Las tierras raras (I): ¿Qué son las tierras raras? · La March

The Historical Context of Chemical Discoveries in Sweden

Introduction to Carl Axel Arrenius

• The narrative begins in late 17th century Sweden, focusing on a young artillery officer named Carl Axel Arrenius stationed at a fortress near Stockholm.

Education and Early Interests

• Arrenius received training in chemistry, particularly related to gunpowder production, which included lessons on inorganic chemistry.

Discovery of Tungsten

• While exploring a nearby village, Itervi, he discovered a heavy stone that intrigued him; he named it "tunsteno de Iterby" due to its weight.

Initial Analysis and Collaboration

• He consulted chemists who believed the stone contained "Volframio," an element recently identified by Spanish scientists.

The Role of Johan Gadolín

Scientific Investigation

• Arrenius sent the stone to Swedish scientist Johan Gadolín for analysis; Gadolín conducted various tests leading to the identification of an oxide compound.

Limitations of Technology

• At that time, technology was insufficient for isolating elements like yttrium from their oxides, marking a significant limitation in chemical research.

Emergence of Rare Earth Elements

Transition from Alchemy to Chemistry

• This period marked the transition from alchemy to modern chemistry, with notable figures like Antoine Lavoisier categorizing elements into groups.

Classification of Elements

• Lavoisier's classification included categories such as earth and oxides; this laid groundwork for future discoveries including yttrium.

Significance of Itervi Mine

Historical Importance

• The Itervi mine is recognized for yielding several elements named after it: lithium, terbium, erbium, and ytterbium.

Recognition by Scientific Associations

• In 1989 and 2019, the American Mineralogical Association and European Union honored Itervi’s contributions with commemorative plaques.

Discoveries Beyond Itervi

Expansion to Other Mines

• Attention shifts to another mine in Basnas where additional rare earth minerals were discovered during World War II due to their strategic importance.

Contributions from Local Scientists

• Hisinger owned the Basnas mine; his son made significant discoveries that contributed further to understanding rare earth elements.

Key Discoveries in Rare Earth Elements

Collaborative Efforts

• Vercelius analyzed new samples leading to discoveries such as cerium and lanthanum alongside other collaborators.

Progression Towards Purity

• By mid-century, pure forms of yttrium and cerium were achieved while others remained inseparable until later advancements.

Global Expansion of Rare Earth Element Research

International Discoveries

• A Russian engineer discovered new deposits outside Sweden which diversified sources for rare earth minerals globally.

Understanding Abundance vs Rarity

Clarification on Terminology

• Despite being termed "rare," many rare earth elements are more abundant than traditionally scarce metals like platinum or gold.

Advances Through Spectroscopy

Technological Innovations

• The invention of spectroscopy allowed scientists to analyze elemental spectra but initially led to erroneous conclusions due to sample purity issues.

Challenges in Elemental Identification

Misleading Results

• Many claimed discoveries turned out false due to impurities affecting spectral readings; George Urben emerged as a key figure clarifying these findings through rigorous testing.

Evolution of Periodic Table Understanding

Mendeleyev's Contribution

• Mendeleyev's periodic table helped organize known elements systematically while paving the way for future discoveries among rare earth elements.

Mosley's Impact on Element Classification

Order Restored

• Henry Mosley established atomic numbers based on positive charges within nuclei resolving confusion regarding element placement within the periodic table.

Quest for Element Number 61

Race Against Time

• Following Mosley’s work led scientists worldwide searching desperately for element number 61 amidst claims it might not exist naturally.

Discovery Amidst Nuclear Research

Promethium Unveiled

• During nuclear research efforts linked with atomic bomb development led researchers discovering promethium—named symbolically after Prometheus reflecting energy harnessing themes.

Characteristics & Applications

Unique Properties

• Promethium stands out as radioactive with limited natural occurrence yet holds potential applications across various fields including energy generation technologies.

Understanding Rare Earth Elements

Origin of the Term "Rare Earths"

• The term "rare earth" originated before the periodic table was established, as these elements were discovered through mineralogical processes and retained their name despite being more accurately classified as lanthanides plus lithium and scandium.

Classification Confusion

• There is no universally accepted classification for light and heavy rare earth elements; some classify based on gadolinium, while others use samarium or neodymium depending on regional practices, leading to confusion in mining contexts.

Commonly Recognized Light Rare Earths

• The most commonly recognized light rare earth elements include lanthanum, cerium, praseodymium, neodymium, and sometimes samarium due to their abundance in mined minerals.

Importance of Clarity in Reporting

• News reports on rare earth mining should specify which elements are being referenced to avoid ambiguity caused by differing classifications across regions and industries.

Acronyms and Commercialization of Rare Earth Elements

Common Acronyms

• Key acronyms related to rare earth elements include REE (Rare Earth Elements), LREE (Light Rare Earth Elements), HREE (Heavy Rare Earth Elements), and REO (Rare Earth Oxides).

Commercial Practices

• In commercial contexts, rare earth minerals are processed into oxides for sale; thus, production figures often refer to tons of REO rather than raw minerals.

Historical Contributions of Carl Auer von Welsbach

Innovations in Lighting

• Carl Auer von Welsbach significantly improved gas lighting by using thorium and cerium filaments that enhanced brightness; this innovation marked a pivotal moment in urban illumination during the late 19th century.

Impact on Society

• His invention led to widespread adoption of brighter gas lamps across cities like Vienna before electricity became prevalent; it notably delayed the transition from gas to electric lighting until the 1920s.

Development of Modern Ignition Devices

Creation of Ferrocerium

• Auer also invented ferrocerium for lighters after observing its spark-producing properties when scraped; this innovation revolutionized fire-starting methods compared to traditional matches.

Economic Success from Discoveries

Financial Gains from Rare Earth Discoveries

• Auer's discoveries led him to wealth and nobility status under Emperor Franz Joseph I due to his contributions in isolating praseodymium and neodymium among other rare earth elements.

Advancements in Television Technology

Introduction of Europium

• In the mid-20th century, europium was identified as essential for color television screens, marking a significant advancement that transitioned televisions from black-and-white displays to color broadcasting.

Research Trends in Rare Earth Applications

Scientific Publications Growth

• Analysis shows a dramatic increase in scientific publications regarding rare earth elements since 1961, indicating ongoing research into their properties and applications across various fields.

Global Research Landscape

Country-Specific Research Output

• China leads with approximately 17,500 articles published on rare earth research followed by the USA with around 8,000 articles; funding sources vary significantly between countries impacting research output.

Notable Figures in Spanish Science

Contributions by Blas Cabrera Infante

• Blas Cabrera Infante made significant contributions studying magnetic moments of rare earth ions while collaborating with notable scientists like Einstein during his visits to Spain.

Transitioning Research Focus

Shift from Europe to China

• The focus of research has shifted from Europe initially towards the United States but is now predominantly centered in China due to increased investment and interest in material sciences involving rare earth elements.

Applications of Rare Earth Elements Today

Diverse Uses Across Industries

The primary applications today include magnets used extensively across various technologies such as electric vehicles, smartphones, medical devices including MRI machines due to their unique properties enhancing performance efficiency.

Importance of Rare Earth Elements

Overview of Substitutability and Demand

• The only fully substitutable rare earth element is promethium, while samarium, praseodymium, and neodymium are about 50% substitutable.

• Elements like ytterbium, thulium, europium, lanthanum, and yttrium are not substitutable at all.

• The significance of these elements has increased due to their growing use in various industries.

Production and Consumption Balance

• A curious aspect of production balance is that if a mineral contains cerium and samarium, optimizing for one may lead to excess of the other.

• This imbalance necessitates storage solutions for surplus materials based on market demand.

Geopolitical Implications

• Rare earth elements are considered geostrategic; their importance will be discussed in more detail in future sessions.

• A graph from the U.S. Department of Energy highlights the critical nature of certain rare earth elements for clean energy between 2015 and 2025.

Critical Elements for Clean Energy

• By 2025, neodymium, dysprosium, terbium, europium, and yttrium were identified as critically important for clean energy applications.

Historical Context and Cultural Significance

• An exhibition titled "Rare Earth" showcased the discoverers of these elements alongside their applications.

• The curators suggested we have entered an era defined by rare earth elements following historical ages such as stone, bronze, and iron.