Abstract: New organic inhibitor of three carboxyl methyl-two sodium carbonate was developed in order to solve the problems of low separating rate and heavy loss of precious metals.Mono-mineral flotation test results show that:three carboxyl methyl-two sodium carbonate can well depress pyrite，and has little effect on chalcopyrite flotation with concentration of 2.4×10-3 mol/L,pH=9~12.It can be concluded that three carboxyl methyl-two sodium carbonate can separate copper from sulphur.Copper concentrate with copper grade of 31.69% and recovery of 91.36% is obtained by flotation tests of artificial mixed ore on separation of chalcopyrite from pyrite.Materials Studio Molecular Simulation Software is brought in reagent and mineral constructed，working mechanism of three carboxyl methyl-two sodium carbonate was analysed via moleculer simulation method.The results indicated that the interaction energy between the organic inhibitor and each kind of sulfide ore is negative，pyrite interaction energy is -98.70 kJ/mol，chalcopyrite interaction energy is -10.36 kJ/mol.The organic inhibitors has stronger inhibitory effect on pyrite than chalcopyrite .IR and UV spectroscopic analysis results further validate the simulation results．

Key words: Three carboxyl methyl-two sodium carbonate, Molecular simulation, Organic inhibitors, Chalcopyrite, Pyrite