Process for purifying and producing high purity particulate graphite material for use in lithium ion batteries - Patents.com

Abstract

Described herein is a process for purifying and producing a high-purity coated particulate graphite material suitable for use in lithium-ion batteries (LiBs). More specifically, the process includes agglomerating a graphite feed or treating the graphite feed with a flocculating agent to produce an agglomerated particulate graphite feed, and reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture containing the purified agglomerated particulate graphite material and the chlorine-containing gas enriched in chlorinated impurities. The process can further include an alkaline leaching step. Coated particulate graphite material containing a purity greater than 99.95 wt.% C and its use as an anode material in rechargeable LiBs are also disclosed.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 260,370, filed August 18, 2021. The contents of the referenced applications are incorporated herein by reference. [Background technology]

[0002] 1.Technical Field This disclosure relates to the field of physical and chemical refining. More specifically, this disclosure relates generally, but not exclusively, to the physical and chemical refining of graphite. Even more specifically, this disclosure relates generally, but not exclusively, to processes for refining and producing high purity particulate graphite material suitable for use in batteries. Even more specifically, this disclosure relates generally, but not exclusively, to processes for refining and producing coated high purity graphite particles suitable for use in batteries. This disclosure also relates to high purity particulate graphite particles and coated high purity particulate graphite particles and their use as anode materials in rechargeable lithium ion batteries (LiBs).

[0003] 2.Background All LiBs use particulate graphite as the anode electrode material. The particle size range of this graphite is typically 5-30 micrometers. A key requirement for the graphite is that it must have a low impurity content, with typical industry standards for total impurities of ≤500 ppm, on a weight basis.

[0004] There are two common graphite sources for LiBs: synthetic graphite and mined natural flake graphite (NFG). Typical mined NFG products are concentrates with purity ranging from 92-98% carbon by weight and therefore must be purified before they can be used in LiBs. Summary of the Invention [Problem to be solved by the invention]

[0005] Currently, there are two methods practiced on a commercial scale to purify NFG for use in LIBs. The first method uses a combination of hydrofluoric acid (HF) and other acids to remove impurities by solubilizing them, as described, for example, in CN101367517B, which is incorporated herein by reference. The method can purify NFG to specifications of greater than 99.95 wt.% C. However, this method has significant drawbacks. First, HF is an extremely hazardous substance in liquid or vapor form, and its use entails managing significant health, safety, and environmental issues. Second, HF is an expensive reagent, and given the quantities typically required, this purification method incurs high processing costs. And third, the method generates large amounts of fluoride-contaminated liquid and solid waste that must be disposed of in an environmentally acceptable manner.

[0006] The second method practiced on a commercial scale to purify NFG for use in LiBs uses extremely high temperatures (e.g., above 2,500° C.) to remove impurities as volatiles in the gas phase. This method has significant technical challenges. First, there is the challenge of achieving temperatures above 2,500° C. in a system that allows large-scale processing of graphite while preventing oxidation. Second, related to the first problem, there is the short reactor lifetime and subsequent high operating costs. Third, there is the challenge of processing very fine graphite particles in a controllable and efficient manner. The implication of these challenges is that the furnaces used for this method are very costly and limited in their specific processing capacity.

[0007] Therefore, improved processes for purifying and producing high purity particulate graphite materials from synthetic graphite or NFG, suitable for use in LiBs, and overcoming the technical and economic constraints of existing commercial processes, are of commercial interest. [Means for solving the problem]

[0008] The present disclosure generally relates to processes for purifying and producing high purity particulate graphite material suitable for use in batteries. The present disclosure also generally relates to processes for purifying and producing coated high purity graphite particles suitable for use in batteries. In one aspect of the present disclosure, the coating comprises a carbon coating. The present disclosure also relates to high purity particulate graphite particles and their use as an anode material in rechargeable lithium ion batteries (LiBs). The present disclosure also relates to coated high purity particulate graphite particles and their use as an anode material in rechargeable lithium ion batteries (LiBs). In one aspect of the present disclosure, the coating comprises a carbon coating. In a further aspect of the present disclosure, the high purity particulate graphite particles exhibit a purity of greater than 99.95 wt.% C.

[0009] In one aspect, the present disclosure relates to a process for purifying graphite comprising reacting a particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising purified particulate graphite material and a chlorine-containing gas enriched in chlorinated impurities, and separating the purified particulate graphite material from the mixture.

[0010] In one aspect, the present disclosure relates to a process for purifying graphite comprising treating a particulate graphite feed with a flocculating agent to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising purified agglomerated particulate graphite material and a chlorine-containing gas rich in chlorinated impurities, and separating the purified agglomerated particulate graphite material from the mixture.

[0011] In one aspect, the present disclosure relates to a process for purifying graphite comprising leaching a particulate graphite feed using an alkaline leach solution to produce a leached graphite feed material, treating the leached graphite feed with a flocculating agent to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising the purified agglomerated particulate graphite material and a chlorinated impurity-rich chlorine-containing gas, and separating the purified agglomerated particulate graphite material from the mixture.

[0012] In one aspect, the present disclosure relates to a process for purifying graphite comprising agglomerating a particulate graphite feed using mechanical means to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising purified agglomerated particulate graphite material and the chlorine-containing gas enriched in chlorinated impurities, and separating the purified agglomerated particulate graphite material from the mixture.

[0013] In one aspect, the present disclosure relates to a process for purifying graphite comprising leaching a particulate graphite feed using an alkaline leach solution to produce a leached graphite feed material, agglomerating the leached graphite feed using mechanical means to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising purified agglomerated particulate graphite material and a chlorinated impurity-rich chlorine-containing gas, and separating the purified agglomerated particulate graphite material from the mixture.

[0014] In one aspect, the disclosure relates to a process for purifying graphite comprising agglomerating a particulate graphite feed using mechanical briquetting, with or without an agglomerating agent, to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising purified agglomerated particulate graphite material and a chlorinated impurity-rich chlorine-containing gas, and separating the purified agglomerated particulate graphite material from the mixture.

[0015] In one aspect, the disclosure relates to a process for purifying graphite comprising leaching a particulate graphite feed using an alkaline leach solution to produce a leached graphite feed material; agglomerating the particulate graphite feed using mechanical briquetting with or without a flocculating agent to produce an agglomerated particulate graphite feed; reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising the purified agglomerated particulate graphite material and the chlorinated impurity-rich chlorine-containing gas; and separating the purified agglomerated particulate graphite material from the mixture.

[0016] In one embodiment, the present disclosure relates to a particulate graphite material comprising a purity greater than 99.95 wt.% C.

[0017] In one aspect, the present disclosure relates to an anode material for lithium-ion batteries (LiBs) comprising a particulate graphite material of purity greater than 99.95 wt.% C.

[0018] In one aspect, the present disclosure relates to graphite particles for lithium ion batteries (LiBs), the graphite particles having a purity greater than 99.95 wt.% C.

[0019] In one aspect, the present disclosure relates to graphite particles for lithium ion batteries (LiBs), the graphite particles having a purity greater than 99.95 wt.% C, and a sintered binder material connecting to at least a portion of a surface of the graphite particles.

[0020] In one aspect, the present disclosure relates to graphite particles for lithium ion batteries (LiBs), the graphite particles having a purity greater than 99.95 wt. % C, the graphite particles including a carbon coating.

[0021] Also disclosed in the context of this disclosure are embodiments 1-155. Embodiment 1 is a process for purifying graphite, the process comprising reacting a particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising purified particulate graphite material and a chlorine-containing gas laden with chlorinated impurities, and separating the purified particulate graphite material from the mixture. Embodiment 2 is the process of embodiment 1, further comprising leaching the particulate graphite feed using an alkaline leach solution to produce a slurry, and subjecting the slurry to a separation step, where the leaching is preformed prior to reacting with the chlorine-containing gas. Embodiment 3 is the process of embodiment 1 or 2, further comprising treating the particulate graphite feed with a flocculating agent. Embodiment 4 is the process of any one of embodiments 1-3, where the chlorinated impurities laden with chlorine-containing gas is quenched to remove impurities. Embodiment 5 is the process of embodiment 4, where the chlorinated impurities comprise metal chlorides. Embodiment 6 is the process of embodiment 2, wherein the leaching is carried out using an aqueous NaOH solution or an aqueous KOH solution. Embodiment 7 is the process of embodiment 6, wherein the aqueous NaOH solution comprises about 10% to about 50% NaOH by weight. Embodiment 8 is the process of embodiment 6 or 7, wherein the leaching is carried out at a temperature ranging from about 50° C. to about 150° C. Embodiment 9 is the process of any one of embodiments 6 to 8, wherein the leaching is carried out for a period ranging from about 15 minutes to about 16 hours. Embodiment 10 is the process of embodiment 3, wherein the flocculant comprises a carbonaceous binder. Embodiment 11 is the process of embodiment 10, wherein the carbonaceous binder is at least one of lignin, starch, modified starch, amylopectin, modified amylopectin, amylose, modified amylose, chitosan, chitin, guar gum, modified guar gum, cellulose, modified cellulose, and polyvinyl acetate (PVA). Embodiment 12 is the process of embodiment 3, wherein the flocculant comprises an organic resin binder material.Embodiment 13 is the process of embodiment 12, wherein the organic resin binder material is at least one of petroleum or coal tar pitch. Embodiment 14 is the process of any one of embodiments 1-13, wherein the reaction with the chlorine-containing gas is carried out at a temperature ranging from about 800° C. to about 1800° C.; Embodiment 15 is the process of any one of embodiments 1-14, wherein the reaction with the chlorine-containing gas is carried out for a period ranging from about 10 minutes to about 8 hours; Embodiment 16 is the process of any one of embodiments 1-15, wherein the particulate graphite feed is at least one of synthetic graphite, mined natural flake graphite (NFG), or graphite recovered from spent LiBs; Embodiment 17 is the process of any one of embodiments 1-16, further comprising grinding the purified particulate graphite material to a particle size ranging from about 5 to about 30 micrometers. Embodiment 18 is the process of any one of embodiments 1-17, wherein the purified particulate graphite material comprises a carbonized coating. Embodiment 19 is the process of any one of embodiments 1-18, wherein the purified particulate graphite material comprises a purity of greater than 99.95 wt.% C. Embodiment 20 is the process of embodiment 4, further comprising recycling the quenched chlorine-containing gas back to the process. Embodiment 21 is the process of embodiment 6, further comprising recycling the NaOH or KOH solution back to the process. Embodiment 22 is the process of embodiment 21, wherein the NaOH or KOH solution is neutralized to produce a NaCl or KCl solution. Embodiment 23 is the process of any one of embodiments 20-22, wherein the recycling comprises the use of a chloralkali system.

[0022] Embodiment 24 is a process for purifying graphite, the process comprising treating a particulate graphite feed with a flocculating agent to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising the purified agglomerated particulate graphite material and a chlorine-containing gas laden with chlorinated impurities, and separating the purified agglomerated particulate graphite material from the mixture.Embodiment 25 is the process of embodiment 24, further comprising leaching the particulate graphite feed with an alkaline leach solution to produce a slurry, and subjecting the slurry to a separation step, where the leaching is performed prior to treating with the flocculating agent.Embodiment 26 is the process of embodiment 24 or 25, where the chlorinated impurities laden chlorine-containing gas is quenched to remove impurities.Embodiment 27 is the process of embodiment 26, where the chlorinated impurities comprise metal chlorides. Embodiment 28 is the process of embodiment 25, wherein the leaching is carried out using an aqueous NaOH solution or an aqueous KOH solution. Embodiment 29 is the process of embodiment 28, wherein the aqueous NaOH solution comprises about 10% to about 50% NaOH by weight. Embodiment 30 is the process of embodiment 25, 28, or 29, wherein the leaching is carried out at a temperature ranging from about 50° C. to about 150° C. Embodiment 31 is the process of embodiment 25, 28, 29, or 30, wherein the leaching is carried out for a period ranging from about 15 minutes to about 16 hours. Embodiment 32 is the process of any one of embodiments 24 to 31, wherein the flocculant comprises a carbonaceous binder. Embodiment 33 is the process of embodiment 32, wherein the carbonaceous binder is at least one of lignin, starch, modified starch, amylopectin, modified amylopectin, amylose, modified amylose, chitosan, chitin, guar gum, modified guar gum, cellulose, modified cellulose, and polyvinyl acetate (PVA).Embodiment 34 is the process of any one of embodiments 24 to 31, wherein the flocculant comprises an organic resin material.Embodiment 35 is the process of embodiment 34, wherein the organic resin material is at least one of petroleum or coal tar pitch. Embodiment 36 is the process of any one of embodiments 24-35, wherein the reaction with the chlorine-containing gas is carried out at a temperature ranging from about 800° C. to about 1800° C.; Embodiment 37 is the process of any one of embodiments 24-36, wherein the reaction with the chlorine-containing gas is carried out for a period ranging from about 10 minutes to about 8 hours; Embodiment 38 is the process of any one of embodiments 24-37, wherein the particulate graphite feed is at least one of synthetic graphite, mined natural flake graphite (NFG), or graphite recovered from spent LiBs; Embodiment 39 is the process of any one of embodiments 24-38, further comprising grinding the purified agglomerated particulate graphite material to a particle size ranging from about 5 to about 30 micrometers. Embodiment 40 is the process of any one of embodiments 24-39, wherein the purified agglomerated particulate graphite material comprises a carbonized coating. Embodiment 41 is the process of any one of embodiments 24-40, wherein the purified agglomerated particulate graphite material comprises a purity of greater than 99.95 wt.% C. Embodiment 42 is the process of embodiment 26 or 27, further comprising recycling the quenched chlorine-containing gas back to the process. Embodiment 43 is the process of embodiment 28, further comprising recycling the NaOH or KOH solution back to the process. Embodiment 44 is the process of embodiment 43, wherein the NaOH or KOH solution is neutralized to produce a NaCl or KCl solution. Embodiment 45 is the process of any one of embodiments 42-44, wherein the recycling comprises the use of a chloralkali system.

[0023] Embodiment 46 is a process for purifying graphite, the process comprising leaching a particulate graphite feed using an alkaline leach solution to produce a leached graphite feed material, treating the leached graphite feed with a flocculating agent to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising the purified agglomerated particulate graphite material and a chlorine-containing gas enriched in chlorinated impurities, and separating the purified agglomerated particulate graphite material from the mixture. Embodiment 47 is the process of embodiment 46, wherein the chlorinated impurity enriched chlorine-containing gas is quenched to remove impurities. Embodiment 48 is the process of embodiment 47, wherein the chlorinated impurities comprise metal chlorides. Embodiment 49 is the process of any one of embodiments 45-48, wherein the leaching is performed using an aqueous NaOH solution or an aqueous KOH solution. Embodiment 50 is the process of embodiment 49, wherein the aqueous NaOH solution comprises about 10% to about 50% NaOH by weight. Embodiment 51 is the process of any one of embodiments 46 to 50, wherein the leaching is carried out at a temperature ranging from about 50° C. to about 150° C. Embodiment 52 is the process of any one of embodiments 46 to 51, wherein the leaching is carried out for a period ranging from about 15 minutes to about 16 hours. Embodiment 53 is the process of any one of embodiments 46 to 52, wherein the flocculating agent comprises a carbonaceous binder. Embodiment 54 is the process of embodiment 53, wherein the carbonaceous binder is at least one of lignin, starch, modified starch, amylopectin, modified amylopectin, amylose, modified amylose, chitosan, chitin, guar gum, modified guar gum, cellulose, modified cellulose, and polyvinyl acetate (PVA). Embodiment 55 is the process of any one of embodiments 46-52, wherein the flocculant comprises an organic resin material.Embodiment 56 is the process of embodiment 55, wherein the organic resin material is at least one of a petroleum or coal tar pitch.Embodiment 57 is the process of any one of embodiments 46-56, wherein the reaction with the chlorine-containing gas is carried out at a temperature ranging from about 800° C. to about 1800° C.; and embodiment 58 is the process of any one of embodiments 46-57, wherein the reaction with the chlorine-containing gas is carried out for a period ranging from about 10 minutes to about 8 hours. Embodiment 59 is the process of any one of embodiments 46-58, wherein the particulate graphite feed is at least one of synthetic graphite, mined natural flake graphite (NFG), or graphite recovered from spent LiBs. Embodiment 60 is the process of any one of embodiments 46-59, further comprising grinding the purified agglomerated particulate graphite material to a particle size ranging from about 5 to about 30 micrometers. Embodiment 61 is the process of any one of embodiments 46-60, wherein the purified agglomerated particulate graphite material includes a carbonized coating. Embodiment 62 is the process of any one of embodiments 46-61, wherein the purified agglomerated particulate graphite material comprises a purity of greater than 99.95 wt.% C. Embodiment 63 is the process of embodiment 47 or 48, further comprising recycling the quenched chlorine-containing gas back to the process. Embodiment 64 is the process of embodiment 49, further comprising recycling the NaOH or KOH solution back to the process. Embodiment 65 is the process of embodiment 64, wherein the NaOH or KOH solution is neutralized to produce a NaCl or KCl solution. Embodiment 66 is the process of any one of embodiments 63-65, wherein the recycling comprises the use of a chloralkali system.

[0024] Embodiment 67 is a process for purifying graphite, the process comprising reacting a particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising purified particulate graphite material and a chlorine-containing gas laden with chlorinated impurities, and separating the purified particulate graphite material from the mixture. Embodiment 68 is the process of embodiment 67, further comprising leaching the particulate graphite feed using an alkaline leach solution to produce a slurry, and subjecting the slurry to a separation step, where the leaching is preformed prior to reacting with the chlorine-containing gas. Embodiment 69 is the process of embodiment 67 or 68, further comprising agglomerating the particulate graphite feed using mechanical means. Embodiment 70 is the process of any one of embodiments 67-69, where the chlorinated impurities laden with chlorine-containing gas is quenched to remove the impurities. Embodiment 71 is the process of embodiment 70, where the chlorinated impurities comprise metal chlorides. Embodiment 72 is the process of embodiment 68, wherein the leaching is carried out using an aqueous NaOH solution or an aqueous KOH solution. Embodiment 73 is the process of embodiment 72, wherein the aqueous NaOH solution comprises about 10% to about 50% NaOH by weight. Embodiment 74 is the process of embodiment 72 or 73, wherein the leaching is carried out at a temperature ranging from about 50° C. to about 150° C. Embodiment 75 is the process of any one of embodiments 72-74, wherein the leaching is carried out for a period ranging from about 15 minutes to about 16 hours. Embodiment 76 is the process of embodiment 69, wherein the mechanical means comprises mechanical briquetting. Embodiment 77 is the process of any one of embodiments 67-76, wherein the reaction with the chlorine-containing gas is carried out at a temperature ranging from about 800° C. to about 1800° C. Embodiment 78 is the process of any one of embodiments 67-77, wherein the reaction with the chlorine-containing gas is carried out for a period ranging from about 10 minutes to about 8 hours.Embodiment 79 is the process of any one of embodiments 67-78, wherein the particulate graphite feed is at least one of synthetic graphite, mined natural flake graphite (NFG), or graphite recovered from spent LiBs. Embodiment 80 is the process of any one of embodiments 67-79, further comprising grinding the purified particulate graphite material to a particle size ranging from about 5 to about 30 micrometers. Embodiment 81 is the process of any one of embodiments 67-80, wherein the purified particulate graphite material comprises a purity of greater than 99.95 wt.% C. Embodiment 82 is the process of embodiment 70, further comprising recycling the quenched chlorine-containing gas back to the process. Embodiment 83 is the process of embodiment 72, further comprising recycling the NaOH or KOH values ​​back to the process. Embodiment 84 is the process of embodiment 83, wherein the NaOH or KOH solution is neutralized to produce a NaCl or KCl solution. Embodiment 85 is the process of any one of embodiments 82-84, wherein the recycling comprises the use of a chloralkali system.Embodiment 86 is the process of any one of embodiments 67-85, further comprising carbon coating the purified particulate graphite material.

[0025] Embodiment 87 is a process for purifying graphite, the process comprising agglomerating a particulate graphite feed using mechanical means to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising the purified agglomerated particulate graphite material and a chlorine-containing gas enriched in chlorinated impurities, and separating the purified agglomerated particulate graphite material from the mixture.Embodiment 88 is the process of embodiment 87, further comprising leaching the particulate graphite feed using an alkaline leach solution to produce a slurry, and subjecting the slurry to a separation step, where the leaching is performed prior to the agglomeration step.Embodiment 89 is the process of embodiment 87 or 88, where the chlorinated impurities enriched chlorine-containing gas is quenched to remove impurities.Embodiment 90 is the process of embodiment 89, where the chlorinated impurities comprise metal chlorides. Embodiment 91 is the process of embodiment 88, wherein the leaching is carried out using an aqueous NaOH solution or an aqueous KOH solution. Embodiment 92 is the process of embodiment 91, wherein the aqueous NaOH solution comprises about 10% to about 50% NaOH by weight. Embodiment 93 is the process of embodiment 88, 91, or 92, wherein the leaching is carried out at a temperature ranging from about 50° C. to about 150° C. Embodiment 94 is the process of embodiment 88, 91, 92, or 93, wherein the leaching is carried out for a period ranging from about 15 minutes to about 16 hours. Embodiment 95 is the process of any one of embodiments 87-94, wherein the mechanical means comprises mechanical briquetting. Embodiment 96 is the process of any one of embodiments 87-95, wherein the reaction with the chlorine-containing gas is carried out at a temperature ranging from about 800° C. to about 1800° C. Embodiment 97 is the process of any one of embodiments 87-96, wherein the reaction with the chlorine-containing gas is carried out for a period ranging from about 10 minutes to about 8 hours.Embodiment 98 is the process of any one of embodiments 87-97, wherein the particulate graphite feed is at least one of synthetic graphite, mined natural flake graphite (NFG), or graphite recovered from spent LiBs. Embodiment 99 is the process of any one of embodiments 87-98, further comprising grinding the purified agglomerated particulate graphite material to a particle size ranging from about 5 to about 30 micrometers. Embodiment 100 is the process of any one of embodiments 87-99, wherein the purified agglomerated particulate graphite material comprises a purity of greater than 99.95 wt.% C. Embodiment 101 is the process of embodiment 89 or 90, further comprising recycling the quenched chlorine-containing gas back to the process. Embodiment 102 is the process of embodiment 91, further comprising recycling the NaOH or KOH values ​​back to the process. Embodiment 103 is the process of embodiment 102, wherein the NaOH or KOH solution is neutralized to produce a NaCl or KCl solution.Embodiment 104 is the process of any one of embodiments 101-103, wherein the recycling comprises the use of a chloralkali system.Embodiment 105 is the process of any one of embodiments 87-104, further comprising carbon coating the purified particulate graphite material.

[0026] Embodiment 106 is a process for purifying graphite, the process comprising leaching a particulate graphite feed using an alkaline leach solution to produce a leached graphite feed material, agglomerating the leached graphite feed using mechanical means to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising the purified agglomerated particulate graphite material and a chlorine-containing gas enriched in chlorinated impurities, and separating the purified agglomerated particulate graphite material from the mixture. Embodiment 107 is the process of embodiment 106, wherein the chlorinated impurity enriched chlorine-containing gas is quenched to remove impurities. Embodiment 108 is the process of embodiment 107, wherein the chlorinated impurities comprise metal chlorides. Embodiment 109 is the process of any one of embodiments 106-108, wherein the leaching is performed using an aqueous NaOH solution or an aqueous KOH solution. Embodiment 110 is the process of embodiment 109, wherein the aqueous NaOH solution comprises about 10% to about 50% NaOH by weight. Embodiment 111 is the process of any one of embodiments 106-110, wherein the leaching is carried out at a temperature ranging from about 50° C. to about 150° C.; Embodiment 112 is the process of any one of embodiments 106-111, wherein the leaching is carried out for a period ranging from about 15 minutes to about 16 hours; Embodiment 113 is the process of any one of embodiments 106-112, wherein the reaction with the chlorine-containing gas is carried out at a temperature ranging from about 800° C. to about 1800° C.; Embodiment 114 is the process of any one of embodiments 106-113, wherein the reaction with the chlorine-containing gas is carried out for a period ranging from about 10 minutes to about 8 hours. Embodiment 115 is the process of any one of embodiments 106-114, wherein the particulate graphite feed is at least one of synthetic graphite, mined natural flake graphite (NFG), or graphite recovered from spent LiBs.Embodiment 116 is the process of any one of embodiments 106-115, further comprising grinding the purified agglomerated particulate graphite material to a particle size ranging from about 5 to about 30 micrometers. Embodiment 117 is the process of any one of embodiments 106-116, wherein the purified agglomerated particulate graphite material comprises a purity of greater than 99.95 wt.% C. Embodiment 118 is the process of embodiment 107 or 108, further comprising recycling the quenched chlorine-containing gas back to the process. Embodiment 119 is the process of embodiment 109, further comprising recycling the NaOH or KOH solution back to the process. Embodiment 120 is the process of embodiment 119, wherein the NaOH or KOH solution is neutralized to produce a NaCl or KCl solution. Embodiment 121 is the process of any one of embodiments 118-120, wherein the recycling comprises the use of a chloralkali system. Embodiment 122 is the process of any one of embodiments 106-121, further comprising carbon coating the purified particulate graphitic material.Embodiment 123 is the process of any one of embodiments 106-122, wherein the mechanical means comprises mechanical briquetting.

[0027] Embodiment 124 is a particulate graphite material comprising a purity of greater than 99.95 wt.% C. Embodiment 125 is a particulate graphite material according to embodiment 124, comprising a coated surface. Embodiment 126 is a particulate graphite material according to embodiment 125, wherein the coating is a carbonized coating. Embodiment 127 is a particulate graphite material according to embodiment 126, wherein the carbonized coating is produced from a binder material. Embodiment 128 is a particulate graphite material according to embodiment 127, wherein the binder material is at least one of a carbonaceous binder or an organic resin material. Embodiment 129 is a particulate graphite material according to embodiment 128, wherein the carbonaceous binder is at least one of lignin, starch, modified starch, amylopectin, modified amylopectin, amylose, modified amylose, chitosan, chitin, guar gum, modified guar gum, cellulose, modified cellulose, and polyvinyl acetate (PVA). Embodiment 130 is the particulate graphite material of embodiment 128, wherein the organic resin material is at least one of petroleum or coal tar pitch. Embodiment 131 is the particulate graphite material of any one of embodiments 124-130, comprising a particle size ranging from about 5 to about 30 micrometers. Embodiment 132 is the particulate graphite material of any one of embodiments 124-131, wherein the graphite material is sourced from at least one of synthetic graphite or mined natural flake graphite (NFG). Embodiment 133 is the particulate graphite material of any one of embodiments 124-132, obtained or obtainable by the process of any one of embodiments 1-66. Embodiment 134 is the particulate graphite material of embodiment 124, obtained or obtainable by the process of any one of embodiments 67-123. Embodiment 135 is the particulate graphite material of any one of embodiments 124-134, wherein the material comprises spheroidized material.

[0028] Embodiment 136 is an anode material for a lithium ion battery (LiB) comprising a particulate graphite material having a purity of greater than 99.95 wt.% C. Embodiment 137 is an anode material according to embodiment 136, wherein the particulate graphite material comprises a carbonized coating material. Embodiment 138 is an anode material according to embodiment 137, wherein the carbonized coating is formed from a binder material. Embodiment 139 is an anode material according to embodiment 138, wherein the binder material is at least one of a carbonaceous binder or an organic resin material. Embodiment 140 is an anode material according to embodiment 139, wherein the carbonaceous binder is at least one of lignin, starch, modified starch, amylopectin, modified amylopectin, amylose, modified amylose, chitosan, chitin, guar gum, modified guar gum, cellulose, modified cellulose, and polyvinyl acetate (PVA). Embodiment 141 is the anode material of embodiment 139, wherein the organic resin material is at least one of petroleum or coal tar pitch. Embodiment 142 is the anode material of any one of embodiments 136-141, wherein the particle size ranges from about 5 to about 30 micrometers. Embodiment 143 is the anode material of any one of embodiments 136-142, wherein the graphite material is sourced from at least one of synthetic graphite or mined natural flake graphite (NFG). Embodiment 144 is the anode material of any one of embodiments 136-143, wherein the anode material is obtained or obtainable by the process of any one of embodiments 1-66.

[0029] Embodiment 145 is a graphite particle for a lithium ion battery (LiB), the graphite particle having a purity of greater than 99.95 wt% C, and a calcined binder material is attached to at least a portion of the surface of the graphite particle.Embodiment 146 is the graphite particle of embodiment 145, the binder material is at least one of a carbonaceous binder or an organic resin material.Embodiment 147 is the graphite particle of embodiment 146, the carbonaceous binder is at least one of lignin, starch, modified starch, amylopectin, modified amylopectin, amylose, modified amylose, chitosan, chitin, guar gum, modified guar gum, cellulose, modified cellulose, and polyvinyl acetate (PVA).Embodiment 148 is the graphite particle of embodiment 146, the organic resin material is at least one of petroleum or coal tar pitch. Embodiment 148 is the graphite particle of any one of embodiments 145-148, comprising a particle size ranging from about 5 to about 30 micrometers. Embodiment 150 is the graphite particle of any one of embodiments 145-149, wherein the graphite is sourced from at least one of synthetic graphite or mined natural flake graphite (NFG). Embodiment 151 is the graphite particle of any one of embodiments 145-150, obtained or obtainable by the process of any one of embodiments 1-66.

[0030] Embodiment 152 is an electrode or electrochemical storage device comprising the particulate graphite material of any one of embodiments 124-132.

[0031] Embodiment 153 is an electrode or electrochemical storage device comprising the anode material of any one of embodiments 136-143.

[0032] Embodiment 154 is an electrode or an electrochemical storage device comprising the graphite particles of any one of embodiments 145 to 150. Embodiment 155 is an electrode or an electrochemical storage device of any one of embodiments 152 to 154, wherein the electrochemical storage device comprises a lithium ion battery (LiB).

[0033] The words "a" or "an," when used in conjunction with the term "comprising" in the claims and / or specification, may mean "one," but it is also consistent with the meanings of "one or more," "at least one," and "one or more," unless the content clearly dictates otherwise. Similarly, the word "another" may mean at least a second or more, unless the content clearly dictates otherwise.

[0034] As used in the specification and claim(s), the words "comprising" (and any form of including, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "include" and "includes"), or "containing" (and any form of containing, such as "contain" and "contains") are inclusive or open-ended and do not exclude additional, unrecited elements or process steps.

[0035] As used in this specification and claim(s), the word "consisting of" and its derivatives are intended to be close-ended terms specifying the presence of stated features, elements, components, groups, elements, and / or steps, and excluding the presence of other unrecited features, elements, components, groups, elements, and / or steps.

[0036] As used herein, the term "consisting essentially of" is intended to specify the presence of a stated feature, element, component, group, element, and / or step, and that does not materially affect the basic and novel characteristic(s) of that feature, element, component, group, element, and / or step.

[0037] As used herein, the terms "about," "substantially," and "approximately" refer to a reasonable amount of deviation from the modified term so that the end result is not significantly altered. These terms of degree should be interpreted as including deviations of at least ±5% of the modified term if this deviation does not negate the meaning of the word it modifies.

[0038] The foregoing and other advantages and features of the present disclosure will become more apparent upon reading the following non-limiting detailed description of exemplary embodiments thereof, with reference to the accompanying drawings / figures. It should be understood, however, that the detailed description and exemplary embodiments, while indicating particular embodiments of the present disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the present disclosure will become apparent to those skilled in the art from this description.

[0039] The following figures / drawings form part of the present specification and are included to further demonstrate certain aspects of the present specification. The specification may be better understood by reference to one or more of these figures / drawings in combination with the detailed description. The accompanying figures / drawings are as follows: [Brief description of the drawings]

[0040] [Figure 1] FIG. 1 is an illustration of a flow chart illustrating a process for purifying and producing high purity particulate graphite material from a graphite feed material according to one embodiment of the present disclosure. [Diagram 2] FIG. 1 is an illustration of a flow chart illustrating a process for purifying and producing high purity particulate graphite material from a graphite feed material according to one embodiment of the present disclosure. [Diagram 3] FIG. 1 is an illustration of a flow chart illustrating a process for purifying and producing high purity particulate graphite material from a graphite feed material according to one embodiment of the present disclosure. [Figure 4] FIG. 1 is an illustration of a flow chart illustrating a process for purifying and producing high purity particulate graphite material from a graphite feed material according to one embodiment of the present disclosure. [Diagram 5] FIG. 1 is an illustration of a flow chart illustrating a process for purifying and producing high purity particulate graphite material from a graphite feed material according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] The present disclosure relates to a process for purifying and producing high purity graphite particles suitable for use in batteries. The present disclosure also relates to a process for purifying and producing coated high purity graphite particles suitable for use in batteries. In one aspect of the present disclosure, the coating comprises a carbon coating. The present disclosure also relates to high purity particulate graphite particles and their use as an anode material in rechargeable lithium ion batteries (LiBs). The present disclosure also relates to coated high purity particulate graphite particles and their use as an anode material in rechargeable lithium ion batteries (LiBs). In one aspect of the present disclosure, the coating comprises a carbon coating. In one aspect of the present disclosure, the high purity graphite particles exhibit a purity of greater than 99.95 wt.% C. These and other aspects of the present disclosure are described in further detail below.

[0042] Referring to Figure 1, selected steps of a process for purifying and producing coated high purity particulate graphite material from a graphite feed material are illustrated therein in accordance with an embodiment of the present disclosure. The process includes treating an impure graphite feed with an agglomerating agent to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture including purified agglomerated particulate graphite material and a chlorine-containing gas rich in chlorinated impurities, separating the purified agglomerated particulate graphite material from the gaseous mixture, quenching the gaseous mixture to condense and separate the impurities from the chlorine gas as a metal chloride solution, reacting the chlorine gas with hydrogen to form hydrochloric acid, and crushing the agglomerates to obtain coated purified particulate graphite material. In one aspect of the present disclosure, the coating includes a carbon coating.

[0043] Referring to Figure 2, selected steps of a process for purifying and producing coated high purity particulate graphite material from a graphite feed material are illustrated therein according to an embodiment of the present disclosure. The process includes treating an impure graphite feed with an agglomerating agent to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture including purified agglomerated particulate graphite material and a chlorine-containing gas rich in chlorinated impurities, oxidizing the chlorinated impurities using oxygen (as practiced in the production of titanium oxide in the pigment industry) to produce a solid particulate oxide, separating the solid oxide from the chlorine gas, washing, drying and compressing the chlorine gas prior to recycling it back to the chlorination reactor, and crushing the agglomerates to obtain a coated purified particulate graphite material. In one aspect of the present disclosure, the coating includes a carbon coating.

[0044] Referring to Figure 3, selected steps of a process for purifying and producing a coated high purity particulate graphite material from a graphite feed material are illustrated therein according to an embodiment of the present disclosure. The process includes leaching a non-pure particulate graphite feed using an alkaline leach solution to produce a partially purified leached particulate graphite feed material, treating the partially purified leached particulate graphite feed with a flocculating agent to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture including the purified agglomerated particulate graphite material and a chlorinated impurity-rich chlorine-containing gas, separating the purified agglomerated particulate graphite material from the gaseous mixture, quenching the gaseous mixture to condense and separate the impurities from the chlorine gas as a metal chloride solution, reacting the chlorine gas with hydrogen to form hydrochloric acid, and crushing the agglomerates to obtain a coated purified particulate graphite material. In one aspect of the present disclosure, the coating includes a carbon coating.

[0045] Referring to FIG. 4, selected steps of a process for purifying and producing coated high purity particulate graphite material from a graphite feed material according to an embodiment of the present disclosure are illustrated therein. The process includes leaching a non-pure particulate graphite feed using an alkaline leach solution to produce a partially purified leached particulate graphite feed material, treating the partially purified leached particulate graphite feed with a flocculating agent to produce an agglomerated particulate graphite feed, reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture including the purified agglomerated particulate graphite material and a chlorine-containing gas rich in chlorinated impurities, separating the purified agglomerated particulate graphite material from the gaseous mixture, quenching the gaseous mixture to condense and separate the impurities from the chlorine gas as a metal chloride solution, reacting the chlorine gas with hydrogen to form hydrochloric acid, neutralizing the hydrochloric acid with the spent alkaline leach solution to produce an alkali metal salt solution, purifying the alkali metal salt solution using a precipitation reagent, producing an alkaline leach solution and chlorine using an industry standard chlor-alkali process, and crushing the agglomerates to obtain a coated purified particulate graphite material. In one aspect of the present disclosure, the coating comprises a carbon coating.

[0046] Referring to FIG. 5, selected steps of a process for purifying and producing coated high purity particulate graphite material from a graphite feed material according to an embodiment of the present disclosure are illustrated therein. The process includes leaching a non-pure particulate graphite feed using an alkaline leach solution to produce a partially purified leached particulate graphite feed material; agglomerating the partially purified leached particulate graphite feed with or without a flocculating agent using mechanical briquetting to produce an agglomerated particulate graphite feed; reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture including the purified agglomerated particulate graphite material and a chlorinated impurity-rich chlorine-containing gas; separating the purified agglomerated particulate graphite material from the gaseous mixture; quenching the gaseous mixture to condense and separate the impurities from the chlorine gas as a metal chloride solution; reacting the chlorine gas with hydrogen to form hydrochloric acid; neutralizing the hydrochloric acid with the spent alkaline leach solution to produce an alkali metal salt solution; purifying the alkali metal salt solution using a precipitation reagent; producing an alkaline leach solution and chlorine using an industry standard chlor-alkali process; and crushing the agglomerates to obtain a coated purified particulate graphite material. In one aspect of the present disclosure, when the mechanical briquetting is performed in the absence of a flocculant, the refined particulate graphitic material is uncoated. In one aspect of the present disclosure, when the mechanical briquetting is performed in the presence of a flocculant, the refined particulate graphitic material is coated. In a further aspect of the present disclosure, the coating comprises a carbon coating.

[0047] It is to be understood that although the processes and process steps described herein are designed to produce high purity particulate graphite material for use in lithium ion batteries (LiBs), the processes and process steps can also be used to purify any carbonaceous material, including, by way of non-limiting examples, synthetic graphite and amorphous carbon. In one embodiment of the present disclosure, such a carbonaceous material is graphite recovered from spent LiBs.

[0048] In one embodiment of the present disclosure, the graphite feed material consists of natural flake graphite (NFG). The impurities contained in NFG are typically classified into two broad groups: species that react more readily under alkaline conditions, such as by treatment with aqueous NaOH or KOH (e.g., silicates), and species that react more readily with chlorine gas to form volatile chlorides (e.g., metal oxides). Thus, the process for producing high purity particulate graphite material can be tailored depending on the impurity composition of the graphite feed material. In embodiments where the graphite feed material contains both silicate and metal oxide impurities, the process may advantageously include both a leaching step and a chlorination step. In embodiments where the graphite feed material contains substantially metal oxide impurities, the leaching step may be omitted and the graphite feed material is subjected only to the chlorination step, as illustrated in Figures 1 and 2.

[0049] In one aspect of the disclosure, the graphite feed material may be subjected to a leaching process using an alkaline leach solution, as illustrated in FIGS. 3 and 4. In one embodiment of the disclosure, the alkaline leach solution comprises an aqueous NaOH solution or an aqueous KOH solution. The alkaline leaching dissolves and removes some of the impurities present in the graphite feed material, non-limiting examples of which include silicates, in the leach solution. The leach solution may then be separated from the leached graphite feed material via decantation and / or filtration, and neutralized to provide a partially purified fine particulate graphite feed material. In some embodiments, the precipitate may be further subjected to one or more washes (e.g., with water). In some embodiments, the leach solution may be neutralized using hydrochloric acid. Neutralization results in the formation (e.g., precipitation) of a solid residue substantially composed of impurities contained in the original graphite feed material (e.g., silicates). The solid residue may then be separated from the neutralized liquor via decantation and / or filtration. In some embodiments, the solid residue is disposed of. In one aspect of the present disclosure, the neutralized liquid, which contains primarily sodium chloride (NaCl) or potassium chloride (KCl), can be purified using precipitation techniques standard in the chloralkali process industry and recycled as feed to the chloralkali system for further production of NaOH or KOH solution, and Cl2 gas.

[0050] In an embodiment of the present disclosure, the alkaline leach solution is from about 10% to about 50% NaOH by weight, in a further embodiment from about 15% to about 45% NaOH by weight, in a further embodiment from about 20% to about 40% NaOH by weight, in a further embodiment from about 25% to about 35% NaOH by weight, in a further embodiment from about 10% to about 45% NaOH by weight, in a further embodiment from about 10% to about 40% NaOH by weight, in a further embodiment from about 10% to about 35% NaOH by weight, in a further embodiment from about 10% to about 30% NaOH by weight, in a further embodiment In a further embodiment, about 10% to about 25% by weight NaOH, in a further embodiment, about 10% to about 20% by weight NaOH, in a further embodiment, about 10% to about 15% by weight NaOH, in a further embodiment, about 15% to about 50% by weight NaOH, in a further embodiment, about 20% to about 50% by weight NaOH, in a further embodiment, about 25% to about 50% by weight NaOH, in a further embodiment, about 30% to about 50% by weight NaOH, in a further embodiment, about 35% to about 50% by weight NaOH, in a further embodiment, about 40% to about 50% by weight NaOH. aOH, about 10% by weight NaOH, about 11% by weight NaOH, about 12% by weight NaOH, about 13% by weight NaOH, about 14% by weight NaOH, about 15% by weight NaOH, about 16% by weight NaOH, about 17% by weight NaOH, about 18% by weight NaOH, about 19% by weight NaOH, about 20% by weight NaOH, about 21% by weight NaOH, about 22% by weight NaOH, about 23% by weight NaOH, about 24% by weight NaOH, about 25% by weight NaOH, about 26% by weight NaOH, about 27% by weight NaOH, about 28% by weight NaOH, about 29% by weight NaOH, about 30% by weight % NaOH, about 31% NaOH, about 32% NaOH, about 33% NaOH, about 34% NaOH, about 35% NaOH, about 36% NaOH, about 37% NaOH, about 38% NaOH, about 39% NaOH, about 40% NaOH, about 41% NaOH, about 42% NaOH, about 43% NaOH, about 44% NaOH, about 45% NaOH, about 46% NaOH, about 47% NaOH, about 48% NaOH, about 49% NaOH, or about 50% NaOH by weight.

[0051] In an embodiment of the present disclosure, the alkaline leach solution is from about 10% to about 50% KOH by weight, in a further embodiment from about 15% to about 45% KOH by weight, in a further embodiment from about 20% to about 40% KOH by weight, in a further embodiment from about 25% to about 35% KOH by weight, in a further embodiment from about 10% to about 45% KOH by weight, in a further embodiment from about 10% to about 40% KOH by weight, in a further embodiment from about 10% to about 35% KOH by weight, in a further embodiment from about 10% to about 30% KOH by weight, In further embodiments, about 10% to about 25% KOH by weight, in further embodiments, about 10% to about 20% KOH by weight, in further embodiments, about 10% to about 15% KOH by weight, in further embodiments, about 15% to about 50% KOH by weight, in further embodiments, about 20% to about 50% KOH by weight, in further embodiments, about 25% to about 50% KOH by weight, in further embodiments, about 30% to about 50% KOH by weight, in further embodiments, about 35% to about 50% KOH by weight, in further embodiments, about 40% to about 50% KOH by weight, in further embodiments, about 4 ... 0% to about 50% by weight KOH, about 10% by weight KOH, about 11% by weight KOH, about 12% by weight KOH, about 13% by weight KOH, about 14% by weight KOH, about 15% by weight KOH, about 16% by weight KOH, about 17% by weight KOH, about 18% by weight KOH, about 19% by weight KOH, about 20% by weight KOH, about 21% by weight KOH, about 22% by weight KOH, about 23% by weight KOH, about 24% by weight KOH, about 25% by weight KOH, about 26% by weight KOH, about 27% by weight KOH, about 28% by weight KOH, about 29% by weight KOH, The KOH may be about 30% by weight, about 31% by weight, about 32% by weight, about 33% by weight, about 34% by weight, about 35% by weight, about 36% by weight, about 37% by weight, about 38% by weight, about 39% by weight, about 40% by weight, about 41% by weight, about 42% by weight, about 43% by weight, about 44% by weight, about 45% by weight, about 46% by weight, about 47% by weight, about 48% by weight, about 49% by weight, or about 50% by weight.

[0052] In an embodiment of the present disclosure, the alkaline leaching is performed at a temperature between about 50°C and about 150°C, in a further embodiment between about 55°C and about 145°C, in a further embodiment between about 60°C and about 140°C, in a further embodiment between about 65°C and about 135°C, in a further embodiment between about 70°C and about 130°C, in a further embodiment between about 75°C and about 125°C, in a further embodiment between about 80°C and about 120°C, in a further embodiment between about 85°C and about 115°C, and in a further embodiment between about 90°C and about 125°C. 0°C to about 110°C, in a further embodiment, about 95°C to about 105°C, in a further embodiment, about 55°C to about 150°C, in a further embodiment, about 60°C to about 150°C, in a further embodiment, about 65°C to about 150°C, in a further embodiment, about 70°C to about 150°C, in a further embodiment, about 75°C to about 150°C, in a further embodiment, about 80°C to about 150°C, in a further embodiment, about 85°C to about 150°C, in a further embodiment, about 90°C to about 150°C, ℃ to about 150 ° C, in a further embodiment, about 95 ° C to about 150 ° C, in a further embodiment, about 100 ° C to about 150 ° C, in a further embodiment, about 105 ° C to about 150 ° C, in a further embodiment, about 110 ° C to about 150 ° C, in a further embodiment, about 115 ° C to about 150 ° C, in a further embodiment, about 120 ° C to about 150 ° C, in a further embodiment, about 125 ° C to about 150 ° C, in a further embodiment, about 130 ° C to about 150 ° C, in a further embodiment In a further embodiment, the reaction may be carried out at a temperature range of about 135°C to about 150°C, in a further embodiment, about 140°C to about 150°C, in a further embodiment, about 145°C to about 150°C, about 50°C, about 55°C, about 60°C, about 65°C, about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, about 95°C, about 100°C, about 105°C, about 110°C, about 115°C, about 120°C, about 125°C, about 130°C, about 135°C, about 140°C, about 145°C, or about 150°C.

[0053] In an embodiment of the present disclosure, the alkaline leaching is performed for about 15 minutes to about 16 hours, and in a further embodiment, for about 30 minutes to about 16 hours, and in a further embodiment, for about 45 minutes to about 16 hours, and in a further embodiment, for about 1 hour to about 16 hours, and in a further embodiment, for about 1.5 hours to about 16 hours, and in a further embodiment, for about 2 hours to about 16 hours, and in a further embodiment, for about 2.5 hours to about 16 hours, and in a further embodiment, for about 3 hours to about 16 hours, and in a further embodiment, for about 3.5 hours to about 16 hours, and in a further embodiment, for about 4 hours to about 16 hours, and in a further embodiment, for about 4.5 hours to about 16 hours, and in a further embodiment, for about 5 hours to about 16 hours. In one embodiment, the reaction time is from about 5 hours to about 16 hours, and in a further embodiment, from about 5.5 hours to about 16 hours, and in a further embodiment, from about 6 hours to about 16 hours, and in a further embodiment, from about 6.5 hours to about 16 hours, and in a further embodiment, from about 7 hours to about 16 hours, and in a further embodiment, from about 7.5 hours to about 16 hours, and in a further embodiment, from about 8 hours to about 16 hours, and in a further embodiment, from about 8.5 hours to about 16 hours, and in a further embodiment, from about 9 hours to about 16 hours, and in a further embodiment, from about 9.5 hours to about 16 hours, and in a further embodiment, from about 10 hours to about 16 hours, about 10.5 hours to about 16 hours, in a further embodiment, about 11 hours to about 16 hours, in a further embodiment, about 11.5 hours to about 16 hours, in a further embodiment, about 12 hours to about 16 hours, in a further embodiment, about 12.5 hours to about 16 hours, in a further embodiment, about 13 hours to about 16 hours, in a further embodiment, about 13.5 hours to about 16 hours, in a further embodiment, about 14 hours to about 16 hours, in a further embodiment, about 14.5 hours to about 16 hours, in a further embodiment, about 15 hours to about 16 hours, in a further embodiment, about 15 minutes to about 15.5 hours, in a further embodiment In a further embodiment, the reaction time is from about 15 minutes to about 14 hours, and in a further embodiment, from about 15 minutes to about 13.5 hours, and in a further embodiment, from about 15 minutes to about 13 hours, and in a further embodiment, from about 15 minutes to about 12.5 hours, and in a further embodiment, from about 15 minutes to about 12 hours, and in a further embodiment, from about 15 minutes to about 11.5 hours, and in a further embodiment, from about 15 minutes to about 11 hours, and in a further embodiment, from about 15 minutes to about 10.5 hours, and in a further embodiment, from about 15 minutes to about 10 hours, and in a further embodiment, from about 15 minutes to about 9.5 hours, and in a further embodiment, from about 15 minutes to about 9 hours, and in a further embodiment, from about 15 minutes to about 8 hours.In a further embodiment, the reaction mixture is stirred for 5 hours, and in a further embodiment, from about 15 minutes to about 8 hours, and in a further embodiment, from about 15 minutes to about 7.5 hours, and in a further embodiment, from about 15 minutes to about 7 hours, and in a further embodiment, from about 15 minutes to about 6.5 hours, and in a further embodiment, from about 15 minutes to about 6 hours, and in a further embodiment, from about 15 minutes to about 5.5 hours, and in a further embodiment, from about 15 minutes to about 5 hours, and in a further embodiment, from about 15 minutes to about 4.5 hours, and in a further embodiment, from about 15 minutes to about 4 hours, and in a further embodiment, from about 15 minutes to about 3.5 hours, and in a further embodiment, from about 15 minutes to about 3 hours, and in a further embodiment, from about 15 minutes to about 2.5 hours, and in a further embodiment, from about 15 minutes to about 2 hours, and in a further embodiment, from about 15 minutes to about 1.5 hours In further embodiments, the reaction may be carried out for a period ranging from about 15 minutes to about 1 hour, in further embodiments, from about 15 minutes to about 45 minutes, and in further embodiments, from about 15 minutes to about 30 minutes, about 15 minutes, about 30 minutes, about 45 minutes, about 1 hour, about 1.5 hours, about 2 hours, about 2.5 hours, about 3 hours, about 3.5 hours, about 4 hours, about 4.5 hours, about 5 hours, about 5.5 hours, about 6 hours, about 6.5 hours, about 7 hours, about 7.5 hours, about 8 hours, about 8.5 hours, about 9 hours, about 9.5 hours, about 10 hours, about 10.5 hours, about 11 hours, about 11.5 hours, about 12 hours, about 12.5 hours, about 13 hours, about 13.5 hours, about 14 hours, about 14.5 hours, about 15 hours, about 15.5 hours, or about 16 hours.

[0054] In one aspect of the present disclosure, the partially purified leached particulate graphite feed may be subjected to a chlorination step using a chlorine-containing gas. In one embodiment of the present disclosure, the chlorination step advantageously removes additional impurities from the partially purified graphite feed material in the form of chlorinated impurities, non-limiting examples of which include metal chlorides. Metal chlorides include volatile metal chlorides such as FeCl3. The chlorinated impurities (e.g., metal chlorides) are then removed from the graphite material by flowing Cl2 gas. In one embodiment of the present disclosure, the chlorinated impurity-laden chlorine-containing gas may be quenched in water, and the chlorinated impurities are separated from the Cl2 gas by filtration and / or evaporation of the quenching aqueous solution. The quenching may be performed using a contacting device such as a wet scrubber. In one embodiment of the present disclosure, the chlorinated impurity-free Cl2 gas may then be combusted using hydrogen gas (H2) to form an aqueous hydrochloric acid solution, which may be used to neutralize the leachate from the leaching step. The chlorination step can be carried out using standard pyrometallurgical reactors, including, but not limited to, shaft furnaces, rotary kilns, Acheson furnaces, or fluidized bed reactors. The purified graphite material leaving the chlorination reactor is cooled and, if in agglomerated form, lightly crushed to reconstitute particulate material of appropriate particle size.

[0055] In an embodiment of the present disclosure, the chlorination step is carried out at a temperature of about 800°C to about 1800°C, in a further embodiment, about 850°C to about 1750°C, in a further embodiment, about 900°C to about 1700°C, in a further embodiment, about 950°C to about 1650°C, in a further embodiment, about 1000°C to about 1600°C, in a further embodiment, about 1050°C to about 1550°C, in a further embodiment, about 1100°C to about 1500°C, in a further embodiment, about 1150°C to about 1450°C, in a further embodiment, about 1200°C to about 1400°C, In a further embodiment, the temperature is from about 1250°C to about 1350°C, in a further embodiment, from about 1275°C to about 1325°C, in a further embodiment, from about 850°C to about 1800°C, in a further embodiment, from about 900°C to about 1800°C, in a further embodiment, from about 950°C to about 1800°C, in a further embodiment, from about 1000°C to about 1800°C, in a further embodiment, from about 1050°C to about 1800°C, in a further embodiment, from about 1100°C to about 1800°C, in a further embodiment, from about 1150°C to about 1800°C, in a further embodiment, In a further embodiment, the temperature is about 1200°C to about 1800°C, in a further embodiment, about 1250°C to about 1800°C, in a further embodiment, about 1300°C to about 1800°C, in a further embodiment, about 1350°C to about 1800°C, in a further embodiment, about 1400°C to about 1800°C, in a further embodiment, about 1450°C to about 1800°C, in a further embodiment, about 1500°C to about 1800°C, in a further embodiment, about 1550°C to about 1800°C, in a further embodiment, about 1600°C to about 1800°C, in a further embodiment, about The reaction may be carried out at a temperature range of about 1650°C to about 1800°C, in further embodiments about 1700°C to about 1800°C, in further embodiments about 1750°C to about 1800°C, about 800°C, about 850°C, about 900°C, about 950°C, about 1000°C, about 1050°C, about 1100°C, about 1150°C, about 1200°C, about 1250°C, about 1300°C, about 1350°C, about 1400°C, about 1450°C, about 1500°C, about 1550°C, about 1600°C, about 1650°C, about 1700°C, about 1750°C, or about 1800°C.

[0056] In an embodiment of the present disclosure, the chlorination step may take from about 10 minutes to about 8 hours, in a further embodiment, from about 20 minutes to about 8 hours, in a further embodiment, from about 30 minutes to about 8 hours, in a further embodiment, from about 40 minutes to about 8 hours, in a further embodiment, from about 50 minutes to about 8 hours, in a further embodiment, from about 1 hour to about 8 hours, in a further embodiment, from about 1.5 hours to about 8 hours, in a further embodiment, from about 2 hours to about 8 hours, in a further embodiment, from about 2.5 hours to about 8 hours, in a further embodiment, from about 3 hours to about 8 hours, and in a further embodiment, about 3.5 hours. in a further embodiment, from about 4 hours to about 8 hours, in a further embodiment, from about 4.5 hours to about 8 hours, in a further embodiment, from about 5 hours to about 8 hours, in a further embodiment, from about 5.5 hours to about 8 hours, in a further embodiment, from about 6 hours to about 8 hours, in a further embodiment, from about 6.5 hours to about 8 hours, in a further embodiment, from about 7 hours to about 8 hours, in a further embodiment, from about 7.5 hours to about 8 hours, in a further embodiment, from about 10 minutes to about 7.5 hours, in a further embodiment, from about 10 minutes to about 7 hours, in a further embodiment, 10 minutes to about 6.5 hours, in a further embodiment, from about 10 minutes to about 6 hours, in a further embodiment, from about 10 minutes to about 5.5 hours, in a further embodiment, from about 10 minutes to about 5 hours, in a further embodiment, from about 10 minutes to about 4.5 hours, in a further embodiment, from about 10 minutes to about 4 hours, in a further embodiment, from about 10 minutes to about 3.5 hours, in a further embodiment, from about 10 minutes to about 3 hours, in a further embodiment, from about 10 minutes to about 2.5 hours, in a further embodiment, from about 10 minutes to about 2 hours, in a further embodiment, from about 10 minutes to about 1.5 hours, in a further embodiment In further embodiments, the reaction may be carried out over a period ranging from about 10 minutes to about 1 hour, in further embodiments from about 10 minutes to about 50 minutes, in further embodiments from about 10 minutes to about 40 minutes, in further embodiments from about 10 minutes to about 30 minutes, and in further embodiments, from about 10 minutes to about 20 minutes, about 10 minutes, about 20 minutes, about 30 minutes, about 40 minutes, about 50 minutes, about 1 hour, about 1.5 hours, about 2 hours, about 2.5 hours, about 3 hours, about 3.5 hours, about 4 hours, about 4.5 hours, about 5 hours, about 5.5 hours, about 6 hours, about 6.5 hours, about 7 hours, about 7.5 hours, or about 8 hours.

[0057] In one aspect of the present disclosure, the reaction conditions for the alkaline leaching step and / or the chlorination step may be advantageously adjusted based on the composition of impurities in the graphite feed material. In an embodiment of the present disclosure, a graphite feed material containing a higher proportion of silicates, i.e., metal oxides, may be subjected to leaching conditions using a higher concentration of NaOH or KOH, and optionally a longer leaching time. In an embodiment of the present disclosure, a graphite feed material containing a lower proportion of silicates, i.e., metal oxides, may be subjected to leaching conditions using a lower concentration of NaOH or KOH, and optionally a shorter leaching time. In yet a further embodiment of the present disclosure, the composition of impurities in the graphite feed material may be such (e.g., a sufficiently low content of silicates) such that the alkaline leaching step may be omitted and the graphite feed material may be subjected to the chlorination step without any prior alkaline leaching. Those skilled in the art will appreciate that all process conditions, with reference to the alkaline leaching step and / or the chlorination step, such as, for example, the treatment time, treatment temperature, and / or concentration of alkaline material, can be varied to optimize the yield of the desired product, and it is within the skill of the skilled artisan to do so.

[0058] In one aspect of the present disclosure, it may be possible to achieve the required purity of the particulate graphite material using only a chlorination step, as illustrated in Figures 1 and 2. In such an embodiment, the alkali leaching step may be omitted. The chlorine-containing gas laden with chlorinated impurities may then be treated to remove the impurities. In one embodiment, the chlorine-containing gas laden with chlorinated impurities is quenched in water, and the chlorinated impurities (e.g., metal chlorides) are separated from the Cl2 gas by filtration and / or evaporation of the quenching aqueous solution. Quenching may be performed using a contacting device such as a wet scrubber. The chlorinated impurity-free Cl2 gas may then be combusted using hydrogen gas (H2) to form an aqueous hydrochloric acid solution, which may be sold. In one embodiment, as practiced by the titanium dioxide pigment industry, the chlorine-containing gas laden with chlorinated impurities may be reacted with oxygen (O2) to convert the chlorinated impurities (e.g., metal chlorides) to solid metal oxides, which may then be collected using standard collection devices such as electrostatic precipitators or bag filters.

[0059] In one aspect of the present disclosure, chlorine gas (Cl2) can be advantageously recycled back to the process for further processing of the graphite feed material. In one embodiment of the present disclosure, the chlorine gas free of metal impurities can be purified before being recycled back to the process (FIG. 2). In an embodiment of the present disclosure, purification includes removing any H2 and / or HCl that may be present in the chlorine gas after removal of chlorinated impurities. It is noted that any hydrogen present in the system is prone to react with chlorine gas, resulting in the formation of HCl. The reaction between hydrogen and chlorine occurs readily at temperatures above 250° C. and is accelerated by the presence of moisture. In one embodiment of the present disclosure, any such HCl can be removed from the chlorine gas by condensation. Sulfuric acid (H2SO4) is then used to dry the chlorine gas, resulting in the removal of any residual H2. The resulting purified chlorine gas is then compressed and recycled back to the process for further processing of the graphite feed material.

[0060] One of the technical challenges associated with high temperature chlorination processes is obtaining and maintaining an optimal temperature range where metal oxide impurities are effectively chlorinated while avoiding any excessive oxidation of the graphite feed material. In one aspect, the present disclosure relates to the chlorination of metal oxide impurities present in a graphite feed material using chlorine gas while avoiding any excessive oxidation of the graphite feed material.

[0061] In one embodiment of the present disclosure, the optimum temperature range can be obtained using indirect heating with either fuel (e.g., natural gas or fuel oil) or electricity. In a further embodiment of the present disclosure, the optimum temperature and control of the atmosphere can be obtained using a plasma torch. In this case, chlorine would provide both the gas for plasma ionization and purification via chlorination. In one aspect of the present disclosure, a plasma torch may be used in conjunction with a rotary kiln.

[0062] In a further embodiment of the present disclosure, the optimum temperature range can be obtained by adding a controlled level of oxygen to the chlorine gas, resulting in the generation of sufficient heat energy to maintain the temperature range required to provide oxidation of the small amount of graphite feed material and efficient chlorination of metal oxide impurities. In one embodiment of the present disclosure, a Cl2 / O2 gas mixture containing 95 wt% Cl2 and 5 wt% O2 can be used for a process temperature of about 1100°C. Those skilled in the art will appreciate that the balance of the Cl2 / O2 gas mixture is temperature dependent and can be varied to optimize the yield of the desired product, and doing so is within the skill of the artisan. Higher process temperatures typically mean higher O2 content. In one embodiment, the chlorination step can be carried out at a temperature range of about 800°C to about 1800°C.

[0063] In one aspect of the present disclosure, the particulate graphite feed material is natural flake graphite. In one embodiment of the present disclosure, the natural flake graphite feed material is a flotation concentrate having a particle size of about 45 micrometers to about 800 micrometers. In a further embodiment of the present disclosure, the natural flake graphite feed material is a flotation concentrate that has been reduced in size ("micronized") to about 5 micrometers to about 30 micrometers, or about 10 micrometers to about 30 micrometers. In yet a further embodiment of the present disclosure, the natural flake graphite feed material is a flotation concentrate that has been reduced in size ("micronized") to about 5 micrometers to about 30 micrometers, or about 10 micrometers to about 30 micrometers, and that has been shape-modified (spheroidized).

[0064] Processing very fine particulates (e.g., ≦200 micrometers) on a commercial scale through standard pyrometallurgical reactors such as shaft furnaces, rotary kilns, Acheson furnaces, or fluidized bed reactors can be difficult, specifically resulting in significant entrainment and loss of material to the gas phase. In one aspect, the present disclosure relates to agglomeration of particulate graphite feed material to produce an agglomerated particulate graphite feed (e.g., by using mechanical briquetting or by using an agglomerating agent). In addition to the benefits of simplified material handling and storage, agglomeration of particulate graphite feed provides an efficient continuous process while minimizing losses to the gas phase (e.g., entrainment by chlorine gas during the chlorination step). Agglomeration of particulate graphite feed material can be performed using standard industrial techniques, including, but not limited to, mechanical briquettes, disc and drum pelletizers, pin mixers, and high intensity mixer / agglomerators. In one embodiment of the present disclosure, agglomeration includes the use of an agglomerating agent. In a further embodiment of the present disclosure, the agglomerating agent includes a binder, more specifically, a carbonaceous binder. In yet further embodiments of the present disclosure, the carbonaceous binder is at least one of lignin, starch, modified starch, amylopectin, modified amylopectin, amylose, modified amylose, chitosan, chitin, guar gum, modified guar gum, cellulose, modified cellulose (carboxyalkylated cellulose and carboxymethyl cellulose), and polyvinyl acetate (PVA). In yet further embodiments of the present disclosure, the carbonaceous binder comprises an organic resin binder material. In yet further embodiments of the present disclosure, the organic resin binder material is at least one of petroleum or coal tar pitch. The carbonaceous binder may contain impurities and thus contribute to the overall non-purity load removed by the refining process. In one embodiment of the present disclosure, the refining process and various operating conditions can be adjusted while considering the binder composition. In a further embodiment of the present disclosure, the aggregates are heat treated at elevated temperatures (e.g., 400-1200°C) under an inert atmosphere to remove organic volatiles and carbonize the binder.

[0065] Carbon coating is essential when producing high purity particulate graphite particles for use in LiBs. To that end, the use of a carbonaceous binder advantageously provides the added benefit of reducing the specific surface area of ​​the particulate graphite feed material as measured by the Brunauer-Emmett-Teller (BET) adsorption method, which is beneficial for LiB performance. This specific surface area (BET) is an important property of purified particulate graphite materials. The BET surface area of ​​NFG is generally too large for LiB use and must be reduced, and thus, this is the basis why NFG used in LiBs is usually coated with an amorphous carbon layer. In one aspect of the present disclosure, the use of a carbonaceous binder to mitigate material loss to the gas phase also provides the unexpected benefit of coating the purified particulate graphite material. Agglomeration of the particulate graphite feed material can be performed by methods known in the art, such as those described in US 8,491,677, which is incorporated herein by reference.

[0066] In one aspect of the present disclosure, the particulate graphite feed material can be agglomerated using mechanical briquetting with or without the use of aggregating agents. Compared to agglomeration using low-intensity pelletizing equipment such as drum or disk pelletizers, mechanical briquetting offers greater flexibility to control the physical properties of the agglomerates, such as the agglomerate size distribution and the density of the individual agglomerates. This allows the agglomeration process to be tuned to obtain the agglomerate properties required to optimize the purification process. To that end, the gas permeability of the individual agglomerates can be advantageously controlled by controlling the briquetting pressure, and the gas permeability of the agglomerate bed can be advantageously controlled by controlling the agglomerate size distribution. In combination, these contribute to controlling the bulk flow of chlorine gas through the agglomerate bed and the diffusion of chlorine gas through the individual agglomerates during the chlorination process. Furthermore, the electrical properties of the individual agglomerates, such as electrical resistivity, can be advantageously controlled by controlling the briquetting pressure, and the electrical properties of the agglomerate bed, such as electrical resistivity, can be advantageously controlled by controlling the agglomerate size distribution. In combination, these help to control heat generation during chlorination when the chlorination reactor is heated by passing an electric current through the bed, as is practiced in the Acheson furnace.

[0067] In one aspect of the disclosure, the particulate graphite feed material can be agglomerated using mechanical briquetting without the use of a flocculant. There may be certain circumstances where agglomeration without the addition of a flocculant or binder has significant potential advantages. So there is the simple cost savings from not purchasing the binder. There is the additional cost savings from removing the organic volatiles from the binder prior to chlorination, eliminating the need for a separate agglomerate heat treatment step. Furthermore, it eliminates the need to add water during agglomeration, thus saving on associated costs, since it eliminates the need to dry the agglomerates prior to chlorination. Still further, it prevents the addition of impurities from the binder, thus reducing the burden on the purification process. Still further, it prevents any potential adverse effects on the electrochemical performance of the product graphite due to unsuitable amorphous carbon resulting from the binder. In some embodiments where an uncoated purified particulate graphite material is produced, the material will be subjected to a separate carbon coating step before it is used in a LiB. Those skilled in the art will appreciate that the flexibility provided by having the ability to agglomerate with or without a binder will allow graphite purification process operators to optimize the process for their particular circumstances, taking into account the characteristics of the particular non-pure graphite feed, the desired refined product, and particular economic considerations.

[0068] Tap density (g / cm 3 ) is an important property of purified particulate graphite material. The tap density determines how much usable graphite can be packed into a battery. Higher tap density provides better battery performance, and is the reason why "flake" graphite is mechanically treated (spheroidized) to change the aspect ratio of the particles to more spherical for better packing. The process for purifying and producing high purity particulate graphite material of the present disclosure is amenable to processing any type of graphite feed material, regardless of morphology. In one embodiment, the graphite feed material may be spheroidized.

[0069] In one aspect of the disclosure, the process for purifying and producing high purity particulate graphite material from graphite feed material includes in-situ recovery and recycle of leaching agent and / or chlorine gas. These recovery and recycle steps optimize reagent usage while minimizing waste generation. In one embodiment of the disclosure, the process for purifying and producing high purity particulate graphite material from graphite feed material includes the use of an industry standard chloralkali system to generate NaOH or KOH solution required for the leaching step, and Cl2 gas required for the chlorination step. In an embodiment of the disclosure, a system for implementing the process for purifying and producing high purity particulate graphite material can include one or more chloralkali systems. In an embodiment where there is more than one chloralkali system, both NaOH and KOH, respectively, can be produced. In a further embodiment of the disclosure, the process can provide recycled NaCl or KCl from the neutralizer operation to replace that lost in the solid waste while bringing fresh NaCl or KCl to the process.

[0070] In one aspect of the present disclosure, a process for purifying and producing high purity particulate graphite material from graphite feed material includes the use of an industry standard chloralkali system to produce the alkaline solution required for the leaching step, and Cl2 gas required for the chlorination step. In an embodiment of the present disclosure, the process plant can be advantageously equipped with buffer storage for the alkaline solution and Cl2 gas produced by the chloralkali plant, effectively decoupling the reagent production from the purification process. This allows the plant to manage the chloralkali operation based on spot electricity rates (e.g., shutting off production during peak electricity demand periods), thus maximizing the plant's financial revenue. This is particularly attractive for regions with unstable electricity markets, such as those with a high percentage of renewable energy sources. EXAMPLES

[0071] The following examples are included to demonstrate preferred embodiments of the present disclosure. Those skilled in the art should understand that the techniques disclosed in the following examples represent techniques discovered by the inventors to work well in the practice of the present invention, and therefore can be considered to constitute preferred modes for its practice. However, those skilled in the art should understand in light of the present disclosure that many changes can be made in the specific embodiments disclosed and still obtain the same or similar results without departing from the spirit and scope of the present invention.

[0072] Example 1 In accordance with one embodiment of the present disclosure, a sample of natural flake graphite flotation concentrate with particle size less than 150 micrometers and a total purity of 96.22% by weight carbon as measured by the loss on ignition (LOI) method was reacted with flowing chlorine gas under fixed bed conditions for 120 minutes at 1400° C. After testing, the LOI purity of the graphite was determined to be 99.98% by weight carbon (LOI).

[0073] Example 2 A natural flake graphite flotation concentrate with a particle size of less than 150 micrometers and a total purity, as measured by the loss on ignition (LOI) method, of 96.22 wt.% carbon was leached at 140°C with 50 wt.% sodium hydroxide solution at 10% pulp density for 8 hours. After leaching, the LOI purity of the graphite was measured to be 99.23 wt.% carbon. The partially purified graphite was then agglomerated using a starch paste binder at an addition rate of 15 wt.% to form micropellets with a nominal diameter of 1 mm. The micropellets were then heated to 1000°C at 5°C / min in a tube furnace under flowing argon to remove volatile compounds and carbonize the binder. A sample of the carbonized micropellets was then reacted with flowing chlorine gas at 1200°C for 30 minutes under fluidized bed conditions. After testing, the LOI purity of the graphite was measured to be 99.99 wt.% carbon.

[0074] Example 3 A sample of the purified graphite from Example 2 was ground to a nominal particle size of 20 micrometers. The tap density of the resulting graphite was 0.91 g / cm. 3 The BET specific surface area is 3.21 m 2 / g, which are acceptable values ​​for commercially available LiB-grade graphite. The electrochemical performance of the graphite was then measured as follows: Anode slurries were prepared using polyvinylidene difluoride binder and N-methyl-2-pyrrolidone solvent. The anode slurries were cast onto copper foil and pressed using a calendar roll. 2032 format coin cells were constructed using cast anodes, lithium metal cathodes, and an electrolyte of 1.2 M lithium hexafluorophosphate consisting of ethylene carbonate:ethyl methyl carbonate:dimethyl carbonate (25:5:70% by volume). These cells were tested by the following cycles: Constant current charge C / 20 to 0.005 V. Hold constant voltage at 0.005 V until current drops to C / 50. Constant current discharge C / 20 to 1.5 V. Repeat once. Then constant current cycle at C / 10 from 0.005 to 1.5 V. The charge capacity was measured to be 417 mAh / g and the reversible charge capacity was measured to be 350 mAh / g, which are acceptable values ​​for commercial LiB-grade graphite.

[0075] Example 4 A sample of spheroidized natural flake graphite having a particle size of less than 45 micrometers and a total purity of 97.36 wt% carbon as measured by loss on ignition (LOI) method was leached with 50 wt% sodium hydroxide solution at 140°C and 10% pulp density for 8 hours. After leaching, the LOI purity of the graphite was measured to be 99.33 wt%. The partially leached graphite was briquette into 8 mm diameter spheroids without agglomerants. The average strength of the spheroids was measured to be 700 grams force. For reference, the carbon black industry typically specifies that the agglomerates need to have a strength of greater than 150 grams force to withstand typical industrial handling / transportation / storage. The spheroids were reacted with flowing chlorine gas at 1400°C for 60 minutes under fixed bed conditions. After testing, the LOI purity of the graphite was measured to be 99.97 wt% carbon (LOI).

[0076] Although the present disclosure has been described with reference to particular examples, it is to be understood that the present disclosure is not limited to the disclosed examples, but on the contrary, the present disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0077] All publications, patents, and patent applications are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference in its entirety.

Claims

1. 1. A process for purifying graphite, said process comprising: treating a particulate graphite feed with an agglomerating agent to produce an agglomerated particulate graphite feed; reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising purified agglomerated particulate graphite material and a chlorine-containing gas enriched in chlorinated impurities; and separating said purified agglomerated particulate graphite material from said mixture.

2. 1. A process for purifying graphite, said process comprising: agglomerating the particulate graphite feed using mechanical means to produce an agglomerated particulate graphite feed; reacting the agglomerated particulate graphite feed in the presence of a chlorine-containing gas to produce a mixture comprising purified agglomerated particulate graphite material and a chlorine-containing gas enriched in chlorinated impurities; and separating said purified agglomerated particulate graphite material from said mixture.

3. 10. The process of claim 1, further comprising leaching the particulate graphite feed using an alkaline leach solution to produce a slurry and subjecting the slurry to a separation step, wherein the leaching is carried out prior to treatment with the flocculant.

4. The process described in claim 2, further comprising leaching the particulate graphite supply using an alkaline leaching solution to produce a slurry and subjecting the slurry to a separation step, wherein the leaching is carried out before agglomeration using mechanical means.

5. 5. The process of any one of claims 1 to 4, wherein the chlorine-containing gas, rich in chlorinated impurities, is quenched to remove said impurities.

6. The process of claim 3 , wherein the flocculating agent comprises a carbonaceous binder.

7. The process of claim 3 , wherein the flocculant comprises an organic resin material.

8. 5. The process of claim 4, wherein the mechanical means comprises mechanical briquetting.

9. 9. The process of any one of claims 3 to 8, wherein the leaching is carried out using an aqueous NaOH solution, the aqueous NaOH solution comprising from about 10% to about 50% NaOH by weight.

10. 10. The process of any one of claims 3 to 9, wherein the leaching is carried out at a temperature in the range of from about 50°C to about 150°C.

11. 11. The process of any one of claims 3 to 10, wherein the leaching is carried out for a period ranging from about 15 minutes to about 16 hours.

12. 7. The process of claim 6, wherein the carbonaceous binder is at least one of lignin, starch, modified starch, amylopectin, modified amylopectin, amylose, modified amylose, chitosan, chitin, guar gum, modified guar gum, cellulose, modified cellulose, and polyvinyl acetate (PVA).

13. 8. The process of claim 7, wherein the organic resin material is at least one of petroleum or coal tar pitch.

14. The process of any one of claims 1 to 13, wherein the reaction with the chlorine-containing gas is carried out at a temperature in the range of about 800°C to about 1800°C.

15. 15. The process of any one of claims 1 to 14, wherein the reaction with the chlorine-containing gas is carried out for a period ranging from about 10 minutes to about 8 hours.

16. 16. The process of any one of claims 1 to 15, wherein the particulate graphite feed is at least one of synthetic graphite, mined natural flake graphite (NFG), or graphite recovered from spent LiBs.

17. 17. The process of any one of claims 1 to 16, further comprising grinding the purified agglomerated particulate graphite material to a particle size in the range of about 5 to about 30 micrometers.

18. 8. The process of claim 6 or 7, wherein the purified agglomerated particulate graphite material comprises a carbonized coating.

19. 10. The process of claim 8, further comprising carbon coating the purified particulate graphite material.

20. 6. The process of claim 5, further comprising recycling the quenched chlorine-containing gas back into the process.

21. 10. The process of claim 9, further comprising recycling the NaOH values ​​back into the process.

22. 22. The process of claim 21, wherein the NaOH solution is neutralized to produce a NaCl solution.

23. 23. The process of any one of claims 20 to 22, wherein the recycling comprises the use of a chloralkali system.

24. A particulate graphite material comprising a carbonized coating and having a purity greater than 99.95 wt% C.

25. 25. The particulate graphite material of claim 24, wherein the carbonized coating is produced from a carbonaceous binder or an organic resin material.

26. the carbonaceous binder is at least one of lignin, starch, modified starch, amylopectin, modified amylopectin, amylose, modified amylose, chitosan, chitin, guar gum, modified guar gum, cellulose, modified cellulose, and polyvinyl acetate (PVA); 26. The particulate graphite material of claim 25, wherein the organic resin material is at least one of petroleum or coal tar pitch.

27. 27. The particulate graphite material of any one of claims 24 to 26, comprising a particle size in the range of about 5 to about 30 micrometers.

28. 28. The particulate graphite material of any one of claims 24 to 27, wherein the graphite material is sourced from at least one of synthetic graphite or mined natural flake graphite (NFG).

29. Graphite particles for a lithium ion battery (LiB), the graphite particles having a purity greater than 99.95 wt. % C, and a sintered binder material connecting to at least a portion of a surface of the graphite particles.

30. 30. The graphite particles of claim 29, wherein the binder material is at least one of a carbonaceous binder or an organic resin material.

31. the carbonaceous binder is at least one of lignin, starch, modified starch, amylopectin, modified amylopectin, amylose, modified amylose, chitosan, chitin, guar gum, modified guar gum, cellulose, modified cellulose, and polyvinyl acetate (PVA); 31. The graphite particles of claim 30, wherein the organic resin material is at least one of petroleum or coal tar pitch.

32. 32. The graphite particles of any one of claims 29 to 31, comprising a particle size in the range of about 5 to about 30 micrometers.

33. Graphite particles according to any one of claims 29 to 32, wherein the graphite is sourced from at least one of synthetic graphite or mined natural flake graphite (NFG).

34. An electrode or electrochemical storage device comprising graphite particles according to any one of claims 29 to 33.

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