Affiliation:
1. University of Belgrade, Faculty of Mining and Geology, Belgrade, Serbia and Montenegro
Abstract
The possibility of obtaining ? - anhydrite from nitrogypsum, which is waste from a nitrocellulose plant, was investigated. It was shown by means of qualitative IR analysis that the product obtained by heating nitrogypsum for 5 hours at 700 o C was ? - anhydrite. When the ?- anhydrite was mixed with water at a W/S (water/solid) ratio of 0.54 in presence of different accelerators (CaO, mixture CaO - ash, ash, Na2SO4 and K2SO4), pastes were formed which hardened on standing. The compressive strength of the hardened samples was measured after 7 and 28 days and their composition determined by qualitative IR analysis. On the basis of these results, it was observed that a relationship exists between the composition (depending on the used accelerator) and the compression strength of the samples. Namely, the formation of large cores of double salts: syngenite (K2SO4 ?CaSO4 ?H2O) and glauberite (Na2SO4 ?CaSO4), in the presence of the accelerators K2SO4 and Na2SO4, respectively, was due to the rapid and complete crystallization of the dihydrate (CaSO4 ?2H2O). This fast crystal growth of the dihydrate resulted in high compressive strengths of these samples. In the other samples (prepared in presence of the accelerators: CaO, mixture CaO - ash and ash), dihydrate did not form and, consequently, their compressive strength was low.
Publisher
National Library of Serbia
Subject
Materials Chemistry,Metals and Alloys,Mechanics of Materials,Geotechnical Engineering and Engineering Geology
Cited by
5 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献