Phase formation of oil‐well cements based on chemical industry wastes

The crystalline compounds CaAl₂O₄ and Ca₁₂Al₁₄O₃₃ are reliably identified by electron microscopic and X‐ray studies of the structural and phase features of clinker, and the iron‐ and chromium‐containing phases are presented in the form of solid solutions: Ca₂Al_0.48Fe_1.52O₅ and Ca₅(CrO₄)(CrO₄)₂. This allows creating of a heat‐resistant, strong, weighted oil‐well cement for cementing “hot” oil and gas wells. It has been found that obtained materials have enhanced strength – compressive strength after 28 days of setting reaches 55 MPa, quick‐setting – initial set – 2 hours 55 minutes, final set – 4 hours 20 minutes, quick‐setting – compressive strength after 3 days of setting reaches 48.6 MPa, bending strength reaches 6.7 MPa; and are hydraulic binders with water‐cement ratio of 0.17 – 0.38; with high sulfate resistance ratio of 1.31 which is 1.5 times higher than that of Portland cement.