Method of recycling by-product generated in papermaking process

A method of recycling a by-product generated in a papermaking process including， pulverizing a by-product produced in a papermaking process to prepare a pulverized product， burning the pulverized product to prepare a burned product， hydrating the burned product to prepare a hydrate; and manufacturing paper from the hydrate and a paper slurry is provided， which allows reuse of by-products generated in conventional papermaking processes such as lime mud and lime kiln CaO， which is environmentally friendly as well as cost-effective， and also the level of whiteness of the by-products such as lime mud and lime kiln CaO generated in a papermaking process can be improved to that of a high-grade raw material， making it possible to also improve the whiteness of paper.