Cementitious compositions comprising a hydraulic cementitious material, a compound selected from the group consisting of a polyhydroxy aromatic compound, a polycarboxylic acid-containing compound or a salt thereof, ascorbic acid or a salt thereof, or a combination thereof, and a particulate material or a water soluble silicate-containing material that interacts with the compound are described herein. The polyhydroxy aromatic compound can be a water soluble compound having from two to thirty hydroxyl groups. The particulate material can exhibit a particle size distribution, wherein at least about 90% by weight of the particles have a diameter of less than 2 mm. Suitable particulate materials include nanoparticles and microparticles. The cementitious compositions can be used to form building materials. The cementitious compositions are especially suited for inhibiting corrosion of reinforcing steel bars embedded in concrete mixtures. Methods of making and using the cementitious composition are also disclosed.

In one embodiment, the methods include introducing a treatment fluid including an aqueous base fluid, at least one viscoelastic surfactant, a divalent salt, a metal salt; and a metal oxide into a wellbore penetrating at least a portion of a subterranean formation; and allowing the treatment fluid to at least partially set in the subterranean formation.

Cementing in a subterranean formation may include, activating an extended-life cement composition by mixing at least the extended-life cement composition with a liquid activated pozzolan additive comprising a carrier fluid and an activated pozzolan, wherein the extended-life cement composition comprises water, pumice, hydrated lime, and a set retarder; introducing the extended-life cement composition into a subterranean formation; and allowing the extended-life cement composition to set to form a hardened mass in the subterranean formation.

A use of a thiosulfate as a retarder for a cement paste comprising a magnesium phosphate cement.

A novel cement composition for 3D printing including has 90% to 99.5% by weight of one or more cements selected from a Portland cement, an aluminous cement, a sulphoaluminous cement and a prompt natural cement; and has 0.5% to 10% by weight of a silicoaluminous filler having a specific surface area of at least 5 m.sup.2/g, as well as a method for implementing the composition.

A combination of retarders and regulators for hydration reaction of cementitious binders including clinkers based on Ye'elimite. Set retarders are calcium complexing agents, consisting of sugar acids, sugars, sugar alcohols, hydroxycarboxylic acids, phosphates, phosphonates, borates and amines. Regulator general formula (I) is ##STR00001##
where M is H, NH.sub.4 or chosen from monovalent or divalent metal of groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of periodic table of elements, where M is a divalent metal, a second equivalent of RSO.sub.3 is present, and M is chosen from group consisting of H, NH.sub.4, Li, Na, K, MgX, CaX, or NiX with XRSO.sub.3, and R is chosen from H, NH.sub.2, OH or from hydrocarbon chain with 1-18 C atoms which may be substituted by N and/or O and/or which may be linear or branched and/or which contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic moieties.

A method for precious metal extraction comprises contacting a precious metal-containing ore with an improved cyanide extraction agent under conditions suitable for the formation of a coated precious metal-containing ore where the extraction agent comprises (i) a cement and (ii) a cement retarder; and contacting the coated precious metal-containing ore with a cyanide solution to form soluble precious metal complexes. A composition for gold extraction comprising: (i) a cement (ii) a cement retarder and (iii) an inorganic cyanide salt.

A method of making a setting type compound by injecting an activator compound into a plaster compound wherein the activator compound tube is coaxial and within the plaster compound tube, each at the same flowrate, the same pressure and the same viscosity. The cross sectional transverse areas of an annulus containing the plaster compound and the hole in the annulus containing the activator compound are the same.

A method of producing magnesium cement. The method may comprise mixing water at a temperature of between approximately 50 C. and 100 C., a magnesium oxygen-containing compound and a magnesium salt. In some embodiments, the water is heated to a temperature of between approximately 70 C. and 90 C. The magnesium oxygen-containing compound may comprise one or more of magnesium oxide and magnesium hydroxide. The magnesium salt may comprise one or more of magnesium acetate, magnesium bromide, magnesium oxalate, magnesium thiosulfate, magnesium phosphate, magnesium nitrate, magnesium silicate, a magnesium chloride in any hydration state, anhydrous magnesium chloride, hexahydrate magnesium chloride, a magnesium sulfate in any hydration state, anhydrous magnesium sulfate, heptahydrate magnesium sulfate and magnesium carbonate.

A dry construction plaster composition made with at least stucco in an amount from about 25 to about 99 wt %; hydrated lime in an amount from about 0.5 to about 75 wt %; a phosphate-based lime bucking inhibitor in an amount from about 0.01 to about 1 wt %; and a setting reaction controlling agent, wherein the setting reaction controlling agent comprises a set accelerator, a set inhibitor, or any combination thereof is provided. Methods for preparing construction plaster slurries and pastes with reduced lime bucking and methods for finishing a substrate are also provided.