Partial combustion of hydrogen sulphide

A method of forming sulphur vapor by partial oxidation of hydrogen sulphide, comprising operating a burner to establish a flame in a furnace in or into which the burner fires, supplying to the flame from a first region of the mouth of the burner at least one flow of a first combustible gas comprising hydrogen sulphide and ammonia, causing at least one, second flow of a first oxidizing gas consisting of oxygen gas or oxygen-enriched air to issue from the mouth of the burner and mix in the flame with the first combustible gas, supplying to the flame from a second region of the mouth of the burner surrounding and spaced apart from said first region at least one, third flow of a second combustible gas consisting of hydrogen sulphide, wherein the mass flow rate of said first combustible gas and the mass flow rate of said second combustible gas to said burner are controlled independently of one another, causing at least one, fourth flow of a second oxidizing gas consisting of oxygen gas or oxygen-enriched air to issue from a region or regions of the mouth of the burner surrounded by said second region and mix in the flame with the second combustible gas, causing at least one, fifth, outermost flow of a third oxidizing gas to mix in the flame with the second combustible gas, and withdrawing from the furnace a resultant gas mixture including sulphur vapor, water vapor, sulphur dioxide, hydrogen and residual hydrogen sulphide.