Possibilities of Zn Recovery from Waste Incineration Fly Ashes.

Modern economy is characterized by unprecedented increase in the consumption of raw materials and products. Heavy metals represent only 10% of all inorganic goods consumed, but due to their specific physical and chemical properties they are extremely important in everyday life. Zinc is the world's 4th most widely used metal. Due to the reduction of easily accessible natural resources and the growing shortage ofZn, it is necessary to find secondary raw materials and methods to recover metal from them. Fly ash from municipal solid waste incinerators (MSWI) is a suitable raw material for Zn recovery, because of the production quantity and the same content of Zn as in poor ore. Thereby, this paper is aimed to the recovery of Zn from fly ash on the real scale from data obtained from MSWI in the Czech Republic. Verification of the possibility of Zn recovery from fly ash through acid extraction with flue gas treatment system scrubber liquid has been carried out. The results were compared with the published results of Zn recovery using the Swiss technology FLUWA/FLUREC and the Swedish HALOSEP. The average efficiency of Zn extraction in the real MSWI is close to 60%, which is comparable to the efficiency of the technologies mentioned above. Other benefits of acid extraction are above all the neutralization of two hazardous waste streams from the MSWI (fly ash and scrubber liquid), the reduction of chemicals consumption and the total costs for treatment of fly ash and scrubber liquid, production of stabilized inorganic residues and shifting the process in the waste management hierarchy from landfilling towards metals recovery