Ultrasound-assisted cyanide extraction of gold from gold concentrate at low temperature
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01.06.2020 |
Yu S.
Yu T.
Song W.
Yu X.
Qiao J.
Wang W.
Dong H.
Wu Z.
Dai L.
Li T.
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Ultrasonics Sonochemistry |
10.1016/j.ultsonch.2020.105039 |
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Ссылка
© 2020 Elsevier B.V. A sonochemical reactor was developed to study the ultrasound-assisted cyanide extraction of gold from gold ore at low temperature. The effects of ultrasound on gold leaching in low temperature and conventional conditions were investigated. At the low temperature of 10 °C, ultrasound-assisted extraction increased extraction rate of gold by 0.6%–0.8% and reduced the gold content of cyanide tailings to 0.28 g/t in the leaching of gold concentrate and cyanide tailings, respectively. At the conventional temperature of 25 °C, ultrasound-assisted extraction obtained a 0.1% higher extraction rate of gold compared with conventional extraction, with the unit consumption of NaCN reduction of 15%. The analysis of kinetic model also demonstrated that sonication indeed improved the reaction of gold leaching greatly. The mineralogy and morphology of ore were further analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and particle size analyzer to explore the strengthening mechanism of gold leaching. The results showed that the ore particles were smashed, the ore particle surface was peeled, the passive film was destroyed and the reaction resistance decreased under ultrasonic processing. Therefore, the extraction rate of gold was improved and the extraction time was shortened significantly in ultrasound-assisted cyanide extraction.
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Ultrasound-assisted cyanide extraction of gold from gold concentrate at low temperature
|
01.06.2020 |
Yu S.
Yu T.
Song W.
Yu X.
Qiao J.
Wang W.
Dong H.
Wu Z.
Dai L.
Li T.
|
Ultrasonics Sonochemistry |
10.1016/j.ultsonch.2020.105039 |
0 |
Ссылка
© 2020 Elsevier B.V. A sonochemical reactor was developed to study the ultrasound-assisted cyanide extraction of gold from gold ore at low temperature. The effects of ultrasound on gold leaching in low temperature and conventional conditions were investigated. At the low temperature of 10 °C, ultrasound-assisted extraction increased extraction rate of gold by 0.6%–0.8% and reduced the gold content of cyanide tailings to 0.28 g/t in the leaching of gold concentrate and cyanide tailings, respectively. At the conventional temperature of 25 °C, ultrasound-assisted extraction obtained a 0.1% higher extraction rate of gold compared with conventional extraction, with the unit consumption of NaCN reduction of 15%. The analysis of kinetic model also demonstrated that sonication indeed improved the reaction of gold leaching greatly. The mineralogy and morphology of ore were further analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and particle size analyzer to explore the strengthening mechanism of gold leaching. The results showed that the ore particles were smashed, the ore particle surface was peeled, the passive film was destroyed and the reaction resistance decreased under ultrasonic processing. Therefore, the extraction rate of gold was improved and the extraction time was shortened significantly in ultrasound-assisted cyanide extraction.
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Ultrasound-assisted cyanide extraction of gold from gold concentrate at low temperature
|
01.06.2020 |
Yu S.
Yu T.
Song W.
Yu X.
Qiao J.
Wang W.
Dong H.
Wu Z.
Dai L.
Li T.
|
Ultrasonics Sonochemistry |
10.1016/j.ultsonch.2020.105039 |
0 |
Ссылка
© 2020 Elsevier B.V. A sonochemical reactor was developed to study the ultrasound-assisted cyanide extraction of gold from gold ore at low temperature. The effects of ultrasound on gold leaching in low temperature and conventional conditions were investigated. At the low temperature of 10 °C, ultrasound-assisted extraction increased extraction rate of gold by 0.6%–0.8% and reduced the gold content of cyanide tailings to 0.28 g/t in the leaching of gold concentrate and cyanide tailings, respectively. At the conventional temperature of 25 °C, ultrasound-assisted extraction obtained a 0.1% higher extraction rate of gold compared with conventional extraction, with the unit consumption of NaCN reduction of 15%. The analysis of kinetic model also demonstrated that sonication indeed improved the reaction of gold leaching greatly. The mineralogy and morphology of ore were further analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and particle size analyzer to explore the strengthening mechanism of gold leaching. The results showed that the ore particles were smashed, the ore particle surface was peeled, the passive film was destroyed and the reaction resistance decreased under ultrasonic processing. Therefore, the extraction rate of gold was improved and the extraction time was shortened significantly in ultrasound-assisted cyanide extraction.
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Sono-physical and sono-chemical effects of ultrasound: Primary applications in extraction and freezing operations and influence on food components
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01.01.2020 |
Fu X.
Belwal T.
Cravotto G.
Luo Z.
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Ultrasonics Sonochemistry |
10.1016/j.ultsonch.2019.104726 |
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© 2019 Elsevier B.V. Ultrasound is an advanced non-thermal food-processing technology that has received increasing amounts of interest as an alternative to, or an adjuvant method for, conventional processing techniques. This review explores the sono-physical and sono-chemical effects of ultrasound on food processing as it reviews two typical food-processing applications that are predominantly driven by sono-physical effects, namely ultrasound-assisted extraction (UAE) and ultrasound-assisted freezing (UAF), and the components modifications to food matrices that can be triggered by sono-chemical effects. Efficiency enhancements and quality improvements in products (and extracts) using ultrasound are discussed in terms of mechanism and principles for a range of food-matrix categories, while efforts to improve existing ultrasound-assist patterns was also seen. Furthermore, the progress of experimental ultrasonic equipments for UAE and UAF as food-processing technologies, the core of the development in food-processing techniques is considered. Moreover, sono-chemical reactions that are usually overlooked, such as degradation, oxidation and other particular chemical modifications that occur in common food components under specific conditions, and the influence on bioactivity, which was also affected by food processing to varying degrees, are also summarised. Further trends as well as some challenges for, and limitations of, ultrasound technology for food processing, with UAE and UAF used as examples herein, are also taken into consideration and possible future recommendations were made.
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An improved extraction protocol for therapeutic dabigatran monitoring using HPLC-MS/MS
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01.11.2019 |
Kozlov A.
Ramenskaya G.
Sychev D.
Vlasov A.
Makarenkova L.
Stepanova E.
Gegechkori V.
Agatonovic-Kustrin S.
Chistyakov V.
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Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences |
10.1016/j.jchromb.2019.121808 |
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© 2019 Elsevier B.V. A new sample extraction protocol was developed for pharmacokinetic studies of dabigatran with high-performance liquid chromatography separation - electrospray ionization time-of-flight mass spectrometry analysis. After protein precipitation with acetonitrile, free dabigatran and its metabolites are separated into water phase by water-dichloromethane liquid-liquid extraction to purify the sample from proteins and endogenous lipophilic compounds. Chromatographic separation was achieved on an Agilent Zorbax SB-CN column (150 × 4.6 mm, 5 µm)) using 0.1% aqueous solution of formic acid and acetonitrile (80:20) as the mobile phase. Agilent Zorbax SB-CN column was selected to improve sample resolution and to avoided early elution of dabigatran previously seen when using a C18 column. The extended calibration curve was constructed from 5 to 1000 ng/L while precision and accuracy were assessed at four levels across the linear dynamic ranges. Within-run precision was <5.6% and the between-run precision was <3.9%. The method accuracy ranged from 89.8% to 104.4%. The developed method was successfully applied to 30 patient samples to evaluate antithrombotic efficacy and anticoagulant activity of dabigatran following knee endoprosthesis surgery.
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A Multicenter Study Evaluating Natural Orifice Specimen Extraction Surgery for Rectal Cancer
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01.11.2019 |
Liu Z.
Efetov S.
Guan X.
Zhou H.
Tulina I.
Wang G.
Tsarkov P.
Wang X.
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Journal of Surgical Research |
10.1016/j.jss.2019.05.034 |
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© 2019 Elsevier Inc. Background: Low anterior resections are increasingly performed laparoscopically for rectal cancer. Recently, natural orifice specimen extraction surgery (NOSES) has been reported as an alternative approach without additional incisions or extensions. In this study, we aimed to evaluate the safety and feasibility of NOSES by comparing the short-term outcomes with those of conventional laparoscopic resection (CLR) in a multicenter retrospective study from China and Russia. Methods: The retrospective multicenter study was conducted at three centers between January 2015 and December 2017. Relevant collected data included patient demographics, operative parameters, and postoperative complications. All procedures were performed using either a NOSES or a CLR approach. Results: The data of a total of 768 consecutive patients with rectal cancer were retrospectively analyzed, including 412 CLR and 356 NOSES cases. The two groups were comparable for all demographics and characteristics except for the median tumor size (P = 0.038). No difference was found in the operative time and number of retrieved lymph nodes. Intraoperative complications and positive resection margins were nil in both groups. No difference was found in the time to first flatus (P = 0.150), time to first defecation (P = 0.084), length of postoperative hospital stay (P = 0.152), anastomotic leakage (P = 0.377), and intra-abdominal abscess (P = NA). The CLR group but not the NOSES group had incisional hernia or wound infection events, although the difference between groups was not significant (P = 0.253). Conclusions: The NOSES procedure is a well-established strategy and may be considered as an alternative procedure to CLR for rectal cancer. However, the long-term benefits of this approach require further evaluation.
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Highly efficient pumpkin-seed extraction with the simultaneous recovery of lipophilic and hydrophilic compounds
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01.09.2019 |
Ferreira D.
Barin J.
Binello A.
Veselov V.
Cravotto G.
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Food and Bioproducts Processing |
10.1016/j.fbp.2019.07.014 |
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© 2019 Institution of Chemical Engineers Enabling technologies have led to the design of new extraction protocols for naturally occurring compounds that are fast, sustainable and have low energy demands. Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) have been used, in this study, for the recovery of valuable nutraceuticals and primary metabolites from pumpkin seeds (Curcubita sp.) and have been compared with conventional methods. In order to optimise extraction parameters and conditions, we have compared yields, total phenolic content, antioxidant activity, as well as fatty-acid and lipid profiles. The best yield, in both lipophilic and hydrophilic compounds, was achieved under UAE with a ternary solvent mixture (hexane/ethanol/water - 30:49:21). However, the highest phenolic content and antioxidant capacity were obtained using MAE under subcritical conditions with good extraction yields. The oil composition, as obtained using GC-FID analyses, showed a prevalence for unsaturated fatty acids; mainly linoleic and oleic acids. The use of UAE with ternary mixtures presented the highest lipid content and a slightly higher percentage of unsaturated compounds. Preliminary tests to verify the scalability of UAE with a ternary mixture showed that the extraction performance was maintained when using larger volumes (factor 10). This study will pave the road for the potential exploitation of UAE as a fast and efficient procedure for the simultaneous recovery of lipophilic and hydrophilic compounds from pumpkin seeds.
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Assessment of the stability of practical support of breastfeeding in a department of neonatal and premature infant pathology of a paediatric hospital
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01.01.2018 |
Abol’yan L.
Polyanskaya S.
Murzina E.
Novikova S.
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Voprosy Detskoi Dietologii |
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© 2018, Dynasty Publishing House. All rights reserved. The objective. Assessment of the practice of breastfeeding support in a department of neonatal and premature infant pathology of the Tambov Regional Children’s Clinical Hospital (TRCCH) after 3–4 years of becoming a WHO/UNICEF Baby Friendly Hospital. Patients and methods. Mothers were questioned using specially designed questionnaires at their admission to the department and at discharge from hospital. Overall, 356 mothers were questioned at admission and 327 at discharge. The results were processed on the SPSS.19 statistical programme. Frequency distribution, mean values (± standard deviation) and Student’s t-coefficient were determined. Results. The practice of supporting breastfeeding in the department consisted in observance of the 10 steps of successful breastfeeding: mother and infant remaining together (98.2%), breastfeeding on an infant’s demand (91.3%), breastfeeding at night (98.6%), breast milk extraction for infant feeding and lactation stimulation (88.6%), informing mothers about the benefits and technique of breastfeeding (90.5%). The percentage of breastfed infants significantly increased by the time of discharge from the department – to 89.4% (at admission – 71.9%; p < 0.0001), among them exclusively breastfed infants – to 66.5% (at admission – 45.3%; p < 0.0001). Conclusion. The practice of breastfeeding based on current international recommendations is successfully supported in the neonatal department of TRCCH. Nevertheless, breastfeeding parameters might be considerably improved due to attainment of continuity in the work of maternity clinics and TRCCH and optimization of the practices of breast milk extraction, storage and use in the department.
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Determination of cotinine in urine and wastewaters by high performance liquid chromatography coupled with tandem mass-spectrometric detection
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01.01.2018 |
Jang M.
Pirogov A.
Maksimova A.
Dobrovolskiy V.
Stakheev A.
Abramova J.
Priadka A.
Jaricov A.
Nosyrev A.
Rozhanets V.
Shpigun O.
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Moscow University Chemistry Bulletin |
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© Allerton Press, Inc., 2018. A technique of extracting cotinine in urine and wastewaters, followed by its quantitative determination, using high performance liquid chromatography combined with tandem mass-spectrometric detection is presented. The method is characterized by low detection limits and high levels of efficiency and sensitivity. The optimal conditions for the solid-phase extraction of cotinine from urine and wastewaters are found. This technique makes it possible to reliably estimate the content of cotinine in the urine of active and passive smokers and in wastewaters.
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Immediate implant placement into fresh extraction sites using single-drilling bur and two loading procedures: Follow-up results
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01.01.2018 |
Bettach R.
Taschieri S.
Mortellaro C.
Del Fabbro M.
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Journal of Craniofacial Surgery |
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Copyright © 2018 by Mutaz B. Habal, MD. Modern clinical protocols in implantology aim at shortening the treatment time and reducing duration and discomfort of the surgical phase, while maintaining optimal treatment outcomes. The purpose of this study was to evaluate clinical outcomes of implants immediately placed in extraction sites, using a single drilling step for implant site preparation. One-hundred thirty-three patients (mean age 55.3 ± 12.7 [SD] years, range 20 – 83 years) were treated at 2 clinical centers. Two-hundred sixty-one implants were inserted in fresh postextraction sockets. One-hundred sixty-five implants were immediately loaded (IL) and 96 underwent delayed loading (DL). Implant survival, peri-implant bone level change and patients’ satisfaction were assessed after at least 3 years of function. No patient dropout occurred. The mean follow-up was 63.61 ± 11.52 months (range 39.71 – 85.71 months) from prosthesis delivery. Two IL and 1 DL implant failed in 3 patients. Implant survival was 98.8% and 99% for IL and DL group, respectively. The mean marginal bone loss after 1 year was 0.48 ± 0.40 mm and 0.52 ± 0.34 mm for IL and DL group. No biological nor mechanical complications occurred. All patients demonstrated full satisfaction. The present protocol with single burs for site preparation produced satisfactory clinical outcomes independent of the loading timing. Further long-term comparative studies are needed to confirm the present findings.
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