Abstract: The invention provides an apparatus for continuous thermal hydrolysis of cyanide ions and cyanide-containing ions contained in a liquid, comprising an elongated tubular reactor of a size selected to enable the liquid to be retained in the reactor for a predetermined reaction time, a conduit for supplying the liquid to the reactor, means for adding a base to the liquid prior to heating, and means, associated with the conduit, for instantaneously and uniformly heating the liquid to a preselected temperature. The apparatus preferably uses high pressure steam to heat the liquid and appears much less subject to fouling by scale.