| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive printing paper contributing to the recycling of papermaking sludge, such as used newspaper deinking froths, etc., and excellent in terms of printability, opacity, and whiteness.SOLUTION: The printing paper of the present invention is a printing paper to which a filler has been internally added, wherein the filler uses, as a raw ingredient, a papermaking sludge including used newspaper deinking froths as a main component and includes regenerated particles obtained past dehydrating, combusting, and firing steps in a state where the content of calcium carbonate within the regenerated particles is 65 mass% or higher. It is desirable to form a combusted matter at the combusting step by feeding an oxygen-containing gas and discharging an exhaust gas having an oxygen concentration of 5 vol.% or above and 11 vol.% or below. It is desirable for the combustion temperature of the combusting step to be lower than 600°C. It is desirable for the ratio of decomposition, into calcium oxide, of the calcium carbonate included within the papermaking sludge after the combusting step to be 30 mass% or below. |
