Mikrokalorimetrijsko istraživanje hidratacije gipsa

master's thesis

• Title (english): Microcalorimetric study of gypsum hydration
• Author: Biljana Šandor
• Mentor: Nevenka Vrbos (mentor)
• Committee member: Nevenka Vrbos (predsjednik povjerenstva)
• Committee member: Juraj Šipušić (član povjerenstva)
• Committee member: Emi Govorčin Bajsić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2017-02-28, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Analysis, Synthesis and Management of Chemical Processes

Abstract

Istražena je dehidratacija otpadnog gipsa s ciljem njegove oporabe tj. recikliranja. Uzorci otpadnog gipsa iz tvornice TONDACH d.o.o. iz Đakova, obrađeni su u hidrotermalnom reaktoru na temperaturama od 150, 160, 170, 180 i 190 °C tijekom 24 h (zatvoreni i otvoreni sustav). Pripravljeni uzorci pokazuju gubitak mase u skladu s reakcijom djelomične ili potpune dehidratacije CaSO4×2H2O. Morfologija nastalog produkta određena je elektronskom mikroskopijom, te uzorci pripravljeni pod niskim tlakom pokazuju gotovo neizmijenjenu morfologiju (izduženi kristali), dok dehidratacijom pri povišenom tlaku nastaju kristali manjeg omjera duljine prema širini. Rendgenskom difrakcijskom analizom određen je fazni sastav produkta, te je ustanovljeno da dolazi do nestanka dihidrata, CaSO4×2H2O i nastanka hemihidrata, CaSO4×1/2H2O i anhidrita. Rezultati mikrokalorimetrijskog određivanja topline hidratacije u skladu su s rezultatima kvalitativne rendgenske difrakcije i pokazuju trend pada ukupne topline hidratacije s porastom temperature termičke aktivacije.

Abstract (english)

In this paper we studied dehydration of gypsum waste with goal of its recycling. Samples of gypsum waste was from Tondach d.o.o. factory from Đakovo, they were processed in hydrothermal reactor at temperatures 150, 160, 170, 180, 190 °C during 24 h (open and closed system). Prepared samples show a weight loss in accordance with the reaction of partial or complete dehydration of CaSO4×2H2O. Morphology of the resulting product was determined with electron microscopy, and samples prepared under low pressure showed almost unchanged morphology (elongated crystals), while in dehydration under high pressure occur crystals a smaller ratio of length to width. With analyzing X-ray diffraction it was determined phase composition of product, and it was established occurring of dehydrates CaSO4×2H2O, hemihydrates CaSO4×1/2H2O, and anhydrites. Results of micro calorimetric determination of hydration heat are matching with results of qualitatively X-ray diffraction, and they are showing decreasing trend of hydration heat withincrease of temperature thermal activation.

• Keywords: otpadni gips; termička obrada; toplina hidratacije
• Keywords (english): gypsum waste; thermal treatment; hydration heat
• Language: croatian
• URN:NBN: urn:nbn:hr:149:733999
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-11-26 12:13:37