ABSTRACT
Glass is a recyclable material, and in a country of about 120 million people with increasing urbanization, industrialization and standards of living, it is necessary that resources are continuously sourced and managed for sustainable development. In Nigeria today, the populace are yet to be aware of waste glass recycling let alone making sure that the waste glass they generate should be contaminate free, therefore most glass wastes that would be collected from neibourhoods would be expected to be contaminated and such material even though cannot be used for making containers, they can be directed to lower valued uses, such as road aggregate or glassphalt. There are different processes for the utilization of cullets for manufacture of new glass. These processes include remelting and sintering. cullets can be used as crushed to be remelted in pots or furnaces for use to make new products or sintered which involves the use of powders. This study sought to convert the glass waste of Light tubes and window glass (soda- lime silica glass), drinking glass (lead crystal glass) and laboratory glass (borosilicate glass) to functional forms using the sintering method. The glass samples were analyzed using the ICP technique to determine their chemical composition. Two different grain sizes comprising of 106 micrometre mesh and -75 micrometre were taken from each sample to produce the powder compacts with the hope of achieving better compaction and more full density on fusion. 10g was weighed each time of every sample and pressed using uniaxial press, forming three sets of compacts. The first containing no binder pressed at 5,000 psi and 10,000 psi, the second set contained binder pressed at 5000 psi and the third set contained binder and also pressed at 10,000 psi. 29mm (1.15") diameter and 10 mm of maximum thickness compacts were made. The samples were fired in an electric kiln at the sintering temperature range of 700 - 750, with holding time of two hours. The drying and firing shrinkages were measured according to the ASTM C 326, weight, size, warpage, absorption and compressive stress were determined according to ASTM C 67. Additional imperviousness test for glazed ceramic facing tile as specified in specification C126 was also carried out on some of the samples. The microstructures of specimens were observed using a JEOL JSM 820 Scanning Electron Microscope (SEM). Sintering temperature range of 700-750oC was found suitable for composites containing bentonite as binder. The samples sintered at 750oC were very hard and they developed a thin layer of glazing, making it possible to produce a glazed tile all in one process.