US 5,320,817 AGranted

Process for sorption of hazardous waste products from exhaust gas streams

AssigneeNovapure Corporation

InventorsSteven Hardwick, James V. McManus

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Abstract

A method for cleaning an exhaust gas containing ammonia and at least one silicon-containing compound selected from the group consisting of silane and chlorosilanes, which comprises contacting the exhaust gas with a scavenger comprising a metal salt which forms tight complexes with ammonia. This ammine-forming metal salt may be immobilized on a porous solid support. Suitable ammine-forming metal salts include the sulfates, nitrates, chlorides, bromides, iodides, and hydroxides of copper, cobalt, iron, and nickel. Suitable supports include materials which are compatible with the gas mixtures being cleaned and the reaction products of the sorption process and which are stable under the conditions of use. Useful support materials include zeolites, aluminosilicates, alumina, silica, silica gel, kieselguhr, and activated carbon.

Claims10

Dependent claims

A dry scrubbing method for cleaning a gas mixture containing ammonia and least one silicon-containing gaseous component selected from the group consisting of silane and chlorosilanes, wherein the ratio R of the concentration of ammonia to the concentration of said at least one silicon-containing gaseous component in said gas mixture, is governed by the relationship:

1<R.ltoreq.14,
to yield treated gas having a reduced content of ammonia and said silicon-containing gaseous component, which comprises contacting the exhaust gas for sufficient time and at sufficient conditions with a bed of scavenger comprising an ammine-forming metal salt immobilized on a porous solid support, wherein the metal salt is (i) selected from the group consisting of sulfates, nitrates, chlorides, bromides, and iodides of copper, cobalt, iron, nickel, chromium, rhodium, palladium and platinum, and (ii) present on the support at a concentration of from 0.25 moles of metal per liter of scavenger to 2 moles metal per liter of scavenger.

Dependencies are inferred from the claim text.