Chemical Selection for Flocculation of the Sludges Produced During Lime Neutralization of Acidic Spent Pickling Solutions and Rinse Water from Steel Pipe Mill


Acidic spent pickling solutions and rinse water are produced during steel pipe acid pickling. They are usually neutralised with lime in a neutralisation plant and pumped in the form of a wet sludge to a landfill. This is one of the main environmental issues of Russian steel mills. The implementation of sludge treatment units, including equipment for sludge polymer conditioning and dewatering, is an import consideration when seeking to reduce the impact of steel mills on human health and the environment. The researches results of polymer conditioning of the aggressive wastewater sludges by flocculants are reflected in the paper. Sludge samples were obtained from the neutralisation plant of an Ural’s steel pipe mill. Sludges of two types were investigated: the sludge which is formed in clarifiers during spent pickling solutions neutralization with lime and the sludge which is formed in clarifiers during rinse water neutralization with lime. During the work non-ionic, cationic, and anion flocculants Praestol® efficiency was estimated. The shortest time of water capillary suction from the flocculated sludge was accepted as efficiency criterion of flocculant processing. It was defined with use of the capillary suction timer Fann® and Whatman® 17 chromatographic paper. It is established that: non-ionic focculant Praestol® 2500 dose of 4–5 g/kg dry solids is effective for conditioning of the sludge produced during lime neutralization of acid spent pickling solutions; the anionic flocculant Praestol® 2540 dose of 1.5–2 g/kg dry solids is effective for conditioning of the sludge produced during lime neutralization of acid rinse water. The empirical response surfaces and the contour plots showing the relationship between capillary suction time and a dosage of flocculant and a charge density (% hydrolysis) of a flocculant were reveived.

Keywords: steel pipe mill, acid pickling, wastewater, sludges, flocculants, capillary suction time

[1] Bratby, J. (2016). Coagulation and Flocculation in Water and Wastewater Treatment. London: IWA publishing.

[2] Sabah, E. and Cengiz, I. (2004). An Evaluation Procedure for Flocculation of Coal Preparation Plant Tailings. Water Research, vol. 38, issue 6, pp. 1542–1549.

[3] Kumar, S., Mandre, N. R. and Bhattacharya, S. (2016). Flocculation Studies of Coal Tailings and the Development of a Settling Index. International Journal of Coal Preparation and Utilization, vol. 36, issue 6, pp. 293–305.

[4] Ng, W. S., et al. (2015). Flocculation/Flotation of Hematite Fines with Anionic Temperature-responsive Polymer Acting as a Selective Flocculant and Collector. Minerals Engineering, vol. 77, pp. 64–71.

[5] Castro, S. and Laskowski, J. S. (2015). Depressing Effect of Flocculants on Molybdenite Flotation. Minerals Engineering, vol. 74, pp. 13–19.

[6] Chanturia, V. A., et al. (2016). Mechanism of Interaction of Cloud Point Polymers with Platinum and Gold in Flotation of Finely Disseminated Precious Metal Ores. Mineral Processing and Extractive Metallurgy Review, vol. 37, issue 3, pp. 187–195.

[7] Manna, M. (2019). Optimization of Flocculation Process to Selectively Separate Iron Minerals from Rejected Iron Ultra Fines of Indian Mines and Minimize Environmental Issue. ISIJ International, vol. 59, issue 6, pp. 1145–1151.

[8] Morrissey, K. L., et al. (2016). Polyamphoteric Flocculants for the Enhanced Separation of Cellular Suspensions. Acta biomaterialia, vol. 40, pp. 192–200.

[9] Azeredo, D. R., et al. (2016). An Overview of Microorganisms and Factors Contributing for the Microbial Stability of Carbonated Soft Drinks. Food Research International, vol. 82, pp. 136–144.

[10] Khan, J. R., et al. (2016). Brine Purification for Chlor-Alkalis Production Based on Membrane Technology. Pakistan Journal of Engineering and Applied Sciences, vol. 16, pp. 17–24.

[11] Dobias, B. and Stechemesser, H. (Eds.). (2005). Coagulation and Flocculation: Theory and Applications. Boca Raton: CRC Press.

[12] Somasundaran, P. and Moudgil, B. M. (2018). Reagents in Mineral Technology. London: Routledge.

[13] Lee, C. S., Robinson, J. and Chong, M. F. (2014). A Review on Application of Flocculants in Wastewater
Treatment. Process Safety and Environmental Protection, issue 92(6), pp. 489–508.

[14] Teh, C. Y., et al. (2016). Recent Advancement of Coagulation–Flocculation and Its Application in Wastewater Treatment. Industrial & Engineering Chemistry Research, vol. 55, issue 16, pp. 4363-4389.

[15] Ksenofontov, B. S. and Goncharenko, E. E. (2018). Use of Active Silt After Preliminary Floatation Processing as Bioflokulyant. Ecology and Industry of Russia, vol. 22, issue 3, pp. 10–14.

[16] Ksenofontov, B. S. and Goncharenko, E. E. (2016). Intensification of Purification of Surface Sewage by Use a Bioflocculant. Herald of the Bauman Moscow State Technical University, Series Natural Sciences, issue 3, pp. 118–127.

[17] Wei, H., et al. (2018). Coagulation/Flocculation in Dewatering of Sludge: A Review. Water Research, vol. 143, pp. 608–631.

[18] Aksenov,V.I.,Tsarev,N.S.andYasnitskaya,K.V.(2016).TreatmentoftheCombinedSludgesofMachine Factories. Procedia Engineering, vol. 150, pp. 2405–2408.

[19] Vesilind, P. A. (1988). Capillary Suction Time as a Fundamental Measure of Sludge Dewaterability. Journal (Water Pollution Control Federation), vol. 60, issue 2, pp. 215–220.

[20] Sennerfors, T. (2015). Polymer–Nanoparticle Complexes: Interfacial Behavior Applications. In Encyclo- pedia of Surface and Colloid Science, pp. 5765–5775. Boca Raton: CRC Press.