Abstract
Two processes relating to the preparation section of recycled glass are described with reference to the complete process of manufacturing of foamglass granulates and to their application. The first process consists of crushing the glass from differentiated collection, with simultaneous separation of the extraneous elements mainly consisting of: plastic, aluminium, steel and cork. Implementation of this operation is performed with the Ehinger MUD patented crusher that is able to distinguish the grinding ability of the glass from that of other substances resulting in the fragmentation of the glass and not that of foreign bodies. It is interesting to note that during this operation, substantial frictional forces develop that are useful to reduce and to almost always remove the physical link that exists between glass and other materials. The second process described is that of final refining of the glass which is performed with an Ehinger Impianti vertical axis centrifugal ball mill named RM with a 15 % energy saving compared to traditional ball systems. [1] Recycling is efficient and sustainable, saves energy and natural resources. One kilogram of recycled glass replaces 1.2 kg of virgin raw materials. Therefore glass recycling reduces CO2 emissions and the demand for natural raw materials. This helps prevent the exploitation of natural resources. Due to technical reasons during the recycling process, a certain amount of glass cannot be recycled by the glass industry to manufacture new products. Poraver® utilizes this cullet and closes a gap in the recycling process. The production of expanded glass starts with ultra-fine grinding of the recycling glass. The preparation of the recycled glass and the fine grinding are crucial to the quality of the foamglass. Glass flower, binder and foaming agent are mixed and moulded into granules. After this the grain is sintered and foamed (expanded) in a rotary kiln. The result is a new product that is used as a raw material for high-quality building materials and industrial products. Expanded glass is used in dry mortar, panels and lightweight concrete as functional lightweight aggregate in construction chemical products and mineral casting. Future applications are becoming evident in the automotive sector and are magnetisable designed in biotechnology as a growth substrate for immobilizing micro-organ.
