Process for recovery of silver from hardening photoprocessing solutions
AssigneeEastman Kodak Company
InventorsJames R. Kulp, Charles S. Christ, Jr., Jay E. Mathewson
Life of this patent
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Abstract
There is provided a method for removing silver from photoprocessing solutions containing hardening agents which comprises: a) adding a chelating agent to the photoprocessing solution in an amount sufficient to inhibit the precipitation of the high valent cations of the hardening agents; b) adding a base to adjust the pH of the photoprocessing solution to a value above 5.5; and c) adding a chemical precipitant for the silver contained in the photoprocessing solution; and optionally adding as a final component a flocculating agent which causes the precipitate to grow in size.
Claims14
A process for precipitating silver from solutions containing silver and high valent cationic hardening agents which comprises adding 0.15 to 1.5 moles of chelating compound per mole of cationic hardening agent to a solution containing silver and high valent cationic hardening agents at a pH below 5.5 to complex the high valent cations selected from the group consisting of Al.sup.+3 and Zr.sup.+4, adjusting the pH above 5.5 with the addition of base and precipitating silver by the addition of a chemical precipitant for silver.
Dependencies are inferred from the claim text.