Researchers at the Lawrence Livermore National Laboratory and Penn State have developed new research that shows how a protein isolated from bacteria and can contribute to a more environmentally friendly way to extract metals that are important for technologies such as smartphones and electric car batteries and to separate them from other metals and each other. Domestic supply of rare earth metals this method could help develop from industrial waste and electronics due to being recycled.
To meet the increasing demand for rare earth elements for use in emerging clean energy technologies, several challenges in the supply chain needs to be addressed. This includes improving the efficiency and making the environmental burden less severe of the extraction and separation process for these metals. The researchers demonstrated a new method in this research using a natural protein that could increase the extraction and separation of rare earth elements from low-grade sources, including industrial wastes.
The US currently imports most of the rare earth elements it needs. A new focus has been given on establishing a domestic supply from unconventional sources, including industrial waste from burning coal and mining other metals and electronic waste from cell phones and many other materials. The rare earth elements are vast but are considered as a low grade because with many different metals they are mixed. The amount present is too low for traditional processes to work well.
The current method of extraction and separation of harsh chemicals is labor-intensive, sometimes involves hundreds of steps, produces a high volume of waste, and it’s a high cost. A bacterial protein called calmodulin is used in this new method. This protein is a billion times better in binding with rare Earth elements than other metals.
How the protein is used –
- It is 1st immobilized onto tiny beads within a vertical tube commonly used in industrial processes. Then liquid source material is added.
- To rare Earth elements, proteins then bind into the sample. By this, the rare-earth remains in the tube and the remaining liquid is drained off.
- Then by changing the conditions, the metals unbind from the protein, which can be drained and collected.
- Individual rare Earth elements could be separated by carefully changing the conditions in sequence.
More details about the research –
Even in a very complex solution where less than 0.1% of the metals are rare Earths, the research team, by using this method, has extracted and then separated a grouping of the lighter rare Earths from a group of the heavier rare Earths in one step. The rare earth has to be separated into individual elements to be used in technology and this makes the separation step simple.
For example, the research team separated yttrium (Y) from neodymium (Nd). Both are abundant in coal byproducts and primary rare earth deposits with greater than 99% purity. For many cycles, the protein can be used. It offers an eco-friendly alternative to current methods. The researchers believe that their method of low-grade sources can be used efficiently, especially for extraction and separation of the far more valuable and the rarer heavy rare earth.