Lithium Slag: Hidden Dangers in Our Quest for Green Energy

Lithium-ion batteries are powering our green energy future, but there's a hidden cost. Every year, China alone produces over 10 million tons of lithium slag (LS) from smelting lithium mica. While we focus on extracting lithium, we're ignoring the environmental risks posed by other harmful substances in the slag. Researchers studied LS from 20 different companies. They found high levels of beryllium (Be), manganese (Mn), tin (Sn), zinc (Zn), and thallium (Tl) in all samples. The type of lithium mica used (zinnwaldite or lepidolite) also affected how much arsenic (As) and cadmium (Cd) ended up in the slag. The way these harmful substances behave depends on the environment. They can be more or less mobile in different conditions. For example, they move around the most in gastric fluid, followed by acetic acid, DTPA, and water. Be and Tl are particularly concerning. Their behavior changes based on how the lithium is smelted. Adding Na2SO4 creates a mineral called lazurite, which makes Be more mobile. On the other hand, too much CaSO4 stops the formation of leucite and nepheline, which makes Tl more likely to leak into water and DTPA. This research highlights the need for better regulations and safer smelting processes. As we push for more lithium to support our green energy goals, we must also consider the environmental impact of the byproducts.