The alkaline feed of crude sodium tungstate obtained from the caustic fusion of black tungsten ore was neutralized to a pH value near 9 to eliminate Si as routine, then the resulting feed was directly used as the external aqueous phase without eliminating P, As and Mo. Through a single stage batch liquid membrane process at room temperature for 5 min under optimum operation conditions obtained by an orthogonal test, APT directly crystallizes in the internal aqueous phase with 99.87% yield and the quality attained was the first grade of a national standard; meanwhile the pH value of the effluents was lowered to 6-7 in itself suitable for direct discharge and without W(VI) lost out of the raffinate. Finally, a continuous counter-current process of a single stage for a pilot plant was proposed.