Greenhouses gases from the process of aluminium production and the possibilities of their reduction

U ovom radu prikazan je pregled emisija stakleničkih plinova koji nastaju proizvodnjom primarnog aluminija te potencijalne mogućnosti za njihovo smanjenje. Staklenički plinovi imaju veliki utjecaj na zdravlje ljudi i cjelokupni okoliš te im se iz tog razloga posvećuje velika pažnja. Uz emisije stakleničkih plinova ugljikovog (IV) oksida (CO2) i perfluorougljika, PFC (CF4, C2F6) za vrijeme proizvodnje primarnog aluminija nastaju druge onečišćujuće tvari poput crvenog mulja, prašine te plinova, kao što su fluoridi, sumporovi, dušikovi oksidi i mnogi drugi. Najveće količine emisija stakleničkih plinova nastaju prilikom elektrolitičke redukcije glinice što uvelike ovisi o vrsti tehnologije koja se upotrebljava. Tehnologije se dijele s obzirom na vrstu anode koja se upotrebljava kao i prema načinu na koji se glinica dodaje u ćeliju. Primarna emisija koja nastaje prilikom elektrolitičke redukcije je CO2, nakon čega slijede emisije PFC. Emisije CO2 nastaju kao posljedica potrošnje ugljičnih anoda te kao posljedica reakcije između ugljičnih anoda, glinice i taline kriolita za vrijeme elektrolitičke redukcije. Emisije PFC nastaju kao posljedica poremećaja u radu elektrolitičke ćelije (tzv. anodni efekt). Prilikom rada elektrolitičke ćelije u normalnim uvjetima emisije, PFC se emitiraju u nemjerljivim količinama. Kako bi se količine spomenutih emisija mogle smanjiti upotrebljavaju se neke od mogućnosti smanjenja stakleničkih plinova, kao i kontrola njihovog ispuštanja.This paper gives an overview of green-house emissions created during the production of primary aluminium and different possibilities of their reduction. Greenhouses gasses have a major impact on human health and the environment and therefore deserve great attention. In addition to the greenhouse gas emissions of carbon (IV) oxide (CO2) and perfluorocarbon ,PFC (CF4, C2F6), other pollutants such as red mud, dust and gases, such as fluorides, sulfur, nitrogen oxides and many others, are produced during the production of primary aluminum. During the process of electrolytic reduction of alumina largest amount of greenhouse gases are released, which depends on the technology being used. The technologies available can be divided based on the type of anode used in the process, as well as the method of adding alumina to the reaction cell. The primary emission during electrolytic reduction is CO2, after which perfluorocarbons follow. CO2 emissions are a product of carbon anodes consumption and a consequence of reactions between the anodes, alumina and cryolite melt during the electrolytic reduction. PFC emissions are a product of disturbances in the operation of electrolytic cell, the so-called anode effect. During normal workflow amount of perfluorocarbon are released in non-traceable amounts. In order to reduce the amounts of the aforementioned emissions, some of the possibilities of reducing greenhouse gases, as well as the control of their discharge, are used