Chlorination Of Ilmenite Research Articles

Kinetic Study of Selective Chlorination of Iron in Ilmenite Ore

The selective chlorination of ilmenite with coke and chlorine gas was conducted in the fixed bed reactor and effects of coke content and reaction temperature on reaction rate were investigated. In particular, the chlorination rate of iron in ilmenite was simulated by the unreacted shrinking core model. The reaction rate was simulated by calculating the chlorine gas consumption rate as the unreacted core shrinks. In addition, each of reaction resistances that chemical reaction at the reaction interface, diffusion through the product layer, and boundary film mass transfer resistances were calculated. The simulated reaction rates were in good agreement with the experimental results and the rate controlling step changed as the chlorination reaction progressed. Furthermore, the diffusion resistance through the product layer was dominant at lower reaction temperature, whereas the chemical reaction was dominant as the reaction temperature increased. It is because the diffusion of chlorine gas through the product layer could be hindered at lower reaction temperatures. Key words: Ilmenite, Selective chlorination, Synthetic rutile, Shrinking core model

Ilmenite Chlorination: Usage of Gaseous Carbon Tetrachloride at Relatively Lower Temperatures

Malaysian ilmenite from “amang” or tin mining waste is well known for its physical and chemical complexity, making it difficult to be treated conventionally. With knowledge of ilmenite is rich in titania and iron, extractive efforts were made in order to segregate and recover the components of ilmenite, with major interest being the removal and retrieval of titanium. In this study, the extent of chlorination execution is observed by means of weight loss studies under various parameters, with an aim of successful chlorination at lower temperatures. At 723 K, chlorination trials were done using gaseous hydrogen chloride (gHCl), carbon monoxide-chlorine gas mixtures (gCO-Cl) and gaseous carbon tetrachloride (gCT). It was clearly seen that at such a relatively low temperature, only gCT was able to obtain a good chlorination degree, with up to 90% chlorination of –45+37 μm ilmenite particles were observed after 1 hour of reaction. With similar size fraction and time, hydrogen chloride was only able to give approximately 6% of chlorination while the mixture of carbon monoxide and chlorine was seen incapable of giving anything higher than a 6% reaction. Initial observation suggests that the chlorination of ilmenite by carbon tetrachloride physically resembles the core shrinking model, although proper kinetic studies needs to be done to confirm this. Changes in various parameter values are seen to be quite sensitive to the overall ilmenite chlorination (via gCT) process. This study have shown that gCT presents an interesting route for the chlorination of complex ores such as ilmenite.

Utilisation of Salts from Inland Saline Water Sources

Processing of saline water to produce industrial minerals with large volume applications is considered one way to attack the salinity problem in the Murray-Darling Basin. We propose that saline water in the Basin be treated to produce industrial mineral salts such as sodium chloride, magnesium sulphate, and magnesium chloride. The magnesium-rich bittern fraction of the saline waters may be processed further to value-added products such as magnesium hydroxide, Sorel cement, or spinel refractories. Sorel cement could be consumed in large quantities in the Basin as construction material and may be used to seal new interception scheme lakes, although the stability of the Sorel cement in aqueous environment remains to be investigated.The processing of mineral sands can be linked with treatment of saline water in an integrated and cost-effective manner that aims to remove salt from the Basin. The sodium chloride fraction can be used to produce chemicals such as chlorine, hydrochloric acid and sodium hydroxide that can be used in the processing of zircon. Direct chlorination of ilmenite could consume the equivalent of about 1.4 tonnes of sodium chloride for each tonne of ilmenite treated if no chlorine was recycled. Chlorination of synthetic rutile (about 90% TiO2) could consume the equivalent of about 0.3 tonnes of sodium chloride for each tonne of titania pigment produced. Work in CSIRO Minerals has produced low radioactivity zirconia from a Murray Basin zircon by caustic soda decomposition followed by concentrated hydrochloric acid leaching.In addition, it is proposed that desalination plants be established across the Basin to recover fresh water, heat, and electricity from saline water. These plants will obtain heat and electricity from solar power generation schemes with storage of power in solar ponds and molten salts.Integrated saline water and mineral sands mining industry in the Basin may ultimately lead to new technology for Australia such as titanium metal production. Titanium metal produced from TiO2 pigment may be used in building desalination plants across the Basin to recover fresh water from saline waters.

Entrained-flow chlorination of ilmenite to produce titanium tetrachloride and metallic iron

The reaction of FeCl2 vapor with TiO2 in ilmenite to yield TiCl4 and metallic iron was studied at 1523 to 1723 K in an entrained-flow reactor. Ilmenite/carbon mixtures containing carbons with internal surface areas from 1 to 600 m2/g were milled to various average particle diameters ranging from 6 to 65 μm. Up to 44 pct of the stoichiometric FeCl2 reacted at the highest retention time of 34 seconds when a sixfold excess of FeCl2 vapor was used. Maximum ex-perimental reaction yields were only about two thirds of the theoretical yield calculated for equilibrium conditions. For large particles, a negative effect of temperature on reaction rate indicated that the reaction rate was controlled by ash layer diffusion resistance. For small par-ticles, under the higher turbulence conditions, the early stages of reaction appear to be influ-enced by film mass transfer.

A model for gas-solid reactions with structural changes in the presence of inert solids

A mathematical model is developed to account for the effect of inert material present in the solid in noncatalytic gas-solid reactions accompanied by significant structural changes. This model finds application in the desulfurization of flue gases using dolomite, chlorination of ilmenite, etc. where the naturally occurring ores contain inert materials in the solid matrix. The results show that the asymptotic conversion is increased by the presence of inerts and an optimum inert content exists for which the gas uptake and the utilization of the active solid material are maximum.