process for recovery and recycling of nickel sulphate from waste lithium ion based batteries as claimed in claim 1, wherein said group of chemicals includes to sulphuric acid, hydrogen peroxide.
3. The process for recovery and recycling of nickel sulphate from waste lithium ion based batteries as claimed in claim 1, wherein said pieces are processed with said group of chemicals and said demineralised water in said reactor unit in step (a) at temperature ranging from 80 to 90°C for three to four hours.

4. The process for recovery and recycling of nickel sulphate from waste lithium ion based batteries as claimed in claim 1, wherein said reactor unit is a batch reactior with thickness optimum to L/R ratio.
5. The process for recovery and recycling of nickel sulphate from waste lithium ion based batteries as claimed in claim 1, wherein said desired amount of sodium hydroxide ranges from 5 to 10 M.
6. The process for recovery and recycling of nickel sulphate from waste lithium ion based batteries as claimed in claim 1, wherein said desired amount of sulphuric acid ranges from 1% to 2% concentration.
7. The process for recovery and recycling of nickel sulphate from waste lithium ion based batteries as claimed in claim 1, wherein said desired amount of ammonia ranges from 5 to 6 ml.
8. The process for recovery and recycling of nickel sulphate from waste lithium ion based batteries as claimed in claim 1, wherein said recovery of nickel sulphate ranges from 500 g to 600 g (6.25% to 7.5%) of nickel sulphate from 8 kg powder of lithium ion battery.