Direct Carbothermic Reduction of Weathered Ilmenite for Efficient Removal of Iron by Leaching

Journal Article · Sat Jun 15 04:00:00 EDT 2019 · Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science

DOI:https://doi.org/10.1007/S11663-019-01544-W· OSTI ID:22933707

Randhawa, Navneet Singh; Prasad, Sanjay ^[1]

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1. CSIR-National Metallurgical Laboratory, Metal Extraction and Recycling Division (India)

The commercial processes to extract iron from ilmenite (FeTiO{sub 3}) essentially include energy-intensive methods, such as high-temperature reduction smelting or preoxidation, coupled with reduction by carbon. However, due to altered mineralogy of ilmenite caused by weathering at sea coast, the reduction of iron remains incomplete in either of these processes, demanding a high concentration of acid when used for extraction of high-purity TiO{sub 2} for high-end applications. We developed a process for the flux-catalyzed reduction of a partially weathered ilmenite ore of Indian origin. Initially, the effect of flux material and temperature was evaluated using thermogravimetric/diffraction thermal analysis (TG/DTA). The reduction behavior of the fluxed self-reducing pellets of ilmenite was then studied in a raising hearth furnace. The TG/DTA results indicated improved performance of sodium carbonate over lime within a temperature range of 1173 K to 1373 K. Under different reduction conditions in raising hearth furnace experiments, the leaching of reduced ilmenite in diluted hydrochloric acid (6.6 pct concentration) produced different grades of synthetic rutile. The best reduction conditions under optimized parameters enhanced the TiO{sub 2} from initial 51 to 93 wt pct in the synthetic rutile. The X-ray diffraction and electron probe microanalysis investigation of the unreduced and reduced ilmenite revealed the conversion of the Fe{sub x}O{sub y}-SiO{sub 2}-Al{sub 2}O{sub 3} system to Na{sub 2}O-SiO{sub 2}-Al{sub 2}O{sub 3} by sodium carbonate. The thermochemical analysis further explained the influence of sodium carbonate on the liquidus of Na{sub 2}O-SiO{sub 2}-Al{sub 2}O{sub 3} slag. The improved process enables the complete reduction of the iron from weathered ilmenite to produce a high-grade rutile.

• OSTI ID: 22933707
• Journal Information: Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science, Journal Name: Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science Journal Issue: 3 Vol. 50; ISSN 1073-5615; ISSN MTBSEO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CARBON
DIFFERENTIAL THERMAL ANALYSIS
ELECTRON MICROPROBE ANALYSIS
FURNACES
HYDROCHLORIC ACID
ILMENITE
IMPURITIES
IRON
LEACHING
MINERALOGY
REDUCTION
RUTILE
SILICON OXIDES
SLAGS
SMELTING
SODIUM CARBONATES
SODIUM OXIDES
TEMPERATURE RANGE 0400-1000 K
THERMAL GRAVIMETRIC ANALYSIS
TITANIUM OXIDES
X-RAY DIFFRACTION