Abstract: A process for separating from each other heavy metals and an ash agglomerate in the form of individual granules or pellets having substrate properties. Environmentally acceptable metal chlorides and, if appropriate, fillers are mixed with the ash in a first step and the resulting mixture is subjected to agglomeration and/or compaction or conversion into particles. The agglomerate obtained in this way is heated to a temperature above the boiling point of the heavy metal chlorides. The resulting gaseous heavy metal chlorides are separated from the agglomerate. The remaining porous ash agglomerate is depleted in heavy metals and can be used as fertilizer in an original, milled or regranulated particle form.