Patent ID: 7448231

Claim:
A process for manufacturing compounds based on one or more silicates of alkali metals, and/or of alkaline-earth metals, and/or of rare earths, said process involving a conversion reaction (1) in which halides of alkali metals and/or of rare earths and/or of alkaline-earth metals are converted into the corresponding sulfates in a first reactor, and a conversion reaction (2) in which the sulfates of alkali metals and/or of rare earths and/or of alkaline-earth metals are converted into the corresponding silicates in a second reactor, wherein the heat supply needed for converting the sulfates into the silicates is provided, at least in part, by a combustion reaction (3) using a submerged burner or a plurality of submerged burners, wherein sulfur oxides obtained during conversion reaction (2) are recovered and the sulfur oxides undergo a reaction (4′) to convert them into sulfuric acid, and wherein the sulfuric acid is used in reaction (1).