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Approximate chemical composition of blast furnace slag following: SiO2-30-40%, CO -30-50% Al2O3 -4-20%, MnO-0 ,5-2%, FeO-0 ,1-2%, SO3 -0,4-2,5% basic slag can remove metal contaminants – sulfur, phosphorus, and therefore the main steel-making process is most common. The mineralogical composition of metallurgical slag characterized by the presence of compounds with a lower basicity than the minerals of Portland cement clinker: mellilit Ca2AlSiO7-Ca2Mg (Si2O7), larnite -Ca2SiO4, rankinite Ca3Si2O7, psevdovollastonit -CSiO3, anorthite Ca2Al2 (Si2O8), monticellite CMgSiO4, dioxide CMg (SiO3) 2. The ratio of those or other minerals is not only the chemical composition of slag, but the conditions of their cooling. For example, granulated slag consists mainly of glass and crystal inclusions larnite, mellilita. In slag dump is dominated by crystals larnite, rankinite, pseudowollastonite, mellilita, and of high-acid – anorthite at high contents of MgO – morvinita Ca3Mg (Si2O8), monticellite dioxide.

In the production of cast iron in cupola furnaces are produced mainly acidic wastes, ie silica-rich than the oxides of calcium and magnesium. Slow cooling in the acidic slags allocated minerals – pyroxenes, anorthite, melilite, ore minerals, they also present alyumokremnezemistoe glass. Non-ferrous slags are very diverse, their specific weight in comparison with steel slag, assuming unit smelted metal, much more. If the smelting of iron and steel formed 0.2 – 1 ton of slag per 1 ton of metal, the nickel smelter at his number is 150 tons, copper not less than 10-30 m. In addition to oxides of silicon, aluminum, calcium, magnesium, iron and manganese in the slag contains large amounts of valuable components such as copper, cobalt, zinc, lead, cadmium, and rare metals.

In connection with the specific composition of non-ferrous slag general perspective direction in addressing the problem of using them is the principle of complex processing, which includes three main stages: 1) pre-extraction of nonferrous and rare metals, and 2) release of iron, and 3) use silicate slag residue for production of building materials. However, in practice, most slag processing finishes first or second stage. By analogy with metallurgical slag as fuel can be classified into acidic, neutral and basic. Most fuel slag is classified as acidic or neutral. Slag deposits of domestic coal are mostly acidic. The main slag containing an increased amount of iron oxide and 40% CO slags are some of the brown coal and shale.