Recovery process for electroless plating baths

Patent · Tue May 12 00:00:00 EDT 1992

OSTI ID:7073213

Anderson, R W; Neff, W A

A process is described for removing, from spent electroless metal plating bath solutions, accumulated byproducts and counter-ions that have deleterious effects on plating. The solution, or a portion thereof, is passed through a selected cation exchange resin bed in hydrogen form, the resin selected from strong acid cation exchangers and combinations of intermediate acid cation exchangers with strong acid cation exchangers. Sodium and nickel ions are sorbed in the selected cation exchanger, with little removal of other constituents. The remaining solution is subjected to sulfate removal through precipitation of calcium sulfate hemihydrate using, sequentially, CaO and then CaCO[sub 3]. Phosphite removal from the solution is accomplished by the addition of MgO to form magnesium phosphite trihydrate. The washed precipitates of these steps can be safely discarded in nontoxic land fills, or used in various chemical industries. Finally, any remaining solution can be concentrated, adjusted for pH, and be ready for reuse. The plating metal can be removed from the exchanger with sulfuric acid or with the filtrate from the magnesium phosphite precipitation forming a sulfate of the plating metal for reuse. The process is illustrated as applied to processing electroless nickel plating baths. 18 figs.

• DOE Contract Number: AC05-84OR21400
• Assignee: Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)
• Patent Number(s): US 5112392; A
• Application Number: PPN: US 7-719201
• OSTI ID: 7073213
• Resource Relation: Patent File Date: 21 Jun 1991
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
NICKEL
PLATING
PROCESS SOLUTIONS
DEMETALLIZATION
CALCIUM CARBONATES
CALCIUM OXIDES
ION EXCHANGE
ION EXCHANGE MATERIALS
MAGNESIUM OXIDES
METAL INDUSTRY
RECYCLING
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATES
CHALCOGENIDES
DEPOSITION
DISPERSIONS
ELEMENTS
INDUSTRY
MAGNESIUM COMPOUNDS
MATERIALS
METALS
MIXTURES
OXIDES
OXYGEN COMPOUNDS
SEPARATION PROCESSES
SOLUTIONS
SURFACE COATING
TRANSITION ELEMENTS
320305* - Energy Conservation
Consumption
& Utilization- Industrial & Agricultural Processes- Industrial Waste Management