Investigation of the possibility of the reutilization of some industrial wastes

Abstract

The utilization of nitrogypsum and bottom ash, wastes from the factory "Milan Blagojević" (Lučani–Serbia), was investigated. For this purpose, mixtures composed of calcined nitrogypsum (CaSO4. 0,5H2O), ash (mass ratio 1:1) and water (water/solid mass ratio 0.5), as well as similar mixtures consisting of 1.0 mass%5.0 mass%10.0mass%of lime (CaO) with the same gypsum/ash and water/solid mass ratios, were prepared. These mixtures gave solidified products at room temperature and atmospheric pressure, which after 28 days had satisfactory compressive strengths for application in the civil industry. The product with 5.0mass%of added lime has the best mechanical characeristics. X-ray and qualitative IR analysis showed that this product mainly consisted of calcium sulphate dihydrate (CaSO4.2H2O) and carbonates, as well as a small quantity of ettringite (3CaO.Al2O3.3CaSO4.32H2O).

Keywords

• fly ash
• nitrogypsum
• ettringite
• fal-g binder