Pengguna:Agung.karjono/Bak pasir/Sal amoniak: Perbedaan antara revisi

* Witty, Michael (December 2016) "Ancient Roman urine chemistry," ''Acta Archaeologica'', '''87''' (1) : 179–191. Witty speculates that the Romans obtained ammonia in concentrated form by adding wood ash (impure [[potassium carbonate]]) to urine that had been fermented for several hours. [[Struvite]] (magnesium ammonium phosphate) is thereby precipitated, and the yield of struvite can be increased by then treating the solution with [[bittern (salt)|bittern]], a magnesium-rich solution that is a byproduct of making salt from sea water. Roasting struvite releases ammonia vapors.</ref>