| 摘要 |
An additive is claimed for stabilisation of aq. sludges produced during metal-rich waste treatment and consisting of pptd. metal cpds. (esp. insoluble sulphides of hydroxides) in aq. phase, esp. those obtained from secondary ash from vitrification of domestic waste incineration waste gas cleaning residues. The additive comprises at least 50 wt.% oil-fired power station ash and balance alkaline (e.g. calcium)oxide or hydroxide.The treatment process involves: (a) furnace melting of the waste to be vitrified; (b) oxidn. of the furnace off-gas with air at ambient temp.; (c) dry quenching of the oxidised off-gas by dilution with air; (d) filtering; (e) scrubbing to neutralise the off-gas before discharge; (f) recovery of the metal salt-contg. secondary ash produced during steps (c) and (d); (g) formation of an aq. soln. from the secondary ash and pptn. of the metals as insoluble sulphides or hydroxides to obtain a sludge and an aq. saline liquor; (h) mixing the sludge with the above additive to stabilise the pptd. metals; (i) withdrawing the supernatant saline liquor; and (j) recovery, by decantation of the sludge, of the insoluble metal salts and the stabilised pptd. metals.
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