Türkiye 27. Uluslararası Madencilik Kongresi ve Sergisi (IMCET 2022), Antalya, Turkey, 22 - 25 March 2022, pp.670-681
Chromic oxide is an important basic chemical and finds many applications including
metallurgical materials, green pigments, construction materials, refractory materials and catalysts.
Presently, the industrial production of chromic oxide generally employs two processes : one is the
reduction of sodium dichromate with ammonia sulfate; the other is the thermal decomposition of
chromic anhydride. Both of the processes employ hexavalent chromium as the raw materials. However,
the industrial production of hexavalent chromium compounds, including sodium dichromate and
chromic anhydride, leads to serious environmental problems and low resource utilization.
Cr2O3 is synthesized from chromite ore which is extracted in the Pınarbaşı region in Kayseri via a new
and ecological method. Chromite ore is mixed with the determined amount NaOH and roasted 1000 ⁰C
in the air atmosphere. After that step, we carried out a water leach process for the extraction of
chromium ions. After the water leach step, the solid waste which contains mainly iron, magnesium,
silicon and a part of aluminum could be separated from the solution via filtration. Residual aluminum
cations in the solution were precipitated as an Al(OH)3 in the certain pH. All Cr6+ ions in the solution
were reduced by a certain amount of oxalic acid in the specific pH. The Cr2O3 compound could be successfully synthesized in the final step. The effects of parameters on the preparation yields of
Cr2O3were systematically investigated in this study. Those research datas can be used in the industrial
production of Cr2O3.