A raw meal for a cement clinker, a cement clinker made from that raw meal and a process for producing a cement clinker are provided. The clinker contains mainly the hydraulically activate alphaH-belite polymorph and calcium sulfoaluminate (ye'elimite or C.sub.4A.sub.3?), at the low firing temperature of 1050? C., using a combination of fluoride and boron oxide.

An apparatus for producing and analyzing sample materials may comprise a milling device for milling material components, a first metering device for metering a material component into the milling device, a second metering device for metering an activator liquid into the milled material component, a homogenization device for homogenizing the material components and the activator liquid to produce a sample material, a control device that is connected to the milling device and is configured to vary a parameter characteristic for milling intensity of the milling device so that particle size of the material components is altered, and a measuring device for determining a reactivity of the sample material. The present disclosure further concerns a process for producing and analyzing a plurality of sample materials. The process may involve varying at least one parameter characteristic for milling intensity for each sample material produced.

An apparatus for producing and analyzing sample materials may comprise a milling device for milling material components, a first metering device for metering a material component into the milling device, a second metering device for metering an activator liquid into the milled material component, a homogenization device for homogenizing the material components and the activator liquid to produce a sample material, a control device that is connected to the milling device and is configured to vary a parameter characteristic for milling intensity of the milling device so that particle size of the material components is altered, and a measuring device for determining a reactivity of the sample material. The present disclosure further concerns a process for producing and analyzing a plurality of sample materials. The process may involve varying at least one parameter characteristic for milling intensity for each sample material produced.

A belite-ye'elimite-ternesite cement clinker includes: ye'elimite: 20-50 wt. %; ternesite: 24-50 wt. %; belite: 10-35 wt. %; and free-calcium sulfate (f-C$): 2-10 wt. %. The composition of cement clinker includes an appropriate amount of ye'elimite minerals, ensuring fast early hydration and high early strength of the cement clinker. The cement clinker further includes a certain amount of free-calcium sulfate (f-C$), and is characterized by its good grindability, leading to decreased energy and mechanical losses essential for clinker grinding. This environmentally conscious and energy-efficient method aligns with the global objective of reducing carbon emissions.

A method can include reducing calcium sulfate to calcium sulfide, converting calcium sulfide to calcium oxide, optionally using the calcium oxide to form a product, optionally oxidizing sulfur dioxide to sulfuric acid, and optionally using the sulfuric acid in fertilizer production.

The invention provides novel carbonatable calcium silicate compositions and carbonatable calcium silicate phases that are made from widely available, low cost raw materials by a process suitable for large-scale production. The method of the invention is flexible in equipment and production requirements and is readily adaptable to manufacturing facilities of conventional cement. The invention offers an exceptional capability to permanently and safely sequesters CO.sub.2.

The invention provides novel carbonatable calcium silicate compositions and carbonatable calcium silicate phases that are made from widely available, low cost raw materials by a process suitable for large-scale production. The method of the invention is flexible in equipment and production requirements and is readily adaptable to manufacturing facilities of conventional cement. The invention offers an exceptional capability to permanently and safely sequesters CO.sub.2.

The invention provides a process for producing a cement clinker comprising: (i) mixing one or more starting materials providing each at least one or more of CaO, SiO.sub.2, AI.sub.2O.sub.3, and Fe.sub.2O.sub.3; and, optionally, SO.sub.3, to form a raw meal comprising CaO, SiO.sub.2, AI.sub.2O.sub.3, and Fe.sub.2O.sub.3; and, optionally, SO.sub.3, wherein the molar ratios among the aforementioned oxides is given by Formula I: S(CaO).sub.1(SiO.sub.2).sub.a(Al.sub.2O.sub.3).sub.b(Fe.sub.2O.sub.3).sub.c(SO.sub.3).sub.d, wherein: a is comprised from 0.05 to 1, b is comprised from 0.1 to 0.6, c is comprised from 0.001 to 0.25, and d is comprised from 0 to 0.3 and wherein at least 35% (p/p) of the starting materials of the raw meal have a critical microwaves absorbance temperature (Tc) comprised from 15 to 650 C. and a critical microwaves absorbance time (tc) comprised from 1 min to 1 h; (ii) heating the raw meal by irradiating with microwaves during 15 min to 3 h to reach a sintering temperature comprised from 300 to 950 C.; (iii) maintaining the microwave sintering temperature of step (ii) during 1 min to 3 h by further irradiating with microwaves; and (iv) cooling the clinker obtained in step (iii).

A method for stabilizing a wellbore includes introducing a hardening agent into the wellbore, mixing the hardening agent with a carrier fluid in the wellbore to produce a wellbore stabilizing fluid, and treating a wellbore wall of the wellbore by contacting the wellbore stabilizing fluid to a surface of the wellbore wall for at least 48 hours. A wellbore stabilizing fluid includes a hardening agent and a carrier fluid. The hardening agent is selected from one of 10 to 100 g/L of the calcium hydroxide nanocrystals, 5 to 99.9% by volume of tetraethyl orthosilicate (TEOS), and 10 to 50 g/L of zinc sulfate. A stabilized wellbore includes a wellbore having a wellbore wall treated with a wellbore stabilizing fluid comprising a hardening agent. The Young's modulus of the treated wellbore wall is at least 5% higher than a Young's modulus of a non-treated wellbore wall.

A method for stabilizing a wellbore includes introducing a hardening agent into the wellbore, mixing the hardening agent with a carrier fluid in the wellbore to produce a wellbore stabilizing fluid, and treating a wellbore wall of the wellbore by contacting the wellbore stabilizing fluid to a surface of the wellbore wall for at least 48 hours. A wellbore stabilizing fluid includes a hardening agent and a carrier fluid. The hardening agent is selected from one of 10 to 100 g/L of the calcium hydroxide nanocrystals, 5 to 99.9% by volume of tetraethyl orthosilicate (TEOS), and 10 to 50 g/L of zinc sulfate. A stabilized wellbore includes a wellbore having a wellbore wall treated with a wellbore stabilizing fluid comprising a hardening agent. The Young's modulus of the treated wellbore wall is at least 5% higher than a Young's modulus of a non-treated wellbore wall.