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Enhancing the Dewaterability of Oily Cold Rolling Mill Sludge Using Quicklime as a Conditioning Agent
Qingyu Tang1, Jinxin Xing1, Zengqing Sun1
1School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, China.
ACS Omega
|December 12, 2022
Summary
Quicklime effectively dewaters oily cold rolling mill (CRM) sludge, improving recycling potential. This green approach transforms waste into ironmaking raw material, enhancing sustainability.
Area of Science:
- Environmental Engineering
- Materials Science
Background:
- Oily cold rolling mill (CRM) sludge presents recycling challenges due to high moisture and viscosity.
- Effective dewatering is crucial for sludge valorization and waste management.
Purpose of the Study:
- To investigate the use of quicklime as a conditioning agent to enhance the dewaterability of oily CRM sludge.
- To determine the optimal conditions for quicklime treatment and assess its impact on sludge properties and filtrate quality.
Main Methods:
- Conditioning-dewatering experiments were conducted using quicklime on oily CRM sludge.
- Optimized parameters included quicklime dosage (10%), temperature (60 °C), liquid/solid ratio (1.5:1), and time (30 min).
- Evaluated changes in specific resistance to filtration, compressibility, dewatering rate, and filtrate characteristics.
Main Results:
- Quicklime significantly improved sludge dewaterability, reducing specific resistance to filtration by 95.9%.
- The dewatering rate increased from 9.0 to 52.6%, and filter cake compressibility decreased.
- Treated sludge formed an incompressible rigid porous structure, and filtrate quality improved (reduced oil, COD, turbidity).
Conclusions:
- Quicklime is an effective conditioning agent for oily CRM sludge, enabling efficient dewatering and improved filter cake properties.
- The conditioned sludge meets ironmaking raw material requirements, offering a sustainable waste recovery solution.
- This method provides a green approach to oily CRM sludge management and promotes circular economy principles.
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