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| TECHNOLOGICAL ANALYSIS OF THE PROCESS OF METALS RECOVERY OF LARGE DUST FROM THE CONVERTER USING METALLURGICAL METHODS
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Toshpulatov D.D., Khojiev Sh.T., Berdiyarov B.T., Kholmominova S.F.
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Abstract:
In the converter shop, the main sources of environmental pollution are dust and gas emissions into the atmosphere. These high-temperature emissions are subdivided into organized ones, which include exhaust gases captured when leaving the converter neck, and unorganized, which are usually not captured and enter the workshop atmosphere. Unorganized emissions occur periodically - when pouring cast iron, loading scrap, draining metal and slag, rolling the converter, when knocking out gases through the gap between the neck and the entrance to the gas outlet tract; these emissions contain dust, heat and a number of harmful gases (in various cases, these are CO, oxides of nitrogen and sulfur, fluorides).Even greater pollution of the environment can be caused by gases leaving the converter due to their large amount and high dust content. These gases are products of carbon oxidation and, when blown from the top, contain 83-89% CO, 9-11% CO2, 2, 2; their temperature in the course of blowing increases from 1350 to 1700 °C. The gases contain fine dust - mainly iron oxides, which appear as a result of iron evaporation in the high-temperature under-tuyere zone and subsequent vapor oxidation; the amount of dust is 80-250 g/m3 of gas, in connection with which all converters are equipped with gas cleaning systems to reduce the dust content to acceptable sanitary standards (less than 0.1 g/m3)In this regard, all oxygen converters are equipped with an exhaust gas removal and purification system, which significantly complicates and increases the cost (by 10-20%) of the construction of a converter shop.The complexity and high cost of cleaning is associated with high temperature, a large amount of exhaust gases that changes during the purge. The approximate amount of exhaust gases can be determined taking into account the fact that they consist mainly of CO and when carbon is oxidized to CO, two molecules of CO are formed per molecule of oxygen. Therefore, the maximum amount of exhaust gases will be approximately equal to twice the oxygen consumption. The rate of oxygen supply is 2.5-5 m3/(t*min); therefore, the yield rate of converter gases will be 5-10 m3/(t*min) in the middle of the purge. At the beginning and end of the purge, when less carbon is oxidized than in its middle, the amount of exhaust gases decreases.
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