Failure cases related to material issues in wet-process phosphoric acid plant

Chandra, K.; Mahanti, Amrita; Kain, Vivekanand; Kumar, Bhupender; Kumar, Niraj; Gautam, Vicky

doi:10.1016/j.engfailanal.2017.05.039

Cited by 13 publications

(2 citation statements)

References 12 publications

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“…The impurities particularly chloride and fluoride are severely corrosive to metals and alloys. This has resulted in several corrosion failures of metallic components handling WPA [9][10][11][12][13]. Severe corrosive conditions exist in the reaction tanks (erosion-corrosion of agitators), evaporators and during transport and storage of acid.…”

Section: Introductionmentioning

confidence: 99%

Comparative corrosion behaviour of stainless steels and their welds in wet-process phosphoric acid

Chandra

Singh

Mahanti

et al. 2021

Corrosion Engineering, Science and Technology

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The present study compares corrosion behaviour of three austenitic stainless steels 316L, 317L and 904L (base materials and welds) in wet-process phosphoric acid (WPA) and reagent grade phosphoric acid with impurities, e.g., Cl-, F-and SO 4 2-. The corrosion study was done by performing electrochemical polarisations at 50°C followed by Tafel extrapolation. Welds always had higher corrosion rates than their respective base materials. The corrosion rates of stainless steels in plant WPA were much less compared to that in reagent grade phosphoric acid with almost similar levels of Cl − , F − and SO 2− 4 . This is due to the presence of a variety of dissolved metallic ions in WPA that reduces its corrosiveness. Among the three metallic cations (Fe 3+ , Mg 2+ and Al 3+ ) examined in this study, the inhibiting action increased in the order Fe 3+ < Mg 2+ < Al 3+ . SS 904L was the most corrosion-resistant alloy in WPA followed by SS 317L and 316L.

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Section: Introductionmentioning

confidence: 99%

Comparative corrosion behaviour of stainless steels and their welds in wet-process phosphoric acid

Chandra

Singh

Mahanti

et al. 2021

Corrosion Engineering, Science and Technology

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“…Currently, there are two primary methods of manufacturing phosphoric acid: the thermal process, the product of which is called thermal process phosphoric acid (TPA), and the wet process, the product of which is called wet-process phosphoric acid (WPA) . Because of its advantages over the thermal process of lower cost, lower energy consumption, and reduced pollutant generation, the wet process is the preferred method, and more than 90% of Chinese factories produce phosphoric acid with this method. − However, the main disadvantage of WPA is that during its manufacturing process, there are many impurities present, among which fluorine is one of the major impurities. − Five main methods have been used to remove fluorine from WPA. They are precipitation, steam stripping, cooling and crystallization, vacuum concentration, and solvent extraction. − Solvent extraction is among the most popular method because of its low cost, high productivity, and high recyclability. − …”

Section: Introductionmentioning

confidence: 99%

Removal of Fluorine from Wet-Process Phosphoric Acid Using a Solvent Extraction Technique with Tributyl Phosphate and Silicon Oil

Zuo

Chen

et al. 2019

ACS Omega

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The deep removal of fluorine from wet-process phosphoric acid is currently a very serious issue. In this paper, an efficient liquid–liquid separation method based on a bubble membrane was developed to solve this problem. Tributyl phosphate (TBP) and silicon oil (SIO) were used as the organic phase. The effects of the component proportion in the organic phase (TBP/SIO v/v), organic to aqueous phase ratio (O/A), pH, temperature, and reaction time on the extraction ratio were investigated. The extraction ratio of fluorine was 98.4% when using only one stage with the following conditions: 90 °C, pH −0.46, volume ratio (TBP/SIO v/v) of 7:3, phase ratio (O/A) of 1:5, stirring speed of 200 rpm, and reaction time of 50 min. Fourier-transform infrared spectroscopy and inverted fluorescence microscopy were used to investigate the reaction mechanism and reaction kinetics. In addition, the scrubbing and stripping process was investigated. When a 2 mol/L sodium hydroxide solution ([NaOH]) was used as the stripping agent with a phase ratio (O/A) of 1:10, a stirring speed of 200 rpm, and a reaction time of 30 min, a maximum stripping ratio of 90.1% was obtained.

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Comparison of the Phase Stability and Corrosion Resistance of the Ni-Based Alloys C-4 and C-276

Tawancy

Alhems

2019

J. of Materi Eng and Perform

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Failure cases related to material issues in wet-process phosphoric acid plant

Cited by 13 publications

References 12 publications

Comparative corrosion behaviour of stainless steels and their welds in wet-process phosphoric acid

Comparative corrosion behaviour of stainless steels and their welds in wet-process phosphoric acid

Removal of Fluorine from Wet-Process Phosphoric Acid Using a Solvent Extraction Technique with Tributyl Phosphate and Silicon Oil

Comparison of the Phase Stability and Corrosion Resistance of the Ni-Based Alloys C-4 and C-276

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