Process and apparatus for treating fly ashes by floatation

摘要

Treatment of fly ashes by floatation for separating off carbon particles and subsequent dewatering is still accompanied in many cases by considerable difficulties. This is principally due to the fact that the carbon-containing particles present in the fly ash have a relatively high specific surface area with many pores and the floatation reagents adhere with difficulty to the surfaces. Removal of the carbon particles from the fly ash by floatation is thus very small and in many cases uneconomical. However, according to the invention a sharp separation of the carbon particles from the accompanying materials and thus a particularly economical removal by floatation of the carbon particles present in the fly ash is achieved by the coarse fraction arising in the classification of the fly ash being subjected to a separation into high-carbon and low-carbon fractions, and by the fine fraction arising in the classification being conditioned and then, with added floatation reagents, being subjected to a stirrer-free pneumatic floatation. <IMAGE>