There are many different ways of recycling the different batteries available in the world today. However, they all have the same objective, which is the recovery of useful materials. For a complete list of today's recyclable batteries, please visit our section Current Recyclable Materials - Battery.
In this section, we will focus only on the recycling process of Lithium ion (Li-Ion) batteries (dry-cell rechargeable type). In order to recycle this specific type of battery, the battery has to undergo several processes. The result of applying these processes to Li-Ion batteries is the recovery of metal contents. The entire recycling of Li-Ion batteries can be summarized into five general different levels.
Level 1 - Pyrolysis
Once the batteries are recollected and grouped together, it will first go through the process of Pyrolysis. During this level, the batteries are heat treated at temperatures of up to 700° Celsius. At this high temperature, water and mercury evaporate. The vaporized water and mercury are then mixed together with some carbonized organic components (such as paper or plastic) and passed through an afterburner that burns at temperatures of over 1000° Celsius. At this extreme temperature, dioxins and furans are eliminated from the gases. After this, the gases are then led into the next level, which is into the exhaust-gas purification plant.
Level 2 - Exhaust-gas Purification
After the Pyrolysis process, the gases that come into level 2 are extremely hot. The exhaust-gas purification process is responsible for cooling the gases and for condensing mercury so it can be used at a later level. In more detail, during level 2, the gases are cooled (to around 4° Celsius) and washed with a wet-chemical process (that consists of circulating water). Solid materials are removed during this washing/cooling process and mercury is condensed out as a metal.
Level 3 - Metal Recovery
The metallic components recovered in level 2 are now going to go through another process which will further purify the metal. The metals are inserted in the induction furnace at a temperature of 1500° Celsius. At this temperature, iron and manganese remain in the melt to form Ferro-manganese. Other substances in the metal, such as zinc, vaporizes in this process (similar to level 1). The zinc gas is then recovered in the zinc condenser. During this process, Ferro-manganese and the slag (residue) are removed every four hours.
Level 4 - Waste-water Purification
During this level, the water used in the previous levels (mostly in level 2) is purified before it is dumped into the sewage system. Cyanide, fluoride, and heavy metals are removed from the water through filtration. The solid materials obtained after this process are then sent back to level 1 for reprocessing while the now clean water is finally dumped into the sewage system.
Level 5 - Mercury Distillation
In order to obtain the mercury from the waste, the waste is heated to over 360° Celsius. At this temperature, mercury vaporizes and condenses again as pure mercury in a condensation column. Before the gases are release into the environment, one last step is needed to make sure that all harmful chemicals are removed. A carbon filter is used and the remaining traces of mercury in the gas are finally eliminated completely.
[Courtesy of: Batrec.]
Section I: Introduction
Section II: Present (YOU ARE CURRENTLY IN THIS SECTION)
Section III: Future
Complete Table of Contents
Reference