Acid free process and apparatus for recycling waste primary lithium batteries (PLB)

Abstract

The present invention relates to an improved process and apparatus for recycling waste PLB without employing any acids. The process of the present invention avoids using acid input for extracting lithium from PLB. The process of the present invention includes the steps of discharging the waste PLB in a discharge tank, shredding the discharged PLB in a shredder, separating coarser casing particles and fine insoluble impurities and purifying the impure solution using purifying chemical to obtain recycled lithium. The process of present invention recovers up to 95% lithium present in the PLB as Lithium carbonate with an acid free process.

Description

ACID FREE PROCESS AND APPARATUS FOR RECYCLING WASTE PRIMARY LITHIUM BATTERIES (PLB)FIELD OF THE INVENTION

[0001] The present disclosure relates to a technical field of recycling and pre-treatment of waste primary lithium batteries (PLB). Particularly, the present disclosure relates to an improved process and apparatus for recycling waste PLB without employing any acids.BACKGROUND OF THE INVENTION

[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[0003] The growing global dependence on portable electronics, electric vehicles (EVs), and renewable energy storage solutions has led to a significant rise in the production and use of lithium-based batteries. Primary lithium batteries, which are non-rechargeable, are commonly used in devices such as cameras, hearing aids, remote controls, and some medical devices. Although these batteries are efficient and provide a high energy density, their disposal and recycling present a major environmental challenge. The improper disposal of primary lithium batteries poses serious environmental and safety risks, including the release of toxic materials, risk of fire or explosion, and the accumulation of non-biodegradable waste in landfills. As such, recycling these batteries is crucial not only for environmental sustainability but also for conserving valuable resources and preventing ecological harm.

[0004] Primary lithium batteries are single-use, non-rechargeable batteries that derive their energy from lithium metal or lithium compounds. Unlike rechargeable lithium-ion (Li- ion) batteries, which can be reused multiple times, primary lithium batteries are designed to be discarded after their energy is depleted. These batteries are commonly used in low-drain, long-life applications, such as in watches, cameras, and security devices. They are also used in critical applications such as medical implants and defense systems where long-lasting, reliable power is essential.

[0005] The advantages of primary lithium batteries include their ability to deliver a higher energy density compared to other types of batteries, which makes them suitable for devices that require consistent and long-lasting power. However, this efficiency comes at a cost. Once depleted, primary lithium batteries are difficult to dispose of in anenvironmentally responsible manner, as they contain hazardous materials and have a higher potential for environmental damage than other battery types.

[0006] Although there are recent innovations done to replace the anode lithium metal to other less reactive metals as described in W02020259480, the Lithium Primary battery currently dominate the market for niche application requiring a stable power supply over a long period of time up to 20 years. Further, the PLB contains significant quantity of Lithium (3.5-5% w / w of battery) which making it one of the most concentrated sources of Lithium available when compared to secondary Li-Ion Battery chemistries which contain up to 1.2 % and 2.0 % w / w of Lithium respectively.

[0007] The environmental impacts of improper disposal of primary lithium batteries are manifold. Lithium, as a metal, is highly reactive and can cause fires or explosions if it is exposed to heat, moisture, or physical damage. When disposed of in landfills, lithium batteries can leak harmful chemicals such as lithium salts, acidic gases such as SO2, HC1, heavy metals (such as cobalt and nickel), and toxic substances, potentially contaminating soil and water sources. Additionally, these batteries take hundreds to thousands of years to decompose, further exacerbating the environmental burden.

[0008] Even if they do not directly cause fires or leaks, primary lithium batteries contribute to the growing e-waste crisis. As electronic products become obsolete or end-of- life, they generate a large amount of waste, and without proper recycling, valuable materials are lost. The limited availability of lithium (a finite resource) makes the need for efficient recycling and resource recovery all the more pressing.

[0009] Given the serious environmental and health hazards associated with improper disposal, recycling primary lithium batteries is an important part of reducing their ecological footprint. Recycling not only helps prevent the release of harmful chemicals but also conserves valuable resources, reduces the demand for new mining operations, and lowers the carbon footprint associated with the extraction and transportation of raw materials.

[0010] The Chinese patent application, CN102244309A discloses a process for recovering valuable metals from waste lithium batteries, comprising the processing steps of pretreatment, a leaching process, chemical subtraction, extraction separation and the like, thus realizing comprehensive recovery of valuable metals such as cobalt, copper, nickel, aluminium and the like.

[0011] The US patent application, US20190152797A1 discloses method for preparing nickel / manganese / lithium / cobalt sulfate and tricobalt tetraoxide from battery wastes comprising the steps of dissolving battery wastes with acid, removing iron and aluminum,removing calcium, magnesium and copper, carrying extraction separation, and carrying out evaporative crystallization to prepare nickel sulfate, manganese sulfate, lithium sulfate, cobalt sulfate or / and tricobalt tetraoxide. By using the method, multiple metal elements, such as nickel, manganese, lithium and cobalt, can be simultaneously recovered from the battery wastes, the recovered products are high in purity and can reach battery grade, battery-grade tricobalt tetraoxide can also be directly produced.

[0012] The Chinese patent application, CN102162034A discloses a process for recovering valuable metals from waste lithium batteries, comprising the processing steps of pretreatment, a leaching process, chemical subtraction, extraction separation and the like, thus realizing comprehensive recovery of valuable metals such as cobalt, copper, nickel, aluminum and the like.

[0013] The present state does not have adequate technology to recycle the PLB and make significantly lower share in lithium battery recycling. This means PLB often get mixed with other lithium battery chemistries which is very dangerous as the explosion from PLB may set off chain reaction for secondary batteries. The present recycling processes have various drawbacks such as using acids which lead to corrosion of equipment, high temperature pyrolysis process for pretreatment of PLB using concentrated sulfuric acid which increases carbon footprint of process due to high energy consumption and toxic gases release during process, and loss of yield of lithium.

[0014] Therefore, there is an unmet need in the art to provide an improved process and apparatus for recycling waste PLB that is acid free, simple and energy efficient as well as provides high yield and purity.OBJECTIVE OF THE INVENTION

[0015] An objective of the present invention is to provide an improved process and apparatus for recycling waste primary lithium batteries (PLB).

[0016] Another objective of the present invention is to provide an improved process and apparatus for recycling waste primary lithium batteries (PLB) that is simple, acid free and industrially viable.

[0017] Another objective of the present invention is to provide an improved process and apparatus for recycling waste primary lithium batteries (PLB) that achieves high purity and high yield.

[0018] Another objective of the present invention is to provide an improved process and apparatus for recycling waste primary lithium batteries (PLB) that can handle all types of PLBs.SUMMARY OF THE INVENTION

[0019] The present invention generally relates to an improved process and apparatus for recycling waste PLB without employing any acids. The process of the present invention avoids using acid input for extracting lithium from PLB. The process / system of the present invention can recover up to 95% lithium present in the PLB as Lithium carbonate of purity above 99.7% with an acid free process and utilizes minimal chemicals and energy and generates less chemical residue. The process of the present invention offers significant advantages over tradition lithium mining process in terms of carbon footprint, water and energy consumption.

[0020] In an aspect, the present invention relates to an acid free process / system for recycling waste Primary Lithium Batteries (PLB), wherein the process comprises the steps of:(a) discharging the waste PLB in a discharge tank 102 mixture of conducting solution & water 104 to obtain discharged PLB;(b) shredding the discharged PLB in a shredder 110 by a continuous circulation of the solution from a solution storage tank 106 at a temperature in a range of 60°C to 80°C to obtain shredded slurry;(c) separating coarser casing particles including finer insoluble impurities from the shredded slurry in a solid liquid separation unit 112 to obtain impure solution;(d) purifying the impure solution in subsystem 201 by adding purifying chemicals to obtain purified solution; and(e) adding carbonating chemicals in subsystem 301 to the purified solution to obtain recycled lithium.

[0021] In another aspect of the present invention, the purifying chemicals is selected from the group consisting of KOH, NaOH, NH4OH, K2CO3, (NH-ifiCO?. Na2COv Ca(OH)2, Mg(0H)2and combination thereof.

[0022] In another aspect of the present invention, the carbonating chemicals is selected from the group consisting of K2CO3, (NH4)2CO3, Na2CO3, and CO2.

[0023] In another aspect, the present invention relates to an apparatus for recycling waste Primary Lithium Batteries (PLB), wherein the apparatus comprises:(a) discharge tank 102 configured to receive water from water unit 104 to maintain adequate level to completely immerse the waste PLB and to receive a solution from a solution storage tank 106 to reach a discharging solution of required conductivity;(b) a scrubber 108 configured with the discharge tank 102 to neutralize any acidic gases released during the discharging;(c) a shredder 110 configured to receive discharged contents of PLB along with the partial solution from the discharge tank 102 to initiate wet shredding process and to receive the solution in circulation from a solution storage tank 106 during the shredding process;(d) a solid liquid separation unit 112 configured to receive shredded slurry from the shredder 110 and to separate the coarser casing particles including finer insoluble impurities and impure solution;(e) sub system 201 configured to receive the impure solution of predetermined concentration and purify it in multiple steps by addition of multiple chemicals in a sequence at a predetermined molar ratio to the impurities; and(f) sub system 301 configured to receive purified solution containing metal impurities in detectable quantity and produces lithium carbonate solid through a final single purification step.

[0024] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments.BRIEF DESCRIPTION OF FIGURES

[0025] The accompanying drawings are included to provide a clear understanding of the present invention and a detailed description, and they constitute a part of this complete specification.

[0026] Figure 1 depicts flow diagram of the acid free process for recycling waste Primary Lithium Batteries (PLB) of the present invention.

[0027] Figure 2 depicts the flow diagram or design of the apparatus of recycling waste primary lithium batteries of the present invention.DETAILED DESCRIPTION OF THE INVENTION

[0028] The following is a complete description of the disclosure's embodiments. The embodiments are described in such a way that the disclosure is clearly communicated. The level of detail provided, on the other hand, is not meant to limit the expected variations of embodiments; rather, it is designed to include all modifications, equivalents, and alternatives that come within the spirit and scope of the current disclosure as defined by the attached claims. Unless the context indicates otherwise, the term "comprise" and variants such as "comprises" and "comprising" throughout the specification are to be read in an open, inclusive meaning, that is, as "including, but not limited to."

[0029] When "one embodiment" or "an embodiment" is used in this specification, it signifies that a particular feature, structure, or characteristic described in conjunction with the embodiment is present in at least one embodiment. As a result, the expressions "in one embodiment" and "in an embodiment" that appear throughout this specification do not necessarily refer to the same embodiment. Furthermore, in one or more embodiments, the specific features, structures, or qualities may be combined in any way that is appropriate.

[0030] Unless the content clearly demands otherwise, the singular terms "a," "an," and "the" include plural referents in this specification and the appended claims. Unless the content explicitly mandates differently, the term "or" is normally used in its broad definition, which includes "and / or."

[0031] All processes described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0032] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.

[0033] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

[0034] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and / or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description that follows, and the embodiments described herein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.

[0035] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

[0036] It should also be appreciated that the present invention can be implemented in numerous ways, including as a system, a method or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as processes. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention.

[0037] The present invention generally relates to an improved process and apparatus for recycling waste PLB without employing any acids. The process of the present invention avoids using acid input for extracting lithium from PLB. The process of the present invention can recover up to 95% lithium present in the PLB as Lithium carbonate with an acid free process and utilizes minimal chemicals and energy and generates less chemical residue.

[0038] In an embodiment, figure 2 demonstrates the flow diagram or design of the apparatus of recycling waste primary lithium batteries. The system for processing PLB comprises of three sub system units: Subsystem 101 designed to safely discharge, shred and extract lithium from the PLB and filter out any insoluble impurities present in the lithium solution. Subsystem 201 designed to remove any soluble impurities present in the lithium solution. Subsystem 301 designed to produce lithium salt and remove any insoluble impurity present in the lithium salt.

[0039] In another embodiment of the present invention, the sub system 101 comprises of discharging tank 102 configured to discharge the PLB by dipping them in a conducting solution to completely discharge them. The conducting solution is obtained by mixing a partof solution obtained from the solution storage tank 106. The discharged PLB is shredded where there is a continuous circulation of the solution from solution storage tank 106 to maintain the temperature and safely shred the battery. The shredded particles are passed through a solid liquid separation unit 112 to segregate and isolate the coarser particles including casing, finer particles present inside the battery including carbon / nickel and / or sulfur. This controlled extraction ensured the lithium is concentrated before passing onto next stage. The solution obtained is passed into the solution storage tank which operates within the limits set for lithium concentration. The discharging tank 102 and shredder 110 in subsystem 101 is connected to a scrubber 108 to neutralize any acidic gases released during the process.

[0040] In another embodiment of the present invention, the subsystem 201 comprises of multiple reactors to remove soluble metal salt impurities present in the impure solution by adjusting the pH of solution using a base and addition of fluoride source. This includes multiple stages for removing multiple impurities. Removing alkali earth and transition metals impurities M (Al, Fe, Mn, Ni, Cu, Mn, Mg, Ti, etc) as given in the chemical reactions.M+2+ OH’ = M(0H)2M+3+ OH’ = M(0H)3

[0041] In another embodiment of the present invention, the removing of alkaline earth metal AE (Calcium, Magnesium, etc) is as follows.AE+2+ 2F’ = AEF2

[0042] In another embodiment of the present invention, the subsystem 301 comprises producing lithium carbonate from the concentrated lithium solution by addition of carbonate source followed by purification.2Li++ CO32’ = Li2CO3Li2CO3+ H2O + CO2= 2 LiHCO3(aq) + Impurities J, 2LiHCO3+ Heat = Li2CO3+ H2O + CO2

[0043] In an embodiment, the present invention relates to an acid free process for recycling waste Primary Lithium Batteries (PLB), wherein the process comprises the steps of:(a) discharging the waste PLB in a discharge tank 102 comprising a mixture of conducting solution & water from water unit 104 to obtain discharged PLB;(b) shredding the discharged PLB in a shredder 110 by a continuous circulation of the solution from a solution storage tank 106 at a temperature in a range of 60°C to 80°C to obtain shredded slurry;(c) separating coarser casing particles including finer insoluble impurities from the shredded slurry in a solid liquid separation unit 112 to obtain impure solution;(d) purifying the impure solution in subsystem 201 by adding purifying chemicals to obtain purified solution; and(e) adding carbonating chemicals in a subsystem 301 to the purified solution to obtain recycled lithium.

[0044] In another embodiment of the present invention, the purifying chemicals is selected from the group consisting of KOH, NaOH, NH4OH, K2CO3, (NtLfiCCh. Na2COs, Ca(OH)2, Mg(0H)2 and combination thereof.

[0045] In another embodiment of the present invention, the purifying chemicals is selected from the group consisting of KOH, NaOH, NH40H, Ca(OH)2, and Mg(OH)2.

[0046] In another embodiment of the present invention, the carbonating chemicals is selected from the group consisting of K2CO3, (NH4)2CO3, Na2CO3, and CO2.

[0047] In another embodiment of the present invention, the carbonating chemicals is selected from K2CO3, and Na2CO3.

[0048] In another embodiment, the present invention relates to an acid free process for recycling waste Primary Lithium Batteries (PLB), wherein the process comprises the steps of:(a) discharging the waste PLB in a discharge tank 102 comprising a conducting solution to obtain discharged PLB;(b) shredding the discharged PLB in a shredder 110 by a continuous circulation of the solution from a solution storage tank 106 at a temperature in a range of 60°C to 80°C to obtain shredded slurry;(c) separating coarser casing particles and fine insoluble impurities from the shredded slurry in a solid liquid separation unit 112 to obtain impure solution;(d) purifying the impure solution in a subsystem 201 by adding purifying chemicals selected from the group consisting of KOH, NaOH, NH4OH, K2CO3, (NH4)2CO3, Na2CO3, Ca(OH)2, Mg(0H)2 and combination thereof to obtain purified solution; and(e) adding carbonating chemicals in a subsystem 301 selected from K2CO3, (NH4)2CO3, Na2CO3, and CO2 to the purified solution to obtain recycled lithium.

[0049] In another embodiment of the present invention, the conducting solution is selected from the group consisting of LiCl, Li2SC>3, NaCl, Na2SC>4, KC1, K2SO3, CaCfi. and MgCL: and conductivity of the conducting solution is in a range of 50 mS / cm to 1000 mS / cm. Preferably, in the range of 150 mS / cm to 500 mS / cm.

[0050] In another embodiment of the present invention, the concentration of the conducting solution is 1 molar to 5 molar.

[0051] In another embodiment of the present invention, the purifying chemical is present in a concentration of 0.5 molar to 2 molar.

[0052] In another embodiment of the present invention, the purifying step is three stage or two stage steps, wherein the purifying chemicals are added at different stages to separate different impurity.

[0053] In another embodiment of the present invention, the carbonating chemical is present in a concentration of 0.5 molar to 2 molar.

[0054] In another embodiment of the present invention, the recycled lithium is lithium carbonate having purity over 99.7%.

[0055] In another embodiment of the present invention, the process achieves the yield of greater than 95%.

[0056] In another embodiment, the present invention relates to an apparatus for recycling waste Primary Lithium Batteries (PLB), wherein the apparatus comprises:(a) discharge tank 102 configured to receive water from water unit (104) to maintain adequate level to completely immerse the waste PLB and to receive a solution from a solution storage tank 106 to reach a discharging solution of required conductivity;(b) a scrubber 108 configured with the discharge tank 102 to neutralize any acidic gases released during the discharging;(c) a shredder 110 configured to receive discharged contents of PLB along with the partial solution from the discharge tank 102 to initiate wet shredding process and to receive the solution in circulation from a solution storage tank 106 during the shredding process;(d) a solid liquid separation unit 112 configured to receive shredded slurry from the shredder 110 and to separate the coarser casing particles along with fine insoluble impurities and impure solution;(e) sub system 201 configured to receive the impure solution of predetermined concentration and purify it in multiple steps by addition of multiple chemicals in a sequence at a predetermined molar ratio to the impurities; and(f) sub system 301 configured to receive purified solution containing metal impurities in detectable quantity and produces lithium carbonate solid through a final single purification step.

[0057] In another embodiment of the present invention, the solution storage tank 106 serves as extraction temporary storage as well as provide heat transfer medium to the shredder 110 and the solution in circulation act as temperature control to prevent overheating and explosion of PLB.

[0058] In another embodiment of the present invention, the solution storage tank 106 is configured to transfer the solution of the predetermined concentration.

[0059] In another embodiment of the present invention, the sub system 201 configured to send the purified solution to sub system 301 after removing impurities.

[0060] According to the present invention, the process is fast and safe discharge of PLB followed by temperature-controlled shredding. The process of present invention is also closed loop process to increase the yield of lithium recovery of above 95%.

[0061] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions, or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.EXAMPLES

[0062] The present invention is further explained in the form of the following examples. However, it is to be understood that the following examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Figure 1 depicts the flow diagram of the acid free process for recycling waste Primary Lithium Batteries (PLB).Example 1:

[0063] PLB (1 Kg) was discharged in a solution with conductivity of 100-150 mS / cm over a period of 7-10 days. Shredding of the PLB was carried out using controlled temperature by circulating and sprinkling the solution to maintain the temperature during shredding below 70°C. The concentration of the solution obtained was 1.5 M- 2.5 M. The solution obtained was transferred to sub system 201 wherein calcium hydroxide in slurry form is added to remove the impurities in three stages. In the first stage, 1 to 1.25 mol equivalent of impurities was added to the solution to remove iron / aluminium / copper impurities. In the stage two, added 0.5 to 0.8 mol equivalent of impurities to the solution to remove nickel, manganese, magnesium impurities. In stage three, calcium / magnesium impurities were removed by adding 2 to 3.5 mol equivalent of sodium fluoride. After removalof all impurities, the purified solution containing only lithium & sodium in detectable quantities was obtained. The purified solution was transferred to subsystem 301 and carbonated using addition of 1.3 to 1.5 molar ratio of potassium carbonate to obtain pure lithium carbonate (247 g).Example 2:

[0064] PLB (1 Kg) was discharged in a solution with conductivity of 900-1100 mS / cm over a period of 5-7 days. Shredding of the PLB was carried out using controlled temperature by circulating and sprinkling the solution to maintain the temperature during shredding below 90°C. The concentration of solution obtained is 5-6 M. The solution obtained was transferred to sub system 201 wherein calcium hydroxide in slurry form is added to remove the impurities in two stages. In the first stage, 1 to 1.5 mol equivalent of impurities was added to the solution to remove iron / aluminium / copper / calcium / zinc impurities. In the second stage, 0.5 to 1.5 mol equivalent of impurities was added to the solution to remove Nickel, Manganese, Magnesium Impurities. After removing all impurities, the purified solution containing only lithium in detectable quantities was obtained. The purified solution was transferred to subsystem 301 and carbonated using 1.5 to 2.5 molar ratio of sodium carbonate to obtain pure lithium carbonate (252 g).Example 3:

[0065] PLB (1 Kg) was discharged in a solution with conductivity of 500-700 mS / cm over a period of 7-10 days. Shredding the PLB was carried using controlled temperature by circulating and sprinkling the solution to maintain the temperature during shredding below 90°C. The concentration of solution obtained is 1.5- 3 M. The process as example 2 is followed but the solution is transferred to sub system 201 wherein 6-12 M potassium hydroxide in solution form is added to remove the impurities in two stages. In the first stage, 1 to 2.5 mol equivalent of impurities was added to the solution to remove iron / aluminium / copper impurities. In the second stage, 0.5 to 1.5 mol equivalent of impurities was added to the solution to remove Nickel, Manganese, Magnesium Impurities. After removing all impurities, the purified solution containing only lithium & potassium in detectable quantities was obtained. The purified solution was transferred to subsystem 301 and carbonated using 1.3 to 1.8 molar ratio of potassium carbonate to obtain pure lithium carbonate (260 g).Example 4:

[0066] PLB (1 Kg) was discharged in a solution with conductivity of 300-500 mS / cm over a period of 5-7 days. Shredding the PLB was carried using controlled temperature by circulating and sprinkling the solution to maintain the temperature during shredding below 70°C. The concentration of solution obtained is 2.5 to 5 M. The process as example 2 is followed but the solution is transferred to sub system 201 wherein magnesium hydroxide in slurry form is added to remove the impurities in three stages. In the first stage, 1 to 2 mol equivalent of impurities was added to the solution to remove iron / aluminium / copper impurities. In the second stage, 0.5 to 1.5 mol equivalent of impurities was added to the solution to remove Nickel, Manganese, Magnesium Impurities. In third stage, the magnesium impurities were removed by adding 2 to 3.5 mol equivalent of sodium fluoride. After removing all impurities, the purified solution containing only lithium & sodium in detectable quantities was obtained. The purified solution was transferred to subsystem 301 and carbonated using 1.4 to 2.5 molar ratio of sodium carbonate to obtain pure lithium carbonate (258 g).

[0067] The following table summarizes the examples of the present invention.

[0068] The foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention.ADVANTAGES OF THE PRESENT INVENTION

[0069] The present invention provides a process of recycling waste PLB that provides high purity recycled lithium carbonate.

[0070] The present invention provides a process of recycling waste PLB that is free of acid and suitable for the industrial scale processing of PLB.

[0071] The present invention provides a process of recycling waste PLB that can handle all possible type of PLB including Li / SOCl2, Li / MnO2, Li / SO2, Li / I2.

[0072] The present invention provides a process of recycling waste PLB that increases the yield of lithium recovery above 95% and provides Li2CC>3 in highly pure form with purity of above 99.7%.

Claims

We Claim:

1. An acid free process for recycling waste Primary Lithium Batteries (PLB), wherein the process comprises the steps of:(a) discharging the waste PLB in a discharge tank (102) comprising mixture of water and a conducting solution to obtain discharged PLB, wherein conductivity of the conducting solution is in a range of 50 mS / cm to 1000 mS / cm, wherein concentration of the conducting solution is 1 molar to 5 molar;(b) shredding the discharged PLB in a shredder (110) by a continuous circulation of the solution from a solution storage tank (106) at a temperature in a range of 60°C to 90°C to obtain shredded slurry;(c) separating coarser casing particles and fine insoluble impurities from the shredded slurry in a solid liquid separation unit (112) to obtain impure solution;(d) purifying the impure solution in subsystem (201) by adding purifying chemicals selected from the group consisting of KOH, NaOH, NH40H, K2CO3, (NH4)2CO3, Na2CC>3, Ca(OH)2, Mg(OH)2or combination thereof to obtain purified solution, wherein the purifying chemicals is present in a concentration of 0.5 molar to 2 molar; and(e) adding carbonating chemicals in subsystem (301) selected from K2CO3, (NH4)2CO3, Na2CO2, and CO2to the purified solution to obtain recycled lithium, wherein the carbonating chemicals is present in a concentration of 0.5 molar to 2 molar.

2. The process as claimed in claim 1, wherein the conducting solution is LiCl, Li2SC>3, NaCl, Na2SO3, KC1, K2SO3.

3. The process as claimed in claim 1, wherein the recycled lithium is lithium carbonate having purity over 99.7%.

4. An apparatus for recycling waste Primary Lithium Batteries (PLB), wherein the apparatus comprises:(a) discharge tank (102) configured to receive water from water unit (104) to maintain adequate level to completely immerse the waste PLB and to receive a solution from a solution storage tank (106) to reach a discharging solution of requiredconductivity, wherein conductivity of the conducting solution is in a range of 50 mS / cm to 1000 mS / cm, wherein concentration of the conducting solution is 1 molar to 5 molar;(b) a scrubber (108) configured with the discharge tank (102) to neutralize any acidic gases released during the discharging;(c) a shredder (110) configured to receive discharged contents of PLB along with the partial solution from the discharge tank (102) to initiate wet shredding process and to receive the solution in circulation from a solution storage tank (106) during the shredding process;(d) a solid liquid separation unit (112) configured to receive shredded slurry from the shredder (110) and to separate the coarser casing particles along with fine insoluble impurities and impure solution;(e) sub system (201) configured to receive the impure solution of predetermined concentration and purify it in multiple steps by addition of multiple purifying chemicals in a sequence at a predetermined molar ratio to the impurities, wherein the purifying chemicals is present in a concentration of 0.5 molar to 2 molar; and(f) sub system (301) configured to receive purified solution containing metal impurities in detectable quantity and produces lithium carbonate solid through a final single purification step by adding carbonating chemicals, wherein the carbonating chemicals is present in a concentration of 0.5 molar to 2 molar.

5. The apparatus as claimed in claim 4, wherein the solution storage tank (106) serves as extraction temporary storage as well as provide heat transfer medium to the shredder (108) and the solution in circulation act as temperature control to prevent overheating and explosion of PLB.

6. The apparatus as claimed in claim 4, wherein the solution storage tank (106) is configured to transfer the solution of the predetermined concentration.

7. The apparatus as claimed in claim 4, wherein the sub system (201) is configured to send the purified solution to sub system 301 after removing impurities.

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