Manufacturing method of petroleum needle coke for graphite electrode

摘要

Provided are a petroleum needle coke having a sufficiently low coefficient of thermal expansion (CTE) and achieving suppression of puffing and a method of producing the petroleum needle coke. Specifically provided is a petroleum needle coke for a graphite electrode. A powder of the petroleum needle coke having a grain size of 75 µm or less is heated at 2,800°C in an argon gas atmosphere to yield a graphite powder having a loop structure that is formed by folding a stack including a plurality of stacked graphite crystal sheets, the graphite crystal sheet includes carbon atoms arranged in a plane, the graphite powder has an edge surface of the closed loop structure of the stack, and a loop formed by two adjacent layers on an innermost periphery of the stack has a stack angle of 5° or less. The stack angle is an angle formed by a tangent line at a point A and a tangent line at a point B, where each of the point A and the point B is 10 nm apart from a vertex of the loop and on the corresponding layer of the two adjacent layers along the basal plane, and the vertex of the loop is an outermost point on the edge surface of the loop on the innermost periphery.