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Solids Sedimentation & Water Recovery in Rolling Mill Scale Pits
Protection of circulation pumps by separating fine iron oxide particles and oil in the scale pit water in iron-steel hot rolling lines.
High flow rate cooling and descaling waters used in iron-steel hot rolling and continuous casting lines; It carries iron oxide (FeO, Fe₃O₄, Fe₂O₃) scale in different grain sizes, submicron metallic particles, and grease and emulsified oils leaking from bearing/hydraulic systems.
Even if coarse scale pieces settle mechanically in the primary scale pit, fine scale particles remain suspended at high surface velocities and can reach circulation pumps, sand filters and high-pressure descaling nozzles, creating erosion. Elif Çevre Kimya's iron and steel sector solutions include high intrinsic viscosity A-PAM polymers and oil emulsion breakers for hot scale waters.
The first step in the design of scale pit and lamellar settler is to separate the free oil and grease on the surface with skimmers. Dosing polymer directly in water with a high oil content can create oil-covered sludge lumps, which can both clog sand filters and deteriorate the quality of the scooped scale.
After appropriate pre-separation, the temperature-stable anionic polyelectrolyte (A-PAM) and, if necessary, the inorganic coagulant/emulsion breaker combination are compared with the Jar-Test on the sample. The dosage point of the polymer, channel turbulence and precipitator surface charge are optimized together.
In order to re-introduce the purified water to the mill cooling/descaling circuit, outlet AKM, oil-grease and conductivity values should be monitored; It should not be assumed that the settled scale mud is suitable for direct sinter or melting recovery without analyzing its moisture and oil content. Dosage or recovery performance is not guaranteed without analysis and field testing.
Don't See the Scale Pit Water as Just Turbidity
High flow rate cooling and descaling waters used in iron-steel hot rolling and continuous casting lines; It carries iron oxide (FeO, Fe₃O₄, Fe₂O₃) scale in different grain sizes, submicron metallic particles, and grease and emulsified oils leaking from bearing/hydraulic systems. Even if coarse scale pieces settle mechanically in the primary scale pit, fine scale particles remain suspended at high surface velocities and can reach circulation pumps, sand filters and high-pressure descaling nozzles, creating erosion. Elif Çevre Kimya's iron and steel sector solutions include high intrinsic viscosity A-PAM polymers and oil emulsion breakers for hot scale waters.
Temperature, Oil Presence and Precipitation Approach
The first step in the design of scale pit and lamellar settler is to separate the free oil and grease on the surface with skimmers. Dosing polymer directly in water with a high oil content can create oil-covered sludge lumps, which can both clog sand filters and deteriorate the quality of the scooped scale. After appropriate pre-separation, the temperature-stable anionic polyelectrolyte (A-PAM) and, if necessary, the inorganic coagulant/emulsion breaker combination are compared with the Jar-Test on the sample. The dosage point of the polymer, channel turbulence and precipitator surface charge are optimized together.
What Data Is Water and Scale Recovery Decision Based On?
In order to re-introduce the purified water to the mill cooling/descaling circuit, outlet AKM, oil-grease and conductivity values should be monitored; It should not be assumed that the settled scale mud is suitable for direct sinter or melting recovery without analyzing its moisture and oil content. Dosage or recovery performance is not guaranteed without analysis and field testing.
Field Control and Monitoring List
Chemical dosage and system capacity decisions should be determined by analysis and facility conditions; There is no guarantee of fixed dosage or performance.
- Measurement of temperature (°C), TSS (mg/L) and free/emulsified oil in scale pit inlet and outlet water
- Control of oil skimmer and coarse scale scooping period in the primary pit
- Selection of high molecular weight A-PAM that is resistant to hydrolysis in hot rolling waters at 60°C+
- Monitoring the outlet AKM trend before sand filters and high pressure descaling nozzles
- Verification of oil and moisture percentage in collected scale sludge with recovery criteria
- Check out Iron and Steel Industry Solutions
- Scale Pit Jar-Test & Request a Quote
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- 15. Colour, Emulsion and Foam in Textile and Process Wastewater: Different Problem, Different Test