Abstract: The disclosure relates to a method for producing hydrogen gas and/or magnetite comprising the steps of reacting a wüstite-containing material, such as steel slags, with H2O at a temperature ranging from 150° C. to 500° C., cooling down the gaseous reaction product to separate hydrogen gas from water steam and collecting hydrogen gas, and recovering magnetite from the solid reaction product.

Abstract: The application relates to a method for preparing magnetite, comprising steps of: a) reaction at a temperature of 100° to 500° C. of a material containing wüstite with water, in order to obtain a solid comprising magnetite, and then b) recovery of the magnetite in the form of particles wherein more than 25% by weight are of nanometric size.

Abstract: The application relates to a method for preparing magnetite, comprising steps of: a) reaction at a temperature of 100° to 500° C. of a material containing wüstite with water, in order to obtain a solid comprising magnetite, and then b) recovery of the magnetite in the form of particles wherein more than 25% by weight are of nanometric size.

Abstract: The disclosure relates to a method for producing hydrogen gas and/or magnetite comprising the steps of reacting a wüstite-containing material, such as steel slags, with H2O at a temperature ranging from 150° C. to 500° C., cooling down the gaseous reaction product to separate hydrogen gas from water steam and collecting hydrogen gas, and recovering magnetite from the solid reaction product.

Abstract: The disclosure relates to a method for producing hydrogen gas comprising the steps of reacting steel slags with H2O at a temperature ranging from 150° C. to 500° C., cooling down the reaction product of step (a) to separate hydrogen gas from water steam and collecting hydrogen gas.

Abstract: In a process to design high temperature cement sluries, the temperature stable phases (anorthite, wairakite) are selected; aluminum modifiers and silica oxides are added to the dry cement so that the elemental composition of the blend corresponds to the phases selected; the control of the particle size distribution and the relative amount of those minerals allow their addition at high concentration while leaving the slurry easily mixable and pumpable; and the kinetics of the targeted phases formation is then controlled by adjusting the crystallinity and the particles sizes of the different solids.

Abstract: A method of designing a cement composition comprises determination of the temperature to which the composition will be exposed in situ; determination of a stable, thermodynamic equilibrium composition of a CaO—Al2O3—SiO2—H2O (CASH) mineral system in the [xonotlite/wollastonite]-grossulaire-anorthite or grossulaire-anorthite-quartz triangles of the Si—Ca—Al phase diagram with a possible contribution of iron and/or magnesium, analogous to the cement when set, at the determined temperature; determining proportions of cement and mineral oxides required to provide a mixture having the determined composition; and defining a series of particulate materials of predetermined particle sizes and densities, comprising cement and mineral oxides in the determined proportions.

Abstract: A method of designing a cement composition comprises determination of the temperature to which the composition will be exposed in situ; determination of a stable, thermodynamic equilibrium composition of a CaO—Al2O3—SiO2—H2O (CASH) mineral system in the [xonotlite/wollastonite]-grossulaire-anorthite or grossulaire-anorthite-quartz triangles of the Si—Ca—Al phase diagram with a possible contribution of iron and/or magnesium, analogous to the cement when set, at the determined temperature; determining proportions of cement and mineral oxides required to provide a mixture having the determined composition; and defining a series of particulate materials of predetermined particle sizes and densities, comprising cement and mineral oxides in the determined proportions.

Abstract: In a process to design high temperature cement sluries, the temperature stable phases (anorthite, wairakite) are selected; aluminum modifiers and silica oxides are added to the dry cement so that the elemental composition of the blend corresponds to the phases selected; the control of the particle size distribution and the relative amount of those minerals allow their addition at high concentration while leaving the slurry easily mixable and pumpable; and the kinetics of the targeted phases formation is then controlled by adjusting the crystallinity and the particles sizes of the different solids.

Abstract: The present invention concerns cementing compositions for an oil well or the like, based on a Portland cement, silica and alumina, wherein the mineralogical composition of the cement matrix is included in the Si—Ca—Al triangle in one of the margarite-haüyne-[epidote/pumpellyite], haüyne-prehnite-[epidote/pumpellyite] and haüyne-prehnite-pectolite composition triangles. More particularly, the cementing compositions of the invention are suitable for cementing wells subjected to high temperatures and to chemical attack by brines, and are more suitable when the brine—or a saline formulation close to that of the brine—is used as the mixing water.

Abstract: The present invention concerns cementing compositions for an oil well or the like, based on a Portland cement, silica and alumina, wherein the mineralogical composition of the cement matrix is included in the Si—Ca—Al triangle in one of the margarite-haüyne-[epidote/pumpellyite], haüyne-prehnite-[epidote/pumpellyite] and haüyne-prehnite-pectolite composition triangles. More particularly, the cementing compositions of the invention are suitable for cementing wells subjected to high temperatures and to chemical attack by brines, and are more suitable when the brine—or a saline formulation close to that of the brine—is used as the mixing water.