NAERINGSPH-Nærings-phd

Elkem Foundry Products is a leading metal treatment solution provider to the cast iron industry and supplier of high quality special ferrosilicon (FeSi) to the steel industry, with applications in the automotive and pipe industries to general engineering. Production of these alloys can be simplified by relating it to an everyday process, baking. A specified amount of ingredients (silicon oxide as quartz, iron in the form of an oxide, scrap metal etc. and a carbon source such as coal) is mixed, and heated in an electric arc furnace to the right temperature for a certain period. The process product in the form of various FeSi grades is tapped from the furnace, refined, solidified, crushed and then sold. Silicon (Si) production process is well known and has been studied in numerous research projects. Less research work focused on the FeSi process. The main difference between the two arise from the behaviour of chemical species in different environments. In pure form, oxides and elements have a set of specified properties. However, when mixed, their properties can be altered drastically leading to a complicated process. By downscaling the industrial furnace into relatively small experimental setups, the physical and chemical phenomena taking place during the production process can be investigated. The effect of different raw materials, holding times and temperatures can be studied. It was found that iron in the system facilitates the production of silicon, leading to a total decrease in the energy consumption. During excavations of Si/FeSi furnaces, a cavity surrounding the electrode tip was found. Experimentally, the cavity appears to be a result of SiO(g) condensation. Theses condensates act as a binder, preventing the charge above from sinking. Consumption of charge material below this zone will lead to a cavity. In addition, the choice of iron and carbon containing materials can influence cavity formation by affecting SiO(g) generating reactions.The PhD candidate is writing his thesis.

Elkem Foundry Products is a leading metal treatment solution provider to the cast iron industry and a supplier of high quality special ferrosilicons to the steel industry. The car industry, pipe producers and engine engineering companies are important customer categories. Ferrosilicon alloys are produced in large electrical furnaces with up to 50 MW of electric power. It is an important focus area for Elkem to develop more energy-efficient production, exploit raw materials in the best possible way, and reduce emissions from the production. To achieve this, it is necessary with a new and improved process understanding for the ferrosilicon process. Ferrosilicon alloys (FeSi) are produced with different amounts of iron in the raw materials depending on which alloy to be produced. Examples of are FeSi 75, FeSi 65, FeSi 55 and FeSi 50, where numbers denote the weight percentages of silicon. The production process for silicon is well known, and the various chemical reaction patterns and process phenomena in a silicon furnace has been studied in numerous research projects over several years. However, less basic research work has focused on the FeSi process. It has been assumed that the models for the (pure) silicon process could be applied on the FeSi process. This has been possible for the FeSi 75 process with some modifications, but the models are not valid for alloys with lower silicon amount. The increasing market for cast iron alloys requires FeSi 65/55/50, and it is therefore important to develop new knowledge about these processes. The research work will first be carried out in the laboratory scale and mathematical modeling at NTNU. Then, it is planned that the results should be verified by pilot tests at Elkem AS, Technology and possible by full-scale test campaigns at industrial FeSi furnaces.