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Heavy rare earths do not come from a conventional orebody. They come from weathered granite where the metal ions cling loosely to clay, and they are recovered by washing a salt solution through the hillside. The grade is tiny; the strategic weight is enormous.
- Malzeme
- Dysprosium
- Çeşit
- Ion-adsorption clay, very low grade, unusually rich in heavy rare earths
- Nereden başlıyor
- China — Weathered granite hills in Jiangxi, Guangdong and Fujian
Adım adım ve sınırdan sınıra
China · Jiangxi and Guangdong elinde State-consolidated producers (Devlet üreticisi)
Leaching the hill in place
Ammonium sulfate solution is injected into the weathered granite and collected downslope. The rare-earth ions swap places with ammonium on the clay and come out in solution. Nothing is blasted and, in modern practice, little is dug.
Geri kalanına ne oldu: Older, uncontrolled in-situ leaching left serious groundwater and slope-stability damage, which is much of why the industry was consolidated under state control.
Neden burada: This deposit type needs a specific granite, a specific climate and millions of years. It is not a matter of looking harder elsewhere.
China · On site elinde Producers (Kimyasal)
Precipitating a mixed carbonate
The pregnant solution is precipitated into a mixed rare-earth carbonate — the intermediate everything downstream starts from.
Neden burada: Concentrating before transport, as always.
China · Ganzhou, Jiangxi elinde China Rare Earth Group and affiliates (Rafineri)
Separating the heavies
Solvent extraction, but far harder than for the light rare earths: dysprosium, terbium, holmium and erbium are even more alike than neodymium and praseodymium, so it takes more stages and more patience.
Geri kalanına ne oldu: Terbium, yttrium, gadolinium and the rest come out alongside. Yttrium is by far the largest fraction; dysprosium and terbium are the ones everyone actually wants.
Neden burada: Heavy separation capacity is concentrated here to a degree unmatched by any other material in this atlas.
China · Magnet plants elinde Magnet manufacturers (Üretici)
Diffused into a magnet's grain boundaries
Rather than alloying dysprosium throughout the magnet, it is painted on and diffused into the grain boundaries where it does the most good. The technique cut dysprosium use per magnet several-fold.
Geri kalanına ne oldu: This is substitution by engineering rather than by chemistry — same performance, a fraction of the scarce element.
Neden burada: Grain-boundary diffusion is a process advantage held by a small number of manufacturers.
Germany · Traction motors and turbines elinde Motor manufacturers (Üretici)
A motor that can get hot
Without dysprosium a neodymium magnet begins losing strength around 80 °C. A traction motor or a turbine nacelle routinely runs hotter than that. 15 kg is enough for several thousand car motors.
Neden burada: A few kilograms of a metal from a Chinese hillside is what lets an electric motor survive a summer traffic jam.
Bu çalışılmış bir örnektir. Belirtilen bir başlangıç miktarını, yayımlanmış tipik verim ve geri kazanım oranları üzerinden takip eder; dolayısıyla oranlar doğrulanabilir niteliktedir; belirli bir sevkiyatın kaydı değildir. Güzergâh bilgileri — hangi ülkeler, hangi işlemler ve malzemenin neden başka bir yerde işlenemeyeceği — kamuya açık raporlardan derlenmiştir.