While fly-ash is a pollutant, the products of fly-ash decarburization can be re-used in cement and power production. This paper describes a new method to reduce the high carbon concentration of a wet fly-ash from a power plant in Guangdong province (China) by using a flotation process.  In this study, laboratory and industrial experiments were done mainly by basic physical and chemical analysis and flotation cell and flotation column experiments. To fundamentally understand the characteristics of fly-ash, its mineral composition, chemical composition, and physical and chemical properties were determined. The results showed that the 35.48% particle of this fly-ash was smaller than 0.008mm and its floatability was poor, meaning that it could not be removed by conventional methods, such as dry process. A series of laboratory experiments under varying conditions such as time and agents and aeration quantity tests showed that a qualified product whose LOI (Loss On Ignition) was 3% can be obtained by using a flotation cell, but with a high ash concentration and a low tailings yield. However, under the same conditions, a better result was obtained by using a flotation column whose flotation improvement index was 7% higher than the flotation cell's. This showed that the use of column flotation for fly-ash decarburization was more efficient and more competitive than the use of a flotation cell. The second part of the field test of column flotation industry experiments investigated the effectiveness of different flotation agents and other experimental conditions. We concluded that the industrial product meet the standards for use as an ingredient in cement, and the carbon collected from the fly-ash can be re-burned in power plants.

High-efficiency fly-ash decarburization process by flotation

248th National Meeting (2014)

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