Study on Gradient Separation of Targeted Components and Acid Regeneration from Stainless Steel Pickling Wastewater
Received:March 25, 2019   Revised:March 27, 2019   Accepted:March 28, 2019      Published Online:August 16, 2019
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DOI:doi:10.3969/j.issn.1007-7545.2019.09.005
KeyWord:pickling wastewater; defluorination; metal separation; nitric acid regeneration; calcium sulfate whiskers
                 
AuthorInstitution
MA Bao-zhong 北京科技大学冶金与生态工程学院
LI Xiang 北京科技大学冶金与生态工程学院
SHAO Shuang 北京科技大学冶金与生态工程学院
ZHANG Wen-juan 北京科技大学冶金与生态工程学院
WANG Cheng-yan 北京科技大学冶金与生态工程学院
CHEN Yong-qiang 北京科技大学冶金与生态工程学院
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Abstract:
      Stainless steel pickling liquor is usually neutralized by lime, which produces a large amount of hazardous solid waste (calcium sulfate slag). Gradient separation of targeted components in stainless steel pickling liquor, regeneration of nitric acid by sulfuric acid and coupling synthesis calcium sulfate whiskers with high aspect ratio were studied. Effects of factors on experimental results during fluoride ion removal in high acid environment, gradient separation of valuable metals, and acid regeneration were systematically investigated. Morphology of calcium sulfate whiskers synthesized by coupling reaction in acid regeneration was analyzed by SEM to determine the optimum technological conditions of each process. The results show that fluoride ion removal rate under high acid environment is 97% above, precipitation rate of iron, nickel and chromium is all 99.9% above. Nitric acid is efficiently regenerated and calcium sulfate whiskers are synthesized by coupling reaction. Regeneration rate of nitric acid is 95% above and concentration of nitric acid regenerated exceeds 143 g/L. A reliable and stable new technology to treat stainless steel pickling wastewater is provided.
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