Abstract: A powdery composition based on silica for ceramic welding, in particular by projection, comprising from 10 to 90% of a phase of siliceous particles comprise at least 80% by weight of cristobalite and at most 15% by weight of tridymite, based on the total weight of the composition, from 90 to 10% by weight of conventional additives forming a binding phase, based on the total weight of the composition, said siliceous particles having a d50 comprised between 350 and 800 ?m, preferably between 400 and 500 ?m.

Abstract: A powdery composition based on silica for ceramic welding, in particular by projection, comprising from 10 to 90% of a phase of siliceous particles comprise at least 80% by weight of cristobalite and at most 15% by weight of tridymite, based on the total weight of the composition, from 90 to 10% by weight of conventional additives forming a binding phase, based on the total weight of the composition, said siliceous particles having a d50 comprised between 350 and 800 ?m, preferably between 400 and 500 ?m.

Abstract: A process of manufacturing a sulfoaluminate or ferroaluminate cement, and an apparatus for the manufacture. The cement is manufactured from a mixture containing CaCO3, Al3 and/or Al(OH)3, CaSO4, SiO2 and/or a product containing silica or silicates such as clay, these compounds being present in the anhydrous or hydrated form. In this process, the mixture is treated up to clinkering by movement in a center of a kiln, in a sheet with approximately constant thickness, at approximately constant speed, along a treatment path having a positive temperature gradient, and for a treatment time during which the mixture remains below its melting temperature. The mixture is clinkered to produce a clinkered mixture that is cooled upon exit from the treatment path.

Abstract: Manufacturing process of a sulfoaluminate or ferroaluminate cement, cement obtained by this process, and installation for implementation. The invention concerns a manufacturing process of cement (1) from a mixture (2) containing CaCO3, Al2O3 and/or Al(OH)3, CaSO4, SiO2 and/or a product containing silica or silicates such as clay, these compounds being present in the anhydrous or hydrated form, individually or in combination.