CN113540605B - A method for harmless treatment of pyrolysis exhaust gas of decommissioned old lithium batteries - Google Patents

Abstract

The invention discloses a harmless treatment method for pyrolysis tail gas of retired old lithium batteries, which relates to the field of comprehensive recycling of the old lithium batteries and specifically comprises the following steps: the electrode material of the retired lithium battery is crushed and then placed into a pyrolysis furnace for air pyrolysis, pyrolysis oil is recovered from oil gas discharged by pyrolysis through condensation, tail gas passes through alkali liquor to intercept fluoride in the tail gas, the cobalt/manganese-based catalyst is prepared by utilizing active powder of the retired lithium battery for vulcanization roasting and water leaching, and then the tail gas treated by the alkali liquor enters a fixed bed catalytic oxidation reactor filled with the cobalt/manganese-based catalyst recovered from the retired lithium battery for catalytic degradation treatment. The catalyst prepared by the retired lithium battery is used for treating the organic waste gas generated by the pyrolysis treatment of the catalyst, so that the catalyst is suitable for treating various retired lithium batteries such as lithium cobaltate, lithium manganate and nickel cobalt lithium manganate, and has strong applicability; the organic waste gas harmless treatment process has the advantages of low temperature, simple process, good operation environment, easy control and amplification and the like.

Description

A kind of harmless treatment method for pyrolysis exhaust gas of decommissioned old lithium battery

technical field

The invention relates to the field of comprehensive recycling and utilization of waste lithium ion batteries, in particular to a method for harmless treatment of pyrolysis tail gas of decommissioned old lithium batteries.

Background technique

Lithium-ion batteries have become an attractive energy storage technology due to their high efficiency, high power, and high energy density, and are undergoing expansion. However, the service life of lithium-ion batteries is only 2-3 years. If a large number of lithium-ion batteries are not properly disposed of after decommissioning, the toxic substances they contain will cause serious environmental hazards. At the same time, retired lithium batteries contain a lot of valuable strategic metal resources. Therefore, the recycling of decommissioned lithium batteries has the dual significance of environmental protection and resource conservation.

At present, there are various recycling methods for decommissioned lithium batteries. In order to reduce the impact of aluminum foil, copper foil, binders, etc. in electrode materials on the recycling efficiency and value of strategic metals, most recycling processes include electrode material pyrolysis treatment to remove electrode materials. The active material is pre-separated from the current collector. CN108666643A proposes a method and a device for recycling positive electrode materials of lithium ion batteries. The patent is to pulverize the positive electrode materials of lithium ion batteries to be recycled, and then to obtain material powders, the material powders are sorted by a sieving machine and a wind shaker to obtain sticky materials. For aluminum foil powder with lithium cobalt oxide impurities, the positive electrode active material obtained by this method has high content of aluminum foil and binder, which will cause problems such as long process flow and low value of recycled products. CN111841232 A proposes a method for purifying waste lithium battery multi-stage furnace pyrolysis tail gas. The method firstly passes the waste lithium battery pyrolysis exhaust gas through a cyclone, a flue gas cooler, a bag filter and a first/second/third stage. Washing tower treatment; then incinerate the exhaust gas, and then spray quicklime powder and activated carbon powder into the exhaust gas pipeline in sequence to remove fluoride, sulfide and dioxin in the exhaust gas, and finally pass the exhaust gas through a bag filter. After dust removal, pollution-free discharge is carried out. The treatment process of this method is complex and difficult to be practically applied. Moreover, the organic waste gas needs to be incinerated, and the treatment cost is high.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a harmless treatment method for the pyrolysis tail gas of decommissioned old lithium batteries.

The technical solution of the present invention is as follows:

A method for harmless treatment of pyrolysis tail gas of decommissioned old lithium batteries, wherein electrode materials in decommissioned lithium battery materials are pyrolyzed to obtain a mixture containing at least positive active powder and pyrolysis oil and gas, and the pyrolysis oil and gas are recovered by condensation and reflux. Pyrolysis oil, the condensed and refluxed tail gas is treated with lye to retain fluoride in the tail gas, and the positive active powder is used to prepare a cobalt/manganese-based catalyst, and then the lye-treated tail gas is processed by the cobalt/manganese-based catalyst Catalytic degradation treatment.

Preferably, the electrode material includes a retired positive electrode material or a mixture of a retired positive electrode material and a retired negative electrode material.

Preferably, the decommissioned anode material includes any one or a combination of at least two of lithium cobalt oxide, lithium nickel cobalt manganate, lithium manganate and lithium iron phosphate; the decommissioned anode material includes graphite anode, silicon anode and Any one or a combination of at least two of the silicon carbon negative electrodes.

Preferably, the binder contained in the electrode material includes any one or a combination of at least two of styrene-butadiene rubber, carboxymethyl cellulose, polyacrylic acid, and polyacrylonitrile.

Preferably, the exhaust temperature of the exhaust gas after the pyrolysis oil is recovered by condensation and reflux is lower than 100°C.

Preferably, the alkaline solution includes one or more of potassium hydroxide solution, sodium hydroxide solution and calcium hydroxide solution.

Preferably, the specific preparation method of the cobalt/manganese-based catalyst is as follows: mixing the positive electrode active powder and sulfide in a mass ratio of 0.25-4:1, calcining at 500-800 ° C after mixing, and the calcined product is solid-liquid at room temperature The ratio of 20-200g/L water immersion treatment, the leaching slurry is filtered and separated to obtain a solid, and the solid is a cobalt/manganese-based catalyst.

Preferably, the sulfide includes any one or a combination of at least two of sulfuric acid, sulfate, and pyrosulfate.

Preferably, the specific process of catalytic degradation treatment is as follows: the tail gas treated with alkali solution is passed into a fixed-bed catalytic oxidation reactor with a filling amount of 50-100 mg of cobalt/manganese-based catalyst at a flow rate of 50-100 ml/min.

The beneficial effects of the present invention are:

The invention provides a harmless treatment method for the pyrolysis tail gas of a retired old lithium battery, which utilizes the positive electrode active powder in the retired lithium battery to prepare a cobalt/manganese-based catalyst to treat the organic waste gas generated by the pyrolysis treatment thereof, and is suitable for the treatment of lithium cobalt oxide, A variety of retired lithium batteries such as lithium manganate and nickel cobalt manganate have strong applicability; the harmless treatment process of organic waste gas has the advantages of low temperature, simple process, good operating environment, easy control and amplification, etc. A method for treating waste lithium battery pyrolysis tail gas, and the removal rate of organic matter in the tail gas after treatment is very high.

Description of drawings

FIG. 1 is a flow chart of the method for harmless treatment of pyrolysis tail gas according to the present invention.

Detailed ways

The technical solutions of the present invention will be further described below with specific examples.

It should be noted:

Retired nickel-cobalt lithium manganate battery materials (positive electrode: nickel-cobalt lithium manganate, negative electrode: graphite, binder: styrene-butadiene rubber);

Decommissioned lithium manganate battery materials (positive electrode: lithium manganate, negative electrode: graphite, binder: carboxymethyl cellulose);

Retired lithium cobalt oxide battery materials (positive electrode: lithium cobalt oxide, negative electrode: silicon carbon, binder: polyacrylonitrile).

The following embodiments may refer to FIG. 1 .

Example 1

The decommissioned nickel cobalt lithium manganate battery material obtained by discharging and dismantling is subjected to air pyrolysis, and the positive electrode active powder in the pyrolysis material is mixed with potassium pyrosulfate according to a mixing mass ratio of 1:2, and then calcined at 700 ° C, and then calcined at 700 °C. The roasted product is leached with pure water at a solid-to-liquid ratio of 50 g/L at room temperature, and filtered to obtain a solid cobalt/manganese-based catalyst; the tail gas discharged from the pyrolysis is condensed to recover the pyrolysis oil, and then passed through the calcium hydroxide solution to retain the fluorine in the tail gas. 50ml/min of tail gas after lye treatment was passed into a fixed bed catalytic oxidation reactor filled with 60mg cobalt/manganese-based catalyst for catalytic degradation treatment at 200°C.

Example 2

The decommissioned lithium manganate battery material obtained by discharge and dismantling was subjected to air pyrolysis, and the positive electrode active powder in the pyrolysis material and sulfuric acid were mixed uniformly at a mixing mass ratio of 4:1, and then calcined at 750 °C, and then the calcined product was The solid-to-liquid ratio is 100g/L, and the pure water is leached at room temperature, and the solid manganese-based catalyst is obtained by filtration; the tail gas discharged from the pyrolysis is condensed to recover the pyrolysis oil, and then passed through the sodium hydroxide solution to retain the fluoride in the tail gas; alkali solution treatment The tail gas was passed into a fixed-bed catalytic oxidation reactor filled with 80 mg of cobalt/manganese-based catalyst at 70 ml/min for catalytic degradation treatment at 250 °C.

Example 3

The decommissioned lithium cobalt oxide battery material obtained by discharge and dismantling was subjected to air pyrolysis, and the positive electrode active powder and sodium pyrosulfate in the pyrolysis material were mixed at a mixing mass ratio of 1:3 and then calcined at 600 °C, and then the calcined product was The solid-liquid ratio is 50g/L and pure water is leached at room temperature, and then the solid cobalt-based catalyst is obtained by filtration; the tail gas discharged from pyrolysis is condensed to recover pyrolysis oil, and then passed through calcium hydroxide solution to retain the fluoride in the tail gas; alkaline solution treatment The latter exhaust gas was passed into a fixed bed catalytic oxidation reactor filled with 90 mg of cobalt-based catalyst at 80 ml/min to carry out catalytic degradation treatment at 150°C.

Example 4

Air pyrolysis was performed on the decommissioned nickel cobalt lithium manganate and lithium cobalt oxide battery mixed material obtained by discharging and dismantling, and the cathode active powder and potassium pyrosulfate in the pyrolysis material were mixed at a mixing mass ratio of 1:2 at 800 °C. Roasting, then the calcined product is treated by water immersion at room temperature with a solid-to-liquid ratio of 150g/L, and filtered to obtain a solid cobalt/manganese-based catalyst; the tail gas discharged from the pyrolysis is recovered by condensation. fluoride; the tail gas after alkaline solution was passed into a fixed-bed catalytic oxidation reactor filled with 100 mg of cobalt/manganese-based catalyst at 100 ml/min to carry out catalytic degradation treatment at 300 °C.

Example 5

Air pyrolysis was performed on the decommissioned nickel-cobalt lithium manganate battery and lithium manganate mixed material obtained by discharging and dismantling, and the positive electrode active powder and potassium pyrosulfate in the pyrolysis material were mixed at a mixing mass ratio of 1:2 at 500 °C. Roasting, then the calcined product is treated by water immersion at room temperature with a solid-to-liquid ratio of 20g/L, and filtered to obtain a solid cobalt/manganese-based catalyst; the tail gas discharged from the pyrolysis is recovered by condensation. fluoride; the tail gas after alkaline solution was passed into a fixed-bed catalytic oxidation reactor filled with 100 mg of cobalt/manganese-based catalyst at 100 ml/min, and catalytic degradation was carried out at 300 °C.

Example 6

Air pyrolysis was performed on the decommissioned lithium manganate and lithium cobalt oxide battery mixed material obtained by discharging and dismantling, and the positive electrode active powder and potassium pyrosulfate in the pyrolysis material were mixed at a mixing mass ratio of 1:4 and then calcined at 700 °C. The calcined product is then treated by water immersion at room temperature with a solid-to-liquid ratio of 200g/L, and filtered to obtain a solid cobalt/manganese-based catalyst; the tail gas discharged from the pyrolysis is condensed to recover the pyrolysis oil, and then passed through the calcium hydroxide solution to retain the fluorine in the tail gas. The tail gas after the alkali solution treatment was passed into a fixed bed catalytic oxidation reactor filled with 90 mg of cobalt/manganese-based catalyst at 90 ml/min, and the catalytic degradation treatment was carried out at 80 °C.

Comparative Example 1

The tail gas discharged from the pyrolysis of decommissioned lithium cobalt oxide battery materials is first processed through a cyclone separator, a flue gas cooler, a bag filter and a first/second/third stage scrubber; then the tail gas is incinerated, and then sent to the exhaust gas pipeline. The middle section is sprayed with quicklime powder and activated carbon powder in turn, and finally the exhaust gas is discharged after being dedusted by a bag filter.

GC-MS is used to detect and analyze the exhaust gas after the treatment in the above examples and comparative examples. To calculate the removal rate of organic matter, the calculation method is: (organic matter content before catalytic treatment - organic matter content after catalytic treatment)/organic matter content before treatment, and whether fluoride is detected, see the following table for details.

Table 1 Performance Test Values of Examples and Comparative Examples

sample Hydrocarbon organics removal rate (%) Fluoride (yes or no) Example 1 98.2 no Example 2 97.3 no Example 3 98.4 no Example 4 96.7 no Example 5 99.0 no Example 6 96.6 no Comparative Example 1 81.4 Have

It can be seen from the above table that the embodiment of the present invention has simpler process, milder conditions, better operating environment and easier control than the comparative example, and is a brand-new method for treating the pyrolysis tail gas of waste lithium batteries, and is suitable for treating lithium cobalt oxide, manganese A variety of retired lithium batteries such as lithium oxide and lithium nickel cobalt manganese oxide have strong applicability; and the removal rate of organic matter in the exhaust gas after treatment is very high, and no fluoride is discharged. However, the method in the comparative example has a complicated treatment process and is difficult to apply in practice, and the organic waste gas needs to be incinerated, so the treatment cost is high, and the comparative example uses lye spray, while in the embodiment of the present invention, the tail gas is directly passed into the lye, the reaction More complete, better fluoride removal.

The above-described embodiments are some, but not all, embodiments of the present invention. The detailed descriptions of the embodiments of the invention are not intended to limit the scope of the invention as claimed, but are merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Claims (9)

1. a decommissioned old lithium battery pyrolysis tail gas harmless treatment method is characterized in that, the electrode material in the decommissioned lithium battery material is pyrolyzed to obtain at least a mixture containing positive active powder and pyrolysis oil and gas, the thermal The pyrolysis oil is recovered by condensing and refluxing the hydrolyzed oil and gas, and the tail gas after condensation and reflux is treated with lye to retain the fluoride in the tail gas, and the cobalt/manganese-based catalyst is obtained by using the positive electrode active powder, and then the tail gas after the lye treatment is passed through the Cobalt/manganese-based catalyst for catalytic degradation treatment. 2 . The method for harmless treatment of pyrolysis tail gas of decommissioned old lithium batteries according to claim 1 , wherein the electrode material comprises a decommissioned positive electrode material or a mixture of a retired positive electrode material and a retired negative electrode material. 3 . 3. The method for harmless treatment of pyrolysis tail gas of decommissioned old lithium batteries according to claim 2, wherein the decommissioned positive electrode material comprises lithium cobalt oxide, lithium nickel cobalt manganate, lithium manganate and iron phosphate Any one or a combination of at least two of lithium; the decommissioned negative electrode material includes any one or a combination of at least two of a graphite negative electrode, a silicon negative electrode, and a silicon carbon negative electrode. 4. A method for harmless treatment of pyrolysis tail gas of decommissioned old lithium batteries according to claim 1, wherein the binder contained in the electrode material comprises styrene-butadiene rubber, carboxymethyl cellulose, polymer Any one or a combination of at least two of acrylic and polyacrylonitrile. 5 . The method for harmless treatment of pyrolysis tail gas of decommissioned old lithium batteries according to claim 1 , wherein the discharge temperature of the tail gas after the pyrolysis oil is recovered by condensation and reflux is lower than 100° C. 6 . 6. a kind of decommissioned old lithium battery pyrolysis tail gas harmless treatment method according to claim 1, is characterized in that, described alkaline solution comprises one of potassium hydroxide solution, sodium hydroxide solution and calcium hydroxide solution one or more. 7. a kind of decommissioned old lithium battery pyrolysis tail gas harmless treatment method according to claim 1, is characterized in that, the concrete preparation method of described cobalt/manganese-based catalyst is: The ratio is 0.25-4:1 mixing, after mixing, calcining at 500-800 ° C, the calcined product is subjected to water immersion treatment at a solid-liquid ratio of 20-200g/L at room temperature, and the leaching slurry is filtered and separated to obtain a solid, and the solid is cobalt/ Manganese based catalysts. 8 . The harmless treatment method for pyrolysis tail gas of decommissioned old lithium batteries according to claim 7 , wherein the sulfide comprises any one or at least two of sulfuric acid, sulfate and pyrosulfate. 9 . The combination. 9. a kind of decommissioned old lithium battery pyrolysis tail gas harmless treatment method according to claim 1, is characterized in that, the concrete process of catalytic degradation treatment is: tail gas after lye treatment is 50-100ml/min flow rate A fixed bed catalytic oxidation reactor filled with 50-100 mg of cobalt/manganese based catalyst was passed through.

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