Process for removing heavy metals from sludge liquors, sludges and waters containing cyanides or modified isonitriles

摘要

The process presented for removing heavy metals from sludges, sludge liquors and waters is a process which exploits the strong complexing properties of the cyanide ion and its derivatives. These ligands are not only able to complex dissolved metals but are also able to open up included metals and to dissolve metal bonds. A consequential circulation and easy controllability of the process ensure a low cyanide consumption or use of isonitrile polymer. Cyanide ions carried over are quantitatively and environmentally acceptably destroyed with Perhydrol (hydrogen peroxide solution) or returned to the process. Addition of small amounts of citrates, tartrates or ammonia can optimise the efficiency of this process for individual metals. By means of the process presented here, not only can heavy metals introduced by humans into the environment be recovered, but also heavy metals already existing in the environment (geogenic) can be extracted (e.g. from sea water).