de - Beste verfügbare Techniken (BVT) - Umweltbundesamt

Chapter 2
2.5.16 Processes involving heavy metals
[1, Hunger, 2003, 6, Ullmann, 2001, 16, Winnacker and Kuechler, 1982, 51, UBA, 2004],
*018A,I*, *015D,I,O,B*
Heavy metals are involved in chemical synthesis:
• if the feedstock or product contains heavy metals
• if the heavy metals are used as auxiliaries (e.g. catalysts, redox partners).
Table 2.16 gives an impression of the type of processes involving heavy metals.
1:1 or 1:2
complexes to form
azo dyes
Metal Solvents Agent
Metallisation to form chelated metals
Chromium
Nickel
Cobalt
Copper
Oxidations Manganese
Chromium
Molybdenum
Water
Dilute NaOH
Formic acid
Formamide
Unit processes
Cr2O3
CrCl3*6H2O
K2Cr2O7*2H2O/glucose
Cr formate
NaKCr salicylate
CoSO4*7H2O/NaNO2
CuSO4*5H2O
CuCl2
MnO2
CrO3
Reductions Zinc
Copper
Mercury
Tin
Metal, metal chlorides
Hydrogenation Nickel
Catalysts
Raney nickel
Nickel
Copper
Cobalt
Manganese
Palladium
Platinum
Ruthenium
Bismuth
Titanium
Zirconium
Table 2.16: Typical processes involving heavy metals
Environmental issues
Metals, metal oxides,
chlorides or acetates,
carbonyls
Table 2.17 gives some example data of the waste streams from processes involving heavy
metals.
Heavy metals are not degradable but are adsorbed to the sludge or passed through the WWTP.
Heavy metal loadings in sewage sludge cause problems for disposal and, therefore, the
increased costs of disposal or treatment have to be taken into account.
Catalysts containing precious metals are to be sent advantageously to recycling companies.
66 Dezember 2005 OFC_BREF