Development of an inter-process linkage technology for fluoro-nitric acid washing-agent and its LCA evaluation

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 byproduct 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.