Ökologische Bewertung des Recyclings von Mineralwolleabfällen als Ersatzrohstoffe und Zumahlstoffe in der Zementindustrie

Research output: ThesisMaster's Thesis

Authors

Abstract

In this master´s thesis, a life cycle assessment is carried out on cement production in which mineral wool waste is introduced into the manufacturing process as recyclate. Due to many possible places of introduction of mineral wool waste into the process, four scenarios are chosen and these are compared and contrasted with each other in terms of their environmental impacts calculated through the life cycle assessment. The first scenario considers the use of the mineral wool before clinker firing, with a substitution of the raw materials limestone and clay. In scenario 2.1, the mineral wool is introduced into the cement grinding process and replaces the granulated blast furnace slag. Another consideration in cement grinding is based on the substitution of the clinker by mineral wool waste (Scenario 2.2).The last scenario deals with the status quo of cement production and serves as a reference process. The declared unit comprises one ton of produced cement of cement group CEM II (Portland-composite cement) according to EN 197-1. The comparability of the scenarios is ensured by defined boundary conditions. The best result was achieved in Scenario 2.2, where mineral wool waste was introduced into the cement grinding process. This step reduced the amount of clinker per ton of cement. This resulted in a lower demand for raw materials, energy sources and electrical energy. This resulted in lower emissions during clinker production in the rotary kiln. By substituting the clinker in the grinding process and by keeping the amount of granulated blast furnace slag constant it was possible to increase the amount of secondary materials used compared with the status quo. The use of a landfill was also avoided in this scenario. All the factors mentioned resulted in a positive impact on the life cycle assessment. Due to the large CO2 emissions from the cement manufacturing process, the global warming potential has a high priority in the cement industry. If this potential is considered for the substitution of the clinker, a reduction of 7.5 % could be achieved. Thus, 42 kg less CO2 per ton of cement was emitted compared to the status quo. The result of this master`s thesis showed that scenario 2.2 is to be recommended with regard to environmental impacts for the cement industry and that the status quo is in all considered impact categories the worst option.

Details

Translated title of the contributionEcological evaluation of the recycling of mineral wool waste as substitute raw materials and additives in the cement industry
Original languageGerman
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Publication statusPublished - 1800