Tikalon Blog by Dev Gualtieri

Critical Materials

April 22, 2024

Human culture has been defined by materials to the extent that archaeologists have named some periods of human activity by their premier materials. In the so-called three-age system, we've lived in the Stone Age, which ended about 4000 BC; the Bronze Age, which started around 2500 BC, when metalworking was first practiced; and the Iron Age, which started around 1000 BC. The proposed Anthropocene, the present age of man, could be defined by increased trace elements, notably radionuclides, in the geological record. The mass of synthetic materials now outweighs all Earth's biomass.[1]

Since gold is the least reactive metal, it occurs in nature as the metal, itself, so it was the first metal used by man. After gold, primitive man discovered ways to release other metals from their ores by heating. The ancients were able to smelt silver, mercury, copper, lead, tin, and finally, iron. Bronze, an alloy of copper and tin, was a stronger metal than copper, and it had sufficient properties to launch the Bronze Age.

Hesiod, Works and Days, lines 150-151, scanned from the author's copy of ref. 2. The translation is "Their armor was of bronze, and their houses of bronze, and of bronze were their implements: there was no black iron."[2]

Iron smelting, the extraction of iron from its common ores, is much more difficult than the extraction of the other metals since it requires higher temperature. The reduction of the common iron ore, hematite (Fe₂O₃), using carbon as a reducing agent is straightforward; viz.,

2Fe₂O₃ + 3C -> 4Fe + 3CO₂

This so-called carbothermic reaction uses readily available materials, but it happens at higher temperatures than encountered for the smelting of the other metals known to the ancients. These temperatures were achieved after development of bloomery furnaces.

The 150th anniversary of the Periodic Table was in 2019, proclaimed the International Year of the Periodic Table of Chemical Elements (IYPT2019) by the United Nations General Assembly. Russian chemist, Dmitri Mendeleev (1834-1907), organized all the chemical elements known in 1869 into a periodic table based on atomic weight.[3]

(Wikimedia Commons image of Dmitri Mendeleev in 1887, modified for artistic effect.)

Fewer than half of the 118 elements of today's periodic table were known to Mendeleev. The present plethora of 118 elements has given scientists a huge palette of materials with which to create compounds of technological importance. Most prominent among these are alloys for high strength permanent magnets, lithium cathodes for rechargeable batteries, and high temperature alloys for gas turbine engines and turbine generators. The essential problem is extraction of large quantities of these sometimes trace elements from the Earth's crust.

The uneven distribution of needed elements adds geopolitics to the extraction problem. Notably, China produces 60 percent of the rare earth elements needed for such things as NdFeB magnets used in motors and generators, phosphors and catalysts.[4] China also imports rare earth elements from other countries to process nearly 90 percent of worldwide rare earths into end products.[4] As shown in the following table, lithium is likewise concentrated in just a few countries.

**Lithium Production in 2021**
Country	Metric Tons	Percent
Australia	55,416	52
Chile	26,000	25
China	14,000	13
Argentina	5,967	6
Brazil	1,500	1
Zimbabwe	1,200	1
Portugal	900	1
United States	900	1

The United States Department of Energy has designated 54 materials as being of critical importance.[6-7] These are listed in the following table and include lithium and all of the rare earth elements with the exception of scandium and promethium.

**United States Critical Minerals 2023**
Aluminum	Gallium	Rhodium
Antimony	Germanium	Rubidium
Arsenic	Hafnium	Ruthenium
Barite	Holmium	Samarium
Beryllium	Indium	Silicon
Bismuth	Iridium	Silicon Carbide
Cerium	Lanthanum	Tantalum
Cesium	Lithium	Tellurium
Chromium	Lutetium	Terbium
Cobalt	Magnesium	Thulium
Copper	Manganese	Tin
Dysprosium	Natural Graphite	Titanium
Electrical Steel	Neodymium	Tungsten
Erbium	Nickel	Vanadium
Europium	Niobium	Ytterbium
Fluorine	Palladium	Yttrium
Fluorspar	Platinum	Zinc
Gadolinium	Praseodymium	Zirconium

Human lust for raw materials is not expected to slake any time soon. As reported by the Guardian, an analysis by the United Nations finds that worldwide extraction of raw materials is expected to increase by 60% by 2060.[8] This follows on the nearly 400% growth seen since 1970.[8] Not surprisingly, raw material extraction is responsible for major environmental impact in biodiversity loss, air pollution, and water stress.[8] Building an environmentally friendly future is also problematic, since an electric vehicle has nearly ten times the critical material content of a conventional internal combustion engine automobile.[8]

European Union annual per capita material consumption

European Union statistics show that Europeans consume 15 metric tons of materials per person annually.[8] The consumption ranges from 7 metric tons per person for The Netherlands to Finland's 46 (see figure).[8]

Finland also generates the most per capita waste (20,993 kg), about seven times that of the least wasteful country, Croatia (1,483 kg).[8] The average waste generation of a European Union citizen in 2020 was 4,815 kg.[8]

(Map from the European Union Eurostat showing the annual raw material consumption. Click for larger image.)

Critical Materials

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