How do you recycle lithium batteries?

Waste batteries contain a large amount of heavy metals and electrolyte solutions such as waste acid and waste alkali. If discarded at will, heavy metals exuded from used batteries will cause pollution of water bodies such as rivers, rivers, lakes and seas, which indirectly threaten human health. Therefore, the recycling and disposal of waste batteries not only treats the source of pollution, but also realizes the recycling and reuse of resources.

At present, the power battery is mainly in the form of nickel-hydrogen battery and lithium battery. Hybrid battery currently uses nickel-hydrogen material. However, some technical performances of nickel-hydrogen battery are close to the theoretical limit value, so it is not considered as the future development direction. In contrast, Lithium ion batteries due to their high working voltage, small volume, have no memory effect, small self-discharge, and the advantages of long cycle life, widely recognized. The waste lithium ion battery usually cobalt containing 5% ~ 15%, 2% ~ 7% of lithium, nickel 0.5% ~ 2%, and its relatively high recycling value. Lithium-ion battery contains six toxic materials such as lithium fluoride phosphate, can cause serious pollution to the environment and ecosystems, cobalt, manganese, copper and other metals by accumulating effect also by food chain harm humans, extremely dangerous. Along with the lithium ion battery application is more and more widely, recovery of valuable metals in lithium ion batteries, reduce pollution to the environment, alleviate the problems such as resource scarcity, has important social significance and economic significance.

1 waste lithium ion battery of valuable metal recycling technology

1.1 dry process technology

Dry process is isolated from the lithium ion battery reduction roasting cobalt, aluminum, cobalt leaching separation and acetylene black.

Japan's SONY Corporation and Sumitomo metal mining company, cooperative research from waste lithium ion secondary battery recovery of cobalt and other technology, its process first burned the battery and again after the screening to iron and copper, heat the residual powder and soluble in acid, organic solvent extraction can be proposed cobalt oxide [2].

ChurlKyoungLee [3], such as the waste lithium ion battery first, then heat treatment, the combustible material into a gas, leaving LiCoO2.In the constant temperature water bath, add in nitric acid, hydrogen peroxide solution LiCoO2, makes the leaching rate of Co and Li achieves 85%.

Dry process is relatively simple, but the energy consumption is higher, other ingredients and electrode in the electrolyte solution combustion easy to cause air pollution.

1.2 wet technology

Wet method is based on inorganic acid solution leaching the valuable components from the waste batteries, to be recycled in a certain way.

The lithium ion secondary battery positive electrode material was leached with hydrochloric acid at 80 ° C, and the leaching rates of Co and Li were all greater than 99%, and then Co was extracted with PC-288A (2-ethylhexylphosphoric acid-mono-2-ethylhexyl ether). After stripping, the cobalt is recovered in the form of cobalt sulfate. Further, a sodium carbonate solution was added to form a lithium carbonate precipitate, and the recovery rate was close to 80%.

KudoMistuhiko et al. [5] leached the lithium ion battery positive waste with acid, added an amphoteric metal to the leachate, changed Co2+ to Co, and then removed the amphoteric metal to obtain the metal Co.

Xiaofeng Wang, [6] the first electrode materials dissolved in dilute hydrochloric acid, then adjust pH = 4, selective precipitation of aluminum hydroxide, and then adjust the pH to 10 or so, the cobalt, nickel complexes generated ammonia, then pass into the O2 to Co2 + and Ni2 + oxidation, and the solution by ion exchange resin, Co and Ni with oxalic acid salt precipitation down again.

Wu Fang [7] with alkali dissolving battery materials, removal of about 90% aluminum in advance, and then use - H2SO4 + H2O2 system leaching residue, after leaching filtrate contained Fe2 +, Ca2 +, Mn2 + impurities, such as solvent extraction with P204 cobalt and lithium mixture, then with P507 solvent extraction separation of cobalt, lithium, cobalt sulfate after back extraction, extraction liquid precipitation recycling lithium carbonate, lithium a recovery was 76.5%.

Energy consumption is bigger also, wet process and the technological process is long, the equipment requirement is high, high cost, resource recovery rate is low.

1.3 ionic sieve method and treatment of lithium ion batteries

In 2003, Wuhan University of science and technology developed a use lambda - MnO2 ionic sieve separation from waste lithium ion battery recycling new methods of lithium, which has been granted a patent for invention. For step: remove disintegration of battery shell, immerse the battery core make it fully dissolved in hydrochloric acid; Regulating system of pH > 10, filtered to get material liquid lithium ion; With lambda - MnO2 ionic sieve material liquid processing, the lithium ion selective adsorption separation, and then use hydrochloric acid elution was carried out on the adsorption in the lithium ions in ionic sieve, evaporating eluent lithium chloride, to join in eluent Na2CO3, heating concentration after the lithium carbonate precipitation [7].

1.4 Bioleaching process

The so-called microbial leaching process is a technique in which a useful component of a system is converted into a soluble compound by a microorganism and selectively dissolved to obtain a metal-containing solution, thereby separating the target component from the impurity component, and finally recovering the useful metal [8].

Compared with the traditional battery recycling technology, biological leaching has less infrastructure investment, low operating cost, little pollution to the environment, etc. But this is a relatively new subject, there are many problems need to solve, such as species selection and cultivation, leaching condition control, mechanism of biological leaching, etc.

1.5 Other recycling technologies

LiCoO2 electrode by electrochemical reduction technology will Co3 + reduction of Co2 +, lithium released from LiCoO2 solid structure at the same time, it avoids the introduction of other chemicals and cause subsequent treatment of complications [9].

D.-S. Kim et al. [10] conducted an investigation of LiCoO2 repair separation based on the mechanism of "dissolution-precipitation", repaired and simultaneously separated LiCoO2 material, and the method steps were simple.

2 waste lithium battery recycling countermeasure and the suggestion

2.1 Start with the battery producer and do a good job of sorting and recycling

Battery producers should contain hazardous waste batteries are identified, suggests that the kind and content of the harmful material, in order to recycling, at the same time, producers will continue to improve the battery production technology, reduce the content of the harmful ingredients such as heavy metals in battery.

2.2 intensify propaganda, improve environmental protection and consciousness

At present, people's understanding of waste battery pollution is insufficient, and it has not formed a sense of environmental protection for consciously collecting waste batteries. Although the recycling of used batteries has attracted the attention of relevant departments in recent years, designated fixed-point units for recycling have been designated, but the results have been minimal. Therefore, we should vigorously promote and raise people's awareness of the significance of recycling and utilization of waste batteries. Relevant group organizations should also carry out corresponding practical activities to cultivate people's sense of social responsibility to protect the environment and form a good environment for environmental protection in the whole society.

2.3 perfecting the laws and regulations, to establish perfect management system

For the realization of the products of low mercury and mercury free batteries, on battery management policy in our country has established standard for mercury free batteries and related ministries and commissions from the restrictions on battery mercury levels, these rules have the waste battery pollution from the source control. Relevant government departments to formulate management measures which accords with the situation of our country and the concrete implementation rules, through legislation requiring producers and sellers recycling the waste products, and at the same time, establish and improve the recycling system as soon as possible, to create all sorts of convenient conditions for the recycling of waste batteries.

2.4 strengthen technology research and development

It is necessary to increase the research on the application of waste battery recycling technology and develop new technologies with low investment, less pollution and high treatment efficiency. At the same time, the content of harmful components is controlled from the source of battery production, and the development of environmentally friendly rechargeable batteries is accelerated, and the amount of discarded batteries is reduced.

In the future, the research on resource technology of waste lithium-ion batteries will be more comprehensive and mature. We should strengthen the environmental management of waste batteries and make the processing technology develop in the direction of low cost and no secondary pollution. At the same time, we will take the road of developing new green and environmentally friendly batteries, so that production and recycling will form a virtuous circle, truly benefiting the people and harmless to the people and nature.

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