A US patent published 3-11-2016 presents production of a PIN flame retardant and surface protection product from aluminium dross, a waste substance generated during aluminium metal smelting and re-melting, using the low aluminium content dross which cannot be recycled in the aluminium process.
Dross particles, generally 2mm or smaller, are reacted with an acid such as phosphoric acid. The resulting self-priming mixture is then applied to articles before drying for 12-24 hours, resulting in a fire safety treatment. The product can be used on materials such as wood fibre board, polyester ceiling batt, polystyrene, and can also provide rust protection for steel.
“Fire retardant, insulation material and surface protectant”, US patent 3-11-2016 n° 20160319134 http://patents.justia.com/patent/20160319134