Magnesia cement - contg ammonium salt, for reinforcing and sealing borings, giving slower hardening and resistance to magnesium

摘要

Geological formations in mining and boring processes are reinforced and sealed by means of a magnesia cement contng. a small amt. of water-sol. ammonium salt, pref. NH4Cl. The cement may also contain a small amt. of an aminoplast. The process is esp. for salt and potassium chloride mining and recovery of petroleum (gas). The compsn. is stable in presence of MgSO4. The hardening time is longer than with usual magnesia cements, and can be altered by adjusting the compsn. The cement can be removed by use of HCl or HF.