Liquid purification or separation – Processes – Ion exchange or selective sorption
Patent
1985-06-28
1987-11-24
Cintins, Ivars
Liquid purification or separation
Processes
Ion exchange or selective sorption
210684, 423371, 521 26, C02F 142
Patent
active
047088044
ABSTRACT:
A process is provided for removing cyanide from a dilute cyanide solution. The solution is passed through a weak base anion exchange resin to absorb cyanide complexes. The resin is eluted with a weakly basic Ca(OH).sub.2 solution, to produce a cyanide-rich eluate. Elution is accomplished by recycling the eluting fluid past a bed of solid Ca(OH).sub.2, to maintain the eluting fluid in Ca(OH).sub.2 saturation. Recycling in this manner produces an eluate with relatively high cyanide concentration using economical reagents. The eluate is subjected to an acidification/volatilization process including acidification, preferably with H.sub.2 SO.sub.4, heating by introduction of steam and removal of volatilized HCN by an air sparge. The HCN-rich off-gas and slats produced therefrom may be recycled in the process. The cyanide-depleted waste streams may be disposed of in, for example, tailings ponds.
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Cintins Ivars
Resource Technology Associates
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