Advertisement
U.S. markets close in 2 hours 47 minutes
  • S&P 500

    5,250.75
    +2.26 (+0.04%)
     
  • Dow 30

    39,762.07
    +1.99 (+0.01%)
     
  • Nasdaq

    16,373.02
    -26.51 (-0.16%)
     
  • Russell 2000

    2,127.59
    +13.24 (+0.63%)
     
  • Crude Oil

    82.79
    +1.44 (+1.77%)
     
  • Gold

    2,242.70
    +30.00 (+1.36%)
     
  • Silver

    24.98
    +0.22 (+0.90%)
     
  • EUR/USD

    1.0801
    -0.0028 (-0.26%)
     
  • 10-Yr Bond

    4.1940
    -0.0020 (-0.05%)
     
  • GBP/USD

    1.2631
    -0.0007 (-0.06%)
     
  • USD/JPY

    151.3450
    +0.0990 (+0.07%)
     
  • Bitcoin USD

    70,650.17
    +1,441.70 (+2.08%)
     
  • CMC Crypto 200

    885.54
    0.00 (0.00%)
     
  • FTSE 100

    7,952.62
    +20.64 (+0.26%)
     
  • Nikkei 225

    40,168.07
    -594.66 (-1.46%)
     

Have scientists discovered why China is so rich in rare earth elements the world's smartphones need?

Geologists in southern China say they have isolated a series of critical factors that could make it easier to find rare earth elements used in hi-tech consumer goods such as smartphones.

China has more than 80 per cent of the world's reserves of heavy rare earths such as terbium, dysprosium and holmium concentrated in a few provinces to the south of the country.

The reason for the concentration is one of the biggest puzzles in geology, but researchers at the Guangzhou Institute of Geochemistry in Guangdong province say the answer may be found in a combination of clay deposits, acid rain and granite that is distinctive to southern China.

Professor He Hongping and his colleagues came to the conclusion by testing the interaction between rare earths and different types of clay. Through their research they found that kaolinite " or china clay " was the best at absorbing rare earths from water.

The clay, named after Gaoling village near Jingdezhen, a centuries-old ceramic production centre in east China's Jiangxi province, is a raw material for porcelain production.

While kaolinite is found in many countries, those places do not have rare earth deposits " probably because of the lack of acid rain, He said.

"You need the right environment."

He said that rocks that contained tiny amounts of rare earth elements weathered faster in an acid environment, but the acidity could not be too high or the rare earth might run off before it could be captured by the clay.

Rainwater with the right natural acidity often occurred in areas around 20 degrees latitude, such as southern China, he said.

The last step was to locate the source rock. Granite formed in volcanic eruptions between 100 million and 200 million years ago is considered to be the main source of rare earths.

He said that part of the Pacific tectonic plate containing rare elements might have been forced under the Eurasian Plate and was pushed to the surface as magma that formed rocks.

Recent discoveries in Vietnam, Australia and North Carolina in the United States conformed to the Guangzhou team's theory, but there was still more research to do, he said.

"Rare earth deposits are quite unlike minerals such as copper. Sometimes they occur in this mountain but not in another nearby with almost the same geological features. Sometimes they occur in one half of the mountain but not in the other."

With China and the US engaged in a trade war, and Beijing cutting taxes on mining companies looking for these elements, the pressure was on to unlock the secrets of China's abundant rare earth deposits, he said.

Dr Huang Fan, associate researcher with the China Geological Survey, said the Guangzhou discovery would help geologists to find more rare earths.

Most rare earth mines were located along the borders between provinces such as Guangdong and Jiangxi, but recently there were discoveries on a plateau in Yunnan province, where few geologists believed rare earths could be found, he said.

"There are many more rare earth deposits out there waiting for us."

This article originally appeared in the South China Morning Post (SCMP), the most authoritative voice reporting on China and Asia for more than a century. For more SCMP stories, please explore the SCMP app or visit the SCMP's Facebook and Twitter pages. Copyright © 2019 South China Morning Post Publishers Ltd. All rights reserved.

Copyright (c) 2019. South China Morning Post Publishers Ltd. All rights reserved.

Advertisement