amounts of bone china is produced using these synthetic alternatives rather than bone ash. Fertilizers Bone ash can be used alone as an organic fertilizer or it can be treated with sulfuric acid to form a "single superphosphate" fertilizer which is more water soluble: Ca3(PO4)2 + 2 H2SO4 + 5 H2O → 2 CaSO4·2H2O + Ca(H2PO4)2·H2O Similarly, phosphoric acid can be used to form triple superphosphate, a more concentrated phosphorus fertilizer which excludes the gypsum content found in single superphosphate: Ca3(PO4)2 + 4 H3PO4 → 3 Ca(H2PO4)2 Metal casting Bone ash is used in foundries for various purposes. Examples include release agents and protective barriers for tools exposed to molten metal, and as a sealant for seams and cracks. Applied as a powder or water slurry, bone ash has many unique characteristics. First of all, the powder has high thermal stability, so it maintains its form in extremely high temperatures. The powder coating itself adheres to metal well and does not drip, run, cause much corrosion, or create noticeable streaks. Using the bone ash is easy as well, as it comes in a powder form, is easy to clean up, and does not separate into smaller parts (therefore requiring no extra mixing). Metallurgy Bone ash is a material often used in cupellation, a process by which precious metals (such as gold and silver) are removed from base metals. In cupellation, base metals in an impure sample are oxidized with the help of lead and are vaporized and absorbed into a porous cupellation material, typically made of magnesium or calcium. This leaves the precious metals which do not oxidize behind. Bone ash's extremely porous and calcareous structure as well as its high melting point makes it an ideal candidate for cupellation. Analysis of bone ash The chemical analyses of three samples of ceramic grade bone ash: See also Cremains - composed partially of human bone ash References Inorganic compounds Ash Organic fertilizers Animal products Types of ash