Patent Description:
With the rapid development of modern science and technology, the problem of social energy and environmental ecological pollution has become increasingly prominent, especially the environmental and ecological pollution of various waste batteries has become the focus of social attention. Lithium ion batteries are widely used in the field of power batteries and energy storage batteries due to their high capacity, stable cycle performance, and high working platform voltage. However, in terms of the demand for battery materials, power and energy storage batteries generally are usually larger than conventional small batteries. Therefore, in the next <NUM> - <NUM> years, a large number of lithium ion batteries will be scrapped, and their recycling has high social value.

At present, in the recycling technology of waste lithium ion batteries at home and abroad, the main way to deal with the electrode active materials of waste lithium ion batteries is as follows: <NUM>) Acid reduction leaching to obtain a plasma leachate containing Li+, Ni<NUM>+, Co<NUM>+, Mn<NUM>+, Al<NUM>+, and Fe<NUM>+, depositing to remove iron and aluminum, and then adjusting the pH value to obtain a single metal deposition. <NUM>) Depositing to remove iron and aluminum, extracting nickel, cobalt, manganese, and then acid stripping to obtain a salt solution with only nickel, cobalt or manganese. There are still certain defects in the existing recycling technology of waste lithium ion batteries, such as "a method for recovering valuable metals in LiMn<NUM>-x-yNixCoyO<NUM> batteries and preparing LiMn<NUM>-x-yNixCoyO<NUM> batteries" published by Chinese patent <CIT>. This patent utilizes acid leaching to recover valuable metals from waste nickel cobalt lithium manganese batteries. Firstly, the electrode active material is leached with inorganic acid to obtain a leachate, which deposits iron and aluminum. Then alkali is added to control different pH values to obtain the deposit for a single metal. Finally, lithium is recovered. This method achieves the recovery of waste ternary lithium ion batteries, but there are problems with low product purity and secondary pollution caused by the production of non-degradable inorganic acid wastewater during acid leaching. Another example is "a process for recovering valuable metals from waste lithium batteries" published by Chinese patent <CIT>. In this patent, valuable metals such as cobalt, copper, nickel, and aluminum are recovered by a series of processes such as pre-treatment, leaching, chemical removal of impurities, and extraction. However, expensive extractants need to be used in the extraction process, and the operation is complex. Although this process is close to the recycling process used in industrial production, it still has the disadvantage of high recycling costs. The above processes all involve acid leaching followed by impurity removal to recover metals such as nickel, cobalt, and manganese, and finally to recover lithium. They only deal with a single type of waste lithium ion battery.

Chinese patent application <CIT> discloses a recycling process for lithium ion batteries which allows good recovery rates and can be used with different types of batteries. The method involves ball milling a colloidal solution of electrode powder starch and acid liquid. The method allows a single leaching step at room temperature and normal pressure. Chinese patent application <CIT> also relates to a method for recovering valuable methods from lithium batteries. In order to increase the purity of the recovered valuable metals in presence of Al, it is suggested to implement an alkali treatment of the electrode powders. However, there is still a need for new recycling methods for large scale implementation.

The present invention discloses a method for recovering valuable metals from waste lithium ion batteries. This method can reduce the concentration of impurity ions in the leachate, improve the purity and comprehensive recovery rate of valuable metals, and reduce the recovery cost.

The present invention is defined in the appended claim set.

The present invention provides a method for recovering valuable metals from waste lithium ion batteries. The method includes the following steps:.

Taking out the product obtained from calcination in the step <NUM> and using deionized water to extract the leachate and leaching residue with valence metal ions, and then obtaining the leachate after filtering.

In one embodiment given for illustrative purposes, the specific step <NUM> is as follows: the waste lithium ion batteries are short-circuit discharging the waste lithium ion batteries in a sodium sulfite solution until the termination voltage is below <NUM> V, wherein the solute concentration of the sodium sulfite solution is <NUM> - <NUM> %; disassembling the waste lithium ion batteries after short-circuit discharging to obtain battery cells; crushing the battery cells to obtain crushed materials; raising the temperature of the crushed materials to <NUM> - <NUM> at a rate of <NUM> - <NUM>/min in an air atmosphere, maintaining insulation and calcining to strip the adhesive; lime water with a concentration of not less than <NUM>/L is used to absorb the waste gas released during the adhesive stripping process to obtain calcium fluoride; separating the stripped product to obtain Al foil, Cu foil, and active electrode powders.

Furtherly in the invention, preferably, in the step <NUM>, the alkaline solution is one or more of NaOH, NH4OH and KOH, with a pH value of <NUM> - <NUM>, an alkaline cleaning time of <NUM> - <NUM>, and a temperature of <NUM> - <NUM>.

Preferably, in the step <NUM>, the pH value of the alkaline solution is <NUM> - <NUM>, the alkaline cleaning time is controlled within <NUM> - <NUM>, and the temperature is controlled between <NUM> - <NUM>.

Preferably, in the step <NUM>, the amount of starch is controlled at <NUM> - <NUM> wt. %, the solid-liquid ratio is controlled between <NUM> - <NUM>/L.

Preferably, in the step <NUM>, controlling the calcination temperature at <NUM> - <NUM>, calcination time at <NUM> - <NUM>, and the volume fraction of O<NUM> between <NUM> - <NUM> %.

Furtherly, in the deionized water leaching process of the step <NUM>, the solid-liquid ratio is controlled between <NUM> - <NUM>/L, the temperature is between <NUM> - <NUM>, and the leaching time is between <NUM> - <NUM>.

Preferably, in the deionized water leaching process of the step <NUM>, the solid-liquid ratio is controlled between <NUM> - <NUM>/L, the temperature is between <NUM> - <NUM>, and the leaching time is between <NUM> - <NUM>.

The advantages of the present invention are as follows:.

Accompanying drawings are for providing further understanding of embodiments of the disclosure. The drawings form a part of the disclosure and illustrate the principle of the embodiments of the disclosure along with the literal description. The drawings in the description below are merely some embodiments of the disclosure; a person skilled in the art can obtain other drawings according to these drawings without creative efforts. In the figures:
<FIG> is a process diagram of the method for recovering valuable metals from waste lithium ion batteries.

The present invention will be further described in conjunction with the accompanying drawings and specific examples.

As shown in <FIG>, the method for recovering valuable metals from waste lithium ion batteries of the present invention includes the following steps:.

Short-circuit discharging, dismantling, crushing, roasting, and screening on waste lithium ion batteries to obtain active electrode powders.

In an embodiment short-circuit discharging of waste lithium ion batteries, dismantling of discharged waste lithium ion batteries, crushing of the battery cells obtained after dismantling, stripping of adhesives, and separation to obtain active electrode powders. The above operations can all use well-known operations in this field. Preferably, the waste lithium ion batteries are short-circuit discharging the waste lithium ion batteries in a sodium sulfite solution until the termination voltage is below <NUM> V, wherein the solute concentration of the sodium sulfite solution is <NUM> - <NUM> %; disassembling the waste lithium ion batteries after short-circuit discharging to obtain battery cells; crushing the battery cells to obtain crushed materials; raising the temperature of the crushed materials to <NUM> - <NUM> at a rate of <NUM> - <NUM>/min in an air atmosphere, maintaining insulation and calcining to strip the adhesive; lime water with a concentration of not less than <NUM>/L is used to absorb the waste gas released during the adhesive stripping process to obtain calcium fluoride; separating the stripped product to obtain Al foil, Cu foil, and active electrode powders.

The waste lithium ion battery is one or more of the waste lithium nickel oxide lithium ion battery, lithium cobalt oxide lithium ion battery, lithium manganese oxide lithium ion battery, and lithium nickel cobalt manganese oxide lithium ion battery. The present invention can simultaneously process multiple types of waste lithium ion batteries without separate recycling, and is suitable for forming a closed circuit process without generating secondary pollution. This method combines environmental protection and economic benefits, with a wide range of variable operating conditions, simple operation, and good repeatability. Unlike most existing methods that are only applicable to laboratories, the present invention is particularly suitable for industrial large-scale production.

Using alkaline solution to wash the active electrode powders, then filtering to remove copper and aluminum.

The alkaline solution is one or more of NaOH, NH<NUM>OH and KOH, with a pH value of <NUM> - <NUM>, an alkaline cleaning time of <NUM> - <NUM>, and a temperature of <NUM> - <NUM>. Preferably, the pH value of the alkaline solution is <NUM> - <NUM>, the alkaline cleaning time is controlled within <NUM> - <NUM>, and the temperature is controlled between <NUM> - <NUM>.

The present invention pre cleans the active electrode powders with alkali, greatly reducing the concentration of impurity ions in the leachate. It can obtain a leachate with low impurity ion concentration and rich in valuable metal ions such as lithium, nickel, cobalt, and manganese. Further, it can solve the problem of low product purity in existing waste lithium ion battery recovery technology, avoid the loss of valuable metals during the traditional recovery process, and effectively improve the comprehensive recovery rate of valuable metals.

Drying the activated electrode powder after alkaline washing treatment, mix the dried activated electrode powder with starch and concentrated sulfuric acid in a predetermined proportion and stir evenly to obtain the mixed material.

In the mixing process, the dried active electrode powders are mixed with starch, and then concentrated sulfuric acid is added at a solid-liquid ratio of <NUM> - <NUM>/L and stirred evenly; wherein the amount of starch added is controlled at <NUM> - <NUM> wt. Preferably, the amount of starch is controlled at <NUM> - <NUM> wt. %, the solid-liquid ratio is controlled between <NUM> - <NUM>/L.

Putting the mixed material into a corundum crucible, and then moving the corundum crucible into a tube furnace to calcine with controlling the atmosphere.

In the process of high temperature reduction, controlling the calcination temperature at <NUM> - <NUM>, heating rate at <NUM>/min, and calcination time at <NUM> - <NUM>; wherein the atmosphere is a mixture of O2 and N2, and the volume fraction of O2 is controlled between <NUM> - <NUM> %. Preferably, controlling the calcination temperature at <NUM> - <NUM>, calcination time at <NUM> - <NUM>, and the volume fraction of O2 between <NUM> - <NUM> %.

In the deionized water leaching process, the solid-liquid ratio is controlled between <NUM> - <NUM>/L, the temperature is between <NUM> - <NUM>, and the leaching time is between <NUM> - <NUM>. Preferably, in the deionized water leaching process of the step <NUM>, the solid-liquid ratio is controlled between <NUM> - <NUM>/L, the temperature is between <NUM> - <NUM>, and the leaching time is between <NUM> - <NUM>.

The present invention adopts a comprehensive method of high temperature reduction and deposition for the recovery of valuable metals, solving the problems of low product quality, small processing scale, and complex process recovery by using a single deposition method. It avoids the use of expensive extractants for the separate recovery of valuable metals such as Cu, Ni, Co, and significantly reduces the recovery cost.

Soaking the waste lithium ion battery mixed with LiNiO<NUM>, LiCoO<NUM>, LiMnO<NUM>, LiNixCoyMn<NUM>-x-yO<NUM> in a <NUM> % sodium sulfite solution and discharging it to a termination voltage of <NUM> V; disassembling the discharged waste lithium ion battery to obtain battery cells; mechanical force is applied to the overall crushing of the battery cells to obtain crushed materials, and the particle size of the crushed materials is sieved out to be less than <NUM> for the following calcination; raising the temperature of the crushed materials in an air atmosphere at a rate of <NUM>/min to <NUM>, heat preservation and calcining for <NUM> hour, stripping the adhesive, and absorbing the calcining waste gas with <NUM>/L lime water; separating the stripped product to obtain Al foil, Cu foil, and active electrode powders. Alkaline cleaning of the calcined active electrode powders, with the following alkaline cleaning parameters: NH<NUM>OH solution with pH = <NUM>, alkaline cleaning time of <NUM>, alkaline cleaning temperature of <NUM>, filtration, separation, and drying to obtain the purified active electrode powders. Then mixing the dried active electrode powders with starch and concentrated sulfuric acid. The parameters of mixing are as follows: starch mass ratio of <NUM> %, concentrated sulfuric acid solid-liquid ratio of <NUM>/L, and obtain the mixed materials after mixing. Next, the mixed materials are sent to the high temperature reduction process. The parameters of the high temperature reduction are as follows: the atmosphere is a mixture of <NUM> % oxygen and <NUM> % nitrogen gas, the calcination temperature is <NUM>, and the calcination time is <NUM>. Finally, the product of high temperature reduction is leached and filtered with deionized water to obtain the leachate and leaching residue. The deionized water leaching parameters are as follows: solid-liquid ratio is <NUM>/L, temperature is <NUM>, leaching time is <NUM>.

In the leachate, the concentration of impurity ions such as copper, iron, and aluminum ions is all below <NUM>/L, while the concentration of valuable metal ions such as lithium, nickel, cobalt, and manganese ions is all above <NUM>/L. The leaching rate is above <NUM> %.

Soaking the waste lithium ion battery in a <NUM> % sodium sulfite solution and discharging it to a termination voltage of <NUM> V; disassembling the discharged waste lithium ion battery to obtain battery cells; mechanical force is applied to the overall crushing of the battery cells to obtain crushed materials, and the particle size of the crushed materials is sieved out to be less than <NUM> for the following calcination; raising the temperature of the crushed materials in an air atmosphere at a rate of <NUM>/min to <NUM>, heat preservation and calcining for <NUM> hour, stripping the adhesive, and absorbing the calcining waste gas with <NUM>/L lime water; separating the stripped product to obtain Al foil, Cu foil, and active electrode powders. Alkaline cleaning of the calcined active electrode powders, with the following alkaline cleaning parameters: NH<NUM>OH solution with pH = <NUM>, alkaline cleaning time of <NUM>, alkaline cleaning temperature of <NUM>, filtration, separation, and drying to obtain the purified active electrode powders. Then mixing the dried active electrode powders with starch and concentrated sulfuric acid. The parameters of mixing are as follows: starch mass ratio of <NUM> %, concentrated sulfuric acid solid-liquid ratio of <NUM>/L, and obtain the mixed materials after mixing. Next, the mixed materials are sent to the high temperature reduction process. The parameters of the high temperature reduction are as follows: the atmosphere is a mixture of <NUM> % oxygen and <NUM> % nitrogen gas, the calcination temperature is <NUM>, and the calcination time is <NUM>. Finally, the product of high temperature reduction is leached and filtered with deionized water to obtain the leachate and leaching residue. The deionized water leaching parameters are as follows: solid-liquid ratio is <NUM>/L, temperature is <NUM>, leaching time is <NUM>.

Claim 1:
A method for recovering valuable metals from waste lithium ion batteries, including the following steps:
step <NUM>: pre-treatment
short-circuit discharging, dismantling, crushing, roasting, and screening on waste lithium ion batteries to obtain active electrode powders; the waste lithium ion battery is one or more of the waste lithium nickel oxide lithium ion battery, lithium cobalt oxide lithium ion battery, lithium manganese oxide lithium ion battery, and lithium nickel cobalt manganese oxide lithium ion battery;
step <NUM>: alkaline cleaning and filtering
using alkaline solution to wash the active electrode powders, then filtering to remove copper and aluminum;
step <NUM>: drying and mixing
drying the activated electrode powder after alkaline washing treatment, mixing the dried activated electrode powder with starch with an amount of starch controlled at <NUM> - <NUM> wt.%, and then adding concentrated sulfuric acid at a solid-liquid ratio of <NUM> - <NUM>/L and stir evenly to obtain the mixed material;
step <NUM>: high temperature reduction
putting the mixed material into a corundum crucible, and then moving the corundum crucible into a tube furnace to calcine under controlled atmosphere; and wherein a calcination temperature is set at <NUM> - <NUM>, a heating rate at <NUM>/min, and a calcination time at <NUM> - <NUM>; and wherein the controlled atmosphere is a mixture of O2 and N2, and the volume fraction of O2 is controlled between <NUM> - <NUM> %;
step <NUM>: water leaching and filtration
taking out the product obtained from calcination in the step <NUM> and using deionized water to extract the leachate and leaching residue with valence metal ions, and then obtaining the leachate after filtering.