چكيده به لاتين
Foam glass is a porous insulation material that is used as a building material and for heat and sound insulation in the construction of buildings and petrochemical, oil and gas industries. In this study, the possibility of making foam glass with controlled porosity distribution, using calcium carbonate and dolomite as foaming agents from recycled sodium-calcium silicate glass (soda lime) was investigated. In these experiments, soda-lime glass powder with 1–12 %wt. of each foaming agent and 0.5 %wt. starch adhesive was mixed and cylindrical samples were made using a hydraulic cold press with a pressure of 15 Mpa. Due to the results of simultaneous differential thermal analysis (STA) and direct observations made in the furnace, the pressed samples were heated at foaming temperatures of 780, 750, and 730 °C and at different foaming times of 5, 15, and 30 minutes. The effect of type and amount of foaming agent and heat treatment conditions in terms of temperature and foaming time on porosity and its distribution, water absorption percentage, density, microstructure, crystalline phases, and compressive strength of the samples were investigated. By comparing the results, the optimal conditions selected and final products with the application of foam glass tile were fabricated and evaluated; foam glass with a gradient porosity distribution was made by pouring compounds with different amounts of foaming agents into each other in layers and applying a pressure of 15 MPa. At last, taking into account all the properties obtained from the final samples and paying more attention to lower bulk density and more uniform porosity distribution in the final samples, samples made of layered compositions of 0, 2, 4, and 5 %wt. carbonate calcium with 0.5 %wt. starch adhesive and cooked at foaming temperature of 730 °C for 30 minutes, with a bulk density of 0.63± 0.04 (g/cm3) and the same layer composition and heat treatment conditions for samples with dolomite foaming agent, with a bulk density of 0.69± 0.07 (g/cm3), were selected as the best samples of this study.
