Fluoro-nitric acid-used in the semiconductor industry as a washing agent is of high purity and high concentration (fluoric acid: 23.3%, nitric acid: 16.6%). It is recovered using separation and control in the semiconductor industry. A technology-for utilizing this acid by product as-a pickling. solution for stainless steel sheets in the steel industry was developed. The results of a, Life-Cycle. Assessment study showed that a cascade of 10 tons of acid byproducts reduces-energy consumption by 4.0 tons in crude oil conversion value, CO2 emissions by 4.3 tons, and sludge generation-by 24.8 tons. (C) 2004 Elsevier Ltd. All rights reserved.