Uncovering the Key Features of Dysprosium Flows and Stocks in China
I have just come across this paper: Uncovering the Key Features of Dysprosium Flows and Stocks in China
Shijiang Xiao, Yong Geng, Hengyu Pan, Ziyan Gao, and Tianli Yao Environmental Science & Technology 2022 56 (12), 8682-8690.
There are 14 lanthanide elements, with yttrium making 15 although it is not strictly an "f element" although its chemistry is very similar. Most lanthanide (aka "rare earths" ) deposits are dominated by just two, cerium and yttrium, with the other, with the lighter 6 including cerium as well as lanthanum, praseodymium, neodymium, samarium, and gadolinium dominating the remainder. (Europium can behave differently than most lanthanides and is sometimes depleted in ores. Promethium does not occur naturally; it is radioactive, with a short half life, but can be obtained, in very small quantities - because of its high neutron capture cross section - from used nuclear fuels.)
Dysprosium is a "heavy" lanthanide, and as such is relatively rare. Nevertheless it is in high demand, hence this article.
The largest application, as one can see from the open abstract, is to build wind turbines, which after decades of cheering and the destruction of huge tracts of wilderness to make industrial parks, remains a trivial form of energy, even though the fate of the planet's atmosphere has foolishly been bet on them.
From the opening text of the full article:
China has the largest REE reserve with an amount of approximate 44 megatons (Mt, 1 Mt = 1,000,000 tons), accounting for 37% of the global reserve in 2019. (14) As for Dy, it is estimated that the global dysprosium oxide (Dy2O3) reserve is 1.62 Mt, referring to 1.41 Mt Dy metallic equivalent. (14) China has the largest Dy reserve with an overall amount of 1.23 Mt, accounting for 87% of the global reserve. (14) Such reserve exists for several common rare earth minerals, such as monazite, xenotime, bastnasite, and ion-adsorbed clays (IACs). In particular, the Dy-rich IACs are distributed only in Southern Chinese provinces, such as Jiangxi, Fujian, Guangdong, and Hunan. However, the accurate flows and stocks of China’s Dy cycle remain unclear.
Material flow analysis (MFA) is one widely recognized method to characterize material flows through the anthroposphere. (15) MFA is capable to track material flows through a specified system boundary and identify how one material transforms and accumulates over its lifecycle based on the principle of mass balance. (16) This method has been employed to analyze most mineral elements and several REEs within different regions and periods, such as aluminum, tungsten, graphite, and neodymium. (17?20) As for the Dy cycle, the existing MFA studies mainly focus on the Dy flows associated with NdFeB in Japan, (1) the impacts of the increasing demand for neodymium (Nd) and Dy on the supply and demand of the host metals and other companion REE in wind power in the US, (12) Dy stocks and flows in NdFeB magnets among 18 various products and its recycling potential by 2035 in Denmark, (21) and the effectiveness of reducing Dy demand from low-Dy NdFeB magnets and promoting NdFeB magnets recycling in Japan for 2010–2030. (22)
The term used in this opening statement, "clean energy" is one I personally find objectionable. There's nothing "clean" about wind and electric cars.
I recently attended an online lecture put on by the Irving Institute at Dartmouth by a scientist whose name escapes me about the "recycling" handwaving that goes on, by the way. She pointed out that in use materials are not available for recycling, and where use is growing rapidly the demand must be met by mining.
Some graphics from the paper:
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Some frame work on the flows:
(1) Domestic flows: domestic flows are the basic Dy flows, covering mining, fabrication, manufacturing, and use stages. They are calculated based on the amounts of primary products, intermediate products, final products, and Dy contents in different products. Various Dy forms are transformed into unique metallic Dy flows. These final products and their Dy contents are listed in Tables S1 and S2.
(2) Trade flows: trade flows reflect the Dy import and export amounts at five stages with various forms. These Dy-containing products are coded by the Harmonized Commodity Description and Coding System of China and listed in Table S3. The trade flows are equal to the traded product amounts multiplied by their corresponding Dy contents.
(3) Loss flows: in this study, the Dy losses are assumed to occur in the R&S stage and fabrication stage, with figures of 10 and 30% respectively. (1,26) These loss flows are calculated by multiplying the production amounts and their loss rates.
(4) Supply-demand flows: Dy flows are calculated by the top-down approach in the R&S stage, while the bottom-up approach is used to estimate the demand for Dy in the fabrication and use stages. Hence, there is a mismatch between the Dy-containing concentrate supply and compound demand, and this gap is considered to be composed of hibernating stock and illegal mining.
(5) In-use stocks: a bottom-up approach is applied to estimate the in-use Dy stocks through the accumulation of net flows since the base year of 2000. (27) The calculation equations are listed as...
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According to text in the paper China does not have enough dysprosium to meet its internal demand. (This is surprising to me.)
Several policy recommendations are made since China is both the largest producer and consumer of dysprosium.
One is to crack down on illegal mining - the isolation of lanthanides and their separation is very dirty chemistry, and when wildcatted, it is even worse.
Others are to increase recycling - although as noted above - recycling will not meet supply in a case of rising demand, rising demand being operative in the dysprosium supply.
I would imagine that most people do not think about this element. It's obscure. It is rather amazing however, to recognize how much depends on access to it, even in the case where the world comes to its senses and stops building wind turbines.
The light lanthanides are all fission products; the heavy ones (those past gadolinium) are not.
= new reply since forum marked as read
I guess that is why hearing from people from diverse backgrounds (and geographic areas) is valuable.
The proposal to send the spent nuclear fuel and other radioactively contaminated items was actually a compact that was agreed to by George W. Bush while he was governor and Rep. Bernie Sanders, among others. I was living in Austin at the time, but the proposal did receive coverage in the alternative media publications there because the residents of Sierra Blanca are primarily poor Hispanics with little political power.
And thanks for posting the thread, I don't have many opportunities to use that minor in chemistry from decades ago. I even picked up on the "f element" jargon in the first sentence referring to atomic orbital hybridization. 
