Occurrence and geological controls of gallium in coal from Xingjiashe, Gujiao Mining District, Shanxi

Gallium is an important basic and strategical material,and occurs in coal as a rare and dispersive metal element with various bound form.Based on the data from coal resource exploration,the authors in the paper dis-cussed the occurrence and geological controls on the gallium in the Permo-Carboniferous coal seams from the Xingjiashe,Gujiao Mining District,Shanxi.The results show that the gallium in Xingjiashe coals is 15.87×10^-6 in weighted average content,and is 0.5 to 3 times more than mean content of the gallium in global coals.The gallium content tends evidently to reduce with depth of coal seams,and also is specifically relative to the coal ash yield and component,sulfur content and coal seam thickness.These indicate that gallium in Xingjiashe coals occurs mainly in clay mineral,might be enriched in the peat bog with the conditions of both stronger hydrodynamics and weaker reduction.Moreover,the activity of lithosphere during coal accumulation might impact the enrichment of gallium in coals through some ways.