Treatment of Stainless Steel Rinse Waters Using Non-Dispersive Extraction and Strip Dispersion Membrane Technology

Area of Science:

• Environmental Engineering
• Materials Science
• Chemical Engineering

Background:

• Stainless steel manufacturing generates rinse water containing heavy metals like Fe(III), Cr(III), and Ni(II).
• Efficient and environmentally sound methods are needed for metal recovery from industrial wastewater.

Purpose of the Study:

• To investigate the efficacy of non-dispersive extraction and strip dispersion membrane technology for separating and concentrating Fe(III), Cr(III), and Ni(II).
• To optimize process parameters for metal recovery from stainless steel rinse water.

Main Methods:

• Utilized a microporous hydrophobic hollow-fibre module contactor with polypropylene fibres.
• Employed bis(2-ethylhexyl) phosphoric acid (DP8R) in ExxsolD100 as the organic extractant.
• Implemented a counter-current flow of rinse water and a pseudo-emulsion of organic phase and acidic strip solution.

Main Results:

• Successfully separated and concentrated Fe(III), Cr(III), and Ni(II) from the rinse water.
• Investigated the impact of hydrodynamic and chemical variables on metal extraction efficiency.
• Estimated mass transfer coefficients to evaluate the process performance.

Conclusions:

• Non-dispersive extraction and strip dispersion membrane technology is a viable method for metal separation and concentration from industrial wastewater.
• The developed hollow-fibre module system offers an efficient approach for recovering valuable metals from stainless steel rinse water.