Cilj ovog rada je izdvajanje cinka iz elektropećne prašine postupkom alkalne ekstrakcije pomoću jake natrijeve lužine te korištenje visokog neutralizacijskog/koagulacijskog učinka preostalog alkalnog krutog ostatka za obradu kiselih industrijskih otpadnih voda. Ispitana je i mogućnost regeneracije otpadnog mulja postupkom alkalne ekstrakcije cinka te primjene preostalog krutog ostatka za obradu kiselih otpadnih voda. U tu svrhu je korišteno sedam kompozitnih uzoraka elektropećne prašine iz Siskačke čeličane s udjelom cinka u rasponu od 5,71% do 28,18%. Alkalnom ekstrakcijom izdvojeno je između 62,4 i 84,6% cinka a sastav eluata preostalog krutog ostatka je zadovoljavao uvjete za odlaganje na odlagalište inertnog otpada. Njegovom primjenom za obradu otpadnih voda od pocinčavanja pri optimalnim uvjetima (pH = 8; tkon. = 20 min.) je uklonjeno između 99,17% i 100% teških metala čime su postignute vrijednosti koncentracija elemenata pogodne za ispust u okoliš. Otpadni mulj je regeneriran izdvajanjem cinka postupkom alkalne ekstrakcije a preostali kruti ostatak ponovo uspješno primjenjen za pročiščavanje kiselih otpadnih voda sa sličnom učinkovitosti uklanjanja kao i u prethodnom eksperimentu..; The objective of our work was to isolate zinc from electric arc furnace dust using the procedure of alkaline extraction with strong sodium hydroxide base and high neutralization/coagulation effect of the remaining alkaline solid residue for treating acidic industrial wastewater. The possibility of sludge regeneration was also tested using the procedure of alkaline zinc extraction and the application of the remaining solid residue for treating acidic wastewater. To this end, seven samples of composite electric arc furnace dust from the Sisak steel mill with zinc content ranging from 5.71% to 28.18% were used. By means of alkaline extraction, between 62.4 and 84.6% zinc was isolated. The composition of eluate from the remaining solid residue met the criteria for disposal at inert waste disposal sites. Its use in treating wastewater from the galvanizing process in optimal conditions (pH = 8; tcon = 20 min.) removed between 99.17% and 100% of heavy metals, thus achieving the concentration values of elements suitable for discharge into the environment. The sludge was regenerated by zinc isolation using alkaline extraction while the remaining solid residue was successfully reused for treating acidic wastewater with a similar removal efficiency as in the previous experiment.