1. The problem statement, all variables and given/known data I need to determine the minimum solvent and number of stages in an extraction process. What I need to do first is drawing the phase envelope (miscibility gap curve) inside the ternary system triangle diagram. I am given the equilibrium values of A,B and S (solvent) in both raffinate and extract phases. 2. Relevant equations 3. The attempt at a solution All examples I have the triangle is given with the curve inside in the first place. So I couldn't figure out how to draw it but I know I need it first I guess. I tried to draw it with raffinate and extract graph next to it but failed to do that.