Technology

Technology

  • Tidal Metal’s patented solid state Temperature Swing Vapor Pump is the breakthrough technology created by a team of PhD physicists that drives a low-cost, highly efficient salt crystallizer for heavy brines.
  • Magnesium in seawater and desalination brine can now be extracted without chemicals, without environmental impact, and at competitive prices to imports.
  • Tidal Metal's crystallization feedstock preparation uses a low temperature, efficient process that produces high purity anhydrous magnesium chloride.
  • Nothing is added to the brine, meaning seawater can be returned without harming the ocean.
  • Magnesium is 34% lighter than aluminum and 75% lighter than steel. Demand is increasing to improve transportation efficiency. For each one ton of decarbonized magnesium replacing steel in transportation, 95 tons of CO2 are avoided over the life of the vehicle.
  • Our method opens new possibilities for ZLD (zero liquid discharge) desalination, brine mining, and hydrometallurgy.
  • Salts in brines that previously went to waste can now be economically recovered.
  • Transitioning from fossil fuels to decarbonized electricity will require many times the amount of metal to be mined, but traditional terrestrial mining negatively impacts the environment. Hydrometallurgy dissolves metals into solutions that can be mined. Tidal Metal's technology will play an important role. (IEA: The Role of Critical Minerals in Clean Energy Transitions).
  • A model of Tidal Metal's modular crystallizer is shown below.

Frequently Asked Questions

How can GreenBlu's magnesium be cost competitive against Asian imports?

Our improved electrolysis feedstock production method from seawater and brines is the key to lower cost magnesium. Previous methods started with brine produced from mechanically processed solids using acid leaching, evaporation concentrated salt brines, or chemically precipitated magnesium treated with acid. The brines then underwent a number of processing steps which can include chemical purification, spray drying, calcination, dehydration, and carbochlorination to create the necessary feedstock for metal production. Each step along the way is energy intense and capital intense resulting in high metal cost. Our new adsorption crystallization technology replaces nearly all of these steps to reduce both operational and capital expenses.

Where is magnesium made now, and why is it important we reshore U.S. magnesium production?

Thirty years ago, the United States dominated magnesium production, making half of the world supply with a healthy export market. Most of the magnesium was made using seawater or the Great Salt Lake. China (87%) and Russia (5%) are now the top global producers with U.S. production falling below 4%. The United States consumes about 15% of global production making imports unavoidable.

In 2021, the only U.S. producer declared force majeure after equipment failure. Soon after a U.S. aluminum manufacturer could no longer make aluminum for soda and beer cans. Most of the widely used aluminum alloys contain between 0.5 - 5% magnesium. Current geopolitics favor the reshoring of magnesium production to reduce the risk of losing access to this Critical Mineral (as defined by the U.S. Departments of Defense, Energy and Interior).

Magnesium is used in nearly all U.S. military vehicles, particularly aircraft. Consumer electronics such as laptops and cameras also use magnesium to reduce weight. Magnesium weighs 75% less than steel and 33% less than aluminum, and would have a profound impact on carbon emissions when used to lightweight transportation.

We could build more battery electric vehicles or use less fuel in combustion vehicles if they were lighter. Magnesium is already the third most used structural metal after steel and aluminum. Many vehicles, such as the Ford F-150 have used magnesium parts for decades. We believe use would accelerate if stable domestic supplies became available once again.

Japan and the EU also each account for 15% of magnesium use. Last time we checked they also had access to seawater.

How much magnesium is in seawater? Can we really make all the magnesium we need from seawater?

Magnesium is the third most prevalent solute in seawater after chloride and sodium. There are 1.3 kilograms of magnesium metal dissolved per ton of seawater. San Diego is home to the largest seawater desalination plant in the United States, intaking 100 million gallons of seawater a day and discharging all of the magnesium as waste brine back into the ocean. That is enough to produce 180,000 tons of magnesium metal every year, enough to satisfy all of current U.S. demand. Global desalination capacity is about 500 times that of the San Diego plant, or enough for 90 megatons of magnesium each year. The global production of magnesium is currently only 1.1 megatons per year, compared to 68 megatons of aluminum and 1900 megatons of steel. To move the needle on climate, magnesium production needs to scale significantly.

How can magnesium be made without carbon emissions? How can decarbonized magnesium help with carbon emissions?

Magnesium produced in China using silicothermal reduction (the Pidgeon process) is one of the most carbon-intense metals, emitting 28 tons of CO2 per ton Mg compared to 8.5 for aluminum and 1.4 for steel. Magnesium made in this way is difficult to decarbonize because coal is used in every step of the process, from calcination (heating to very high temperatures), to ferrosilicon production using coal, to high temperature heating of the reaction chamber. It is estimated that it takes 18 tons of coal to produce 1 ton of magnesium. Calcination of dolomite CaMg(CO3)2 also directly releases CO2.

GreenBlu's magnesium has only two inputs, seawater and electricity. If the electricity is decarbonized, so is the magnesium. GreenBlu's process also uses many more low temperature processes that can be powered using heat pumps or recycled heat, amplifying the amount of energy supplied by electricity.

Lightweighting is a universal way to reduce carbon emissions in transportation. In combustion vehicles, it reduces fuel consumption. In battery electric vehicles, it reduces the amount of energy needed from the batteries, which also allows more vehicles to be made from the same supply of batteries.

A total of 95 tons of avoided CO2 emissions per ton of magnesium is possible. 28 tons are from the magnesium production, and 67 tons when the magnesium replaces steel in a vehicle over the life of the vehicle.

Transportation is the largest single sector for emissions, responsible for over 7 gigatons of CO2 emissions in 2021. It is also widely considered to be the most difficult to decarbonize. Much more than 1 gigaton a year of saving are possible with magnesium lightweighting, both through direct fuel use reduction and allowing more EVs to be build with fewer batteries.

Could there be additional uses for magnesium in the future?

Recent advances have produced magnesium alloys “approaching stainless” for corrosion resistance and improved fire resistance.  Sheet metal production and forming and extrusion advances are all expanding use in mobility. R&D in magnesium has greatly accelerated. A 2021 review paper by Czerwinski indicates that over the last decade, more than 21,000 articles have been published on Mg alloys comprising 20% of all alloy research.

Hydrogen storage is the other “killer app” for magnesium. From the "Magnesium group" of  international experts contributing to IEA's “Hydrogen Based Energy Storage”,  Yartys reports that “magnesium hydride owns the largest share of publications on solid materials for hydrogen storage”. The Fraunhofer Institute (IFAM) recently demonstrated PowerPaste, a MgH2 paste that releases 10% by mass of H2 under ambient conditions simply by mixing with water. Energy density is 10x that of lithium batteries. Spent Mg(OH)2 can be remanufactured  back into PowerPaste using the same electrolysis as magnesium production. A high hydrogen fractional mass, easy-to-transport (e.g. in existing oil tankers), easy-to-store, easy-to-use and safe form of hydrogen storage would be one crucial enabling technology needed for green hydrogen adoption.