title: A solvent extraction approach to recover acetic acid from mixed waste acids produced during semiconductor wafer process.
abstract: Recovery of acetic acid (HAc) from the waste etching solution discharged from silicon wafer manufacturing process has been attempted by using solvent extraction process. For this purpose 2-ethylhexyl alcohol (EHA) was used as organic solvent. In the pre-treatment stage >99% silicon and hydrofluoric acid was removed from the solution by precipitation. The synthesized product, Na(2)SiF(6) having 98.2% purity was considered of commercial grade having good market value. The waste solution containing 279 g/L acetic acid, 513 g/L nitric acid, 0.9 g/L hydrofluoric acid and 0.030 g/L silicon was used for solvent extraction study. From the batch test results equilibrium conditions for HAc recovery were optimized and found to be 4 stages of extraction at an organic:aqueous (O:A) ratio of 3, 4 stages of scrubbing and 4 stages of stripping at an O:A ratio of 1. Deionized water (DW) was used as stripping agent to elute HAc from organic phase. In the whole batch process 96.3% acetic acid recovery was achieved. Continuous operations were successfully conducted for 100 h using a mixer-settler to examine the feasibility of the extraction system for its possible commercial application. Finally, a complete process flowsheet with material balance for the separation and recovery of HAc has been proposed.
authors.affiliation: R&D Center, Daeil Development Co., Ltd., Ansan 425-836, Republic of Korea. shinch777@chol.com
authors.forename: Chang-Hoon
authors.initials: CH
authors.lastname: Shin
authors.forename: Ju-Yup
authors.initials: JY
authors.lastname: Kim
authors.forename: Jun-Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Hyun-Sang
authors.initials: HS
authors.lastname: Kim
authors.forename: Hyang-Sook
authors.initials: HS
authors.lastname: Lee
authors.forename: Debasish
authors.initials: D
authors.lastname: Mohapatra
authors.forename: Jae-Woo
authors.initials: JW
authors.lastname: Ahn
authors.forename: Jong-Gwan
authors.initials: JG
authors.lastname: Ahn
authors.forename: Wookeun
authors.initials: W
authors.lastname: Bae
mesh_terms: D019342:Acetic Acid / Q000302:isolation & purification*; D000143:Acids / Q000737:chemistry*; D012666:Semiconductors; D012997:Solvents / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000143:Acids; D012997:Solvents; D019342:Acetic Acid