CN107978815B - Pretreatment method of waste power battery - Google Patents

Abstract

The invention belongs to the technical field of resource recycling, and in particular relates to a pretreatment method for waste power batteries. The waste power battery is crushed, and then roasted in an oxygen-depleted furnace after crushing; the gas generated during the crushing and roasting process is successively processed by oxygen-rich high-temperature combustion, pure water spraying, pure water pool absorption, chemical pool absorption and denitration treatment, and then purified. The exhaust gas is discharged up to the standard; the calcined waste power battery is smashed for the second time, and finally the battery material, metal and organic carbide are separated by double sorting. The invention has simple process and is environment-friendly; it solves the problem of pollution caused by the volatilization of harmful elements in the organic matter and the electrolyte into the air, and at the same time increases the subsequent leaching efficiency, improves the production efficiency and reduces the production cost; the magnetic separation is combined with the cyclone classification. Combined and separate cyclone classification, the classification power consumption is reduced, the equipment is simple and reliable, has high economic value, and can realize the direct utilization of pretreatment materials.

Description

Pretreatment method of waste power battery

technical field

The invention belongs to the technical field of resource recycling, and in particular relates to a pretreatment method for waste power batteries.

Background technique

According to the assessment of the China Automotive Research Center, by 2020, China's scrapped power batteries will reach 200,000 tons. Scrap power batteries not only contain a large amount of metals, but also contain a certain amount of organic matter. The organic matter contains a certain proportion of elements such as S, F, P, Cl, etc., which exist in the form of solid and liquid, and the physical properties are also very different; water-based power batteries The organic matter can exist stably in the air, but it affects the effect of wet treatment. It needs to be separated in advance. Improper handling will also produce a large amount of toxic gas; while the organic matter of the organic power battery will support combustion and volatilize in the air. A large amount of toxic gas is produced, and it is difficult to avoid the release of toxic gas in conventional treatment, and it will also have a great impact on the production and operation environment.

In the recycling process of used power batteries, processes such as dismantling, crushing, leaching, iron removal, P204 extraction, P507 extraction, resin deep impurity removal, and electrowinning are generally used. It causes serious secondary pollution and is environmentally friendly for the recycling of waste power batteries. The traditional pretreatment method generally freezes the battery to recover the electrolyte, or directly conducts high-temperature calcination to decompose the electrolyte and organic matter.

The above two pretreatment methods are the current practice in the prior art. The former needs to consume a lot of refrigeration energy and equipment of special specifications. The latter will generate a lot of gas, and the consumption of recovered reagents will be large, which will result in high pretreatment costs. The amplitude increases, and at the same time, after the battery material is sintered and solidified, the subsequent leaching efficiency is reduced, which may affect the production organization.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the purpose of the present invention is to provide a pretreatment method for waste power batteries, which is simple in process and environmentally friendly, solves the problem of pollution caused by the volatilization of harmful elements in organic matter and electrolyte into the air, and increases the subsequent The leaching efficiency is improved, the production efficiency is improved, the production cost is reduced, the classification power consumption is low, and it has high economic value, and realizes the direct utilization of pretreatment materials.

The pretreatment method of the waste power battery according to the present invention comprises the following steps:

(1) crushing the waste power battery, and roasting it in an oxygen-depleted furnace after crushing;

(2) The gas generated in the process of crushing and roasting passes through oxygen-enriched high-temperature combustion, pure water spraying, pure water pool absorption, chemical pool absorption and denitration treatment in turn, and the purified exhaust gas is discharged up to the standard;

(3) The calcined waste power battery is pulverized for the second time, and finally the battery material, metal and organic carbide are separated by double sorting.

in:

Waste power batteries are nickel-hydrogen power batteries, capacitive power batteries or lithium-ion power batteries. Step (1) is preferably to first classify the waste power battery and then crush it, and classify the waste power battery, which is conducive to crushing.

In step (1), it is crushed to a particle size of 5-10 mm; in step (3), it is crushed for a second time to a particle size of 1-2 mm.

Crushing the waste power battery is as follows: sending the waste power battery into a crusher with negative pressure through an automatic conveyor for crushing, and the negative pressure is preferably -100Pa to -300Pa. When the waste power battery is broken, it will volatilize a certain amount of gas, and some of the battery's electricity will be released instantly during the crushing process, and it should emit sparks, or even ignite combustibles, resulting in an increase in the amount of gas. The components in the gas contain a certain amount of Toxic gas and inclusion of electrolyte and battery materials have certain toxicity. The inside of the crusher presents negative pressure, which can prevent the gas generated during the crushing process from leaking. The generated gas is introduced into the oxygen-rich high-temperature combustion zone through negative pressure for full combustion .

Roasting in an oxygen-depleted furnace is low-temperature roasting, the low-temperature roasting temperature is 300-450°C, and the roasting time is 20-30 minutes.

When the waste power battery is a nickel-metal hydride power battery or a capacitive power battery, the roasting temperature is 300°C, but the pole piece is relatively thick, and the roasting time is long, preferably 30min.

Roasting in an oxygen-lean furnace can minimize the amount of gas production, and make the organic matter exist in the form of carbides, avoiding excessive _CO2 content in the tail gas, and high _CO2 consumption in the subsequent chemical pools. A large amount of chemical reagents, Increase production costs. The generated gas undergoes oxygen-enriched high-temperature combustion before being sprayed with pure water. The main function is to convert the CO in the gas into CO ₂ , and the second is to fully convert the sulfide in the gas into SO ₃ . Conditions for oxygen-enriched high-temperature combustion. It is: the oxygen content is 40-55%, the temperature is 800-870°C, and the time is 30-60s. Then, it is sprayed with pure water, and the pure water tank absorbs sulfide and phosphide. The chemical tank absorbs the sulfide and phosphide that have not been completely absorbed in the previous two processes. The chemical reagents in the chemical tank are calcium hydroxide and sodium hydroxide, and sodium hydroxide. The mass fraction is 3-5% of calcium hydroxide. The tail gas also contains a certain amount of nitrogen oxides, which are sold out through the denitrification device, and the tail gas is discharged up to the standard.

The two-fold separation is magnetic separation and cyclone separation, specifically: obtaining non-magnetic materials and magnetic materials through magnetic separation, separating organic carbides and battery materials from non-magnetic materials through cyclone separation, and separating magnetic materials through cyclone separation. Sorting separates metals and battery materials. The specific gravity of the roasted materials varies greatly. If only cyclone classification is used, multiple stages are required for separation, and the components separated in the middle have a large mixing ratio. First, magnetic separation can directly separate magnetic materials and non-magnetic materials, and magnetic materials and non-magnetic materials are then subjected to cyclone separation, reducing the number of classifications, with good separation effect and high efficiency.

Power batteries usually use steel shells, and the separated metal is used as scrap metal, which can be directly sold as scrap iron. After calcination and separation, the battery material has high purity and chemical activity, and can be used as the raw material for the subsequent dissolution process, which can be directly used for subsequent leaching, and the dissolution time can be greatly shortened; the organic carbide is compressed and used as charcoal fuel.

Compared with the prior art, the present invention has the following advantages:

(1) The treatment method of the present invention has simple process and is environmentally friendly; it solves the problem that organic matter and harmful elements in the electrolyte are volatilized into the air to cause pollution, and simultaneously increases the subsequent leaching efficiency, improves production efficiency, and reduces production costs.

(2) The present invention combines magnetic separation and cyclone classification, and separates cyclone classification to reduce classification power consumption, the equipment is simple and reliable, has high economic value, and can realize direct utilization of pretreatment materials.

Description of drawings

FIG. 1 is a process flow diagram of the pretreatment method for used power batteries according to the present invention.

Detailed ways

The present invention will be further described below in conjunction with the embodiments.

Example 1:

The sorted waste nickel-metal hydride power batteries are sent to the crusher with negative pressure through the automatic conveyor. The negative pressure is -100Pa, and the batteries crushed into 5-10mm are sent to the oxygen-depleted furnace for low-temperature roasting, and the low-temperature roasting temperature is 300 ℃. , the roasting time is 30min. The gas generated in the process of crushing and roasting goes through oxygen-enriched high-temperature combustion, pure water spraying, pure water absorption, chemical tank absorption and denitrification treatment in sequence. The oxygen content is 40-55%, the temperature is 800 °C, and the time is 60 s. The waste batteries after low-temperature roasting enter the secondary pulverizer for pulverization, and pulverize to a particle size of 1-2 mm. The non-magnetic materials and magnetic materials are separated by magnetic force The materials, magnetic materials and non-magnetic materials are separated by cyclone separation respectively. The sorted and separated metals are directly sold as scrap iron, the battery material is used as the raw material for the subsequent dissolution process, and the organic carbide can be used as charcoal fuel after being compressed.

This method is suitable for the pretreatment of waste nickel-hydrogen power batteries. After this treatment, S, Cl, and N in organics are removed in advance, and the removal rate reaches 99.6%. It drops greatly, and it peels off with a little vibration. In addition, after pretreatment, the moisture content of the battery material is less than 0.2%. In the subsequent two-fold sorting process, the adhesion is small, and the separated metal parts only need to be washed once with pure water, and the washing liquid and the battery material will enter the dissolution together. tank, the dissolution efficiency is greatly improved, from the original 24h to 7h.

Example 2:

The sorted waste capacitive power batteries are sent to the crusher with negative pressure through the automatic conveyor. The negative pressure is -300Pa, and the batteries that are crushed into 5-10mm are divided into the oxygen-depleted furnace for low-temperature roasting. The low-temperature roasting temperature 400 ℃, calcination time 25min. The gas generated in the process of crushing and roasting goes through oxygen-enriched high-temperature combustion, pure water spraying, pure water absorption, chemical tank absorption and denitrification treatment in sequence. The oxygen content is 40-55%, the temperature is 850°C, and the time is 50s. The waste batteries after low-temperature roasting enter the secondary pulverizer for pulverization, and pulverize to a particle size of 1-2mm. The non-magnetic materials and magnetic materials are separated by magnetic force. The materials, magnetic materials and non-magnetic materials are separated by cyclone separation respectively. The sorted and separated metals are directly sold as scrap iron, the battery material is used as the raw material for the subsequent dissolution process, and the organic carbide can be used as charcoal fuel after being compressed.

This method is suitable for the pretreatment of waste capacitive power batteries. After this treatment, S, F, and N in organic matter are removed in advance, and the removal rate reaches 99.4%. It drops greatly, and it peels off with a little vibration. In addition, after pretreatment, the moisture content of the battery material is less than 0.15%. In the subsequent two-fold sorting process, the adhesion is small, and the separated metal parts only need to be washed once with pure water, and the washing liquid and the battery material are dissolved together. tank, the dissolution efficiency is greatly improved, from the original 24h to 8h.

Example 3:

The sorted waste lithium-ion power batteries are sent to the crusher with negative pressure through the automatic conveyor. The negative pressure is -200Pa, and the batteries that are crushed into 5-10mm are divided into oxygen-depleted furnaces for low-temperature roasting. The low-temperature roasting temperature 450 ℃, calcination time 20min. The gas generated in the process of crushing and roasting goes through oxygen-enriched high-temperature combustion, pure water spraying, pure water absorption, chemical tank absorption and denitrification treatment in sequence. The oxygen content is 40-55%, the temperature is 820°C, and the time is 35s. The waste batteries after low-temperature roasting enter the secondary pulverizer for pulverization, and pulverize to a particle size of 1-2mm. Magnetically separate non-magnetic materials and magnetic materials. The materials, magnetic materials and non-magnetic materials are separated by cyclone separation respectively. The sorted and separated metals are directly sold as scrap iron, the battery material is used as the raw material for the subsequent dissolution process, and the organic carbide can be used as charcoal fuel after being compressed.

The method is suitable for the pretreatment of waste lithium-ion power batteries. After this treatment, S, Cl, F, P, and N in the organic matter are removed in advance, and the removal rate reaches 99.4%. The adhesion of the fluid is greatly reduced, and it peels off with a little vibration. In addition, after pretreatment, the moisture content of the battery material is less than 0.1%. In the subsequent two-fold sorting process, the adhesion is small, and the separated metal parts only need to be washed once with pure water, and the washing liquid and the battery material will enter the dissolution together. tank, the dissolution efficiency is greatly improved, from the original 24h to 8h.

Claims (7)

1. a pretreatment method of waste power battery, is characterized in that: comprise the following steps: (1) crushing the waste power battery under negative pressure conditions, and roasting it in an oxygen-depleted furnace after crushing; (2) The gas generated in the process of crushing and roasting passes through oxygen-enriched high-temperature combustion, pure water spraying, pure water pool absorption, chemical pool absorption and denitration treatment in turn, and the purified exhaust gas is discharged up to the standard; (3) The calcined waste power battery is pulverized for the second time, and finally the battery material, metal and organic carbide are separated by double sorting; in: Roasting in an oxygen-depleted furnace is low-temperature roasting, the low-temperature roasting temperature is 300-450 °C, and the roasting time is 20-30 min; The conditions of oxygen-enriched high-temperature combustion are: the oxygen content is 40-55%, the temperature is 800-870°C, and the time is 30-60s; The two-fold separation is: magnetic separation to obtain non-magnetic material and magnetic material, cyclone separation to separate organic carbide and battery material from non-magnetic material, and cyclone separation to separate metal and battery material from magnetic material. 2 . The pretreatment method for used power batteries according to claim 1 , wherein the used power batteries are nickel-metal hydride power batteries, capacitive power batteries or lithium-ion power batteries. 3 . 3. The pretreatment method of waste power battery according to claim 1, characterized in that: in step (1), it is crushed to a particle size of 5-10 mm; in step (3), it is crushed for the second time to a particle size of 1-10 mm. 2mm. 4. The pretreatment method for waste power batteries according to claim 1, wherein: crushing the waste power batteries is as follows: sending the waste power batteries into a crusher with negative pressure through an automatic conveyor for crushing, and the negative pressure The pressure is -100Pa～-300Pa. 5. The pretreatment method of waste power battery according to claim 1, characterized in that: when the waste power battery is a nickel-hydrogen power battery or a capacitive power battery, the roasting temperature is 300°C, and the roasting time is 30min. 6 . The pretreatment method for used power batteries according to claim 1 , wherein the chemical reagents in the chemical pool are calcium hydroxide and sodium hydroxide, and the mass fraction of sodium hydroxide is 3-5% of calcium hydroxide. 7 . 7. The pretreatment method for waste power batteries according to claim 1, wherein the separated metal is directly sold as scrap iron, the battery material is used as the raw material for the subsequent dissolving process, and the organic carbide is compressed as charcoal fuel .

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