Method of preparing heavy oil-derived anisotropic pitch for carbon fiber based on mesogen separation

A method of preparing an anisotropic pitch for carbon fiber comprising the steps of:

• (a) obtaining a primary pitch by thermally polymerizing heavy oil;
• (b) grinding and classifying the primary pitch to provide a classified primary pitch;
• (c) solvent-extracting, filtering, and drying the classified primary pitch to adjust a ratio of mesogen to non-mesogen in the classified primary pitch to provide a dried pitch;
• and
• (d) converting the dried pitch concentrated with mesogenic components into an anisotropic pitch of mesophase through a secondary heat-treatment,
• wherein a softening point of the primary pitch obtained through the thermally polymerizing is 50° C. to 200° C., and an anisotropic content of the primary pitch is 40% or less, and
• wherein the heavy oil is at least one selected from the group consisting of fluidized catalytic cracking-slurry oil (FCC slurry oil), fluidized catalytic cracking-decant oil (FCC DO), pyrolysis fuel oil (PFO), ethylene bottom oil (EBO), and de-asphalted oil (DAO).