Preparation Of Oily Sludge Emulsions And Their Coal Flotation Performance

Oily sludge is a hazardous waste in the exploitation, transportation, processing and refining process of crude oil. Traditional oily sludge treatment technology is difficult and suffers from high cost. This paper focuses on the preparation and application of coal flotation agent from oily sludge, which effectively eliminate pollution and realize the resource utilization of oily sludge, and reduce the flotation costs.This paper systematically tested the basic properties of oily sludge from Yanchang Petroleum Group Xiasiwan oil production factory, such as industrial analysis, element analysis, viscosity, freezing point and density etc. The results showed that the oil content of oil sludge was 43.01%, the viscosity was 1081 mPa · s, the density was 0.99 g/m3, the solidifying point was 28.5 ℃, and the oily sludge’s liquidity was poor.Oily sludge was adopted as main raw material to prepare oily sludge emulsion, and the type, stability and dispersion of the emulsion were characterized. In order to investigate the coal flotation performance of the oily sludge emulsions, the experiment used 3 kinds of different coalification range. The results showed that the oily sludge emulsions were of oil-in-water type. The average size of the oily sludge emulsions was about 4.8 μm. The oily sludge emulsions kept stable for 90 d at room temperature. The optimum conditions for the Hancheng coal flotation was as follows: the collector concentration was 9.0 kg/t, the foaming agent concentration was 0.3 kg/t and the coal pulp concentration was 100 g/L; The optimum conditions for the Taixi coal flotation was as follows: the collector concentration was 3.0 kg/t,the foaming agent concentration was 0.2 kg/t and the coal pulp concentration was 100 g/L;The optimum conditions for the Fuxian coal flotation was as follows: the collector concentration was 1.0 kg/t, the foaming agent concentration was 0.1 kg/t and the coal pulp concentration was 100 g/L; The coal flotation performance of the Oily sludge emulsions was better than that of kerosene, while the former was much cheaper. The coal flotation with the oily sludge emulsions as collector had better selective in all particles of Hancheng coal andbetter flotability in large particles; It had better selective in all particles of Taixi coal and better flotability in small particles; It had better selective and flotability in large particles of Fuxian coal.This article analyzed the flotation mechanism of oily sludge emulsion as collector. The results showed that the contact angle of the coal sample treated with oily sludge emulsion can be increased to different extent, the number of hydrophobic functional group on coal particle surface was increased, the absolute value of Zeta potential was decreased, and the hydrophobicity and flotability of coal particle surface improved.