The modern rechargeable battery is a boon to the industrial world, as these items can be recharged over and over, as opposed to disposable batteries. However, these batteries eventually go out of commission and then they have to go to waste. This is why recycling lithium batteries has been the subject of many research, as lithium type is one of the most widely-used kind of battery today.
Lithium type batteries do not last forever, and when these types of batteries go dead, they add as pollutants to the environments. Recycling lithium batteries is important, but they take too much energy and destroy essential parts of the battery. Basically, recycling these types of battery means breaking down the used cell into its basic components, only t be put back together again. It is kind of in inefficient, but it is what we have right now.
Fortunately, there are some researchers who make an effort to study how to recycle lithium batteries without breaking them down. Their methods could deliver used batteries recycled as good as new, with half the energy needed.
The Lithium Battery Composition
There are two major types of lithium batteries: Lithium ion, and lithium ion batteries which have a chemical designation of LiFePO4. As you may have assumed, these batteries contain high-grade metals like aluminum and copper. Depending on what the active material on the battery is, it may also contain transition metals like nickel and cobalt, as well as rare earth metals. You can easily see why lithium batteries can be quite expensive to make.
Finding a way to recycle them efficiently is one of the most cost-effective and practical ways to keep on using and making these kinds of batteries. Of course, prevention of future shortage of metals such as nickel, cobalt, and lithium itself require these recycling processes to be able to recover these basic components in the process.
Fortunately, current recycling processes regain a fair amount of all those mentioned resources. However these recycling methods involve long chains of processes. It is worth it right now to do them, though, as lithium batteries run most devices of the modern. Just imagine all the smart phones, tablets, and other handheld devices that use this kind of battery.
The Five-Step Process
The current process of lithium recycling involves five major steps. In order, these are discharging or deactivating the battery, then disassembling or dismantling the battery (these first two steps are especially needed in batteries used from electric cars).
The next step will be the mechanical processes, then the hydrometallurgical processes, and lastly, the pyrometallurgical processes.
1. Mechanical processes – all the dirty work. I mentioned earlier that the processes needed to recycle batteries require for the components to be torn apart and put together. The first part of that process does need mechanical processes to accomplish, an at this stage the batteries may be crushed to tiny bits and pieces. After this, the resulting material will be sorted and sieved so that individuals may be separated.
2. Hydrometallurgical processes – purification by water. This stage of the recycling process is the beginning of actually retrieving the essential elements needed to make a brand new battery. Hydrometallurgy is a process that can be used to retrieve metals from their ores. The techniques within this field are many, and some of them are as detailed as to be discussed here.
But basically, hydrometallurgical processes involve the application of aqueous chemistry so that we can retrieve metals from concentrates, ores, and other residual materials that we got from the battery that was earlier crushed by the mechanical processes.
The three major techniques in hyrdrometallurgy are leaching, solution purification, and metal recovery. Leaching, basically explained, is the used of water-based solutions to extract precious metals from metal bearing materials like concentrates and ores.
When the material is done leaching, solution purification will be required so that metal ions can be retrieved. This process also removes unwanted metal ions from the materials to be recycled. The final step, metal recovery, is the part where hydrometallurgists actually try to finally retrieve the metal contained in the recycled or residual materials.
3. Pyrometallurgy – recovery by fire. Pyrometallurgy is another method with which we can retrieve metals from lithium batteries, and it is one that we may have more common knowledge about. This method involves the use of heat and fire to recover the precious metals that is the purpose of the whole recycling process.
Pyrometallurgic processes are generally accepted as to be groupes under four major categories: calcining, roasting, refining, and smelting.
4. Calcination, in its most basic definition, is a material undergoing thermal decomposition. An example of this is the decomposition of ferric oxide to its components water vapor and ferric oxide.
5. Roasting is entirely different, which requires reaction between solids and thermal gas. This process can involve anything from chlorination, reduction, oxidation, pyrohydrolysis, and sulfation.
Refining refers to the removal of whatever impurities in the minerals to be recycled. This process involve a wide variety of processes, and may use furnaces or other workstations that involve giving off tremendous amounts of heat.
Smelting is probably the most popular method in recovering metals, at least as promoted by movies and pop culture. This one requires reactions in which at least one of the substances involved is in the molten phase. This is usually done by melting the stuff with heat from charcoal or coke, which are reducing agents that free the oxygen in the form of carbon dioxide. This way, the refined mineral or precious metal remains.
Risks Of Battery Recycling
Being that lithium batteries include potent chemicals, there are risks and dangers involved with recycling them. These can be classified into chemical dangers, electrical dangers, and potentially dangerous interactions with other chemicals. There is also the problem of water sensitivity. A chemical called lithium hexafluorophosphate, which is commonly used as an electrolyte material, can react quite dangerously with water.
This is because they form hydrofluoric acid. One common solution to this is to dissolve the whole thing in solvent to prevent water reactions. Once determined safe, the material are then separated from the electrodes so that they will be ready for the rest of the recycling processes.
Current State Of Lithium Recycling
The current recycling techniques do not really extract lithium from used lithium ion batteries any more, as the various types of lithium batteries also require a myriad of methods with which to extract the element. It has also been found out that recycling lithium is actually five times more expensive than actually mining it, so retrieving this element using current method seems really impractical.
However, there are efforts to recycle lithium batteries using only fifty percent of the energy required by current recycling methods. These ways of recycling that they are currently researching are claimed to produce compounds that are ready to use in new batteries, instead of breaking down the stuff into individual components and putting them back together again.
What’s most wasteful about crushing batteries is that they destroy the structure of battery cathodes, which is valuable. A lot of time and effort is needed to make million s of these structures on a daily basis, and current recycling methods crush them only to put them back together again. It is a rather impractical process, as you may have already learned reading most of this article.
However, Zheng Chen, a professor of engineering in University of San Diego, California, is part of a research team that aims to develop recycling methods that preserve the beautiful microstructure of lithium Ion batteries during the recycling process.
The way they achieve this is by first cycling lithium batteries until they lost fifty percent of their storage capacity. They then separated the cathode material from the aluminum foil substrate and then soaked it in a heated lithium solution. The next step is to dry the solution and then quickly superheat it to 800 degrees Celsius.
The final step is to cool it down very slowly. They believe that this process replenishes the lost lithium ions as while at the same time also preserving the microstructure of the battery. The best part is that the new recycled batteries have the same lifespan, storage capacity, and charging time as the originals.
At least two other companies based in the U.S have been working on a similar recycling method, which does not involve crushing the battery into individual components first. These companies are called OnTo Technologies based in Oregon, and Farasis Energy based in San Francisco.
Recycling lithium batteries is a must in today’s world, seeing as the demand for these kinds of batteries only grow exponentially every single day. Besides powering smart phones, tablets, and other conveniences of modern life, lithium batteries are also expected to be a stable of the electric car.
Current methods of recycling may be viable for now, however inefficient. Still, the search for more cost-effective recycling methods may be one of the most anticipated breakthroughs we will need to watch out for in the coming years.