Recovery of coke fines from fly ash by air sparged hydrocyclone flotation

Fly ash from a power plant in Gdansk, Poland is stockpiled at two dump site s and contains an average of 15 wt% combustible residue, in the form of ver y fine coke particles. If recovered, the coke could serve as environmentall y friendly fuel or as a source of carbon-derived materials, and the ash cou ld be utilized in the production of construction materials. Since the fly a sh material is already wet, a flotation technique was proposed for separati on and product recovery. The flotation tests were carried out in a 1-1 Denv er-type flotation cell and in a 2 inch diameter air-sparged hydrocyclone (A SH). The flotation concentrate from the air-sparged hydrocyclone contained 35% coke by weight on a dry basis, with a coke recovery to the concentrate of 54%. Experimental results are discussed with respect to particle charact eristics. (C) 1998 Elsevier Science Ltd. All rights reserved.