Removal and recovery of nitrogen and sulfur oxides from gaseous mixtures containing them

Patent · Tue Jan 10 04:00:00 EST 1984

OSTI ID:7057910

Cooper, H B.H.

A cyclic process for removing lower valence nitrogen oxides from gaseous mixtures includes treating the mixtures with an aqueous media including alkali metal carbonate and alkali metal bicarbonate and a preoxygen oxidant to form higher valence nitrogen oxides and to capture these oxides as alkali metal salts, expecially nitrites and nitrates, in a carbonate/bicarbonate-containing product aqueous media. Highly selective recovery of nitrates in high purity and yield may then follow, as by crystallization, with the carbonate and bicarbonate alkali metal salts strongly increasing the selectivity and yield of nitrates. The product nitrites are converted to nitrates by oxidation after lowering the product aqueous media pH to below about 9. A cyclic process for removing sulfur oxides from gas mixtures includes treating these mixtures includes treating these mixtures with aqueous media including alkali metal carbonate and alkali metal bicarbonate where the ratio of alkali metal to sulfur dioxide is not less than 2. The sulfur values may be recovered from the resulting carbonate/bicarbonate/-sulfite containing product aqueous media as alkali metal sulfate or sulfite salts which are removed by crystallization from the carbonate-containing product aqueous media. As with the nitrates, the carbonate/bicarbonate system strongly increases yield of sulfate or sulfite during crystallization. Where the gas mixtures include both sulfur dioxide and lower valence nitrogen oxides, the processes for removing lower valence nitrogen oxides and sulfur dioxide may be combined into a single removal/recovery system, or may be effected in sequence.

• Assignee: EDB-84-111059
• Patent Number(s): US 4425313
• OSTI ID: 7057910
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALKALI METAL COMPOUNDS
AQUEOUS SOLUTIONS
CARBON COMPOUNDS
CARBONATES
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CRYSTALLIZATION
DENITRATION
DESULFURIZATION
DISPERSIONS
FLUIDS
GASES
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
MANAGEMENT
MATERIALS RECOVERY
MIXTURES
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PEROXIDES
PH VALUE
PHASE TRANSFORMATIONS
POTASSIUM CARBONATES
POTASSIUM COMPOUNDS
POTASSIUM SULFATES
PROCESSING
RECOVERY
SODIUM CARBONATES
SODIUM COMPOUNDS
SOLUTIONS
SULFATES
SULFUR COMPOUNDS
SULFUR OXIDES
WASTE MANAGEMENT
WASTE PROCESSING
WASTE PRODUCT UTILIZATION