Oily cold rolling mill sludge conditioned by quicklime to improve dewatering performance: optimization and mechanism...

Area of Science:

• Environmental Engineering
• Materials Science

Background:

• Oily cold rolling mill (CRM) sludge requires efficient dewatering for treatment and recycling.
• Current dewatering technologies for oily CRM sludge lack efficiency and energy savings.

Purpose of the Study:

• To investigate quicklime as a conditioning agent for oily CRM sludge dewatering.
• To determine optimal parameters for quicklime conditioning using response surface methodology (RSM).

Main Methods:

• Response surface methodology (RSM) was employed to study the effects of quicklime dosage, temperature, and time.
• Evaluated filter cake's specific resistance to filtration (SRF) and dewatering rate.
• Analyzed viscosity reduction of conditioned sludge.

Main Results:

• Optimal conditioning parameters: 18.7% quicklime dosage, 54 °C, and 43.3 min.
• Achieved filter cake SRF of 0.50 × 10¹⁰ m/kg and a dewatering rate of 61.2%.
• Quicklime reduced sludge viscosity by 90% through neutralization/hydrolysis of organic matter.

Conclusions:

• Quicklime demonstrates excellent performance as a conditioning agent for oily CRM sludge.
• This method provides an effective route for recycling oily CRM sludge in steel production.
• Quicklime offers an energy-saving and applicable dewatering solution.