scholarly journals A Case Study of Enhanced Sulfidization Flotation of Lead Oxide Ore: Influence of Depressants

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 95
Author(s):  
Haiyun Xie ◽  
Rui Sun ◽  
Jizong Wu ◽  
Dongxia Feng ◽  
Likun Gao
Keyword(s):  
Lead Oxide ◽  
Open Circuit ◽  
Bench Test ◽  
Infrared Spectrometry ◽  
Experimental Conditions ◽  
Function Mechanism ◽  
Lead Metal ◽  
Special Value ◽  
Flotation Method

The refractory lead oxide ore has become an important source of lead metal with the continuous depletion of lead sulfide minerals. Lead oxide ore is of poor floatability and there are few cases to concentrate it successfully. In this study, the sulfidization-xanthate flotation method is applied for the beneficiation of lead oxide ore in Yunnan Province (China) with sodium hexametaphosphate and carboxymethyl cellulose as depressant. Chemical analysis and phase analysis was performed to explore the physicochemical property of raw ore, which provides a research basis for process design and operational control. The main influencing factors during the process, including grinding fineness, reagent types, and dosage, etc., have been studied through flotation tests. Zeta potential measurements and Fourier transfer-infrared spectrometry (FTIR) analysis were conducted to reveal the function mechanism of the reagents. Based on the determined experimental conditions, open circuit tests and closed circuit tests with one stage rougher, three-stage scavenger, and two-stage cleaner flotation, were carried out with the run-of-mine ore with a lead grade of 4.57%. Through close circuit bench test, the lead concentrate with a lead grade of 64.08% and recovery of 92.30% was obtained. This study is of special value, as it provides referencing significance for economically exploiting lead oxide ore.

Structure and Resistance to Electrochemical Corrosion of NiTi Alloy

2013 ◽  
Vol 203-204 ◽  
pp. 335-338 ◽  
Author(s):  
Bożena Łosiewicz ◽  
Magdalena Popczyk ◽  
Tomasz Goryczka ◽  
Józef Lelątko ◽  
Agnieszka Smołka ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Niti Alloy ◽  
Electrochemical Corrosion ◽  
High Resolution Electron Microscopy ◽  
Potential Method ◽  
Passive Layer ◽  
Open Circuit ◽  
Experimental Conditions ◽  
Electrochemical Tests ◽  
Reflectivity Method

The NiTi alloy (50.6 at.% Ni) passivated for 30 min at 130°C by autoclaving has been studied towards corrosion resistance in aqueous solutions of 3% NaCl, 0.1 M H2SO4, 1 M H2SO4 and HBSS. Structure and thickness of the passive layer (TiO2, rutile) were examined by X-ray reflectivity method and high resolution electron microscopy. Corrosion behavior of this oxide layer was investigated by open circuit potential method and polarization curves. It was found that the corrosion resistance of the passivated NiTi alloy is strongly dependent on the type of corrosive environment. The higher corrosion resistance of the tested samples was revealed in sulfate solutions as compared to chloride ones. The highest resistance to electrochemical corrosion of the NiTi alloy was observed in 0.1 M H2SO4 solution. Susceptibility to pitting corrosion of the tested samples was observed which increased with the concentration rise of chlorine anions in solution. Electrochemical tests for 316L stainless steel carried out under the same experimental conditions revealed a weaker corrosion resistance in all solutions as compared to the highly corrosion resistant NiTi alloy.

Dispersion of TiO2 Nanotubes in a Chitosan Matrix

MRS Advances ◽  
2018 ◽  
Vol 3 (63) ◽  
pp. 3805-3810
Author(s):  
B. Núñez Mendoza ◽  
S.R. Vasquez-García ◽  
N. Flores-Ramírez ◽  
J. L. Rico ◽  
L. Zamora Peredo ◽  
...  
Keyword(s):  
Electrochemical Anodization ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Second Stage ◽  
Chitosan Matrix ◽  
Third Stage ◽  
Membrane Type ◽  
Titanium Foils

ABSTRACTThis work presents the synthesis and characterization of TiO2 nanotubes (NTT) with chitosan (CS). In a first stage, electrochemical anodization of titanium foils was used to generate NTT in a membrane-type arrangement. From these experiments, suitable experimental conditions were selected. In a second stage, the synthesized NTT were detached from the titanium foils by sonication. In the third stage, the detached NTT were dispersed in an acid solution containing CS in various concentrations. Finally, the nanotubes-chitosan (NTT/CS) samples were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectrometry (FTIR). Our results showed that the NTT presented very regular tube morphology with -OH and Ti-O- functional groups on the surface. The interaction of NTT and chitosan was enhanced by increasing the time of contact during the synthesis of the titanium composites.

scholarly journals Computational Design of Sensitized Combustion Chemistry Experiments

2021 ◽  
Vol 7 ◽  
Author(s):  
Cody Ising ◽  
Pedro Rodriguez ◽  
Daniel Lopez ◽  
Jeffrey Santner
Keyword(s):  
Shock Tube ◽  
Initial Conditions ◽  
Computational Design ◽  
Reaction Rates ◽  
Oxidation Reactions ◽  
Combustion Chemistry ◽  
Experimental Conditions ◽  
As Species ◽  
User Friendly

In combustion chemistry experiments, reaction rates are often extracted from complex experiments using detailed models. To aid in this process, experiments are performed such that measurable quantities, such as species concentrations, flame speed, and ignition delay, are sensitive to reaction rates of interest. In this work, a systematic method for determining such sensitized experimental conditions is demonstrated. An open-source python script was created using the Cantera module to simulate thousands of 0D and hundreds of 1D combustion chemistry experiments in parallel across a broad, user-defined range of mixture conditions. The results of the simulation are post-processed to normalize and compare sensitivity values among reactions and across initial conditions for time-varying and steady-state simulations, in order to determine the “most useful” experimental conditions. This software can be utilized by researchers as a fast, user-friendly screening tool to determine the thermodynamic and mixture parameters for an experimental campaign. We demonstrate this software through two case studies comparing results of the 0D script against a shock tube experiment and results of the 1D script against a spherical flame experiment. In the shock tube case study we present mixture conditions compared to those used in the literature to study H + O2 (+M)→HO2(+M). In the flame case study, we present mixture conditions compared to those in the literature to study formyl radical (HCO) decomposition and oxidation reactions. The systematically determined experimental conditions identified in the present work are similar to the conditions chosen in the literature.

scholarly journals Adsorption of Deoxynivalenol (DON) from Corn Steep Liquor (CSL) by the Microsphere Adsorbent SA/CMC Loaded with Calcium

Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 208
Author(s):  
Ahmed Shalapy ◽  
Shuangqing Zhao ◽  
Chenxi Zhang ◽  
Yifei Li ◽  
Hairong Geng ◽  
...  
Keyword(s):  
Animal Feed ◽  
Physical Adsorption ◽  
Corn Steep Liquor ◽  
Reaction Times ◽  
Deionized Water ◽  
Infrared Spectrometry ◽  
Batch Experiments ◽  
Experimental Conditions ◽  
Carboxymethyl Cellulose Sodium ◽  
Steep Liquor

The occurrence of deoxynivalenol (DON) in animal feed is a serious issue for the livestock industry. Approaches using mycotoxin adsorbents are key to decreasing mycotoxin carryover from contaminated feed to animals. In this paper, a novel functional microsphere adsorbent comprising an alginate/carboxymethyl cellulose sodium composite loaded with calcium (SA/CMC-Ca) was prepared by an emulsification process to adsorb DON from polluted corn steep liquor (CSL) containing DON at a concentration of 3.60 μg/mL. Batch experiments were conducted under different experimental conditions: CSL volumes, reaction times, desorption times, and microsphere recyclability. Results showed that 5 g of microspheres reacted with 5 mL of DON-polluted CSL for 5 min, the microspheres can be recycled 155 times, and the maximum DON adsorption for the microspheres was 2.34 μg/mL. During recycling, microspheres were regenerated by deionized water every time; after the microspheres were cleaned, DON in the deionized water was degraded by sodium hydroxide (NaOH) at 70 °C for 1 h at pH 12. The mechanism for physical adsorption and hydrogen bonding was analyzed by scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR). To the best of our knowledge, this is the first report showing that the microsphere adsorbent SA/CMC-Ca adsorbs DON. Therefore, we suggest that using microsphere absorbents would be a possible way to address DON-contaminated CSL issues in animal feed.

Numerical simulations of non-stationary distributions of electrochemical potentials in SOFC

2017 ◽  
Vol 34 (6) ◽  
pp. 1956-1988 ◽  
Author(s):  
Mayu Muramatsu ◽  
Keiji Yashiro ◽  
Tatsuya Kawada ◽  
Kenjiro Tarada
Keyword(s):  
Steady State ◽  
Numerical Simulations ◽  
Chemical Potential ◽  
Simulation Method ◽  
Open Circuit ◽  
Operating Conditions ◽  
Stationary Distributions ◽  
Experimental Conditions ◽  
Content Type ◽  
Numerical Examples

Purpose The purpose of this study is to develop a simulation method to calculate non-stationary distributions of the chemical potential of oxygen in a solid oxide fuel cell (SOFC) under operation. Design/methodology/approach The initial-boundary value problem was appropriately formulated and the appropriate boundary conditions were implemented so that the problem of non-stationary behavior of SOFC can be solved in accordance with actual operational and typical experimental conditions. The dependencies of the material properties on the temperature and partial pressure of oxygen were also elaborately introduced to realize actual material responses. The capability of the proposed simulation method was demonstrated under arbitrary operating conditions. Findings The steady state calculated with the open circuit voltage condition was conformable with the analytical solution. In addition, the transient states of the spatial distributions of potentials and currents under the voltage- and current-controlled conditions were successfully differentiated, even though they eventually became the same steady state. Furthermore, the effects of dense materials assumed for interconnects and current collectors were found to not be influential. It is thus safe to conclude that the proposed method enables us to simulate any type of transient simulations regardless of controlling conditions. Practical implications Although only uniaxial models were tested in the numerical examples in this paper, the proposed method is applicable for arbitrary shapes of SOFC cells. Originality/value The value of this paper is that adequate numerical simulations by the proposed method properly captured the electrochemical transient transport phenomena in SOFC under various operational conditions, and that the applicability was confirmed by some numerical examples.

scholarly journals Microbial flocculant produced by a novel Paenibacillus sp., strain A9, using food processing wastewater to replace fermentation medium and its application for the removal of Pb(II) from aqueous solution

2019 ◽  
Vol 37 (9-10) ◽  
pp. 683-697 ◽  
Author(s):  
Binhui Jiang ◽  
Lili Fu ◽  
Wan Cao ◽  
Bo Zhang ◽  
Fengda Li ◽  
...  
Keyword(s):  
Cell Surface ◽  
Fermentation Broth ◽  
Removal Rate ◽  
Production Costs ◽  
Infrared Spectrometry ◽  
Bacterial Cells ◽  
Experimental Conditions ◽  
Spectrometry Analysis ◽  
Paenibacillus Sp ◽  
Food Wastewater

Due to high production costs, the popularization and application of microbial flocculants in the field of water treatment have been limited. In this study, the capture of lead ions by the fermentation broth of a novel Paenibacillus sp. strain A9 and cultured with food wastewater was further investigated. The results revealed that the production of MBFA9 could be increased significantly by adding a small amount of carbon and nitrogen to food wastewater. Under the best experimental conditions (pH 8.5, culture temperature 30°C, 150 r/min), adding 1% (m/v) carbon and 0.1% (m/v) nitrogen to 1% (v/v) wastewater resulted in a yield of MBFA9 of 6.29 g/l. At a temperature of 30°C, pH of 5, contact time of 35 min, and FBA9 dosage of 5%, the removal rate and removal capacity of Pb(II) reached the highest values of 95.1% and 317 mg/g, respectively. Field emission scanning electron microscopy analysis indicated that bacterial cells, metabolite small molecule acids, and MBFA9 in FBA9 all contributed to the removal of Pb(II). Fourier-transform infrared spectrometry analysis indicated that functional groups such as –OH, –COOH, –CO, and –NH2 existed in MBFA9 and on the cell surface. Various mechanisms involved in Pb(II) removal can occur simultaneously, including cell surface adsorption, microcrystallization, and biological flocculation.

Matrix Isolation/Fourier Transform Infrared Spectrometry of Laser-Desorbed Species

1995 ◽  
Vol 49 (7) ◽  
pp. 955-963 ◽  
Author(s):  
B. L. Carr ◽  
R. S. Brown
Keyword(s):  
Fourier Transform ◽  
Carbon Dioxide Laser ◽  
Matrix Isolation ◽  
Sinapinic Acid ◽  
Laser Desorption ◽  
Fourier Transform Infrared ◽  
Maldi Mass Spectrometry ◽  
Infrared Spectrometry ◽  
Coumaric Acid ◽  
Experimental Conditions

Initial results are presented for a novel experimental arrangement which allows the successful study of laser-desorbed neutral species under matrix isolation conditions. In the current work, a pulsed carbon dioxide laser (10.6 μm) is employed for laser desorption. With the combination of a previously described cryogenic trapping technique with coaxial matrix isolation gas (xenon or argon) introduction, laser-desorbed neutrals have been matrix isolated and their Fourier transform infrared spectra recorded. Two different cinnamic acid derivatives ( p-coumaric acid and sinapinic acid) typically employed for matrix-assisted laser ionization (MALDI) mass spectrometry were utilized to demonstrate this new technique. Experimental conditions were determined for optimal matrix isolation of the laser-desorbed species. Two different desorption geometries were examined with respect to their effectiveness for matrix isolation of desorbed neutrals. A covalent dimer of p-coumaric acid produced in an external UV photoreactor and thought to be a possible photoreaction product in UV MALDI was studied by this technique. Thermal degradation of this dimer is shown to occur above threshold irradiance for laser desorption.

Knowledge Management Values of Al-Ta’alum\In Ms 1900:2005 Quality Management System: A Case Study of Kolej of Islam Pahang Sultan Ahmad Shah (Kipsas)

2015 ◽  
Vol 21 (4) ◽  
pp. 676-679
Author(s):  
Muhammad Hafiz Yaakub ◽  
Ali Fauzi Ahmad Khan ◽  
Ishak Ismail
Keyword(s):  
Knowledge Management ◽  
Knowledge Sharing ◽  
Quality Management System ◽  
System A ◽  
Knowledge Sharing Behavior ◽  
Exploratory Approach ◽  
Special Value ◽  
And Gender ◽  
Sharing Behavior

This study aims to evaluate the willingness of knowledge sharing and acquisition behaviors among KIPSAS’s employees to comply with the values of Al-Ta’allum. These are aligned with the principles of knowledge management. The main objective is to identify the differences in knowledge sharing of the staff with their knowledge acquisition behavior. Thus, identifying the state of readiness among staff. This study utilizes an exploratory approach to examine these phenomena. Related documents were analyzed to get an overview of the factors and values of Al-Ta’allum that have been identified and examined within the study. Questionnaires were sent to 129 respondents from academic and non-academic staffs. But only 62 responses were gathered. There were also differences when the respondents were divided and analyzed according to responsibilities and gender. Within the context of this article, we found the overall relevance of values stipulated in Al-Ta’allum to staff of KIPSAS. This study is concerned with examining the knowledge sharing behavior of staff in a PHEI. It highlights the differences in their knowledge sharing and acquisition behavior. This allows management and planner of such institutions to plan the Knowledge Management (KM) initiatives and processes with these special value indicators such as Al-Ta’allum to be taken into consideration. Based on the result, KIPSAS is able to manage knowledge sharing activities in a more effective method.

The Death of Anna Katharina Ehmer: A Case Study in Terminal Lucidity

2014 ◽  
Vol 68 (1) ◽  
pp. 77-87 ◽  
Author(s):  
Michael Nahm ◽  
Bruce Greyson
Keyword(s):  
Background Information ◽  
Mental Disabilities ◽  
Single Word ◽  
Brain Functioning ◽  
The Past ◽  
Neurologic Disorders ◽  
Chief Physician ◽  
Special Value ◽  
Peculiar Phenomenon

Terminal lucidity, the unexpected return of mental clarity and memory shortly before the death of patients suffering from severe psychiatric and neurologic disorders, has raised the curiosity of numerous physicians and laypersons in the past. However, this peculiar phenomenon has received little attention in the recent decades. In previous publications, we have presented overviews of cases of terminal lucidity in various neurologic and psychiatric disorders. In this article, we highlight terminal lucidity in persons with mental disabilities, and focus on one of the most remarkable cases that have been reported. We provide biographical background information about the two principal witnesses who reported this case. It concerns the death of Anna Katharina Ehmer, a 26-year-old woman with severe mental disabilities who lived in an institution for people with mental disorders, and who had allegedly never spoken a single word during her life. Yet, she was reported to have sung dying songs for a half hour before she died. The case was reported by the head of this institution and by its chief physician. We consider it difficult to evaluate the authenticity of the case definitively in retrospect. Nevertheless, there are similar cases and a variety of other anomalous brain-related findings we consider worth investigating. Studies into such anomalous cases might improve our concepts of human brain functioning and of mental processing in persons with mental disabilities, and might be of special value for the dying, the bereaved, and caretakers.

Sign in / Sign up

Export Citation Format

Share Document