Namrata Singh, Department of Chemistry and corresponding author; Abhishek Maurya and Vibhuti Rai, Department of Geology, University of Lucknow
The price of global development that we pay heavily is at the cost of the earth’s environment. With every passing year, the development and growth perish millions of trees and create permanent damage to the environment in which we live. And, therefore, we have to look for all such domains in which we can find such technologies and materials which are multiple times efficient and at the same time less energy consuming. One such substance that Mother Earth has provided us is called as Rare Earth Elements (REE) which may provide us with a ray of hope for sustainability in the exploitation of natural resources, on which, the development of the future can be anticipated.
Although known for decades, rare earth elements can be called as smart material which is not only energy efficient but also available in a respectable amount in different parts of the world. The devices that are made with the help of REE are extremely energy efficient and it can be appropriately called “A watt save is a watt generated”. This material can be called as truly a green material which is still under the experimental stage for its efficiency in the development of electronic devices, state-of-the-art devices, aircraft technology, power-efficient electronic circuits, and space technology, among so many others.
Rare earth elements occur as a hidden treasure in most of the metallic ores and associated rocks for which not much significance was attributed in the past seven decades ever since the industrial revolution. However, lately, in the last decade and a half, REE has proven to be the wonder material that is going to rule material science on account of its significance to its usage in the state-of-the-art technologies especially in the electronics industry as well as many other industries where advance chemicals are needed as an innovative material such as nanoparticles, fullerene and polyester nanoparticles. In addition, organic nanoparticles are going to control the industry.
Since REEs are used in so many cutting-edge technical fields, there has been a very rapid rise in demand for them. The main applications for REE primary products include the production of high-purity individual rare earth compounds, petroleum and environmental protection catalysts, mixed metals, and polishing powders. In addition, in Metallurgy, permanent magnets, terfenol, magnetic refrigeration, magneto-optic materials, ceramics, electronics, optical, phosphors, nuclear, hydrogen storage and superconductors are some of the specific disciplines in which REE is used. Its applications span from commonplace items (such as lighter flints, glass polishing compounds, and vehicle alternators) to cutting-edge technology (lasers, magnets, batteries, fiber-optic telecommunication cables, windmills, etc.). Even leading-edge technology requires these Rare Earth Magnets (For example high-temperature superconductivity, safe storage and transport of hydrogen for a post-hydrocarbon economy, environmental global warming, and energy efficiency issues). REE helps technologies perform with less weight, less emission, and less energy consumption thanks to their special magnetic, luminescent, and electrochemical qualities. As a result, they improve their efficiency, performance, miniaturisation, speed, durability, and thermal stability.
As of now, the exact REE deposits in the country are still not known and proper investigation and mapping of such occurrences as well as new occurrences have not been attributed for a long time. But in recent times, the total control and restriction on the export of REE by China, a country with maximum production, has been taken up by the world’s leading countries to be a matter of great concern as most of the state of art technologies are dependent on REE.
China served as the primary source of REE up to about ten years back. However, following China’s draconian limits on REE supply, there has been a sharp increase in exploration activity worldwide, including in India, in order to keep up with the continuously rising demand for REEs from diverse sources. In this regard, carbonatite and alkaline rocks, riverine placer deposits and beach placer deposits have been found to contain the majority of the REE resources in India. Inland placers of both Light REE and Yittrium + Heavy REE-bearing commercial minerals can be found in streams draining the Chhotanagpur Granite Gneiss Complex (CGGC) topography in central India, both along the stream's course and on its banks and flood plains. In the CGGC terrain, placers with the potential to contain REE minerals have been discovered along the course of the following rivers: (a) Deo, Girma, Halwai, and Pojenga in the Jharkhand districts of Kolebera and Simdega; (b) Siri, Baljora, and Champajharia in the district of Jashpur; and (c) Padri, Baghro, Nawadih, Bhairopur, Goga, Sukhnaiya and Dumhat rivers in Balrampur and Sarguja districts of Chhattisgarh.
Additionally, there are modest to significant REE resources in other regions of the nation: (i) Granitic soils of the Darba area in Bastar district, Chhattisgarh; (ii) stream sediments along the Vasava and Ujol rivers in Baroda district; the Joz river in Panchmahal district, Gujarat; (iii) stream sediments near the Dharmawaram area in Karimnagar district; (iv) the Pathapalem area in Mehbubnagar district, Telangana; (v) soils near the Tonnur Pandavpura granitic bodies, Mandya and Hassan districts, Karnataka; (vi) Soils in Rangampetta (South Arcot district) and Kulampatti (Salem district), Tamil Nadu; (vii) Remaining soil in the Kanyaluka area, near the Singhbhum shear zone, Jharkhand; (viii) Sands along the banks of the Kameng River and East Kameng district, Arunachal Pradesh. In addition to these resources, the Siwana ring complex in Rajasthan's Per-alkaline granites, rhyolites, microgranites, and tuffs hold potential as primary resources for REE. Additionally, attractive REE concentrations have been found in apatite-magnetite veins found in pegmatites in the Kasipatnam area of the Visakhapatnam district, Andhra Pradesh.
Exploration over a number of decades revealed significant LREE reserves in the monazite and other related minerals found in the beach sands of Kerala, Tamil Nadu, Odisha, and Andhra Pradesh. For the previous few decades, IREL, a public sector project of DAE, has been mining some of these deposits for REE, including Chavara in Kerala, Manavalakurichi in Tamil Nadu, and Chhatrapur in Odisha. India's coastline is thought to contain a monazite deposit of about 12 million tonnes.
Green material for the sustainable future of India
As enumerated in the above paragraphs, it would be appropriate to call REE as a green material because it reduces the carbon footprint by huge numbers by providing us with highly efficient products with the least energy consumption. For greater sustainability of the earth, such material can be a game changer. Although, India has been exporting iron ore in millions of metric tons to several countries including Japan without realizing that they were only selling the Iron ore but huge reserve hidden in the form of REE has also got exported without any talk about it! It was never discussed by the government agencies and in the process, millions of tons of REE got exported without being paid for it and that has depleted our own huge resources in a clandestine manner. It is time that the government realises the significance of the issue and stops any export of such ores that contain REE. This issue also requires to be considered under the Atmanirbhar Bharat program of India where such high-tech substances need greater attention for the country’s supremacy on worldwide resources.
(Authors express their gratitude to Prof Ajai Mishra, Head of the Department of Geology, University of Lucknow, for providing the facilities for this article)