Influence of Pre-oxidation on Carbothermic Reduction Process of Ilmenite Concentrate

Processing of titanium-containing ores with extraction of all the major elements is an urgent task of minerals rational use. It is shown that none of the existing processing schemes allows extracting of all the major useful elements at the same time from titanium-containing iron ores, i.e. – iron, titanium and vanadium. This problem can be solved using selective extraction of these elements based on new ideas about electronic reduction mechanism. Propagation of the process of solid-phase selective reduction of iron with the powder of carbon-containing material deep into the layer of grains of ilmenite concentrate from the surface of its contact was experimentally studied. The results of determining the amount of metal phase released as it moves away from the concentrate – reducing agent contact boundary are presented. Based on the results concerning amount of precipitated metal phase, a conclusion was made about diffusion processes in a layer of concentrate grains contacting only between themselves, limiting process of iron reduction. It is shown that near the plane of contact of solid reducing agent with the layer of concentrate grains, the rate of iron reduction is higher than the rate of high iron content phase precipitation from ilmenite. In depth of ilmenite concentrate layer, process of iron reduction is preceded by formation of iron-containing silicate phase from concentrate grains, where iron is reduced earlier than in ilmenite grains. Formation of iron-containing silicate phase contributes ilmenite grains sintering. It was concluded that in the concentrate layer in contact with solid reducing agent layer in absence of contact of each ilmenite grain with solid reducing agent, the point contact of grains and presence of voids between them in the layer do not prevent propagation of reduction process in the layer of grains contacting with each other only.

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Experimental Study on Strengthening Carbothermic Reduction of Vanadium-Titanium-Magnetite by Adding CaF2

Minerals ◽

10.3390/min10030219 ◽

2020 ◽

Vol 10 (3) ◽

pp. 219 ◽

Cited By ~ 1

Author(s):

Xiangdong Xing ◽

Yueli Du ◽

Jianlu Zheng ◽

Yunfei Chen ◽

Shan Ren ◽

...

Keyword(s):

Carbothermic Reduction ◽

Reduction Rate ◽

Reduction Process ◽

Complex Compounds ◽

Carbon Gasification ◽

Promotive Effect ◽

Mass Fractions ◽

Vanadium Titanium ◽

Gasification Reaction ◽

Titanium Magnetite

The effects and reduction mechanisms of carbothermic reduction of vanadium–titanium–magnetite were studied by adding various mass fractions of CaF2 ranging from 0%, 1%, 3%, 5% to 7%. The results showed that the proper CaF2 addition could strengthen the carbothermic reduction of vanadium–titanium–magnetite while the excessive amounts will weaken the promotive effect, hence the appropriate dosage was determined to be 3 mass%. The CaF2 was favorable for the carbon gasification reaction, where it increased the partial pressure of CO inside briquette and caused the lattice distortion of vanadium–titanium–magnetite. The reaction improved the reduction process and accelerated the reduction rate. The appearance of 3CaO·2SiO2·CaF2 and other complex compounds with low melting point facilitated the aggregation and growth of the slag and the iron, which increased the concentration of iron grains and the aggregation level of the slag.

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Removal of Metallic Iron from Reduced Ilmenite by Aeration Leaching

Metals ◽

10.3390/met10081020 ◽

2020 ◽

Vol 10 (8) ◽

pp. 1020

Author(s):

Qiuyue Zhao ◽

Maoyuan Li ◽

Lei Zhou ◽

Mingzhao Zheng ◽

Ting’an Zhang

Keyword(s):

Iron Content ◽

Metallic Iron ◽

Carbothermic Reduction ◽

Room Temperature ◽

Total Iron ◽

Total Iron Content ◽

Tio2 Content ◽

Synthetic Rutile ◽

Ilmenite Concentrate ◽

Hcl Solution

Aeration leaching was used to obtain synthetic rutile from a reduced ilmenite. The reduced ilmenite, obtained from the carbothermic reduction of ilmenite concentrate in a rotary kiln at about 1100 °C, contained 62.88% TiO2 and 28.93% Metallic iron. The particle size was about 200 μm and the size distribution was uniform. The effects of NH4Cl and HCl concentrations, stirring speed, and aeration leaching time on the extent of removal of metallic iron from the reduced ilmenite were studied at room temperature. The results revealed that aeration leaching is feasible at room temperature. When using the NH4Cl system, the metallic iron content was reduced to 1.98% in synthetic rutile, but the TiO2 content only reached 69.16%. Higher NH4Cl concentration did not improve the leaching. Using 2% NH4Cl with 3% HCl, we were able to upgrade the synthetic rutile to 75%, with a metallic iron content as low as 0.14% and a total iron content of about 4%. Synthetic rutile could be upgraded to about 90% using HCl solution alone. HCl and NH4Cl are both effective on the aeration leaching process. However, within the scope of this experiment, hydrochloric acid is more efficient in aeration leaching.

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