Solid material comminution or disintegration – Processes – With application of fluid or lubricant material
Patent
1999-08-30
2000-12-26
Rosenbaum, Mark
Solid material comminution or disintegration
Processes
With application of fluid or lubricant material
241 17, 241 21, 241 23, 241 2413, 241 29, B02C 1912
Patent
active
061645710
ABSTRACT:
This invention is based upon the unexpected discovery that the crosslinks in thermoset plastics can be broken by heating to a temperature of at least about 150.degree. C. under a pressure of at least about 3.4.times.10.sup.6 Pascals in the presence of 2-butanol. By utilizing the process of this invention, precious metals can be easily and economically recovered from electronic circuit boards. In this process, the crosslinks in the thermoset plastics in the circuit board break under conditions of heat and pressure in the presence of 2-butanol. After the crosslinks in the thermoset plastic break, the plastic material dissolves in the 2-butanol and can be removed by decanting. The remaining undissolved fiberglass mat and precious metal is removed by filtration, decanting or centrifugation. The precious metals which were entrapped in the thermoset plastic can be recovered from fiberglass on the circuit board by being melted. This invention more specifically discloses a process for recovering a precious metal which is entrapped in a thermoset plastic which comprises the steps of (1) heating the precious metal which is entrapped in the thermoset plastic to a temperature which is within the range of about 150.degree. C. to about 300.degree. C. under a pressure of at least about 3.4.times.10.sup.6 Pascals in the presence of 2-butanol to break the crosslinks in the thermoset plastic to produce a slurry of uncrosslinked plastic material in the 2-butanol and (2) separating the precious metal from the slurry of the uncrosslinked plastic material in 2-butanol.
REFERENCES:
patent: 5887805 (1999-03-01), Chapman
patent: 5891926 (1999-04-01), Hunt et al.
patent: 5979033 (1999-11-01), Chang et al.
Hunt Lawrence Keith
Kovalak Ronald Roy
Rockhill Alvin T
Rosenbaum Mark
The Goodyear Tire & Rubber Company
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