Floatation separation apparatus, method of floatation separation, and method of manufacturing products using the same

A floatation separation apparatus, comprising:

• a treatment tank main body having a downward narrowing bottom portion, a tank main body circulation outlet and a tank main body circulation inlet, the treatment tank storing a liquid to be treated in which particles of fly ash including unburnt carbon are dispersed;
• a froth overflow means installed in an upper portion of the treatment tank main body;
• a circulating means for taking out the liquid to be treated from the outlet for circulation and for returning the liquid to the downwardly narrowing bottom portion, thereby circulating the liquid to be treated, and for returning the liquid in the circulation means through said circulation inlet along the internal peripheral surface of the downward narrowing bottom portion, and for forming a vortex flow within the treatment tank main body;
• and
• a foaming device for supplying air bubbles into the circulation liquid between the circulation inlet and circulation outlet,
• wherein the outlet for circulation is installed into the upper portion of the main tank body and below said froth overflow means,
• wherein by forming the vortex flow by the circulating means while supplying the air bubbles to the circulated liquid by the foaming device, the unburnt carbon contained in the fly ash particles is made to attach to the air bubbles within the treatment tank main body and goes up to a liquid surface at said upper end portion of the tank main body as froths, due to difference in surface wettability between the unburnt carbon and the fly ash in the treatment tank main body.