Phase distribution of thallium in pyrite and effect of carbonate in the procedure of thallium release
铊在黄铁矿中的相态分布及碳酸盐在其释放过程中的作用

Phase thallium in pyrite was analyzed by inductively coupled plasma mass spectrum (ICP-MS) with sequential extraction procedure. The results showed that thallium of pyrite existed mostly in silicate phase and mineral structure by acid-exchangeable state and the proportion were 58.3% and 25.1% respectively. Thallium existed less in pyrite (FeS_ 2 )_ by oxidable state with 11.2%,and lest in iron oxides by reducible state with 5.4%.The release and migration behaviors of thallium in pyrite were mainly derived from acid-exchangeable and oxidable state thallium at natural environment. The surface reaction in pyrite was investigated by the diffuse reflectance FTIR spectroscopy (DRIFTS), and it was found that the surface hydroxyls in pyrite were strengthened in the process of surface oxidation; moreover, the surface dissolution and surface acidification were indicated. A thallium release mechanism was proposed that the dissolution-adsorption precipitation equilibrium was occurred, and the equilibrium was under the control of both neutralization reaction of carbonate and surface oxidation of pyrite, and finally decided the release and migration of thallium.