The present disclosure relates generally to building materials, such as building boards, having improved strength and reduced shrinkage. More particularly, the present disclosure provides building compositions comprising Struvite-K (KMgPO.sub.4.6H.sub.2O), Syngenite (K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O), and one or more silicate additives suitable for use in building materials.

The present invention disclosed a cross-linked plugging agent stimulated by high density brine which comprises main agent: 10 wt %-90 wt %, gelling agent: 0.5 wt %-9 wt % and pure water; wherein the main agent is selected from the group consisting of a Dipotassium phosphate (K.sub.2HPO.sub.4), a Tripotassium phosphate (K.sub.3PO.sub.4) and a Potassium pyrophosphate (K.sub.4P.sub.2O.sub.7), a Potassium Dihydrogen Phosphate (KH.sub.2PO.sub.4), a Sodium dihydrogen phosphate (NaH.sub.2PO.sub.4); the gelling agent is selected from the group consisting of a Xanthan gum and a kappa carrageenan. The gelling time is controlled within 0.5-12 h under an experiment temperature of 90 C.-160 C. The final gelling strength is controlled within D-H. The density is controlled within 1.0-1.55 g/cm.sup.3. The plugging agent is able to be applied in well completion and workover under high temperature, high pressure, multi-pressure series of strata oil and gas environment when temporary blockage and leak proof is required, protection of reservoir near perforations and water plugging.

The present invention disclosed a cross-linked plugging agent stimulated by high density brine which comprises main agent: 10 wt %-90 wt %, gelling agent: 0.5 wt %-9 wt % and pure water; wherein the main agent is selected from the group consisting of a Dipotassium phosphate (K.sub.2HPO.sub.4), a Tripotassium phosphate (K.sub.3PO.sub.4) and a Potassium pyrophosphate (K.sub.4P.sub.2O.sub.7), a Potassium Dihydrogen Phosphate (KH.sub.2PO.sub.4), a Sodium dihydrogen phosphate (NaH.sub.2PO.sub.4); the gelling agent is selected from the group consisting of a Xanthan gum and a kappa carrageenan. The gelling time is controlled within 0.5-12 h under an experiment temperature of 90 C.-160 C. The final gelling strength is controlled within D-H. The density is controlled within 1.0-1.55 g/cm.sup.3. The plugging agent is able to be applied in well completion and workover under high temperature, high pressure, multi-pressure series of strata oil and gas environment when temporary blockage and leak proof is required, protection of reservoir near perforations and water plugging.

A construction method for reinforcing a loess embankment by combining microbial mineralization with phosphogypsum. The method includes: (1) placing Bacillus pasteurii in a culture medium to prepare a microbial solution, and mixing urea, calcium chloride and water to prepare a cementing solution; (2) mixing a mixture, the microbial solution and water well, and adding the cementing solution and water to prepare an improving mixture; and (3) leveling and compacting an original ground; laying a geomembrane, the improving mixture and a geogrid; laying a last geomembrane on the top of the embankment after the embankment is laid, and then laying a roadbed. The method meets the improvement and construction requirements of loess embankments of high-grade highways, and reduces the stock of phosphogypsum, thereby reducing the occupation of cultivated land. The microbial improvement of the phosphogypsum achieves the immobilization of harmful elements, thereby reducing environmental pollution.

What are described are a process for producing an insulating product for the refractory industry or an insulating material as intermediate for production of such a product, and a corresponding insulating material/insulating product. Likewise described are the use of a matrix encapsulation process in the production of an insulating product for the refractory industry and a corresponding insulating product and/or an insulating material as intermediate for production of such a product.

What are described are a process for producing an insulating product for the refractory industry or an insulating material as intermediate for production of such a product, and a corresponding insulating material/insulating product. Likewise described are the use of a matrix encapsulation process in the production of an insulating product for the refractory industry and a corresponding insulating product and/or an insulating material as intermediate for production of such a product.

A method for making a porous, chemically bonded ceramic shaped article comprises i) providing a precursor powder mixture comprising polymer particles and a ceramic self-setting cementitious powder; ii) preparing a shaped article from a paste comprising the precursor powder mixture and an aqueous liquid; and iii) immersing the shaped article in an immersing liquid in which the polymer particles are soluble, for a period of time of from about 10 minutes to about two weeks to dissolve the polymer particles in the immersing liquid, thereby creating pores in the shaped article. A porous, chemically bonded ceramic shaped article having interconnected pores, a total porosity of at least about 50%, and a macroporosity of at least about 30% can be formed by such methods.

A method for making a porous, chemically bonded ceramic shaped article comprises i) providing a precursor powder mixture comprising polymer particles and a ceramic self-setting cementitious powder; ii) preparing a shaped article from a paste comprising the precursor powder mixture and an aqueous liquid; and iii) immersing the shaped article in an immersing liquid in which the polymer particles are soluble, for a period of time of from about 10 minutes to about two weeks to dissolve the polymer particles in the immersing liquid, thereby creating pores in the shaped article. A porous, chemically bonded ceramic shaped article having interconnected pores, a total porosity of at least about 50%, and a macroporosity of at least about 30% can be formed by such methods.

The present disclosure relates to a cementious composition (e.g. for mounting a strain gauge within a gas turbine engine) comprising: part A comprising an acidic solution of a metal salt; part B comprising silica and one or more metal oxides; and part C comprising colloidal silica and/or a silicate solution. Part A may comprise an acidic aluminium phosphate solution. Part B may comprise one or more or all of titanium oxide, chromium oxide, alumina and barium oxide

A refractory composition including refractory aggregate, one or more matrix components, and silicate-coated set accelerator particles. The silicate-coated set accelerator particles can include one more of silicate-coated calcium hydroxide, magnesium hydroxide, calcium chloride, calcium carbonate, magnesium carbonate and calcium sulfate. Suitable silicate coatings include sodium silicate, potassium silicate, lithium silicate and mixtures thereof. A method of recovering an aged refractory composition, a settable composition and a method of manufacturing silicate-coated calcium hydroxide particles are also provided.