Citation: Kragovi´ c, M.; Stojmenovi´ c, M.; Risti´ c, N.; Mili´ cevi´ c, S.; Živkovi´ c, S.; Liu, S.; Gulicovski, J. Application of the Hazardous Waste Vitreous Enamel Generated in the Production Process of Heating Devices as a Partial Replacement for Cement. Buildings 2022, 12, 1287. https:// doi.org/10.3390/buildings12081287 Academic Editor: Rita Bento Received: 21 July 2022 Accepted: 17 August 2022 Published: 22 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). buildings Article Application of the Hazardous Waste Vitreous Enamel Generated in the Production Process of Heating Devices as a Partial Replacement for Cement Milan Kragovi´ c 1, * , Marija Stojmenovi´ c 1 , Nenad Risti´ c 2 , Sonja Mili´ cevi´ c 3 , Sanja Živkovi´ c 1 , Shanke Liu 4 and Jelena Gulicovski 1 1 “Vinˇ ca” Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 11351 Belgrade, Serbia 2 Faculty of Civil Engineering and Architecture, University of Niš, Aleksandra Medvedeva 14, 18106 Niš, Serbia 3 Institute for Technology of Nuclear and Other Mineral Raw Materials, Franše d’Eperea 86, 11000 Belgrade, Serbia 4 Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China * Correspondence: m.kragovic@vin.bg.ac.rs Abstract: Solving problems with hazardous waste materials is of crucial importance today. In the presented study, the application of waste vitreous enamel as a cement replacement up to 30% in mortar and concrete production was investigated. The chemical and physical-chemical characterization of the starting material was performed, as well as a leaching test and physical-mechanical characterization of mortar and concrete mixes. Obtained results showed that, due to its chemical composition, the vitreous enamel used must be classified as hazardous waste. At the same time, it possesses pozzolanic properties and satisfies minimal criteria for use as a cement replacement. Testing mortars and concrete mixes indicate that waste vitreous enamel can be applied as a construction material for cement replacement in the maximal amount of 20%. The leaching test was performed in accordance with international standard EN 12457-2 on hardened mortar with a maximal cement replacement of 20%. The results showed that there was no significant release of toxic elements, i.e., that the practical application of hazardous waste vitreous enamel in the construction industry may be fully in line with environmental standards. Keywords: hazardous waste; vitreous enamel; mortar; concrete; cement replacement; building industry 1. Introduction The rapid development of industry as well as a constant need for new and more advanced products has resulted in the generation of large quantities of waste, and its quantities can be measured in millions and billions of tons. Depending on the country, such waste is disposed of at legal (commonly in developed and middle developed countries) and/or insufficiently secured illegal landfills (mainly characteristic of underdeveloped countries where it has a great negative impact on the environment and human health). Depending on the nature of the waste, its properties, and its origin, different methods of disposal are used, i.e., different types of secured landfills, such as open, controlled, and closed. In order to avoid problems of treatment and disposal, it is necessary to work on the requests for the input of technology on waste minimization [1–4]. In the case of non-hazardous waste, it can be returned to the production process using appropriate technologies with reasonable investments, which is followed with low-cost production of end products, so that, besides environmental gains, economic benefits may be achieved, too. The environmental benefits are visible in the removal of the waste from the environment as well as by reducing consumption of natural resources. This is the practice in almost all Buildings 2022, 12, 1287. https://doi.org/10.3390/buildings12081287 https://www.mdpi.com/journal/buildings