Dataset Information

Effects of Impurities on CaSO₄ Crystallization in the Ca(H₂PO₄)₂-H₂SO₄-H₃PO₄-H₂O System.

ABSTRACT: Wet-process phosphoric acid is a fundamental process in the fertilizer industry. The influence of impurities on crystallization kinetics of CaSO₄ was investigated in the Ca(H₂PO₄)₂-H₂SO₄-H₃PO₄-H₂O system using a mixed suspension mixed product removal crystallizer. Effects of Si, Al, Fe, Mg, K, and Na on crystal morphology and structure were examined in the highly acidic system through scanning electron microscopy and high-resolution transmission electron microscopy. Results show that the increase of Mg, K, and Na content facilitates crystal growth. Si, Al, and Fe are beneficial to CaSO₄ crystal growth at a certain concentration range. Impurities also affect the crystal morphology, and the addition of Si, Fe, and Na promotes the formation of needle-like crystals compared with other impurities. X-ray diffraction results show that the preferred crystal growth direction is (020), and the interplanar spacing of the crystals is affected by the element radius of the impurities.

SUBMITTER: Mu X

PROVIDER: S-EPMC6682056 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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Publications

Effects of Impurities on CaSO4 Crystallization in the Ca(H2PO4)2-H2SO4-H3PO4-H2O System.

Mu Xinru X Zhu Ganyu G Li Xu X Li Shaopeng S Gong Xiaokang X Li Huiquan H Sun Guoxin G

ACS omega 20190725 7

Wet-process phosphoric acid is a fundamental process in the fertilizer industry. The influence of impurities on crystallization kinetics of CaSO4 was investigated in the Ca(H2PO4)2-H2SO4-H3PO4-H2O system using a mixed suspension mixed product removal crystallizer. Effects of Si, Al, Fe, Mg, K, and Na on crystal morphology and structure were examined in the highly acidic system through scanning elec ...[more]

PMID: 31460392

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Project description:Nitroxide free radicals can serve as redox-sensitive MRI contrast agents useful to image the redox status of tissue of interest. In this study, the effect of oxygen content in the inspired gas on the kinetics of metabolism of three nitroxides has been evaluated in the muscle and tumor in mice. SCC tumors (approximate size of 1.0 cm3) on the right hind leg of female C3H/Hen MTV- mice were prepared. Three nitroxides, 3-carboxy-2,2,5,5-tetramethylpyrrolidine-N-oxyl (CxP), 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl (CmP), and 4-hydroxy-tetramethylpiperidine-N-oxyl (TEMPOL), having different lipophilicities were compared using MR redox imaging. T1-mapping of the tissues was obtained using a multi-slice multi-echo (MSME) sequence with several TRs. The three nitroxides showed differences in accumulation and metabolism/clearance in muscle and tumor. The cell impermeable nitroxide CxP displayed kinetic patterns of slow enhancement followed by a slow decline typical of clearance rather than metabolism. The cell permeable CmP on the other hand showed a relatively faster uptake and metabolism with a modestly higher rate of metabolism in the tumor than muscle. The TEMPOL on the other hand displayed a rapid uptake and reduction with a trend of significantly rapid decay rate in tumor tissue, while slightly higher maximum signal intensity and slower decay rate was observed in normal muscle. The reduction rate of TEMPOL in the tumor was significantly enhanced when the breathing gas had 100%-oxygen while it was not significantly different in the muscle. EPR oximetry studies monitoring the oxygen dependent linewidth of TEMPOL showed that the pO2 in the healthy tissue during carbogen breathing significantly increased normal tissue pO2 compared to air breathing whereas breathing 100%-oxygen made normal tissue slight hypoxic. Since TEMPOL is a radioprotector, our studies show that a combination of 100%-oxygen breathing and TEMPOL has a potential to enhance radioprotective effects to normal tissue.

Dataset Information

Effects of Impurities on CaSO₄ Crystallization in the Ca(H₂PO₄)₂-H₂SO₄-H₃PO₄-H₂O System.

Publications

Effects of Impurities on CaSO<sub>4</sub> Crystallization in the Ca(H<sub>2</sub>PO<sub>4</sub>)<sub>2</sub>-H<sub>2</sub>SO<sub>4</sub>-H<sub>3</sub>PO<sub>4</sub>-H<sub>2</sub>O System.

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