| 摘要 |
The method concerns treatment of wastewater containing emulsified petroleum substances. It has wide application, particularly in the machine engineering industry. It particularly concerns demulsifying oils from used oil emulsions used when working metals, which is problematic when using existing methods, particularly for demulsifying used oil emulsions of higher concentrations. Adequate effectiveness is often not achieved in the first phase, when quantitative isolation of the oil share should occur. Cleaning in the proposed method is based on the fact that the used oil emulsion is acidified to pH 1.5 to 2.3 by means of spent mordant hydrochloric acid, which, per litre, contains 25 to 30 g soluble bivalent iron and therefore, at the same time as acidification, bivalent iron is added in a quantity of 0.63 to 1.00 g/l and, after subsequent mixing and oxidation of the bivalent iron to trivalent by means of 0.6 to 0.9 g potassium permanganate per 1 litre of demulsified used oil emulsion, the actual demulsifying reaction occurs while mixing with pressurised air with subsequent separation of the oil fraction. After calm flotation, contracture of the free oil fraction occurs and the water is neutralised by sodium or calcium hydroxide to pH 8.5.
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