Burner for combustion or flame hydrolysis, and combustion furnace and process

A burner which prevents obstruction by combustion products has a circularly concentric multi-tube construction of three or more tubes, comprising a central tube which emits a liquid containing a chemical element that forms a solid oxide by combustion or flame hydrolysis, a first outer tube disposed concentrically outside the central tube for emitting a combustion-supporting gas and/or a non-combustible gas, a second outer tube disposed concentrically outside the first outer tube for emitting a combustion-supporting gas and/or a non-combustible gas, and optionally, a passage disposed outside the second outer tube for supplying a combustion-supporting gas and/or a non-combustible gas. The liquid emitted from the central tube is atomized and burned by the combustion-supporting gases and/or non-combustible gases supplied from the outer tubes and the optional passage disposed outside thereof. The flame thereby generated is covered by the combustion-supporting gases and/or non-combustible gases supplied from the outer tubes and the optional passage disposed outside thereof.