Methods to prepare a well cementing slurry include coating particles comprising an expanding agent with a component selected from the group consisting of a phenolic resin, a silica, a calcination product of a polysiloxane oil, and a combination thereof; and combining the coated particles with mix water and hydraulic cement to form a cement slurry for cementing a well.

The invention relates to a process for preparing silica-coated particles of an inorganic expanding agent, the silica-coated particles and their use. The silica-coated particles show a delayed release of the expanding agent particularly in alkaline medium and at elevated temperatures. They are therefore useful in the oil and construction industry.

The invention relates to a process for preparing silica-coated particles of an inorganic expanding agent, the silica-coated particles and their use. The silica-coated particles show a delayed release of the expanding agent particularly in alkaline medium and at elevated temperatures. They are therefore useful in the oil and construction industry.

Cementitious compositions and methods for preparing and using the cementitious compositions to yield hardened concrete. The cementitious compositions yield hardened concrete having reduced or attenuated water vapor emission and lower internal relative humidity (IRH). Cementitious compositions are characterized by the property of rapid surface drying while maintaining good workability, particularly when using porous lightweight aggregates that absorb substantial amounts of water. Methods of decreasing water availability and increasing surface drying of concrete, including lightweight concrete, are provided. A water soluble ionic salt may be used to sequester water within the pores and capillaries of the cement paste and/or porous lightweight aggreate by modifying the colligative propertie of pore water. The salt may be added directly to concrete or the concrete mix water, or, alternatively, aggregates may be infused with a water-salt solution to provide treated porous aggregates having improved water saturation and water retention.

Cementitious compositions and methods for preparing and using the cementitious compositions to yield hardened concrete. The cementitious compositions yield hardened concrete having reduced or attenuated water vapor emission and lower internal relative humidity (IRH). Cementitious compositions are characterized by the property of rapid surface drying while maintaining good workability, particularly when using porous lightweight aggregates that absorb substantial amounts of water. Methods of decreasing water availability and increasing surface drying of concrete, including lightweight concrete, are provided. A water soluble ionic salt may be used to sequester water within the pores and capillaries of the cement paste and/or porous lightweight aggreate by modifying the colligative propertie of pore water. The salt may be added directly to concrete or the concrete mix water, or, alternatively, aggregates may be infused with a water-salt solution to provide treated porous aggregates having improved water saturation and water retention.

Dark colored roofing granules include an inert base particle coated with a composition including a metal silicate, a non-clay latent heat reactant, and a dark colored but solar reflective pigment.

Dark colored roofing granules include an inert base particle coated with a composition including a metal silicate, a non-clay latent heat reactant, and a dark colored but solar reflective pigment.

The present disclosure concerns expandable silica particles having a coating comprising talc powder and kaolin powder provided on the outer surface of the expandable silica particle and expandable and expanded silica particles comprising silica fume and/or ultrafine quartz silica sand beneath the surface of the particles. Methods for producing expandable and expanded silica particles are disclosed, including a method using a vibration plate and a furnace having a vibration plate for carrying out that method. The expanded silica particles have high compressive strength, substantially uniform cell size and distribution, low water absorption, and low porosity on the outer surface. They are useful as a filler in matrix materials, like concrete or epoxy, as insulation material with various binder materials, and as water filtration medium.

The present disclosure concerns expandable silica particles having a coating comprising talc powder and kaolin powder provided on the outer surface of the expandable silica particle and expandable and expanded silica particles comprising silica fume and/or ultrafine quartz silica sand beneath the surface of the particles. Methods for producing expandable and expanded silica particles are disclosed, including a method using a vibration plate and a furnace having a vibration plate for carrying out that method. The expanded silica particles have high compressive strength, substantially uniform cell size and distribution, low water absorption, and low porosity on the outer surface. They are useful as a filler in matrix materials, like concrete or epoxy, as insulation material with various binder materials, and as water filtration medium.

A treatment method for coal fly ash, and in particular sodic fly ash, comprises 1) contacting the coal fly ash with anhydrite, and 2) contacting the coal fly ash in the presence of water with at least one additive. The material obtained from the contacting steps (1) and (2) may be dried. The steps (1) and (2) may be carried simultaneously or sequentially. The additive may comprise at least one component selected from the group consisting of strontium-containing compounds, barium-containing compounds, dolomite, a dolomite derivative such as calcined or hydrated dolomite, water-soluble sources of silicate such as sodium or potassium silicate, iron-containing compounds, and any combinations thereof. A particularly preferred additive comprises sodium silicate. The method may be effective in reducing the sodium content in the fly ash (Na.sub.2O), reducing the alkalinity of the fly ash, and/or stabilizing at least one heavy metal such as selenium and/or arsenic to reduce their leachability.