FIELD OF THE INVENTION
The present invention relates to a method and apparatus for roasting spent lithium batteries. More particularly, it relates to a method and apparatus for roasting spent lithium batteries with low emission of harmful fumes and that requires minimum use of external heat energy.

BACKGROUND OF THE INVENTION
Roasting plays an important role in recycling and/or waste management of e-waste. The roasting is carried to remove or to dismantle embedded components of the electronic devices. Roasting is required for thermal decomposition of resin parts including organic matrix and other insulating materials present in the battery packs. During the recovery process, the roasting step must be conducted with an optimum temperature range, so that the metal parts present in the lithium batteries remain unaffected and can be recovered in its purest form.
The main limitation observed during a roasting process is the emissions of harmful fumes that pollute the environment. Also, the temperature regulation during the roasting process has been a matter of concern and requires special attention of operators to avoid degradation of metallic and other recyclable parts present in the battery. Ideally, the temperature of the lithium ion batteries should be maintained below the melting point of the metal parts so that they remain unaffected of the temperatures.
Further, the known roasting approaches require external energy sources that increases the cost of processing and also creates an inconvenience in the maintenance of internal temperatures within permissible limits. Hence, this problem should be focused and it must be overcome.
US8696785 discloses a method for recycling a battery pack includes steps of: roasting the battery pack that houses a battery assembly that is in a charged condition, as it is, dismantling the roasted battery pack and separating the battery pack into unit cells and parts other than the unit cells, comminuting the unit cells obtained by separation, washing and screening the comminuted cells, dehydrating a slurry below a sieve after screening and recovering metals used for positive and negative electrodes, and recovering metal containing nickel by magnetically separating metal remaining on the sieve after screening, using a magnet. The main drawback of this invention is heating of battery packs at various units that require external energy sources increasing the cost.
In order to overcome limitations of the state of the art, there is a need of some new and effective approaches that should not rely upon the requirement of external heat energy sources, can easily maintain the roasting temperature and should provide safe and effective roasting process in terms of low emission of fumes.

OBJECT OF THE INVENTION
The main object of the present invention is to provide a method and apparatus for roasting spent lithium ion batteries for recycling for e-waste management.
Yet another object of the present invention is to provide an apparatus that utilizes minimum amount of heat energy for roasting spent lithium ion batteries.
Yet another object of the present invention is to provide an effective method of roasting the pre-processed spent lithium ion batteries with minimal use of heat energy.
Yet another object of the present invention is to provide an approach that utilizes heat energy from the battery components for roasting lithium ion batteries and hence, reduces the necessity of external heat energy.
Yet another object of the present invention is to provide an apparatus designed to reduce fume emission during battery roasting.
Yet another object of the present invention is to provide an approach to provide a low temperature, energy saving, safe roasting approach for spent lithium ion batteries.

SUMMARY OF THE INVENTION
Accordingly, the present invention relates to a method and apparatus for roasting the pre-processed spent lithium batteries. The proposed apparatus involves a roasting mechanism that utilizes minimum amount of heat energy for roasting the lithium batteries. To achieve low heat energy based roasting process, the batteries are first punched to create holes or apertures on the outer surface. Thereafter, the punched batteries are kept inside the apparatus to initiate the roasting process.
In the roasting method, the holes created on the battery surface assists in heat penetration that causes organic matrix to burn. Initially, the batteries are exposed to an initial temperature in the range of 250-300 ºC that allows the organic matrix to catch fire. The energy released from the organic matrix is utilized to maintain temperature in the roasting apparatus. The temperature of the apparatus is kept within a range in between 400-600 ºC that helps to reduce the necessity external heat energy required for a roasting process.
The roasting apparatus of the invention comprises: a cabinet, atleast one heating area provided at least one wall of the cabinet, a cabinet cover; at least one nozzle provided for fumes neutralization emitted from batteries, atleast one means to regulate temperature within the apparatus, and at least one slidably movable frame configured to hold a roasting tray to get it inserted inside the apparatus for direct exposure to the heating area.
In another embodiment of the proposed invention, a method of roasting lithium ion batteries is provided. The method comprises the steps of:
a. punching the spent lithium ion batteries to create small holes in the battery using a suitable punching approach, prior to fed into the roasting apparatus;
b. keeping the batteries into a direct exposure of heating area in the roasting apparatus;
c. providing the initial temperature in the range of 250-300 ºC that allows the organic matrix to catch fire and burn;
d. maintaining the optimum temperature within the apparatus for a complete roasting of the batteries;
wherein,
the batteries utilize the internal heat energy generated upon initial burning of organic matrix and/or other components; said generated heat raises the temperature within the apparatus, which is regulated/maintained within a desired range, suitable for roasting.

BRIEF DESCRIPTION OF DRAWING
The various features, advantages and other uses of the present e-waste recycling method and apparatus will become more apparent by referring to the following detailed description and drawings in which:
FIG. 1 is a schematic view of the apparatus according to an embodiment of the present invention; and
FIG. 2 is the perspective view of the apparatus according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
The present invention now will be described hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. 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.
In the most preferred embodiment of the present invention an apparatus (200) for roasting spent lithium batteries is provided as depicted in Fig. 2, wherein said apparatus (200) comprising:
at least one cabinet (202) having a conical top (1) and an opening at one side towards the bottom end (2);
at least one roasting area (204) to roast the lithium batteries;
at least one nozzle (206) fitted at the conical top (1);
at least one means for neutralizing fumes said means installed in the nozzle (206);
at least one means of heating (208) to provide an initial temperature for roasting the lithium batteries;
at least one means for temperature regulation for controlling an optimum temperature in the roasting area (204);
at least one slidable and detachable roasting tray (210) to feed spent lithium batteries;
at least one slidably movable frame (212) fitted in the opening in said cabinet (200) to hold said roasting tray (210);
wherein,
said means for neutralizing fumes is a scrubber to remove unwanted pollutants from the fumes in the nozzle (204);
said means for temperature regulation is a suction valve with adjustable suction rate to maintain the optimum temperature.

In another preferred embodiment of the present invention, a method of roasting lithium ion batteries comprising the steps of:
a. punching the lithium ion batteries to create small holes in the batteries;
b. feeding the punched batteries into a roasting tray (210) of a roasting apparatus (200);
c. keeping the batteries in a direct exposure of roasting area (204) in the roasting apparatus (200);
d. providing an initial temperature that allows the organic matrix to catch fire and burn;
e. maintaining an optimum temperature within the apparatus using a temperature regulation means for complete roasting of the batteries;
wherein,
the batteries utilize the internal heat energy generated upon burning of organic matrix and/or other components;
said generated heat energy raises the temperature further within the apparatus, which is maintained at a desired optimum temperature, suitable for roasting.
the initial temperature is in the range of 250-300 ºC and the the optimum temperature is in range of 400-600 ºC.

FIG. 1 is a schematic view of the apparatus (200) according to an embodiment of the present invention. In this embodiment, the apparatus (200) comprises at least one nozzle (206) installed with a scrubber to treat the fumes evolved during the roasting process. The scrubber introduces acid gas sorbents to treat the fumes. Further, the apparatus (200) comprises at least one heating means (208) to provide initial heat to the punched batteries kept inside the roasting tray (not provided in the figure). The punched or pre-processed batteries are fed into the apparatus (200) using a roasting tray (210) which is kept on a slidably movable frame (212) provided to feed in and draw out the batteries inside the roasting apparatus (200).

Referring to FIG. 2, another perspective view of the apparatus (200) is provided. In this embodiment, a detachable roasting tray (210) is placed in the frame. The roasting tray provides a roasting area (204) for roasting the pre-processed lithium ion batteries. The batteries are placed in the roasting tray (210) and fed in the apparatus (200) in such a manner that the roasting area (204) comes into a direct exposure of the heating means (208). The roasting area (204) receives heat energy from the heating means (208) and creates a thermal environment in the roasting area (204). The organic matrix of the batteries catches fire and starts burning which leads to generate heat energy in the roasting apparatus (200). The heat generated in the apparatus (200) rises the temperature in the apparatus (200) up to about 500 ºC which is regulated through a temperature regulation means, preferably a suction valve. Closing the suction valve increases temperature in apparatus (200) and opening the suction valve allows the fresh air into the apparatus (200) and leaving the fumes along with hot air to towards the scrubber through nozzle. Thus the suction rate with the help of valve was adjusted in such a way to maintain the temperature of the chamber and allow the fumes to be scrubbed.
In another embodiment of the present invention, the internal temperature of the apparatus is maintained in between 400-600 ºC for at least two hours for a complete roasting of lithium ion batteries. After completion, the roasting tray is slidably moved out and taken for further recycling.
EXAMPLE 1
A BATCH TESTING OF METHOD FOR ROASTING SPENT LITHIUM BATTERIES UTILIZING THE NOVEL ROASTING APPARATUS
Batch 1: In a 100 Kg batch of spent lithium ion batteries, the roasting process was tested. Initially the batteries were punched using an instrument to create holes on the surface. Thereafter, the punched batteries were kept inside a roaster to initiate the roasting process. In order to optimize the roasting process, the process was studied at three different temperatures (400, 500 and 600 oC) for 2 h. In the first batch of roasting at 400 oC, the roasted batteries were cooled down to room temperature and weighed. Weight of the material was found to be 88 kg. Then it was shredded using a shredder having twin shaft with water spraying and shearing type cutting facility. The shredded material was passed through a sieve through having a mesh (600 µm) followed by filtration, 49.8 kg of cake (dry wt.), 23.1 kg of aluminum and 14.5 kg of copper foil were collected.

Batch 2: In another 100 Kg batch of the same spent lithium ion batteries, the roasting process was tested at 500 oC for 2 h. The spent batteries were first punched and then roasted using a roaster. After roasting, the roasted batteries were cooled down to room temperature and weighed. Weight of the material was found to be 87 kg. Then it was shredded using a shredder having twin shaft with water spraying and shearing type cutting facility. The shredded material was passed through a sieve through having a mesh (600 µm) followed by filtration, 45.8 Kg of cake (dry wt.), 26.9 Kg of aluminum and 14.1 Kg of copper foil were collected.

Batch 3: Roasting process of another 100 Kg batch of the same spent lithium ion batteries was tested at 600 oC for 2 h. In the similar manner, the spent batteries were first punched and then roasted using a roaster. After roasting, the roasted batteries were cool down to room temperature and weighed. Weight of the material was found to be 86 kg. Then it was shredded using a shredder having twin shaft with water spraying and shearing type cutting facility. The shredded material was passed through a sieve through having a mesh (600 µm) followed by filtration, 47.8 Kg of cake (dry weight), 24.7 Kg of aluminum and 10.8 Kg of copper foil were collected.

The detail chemical analysis of the powder obtained in the above three batches is presented in the Table 1. From the Table 1, it is observed that the roasting temperature 500 oC is suitable for the process as the powder contain high concentration of cobalt with minimum impurities.

Table 1 Chemical composition of dried powder

From the Table 1, it is observed that the roasting temperature 500 oC is suitable for the process as the powder contain high concentration of cobalt with minimum impurities.

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.

We Claim:

1. An apparatus (200) for roasting spent lithium batteries comprising:

at least one cabinet (202) having a conical top (1) and an opening at one side towards the bottom end (2);
at least one roasting area (204) to roast the lithium batteries;
at least one nozzle (206) fitted at the conical top (1);
at least one means for neutralizing fumes said means installed in the nozzle (206);
at least one means of heating (208) to provide an initial temperature for roasting the lithium batteries;
at least one means for temperature regulation for controlling an optimum temperature in the roasting area (204);
at least one slidable and detachable roasting tray (210) to feed spent lithium batteries;
at least one slidably movable frame (212) fitted in the opening in said cabinet (200) to hold said roasting tray (210);
wherein,
said means for neutralizing fumes is a scrubber to remove unwanted pollutants from the fumes in the nozzle (204); and

said means for temperature regulation is a suction valve with adjustable suction rate to maintain the optimum temperature.

2. The apparatus as claimed in claim 1 wherein, said suction valve when closed increases the temperature in the apparatus and when opened allows fresh air in the apparatus and directs the fumes towards the nozzle for treatment.

3. The apparatus as claimed in claim 1 wherein, said scrubber introduces acid gas sorbents to treat the fumes.

4. The apparatus as claimed in claim 1 wherein, the initial temperature provided is in the range of 250-300 ºC.

5. The apparatus as claimed in claim 1 wherein, the optimum temperature provided is in the range of 400-600 ºC.

6. A method of roasting lithium ion batteries comprising the steps of:

a. punching the lithium ion batteries to create small holes in the batteries;
b. feeding the punched batteries into a roasting tray (210) of a roasting apparatus (200);
c. keeping the batteries in a direct exposure of roasting area (204) in the roasting apparatus (200);
d. providing an initial temperature that allows the organic matrix to catch fire and burn;
e. maintaining an optimum temperature within the apparatus using a temperature regulation means for complete roasting of the batteries;
wherein,
the batteries utilize the internal heat energy generated upon burning of organic matrix and/or other components; and
said generated heat energy raises the temperature further within the apparatus, which is maintained at a desired optimum temperature, suitable for roasting.

7. The method as claimed in claim 6 wherein, the initial temperature is in the range of 250-300 ºC.

8. The method as claimed in claim 6 wherein, the optimum temperature is in range of 400-600 ºC.