Abstract
In view of the limited reactivity of crystalline silica used in the production of ferrosilicon, it is necessary to search for silica-containing raw materials that have this property to a higher degree. The article presents the results of studies on the production of ferrosilicon from a mixture of amorphous silica-containing rocks – opoka and diatomite in a 1:1 ratio in the presence of coke and steel shavings. The studies have included the electric smelting of the charge in a single-electrode arc furnace and using the second-order rotatable designs of experiments (Box-Hunter plans) followed by graphical optimization. The research has established that FeSi25 (24.5-30% of Si), FeSi45 (41-47% of Si), and FeSi50 (47-51% of Si) grades of ferrosilicon can be smelted from a mixture of diatomite and opoka, depending on the amount of coke and steel shavings. The optimal parameters for producing FeSi25 ferrosilicon (with the extraction of 80-82.4% of silicon into the alloy) were 35.0-37.2% of coke and 33.75-35.0% of steel shavings. FeSi45 ferrosilicon (with extraction of 80-84.6% of silicon) was formed with 38.0-45.0% of coke and 29.2-33.2% of steel shavings. At 40.4-45.0% of coke and 29.2-31.1% of steel shavings, FeSi50 ferrosilicon was formed; the extraction of silicon into the resulting alloy was more than 80-81.5%. At the balance electric smelting of the diatomite and opoka mixture in the presence of 45% of coke and 30% of steel shavings, ferrosilicon of FeSi50 grade (51.8-52.6% of Si) was produced with the 82% silicon extraction degree.