magistrsko delo
Natalija Orešek (Author), Franc Zupanič (Mentor), Niko Samec (Co-mentor)

Abstract

Pri sežigu komunalnih odpadkov nastajajo večje količine produktov, ki jih moramo ustrezno zajeti in obdelati do te stopnje, da ne bodo negativno vplivali na okolje in ljudi. Med temi produkti sta zelo pomembna pepel iz kotla in iz odpraševalnih naprav (leteči pepel). Vsebujeta namreč velike količine težkih kovin in nevarnih kemikalij, (As, Pb, Sb, Sn, Sr, Cd, Cr, Cu, Hg), pa tudi sledi organskih polutantov (poliklordibenzo-dioksini in furani), zato imata lastnosti nevarnega odpadka. Teh odpadkov ni mogoče odlagati v okolje ali jih koristno in varno za okolje in ljudi uporabiti za druge uporabne produkte brez stabilizacije ali celo inertizacije. Kemijska sestava in fizikalne lastnosti letečega pepela so odvisne predvsem od sestave vhodnega materiala - torej od komunalnih odpadkov, ki pa variira in se spreminja v odvisnosti od sezone in sestave odpada. V splošnem pa leteči pepel vsebuje SiO2, Al2O3, CaO in spremenljive količine MgO, Na2O, K2O, žveplo (kot SO3),. - podobne sestavine, kot se uporabljajo v steklarski industriji za pripravo stekla - zato je bil osnovni cilj magistrske naloge preveriti zmožnost visokotemperaturnega taljenja letečega pepela sežigalnice v Augsburgu, Nemčija in iz prašnega pepela izdelati kompaktne masivne dele po treh različnih postopkih (taljenje + naknadna kristalizacija vzorca; taljenje + mletje materiala + stiskanje + sintranje vzorca in stiskanje + sintranje vzorca). Pri taljenju se tvori steklu podobna, amorfna snov; leteči pepel se zatali, postane steklast oz. se vitrificira. Če nastalo steklo naknadno toplotno obdelamo - z namenom pridobitve boljše kemijske obstojnosti in višje tlačne trdnosti - nastalo steklo kristalizira (se razstekli oz. devitrificira), nastane steklokeramika. Raziskane so bile relacije in odvisnosti med temperaturo taljenja letečega pepela, tlaka, s katerim stisnemovzorec pred sintranjem in temperaturo toplotne obdelave dobljenega produkta, z namenom pridobiti produkt z najoptimalnejšimi lastnostmi. Na podlagi meritev različnih fizikalnih in kemijskih lastnosti izdelanih vzorcev smo ugotavljali, po kateri od teh tehnologij lahko iz prašnega letečega pepela izdelamo kompaktne dele s primerno trdnostjo in kemijsko obstojnostjo, kar bi omogočilo njihovo varno in neškodljivo odstranjevanje oziroma uporabo vpraktične namene (kot npr. nasipni material oz. kot material za tlakovanje).

Keywords

sežig komunalnih odpadkov;termična obdelava;preostanki po sežigu;leteči pepel;taljenje;zasteklitev;vitrifikacija;steklo;toplotna obdelava;sintranje;steklokeramika;

Data

Language: Slovenian
Year of publishing:
Source: Maribor
Typology: 2.09 - Master's Thesis
Organization: UM FS - Faculty of Mechanical Engineering
Publisher: [N. Orešek]
UDC: 628.477:666.1.038(043.2)
COBISS: 13552662 Link will open in a new window
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Other data

Secondary language: English
Secondary title: Thermal treatment of municipal solid waste incinerator fly ash
Secondary abstract: During the incineration of municipal waste, large amounts of residues are formed. They have to be safely disposed due to serious environmental impact on people and animals. Among these residues, electrostatic fly ash and boiler ash have the same composition - they contain large amounts of heavy metals and undesired elements (As, Pb, Sb, Sn, Sr, Cd, Cr, Cu, Hg) as well as traces of organic pollutants (polychlordibenzo-dioxins and furans). Because of high environmental standards and strict regulations in force fly ash is considered to be a dangerous waste and should consequently be landfilled under strict conditions or in dormant chambers as fillers. Chemical composition and physical properties of the fly ash depend mainly from the composition of the input waste which is variable and dependable from the season and composition of the waste material. Main components of the fly ash are SiO2, Al2O3, CaO and variable amounts of MgO, Na2O, K2O, sulphur (as SO3),. - same components as in the glass industry for making glass - thats why an ability of fly ash from incineration plant in Augsburg, Deutschland for thermal treatment was applied. Massive, glassy-like amorphus product was formed, fly ash melts itself and it becomes glassy (vitrified). If this produced glass is subsequently heat treated - in order to get better chemical resistivity and higher compressive strenth - glass crystallizes (is devitrified), and the glass-ceramics is formed. Three different methods for thermal and heat treatment of fly ash were applied (melting + crystallization, melting + grinding + pressing + sintering and pressing + sintering) in order to obtain product with the most optimal properties. Relations between temperature of the melting, temperature of heat treatment and pressure were analysed and discussed. Main purpose of this master thesis was considering the ability of producing compact solid massive parts from dusty fly ash under three different processes and on the ground of measuring different physical and chemical properties of produced material select the best technology for producing the material, that is chemicaly durable and compressive strengthened for safe and harmfull landfilling or use as a material in practical way (as a gravel material or as a pavement).
Secondary keywords: incineration;solid waste incinerator residues;fly ash;thermal treatment;ash melting;vitrification;glass;heat treatment;sintering;glass ceramics;
URN: URN:SI:UM:
Type (COBISS): Master's thesis
Thesis comment: Univ. v Mariboru, Fak. za strojništvo
Pages: XIII, 88 f.
Keywords (UDC): applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;engineering;technology in general;inženirstvo;tehnologija na splošno;public health engineering;water;sanitation;illuminating engineering;sanitarna tehnika;zdravstvena tehnika;voda;sanitarne naprave;svetlobna tehnika;urban hygiene;wastes;refuse;rubbish;garbage;collection and disposal of town wastes;komunalna higiena;applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;chemical technology;chemical and related industries;kemijska tehnologija;kemijske in sorodne industrije;glass industry;ceramics;cement and concrete;industrija stekla;keramika;cement in beton;glass industry;glass technology;glass manufacture in general;glass in the comprehensive sense;industrija stekla;tehnologija stekla;izdelava stekla na splošno;steklo v širšem pomenu;
ID: 988121