Rheology, modified compositions exhibiting stress-dependent fluidity, modification agents therefor, and methods of making same

Abstract

A method of making a rheology modified aqueous composition, particularly useful for drilling, milling and mining applications, is disclosed. The method includes admixing, with a clay and water, a material or materials whose constituents substantially conform to the proportions of the empirical formula M′mM″n(OH)(2m+3n+qa+br)(Aq)a(Br)b.xH2O, where M′ represents at least one divalent metal cation and m is an amount of from greater than zero to about 8; where M″ represents at least one trivalent metal cation and n is an amount of from greater than zero to about 6; where A is an anion or negative-valence radical that is monovalent or polyvalent, and a is an amount of A ions of valence q, provided that if A is monovalent, a is from greater than zero to about 6, and if A is polyvalent, a is from greater than zero to about 3; where B is a second anion or negative-valence radical that is monovalent or polyvalent, and where b is an amount of B ions of valence r and b is from zero to about 1; provided qa+br cannot be greater than 2m+3n, and provided that qa cannot equal 2m+3n; further provided that (2m+3n+qa+br) is less than 3; and where xH2O represents excess waters of hydration, with x being zero or more. Calcined hydrotalcite and hydrotalcite-like materials are particularly preferred as starting materials. Optionally, an aluminum oxide, a nitrogen-containing compound, or both may be added. The resulting composition is preferably an elastic solid exhibiting stress-dependent fluidity, desirable temperature resistance, lubricity, inhibition of reactivity, relatively low cost, and pressure resistance. A dry composition and method of making are also disclosed.

Dependencies are inferred from the claim text.