The invention relates to a method and a system for producing cement clinker from raw cement mixture, wherein one part of the raw cement mixture is preheated in a calciner preheater, and the other part of the raw cement mixture is preheated in an oven preheater, the preheated raw cement mixture is pre-calcined in a calciner which is operated according to the oxyfuel method, the pre-calcined raw cement mixture is fired in an oven, the fired raw cement mixture is cooled in a cooler, the calciner preheater is operated using exhaust gases of the calciner, the oven preheater is operated using exhaust gases of the oven, an entrained flow reactor is used as the calciner, a part of the calciner exhaust gas being recirculated to the calciner after being used in the calciner preheater, and the oven exhaust gas undergoes a post-combustion CO.sub.2 separation.

The present invention relates to the field of oil and natural gas well cementation engineering, in particular to a foam stabilizer composition, foamed cement slurry and an additive composition thereof. The foam stabilizer composition comprises C6-C20 alkyl amido alkyl amine oxide, C6-C20 alkyl amido alkyl betaine, and triterpenoid saponin compound. The foam stabilizer composition provided in the present invention is helpful for forming foamed cement slurry that has high foam stability, and the foam stabilizer composition can work with other active components in the foamed slurry additive composition provided in the present invention to enable the foamed cement slurry that contains the additive composition to obtain low density, high foam stability, low permeability, and high compressive strength, which is especially applicable to well cementing operation in an oil and natural gas exploration and development process.

A hydraulic well cementing composition is disclosed. The well cementing composition contains a hydraulic cement and a fluid loss additive. The fluid loss additive is the polymerization reaction product of a two vinylamide monomers, wherein the polymerization reaction is conducted in the presence of a molecular weight control agent. One of the vinylamide monomers includes a sulfonic acid function, the second vinylamide monomer does not include a sulfonic acid function. The fluid loss additive controls fluid loss at temperatures up to 350 F.

A method of producing refractory brick includes heating a spent Claus catalyst, reducing a particle size of the catalyst, dry mixing the catalyst with cement to form a dry mixture, adding water to the dry mixture to form a castable mixture, casting the castable mixture in a mold, curing the mold, and drying the mold to form the refractory brick.

A method of producing refractory brick includes heating a spent Claus catalyst, reducing a particle size of the catalyst, dry mixing the catalyst with cement to form a dry mixture, adding water to the dry mixture to form a castable mixture, casting the castable mixture in a mold, curing the mold, and drying the mold to form the refractory brick.

The invention provides compositions and methods directed to carbonation of a cement mix during mixing. The carbonation may be controlled by one or more feedback mechanisms to adjust carbon dioxide delivery based on one or more characteristics of the mix or other aspects of the mixing operation.

Environmentally friendly concrete compositions and methods thereof are disclosed. For example, a method for producing an environmentally friendly concrete installation can include mixing cement, one or more locally sourced pozzolans, and one or more locally sourced aggregates to produce a dry concrete mixture. At least one fine aggregate or coarse aggregate of the dry concrete mixture is a locally sourced aggregate of the one-or-more locally sourced aggregates for a reduced carbon footprint. The method can include hydrating the dry concrete mixture with water to make a pourable concrete mixture. The method can include pouring the pourable concrete mixture into a formwork to produce a poured concrete form. The method can include allowing the poured concrete form to cure to produce the concrete installation. The reduced carbon footprint of the concrete installation is relative to that of a similar concrete installation produced without the one-or-more locally sourced pozzolans or aggregates.

A method of manufacturing an activated pozzolan composition includes: (i) grinding a natural pozzolan, alone or with another mineral component that is not cement clinker, to form a finely ground pozzolan component having a first d90 in a range of about 10 m to about 45 m and a first d10 less than about 5 m; and (ii) blending, without intergrinding, the finely ground pozzolan component with a coarse particulate mineral component comprised of coarse mineral particles not interground with the fine interground particulate component, the coarse particulate component having a second d90 greater than the first d90 and a second d10 greater than the first d10. The natural pozzolan can be one or more of natural pozzolanic deposits, volcanic ash, metakaolin, shale dust, calcined clay, trass, and pumice.

A method for manufacturing calcined clays comprising extracting and mixing raw clays; dosing a reducing agent to the mixed raw clays and homogenizing the resulting mixture; reducing the particle size of the mixture to less than 10 mm; heating the mixture in a flash dryer or flash calciner until the mixture has between 0% and 5% moisture; calcining the dried mixture from 600 to 900 C., maintaining an oxygen concentration between 1 and 5%; and cooling the calcined clay from 900 C. to 120 C., and uses of such calcined clay resulting from the claimed method in cement and/or a cementitious material for preparing concrete.

Disclosed herein is a concrete article comprising: a plurality of pores having an average pore diameter of less than 1 micron as measured using mercury intrusion porosimetry (MIP) with a pressure of less than 440 MPa and overall porosity of less than 15% measured using helium porosimetry, wherein the concrete article exhibits a gas permeability of 10.sup.17 to 10.sup.22 m2 as measured under steady-state conditions (with an upstream chamber pressure of 0.31 MPa and a downstream chamber pressure of less than 5 Pa) and is configured to substantially prevent a gas leak. Also disclosed are methods of making the same articles.