Open AccessThermodynamic analysis of chromium reduction from oxide Cr<sub>2</sub>O<sub>3</sub>
Author(s) -
Ю. С. Кузнецов,
О. И. Качурина
Publication year - 2021
Publication title -
izvestiâ vysših učebnyh zavedenij. černaâ metallurgiâ
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.3
H-Index - 7
eISSN - 2410-2091
pISSN - 0368-0797
DOI - 10.17073/0368-0797-2020-11-12-935-945
Subject(s) - chromium , dissociation (chemistry) , oxide , chemistry , oxidizing agent , analytical chemistry (journal) , hydrogen , carbon monoxide , inorganic chemistry , environmental chemistry , catalysis , biochemistry , organic chemistry
Thermodynamic analysis of chromium reduction from its oxide in gas phase Н 2 – Н 2 О – СО – СО 2 in contact with carbon was performed. Oxidation potential (p O2 ) was determined by two nomograms in the coordinates and taking into account condition normalizations xH2O + xH2 + xCO2+ xCO = 1. In calculations, possible parameters of reduction of chromium from Cr 2 O 3 oxide were determined by ratio of dissociation elasticity of the oxide and oxidation potential of the gas phase. In the СО – СО 2 – С system, chromium is reduced at temperature of 1505 K if x CO > 0.9995. At this temperature, Cr 2 O 3 compound is reduced in water gas of the following composition x H2 = 0.0186, x H2O = 0.28·10–4, x CO = 0.9809, x CO2 = 4.86·10–4, for which the oxidation potential is equal to dissociation elasticity of oxide With an increase in hydrogen concentration from 0.0186 to 0.99, oxidation potential of water gas in contact with carbon decreases by four orders of magnitude to This should lead to a significant increase in reduction rate. In such a gaseous atmosphere, it is possible to reduce chromium at temperature of 1230 K. It is technologically simple to obtain reducing water gas and at the lowest cost, for example, by heating water vapor in contact with carbon. It is shown that at temperature of 1500 K water gas is obtained with traces of Н 2 О and СО 2 compounds with parameters x H2 = 0.4999, x CO = 0.4996, Oxidizing potential of such a gas is less than that of chromium oxide, and this difference significantly increases with increasing temperature.