scholarly journals Comparison of Alternative Strategies Estimating the Kinetic Reaction Rate of the Gold Cyanidation Leaching Process

ACS Omega ◽  
2019 ◽  
Vol 4 (22) ◽  
pp. 19880-19894
Author(s):  
Jun Zhang ◽  
Yuanyuan Tan ◽  
Shujiang Li ◽  
Yanhong Wang ◽  
Runda Jia
Keyword(s):  
Reaction Rate ◽  
Alternative Strategies ◽  
Kinetic Reaction ◽  
Leaching Process ◽  
Kinetic Reaction Rate

Label-Free Photonic Crystal Biosensor Integrated Microfluidic Chip for Determination of Kinetic Reaction Rate Constants

2009 ◽  
Vol 9 (12) ◽  
pp. 1697-1704 ◽  
Author(s):  
Charles J. Choi ◽  
Ian D. Block ◽  
Brian Bole ◽  
David Dralle ◽  
Brian T. Cunningham
Keyword(s):  
Photonic Crystal ◽  
Microfluidic Chip ◽  
Rate Constants ◽  
Reaction Rate ◽  
Label Free ◽  
Kinetic Reaction ◽  
Reaction Rate Constants ◽  
Kinetic Reaction Rate

scholarly journals Pemisahan Cerium dari Logam Tanah Jarang Hidroksida Melalui Kalsinasi dan Pelindian Menggunakan HNO3 Encer

EKSPLORIUM ◽  
2019 ◽  
Vol 40 (1) ◽  
pp. 63
Author(s):  
Kurnia Trinopiawan ◽  
Maria Veronica Purwani ◽  
Mutia Anggraini ◽  
Riesna Prassanti
Keyword(s):  
Rare Earth ◽  
Chemical Reaction ◽  
Calcination Time ◽  
Kinetic Reaction ◽  
Calcination Process ◽  
Leaching Process ◽  
Leaching Methods ◽  
Rare Earth Mineral ◽  
Processing Techniques ◽  
Leaching Efficiency

ABSTRAKAplikasi Logam Tanah Jarang (LTJ) banyak digunakan di berbagai bidang yang berhubungan dengan modernisasi. Hal ini menyebabkan banyak perusahaan mengembangkan teknik pengolahan untuk mengekstraksi LTJ dari deposit mineral tanah jarang. Pengolahan LTJ hidroksida menjadi cerium oksida, lanthanum oksida dan konsentrat neodimium telah dilakukan oleh PSTA-BATAN bekerjasama dengan PTBGN-BATAN. Setelah dilakukan kajian keekonomian, ternyata penggunaan asam nitrat pekat pada proses pelarutan cerium meyebabkan pemakaian ammonia berlebih. Oleh karena itu, inovasi proses perlu dilakukan menggunakan metode kalsinasi dan pelindian hasil kalsinasi dengan HNO3 encer. Penelitian ini bertujuan untuk mengetahui efektifitas proses kalsinasi dan pelindian dengan HNO3 encer. Kalsinasi pada suhu 1000°C dengan parameter yang diamati adalah waktu kalsinasi, konsentrasi HNO3, dan tingkat pelindian. Dari hasil penelitian diketahui bahwa kalsinasi dapat mengkonversi LTJ hidroksida menjadi LTJ oksida. Semakin lama waktu kalsinasi, LTJ oksida yang terbentuk semakin sempurna. Proses kalsinasi selama tiga jam meningkatkan kadar La, Ce, dan Nd yang semula 7,80%; 28,00%; dan 15,11% menjadi 12,69%; 45,50%; dan 24,45%. Kinetika reaksi kalsinasi LTJ hidroksida mengikuti proses reaksi kimia dengan persamaan y = 0,3145x + 0,0789 dan R2 = 0,9497. Kemudian, LTJ oksida hasil kalsinasi direaksikan dengan HNO3 encer. Semakin besar konsentrasi HNO3 pada berbagai tingkat pelindian, efisiensi pelindian La dan Nd semakin besar sedangkan Ce tidak dapat dilakukan pelindian atau efisiensi pelindian mendekati nol. Proses pelindian optimum pada kondisi pelindian tiga tingkat menggunakan 1 M HNO3. Kinetika reaksi pelindian mengikuti model susut inti reaksi kimia permukaan dengan persamaan y = 0,1732x – 0,2088 dan R2 = 0,9828.ABSTRACTApplication of Rare Earth Elements (REE) uses broadly in various fields related to modernization. It causes many companies are developing processing techniques to extract REE from rare earth mineral deposits. REE hydroxide processing into cerium oxide, lanthanum oxide, and neodymium concentrates has conducted by PSTA-BATAN in collaboration with PTBGN-BATAN. The previous economic study issued in excessive ammonia caused by the use of concentrated nitric acid in the cerium dissolution process. Therefore, process innovation is necessary to do by calcination and leaching methods using dilute HNO3. This research aims to determine the effectiveness of the calcination and leaching process with dilute HNO3. Calcination conducted at 1000°C temperatures with the observing parameters is calcination time, HNO3 concentration, and leaching rate. The result of the study is that calcination can convert REE hydroxide into REE oxide. The longer calcination time, the easier the REE oxide formed. The three hours calcination process enhances the concentration of La, Ce, and Nd from 7.80%, 28.00%, and 15.11% to 12.69%, 45.50%, and 24.45% respectively. The kinetic reaction of the RE(OH)3 calcination reaction follows a chemical reaction process with the equation y = 0.3145x + 0.0789 and R2 = 0.9497. Then, REE oxide from calcination reacted with dilute HNO3. The higher the concentration of HNO3 at various leaching levels, the better the leaching efficiency of La and Nd while Ce is impossible to leach or the leaching efficiency is close to zero. The optimum leaching process on three levels of leaching conditions is using 1 M HNO3. The leach reaction kinetics follows the core shrinkage model of the surface chemical reaction with the equation y = 0.1732x - 0.2088 and R2 = 0.9828.

scholarly journals Synthesis and Photocatalytic Activity of Polyhedral BiVO4

2020 ◽  
Vol 1 (4) ◽  
pp. 12
Author(s):  
Jianfei Chen ◽  
Ranbo Yu ◽  
Zumin Wang
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Reaction Rate ◽  
Photocatalytic Performance ◽  
Absorption Capacity ◽  
Step Method ◽  
Kinetic Reaction ◽  
Visible Light Absorption ◽  
Pure Phase

<p>Polyhedral BiVO<sub>4</sub> was prepared by hydrothermal-calcination two-step method. The physicochemical properties of polyhedral BiVO<sub>4</sub> were characterized by XRD, TG/DTA, SEM and UV-vis DRS. The photocatalytic properties of the samples were investigated by using 10 mg/L methylene blue (MB) as the target degradant. The experimental results showed that the  prepared polyhedral BiVO<sub>4</sub> is monoclinic. The morphology is about 10 μm polyhedral block. The pure phase BiVO<sub>4</sub> has strong visible light absorption capacity. Under visible light irradiation, the prepared BiVO<sub>4</sub> can degrade 90% of MB within 40 min. Moreover, the photocatalytic performance was further improved by forming a BiVO4/BiOCl heterojunction, and the kinetic reaction rate was 1.5 times that of the pure phase BiVO<sub>4</sub></p>

scholarly journals Optimization of Nano- Photocatalytic Reactor for Organophosphorus Degradation

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Ilin Sadeghi ◽  
Pooya Arbab ◽  
Mahdi Fathizadeh ◽  
Hoseen Fakhraee ◽  
Mahdi Amrollahi
Keyword(s):  
Reaction Rate ◽  
Ph Value ◽  
Lag Time ◽  
Complete Oxidation ◽  
Triethyl Phosphate ◽  
Kinetic Reaction ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Kinetic Order ◽  
Complete Degradation

The photocatalytic decontamination of triethyl phosphate (TEP) is studied by the UV/nano-TiO2process. The nano-TiO2concentration and pH value for the complete oxidation of TEP were investigated in different concentrations of TEP. The kinetic reaction was calculated for TEP as a function of initial concentration of TEP. Results of adsorptions showed that TEP was adsorbed better in alkalinity pH, and the natural pH had the highest reaction rate for complete degradation. Also, the zero-kinetic order with the lag time as a function of initial concentration of TEP and TiO2was suggested for oxidation of TEP. The optimized concentration of nano-TiO2was 400 mg/lit which had the best conversion and the lowest lag time in the reaction.

scholarly journals Simplified Rate Expression for Palm Kernel Oil (PKO) and Methanol Alkali Catalyzed Transesterification Reaction

2020 ◽  
Vol 5 (5) ◽  
pp. 599-606
Author(s):  
A. D. Okewale ◽  
Millionaire Freeborn Nestor Abowei ◽  
F. O. Agbogun ◽  
C. N. Owabor
Keyword(s):  
Reaction Rate ◽  
Palm Kernel ◽  
Physicochemical Characterization ◽  
Reaction Rates ◽  
Transesterification Reaction ◽  
Biodiesel Production ◽  
Kinetic Reaction ◽  
Palm Kernel Oil ◽  
Kernel Oil ◽  
Rate Expression

The need for the development of simplified kinetics rates expression (-RA) for Vegetable Oils Alkali catalyzed Transesterification processes to enhance biodiesel production motivated this study. The study, therefore aimed at proposing unified simple rate expression that may be a useful prelude to design various reactor types for Alkali Catalyzed Transesterification of palm kernel oil (PKO) and Methanol reactions. The kinetics   rate expression is proposed using simple explicit algebraic technique with the consideration that alkali catalyzed transesterification reaction of palm kernel oil and methanol is a reversible bimolecular reaction. The proposed kinetic reaction rate expression is developed as a function of conversion (XA), reactants and products concentration and reaction rate constants (k1 and k2). The kinetics reaction rate expression obtained is further evaluated   on the basis of reactants and product molar masses and densities. The developed models were simulated using Matlab codes programming techniques. The results for kinetic reaction rates (-RA & -ReA) decreases with decrease in fractional volume change (e) and increase in fractional conversion at constant reaction time. The results were quite compatible with those of inferential laboratory physicochemical characterization reported.

scholarly journals STUDI OZONISASI SENYAWA ORGANIK AIR LINDI TEMPAT PEMROSESAN AKHIR SARIMUKTI

Teknik ◽  
2013 ◽  
Vol 34 (2) ◽  
pp. 82
Author(s):  
Arya Rezagama
Keyword(s):  
Reaction Rate ◽  
Batch Reactor ◽  
Reaction Rate Constant ◽  
Hydroxyl Groups ◽  
Kinetic Reaction ◽  
Average Percentage ◽  
Best Value ◽  
Electrophilic Addition Reaction ◽  
System Use ◽  
Air Discharge

Existing treatment leachate from Sarimukti Landfill doesn’t meet the quality standards of waste water.Preliminary treatment is necessary to break down persistent leachate compounds. Ozone can act directly orindirectly with organic material (Glaze 1986). Column batch reactor system use one liter volume. Ozone ispumped into the leachate in the form of fine bubbles. Variations include Ozone Pumping Flow, Ratio ofhigh/diameter (t/d), and pH. Kinetic Reaction of oxygen dissolution in the average leachate is zero order.Increased pumping air discharge and increased pH makes ozone transfer process better. Best value occurs at pH11, where the value of the reaction rate constant ozone 1.48. The average percentage of organic materialallowance 31% COD and 26% TOC. The decline TOC and COD have a tendency to be influenced by the pHoptimum 8-9. At alkaline pH makes carbonate (CO3) formed the greater, that make ozone compounds killquickly. FTIR results showed the intensity of hydroxyl groups increased after ozone oxidation where thesubstitution of functional groups of organic matter associated with electrophilic addition reaction of oxygenatoms. Existence Fulfic acid also increased the effect compounds and Humic Acid, Humad large has been cut byradicals.

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