Claims
- 1. An acid reprocessor for reprocessing waste piranha containing contaminated sulfuric acid (H.sub.2 SO.sub.4) from a semiconductor processing operation, said acid reprocessor comprising:
- an input flask means for receiving said waste piranha containing contaminated H.sub.2 SO.sub.4, light boiling contaminants, water and particulates, said input flask means including a first heating means for heating said waste piranha, said input flask means having an output for outputting said waste piranha;
- a first distillation means having an input coupled to said output of said input flask means to receive said waste piranha and having a gaseous output being coupled to a first column packed with a column packing means, said first distillation means having a second heating means for heating said waste piranha to boil off said water and said light boiling contaminants from said waste piranha to produce an enriched acid, said contaminants escaping from said gaseous output through said first column and through a mist eliminator means of said first distillation means, said first column having an input to receive reflux liquid which is trickled through said column to retard loss of H.sub.2 SO.sub.4 in said first distillation means, said first distillation means having a feed output for providing said enriched acid;
- a second distillation means having an input coupled to said feed output for receiving said enriched acid, said second distillation means having a third heating means for heating said enriched acid to boil off substantially pure H.sub.2 SO.sub.4, through a second column leaving an acid waste sludge in said second distillation means, said second distillation means having a first output for providing said substantially pure H.sub.2 SO.sub.4, said first output being coupled to a condenser to condense said substantially pure H.sub.2 SO.sub.4, said condenser having a first coil through which a coolant flows to cool the substantially pure H.sub.2 SO.sub.4 which flows through said condenser, said second distillation means having a second output for continuously purging said acid waste sludge from said second distillation means, said second distillation means having a structure being comprised substantially of borosilicate glass;
- a heat exchanger means having a cooling means including a second coil through which a coolant flows and having a first input coupled to said gaseous output of said first distillation means to receive said water and said light boiling contaminants escaping from said first distillation means and having a second input coupled to said second output of said second distillation means to receive said acid waste sludge, said heat exchanger means having a third column packed with column packing means and having an input to receive waste acid which is trickled through said third column;
- a vacuum generation means coupled to provide a vacuum in said first distillation means and in said second distillation means, said vacuum generation means producing a vacuum in said second distillation means to reduce said contaminants of said substantially pure H.sub.2 SO.sub.4, whereby said acid reprocessor provides a reprocessed semiconductor grade H.sub.2 SO.sub.4 from waste piranha of a semiconductor processing operation.
- 2. The acid reprocessor as described in claim 1 wherein said input to receive waste acid which is trickled through said third column provides a means for setting the minimum vacuum pressure in the distillation system and wherein said first distillation means is a structure being comprised substantially of borosilicate glass.
- 3. An acid reprocessor for reprocessing waste piranha containing contaminated H.sub.2 SO.sub.4 from a semiconductor processing operation, said acid reprocessor comprising:
- an input flask means for receiving said waste piranha containing contaminated H.sub.2 SO.sub.4 light boiling contaminants, particulates and water, said input flash means having an output for outputting said waste piranha;
- a first distillation means having an input coupled to said output of said input flask means to receive said waste piranha and having a gaseous output being coupled to a first column packed with a column packing means, a first heating means for heating said waste piranha in said first distillation means to boil off water and other light boiling contaminants from said waste piranha to produce an enriched acid, said light boiling contaminants and water escaping from said gaseous output through said first column of said first distillation means, an input in said first column to receive reflux liquid which is trickled through said first column to retard loss of H.sub.2 SO.sub.4 in said first distillation means, a feed output from said distillation means for said enriched acid;
- a second distillation means having an input coupled to said feed output for receiving said enriched acid, a second heating means for heating said enriched acid in said second distillation means to boil off substantially pure H.sub.2 SO.sub.4, through a second column leaving an acid waste sludge in said second distillation means, said second distillation means having a first output for providing said substantially pure H.sub.2 SO.sub.4, said first output being coupled to a condenser to condense said substantially pure H.sub.2 SO.sub.4, said second distillation means having a second output for removing continuously said acid waste sludge from said second distillation means;
- a vacuum generation means coupled to said first and second distillation means, providing a reduced operating pressure in said first and second distillation means, such that said particulates remain in said acid waste sludge;
- a heat exchanger means having a third column and a cooling means, said heat exchanger means having a first input coupled to said gaseous output of said first distillation means to receive said water and said light boiling contaminants from said first distillation means and having a second input coupled to said second output of said second distillation means to receive said acid waste sludge, said cooling means including a first chamber through which a coolant flows to cool said acid waste sludge, said third column being packed with a column packing means and being coupled to said vacuum generation means to provide said reduced operating pressure in said first and said second distillation means, said third column having a third input to receive a waste acid which is trickled through said third column, such that said third input provides a means for setting the minimum vacuum pressure in the distillation system and for removing any acid vapor from a vapor stream created in said heat exchanger means, said heat exchanger being coupled to said waste collection tank to provide for removal of said acid waste sludge from said second distillation means through said second output of said second distillation means; and
- a waste collection tank providing for removal of said acid waste sludge from said second distillation means through said second output.
- 4. The acid reprocessor as described in claim 3 wherein said first distillation means, said second distillation means and said heat exchanger means are comprised of substantially a borosilicate glass.
- 5. An acid reprocessor as in claim 3 further comprising a valve means coupled to said second output of said second distillation means to control the rate of removal of said acid waste sludge from said second distillation means, wherein said valve is periodically opened and closed to continuously remove said acid waste sludge from said second distillation means.
BACKGROUND OF THE INVENTION
This is a continuation of application Ser. No. 07/261,916, filed 10/24/88 now abandoned, which is a continuation in part of application Ser. No. 07/231,849, filed Aug. 12, 1988, by the instant inventors and now U.S. Pat. No. 4,980,032.
US Referenced Citations (28)
Foreign Referenced Citations (1)
Number |
Date |
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139306 |
Oct 1960 |
SUX |
Continuations (1)
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Date |
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261916 |
Oct 1988 |
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Continuation in Parts (1)
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231849 |
Aug 1988 |
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