Hergebruik van zinkbevattende afvalstromen uit de galvanische industrie. Eindrapport
report
Various wastes containing heavy metals are discharged by metal surface treatment companies. These include rinsing water, metal concentrates, pickling and degreasing bath liquids. These liquid wastes are converted into a solid, metal hydroxide sludge by most companies via their waste water purification systems. This sludge consists mainly of a mixture of various metals so that recycling is difficult and dumping in the C2-depot, which costs more than NLG 600 per ton, is the only waste disposal option. One way of increasing the recycling options is to use side stream purification of streams with the same metal so that a sludge containing one metal results (called mono-sludge). An investigation into side stream purification was carried out by TNO in 1991. This investigation showed for example that the recycling of zinc-containing sludges is pos sible, provided the quality of the sludge is improved. The emphasis was on zinc containing wastes as zinc coating is the most widely used galvanization process. The present investigation looks at the options for the improvement of the quality of the zinc-containing wastes on a laboratory and semi-practical scale. A certain quantity of ‘zinc mono-sludge’ was then re-used as the raw material at Union Minière (UM) in Zolder. This company prepares zinc oxide for example from zinc ashes and zinc slags.
Topics
TNO Identifier
253929
Publisher
TNO
Collation
59 p.
Place of publication
Apeldoorn