Abstract: A method of treating a spent dry film stripping and/or developing solution comprising the steps of adding about 0.01 to 15 grams of an aluminum source per liter of solution; adding about 0.05 to 25 grams of a metal precipitating agent per liter of solution; mixing the aluminum source, the metal precipitating agent and the solution with one another to form a mixture; adding an acid source to the mixture to lower the pH to less than about 6.5; and filtering the mixture to separate the metals and the photoresist from the remainder of the solution. The composition may also include 0 to 10 percent by weight of a dust-suppression agent, per liter of the solution, 0.1 to 10 grams of siliceous particulates per liter of spent stripper solution and/or an agent to enhance flocculation of the polymer precipitate.

Abstract: A powdered composition for treating spent dry film stripping and/or developing solutions comprising: 10 to 70 percent by weight of an aluminum source, such as aluminum sulfate, aluminum chloride; and 28 to 90 percent by weight of siliceous particulates, such as diatomaceous earth, sodium potassium aluminum silicate or expanded perlite. The powdered composition may also include 3 to 35 percent by weight of a metal precipitation agent, such as trimercapto-s-triazine, sodium dimethyldithiocarbamate, starch xanthate, sodium diethydithiocarbamate and thio red, to precipitate the metal from the spent solutions and/or 0 to 10 percent by weight of a dust-suppression agent such as water or propylene glycol. A method of using the disclosed compositions is also revealed in this application.