Development of Vacuum Evaporation Regeneration System for Waste Acid in Superconducting Material Cleaning Industry

ZHANG Wan-jun, FANG Xiang-ming, JIA Qing-gong, PENG Chang-hu

Surface Technology ›› 2014, Vol. 43 ›› Issue (3) : 105-110.

PDF(4507 KB)
PDF(4507 KB)
Surface Technology ›› 2014, Vol. 43 ›› Issue (3) : 105-110.

Development of Vacuum Evaporation Regeneration System for Waste Acid in Superconducting Material Cleaning Industry

  • ZHANG Wan-jun, FANG Xiang-ming, JIA Qing-gong, PENG Chang-hu
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Abstract

Objective To study the treatment and recycle technology of waste acid generated during the cleaning process of superconducting material, in order to realize the purification and reuse of waste acid, reaching the goal of zero release of waste acid.Methods Concentrated sulfuric acid was mixed with the waste acid liquid to provide the suitable concentration, then the mixture was evaporated in a vacuum environment under 25 kPa, where the acid evaporator was condensed and regenerated,and metal crystals were obtained from the enriched melt sulfate solution after cooling at room temperature. A whole set of corrosion resistant equipment were designed and developed according to the requirements of mixing acid, evaporation, condensation and crystallization.The process details were validated and optimized with commissioning. Results Totally 9 ~ 15 tons of waste acid was treated daily with the system. The regenerated acid could be reused after concentration adjustment, and the sulfate crystals from the concentrated liquid could be used raw materials for other chemicals. Conclusion Nitric acid and hydrofluoric acid for cleaning of superconducting material were successfully regenerated and reused. No pollutant was discharged in the whole process. Meanwhile, the equipment had a number of advantages, such as stability, reliability, low cost and low maintenance.

Key words

superconducting material; negative pressure evaporation; pickling; waste acid; regeneration

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ZHANG Wan-jun, FANG Xiang-ming, JIA Qing-gong, PENG Chang-hu. Development of Vacuum Evaporation Regeneration System for Waste Acid in Superconducting Material Cleaning Industry[J]. Surface Technology. 2014, 43(3): 105-110
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