The flotation product of Bi-Semi-Concentrate containing 15% of Bi(sulfide form) and 40% of Mo(mostly as sulfide) was roasted in a Herreshoff roaster. Under the maximum temperature of 1,000℉, the concentrate was roasted without sintering phenomena. The charge of 3 ㎏ required 6-8 hrs of roasting. Practically all the molybdenite was converted to MoO₃. Roasted are was treated by the 1.5N-NaOH solution for 3-4 hrs, at 60-80℃. Na₂MoO₄ soln. contg. Mo^(+6) was filtered from the insol. residue contg. SiO₂, CuO, Bi₂O₃, Fe₂O₃. The ppt. was treated in smelter at 1,200℃ and crude Bi (97% Bi) was produced and then refined by S treatment, zincing, chlorination and aeration. Final Bi metal was 99.99% pure and over-all recovery of Bi was 90%. Na₂MoO₄ soln. was acidified by HCl to pH 2.5 and in this soln., Mo is pptd., as ammonium-sodium-polymolybdate with NH₄Cl. It was refined with 7%o NH₄Cl soln., and calcined to MoO₃. The purity of final product was 99.97% MoO₃ and the recovery of it was 85%.