KR100796369B1 - Recovery method of high purity cobalt, copper and recycled plastics from wasted lithium ion batteryes - Google Patents

Abstract

A method for recovering high-purity valuable metals and recycled plastics from waste lithium ion batteries is provided to recycle all of positive electrodes, negative electrodes, and separators and concentrate and to recover high-purity cobalt efficiently. A method for recovering high-purity valuable metals and recycled plastics from waste lithium ion batteries includes: a pre-treatment step of separating positive electrodes, separators, and negative electrodes from waste lithium ion batteries; and a recovery step of recovering valuable metals or recycled plastics from the separated positive electrodes, separators, and negative electrodes. The pre-treatment step(S100) includes the steps of: (S110) cutting steel cans of the wasted lithium ion batteries; and (S120) separating jelly rolls from the cut steel cans. In the recovery step, the step(S400) of recovering recycled plastics from the separators includes the steps of: grinding the separators; washing the ground separators; and extruding the washed separators into pellets to obtain recycled resins. In the recovery step, the step(S300) of recovering coppers from the negative electrodes includes: grinding the negative electrodes; mixing the ground negative electrodes with a CaO-based solvent containing SiO2, and then melting the mixture at 1000 °C or higher; keeping the molten material under partial oxygen pressure for 30 minutes to a hour, and then naturally cooling the resultant to separate coppers from impurities. In the step of cutting the steel can, both length-directional ends of the steel can are cut and opened. In the step of separating out the jelly roll, the jelly roll is pushed from one opening of the steel can and separated from the steel can.

Description

Recovery of valuable metals and recycled plastics from waste lithium ion batteries {RECOVERY METHOD OF HIGH PURITY COBALT, COPPER AND RECYCLED PLASTICS FROM WASTED LITHIUM ION BATTERYES}

1 is a flow chart schematically showing a recovery process of valuable metals and recycled plastics from waste lithium ion batteries according to the present invention.

The present invention relates to a method for recovering valuable metals (cobalt, copper, etc.) from waste lithium ion batteries, and more particularly, to recycling all of the positive electrode, the negative electrode, and the separator of the cylindrical waste lithium ion battery. The present invention relates to a method for recovering valuable metals and recycled plastics from waste lithium ion batteries capable of efficiently separating steel cans and jelly rolls, and recovering cobalt, copper, and plastic from the anode, cathode, and separator constituting the jelly rolls. .

In general, the waste lithium ion battery is widely used as an electrochemical power source for mobile phones, notebook computers, ultra-small images, and acoustic electronic devices. Lithium ion battery is composed of a large amount of chemicals such as copper (copper), cobalt (cobalt), lithium (lithium) and separators, organic electrolytes.

The recycling technology for waste lithium ion batteries results in two approaches: cobalt and copper recovery and environmental pollution prevention. The simplest and most economical treatment method for waste lithium-ion batteries was first developed by Zhang et al., Which first separated LiCoO ₂ coated anodes from the waste batteries, separated LiCoO ₂ from the aluminum substrate, and then eluted with hydrochloric acid. After the cobalt is separated using an organic solvent (PC-88A) and lithium is precipitated with carbonate.

Lee developed a technique to separate LiCoO ₂ by hydrothermal synthesis at 200 ° C using LiOH aqueous solution without any pretreatment process and to simultaneously regenerate it with a new cathode active material. The treatment has been developed to effectively separate LiCoO ₂ and to obtain substrates aluminum and copper simultaneously.

Summarizing the above-mentioned prior art, recycling of waste lithium ion batteries is to recover valuable metals having high added value included in lithium ion batteries, and generally, after crushing waste lithium ion batteries, iron components are removed by magnetic lines and specific gravity difference, Wet recovery technology that separates non-metallic components, copper, aluminum, etc. by using various methods such as air classification, concentrates cobalt first, and recovers cobalt by precipitation, electrolytic extraction, solvent extraction, etc. through acid leaching. To achieve. However, the wet recovery technique has a high loss rate of cobalt in powder in the crushing and separation process, which is a pretreatment process, and recovers high-purity cobalt in the wet concentration process, but it is difficult to process large quantities and has a problem of secondary environmental pollution due to waste acid. Recently, a dry treatment method by high temperature melting has been studied due to this problem, but there is an advantage that a large amount of treatment is possible and treatment problems such as waste acid do not occur. Since there is a limit in separating metals other than cobalt, there is a disadvantage in that the purity of the cobalt is low and a secondary refining process by wet treatment is required. In order to overcome such a problem, an efficient separation process is required rather than a pretreatment process of crushing and separating the entire waste lithium ion battery, but it is not yet developed.

The present invention has been proposed in order to solve the above problems, by applying a pretreatment technology (separation technology) suitable for dry melting process to develop an environmentally friendly recycling technology of waste lithium ion battery, but the process is simple It is possible to recycle anode, cathode, and separator materials by innovatively improving the existing methods that are economically problematic due to the large loss rate of metals. Especially, high-purity cobalt with the advantages of bulk treatment of dry melting process and process speed It is an object of the present invention to provide a method for recovering valuable metals and recycled plastics from spent lithium ion batteries, which can efficiently concentrate and recover the same.

To recover valuable metals (cobalt, copper) and plastics from spent lithium ion batteries to achieve the above object, graphite is formed on a cobalt-containing anode, a polypropylene separator, and a copper foil, each formed in a flexible sheet form. A pretreatment step of separating the positive electrode, the separator and the negative electrode from a waste lithium ion battery composed of a jelly roll made of a coated negative electrode and a sealed steel can containing the jelly roll therein; And recovering the valuable metal or the recycled plastic from the anode, separator and cathode separated through the pretreatment step.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart schematically showing a process of recovering valuable metals (cobalt, copper) and plastics from a spent lithium ion battery according to the present invention. As shown in the drawing, the present invention is as follows.

(S100) pretreatment. The waste lithium ion battery is composed of a cobalt-containing anode formed of a flexible sheet, a polypropylene separator and a cathode coated with graphite on a copper foil, and a rolled jelly roll, and a cylindrical sealed steel can in which the jelly roll is accommodated. The waste lithium ion battery of such a structure needs a process of complete discharge. This is to prevent fire and explosion that may occur during the separation process and melting process.The discharge method is a wet discharge method in which undischarged batteries are precipitated in salt water, or an appropriate circuit device composed of a resistor and a capacitor is used to discharge residual current. A dry discharge method for discharging may be applied. In the discharged waste lithium ion battery, the steel can and the jelly roll are separated through the following process.

(S110) steel can cutting. The steel can is a sealed structure after the jelly roll is inserted therein, and the steel can is cut to separate the jelly roll inserted therein so that both ends of the steel can are opened. The cutting of the steel can may be any method capable of separating the jelly roll from the steel can, and preferably, for example, cutting both sides of the steel can in the longitudinal direction to open both sides of the steel can in the longitudinal direction. Or a method for cutting the steel can in the longitudinal direction. The cutting of both sides of the steel can in the longitudinal direction may be performed in various ways. For example, a rotary cutter may cut along the circumference of the steel can or the cutter may cut both sides of the steel can while linearly reciprocating. Method and the like.

(S120) Jelly Roll Separation. When both sides of the steel can are cut in the longitudinal direction through the above step, the jelly roll in the steel can is pushed through the pusher at one of the two sides in the longitudinal direction of the steel can to separate the steel can from the steel can.

Through the above process, the waste lithium ion battery is separated into a steel can and a jelly roll, and the separated jelly roll is in a state in which a positive electrode, a separator, and a cathode are wound in a sheet form, and the recovery process is performed by separating the positive electrode, the separator, and the negative electrode. Will go through.

(S200) Cobalt recovery from the anode.

(S210) crushed. The separated anode is put into a grinder and crushed. The crushing process is to increase the separation efficiency of cobalt. In order to smoothly dissolve the anode into the molten metal in which the base metal is melted, the specific surface area must be increased, so the grinding grain size of the anode is preferably 40 to 80 mm. Grinding below 40mm is not preferable because of the increase of grinding cost and loss.

(S220) melt. The crushed anode composed of crushed lithium cobalt oxide and aluminum is mixed with coke and CaO solvents, charged into a heating furnace and melted at 1,300 ~ 1,550 ℃ (the melting time is specific because the composition varies depending on the battery). It does not limit to 1 hour-about 1 hour 30 minutes). Specifically, the induction furnace is faster than the general electric furnace, and the induction furnace is suitable, and since the anode material contains a large amount of oxide and organic material with low electrical conductivity, the metal cobalt is dissolved first to melt the base metal. It is possible to maximize the performance of induction furnace by manufacturing (base metal) and injecting crushed anode material. In order to recover pure cobalt on a metal from an anode material coated with a cobalt oxide and a carbon-based (conductive carbon black) material on an aluminum foil, reduction of oxide cobalt oxide and removal of aluminum and carbon are required. As a result of analysis, anode material is composed of about 14 ~ 16% aluminum, 34 ~ 36% carbon and 49 ~ 51% cobalt. The addition of is preferable.

When the positive electrode scrap of the spent battery is added to the molten cobalt, the cobalt oxide coated on the aluminum foil in the paste state is decomposed into a polymer binder and separated from the aluminum substrate together with the conductive carbon powder in powder form. As it is separated, the cobalt oxide begins to dissolve into the cobalt molten metal in a high-temperature reducing atmosphere. The cobalt oxide powder is very fine powder and has a very low specific gravity. In view of the fact that slag is reduced and the recovery rate of the metal cobalt is reduced, coke was used as a separate reducing agent in order to minimize the amount of the cobalt oxide to be slag and maximize the recovery rate of the metal cobalt. The coke is 93% or more of carbon content, the input amount is preferably 7 to 12% by weight based on the raw material of the lithium ion battery cathode material. If the coke amount is less than 7% by weight, it is insufficient for the reduction reaction of cobalt oxide mixed into slag. If the amount of coke is more than 12% by weight, refining of aluminum into the slag is prevented due to excessive reduction reaction. In view of the decrease in the safety of operation and the increased amount of carbon remaining in the recovered cobalt metal mat, the amount of coke input is limited to 7 to 12% by weight of the total amount of raw materials.

In order to reduce the melting temperature of cobalt with a melting temperature of 1,560 ℃ and to remove impurities such as aluminum and carbon, a flux is added together with coke. CaO-based slag containing SiO ₂ with high removal efficiency and sufficient viscosity at melting operation temperature is used. Preferably, it is preferred to use a solvent of 1.5 to 3.0 the basicity (CaO / SiO ₂₎ ratio of CaO and SiO _2. When the basicity is less than 1.5, the fluidity is lowered, so that slag is not smoothly formed, and when the basicity is higher than 3.0, the melting point is increased to increase the wear of the furnace wall.

The amount of the SiO ₂ and CaO combination solvent charged is the weight of the metal and the slag generated after melting in consideration of the impurities removal efficiency such as aluminum and carbon acting as impurities of the lithium ion battery anode material and the purity of the cobalt metal produced. It is determined by the slag ratio, which is a ratio with the weight. In the present invention, the slag ratio (slag weight / metal weight) is charged after quantification in accordance with the amount of the raw materials to be added to be 0.05 or more. If the slag ratio is less than 0.05, it is preferable that the slag ratio is at least 0.05 or more because aluminum is oxidized and the reaction into the slag is not smoothly performed.

As described above, the mixture of the cathode raw material, the coke and the solvent of the cylindrical waste lithium ion battery is added to a pre-melted cobalt molten metal to be melted by heating. At this time, when the reaction of the aluminum foil in the positive electrode material is started, the temperature of the molten metal is increased by the violent oxidation reaction, and thus a temperature setting is required. If the melting temperature is too high, there is a problem of deterioration of the removal of impurities such as aluminum and damage of the furnace wall, so that the melting is performed within a temperature range of 1,350 ° C or higher. It is desirable to maintain the reaction time for about an hour.

(S230) Impurity Separation. The molten raw material is maintained under a partial pressure of air for a predetermined time and then cooled in a natural state so that the slag layer and the cobalt metal mat layer containing impurities are separately formed. When oxygen load is used here, the cobalt concentration increases with increasing carbon removal efficiency, but when the oxygen partial pressure is excessive, reduced cobalt metal is regenerated, which leads to secondary dry type for high purity cobalt production. It is preferable to keep it under the partial pressure of air in consideration of the refining process.

(S240) Secondary Melting. Finally, the cobalt metal mat produced through the first dry smelting process is a mat form containing aluminum with only about 3 to 4% by weight of carbon and the first step in the second refining process to produce high purity cobalt metal mat. A high-purity metallic cobalt ingot of 99.5% or more can be produced by adding a processed mat and melting it under the same conditions of melting as in the smelting process under oxygen partial pressure without additives such as a solvent.

(S300) Copper recovery from the cathode.

(S310) crushed. The separated negative electrode is put into a grinder and pulverized. The crushing process is to increase the separation efficiency of copper. The cathode, like the anode, is ground to 40-80 mm.

(S320) Melt. The negative electrode is mixed with a CaO-based solvent containing SiO ₂ and charged into a heating furnace to be melted at a temperature of 1,000 ~ 1,300 ℃.

(S330) Impurity Separation. After maintaining for a certain time under the partial pressure of air and cooling in a natural state to form a separate slag layer and a copper metal mat layer containing impurities.

(S400) Recovery of plastic from separator.

(S410) crushed. Grinding is about 10mm to smoothly insert the separator.

(S420) wash. The pulverized separator is put into a washing tank and washed to remove foreign substances such as dust from the separator, and the washed separator is dehydrated and dried.

(S430) extrusion. The dried separator is masterbatched and pelletized using a single screw or twin screw extruder to obtain recycled plastics.

Hereinafter, the present invention will be described in more detail with reference to specific examples.

<Example>

Discharge cylindrical waste lithium ion batteries and batteries that are used in a variety of ways, such as notebooks by a wet or dry discharge method.

Next, the cathode raw material consisting of cobalt oxide, carbon, and aluminum is mixed with coke and CaO solvents, and then heated to a high temperature of 1,500 ° C. or higher at a heating rate of 25 ° C./min or higher, and charged into a molten metal cobalt-containing melt 1,350. Heat to maintain a temperature above &lt; RTI ID = 0.0 &gt;

Through the separation device for the present invention, the other material is completely separated and processed by mixing 80 kg of coke 6kg, SiO ₂ and CaO to a basic degree of 1.5 to 3.0 to 80kg of positive electrode raw material without impurities such as iron, nickel, copper, etc. 4 kg of the mixture was charged into a molten metal in an induction furnace in which 10 to 20 kg of base metal metal cobalt was dissolved, and after cooling for 1 to 2 hours with air input under optimum temperature control according to the reaction process of the material, the mixture was naturally cooled.

When the coke and the solvent are heated and melted at a high temperature in the mixed state, the cobalt oxide is melted to form a molten metal, and the aluminum and carbon components are absorbed in the solvent in the form of an oxide having a high melting point and thus have a low specific gravity. As a result, it floats on the upper portion of the molten metal. In particular, the coke serves to reduce the cobalt oxide having a tendency to float with a very low specific gravity in the form of fine powder, and not to be absorbed by the solvent, to the metal mat, in which the molten cobalt metal and the oxide phase are separated.

The cobalt metal mat recovered by the above method is charged to the induction furnace again, and heated to 1,550 ° C. at a heating rate of 30 ° C./min under oxygen partial pressure to remove carbon, thereby preparing a high purity cobalt metal mat.

When the metal mat and the slag are cooled, the chemical composition of each metal mat is analyzed, and the entire lithium ion battery and the waste lithium ion battery are pulverized to remove the Fe component without separating the positive electrode and the negative electrode, and then dry treatment is performed. Table 1 shows a comparison of components when only the positive electrode material is dried by using the efficient separator of the present invention.

TABLE 1

As shown in Table 1, the metal mat produced through dry smelting after removing only the steel component after the entire grinding is cobalt and copper components of 91.81% by weight and 6.85% by weight, respectively. It was found that the metal mat of the present invention, which was effectively smelted only by pretreatment of the positive electrode material, was separated into a high purity metal mat having a cobalt content of 99.5 wt% or more.

Therefore, by using the treatment conditions of the present invention as described above, it was possible to effectively recover and recover the expensive cobalt from the waste lithium ion battery, and in the case of the anode material, it was possible to recover the high-purity copper by the same method as the cathode material recovery method. .

Additionally, cobalt and copper are recovered from the separated anode and cathode materials using an efficient separator, and the remaining polypropylene separator is also cleaned to remove foreign substances such as carbon and small amount of cobalt oxide remaining through a simple washing process, and then extruded into a master. By batch-processing, recycled plastic pellets with high whiteness and high economic value can be recovered, and the total material recycling technology of waste lithium ion batteries can be realized.

As described above, according to the recovery method of valuable metals and recycled plastics from the waste lithium ion battery according to the present invention, the process is simpler than the conventional wet recovery method in the recycling technique using dry melting of the cylindrical waste lithium ion battery. It is possible to process in large quantities, and in particular, by separating the positive electrode, the negative electrode, and the separator using an efficient separation process, each material is recovered to crush the whole to recover valuable metals. As it can minimize the environmental pollution and the loss of recyclable resources, it is very economically effective.

    Although the present invention has been described above with reference to the above-mentioned preferred embodiments, it is possible to make various modifications or changes without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

Claims (8)

delete delete The anode and the separator from a waste lithium ion battery composed of a cobalt-containing anode each made of a flexible sheet, a polypropylene separator and a cathode coated with graphite on a copper foil, and a rolled jelly roll and a sealed steel can containing the jelly roll therein. And a pretreatment step of separating the cathode; And, Recovering the valuable metal or recycled plastic from the anode, separator and cathode separated by the pretreatment step, The pretreatment step includes cutting a steel can of the waste lithium ion battery, separating the jelly roll from the cut steel can, Recovering the recycled plastic from the separator during the recovery step includes the step of crushing the separator, washing the crushed separator, extruding the washed separator in the form of pellets to obtain a recycled resin, In the recovering step, recovering copper from the negative electrode may include: pulverizing the negative electrode, mixing the pulverized negative electrode with a CaO-based solvent containing SiO ₂ , and melting at a temperature of 1,000 ° C. or higher, and the melt is oxygen In the method of recovering valuable metals and recycled plastics from a waste lithium ion battery consisting of the steps of maintaining for 30 minutes to 1 hour under partial pressure and then naturally cooling to separate the metallic copper and impurities. In the steel can cutting step, both ends of the steel can are cut in the longitudinal direction, respectively, so that both ends of the steel can are opened, and in the jelly roll separation step, one side of the openings of the steel can in which both sides of the steel can are opened A method for recovering valuable metals and recycled plastics from spent lithium ion batteries, comprising: pushing the jelly roll to separate the steel can from the steel can. delete delete 4. The method of claim 3, wherein recovering cobalt from the positive electrode during the recovering step comprises: crushing the positive electrode, mixing the crushed positive electrode with a solvent to melt the melt, and then mixing the melted mixture under air pressure for 1 hour to 2 hours. Separating the cobalt-containing valuable metal and impurities by cooling for a time, and recovering the cobalt mat by secondary melting the valuable metal mat in a condition in which only an oxygen load is present. In the melting step, by melting and mixing the molten cobalt metal in the induction furnace, coke and CaO-based solvent containing SiO ₂ and the crushed anode, The coke is 93% or more of carbon content, 7 to 12% by weight relative to the total 100% by weight of the positive electrode, the solvent has a basicity (CaO / SiO ₂ ratio) within 1.5 to 3.0 and slag ratio (slag weight / A method for recovering valuable metals and recycled plastics from a spent lithium ion battery, wherein the metal weight) is formulated to be 0.05 or more. delete delete

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