EDTA disodium salt → Ethylenediaminetetraacetic Acid

Participants

Reaction Steps

A seasoned Kodak 885 hardened fixer was treated in the silver recovery unit 300 shown in FIG. 3, which incorporates a silver precipitating unit 80 according to U.S. Pat. No. 5,437,492 and described above. A continuous stream of untreated Kodak 855 hardened fixer at a flow rate of 100 mls/minute is provided in line 320. A solution of 7.5 g/l disodium EDTA dihydrate and 35 g/l sodium carbonate in storage vessel 310 is drawn off via line 311 by pump 312. The solution is then pumped to line 320 via line 313 and injected at a rate of 100 mls per minute through tee 315 into a seasoned Kodak 885 hardened fixer solution with a pH of about 4.8, flowing at a rate of 100 mls per minute in line 320. The resulting solution is then mixed within a tubular reactor 316. The solution is then returned to silver recovery unit 80 according to U.S. Pat. No. 5,437,792, which employs TMT as a silver precipitating agent and a flocculant to agglomerate the TMT-silver precipitate, as described above.

Provenance & Evidence