Concentration of gallium in the Permo-Carboniferous coals of China

Abstract

Gallium is widely used in electronic industry and its current price is about 500 US dollars pro kilogram. It has been found that its contents are very high in Permo-Carboniferous coal of China. In order to look for valuable associated gallium deposits in coal, gallium contents of 177 coal samples were determined by using inductively coupled plasma-mass spectrometry (ICP-MS) and the data of 873 coal samples from Chinese Permo-Carboniferous coalfields were collected. The results show that the average gallium concentration of Chinese Permo-Carboniferous coals is 15.49μg·g-1. There are two concentration types of gallium in Chinese Permo-Carboniferous coals: One type is that gallium has enriched to an ore deposit, and another type is that gallium is locally enriched in coal seams, but has not formed a valuable associated gallium ore deposit. The gallium concentration in Chinese Permo-Carboniferous coal may have several different sources: concentration in sedimentation stage, magmatic hydrothermal inputs and low-temperature hydrothermal fluids.