초록 ▼

불산/질산/초산으로 구성된 폐혼합산으로부터 각 산을 분리하여 재활용하는 연구를 수행하였다. 용매추출법으로 불산을 회수할 경우 양이 적고 농도가 낮아 재활용하기 어려워 불산을 침전시켜 회수한 후 질산/초산의 2성분계 혼산에 대한 연구를 하였다. 이에 불산을 Na2SiF6의 형태로 침전시켜 회수하였고, 그 회수율은 99%이상이었다.
불산이 제거된 질산/초산의 2성분계 폐혼산을 각 산으로 분리하여 회수하기 위해 용매추출법과 분별증류법의 bench scale 실험을 수행하였다. 초산 회수율 90%이상의 순수 초산을 회수하였고, 경

불산/질산/초산으로 구성된 폐혼합산으로부터 각 산을 분리하여 재활용하는 연구를 수행하였다. 용매추출법으로 불산을 회수할 경우 양이 적고 농도가 낮아 재활용하기 어려워 불산을 침전시켜 회수한 후 질산/초산의 2성분계 혼산에 대한 연구를 하였다. 이에 불산을 Na2SiF6의 형태로 침전시켜 회수하였고, 그 회수율은 99%이상이었다.
불산이 제거된 질산/초산의 2성분계 폐혼산을 각 산으로 분리하여 회수하기 위해 용매추출법과 분별증류법의 bench scale 실험을 수행하였다. 초산 회수율 90%이상의 순수 초산을 회수하였고, 경제성면에서 용매추출보다 분별증류방법이 더 우수하였다.
분별증류법을 이용한 질산/초산 pilot plant를 4톤/일 처리규모로 설치하였고, 초산회수율 84%이상, 농도 99.5%의 초산회수가 가능함을 확인하였다.
질산/불산에 대한 STS산세액 재활용 연구에서는 온도가 높아질수록 광택도가 나빠졌고, 산세 시간이 길어질수록 백색도 및 광택도가 증가하였으며, 현장 모의 실험 결과, P사 생산품의 90%수준으로 산세되었다.

Abstract ▼

Ⅰ. Title

Development of environmental technology for recycling multicomponent waste acid including hydrofluoric acid and acetic acid

Ⅱ. Brief introduction of the present work

In factories manufacturing electronic parts such as semiconduct or LCD, large amount of mixed waste ac

Ⅰ. Title

Development of environmental technology for recycling multicomponent waste acid including hydrofluoric acid and acetic acid

Ⅱ. Brief introduction of the present work

In factories manufacturing electronic parts such as semiconduct or LCD, large amount of mixed waste acid is produced because etching process with acid-mixture is performed. Namely, in silicon wafer manufacturing stage, procedures are carried out from single silicon solution to wafer cutting, mechanical polishing, chemical etching, mechanical & chemical polishing, and washing. Acid mixture of nitric acid, hydrofluoric acid, and acetic acid are used for etching solution in chemical etching process.
Large amount of etching waste acid liquid is produced because etching effectiveness goes down as this chemical etching progress goes on. In case of hydrofluoric etching waste acid, the amount produced grow along with bigger consumption of silicon wafer. Also, in present LCD manufacturing process, mixed waste acid consisting of phosphoric acid, nitric acid, and acetic acid, which is for etching Al and Mo, is produced in quantity. In this case, only phosphoric acid is recollected and recycled for the use of fertilizer, but the present situation is that acetic acid is only disposed owing to not finding right way of recollecting.
Therefore, in this study economic and environment-friendly plan for separating and recycling of acid in mixed waste acid.

Ⅲ. Contents and scope of the present research

1. Technological development of separating respective acid from mixed acid consisting of nitric acid, hydrofluoric acid, and acetic acid using solvent extraction.
2. Technological development of producing hydrofluoric mixture from the mixed acid of nitric acid, hydrofluoric acid, and acetic acid.
3. Bench-scale-sized solvent extraction test in size of 50kg/day to separate each acid from the mixed waste of nitric acid and acetic acid.
4. Bench-scale-sized sorting distillation test to separate each acid from the mixed waste of nitric acid and acetic acid.
5. Pilot-scale-sized sorting distillation test in size of 4ton/day to separate each acid from the mixed waste of nitric acid and acetic acid.
6. Technological development of recycling STS acid waste liquid.

Ⅳ. Results of the present work

1. Technology of extracting acetic acid, nitric acid, and hydrofluoric acid from mixed waste acid was completed.
2. Technology of producing hydrofluoric precipitate in the form of Na2SiF6 was completed, when hydrofluoric acid recovery rate was >99%.
3. Bench scale sized solvent extraction test and sorting distillation test for separating each acid from the mixture of nitric acid and acetic acid were carried out, when acetic acid recovery rate was >90%. Sorting distillation was more cost-effective than solvent extraction.
4. Pilot plant sized sorting distillation test in size of 4ton/day(166kg/hr) was carried out for separating each acid from the mixture of nitric acid and acetic acid. Then, nitric acid recovery rate was >90% and recovery density was >84%. Acetic acid recovery rate was >84% and recovery density was 99.5%.
5. Technology of purifying and recycling STS acid waste liquid was achieved. The result from on-spot application test reached 90% level of P company product.

Ⅴ. Application of the results obtained from the present research

It is planned that the contract will be made with joining partners, and a nitric/acetic acid sorting distillation plant with capacity of 1.5 ton/hr will be founded. And also hydrofluoric mixture manufacturing facility with capacity of 0.5ton/hr to dispose mixed waste acid of nitric acid, hydrofluoric acid, and acetic acid will be founded.

목차 Contents

• 제출문 ...1
• 보고서 초록 ...3
• 요 약 문 ...5
• SUMMARY ...7
• CONTENTS ...10
• 목 차 ...12
• 표 목차 ...14
• 그 림 목차 ...17
• 제1장 연구개발과제의 개요 ...23
• 1절. 연구개발의 필요성 ...23
• 제2장 국내외 기술개발 현황 ...29
• 1절. 시장현황 ...29
• 2절. 국외기술현황 ...33
• 3절. 국내기술현황 ...35
• 제3장 연구개발수행 내용 및 결과 ...39
• 1절. 기술 개요 ...39
• 2절. 질/불/초 혼산의 각 산 분리.회수를 위한 용매추출 ...67
• 3절. 불산 제거 및 초산회수를 위한 Bench-Scale Test ...96
• 4절. Pilot Test ...183
• 5절. 스테인리스스틸(STS) 산세액으로 재활용 ...219
• 제4장 목표 달성도 및 관련분야에의 기여도 ...259
• 제5장 연구개발 결과의 활용계획 ...261
• 제6장 연구개발과정에서 수집한 해외과학기술정보 ...265
• 제7장 참고문헌 ...269