Vitrification of fly ash

In a vertical flash smelter the material that shall be vitrified is introduced into a stream of plasma heated gas.

The material melts and accumulates at the bottom of the reactor and is continuously tapped through a siphon type tapping device. In a hot cyclone remaining slag droplets are separated from the gas.

Energy to the process is supplied by a plasma generator and by partial combustion of coal in the feed material.

By adjustment of the oxygen content in the plasma gas, selective reduction and volatilization of, for example, zinc and lead can be achieved. The content of these materials in the produced slag can be reduced to very low levels.

The process is especially suitable for melting and vitrification of fly ash from waste incinerators.

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