Patent Description:
Lithium batteries are chemical batteries that rely on lithium ions to shuttle between cathodes and anodes to achieve charging and discharging purposes, which have the advantages of high energy density, high working voltage, long cycle life and large charging and discharging rates, and are widely used in the fields of new energy vehicles, 3C consumer products and energy storage batteries, where 3C refers to the abbreviation of computer, communication and consumer electronic products. The main components of a lithium ion battery include a cathode, an anode, shell, electrolyte and diaphragm paper. In the present dry process for treating waste lithium batteries, a large amount of valuable metals still remain in the recycled diaphragm paper, which will cause serious environmental pollution and waste of resources if the valuable metals are not utilized.

At present, the most commonly used method for treating diaphragm paper is an incineration method, which has high energy consumption, long process and low metal recycling rate. Especially, when the diaphragm paper is treated by the incineration method, on one hand, the residual metallic aluminum that serves as a cathode collector is very easy to melt due to its low melting point, which will penetrate into the battery powder, causing difficulties in separating valuable metals, and being not conducive to industrial production. On the other hand, the diaphragm paper cannot be recycled through the incineration method, resulting in waste of resources.

<NPL>)) discloses recovering the used separator from spent LIBs, cleaning with deionized water and reutilizing the separator without any modification for new battery fabrication. The obtained results endorsed to reuse the separator in a half-cell configuration by employing LiMn<NUM>O<NUM> as a cathode and Li metal as an anode. Compared with the commercial separator from Celgard, the test cell displayed almost equal capacity of about <NUM> mAh g-<NUM> at <NUM> mA g-<NUM> using the recovered separator.

<CIT> discloses a method for recovering a separator, a copper foil and a battery positive pole from a waste lithium-ion power battery. The method comprises the following steps that (<NUM>) discharging of the waste lithium-ion power battery is performed at <NUM>-<NUM>, and the voltage of the waste lithium-ion power battery is reduced to <NUM>-<NUM>. 5V; (<NUM>) the battery after discharging is sheared and broken into a geometrically regular shape by using a shearing crusher; (<NUM>) the obtained regular battery fragments are immersed in water and stirred, and after stirring is performed, the regular battery fragments are sieved; (<NUM>) the obtained oversize product is placed in a gravity separator, the separator is separated from the copper foil and the battery positive pole, and the separator is recovered; and (<NUM>) the obtained copper foil and battery positive pole are dried and then placed in an eddy current separator to separate and recover the copper foil and the battery positive pole. The method is easy in realization of industrialization, low in recovery cost and high in product recovery rate, and does not pollute the environment.

<CIT> discloses a comprehensive recovery method of waste rare earth batteries. The recovery method comprises the following steps that A, outer shells of the batteries are removed, and the batteries completely discharge; B, the waste rare-earth batteries are subjected to crushing treatment, and positive poles, negative poles, diaphragms, battery cores and steel shells are separated out; and C, the diaphragms are put into a sulfuric acid solution with the concentration of <NUM> mol/L to <NUM> mol/L according to the proportion that <NUM> of the diaphragms are put into <NUM> to <NUM> of the sulfuric acid solution, further a reaction is carried out for <NUM>-<NUM> hours, and then filtering is carried out to obtain the diaphragms and a filtrate. According to the comprehensive recovery method of the waste rare earth batteries, crude copper, crude nickel and other valuable substances are separated from positive and negative pole pieces through a physical method, furthermore, classification recovery of battery parts and battery materials is realized, separation and reutilization of rare earth and cobalt are realized, meanwhile, the using amount of chemical reaction reagents is reduced in the whole process, the reaction time is shortened, energy consumption is reduced, the technology is simple, the recovery rate is high, a foundation is established for the dynamic storage of rare resources such as the rare earth and the nickel, and furthermore, the method is low in cost and obvious in economic benefit.

<CIT> discloses a method for separating and recovering valuable components of waste power lithium batteries. The method is that the waste power lithium batteries are electrified and crushed, the organic solvent is volatilized and recovered, the lithium hexafluorophosphate is innocuously treated, and the light material, the heavy material and the intermediate weight material are sorted by a multi-component screening wind separator. Recovering diaphragm from light material, pyrolyzing intermediate weight material and powder, recovering pyrolysis oil and pyrolysis gas generated from pyrolysis as auxiliary fuel, separating aluminum foil and copper foil by color separation after pyrolysis residue is separated by intelligent kneading and washing machine, and separating shell, pile head and plastic from heavy material. The waste water and waste gas in the whole process of the method are treated centrally, no pollutants are discharged, and the whole component in the waste power lithium battery can be recovered efficiently. At the same time, the method fully realizes waste rebenefit, reduces energy consumption, reduces environmental pollution, and the process is simple and applicable to a wide range of batteries.

An object of the present invention is to provide a method for treating waste diaphragm paper of a lithium battery which is combined with physics and chemistry methods, and can satisfy the industrial production requirements of environmental friendliness, low energy consumption and high resource recycling.

In order to achieve the above object, the present invention adopts the following technical solutions.

The inventive method for treating waste diaphragm paper of a lihtium battery is defined in the appended claim <NUM>.

Preferably, in step (<NUM>), the crushed material after shearing and crushing has a size ranging from <NUM> to <NUM>.

Preferably, in step (<NUM>), the pneumatic separation is carried out at a speed of <NUM>/s to <NUM>/s.

According to the invention, in step (<NUM>), the method further includes a step of putting the copper-aluminum mixture into an eddy-current separator for separation to obtain metallic copper and metallic aluminum.

According to the invention, a rotor speed of the eddy-current separator ranges from <NUM> to <NUM>, a belt speed of the eddy-current separator ranges from <NUM> to <NUM>, and preferably a feeding speed is <NUM>% to <NUM>% of a unit time treatment capacity of the eddy-current separator.

Preferably, in step (<NUM>), a stirring speed of the flotation machine ranges from <NUM> r/min to <NUM> r/min, and a scraper speed of the flotation machine ranges from <NUM> r/min to <NUM> r/min.

Preferably, in step (<NUM>), the pulping the battery powder is to prepare the battery powder into a slurry with a mass concentration of <NUM>% to <NUM>%.

According to the invention, in step (<NUM>), the specific operation of the leaching of hydrometallurgy is: making the battery powder into a slurry, adding the slurry into a pickling solution for pickling, then adding a reducing agent for reductive leaching, and adjusting a pH to be acidic to obtain leachate.

According to the invention, the pickling solution is sulfuric acid; the reducing agent is preferably one of hydrogen peroxide or sodium sulphite; and the adjusting the pH to be acidic refers to adjusting the pH to a range of <NUM> to <NUM>.

According to the invention, in step (<NUM>), the pickling solution used in the pickling is sulfuric acid with a concentration of <NUM> mol/L to <NUM> mol/L.

According to the invention, in step (<NUM>), in the process of pickling the diaphragm paper, a mass ratio of the diaphragm paper to the pickling solution is <NUM>: (<NUM> to <NUM>).

According to the invention, in step (<NUM>), the pickling is carried out at a rotating speed ranging from <NUM> r/min to <NUM> r/min, and the pickling lasts for <NUM> minutes to <NUM> minutes.

Preferably, in step (<NUM>), a mesh number of a filter screen used in the filtering process ranges from <NUM> meshes to <NUM> meshes; and a centrifuge is used in the spin-drying process, and a rotating speed of the centrifuge ranges from <NUM>,<NUM> r/min to <NUM>,<NUM> r/min.

More preferably, both the pickling solution after the pickling and the pickling solution after spin-drying may be used for leaching of hydrometallurgy of the battery slurry.

Preferably, the diaphragm paper obtained in step (<NUM>) may be used for plastic granulation.

The treatment principle of the present invention is as follows:
According to the present invention, the diaphragm paper is treated by a method combining physics and chemistry, and the waste diaphragm paper is firstly sheared and crushed, and then subjected to pneumatic separation to obtain a light material and a heavy material; the light material diaphragm paper and the battery powder are subjected to flotation and separation to obtain the battery powder slurry and the diaphragm paper; the heavy material copper-aluminum mixture is subjected by eddy-current separation; the battery powder slurry after separation is transported to a wet section for treatment by a pump, the diaphragm paper after separation is pickled, and then the pickled diaphragm paper is filtered and spin-dried by a centrifuge, and then sold for plastic granulation; a physical method is used to separate metallic copper and metallic aluminum from the diaphragm paper and separate the diaphragm paper from the battery powder; and then, the valuable metals nickel, cobalt and manganese adhered in the diaphragm paper are separated by a chemical method, so that the valuable metals in the diaphragm paper are effectively recycled, three-wastes are not produced in the production process, and the industrial production requirements of environmental friendliness, low energy consumption and high resource recycling are satisfied.

The present invention has the advantages as follows:
According to the method, the diaphragm paper is treated by a method combining physics and chemistry, so that valuable metals in the waste diaphragm paper of the lithium battery are effectively recycled, and the recycled diaphragm paper can be used in the lithium battery again, which satisfies the industrial production requirements of environmental friendliness, low energy consumption and high resource recycling.

<FIG> is a process flowchart of Embodiment <NUM> of the present invention.

In order to deeply understand the present invention, the preferred experimental solutions of the present invention will be described below with reference to the embodiments to further illustrate the characteristics and advantages of the present invention. Any change or change that does not deviate from the main idea of the present invention can be understood by those skilled in the art, and the protection scope of the present invention is determined by the scope of the claims.

A method for treating waste diaphragm paper of a lithium battery included the following steps of:.

The diaphragm paper, the metallic copper, the metallic aluminum and the battery powder slurry were obtained after the above treatment steps, where the contents of various metals in the diaphragm paper were: <NUM>% copper, <NUM>% aluminum, <NUM>% nickel and <NUM>% cobalt; the contents of various metals in the metallic copper were: <NUM>% copper, <NUM>% aluminum, <NUM>% nickel and <NUM>% cobalt; the contents of various metals in the metallic aluminum were: <NUM>% copper, <NUM>% aluminum, <NUM>% nickel and <NUM>% cobalt; and the impurity contents of the battery powder slurry were detected to be: <NUM>% copper, <NUM>% aluminum, <NUM>% nickel and <NUM>% cobalt. The diaphragm paper, the metallic copper and the metallic aluminum may be sold directly, and valuable metals may be recovered from the battery powder slurry by leaching of hydrometallurgy. The separation rate of the metallic copper and the metallic aluminum is <NUM>%.

The results of various metal contents in the diaphragm paper, the metallic copper, the metallic aluminum and the battery powder slurry treated in Embodiment <NUM> are shown in Table <NUM>.

It can be seen from Tables <NUM> to <NUM> that the diaphragm paper treated by the method of the present invention contains very less of valuable metals, and may be used for plastic granulation. However, the diaphragm paper is treated by incineration at present, which wastes resources and pollutes the environment. According to the method of the present invention, the recycling rate of the metallic copper according to the method can reach over <NUM>%, and the recycling rate of the metallic aluminum can reach over <NUM>%, while the nickel, the cobalt and the manganese in the battery powder slurry can be recovered by leaching of hydrometallurgy, and can be used for the preparation of battery cathode materials again.

Claim 1:
A method for treating waste diaphragm paper of a lithium battery, comprising the following steps of:
(<NUM>) shearing and crushing waste diaphragm paper, and then carrying out pneumatic separation to obtain a light material and a copper-aluminum mixture;
(<NUM>) putting the light material into a flotation machine for separation to obtain diaphragm paper and battery powder; and
(<NUM>) pulping the battery powder, and then carrying out leaching of hydrometallurgy, pickling the diaphragm paper, and then filtering and spin-drying to obtain the diaphragm paper;
wherein, in step (<NUM>), the method further comprises a step of putting the copper-aluminum mixture into an eddy-current separator for separation to obtain metallic copper and metallic aluminum; a rotor speed of the eddy-current separator ranges from <NUM> to <NUM> and a belt speed of the eddy-current separator ranges from <NUM> to <NUM>;
in step (<NUM>), the specific operation of the leaching of hydrometallurgy is: after pulping the battery powder into a slurry, adding the slurry into a pickling solution for pickling, then adding a reducing agent for reductive leaching, and adjusting a pH to be acidic to obtain leachate;
in step (<NUM>), the pickling solution used in the pickling is sulfuric acid with a concentration of <NUM> mol/L to <NUM> mol/L; and in step (<NUM>), the pickling is carried out at a rotating speed ranging from <NUM> r/min to <NUM> r/min, and the pickling lasts for <NUM> minutes to <NUM> minutes; and
in step (<NUM>), in the process of pickling the diaphragm paper, a mass ratio of the diaphragm paper to the pickling solution is <NUM>: (<NUM> to <NUM>).