scholarly journals Clean and Feasible Utilization of High Silica Fluorspar Powder via Reverse Flotation: A Pilot Study

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 555
Author(s):  
Chenhu Zhang ◽  
Jiande Gao ◽  
Yuehua Hu ◽  
Wei Sun ◽  
Fei Lv ◽  
...  
Keyword(s):  
Large Scale ◽  
Acid Leaching ◽  
Economic Benefits ◽  
Solution Chemistry ◽  
Low Grade ◽  
Aluminum Fluoride ◽  
Pilot Test ◽  
Reverse Flotation ◽  
Spectroscopy Analysis ◽  
High Silica

Fluorite is a nonrenewable mineral used to produce anhydrous hydrofluoric acid (AHF) and aluminum fluoride. The demand for low-grade fluorite powder (CaF2 < 97%) has fallen sharply owing to the current market conditions. Therefore, a large number of fluorite concentrates have been improved by acid leaching. While this approach can efficiently remove CaCO3 from fluorite concentrate, the SiO2 content, which significantly affects AHF consumption during the production of HF or aluminum fluoride, cannot be completely removed. To solve this problem, in this study, we used reverse flotation before leaching the fluorite concentrates. Subsequently, the feasibility of reverse flotation desilication was determined. The obtained results of the ZP (zeta potential) measurements, solution chemistry analysis, FTIR (Fourier transform infrared spectroscopy) analysis, and micro-flotation tests indicated that employing dodecylamine as the collector and citric acid as the depressor could effectively separate sericite from fluorite. The batch flotation experiment and the pilot test were conducted in Chenzhou (Hunan, China) followed by their operation in Xinyuan Mining Co. Ltd., which produces monolithic fluorite ore on the large scale in Asia. Notably, we found that the contents of both SiO2 and Al2O3 were from 2.82%, 1.17% reduced to 1.28%, 0.74% in the batch flotation experiment. The results of the pilot test showed that the new reverse flotation + leaching technology could dramatically reduce the potential environmental impact and costs, thereby significantly improving the economic benefits by satisfying the requirements of the market.

Screening for the FV: Q506 Mutation – Evaluation of Thirteen Plasma-based Methods for their Diagnostic Efficacy in Comparison with DNA Analysis

1997 ◽  
Vol 77 (03) ◽  
pp. 436-439 ◽  
Author(s):  
Armando Tripodi ◽  
Barbara Negri ◽  
Rogier M Bertina ◽  
Pier Mannuccio Mannucci
Keyword(s):  
Venous Thrombosis ◽  
Large Scale ◽  
Dna Analysis ◽  
Genetic Defect ◽  
Laboratory Diagnosis ◽  
Economic Benefits ◽  
Factor V ◽  
Factor X ◽  
Diagnostic Efficacy ◽  
Dna Test

SummaryThe factor V (FV) mutation Q506 that causes resistance to activated protein C (APC) is the genetic defect associated most frequently with venous thrombosis. The laboratory diagnosis can be made by DNA analysis or by clotting tests that measure the degree of prolongation of plasma clotting time upon addition of APC. Home-made and commercial methods are available but no comparative evaluation of their diagnostic efficacy has so far been reported. Eighty frozen coded plasma samples from carriers and non-carriers of the FV: Q506 mutation, diagnosed by DNA analysis, were sent to 8 experienced laboratories that were asked to analyze these samples in blind with their own APC resistance tests. The APTT methods were highly variable in their capacity to discriminate between carriers and non-carriers but this capacity increased dramatically when samples were diluted with FV-deficient plasma before analysis, bringing the sensitivity and specificity of these tests to 100%. The best discrimination was obtained with methods in which fibrin formation is triggered by the addition of activated factor X or Russell viper venom. In conclusion, this study provides evidence that some coagulation tests are able to distinguish carriers of the FV: Q506 mutation from non-carriers as well as the DNA test. They are inexpensive and easy to perform. Their use in large-scale clinical trials should be of help to determine the medical and economic benefits of screening healthy individuals for the mutation before they are exposed to such risk factors for venous thrombosis as surgery, pregnancy and oral contraceptives.

Economic benefit of shale gas exploitation based on back propagation neural network

2020 ◽  
Vol 39 (6) ◽  
pp. 8823-8830
Author(s):  
Jiafeng Li ◽  
Hui Hu ◽  
Xiang Li ◽  
Qian Jin ◽  
Tianhao Huang
Keyword(s):  
Neural Network ◽  
Shale Gas ◽  
Bp Neural Network ◽  
Large Scale ◽  
Linear Prediction ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Economic Benefits ◽  
Gas Well ◽  
Well Production

Under the influence of COVID-19, the economic benefits of shale gas development are greatly affected. With the large-scale development and utilization of shale gas in China, it is increasingly important to assess the economic impact of shale gas development. Therefore, this paper proposes a method for predicting the production of shale gas reservoirs, and uses back propagation (BP) neural network to nonlinearly fit reservoir reconstruction data to obtain shale gas well production forecasting models. Experiments show that compared with the traditional BP neural network, the proposed method can effectively improve the accuracy and stability of the prediction. There is a nonlinear correlation between reservoir reconstruction data and gas well production, which does not apply to traditional linear prediction methods

scholarly journals Solving the Real Power Limitations in the Dynamic Economic Dispatch of Large-Scale Thermal Power Units under the Effects of Valve-Point Loading and Ramp-Rate Limitations

2021 ◽  
Vol 13 (3) ◽  
pp. 1274
Author(s):  
Loau Al-Bahrani ◽  
Mehdi Seyedmahmoudian ◽  
Ben Horan ◽  
Alex Stojcevski
Keyword(s):  
Large Scale ◽  
Thermal Power ◽  
Optimization Technique ◽  
Economic Dispatch ◽  
Pso Algorithm ◽  
Search Space ◽  
Economic Benefits ◽  
Optimization Techniques ◽  
Ramp Rate ◽  
Dynamic Economic Dispatch

Few non-traditional optimization techniques are applied to the dynamic economic dispatch (DED) of large-scale thermal power units (TPUs), e.g., 1000 TPUs, that consider the effects of valve-point loading with ramp-rate limitations. This is a complicated multiple mode problem. In this investigation, a novel optimization technique, namely, a multi-gradient particle swarm optimization (MG-PSO) algorithm with two stages for exploring and exploiting the search space area, is employed as an optimization tool. The M particles (explorers) in the first stage are used to explore new neighborhoods, whereas the M particles (exploiters) in the second stage are used to exploit the best neighborhood. The M particles’ negative gradient variation in both stages causes the equilibrium between the global and local search space capabilities. This algorithm’s authentication is demonstrated on five medium-scale to very large-scale power systems. The MG-PSO algorithm effectively reduces the difficulty of handling the large-scale DED problem, and simulation results confirm this algorithm’s suitability for such a complicated multi-objective problem at varying fitness performance measures and consistency. This algorithm is also applied to estimate the required generation in 24 h to meet load demand changes. This investigation provides useful technical references for economic dispatch operators to update their power system programs in order to achieve economic benefits.

scholarly journals Electrocatalysis for Oxygen Reduction Reaction on EDTAFeNa and Melamine co-Derived Self-Supported Fe-N-C Materials

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 623
Author(s):  
Mengfan Shen ◽  
Ziwei Meng ◽  
Tong Xue ◽  
Hongfang Shen ◽  
Xiang-Hui Yan
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Large Scale ◽  
Acid Leaching ◽  
Reduction Reaction ◽  
Scale Production ◽  
Final Annealing ◽  
High Performing ◽  
Half Wave ◽  
Mesoscopic Structure

To explore high-performing alternatives to platinum-based catalysts is highly desirable for lowering costs and thus promoting fuel cell commercialization. Herein, self-supported Fe-N-C materials were prepared by the pyrolysis of dual precursors including EDTA ferric sodium (EDTAFeNa) and melamine (MA), followed by acid-leaching and final annealing. Towards an oxygen reduction reaction (ORR) in 0.1 M KOH, the as-prepared MA/EDTAFeNa-HT2 delivered onset (Eonset) and half-wave (E1/2) potentials of 0.97 and 0.84 V vs. RHE, respectively, identical with that of a state-of-the-art Pt/C catalyst, accompanied with predominantly a four-electron pathway. The introduction of MA and extension of acid-leaching promoted a positive shift of 50 mV for E1/2 relative to that of only the EDTAFeNa-derived counterpart. It was revealed that the enhancement of ORR activity is attributed to a decrease in magnetic Fe species and increase in pyridinic/quanternary nitrogen content whilst nearly excluding effects of the graphitization degree, variety of crystalline iron species, and mesoscopic structure. The usage of dual precursors exhibited great potential for the large-scale production of inexpensive and efficient Fe-N-C materials.

Evaluation of Acid Leaching of Low Grade Chalcopyrite Using Ozone by Statistical Analysis

2010 ◽  
Vol 49 (3) ◽  
pp. 219-226 ◽  
Author(s):  
F. R. Carrillo-Pedroza ◽  
M. A. Sánchez-Castillo ◽  
M. J. Soria-Aguilar ◽  
A. Martínez-Luévanos ◽  
E. C. Gutiérrez
Keyword(s):  
Statistical Analysis ◽  
Acid Leaching ◽  
Low Grade

Study on the Concentration of a Carbon-Containing Oolitic Low-Grade Collophane

2014 ◽  
Vol 900 ◽  
pp. 681-684
Author(s):  
Wan Chao Jin ◽  
Ping Zhou ◽  
Hai Yun Xie ◽  
Wei Tan ◽  
Bo Wen Yang
Keyword(s):  
Low Grade ◽  
Reverse Flotation ◽  
Valuable Component

Apatite is a valuable component of the collophane taken from Yunnan, as it is in the shape of oolith and contains a lot of carbon, and hence an effective benefication of the apatite is difficult to be occurred by means of concentration. Based on the results of both direct and reverse flotation tests, it shows that reverse flotation is effective in the benefication of the apatite to a certain extent. When reverse flotation is employed to treat the run-of-mine at a grade of 18.77%, the concentrate containing P2O5 24.04% at a recovery of 62.58% can be produced.

1-D Model Analysis of Tesla Turbine for Small Scale Organic Rankine Cycle (ORC) System

2017 ◽  
Author(s):  
Jian Song ◽  
Chun-wei Gu
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Organic Rankine Cycle ◽  
Axial Flow ◽  
Rankine Cycle ◽  
Expansion Ratio ◽  
Working Fluid ◽  
Small Scale ◽  
Low Grade ◽  
D Model

Energy shortage and environmental deterioration are two crucial issues that the developing world has to face. In order to solve these problems, conversion of low grade energy is attracting broad attention. Among all of the existing technologies, Organic Rankine Cycle (ORC) has been proven to be one of the most effective methods for the utilization of low grade heat sources. Turbine is a key component in ORC system and it plays an important role in system performance. Traditional turbine expanders, the axial flow turbine and the radial inflow turbine are typically selected in large scale ORC systems. However, in small and micro scale systems, traditional turbine expanders are not suitable due to large flow loss and high rotation speed. In this case, Tesla turbine allows a low-cost and reliable design for the organic expander that could be an attractive option for small scale ORC systems. A 1-D model of Tesla turbine is presented in this paper, which mainly focuses on the flow characteristics and the momentum transfer. This study improves the 1-D model, taking the nozzle limit expansion ratio into consideration, which is related to the installation angle of the nozzle and the specific heat ratio of the working fluid. The improved model is used to analyze Tesla turbine performance and predict turbine efficiency. Thermodynamic analysis is conducted for a small scale ORC system. The simulation results reveal that the ORC system can generate a considerable net power output. Therefore, Tesla turbine can be regarded as a potential choice to be applied in small scale ORC systems.

A novel method for desulfurization and purification of fluorite concentrate using acid leaching and reverse flotation of sulfide

2019 ◽  
Vol 209 ◽  
pp. 1006-1015 ◽  
Author(s):  
Hang Liu ◽  
Sultan Ahmed Khoso ◽  
Wei Sun ◽  
Yangge Zhu ◽  
Haisheng Han ◽  
...  
Keyword(s):  
Acid Leaching ◽  
Reverse Flotation ◽  
Novel Method

scholarly journals Case Report: Efficacy of Pyrotinib in ERBB2 Amplification Pulmonary Adenoid Cystic Carcinoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Zhongben Tang ◽  
Feng Lin ◽  
Jiarong Xiao ◽  
Xiaojun Du ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Targeted Therapy ◽  
Adenoid Cystic Carcinoma ◽  
Large Scale ◽  
Case Reports ◽  
Growth Factor Receptor ◽  
Low Grade ◽  
Adenoid Cystic ◽  
Epidermal Growth ◽  
Low Incidence ◽  
Current Report

Primary pulmonary adenoid cystic carcinomas are salivary tumors that are low-grade malignant and prone to recurrence and metastasis. Surgery is currently the main treatment, but there is no standard with regard to postoperative adjuvant therapy. Adenoid cystic carcinoma is more sensitive to radiotherapy and patients benefit less from chemotherapy, but few studies have focused on targeted therapy, and their conclusions are inconsistent. With respect to primary pulmonary adenoid cystic carcinoma, large-scale studies cannot be conducted due to its low incidence, and studies on the targeted therapy of it are very scarce. A few case reports indicate that targeted therapy can be effective however, suggesting that it may be a good option. The current report is the first on the occurrence of human epidermal growth factor receptor 2 amplification in pulmonary adenoid cystic carcinoma. The patient was treated with pyrotinib for 6 months and achieved stable disease.

scholarly journals Cost-Effectiveness Analysis of a Large-Scale Crèche Intervention to Prevent Child Drowning in Rural Bangladesh

2021 ◽  
Author(s):  
Y. Natalia Alfonso ◽  
Adnan A Hyder ◽  
Olakunle Alonge ◽  
Shumona Sharmin Salam ◽  
Kamran Baset ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Societal Perspective ◽  
Large Scale ◽  
Operating Cost ◽  
Cost Effective ◽  
Economic Benefits ◽  
Program Cost ◽  
Rural Bangladesh ◽  
Life Years ◽  
The Cost

Abstract Drowning is the leading cause of death among children 12-59 months old in rural Bangladesh. This study evaluated the cost-effectiveness of a large-scale crèche intervention in preventing child drowning. Estimates of the effectiveness of the crèches was based on prior studies and the program cost was assessed using monthly program expenditures captured prospectively throughout the study period from two different implementing agencies. The study evaluated the cost-effectiveness from both a program and societal perspective. Results showed that from the program perspective the annual operating cost of a crèche was $416.35 (95%C.I.: $222 to $576), the annual cost per child was $16 (95%C.I.: $9 to $22) and the incremental-cost-effectiveness ratio (ICER) per life saved with the crèches was $17,803 (95%C.I.: $9,051 to $27,625). From the societal perspective (including parents time valued) the ICER per life saved was -$176,62 (95%C.I.: -$347,091 to -$67,684)—meaning crèches generated net economic benefits per child enrolled. Based on the ICER per disability-adjusted-life years averted from the societal perspective (excluding parents time), $2,020, the crèche intervention was cost-effective even when the societal economic benefits were ignored. Based on the evidence, the creche intervention has great potential for reducing child drowning at a cost that is reasonable.

Sign in / Sign up

Export Citation Format

Share Document