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Complexation extraction of scheelite and transformation behaviour of tungsten-containing phase using H_(2)SO_(4) solution with H_(2)C_(2)O_(4) as complexing agent

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Transactions of Nonferrous Metals Society of China 2021年第10期31卷 3150-3161页

作者： Qing-sheng LIU Tao TU Hao GUO Hua-jin CHENG Xue-zhong WANG Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China Mechanical and Electrical Engineering Department Gannan University of Science and TechnologyGanzhou 341000China School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China

The extraction of tungsten from scheelite was carried out using a sulfuric acid solution with oxalic acid as the chelating *** was obtained in the form of highly soluble hydrogen aqua oxalato tungstate H_(2)[WO_(3)(C_(2)O_(4))·H_(2)O] during the leaching process,while calcium remained in the residue as calcium sulfate dihydrate(CaSO4·2H2O).About 99.2%of the tungsten was leached at 70℃,1.5 mol/L sulfuric acid,1 mol/L oxalic acid,a liquid/solid ratio of 25:1(mL/g),an oxalic acid to sulfuric acid molar ratio of 1:1,a stirring speed of 300 r/min and a leaching time of 2 h.H_(2)[WO_(3)(C_(2)O_(4))·H_(2)O]was thermally decomposed into tungstic acid(H_(2)WO_(4)),and tungsten trioxide(WO_(3))was directly produced by calcining H_(2)WO_(4) at 700℃ for 2 *** surface chemical reaction was determined to be the controlling step during tungsten leaching,and the apparent activation energy was calculated to be 51.43 kJ/mol.

关键词： scheelite kinetics chemical reaction oxalic acid sulfuric acid

Investigation of Aloe lateritia Gel as Corrosion Inhibitor for Mild Steel in 2 M HNO₃ and 1 M H₂SO₄ Media

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Journal of Minerals and Materials Characterization and Engineering 2016年第1期4卷 33-39页

作者： Lucas Paul Revocatus L. Machunda Department of Materials and Energy Science & Engineering Nelson Mandela African Institution of Science and Technology Arusha Tanzania Department of Water and Environmental Science and Engineering Nelson Mandela African Institution of Science and Technology Arusha Tanzania

Corrsion inhibition of Aloe lateritia gel for Mild steel in 2 M HNO3 and 1 M H2SO4 solutions was investigated by potentiodynamic polarization, Scanning electron microscopy (SEM) and Foutier transform infrared (FT-IR). Inhibition efficiency increased with the increase of the concentration of the gel. The optimal concentration of the gel gives maximum inhibition efficiency of 77.4% and 70.3% in 1 M H2SO4 and 2 M HNO3 respectively. Polarization plots shows that, the gel works as a mixed type inhibitor altering both cathodic and anodic reaction. SEM proves the uniform and pitting corrosion at the surface of Mild steel in 1 M H2SO4 and 2 M HNO3 respectively. Using FT-IR potential function groups from pure gel and some stretch shift was observed from corrosion product and some stretch shift from corrosion products was observed.

关键词： Corrosion Inhibitor Mild Steel Potentiodynamic Polarization sulfuric acid Nitric acid

Effect of Pre-Sowing Treatments on Mamalis (Pittosporum pentandrum Blanco Merr.) Seeds Germination under Nursery Condition

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Open Journal of Ecology 2023年第2期13卷 106-118页

作者： Raffy L. Tano College of Agriculture Forestry and Environmental Sciences Aklan State University Banga Philippines

Seeds were subjected to three different pre-sowing seed treatments: immersion in lukewarm water for 2 hours, immersion in concentrated sulfuric acid (H2SO4) for 5 minutes, hilar removal, and a control in which the seeds were sown without being treated. The experiment was laid out in the Completely Randomized Design (CRD) with four replicates and 60 seeds per treatment. Seeds were sown in an improvised Seedbox in October 2019. Germination was monitored daily for one month. The results showed that Mamalis seeds treated with lukewarm water have the earliest germination of twelve days, with a germination percentage of 66.67%. The germination rate of another treatment ranges from 0 - 44 percent, compared to 45 percent for the control treatment. It seems prudent to conclude that to enhance the vegetative propagation methods is to soaking in warm water at 37.5˚C for 2 hours could provide the best growth.

关键词： Pittosporum pentandrum Seed Germination Pre-Treatments sulfuric acid Seed Dormancy

Effect of Commercial Cellulase Enzymes on Ethanol Production from Pretreated Rice Straw at High Solid Loading

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Journal of Food Science and Engineering 2015年第2期5卷 67-75页

作者： Teerapatr Srinorakutara Yuttasak Subkaree Nassapat Boonvitthya Thapparait Kunhanon Nantana Bamrungchue Department of Energy Technology Thailand Institute of Scientific and Technological Research (TISTR) Pathum Thani 12120Thailand PTT Research and Technology Institute PTT Public Company Limited Ayutthaya 13170 Thailand

Effect of commercial cellulose enzymes was investigated by batch enzymatic hydrolysis at 15.0% （w/v） solid. It was found that the best commercial cellulose enzyme was Cellic（R） CTec comparing to Accellerase 1000TM and Accelerase 1500TM. The Cellic（R） CTec gave the highest reducing sugar concentration and rice straw conversion. Moreover, when the hydrolysate obtained from hydrolysis using Cellic（R） CTec was fermented by Saccharomyces cerevisiae TISTR 5596, it would give the highest ethanol. In this study, the Cellic（R） CTec was used for fed-batch prehydrolysis prior to ethanol production by simultaneous saccharification and fermentation （SSF） way at 20% （w/v） solid loading. It could produce 35.76 g/L or 4.6% （v/v） of ethanol concentration and 83.67 L/ton dry matter （DM） of yield.

关键词： Rice straw sulfuric acid commercial cellulase pretreatment fermentation ethanol.

Catalytic Esterification of Medium-Chain Fatty acids:Kinetic Investigations

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International Journal of Organic Chemistry 2017年第4期7卷 336-345页

作者： Maria Kulawska Maria Organek Wieslaw Organek Institute of Chemical Engineering Polish Academy of SciencesGliwicePoland Institute of Heavy Organic Synthesis Blachownia Kedzierzyn-KozlePoland

Medium-chain fatty acids (MCFA) are straight-chain fatty acids with aliphatic tails of 6 - 12 carbons, which can form medium-chain triglycerides. They are found mostly in animal fats and in the tropical vegetable oils. Because of their wide applications in industry, there is a growing demand of esters of medium-chain fatty acids production. The aim of our work was investigations of the kinetics of the synthesis of esters of MCFA in the presence of dowex catalyst in wide range of process parameters. Hexanoic, octanoic and decanoic acids were esterified with n-octyl alcohol in the presence of sulfuric acid and commercial dowex W50X8 as catalysts in an experimental semi-periodic glass tank reactor with instantaneous and complete water removal. Because of complete removal of water from the reacting mixture, thus eliminating the reverse hydrolysis reaction, the esterification can be assumed as irreversible reaction. The temperature range was 393 - 423 K, the range of initial mole ratio of alcohol to acid was 3 - 10. The kinetic parameters are given. The reaction kinetics appeared to be of the first order with respect to the acid. The effect of temperature on the reaction rate follows the Arrhenius equation well.

关键词： Decanoic acid Esterification Heterogenous Catalyst Hexanoic acid Octanoic acid Octyl Alcohol sulfuric acid

Durability of Recycled Concrete Aggregate in Aggressive Environments

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Journal of Civil Engineering and Architecture 2016年第10期10卷 1097-1102页

作者： Zainab Aamer Shamsulddin College of Engineering A Hraqia University Baghdad 10001 Iraq

The main purpose of this research is to study the durability of recycled concrete as a partial replacement of coarse aggregate in corrosive environment. 10%, 20%, 30% and 40% by weight were used for recycled concrete. Concrete samples exposed to 10% concentration dilute sulfuric acid solution for 180 days. Mechanical tests such as compressive and tensile strength tests, physical tests such as ultrasonic pulse velocity, bulk density, porosity, specific gravity and water absorption tests were done to the samples after curing in normal water for 28 days and after submerged in dilute sulfuric acid for 180 days. Degradation increased with increasing of replacement. Test results showed that 10% and 20% partial replacement of recycled concrete aggregate still closely to reference samples. Noticeable deterioration was shown in mechanical and physical properties for 30% and 40% partial replacement of recycled concrete aggregate.

关键词： Recycled concrete sulfuric acid compressive strength tensile strength durability partial replacement.

The Resolution of the Mysterious Plum Pox Phenomena Caused by Plum Pox Potyvirus

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Journal of Environmental Science and Engineering(A) 2013年第5期2卷 311-314页

作者： Vahida Seremet A. Seremeta 14-Tuzla 75000 Bosnia and Herzegovina

Plum pox potyvirus, also known as Sharka, is a disease of plum, first registered in Bulgaria, 100 years ago. The official scientific opinion is the plum tree should be cut, pulled out of the ground and not to plant anything in that place for five years. The research was directed at plants so the cause was sought in a virus considered to be cancer. However, a single phenomenon that, for instance, there is only a healthy plum tree among the infected ones, that it blossoms on a hill but not at the foot hill, and during the dry and rainy year, contributed to the fact that there are many dilemmas and mystifications in searching for the cause of the disease. New theory proves to be the cause of diseases lies in the soil i.e., in acid rains, that the disease could be cured and it is noncommunicable. At work ＂the resolution of mysterious plum pox phenomena caused by PPV＂ on the concrete examples, there were answers to all questions known to author during the specific period of time （during the war in Bosnia and Herzegovina）.

关键词： Mystery plum PPV sulfuric acid the cause non-communicability of disease.

Self Fluxing Electrolytes for High Speed Tin Electrodeposition

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Self Fluxing Electrolytes for High Speed Tin Electrodepositi...

The Transition from the Single Protonation to the Double Protonation: Theoretical Studies on the Clusters [(CH3)3N](H2SO4)(H2O)8-14

第十届中国钢铁年会暨第六届宝钢学术年会

作者： Levey Carol Global Marketing Manager Steel Mills Dow Chemical

Approximately 65% of tinplate lines are vertically oriented and utilize an electrolyte base consisting of phenol-sulfonic acid and ethoxylated naptholene sulfonic acid（PSA/ENSA）. A significant advantage of PSA/ENSA is that the diluted electrolyte can be used to facilitate fluxing of the tinplate. Replacement electrolytes, such as those based on the non-toxic and more environmentally sustainable methanesulfonic acid（MSA）, are considered non-self-fluxing and require a separate fluxing agent which adds to the financial and logistical burden during replacement as both conversion capital and tank allotment is typically limited. This paper describes a novel fluxing agent that can be used on MSA and sulfuric acid based electrolytes to permit operation in a self-fluxing configuration, simplifying both conversion and reducing cost of operation.

关键词： tinplate methanesulfonic acid self-fluxing sulfuric acid

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The Transition from the Single Protonation to the Double Pro...