Processing and utilization of metallurgical slag

Metallurgy and foundry industry create a huge amount of slags that are by-products in production of pig iron, steel and cast iron. Slag is produced in a very large amount in pyrometallurgical processes, and is a huge source of waste if not properly recycled and utilized. With rapid growth of industrialization, land available for land-filling of large quantity of metallurgical slag is being reduced all over the world and disposal cost is becoming increasingly higher. Metallurgical slag from different metallurgical processes treated and utilized in different ways based on different slag characteristics. The most economic and efficient option for reducing metallurgical waste is through recycling, which is a significant contribution to saving natural resources and reducing CO2 emissions. Characteristic of slags as well as its treatment and utilization are given in the paper. Slag from pig iron and steel production is used most frequently in building industry. From experiments using blast furnace slag and granulated blast furnace slag as gravel, and water glass as binder it can be concluded that that the best results – the best values of compression strength and tensile strength were reached by using of 18% of water glass as a solidification activating agent. According to cubic compression strength, mixture from 50% blast furnace gravel, 50% granulated blast furnace slag and 18% water glass falls into C35/45 class of concrete. Such concrete also fulfils strength requirements for road concrete, moreover, it even exceeds them considerably and, therefore, it can find an application in construction of road communications or in production of concrete slabs