Stabilization-solidification treatment of mine tailings using Portland cement, potassium dihydrogen phosphate and ferric chloride hexahydrate

► Cement gives rise to alkaline conditions determining the release of heavy metals. ► Cement alone does not permit the obtaining of a product complying with legal limits. ► KH2PO4 allows a significant decrease in Pb due to the formation of stable compounds. ► The combined use of KH2PO4 and FeCl3 solves the problem of Pb, As and P release. ► Solidification tests with additives produce monoliths in accordance with law limits.