As the demand of electrical equipment, vehicles and gadgets like mobiles, laptops and power banks is increasing, demand of batteries being an integral part of these items and in particularly the demand of metals used in these batteries is increasing. The metals used is manufacturing these batteries are commonly marked as black mass metals.
As the extraction of these metals from virgin sources is difficult, expensive and energy extensive, recycling these materials from black mass requires relatively lesser energy resulting in significant reduction in the carbon footprint.
An Overview of the Emerging Battery Market
Batteries are becoming most reliable alternate energy source for running our daily use products like laptops, tablets, mobile phones, iPods, power banks and many other things.
Considering only Smartphones, there are currently over 7.2 billion smartphones worldwide. More than 40 million electric vehicles are now on road globally and these numbers are considerably increasing. The usage of laptops, tablets, toys and many other products is also increasing.
The extensive use of these products globally at one end has resulted in significant increase in electronic waste containing plastics and precious metals and on the other side is creating demand of metals used in batteries. Read in detail about extracting precious metals from electronic waste recycling in our blog.
What are Lithium Ion (Li-ion) Batteries?
Lithium ion batteries are most commonly used batteries and metals used in these batteries are not available in abundance unlike many other energy resources like petroleum, coal, gas and thermal energy.
The most commonly used metals used in thee batteries are, Lithium Li, Cobalt Co, Cadmium Cd, Lead Pb, Zinc Zn, Manganese Mn, Nickel Ni, Silver Ag and Mercury Hg. Extracting of these metals from earth’s core is relatively expensive, need substantial amount of energy and environmentally harmful.
Additionally, recycling of these materials, typically called black mass recycling, being relatively easy and energy efficient can save energy cost, reduce harmful wastes and contribute to circular economy. Moreover, improvements in recycling technologies is becoming essential to sustainable transition to a low-carbon and circular economy.
How are Batteries Recycled?
Recycling process typically involves following steps;
Inspection and Discharging
Normally, batteries are not completely discharged during use and retain some electrical charge at the end-of-life point. Therefore, at the recycling facility, the batteries are inspected for temperature, external damage, leakages, and residual electrical charges. So the electrical charge is zeroed using discharge load units for safe dismantling and crushing phases of recycling.
Disassembly
After discharge, the battery is dismantled manually to separate the lithium-ion cells from the battery. The separation includes extraction of the battery management system (BMS), power electronics, and the thermal management system and removal and sorting of wires, cables, and connectors. Some of these parts are reused as spare parts for new batteries or further processed into raw materials.
Size reduction and separation
The battery cells are crushed and shredded into parts. Some facilities skip the dismantling process and shred the battery packs whole after discharging them. The shredded particles are separated through magnetic separation, electrostatic separation, liquid-based sorting and vibrating.
The metals recovered at this stage typically include copper, aluminum, and steel. These metals, as well as the recovered plastic, are sorted and stored for further processing. After the plastic and metal particles have been removed from the shredded mass, what is left is a black, powdery substance known as black mass which contains lithium and many other metals.
Black mass refining
Black mass is a powdered material comprising of a combination of cathode and anode materials and other components like electrolytes and conductive additives. This material contains a mixture of lithium, nickel, cobalt, manganese, copper, and other recoverable metals, many in their oxide form. The two most common techniques for extracting these metals from black mass are pyrometallurgy and hydrometallurgy.
Pyrometallurgy
Pyrometallurgy involves incinerating and consequently melting of black mass in a smelter to very high temperatures of up to 1,400°C. This technique relies on the difference in temperatures and thermodynamic reactions between the constituent elements in black mass and added reducing agents to separate the materials. During this process, the graphite and any remaining electrolyte in the black mass burn off. The nickel, cobalt, and copper content form a mixed metal alloy, while the lithium and manganese form slag that floats to the top of the melt.
This process normally consumes large amount of fuel to achieve the high temperatures. It also requires sophisticated treatment processes to prevent severe environmental pollution.
The main drawback of pyrometallurgy is that metals extracted from incineration need further processing which needs additional energy and metal losses.
Hydrometallurgy
Hydrometallurgy starts with dissolving the black mass in an acid to form a solution, followed by extraction through solvent extraction and ion-exchange method that selectively recovers the constituent metals step by step from the black mass.
Floatation
Unlike conventional recycling methods, floatation methods are the most integrated and improve recycling technologies which not only extract metals from used batteries but also remove impurities cutting the recycling cost by 50% and lower carbon emissions to almost 90%.
Social Efforts to Support Battery Recycling
Battery recycling needs a community engagement support to educate people through social media campaigns by government and the manufacturers highlighting the environmental impact of improper battery disposal and the importance of recycling batteries.
Additionally, battery recycling bins can be installed at public places to support battery collection facilities making it possible to save cost of sorting.
Black Mass recycling in future Perspective
With the electronics market is expanding globally, the requirement of batteries, particularly their components and metals used. The electric vehicle market is also expanding rapidly, with global sales exceeding 10 million units every year which at one side is raising need for environmentally safer battery production and on the other side relying on recycled batteries.
Implementation of more advanced energy efficient black mass recycling techniques is crucial for circular economy and help reduce reliance on virgin raw materials.
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