Dissolution studies of mechanically activated Manavalakurichi ilmenite with HCl and H2SO4

Sasikumar, C.; Rao, D. Sreenivasa; Srikanth, S.; Mukhopadhyay, N. K.; Mehrotra, Shanta

doi:10.1016/j.hydromet.2007.03.013

Cited by 64 publications

(35 citation statements)

References 21 publications

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“…Dissolution of ilmenite can be summarised by reaction (1) which implies that a high sulfuric concentration should aid dissolution, which is indeed the case. (Zhang and Nicol, 2009;Lasheen, 2009;Sasikumar et al, 2007;Liang et al, 2005;Welham and Llewellyn, 1998;Grey et al, 1996;Han et al, 1987;Barton and McConnel, 1979;Barksdale, 1966) FeTiO 3 (s) + 2H 2 SO 4 (aq) = TiOSO 4 (s) + FeSO 4 (s) + 2H 2 O (l)…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Kinetics of the dissolution of ilmenite in sulfuric acid solutions under reducing conditions

Zhang

Nicol

2010

Hydrometallurgy

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Please cite this article as: Zhang, Suchun, Nicol, Michael J., Kinetics of the dissolution of ilmenite in sulfuric acid solutions under reducing conditions, Hydrometallurgy (2010), doi: 10.1016/j.hydromet.2010.03.019 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT ABSTRACTThe kinetics of the dissolution of titanium and iron from an ilmenite sample has been studied in moderately strong sulfuric acid solutions in the absence and presence of reducing agents such as titanium(III) ions and sulfur dioxide. The effects of particle size, temperature, solid/liquid ratio, sulfuric acid concentration and titanium(III) concentration on the kinetics of dissolution have been investigated. The results have shown that both particle size and acid concentration have relatively minor effects on the rate of dissolution of titanium while temperature has a significant effect under the studied conditions.The batch leach kinetics of ilmenite in acid solutions appears to fit a shrinking particle model, while in the presence of a decreasing titanium(III) concentration, the rate of dissolution of titanium can be fitted to a shrinking core model. Mathematical expressions for the batch leaching of the ilmenite have been established. The results suggest that the rate of dissolution of ilmenite in acid solutions is controlled by a slow chemical reaction on the surface of the mineral, while in the presence of a reducing agent such as titanous ions, the dissolution rate of ilmenite is significantly enhanced. The use of SO 2 as a reductant increases the dissolution of titanium only in the presence of ferrous ions. The role of Ti(III) ions and SO 2 during leaching is assumed to involve reduction of the iron(III) component in the mineral by a redox reaction on the surface.

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Section: Accepted M Manuscriptmentioning

confidence: 99%

Kinetics of the dissolution of ilmenite in sulfuric acid solutions under reducing conditions

Zhang

Nicol

2010

Hydrometallurgy

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“…The dissolution of ilmenite minerals in sulfuric acid solutions is significantly accelerated under reductive conditions. However, despite the industrial importance of the sulfate route for ilmenite dissolution for producing pigment TiO 2 there has been surprisingly little published on the kinetics and mechanisms of the dissolution of ilmenite in strong sulfuric acid (Barton and McConnel, 1979;Han et al, 1987;Liang et al, 2005;Sasikumar et al, 2007).…”

Section: (B)mentioning

confidence: 99%

An electrochemical study of the reduction and dissolution of ilmenite in sulfuric acid solutions

Zhang

Nicol

2009

Hydrometallurgy

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Electrochemical techniques have been used to investigate the reduction and dissolution of two different ilmenite samples in 450 g L -1 sulfuric acid solutions at elevated temperatures. The results have shown that the dissolution rate of ilmenite (FeTiO 3 ) is low at potentials above about 0.3 V at which potentials the dissolution of ilmenite and the reduction of hematite (if present in the ilmenite sample) are the main reactions. At more negative potentials the dissolution of ilmenite increases simultaneously with reduction of ilmenite to trivalent titanium. These observations are consistent with those predicted from thermodynamic data. Hematite has a higher dissolution rate under reductive conditions than ilmenite. Studies of the effect of temperature on the dissolution of ilmenite at low potentials such as 0 V have shown that in the temperature range of 65-95 o C, the activation energy is about 50 kJ mol -1 and this together with the high ratio of the charge passed to metals dissolved suggests that the rate of the non-reductive dissolution reaction is not significant under these conditions.

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“…When subjected to enough mechanical energy, the chemical bonds in solids can be effectively broken up, along with the collapse of their crystal structure, phase transformation, and the changes in surface characteristics [1,22]. In addition, a part of mechanical energy is converted into thermal energy which can also affect the physicochemical properties of the solids, especially the polymers.…”

Section: Introductionmentioning

confidence: 99%

Material properties of partially pregelatinized cassava starch prepared by mechanical activation

et al. 2013

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This study has focused on the preparation of partially pregelatinized cassava starch (PPCS) by mechanical activation (MA) using a customized stirring ball mill. The changes in degree of gelatinization, crystal structure, particle size, surface morphology, powder characteristics, and pasting properties of cassava starch mechanically activated for different time were investigated by various characterizations. The results showed that MA could significantly destroy the crystal structure of starch granules, contributing to the increase of cold-water solubility, flowability, and floodability, the variations of particle size and surface morphology, and the decrease in pasting temperature, viscosity of cooked PPCS paste, breakdown, and setback. It was also found that the PPCS with different degree of gelatinization could be prepared by controlling the milling time. With the unique properties induced by MA, the potential use of PPCS as excipient in pharmaceutical formulations is discussed.

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Dissolution studies of mechanically activated Manavalakurichi ilmenite with HCl and H2SO4

Cited by 64 publications

References 21 publications

Kinetics of the dissolution of ilmenite in sulfuric acid solutions under reducing conditions

Kinetics of the dissolution of ilmenite in sulfuric acid solutions under reducing conditions

An electrochemical study of the reduction and dissolution of ilmenite in sulfuric acid solutions

Material properties of partially pregelatinized cassava starch prepared by mechanical activation

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