Mondo Macchina Nr. 1 - Anno 2022

n. 1/2022 45 GARDENING vo solo a determinate condizioni. Sotto la spinta del valore di mercato dei componenti e del continuo aumento della quantità di batterie da smaltire, la strada verso un’economia circolare di questi prodotti è però già aperta e offre prospettive interessanti. Uno dei sistemi di riciclo comporta, dopo la preventiva scarica, la macinazione per ottenere il materiale da cui attuare il recupero di litio, cobalto, nichel e altri metalli pesanti (non di grafite). Il processo a cui si ricorre, definito idrometallurgico, prevede un trattamento chimico di lisciviazione attuata con acidi (solforico, cloridrico o nitrico) o basi, a determinate temperature. Si tratta comunque di un processo che richiede molta energia. Un altro sistema si basa su una tecnica definita di delaminazione, attuata con ultrasuoni, che consente di staccare dall’elettrodo, sia gli ossidi di grafite, sia gli ossidi di litio, cobalto, nichel, ecc., senza bisogno di attuare la triturazione delle batterie. Quella del riciclo delle batterie è un’attività relativamente recente e in corso di evoluzione. I paesi nei quali il processo di riciclo è più avanzato sono la Cina e la Corea del sud, però anche USA e UE si stanno muovendo in questa direzione promuovendo esperienze significative. Pietro Piccarolo Weaknesses In the current lithium batteries, the electrolyte, always lithium, is in the liquid state. This can lead to overheating the battery under certain conditions, resulting in a fire hazard. Cases of self-fire of lithium batteries are not uncommon in storage areas not properly managed. One of the solutions to this problem is to make batteries with electrolytes, always lithium, but in a solid-state. This allows not only to reduce the risk of fire but also to increase the energy potential and, therefore, the duration of the use time of the batteries after each recharge. Cobalt is an essential component of the cathode of lithium batteries and thus has a growing market. The World Bank expects demand for cobalt, between now and 2050, to grow by 585%. The reason lies in the automotive sector, i.e., in the growing popularity of electric cars. As a matter of fact, in the batteries of an electric vehicle, cobalt can weigh up to 14 - 15 kg. Besides the increasing cost, of concern is that 60 - 70% of the world's total cobalt is found in the south of the Democratic Republic of Congo. The reasons for concern are the mistreatment and exploitation of labor employed in the mines and the fact that the companies used in the extraction are almost all from China. Hence the search for lithium batteries without cobalt is replaced by other metals such as nickel, iron-phosphate, manganese. Another problem created by the growth in the number of electric vehicles is the disposal and recovery of exhausted batteries. This is why Consor tia and private companies deal with the disposal of batteries and accumulators that have reached the end of their life. Battery disposal and recovery. The ways to implement proper storage of lithium batteries to avoid possible fires are the subject of regulation and guidelines by a working group consisting of the Fire Department, ENEA, and university institutes. The possibility of prolonging the life of those batteries that, although no longer able to power an electric car, still maintain a certain charge is also being evaluated. The idea is to assemble these accumulators to implement energy storage from renewable sources (solar, wind, ...). At the same time, solutions are sought for the recovery of components. Electric vehicle batteries are difficult to process due to the flammability of lithium and the fact that elements such as cobalt and even nickel have chemical-physical characteristics that require complex procedures for their recovery. This makes the process that leads to a second life of the components, destined to other applications (photovoltaic panels, for example), costly and profitable only under certain conditions. However, driven by the market value of the components and the constant increase in the number of batteries to be disposed of, the road to a circular economy for these products is already open and offers interesting prospects. One of the recycling systems involves, after prior discharge, grinding to obtain the material from which to implement the recovery of lithium, cobalt, nickel and other heavy metals (not graphite). The process used, called hydrometallurgical, involves a chemical treatment of leaching carried out with acids (sulfuric, hydrochloric or nitric) or bases at certain temperatures. It is, however, a process that requires a lot of energy. Another system is based on a delamination technique, implemented with ultrasound, which allows detaching from the electrode, both the graphite oxides and the oxides of lithium, cobalt, nickel, etc… without the need to grind the batteries. Battery recycling is relatively recent and evolving activity. The countries where the recycling process is more advanced are China and South Korea. However, the USA and EU are also moving in this direction by promoting significant experiences. Pietro Piccarolo