Chinese rare-earth ores

The rare earth content of Chinese iron rare earth ore deposits occurring in three regions is given in Table 1.13. 

Bastnasite LnFCOs Monazite (Ln, Th)P04 (richer in earlier lanthanides) Xenotime (Y, Ln)P04 (richer in later lanthanides). In addition to these, there are Chinese rare earth reserves which amount to over 70% of the known world total, mainly in the form of the ionic ores from southern provinces. These Chinese ion-absorption ores, weathered granites with lanthanides adsorbed onto the surface of aluminium silicates, are in some cases low in cerium and rich in the heavier lanthanides (Longnan) whilst the Xunwu deposits are rich in the lighter metals the small particle size makes them easy to mine. The Chinese ores have made them a leading player in lanthanide chemistry. 

China s weathered-crust elution-deposit rare earth ore, called ion-adsorption rare earth ore, is unique. This type of ore was discovered in 1969 in the Jiangxi Province. There are two types of deposits light REE type (A) and heavy REE type (B). It was found also in other Chinese provinces Fujian, Hunan, Guangdong, and Guanxi. The provinces where these deposits are found are given in Fig. 2.20. The... 

Then there is also the so-called balance problem . The rare earths are found in nature as mixtures. The mixture found depends on the ore mineral, the type of ore, and the location of the deposit. Bastnaesite and monazite are minerals which are rich in the LREEs, whereas xenotime and the South-Chinese ion-adsorption clays are rich in the HREEs. Also, the REEs decrease in abundance with increasing atomic number Z. Now the balance problem is the balance between the abundance of the rare earth elements in ores and the demand on the economic markets (Binnemans et al. 2013). 

While in the USA environmental regulations were very strict and labor costs relatively high, Chinese companies profited from a combination of low labor costs and lax environmental regulations. Also, the largest rare earth mine in China at Bay an Obo not only produces rare earths but also iron ore, which provides another stream of income which covers the mine s fixed costs (Gholz 2014). 

Mining of rare earths is generally divided into three historic eras (i) Monazite-placer, (ii) Mountain Pass and (iii) Chinese. The advent of the Chinese era (mid-1980s) was marked by availability of rare earths at prices that undermined most other mining operations, resulting in cessation of mining activities, although ores were still processed. The Chinese have aroimd 55% of all known rare earth deposits and control over 90% of world supply. Marine deposits may provide a considerable increase in reserves in the future. ... 

The abundance of mercury in Earth s cmst is estimated to be about 0.5 parts per million. That makes it one of the 20 least common elements. It very rarely occurs as an element. Instead, it is usually found as a compound. Its most common ore is cinnabar, or mercuric sulfide (HgS). Cinnabar usually occurs as a dark red powder. It is often called by the common name of vermillion or Chinese vermillion. 

---