I found this recipe on Barry J. Fuller's "Living In Paper" website:
A typical starting formula for a 200-gallon batch is
- 160 gallons (727 liters) of water,
- 60 pounds (27 kilograms) of paper,
- 1 bag or 94 pounds (43 kilograms) of Portland cement and
- 15 shovelfuls or 65 pounds (29 kilograms) of sand.
The sand adds thermal mass, reduces flammability and shrinkage, and packs down the slurry for a denser, stronger block.