The study was performed with low-grade limestone, which is used to make cement or is disposed of due to its low CaO content. In this study, the optimal condition of limestone with which to manufacture precipitated calcium carbonate (PCC) and limestone in fiber was determined through in-situ reactions. The best firing condition is with slaked lime with rapid cooling after 2 h of firing at $1000^{circ}C$. In addition, the content of CaO can be increased by sorting the low-grade limestone using a 200 mesh filter, and the optical quality of old newspaper (ONP) was similar when using both low-grade and high-grade limestone. Also, controlling the particle size of PCC is an important factor pertaining to the optical characteristics of paper.