INFLUENCE OF ACID AND CHLORIDE CONCENTRATIONS ON CORROSION IN A NITRIC ACID CONCENTRATOR
Experience with corrosion in a large concentrator used to recover nitric acid from raffinate waste products in a uranium refining plant is related. Solution of the corrosion problem in the concentrator involved generation of ozone by electrical discharge generators to oxidize chlorides to produce chlorine. An electrolytic cell also was used to remove chlorides. Chlorides concentrated in that portion of the tower where acid concentration was 20 to 30% necessitating frequent replacement of bubble caps and other parts. Areas subjected to high velocities had abnormally high corrosion rates. Results of tests on Hastelloy C, Carpenter 20, Ni-O-Nel, Incoloy, Inconel, and various stainless steels are tabulated for 25 to 35%, acid strength with 550 ppm chlorides and for 30 to 40% acid with 800 to 900 ppm chlorides. A corrosion profile of the concentrator from Trays 1 to 12 in both acid and vapor phases is given. Several conclusions are listed including one that chloride removal by electrolysis in not more efficient or less expensive than by ozonation until concentrations exceed 1000 ppm. The 18-8 series stainless suffered negligible corrosion up to 200 ppm chlorides, and tolerable rates when chlorides are below 600 ppm at low flow velocities. At chloride concentrations over 900 ppm, corrosion of 18-8 was excessive. (auth)
- Research Organization:
- Eldorado Mining and Refining Ltd., Port Hope, Ont.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-15-011527
- OSTI ID:
- 4079996
- Journal Information:
- Corrosion, Journal Name: Corrosion Vol. Vol: 17: No. 3
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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