The Experts below are selected from a list of 169950 Experts worldwide ranked by ideXlab platform
Keqiang Qiu - One of the best experts on this subject based on the ideXlab platform.
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vacuum pyrolysis and hydrometallurgical process for the recovery of valuable metals from spent lithium ion batteries
Journal of Hazardous Materials, 2011Co-Authors: Liang Sun, Keqiang QiuAbstract:Abstract Spent lithium-ion batteries contain lots of strategic resources such as cobalt and lithium together with other hazardous materials, which are considered as an attractive secondary resource and environmental contaminant. In this work, a novel process involving vacuum pyrolysis and hydrometallurgical technique was developed for the combined recovery of cobalt and lithium from spent lithium-ion batteries. The results of vacuum pyrolysis of cathode material showed that the cathode powder composing of LiCoO 2 and CoO peeled completely from aluminum foils under the following experimental conditions: temperature of 600 °C, vacuum evaporation time of 30 min, and residual gas pressure of 1.0 kPa. Over 99% of cobalt and lithium could be recovered from peeled cobalt lithium oxides with 2 M sulfuric acid leaching solution at 80 °C and solid/liquid ratio of 50 g L −1 for 60 min. This technology offers an efficient way to recycle valuable materials from spent lithium-ion batteries, and it is feasible to scale up and help to reduce the environmental pollution of spent lithium-ion batteries.
Liang Sun - One of the best experts on this subject based on the ideXlab platform.
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vacuum pyrolysis and hydrometallurgical process for the recovery of valuable metals from spent lithium ion batteries
Journal of Hazardous Materials, 2011Co-Authors: Liang Sun, Keqiang QiuAbstract:Abstract Spent lithium-ion batteries contain lots of strategic resources such as cobalt and lithium together with other hazardous materials, which are considered as an attractive secondary resource and environmental contaminant. In this work, a novel process involving vacuum pyrolysis and hydrometallurgical technique was developed for the combined recovery of cobalt and lithium from spent lithium-ion batteries. The results of vacuum pyrolysis of cathode material showed that the cathode powder composing of LiCoO 2 and CoO peeled completely from aluminum foils under the following experimental conditions: temperature of 600 °C, vacuum evaporation time of 30 min, and residual gas pressure of 1.0 kPa. Over 99% of cobalt and lithium could be recovered from peeled cobalt lithium oxides with 2 M sulfuric acid leaching solution at 80 °C and solid/liquid ratio of 50 g L −1 for 60 min. This technology offers an efficient way to recycle valuable materials from spent lithium-ion batteries, and it is feasible to scale up and help to reduce the environmental pollution of spent lithium-ion batteries.
Shun Myung Shin - One of the best experts on this subject based on the ideXlab platform.
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recovery of cobalt sulfate from spent lithium ion batteries by reductive leaching and solvent extraction with cyanex 272
Hydrometallurgy, 2010Co-Authors: Jingu Kang, Jeongsoo Sohn, G Senanayake, Shun Myung ShinAbstract:Cobalt sulfate was recovered from crushed and screened prismatic type spent lithium ion batteries (LIBs) containing 5-20% Co, 5-7% Li, 5-10% Ni, 15% organic chemicals, and 7% plastics together with Cu, Al, Fe, and Mn. Cobalt was reductively leached from the - 16 mesh fraction in 1 h by stirring with 2 M H2SO4 and 6 vol.% H2O2, at 60 °C and 300 rpm using a solid/liquid ratio of 100 g/L to give a cobalt concentration of 28 g/L, corresponding to a leaching efficiency of > 99%. Metal ion impurities such as copper, iron, and aluminium were precipitated as hydroxides from solution by adjusting pH to 6.5. Cobalt was then selectively extracted from the purified aqueous phase by equilibrating with 50% saponified 0.4 M Cyanex 272 at an equilibrium pH ∼ 6. The McCabe-Thiele plot predicted 99.9% cobalt extraction in a 2 stage counter-current operation with A/O ratio of 1/2. Separation factors for the extraction of Co/Li and Co/Ni at pH 6 were close to 750. The stripping of the loaded organic phase with 2 M H2SO4 produced a solution of 96 g/L Co from which pure pigment grade cobalt sulfate could be recovered by evaporation/recrystallisation. Overall, 92% cobalt could be recovered from the spent lithium ion batteries.
Shigeki Shibahara - One of the best experts on this subject based on the ideXlab platform.
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Coexpression of erythropoietin and heme oxygenase genes in Hep3B cells
Hepatology, 1993Co-Authors: J. D. Lutton, Nader G. Abraham, Margaret O. Griffin, Miki Nishimura, Richard D. Levere, Attallah Kappas, Shigeki ShibaharaAbstract:Exposure of Hep3B cells to metalloporphyrins (tinprotoporphyrin and heme) or cobalt chloride resulted in the production of a significant number of heme oxygenase transcripts, erythropoietin transcripts or both, as indicated by in situ hybridization. Exposure to heme 10 μmol/L resulted in a 30-fold to 40-fold increase in cells expressing erythropoietin messenger RNA (erythropoietin-positive cells) by 6 hr; this increased level remained elevated for 24 hr. Tin-protoporphyrin (10 μmol/L) produced an eightfold to 10-fold increase in erythropoietin RNA within 40 min. This value then returned to control levels by 60 min. Exposure to cobalt chloride (100 μmol/L) resulted in a 20-fold to 30-fold increase in erythropoietin expression for 5 to 20 min, returning to control by 40 min. Additionally, nuclear runoff assays demonstrated that the increase in heme oxygenase or erythropoietin messenger RNA accumulation by cobalt chloride appeared to be a result of stimulated transcription of the heme oxygenase and erythropoietin genes. However, the pattern for heme oxygenase messenger RNA induction was different from that for erythropoietin expression. Heme produced an immediate expression of heme oxygenase RNA (50-fold within 5 min) and a second sustained response during the next 24 hr. Tin-protoporphyrin also produced an immediate response (40-fold within 5 min) and remained elevated (20-fold) for 6 hr. Cobalt chloride produced a 22-fold increase within 20 min and returned to the control value by 1 hr. Thus both erythropoietin and heme oxygenase genes appear to be expressed after treatment with tin-protoporphyrin, heme or cobalt chloride; however, the time and patterns of expression are different. The most significant feature of coexpression appears to be that induced by heme, where heme oxygenase is immediately expressed (5 min) with a second sustained expression during the next 10 to 24 hr, whereas erythropoietin sustained expression for 3 to 24 hr. (HEPATOLOGY 1993;17:861–868.)
Ervin B. Podgorsak - One of the best experts on this subject based on the ideXlab platform.
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Viability of an isocentric Cobalt-60 teletherapy unit for stereotactic radiosurgery
Medical physics, 1998Co-Authors: Brett A. Poffenbarger, Ervin B. PodgorsakAbstract:The potential for radiosurgery with an isocentric teletherapy cobalt unit was evaluated in three areas: (1) the physical properties of radiosurgical beams, (2) the quality of radiosurgical dose distributions obtained with four to ten noncoplanar converging arcs, and (3) the accuracy with which the radiosurgical dose can be delivered. In each of these areas the cobalt unit provides a viable alternative to an isocentric linear accelerator (linac) as a radiation source for radiosurgery. A 10 MV x-ray beam from a linac used for radiosurgery served as a standard for comparison. The difference between the 80%-20% penumbras of stationary radiosurgical fields in the nominal diameter range from 10 to 40 mm of the Cobalt-60 and 10 MV photon beams is remarkably small, with the Cobalt-60 beam penumbras, on average, only about 0.7 mm larger than those of the linac beam. Differences between the Cobalt-60 and 10 MV radiosurgical treatment plans in terms of dose homogeneity within the target volume, conformity of the prescribed isodose volume to the target volume, and dose falloffs outside the target volume are also minimal, and therefore of essentially no clinical significance. Moreover, measured isodose distributions for a radiosurgical procedure on our Theratron T-780 cobalt unit agreed with calculated distributions to within the +/- 1 mm spatial and +/- 5% numerical dose tolerances, which are generally specified for radiosurgery. The viability of isocentric cobalt units for radiosurgery will be of particular interest to centers in developing countries where cobalt units, because of their relatively low costs, provide the only megavoltage source of radiation for radiotherapy, and could easily and inexpensively be modified for radiosurgery. Of course, the quality assurance protocols and mechanical condition of a particular teletherapy cobalt unit must meet stringent requirements before the use of the unit for radiosurgery can be advocated.