Titanium white sulfuric acid concentration by direct contact membrane distillation

Feng, Xuan; Jiang, Lan Ying; Yang, Song

doi:10.1016/j.cej.2015.09.064

Cited by 56 publications

(6 citation statements)

References 26 publications

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“…It is estimated that 40% of the sulfuric acid used in the SP is eventually released into the environment . As for the acid recovery from the aforementioned effluent, so far, several methods including solvent extraction, , evaporation, and membrane separation , have been investigated, but none was proved economically viable for the titanium pigment industry.…”

Section: Introductionmentioning

confidence: 99%

Development of a Safe and Environmentally Friendly Sulfate Process for the Production of Titanium Oxide

Sadeghi

Esfahany

2022

Ind. Eng. Chem. Res.

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The current research was aimed at developing a safe and more environmentally friendly sulfate process for the production of titanium oxide. In this process, to leach titanium from ilmenite by relatively dilute sulfuric acid (50 wt %), a two-step leaching scheme using a series of stirred tank reactor (STR) and vertical stirred media reactors (SMRs) was devised for carrying out the chemical reaction and particle activation, respectively. The proposed modified sulfate process (MSP) efficiency was 76.5%. The amount of sulfuric acid discarded (100 wt %) from the hydrolysis step per ton of TiO2 was about 100 kg, while this is about 1000 kg in the conventional sulfate process. About 600 kg of quick lime per ton of TiO2 is also saved in the waste acid neutralization section, which ultimately reduces the production of scrap gypsum by about 1700 kg/ton TiO2. The cost balance indicated that processing by the MSP brings about 185 US $/ton TiO2 profit.

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Section: Introductionmentioning

confidence: 99%

Development of a Safe and Environmentally Friendly Sulfate Process for the Production of Titanium Oxide

Sadeghi

Esfahany

2022

Ind. Eng. Chem. Res.

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“…The comprehensive method is an integral solution based on the comprehensive treatment and resource utilization of TWWA (Hu et al, 2020). For example, the extraction method was used for recovery of scandium, vanadium and other rare metals, and the crystallization method was used for recovery of iron, aluminum and titanium Song et al, 2021;Feng et al, 2016). However, the strong acidity of TWWA limited the comprehensive utilization of solvent extraction and crystallization, in which a large amount of alkali was needed to adjust the pH value of the solution to meet the operation requirements of extraction and crystallization.…”

Section: Introductionmentioning

confidence: 99%

Dissolution behavior of representative elements from red mud (RM) by leaching with titanium white waste acid (TWWA)

Zhu

2022

Preprint

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The leaching parameters on the leaching efficiency of representative elements (Na, Sc and Al) were investigated. XRD and SEM-EDS were used to analyze the phase change of RM and leaching residue, and the leaching kinetics characteristics difference of Na, Sc and Al from RM was analyzed by the unreacted shrinking core model (USCM). The results show that the dealkalization efficiency was close to 100%, and the leaching efficiency of Sc and Al was 82% and 75%, respectively. The cancrinite was dissolved from RM by TWWA, and then the elements such as Na, Al and Ca also reacted with H2SO4 of TWWA. Sodium existed in the leaching liquor in the form of ions, and calcium reacted with sulfuric acid to form anhydrite and existed in leaching residue. The particles of RM became smaller and dispersed with each other after leaching. The apparent activation energy of Na, Sc and Al leaching was 4.947 kJ/mol, 6.361 kJ/mol and 31.666 kJ/mol, respectively. The kinetic equation of Na leaching was 1-(1-a)2/3=0.084·exp[-595.05/T]·t controlled by external diffusion. The kinetic equation of Sc leaching was 1-2a/3-(1-a)2/3=0.021·exp[-765.16/T]·t controlled by internal diffusion. The kinetic equation of Al leaching was ln(1-a)/3+ (1-a)-2/3-1=67.12·exp[-3808.8/T]·t controlled by joint action, respectively.

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“…In the production of titanium dioxide by a sulphuric acid process, 5-8 tons of waste sulfuric acid containing 19%~23% of sulfuric acid will be produced per ton of titanium dioxide. In addition, waste acid also contains a large number of valuable metals such as iron, titanium, and trace scandium [2][3][4]. At present, neutralization and concentration methods have been widely used to treat waste acid in China and other countries.…”

Section: Introductionmentioning

confidence: 99%

Solvent Extraction of Sc(III) by D2EHPA/TBP from the Leaching Solution of Vanadium Slag

Cao

Zhang

et al. 2020

Metals

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The solvent extraction of scandium by the mixture of di-(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP) has been investigated in the acidic leaching solution of vanadium slag. Thermodynamic analysis of the species distribution diagrams on the Sc-S-H2O system showed that scandium mainly exists as Sc3+ and Sc(SO4)+, and sulfur mainly exists as HSO4− in the actual leaching solution of vanadium slag (pH = −0.75). The extraction process was studied to optimize various parameters such as the extractant concentration, dosage of TBP, phase ratio, and stirring speed. The results indicated that 83.64% of scandium and less than 2% of co-extracted elements were extracted under optimal conditions. Then, over 95% of the co-extracted elements and less than 1.1% of scandium were scrubbed from the loaded organic phase by 4.0 mol/L of HCl. Finally, 87.20% of scandium was stripped with 2 mol/L of NaOH and 1 mol/L of NaCl at a stripping O/A of 1:1.

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Titanium white sulfuric acid concentration by direct contact membrane distillation

Cited by 56 publications

References 26 publications

Development of a Safe and Environmentally Friendly Sulfate Process for the Production of Titanium Oxide

Development of a Safe and Environmentally Friendly Sulfate Process for the Production of Titanium Oxide

Dissolution behavior of representative elements from red mud (RM) by leaching with titanium white waste acid (TWWA)

Solvent Extraction of Sc(III) by D2EHPA/TBP from the Leaching Solution of Vanadium Slag

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