Tri:mercapto-triazine recovery from metal tri:mercapto-triazine ppte. - by adding chelating agent, precipitating metal complex with organic onium cpd. and pref. recovering metal from ppte. by pptn. rom organic solvent soln.

摘要

Recovery of trimercaptotriazine (I) from metal trimercaptotriazine pptes. (II) comprises : (a) treating (II) with a chelating agent (III), in aq. soln. which forms a metal complex with stability constant lower than the solubility prod. of (II); (b) pptg. the complexed metal ions with a mono- or poly-alkyl- or -aryl-substd. ammonium, phosphonium or arsonium cpd.; and (c) sepg. (I) from the mother liquor in known manner. Pref. (V) is dissolved in an organic solvent (VI) and reacted with a metal salt, which is soluble in (VI), to convert it to a metal salt insol. in (VI). USE/ADVANTAGE - The process is useful for recovering (I) used as pptn. reagent for non-ferrous metals and metals which can be pptd. from aq. soln. with sulphides, e.g. in waste liquor treatment, recovery of metals from treatment baths and demetallisation of flue gas scrubbing solns.. Normally only (II) contg. fairly amts. of nobile metals are worked and (I) is lost, since it is oxidised in the melt metallurgical process used, whilst other (II) can be dumped safely, since they are very stable and insol. even in conc. H2SO4. Recovery of both (I) and the metal avoids this waste. Pptn. of the complex salts (V) in quantitative and (I) losses are under 1 wt.% (V) are usually very pure and can be worked up directly or used for chemical processes.