MODELING THE FERROSILICOMANGANESE SMELTING PROCESS USING MANGANESE-RICH SLAG

Abstract

This article presents the results of complete thermodynamic modeling (TDM) of the smelting process of standard ferrosilicomanga-nese (FeSiMn) from the slag of refined ferromanganese and manganese ores of Kazakhstan. Complete thermodynamic modeling of the smelting process of standard ferrosilicomanganese was performed in the software package "HSC Chemistry 6". The principle of operation of this software package is based on the principle of maximum entropy and takes into account all known properties of the reacting components that make up the thermodynamic system. The simulation of chemical and phase transformations in the systemwas studied in the temperature range 500-2200 °C for six real charge compositions with a carbon content of 8-10-12-14-16-18 kg and a pressure of 0.1 MPa. The mechanism of joint carbothermic reduction of manganese, silicon, aluminum, calcium and iron was studied using the Mn-Si-Al-Ca-Mg-O-C system. The calculations carried out make it possible to fullyconsider all the physicochemicalpro-cesses occurring during the smelting of standard ferrosilicomanganese by the carbothermic method. During the simulation, it was found that the production of the metal phase of standard ferrosilicomanganese corresponded to GOST 4756-91 at a temperature of 1600-1700 °C with a carbon content of 12-14 kg per 100 kg of charge. With a further increase in temperature, manganese and silicon begin to enter the gas phase. The chemical composition of the alloy at 1700 °C with a content of 12 kg, %: Mn –73.05; Si –16.24; Fe –9.67 and C –1.03, and with a content of 14 kg is, %: Mn –73.15; Si –17.12; Fe –8.24 and C –1.48. The thermodynamic modeling of the phase transitions of the manganese charge–reducingagent subsystem made it possible to analyze the possibility of obtaining ferrosilicomanganese from hard-to-recover oxidized manganese ores of the Zhayrem deposit and manganese slag by electric melting. Alsopresents the results of experimental melting of silicomanganese, carried out in a Tamman laboratory furnace at a tem-perature of 1650 °C with an exposure of 20 minutes in a graphite crucible (manganese ore -35%, manganese slag -35%, Shubarkol coal -30%)