Thorium and the rare earth value chain - a nuclear renaissance solution?

The rare earths industry was initially built on monazite, a common by- or co-product of placer mining between 1950 and 1964. Thorium bearing rare earth element phosphate ores (Th-REE-Ps), principally monazite, were the primary commercial source of rare earths until the mid-1960s. From 1965 to 1984, these Th-REE-P materials supplied nearly half of the world's rare earths requirements, and nearly 100% of the world's heavy rare earth elements. Th-REE-Ps and Th-U-REE-Ps (rare earth-bearing apatites from phosphates that typically contain thorium and uranium) are mineralogically superior to low-thorium bearing minerals like bastnaesite because they typically contain recoverable quantities of all 16 rare earth elements (promethium, although included in the lanthanide series, does not occur naturally in the earth's crust). These materials were also typically a low- or no-cost by-product of mining some other commodity, such as titanium, zircon, iron ore or phosphates. Rare earth minerals like bastnaesite that do not meet the source material threshold have several disadvantages, including: low-thorium levels that equate to low (sub-recovery) levels of heavy rare earths; the fact that the minerals are directly mined means that 100% of the mining cost must be covered from the sale of the rare earths extracted (versus China, where more than 70% of rare earths production is a byproduct of iron ore mining); and, the typical chemical distribution of bastnaesite is disproportionately apportioned to elements with the lowest economic value, typically >80% cerium and lanthanum.