PURPOSE: To provide a process for the recycled use of sludge as a resource without necessitating large plant investment or operation energy of the process by producing unburned tile in high efficiency.

CONSTITUTION: This unburned tile is produced by mixing 60-90wt.% of a material containing molten slag obtained by melting sewage sludge as a main component of aggregate, 10-40wt.% of calcium aluminate powder passing through 100 mesh sieve and 0.1-5.0wt.% of an inorganic pigment, kneading the mixture with water and solidifying the kneaded mixture. Sewage sludge is effectively utilized as a recycled resource by this process. The unburned tile can be produced without investing in large-scale apparatuses such as press and kiln or consuming energy for forming and burning process. The time necessary for the production is remarkably shortened compared with conventional process for the production of burned tile.