Recycle the slag waste of metallic magnesium production process

Sustainability is how all the system in the world remain diverse and productive. In more general terms, sustainability is the endurance of systems and processes. The organizing principle for sustainability is sustainable development, which includes the four interconnected domains: ecology, economics, politics and culture. Sustainable development is the organizing principle for sustaining finite resources necessary to provide for the needs of future generations of life on the planet. It is a process that envisions a desirable future state for human societies in which living conditions and resource-use continue to meet human needs without undermining the "integrity, stability and beauty" of natural biotic systems The 2005 World Summit on Social Development identified sustainable development goals, such as economic development, social development and environmental protection. This view has been expressed as an illustration using three overlapping ellipses indicating that the three pillars of sustainability are not mutually exclusive and can be mutually reinforcing. While the United Nations Millennium Declaration identified principles and treaties on sustainable development, including economic development, social development and environmental protection it continued using three domains: economics, environment and social sustainability. More recently, using a systematic domain model that responds to the debates over the last decade, the Circles of Sustainability approach distinguished four domains of economic, ecological, political and cultural sustainability. This is in accord with the United Nations Agenda 21, which specifies culture as the fourth domain of sustainable development. Generally sustainable development consists of balancing local and global efforts to meet basic human needs without destroying or degrading the natural environment. The question then becomes how to represent the relationship between these needs and the environment. Rapid consumption of natural resources for the purpose of maintenance of modern life, destruction of nature, difficulty of disposal of wastes which are arising from environmental pollution and consumption, imposed people obligation to use resources as optimum. The society and industrial systems must begin to mimic nature and move from being primarily linear to being cyclical. Each material must be used as efficiently as possible and must be chosen so that it may either return safely to a cycle within the environment or remain viable in the industrial cycle. The vision of Zero Waste can be seen as a solution to these needs and a key to future. Zero solid waste, zero hazardous waste, zero toxic emissions, zero material waste, zero energy waste and zero waste of human resources will protect the environment and lead to a much more productive, efficient, and sustainable future. The use of an endpoint goal of "zero" recognizes that simple making small steps without a goal may not achieve a sustainable future while use of a clear defined goal will lead to more rapid innovative improvements. Waste Management relies on three principles according to European Union's approach. Main element of Waste Management strategy is to prevent waste. If there is less arising waste there will be less recyclable and/or landfill materials, this is the most important and the first step. Recovery is the second most important principle. The third principle is the treatment of the unrecoverable wastes in suitable conditions. EU's waste approach strategy is a sound business tool that, when integrated into business processes, provides an easy to understand stretch goal that can lead to innovative ways to identify, prevent and reduce wastes of all kinds. It strongly supports sustainability by protecting the environment, reducing costs and producing additional jobs in the management and handling of wastes back into the industrial cycle. In this thesis, researches are for the recycle of slag waste of Turkey's first Magnesium Plant which will be constructed in Eskisehir. The plant will be produced magnesium (%99,9 purity) from dolomite via pidgeon process. The Pidgeon process is one of the methods of magnesium metal production, via a silicothermic reduction. The Pidgeon process is a batch process in which finely powdered calcined dolomite and ferrosilicon are mixed, briquetted, and charged in retorts made of nickel-chrome-steel alloy. The hot reaction zone portion of the retort is gas fired in a furnace, while the condensing section equipped with removable baffles extends from the furnace and is water-cooled. Due to distillation, very high purity magnesium crowns are produced, which are remelted and cast into ingots. The mentioned plant will be produced roughly 154.500 tons of slag from the hot reaction zone (reduction and refining) annually. A trial production had been made by a similar plant with the raw material from Turkey in China. For this thesis the trial production's waste had been used as a slag source as, the Magnesium Plant was in the construction phase. The slag was analyzed chemically and physically in Esan and 2 university laboratories. According to the test results, slag was not hazardous. Detailed results are given in the thesis. In this study the usability of slag as an admixture material had been made in cement and building materials industry considering both its physical and chemical properties. There had been a test done at a private brick industry company's laboratory which included samples of slag. Calcium oxide and magnesium oxide in samples reacted with water within environment. In this reaction formed calcium hydroxide and magnesium hydroxide compounds. Moreover, there had been a huge increase on the volume of bricks with the reaction which had been disrupted the brick structure. Researchers have concluded that slag usage is not suitable for brick industries. On the other hand, there had been a test done at Istanbul Technical University Structural Materials Laboratory. Samples included slag as a substitution material for cement. Test methods of studies was conducted according to the TS-EN 196 series standards. For the cement industry, lots of tests had been carried out with the methods of testing cement (TS-EN 196 series) standards at Istanbul Technical University Structural Materials Laboratory. TS-EN 196-1 standard describes the method for the determination of the compressive and, optionally, the flexural strength of cement mortar. Furthermore, TS-EN 196-3+A1 standard specifies the methods for determining standard consistence, setting times and soundness of cements. All experiments were performed according to these standards. Test results had been evaluated from many perspectives. Consequently, slag (at a certain rate) could be used as a substitute for cement which are given detailed information in the thesis.