The Woodlands-based Tetra Technologies, an energy technology and services company, has picked up nearly $5.4 million in U.S. Department of Energy funding to study the recovery of rare earth elements and other critical minerals from coal byproducts in Pennsylvania.

The funding also will enable Tetra to explore converting coal byproducts, known as underclay, into clays that could be sold. In addition to the DOE funding, the company also secured about $1.3 million for a total of $6.7 million.

Publicly traded Tetra got the funding as part of a more than $17 million package aimed at designing and building facilities to produce rare earth elements, along with other critical minerals and materials, from coal resources. The Department of Energy (DOE) says these minerals and materials will go toward generating clean energy.

Rare earth elements can be derived from the country’s more than 250 billion tons of coal reserves, over 4 billion tons of waste coal, and about 2 billion tons of coal ash, according to DOE.

Clean energy fixtures like solar plants, wind farms, and electric vehicles generally require more minerals to build than their fossil-fuel-based counterparts, according to the International Energy Agency. For example, a typical electric car requires six times the mineral resources of a conventional car and an onshore wind plant requires nine times more mineral resources than a gas-fired plant.

The American Geosciences Institute says rare earth elements, a set of 17 metallic elements, also are an essential component of many tech-dependent products. These include cell phones, flat-screen TVs, and radar and sonar systems.

China is the top country for production of rare earth elements, with the U.S. far behind at No. 2.