Abstract: Based on the Density Functional Theory（DFT)，the electronic structure and surface energy of {100}，{110}，{101} cleavage surfaces of cassiterite were investigated by First-principles calculation with Materials Studio(MS) 7.0，and the adsorption of hydroxyl ions onto {100} surface was also researched.The calculated results showed that，compared with {101} surface，{100} and {101} surface which were the most common exposed surfaces for cassiterite，owned lower surface energies.The hydroxyl ions adsorption on cassiterite surface mainly attributed to the negative charged oxygen atoms bonding with the five folds Sn atoms in mineral surface.The 5 fold tin atoms which owned danging bonds was the active center of surface.The calculation results provide a fundamental theoretical basis for the further development of new cassiterite collectors.

Key words: Cassiterite, First-principles calculation, Surface energy, Hydroxyl ions