Disclosed are a method for separately preparing light magnesium oxide and calcium oxide by using dolomite and an application thereof in preparation of a calcium-magnesium composite expanding agent. In the method for preparing light magnesium oxide and calcium oxide, based on the difference in decomposition temperature between magnesium carbonate and calcium carbonate during the calcination and decomposition of dolomite and the difference in the weight of the materials after decomposition, the effective separation of magnesium oxide and calcium oxide is realized by a one-step method, thus separately preparing light magnesium oxide and light calcium oxide. The calcium-magnesium composite expanding agent is prepared by using the foregoing light magnesium oxide and calcium oxide. On the one hand, the present invention solves the problem of the limited origin of the light magnesium oxide raw material of the magnesium expanding component in the calcium-magnesium composite expanding agent.

Various aspects disclosed relate to hybrid nanoparticles embedded in non-magnetic microparticles. These materials can be used to directionally orient and impart an ordered structure to a variety of materials.

Various aspects disclosed relate to hybrid nanoparticles embedded in non-magnetic microparticles. These materials can be used to directionally orient and impart an ordered structure to a variety of materials.

A method of cementing a wellbore comprises injecting into the wellbore a cement slurry comprising an aqueous carrier, a swellable nanoclay, and a solid delayed releasing divalent inorganic salt comprising calcined magnesium oxide, calcined calcium oxide, calcium magnesium polyphosphate, a borate, a nitride, a silicate, an agent having a cation of Ba.sup.2+, Sr.sup.2+, Fe.sup.2+, Ni.sup.2+, or a combination comprising at least one of the foregoing; and allowing the cement slurry to set.

A method of cementing a wellbore comprises injecting into the wellbore a cement slurry comprising an aqueous carrier, a swellable nanoclay, and a solid delayed releasing divalent inorganic salt comprising calcined magnesium oxide, calcined calcium oxide, calcium magnesium polyphosphate, a borate, a nitride, a silicate, an agent having a cation of Ba.sup.2+, Sr.sup.2+, Fe.sup.2+, Ni.sup.2+, or a combination comprising at least one of the foregoing; and allowing the cement slurry to set.

Methods for using cement compositions in subterranean formations are provided. In some embodiments, the methods comprise introducing a first treatment fluid comprising a first base fluid and a metal oxide into a wellbore penetrating at least a portion of a subterranean formation; introducing a spacer fluid into the wellbore that separates the first treatment fluid from at least a second treatment fluid; introducing the second treatment fluid into the wellbore, wherein the second treatment fluid comprises a second base fluid and a soluble salt; allowing the first treatment fluid to contact the second treatment fluid to form a cement mixture; and allowing the cement mixture to at least partially set.

Methods for using cement compositions in subterranean formations are provided. In some embodiments, the methods comprise introducing a first treatment fluid comprising a first base fluid and a metal oxide into a wellbore penetrating at least a portion of a subterranean formation; introducing a spacer fluid into the wellbore that separates the first treatment fluid from at least a second treatment fluid; introducing the second treatment fluid into the wellbore, wherein the second treatment fluid comprises a second base fluid and a soluble salt; allowing the first treatment fluid to contact the second treatment fluid to form a cement mixture; and allowing the cement mixture to at least partially set.

A method of using a gas control additive to provide gas migration control in a wellbore includes the steps of mixing the gas control additive with a cement to form a cement slurry, where the gas control additive includes a semi-permeable membrane and a scrubbing agent, such that the semi-permeable membrane forms a shell around a core such that the scrubbing agent is in the core, introducing the cement slurry to the wellbore, and reacting the scrubbing agent with an antagonistic gas to produce a helper byproduct, where the antagonistic gas migrates from a hydrocarbon-bearing formation into the wellbore and permeates through the semi-permeable membrane to the core of the gas control additive.

A method of using a gas control additive to provide gas migration control in a wellbore includes the steps of mixing the gas control additive with a cement to form a cement slurry, where the gas control additive includes a semi-permeable membrane and a scrubbing agent, such that the semi-permeable membrane forms a shell around a core such that the scrubbing agent is in the core, introducing the cement slurry to the wellbore, and reacting the scrubbing agent with an antagonistic gas to produce a helper byproduct, where the antagonistic gas migrates from a hydrocarbon-bearing formation into the wellbore and permeates through the semi-permeable membrane to the core of the gas control additive.

The present invention discloses an artificial stone slab, wherein the raw materials are mixed, pressed, and solidified, and the raw material comprises a main material and an auxiliary material. The main material, according to the total weight ratio of raw materials, comprises from about 20% to about 85% of particles containing hydroxide or metal oxide, from about 0% to about 50% of natural quartz, and from about 5% to about 25% of resin. The auxiliary material comprises a coupling agent and a curing agent, wherein the weight ratio of the coupling agent to the resin is from about 0.6:100 to about 2:100, and the weight ratio of the curing agent to the resin is from about 0.8:100 to about 1.2:100. The present invention also provides methods for manufacturing the aforesaid artificial stone slab. The present invention replaces natural quartz particles with particles containing hydroxide or metal oxide and ensures that the performance of the slab is up to standard, that the quality is more stable and easier to control, the decorative results are better, and finally, the mining of natural quartz is reduced by 10 times, achieving the objectives of greater environmental protection and lower costs. The resulting slab provides stable performance with good decorative results and thus saves resources and is conducive to environmental protection.