Bone Char

Production process similar to biochar but contains only 10% carbon. Very high phosphate content of 80% phosphate. A number of uses: water treatment/filtration, sugar refining, black pigment.

• https://en.wikipedia.org/wiki/Bone_char
• https://www.biochar-journal.org/en/ct/70-Bone-Char-made-in-Central-Park-New-York