The reactivity of iron oxides and hydroxide during low-temperature sulfation

Gontijo, Vitor L.; Teixeira, Leandro Augusto Viana; Ciminelli, Virgínia S. T.

doi:10.1016/j.hydromet.2020.105452

Cited by 7 publications

(3 citation statements)

References 21 publications

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“…The dissolution in water produces a liquor containing various metals, not only the one of interest. This technique aims to transform a difficult-to-leach metal oxide to a more readily leachable metal sulphate [10,14,15,[29][30][31]. The sulphuric digestion of titanium ore followed by leaching with water, produces a liquor rich in soluble titanyl sulphate (TiOSO 4 ), however, it also contains some impurities.…”

Section: Sulphuric Acid Digestionmentioning

confidence: 99%

“…Niobium, in turn, showed a considerable increase in solubilization for the 4 h of digestion, reaching 76% of dissolution, while for the other times of digestion the metallurgical recoveries are close to 61%. The decrease in titanium extraction over time can be associated with the formation of a solid product layer, i.e., a ferric sulphate layer, which limits the progression of the reaction by blocking the diffusion of sulphuric acid towards the reaction front [14]. In addition to leaching using water, another alternative to dissolve the titanium sulphate after the sulphuric acid digestion, is to leach the material with dilute sulphuric acid.…”

Section: Effect Of Time In Sulphuric Digestionmentioning

confidence: 99%

“…Sulphuric acid digestion is the first stage of the sulphate process and consists of the digestion of the raw material (fine grain size 90% < 44 µm) with concentrated sulphuric acid (80-98%), at temperatures between 170 and 220 • C, and reaction times that vary from 2 to 6 h. After the reaction time, the solid is leached with water to promote the solubilization of sulphates and to obtain a liquor containing the metal of interest [10,14,15]. In the case of titanium, the raw material is converted to solid titanyl sulphate (TiOSO 4 ), which is soluble in water and can be leached into a titanyl sulphate rich liquor.…”

Section: Introductionmentioning

confidence: 99%

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Sulphuric Acid Digestion of Anatase Concentrate

da Silva,

Nazareth,

de Freitas

et al. 2024

Mining

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The processing of anatase ores by sulphuric acid digestion is well known for its low titanium dissolution yields, which makes the process economically and technically unfeasible. Anatase is considered much less reactive than other forms of titanium such as ilmenite and rutile. Generally, to enhance its dissolution, thermal processes along with acid and/or alkaline leaching processes are necessary. Studies of direct sulphuric acid digestion are few and the reported yields of titanium dissolution are <48%. This study investigated the main parameters of sulphuric digestion of anatase such as temperature, anatase:acid ratio, and time of reaction. Dissolution of titanium of around 86% were obtained at relatively mild conditions such as, temperature at 220 °C, grain size of 62 µm, an anatase:sulphuric acid ratio of 1:2, and 4 h of reaction. A comprehensive characterization of the resulting material indicated a content of 56.5% of TiO2 and 15% iron oxide—the main impurity. It also contained silica, aluminum, phosphorus, calcium, and rare earth elements (REE) in concentrations that varied from 1.61% to 6.01%.

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