Empirical Model to Estimate Mn2+ Precipitation Rate from a Leaching Solution Using SO2/O2 as Oxidizing Agent

2012 ◽  
Vol 1380 ◽  
Author(s):  
S. Bello-Teodoro ◽  
R. Pérez-Garibay
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Reaction Rates ◽  
Precipitation Process ◽  
Low Grade ◽  
Gas Flow Rate ◽  
Oxidative Precipitation ◽  
Leaching Solution ◽  
Good Concordance ◽  
Main Influence

ABSTRACTA method, based in leaching with SO2, to process low grade pyrolusite minerals has shown good results at laboratory scale. After the separation of the solid impurities, the dissolved manganese is subsequently precipitated using the SO2/O2 gas mixture as oxidising agent. In this research it was obtained a mathematical model to estimate the oxidative precipitation process, as a function of temperature, pH and SO2 gas flow rate. It was found that pH and temperature have the main influence in the reaction rate. An optimal SO2 concentration in the mixture must be used to avoid generation of reductive conditions. It was observed a most efficient reaction with a low gas flow rate injection. The predicted reaction rates presents a good concordance with the experimental results (R2=0.97), showing a worthy potential for practical uses.

Theoretical Aspects and Design of a Low-Power, Low-Flow-Rate Torch in Inductively Coupled Plasma Atomic Emission Spectroscopy

1984 ◽  
Vol 38 (5) ◽  
pp. 647-653 ◽  
Author(s):  
G Angleys ◽  
J. M. Mermet
Keyword(s):  
Flow Rate ◽  
Inductively Coupled Plasma ◽  
Gas Flow ◽  
Atomic Emission ◽  
Low Flow ◽  
Gas Flow Rate ◽  
Inductively Coupled ◽  
Torch Design ◽  
Practical Design ◽  
Main Influence

Based on a previously published work, calculations of the minimum plasma gas flow rate for torch tubes of various dimensions have been performed Predicted minimum rates have been verified by experiment It is possible to sustain a discharge at 600 W and 6 L/min without reducing drastically the external size of the torch One of the main parameters in torch design is the various flow velocities The main influence on the plasma gas flow rate is provided by the space between the external and the intermediate tube A practical design is proposed and a comparison is made with the literature

scholarly journals Pengendapan Uranium pada Monasit Bangka sebagai Ammonium Diuranate (ADU) Menggunakan Gas NH3

EKSPLORIUM ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 45
Author(s):  
Riesna Prassanti ◽  
Ahmad Miftah Fauzan ◽  
Aditya Widian Putra ◽  
Afiq Azfar Pratama ◽  
Erlan Dewita ◽  
...  
Keyword(s):  
Flow Rate ◽  
Contact Time ◽  
Gas Flow ◽  
Sulfate Solution ◽  
Precipitation Process ◽  
Processing Temperature ◽  
Radioactive Elements ◽  
Gas Flow Rate ◽  
Energy Agency ◽  
Ammonium Diuranate

ABSTRAK Monasit, sebagai produk ikutan penambangan timah, mengandung unsur-unsur logam tanah jarang (LTJ) serta unsur radioaktif seperti uranium (U) dan torium (Th). Penelitian dan pengembangan pengolahan monasit di Pusat Teknologi Bahan Galian Nuklir-Badan Tenaga Nuklir Nasional (PTBGN-BATAN) telah berhasil memisahkan LTJ sebagai senyawa hidroksida dengan recovery 85%. Unsur radioaktif U dan Th masing-masing diperoleh sebagai produk dalam bentuk konsentrat senyawa ammonium diuranate (ADU)/(NH4)2U2O7 dan torium hidroksida (Th(OH)4). Pada penelitian sebelumnya, pemisahan U sebagai ADU pada monasit dilakukan dengan proses pengendapan menggunakan larutan NH4OH. Pada penelitian, U ini akan diendapkan sebagai ADU menggunakan reagen gas NH3 dengan tujuan memperoleh kondisi optimum pengendapan. Umpan pengendapan berupa larutan (U,Th,LTJ) sulfat diperoleh dari proses pengolahan monasit secara basa yaitu dekomposisi menggunakan NaOH, pelarutan parsial menggunakan HCl, dan pelarutan total menggunakan H2SO4. Parameter yang diteliti meliputi pengaruh laju alir gas NH3, temperatur proses, dan waktu kontak terhadap recovery U. Hasil penelitian menunjukkan bahwa pada kondisi statis pH-7, kondisi optimum pengendapan U menggunakan gas NH3 adalah pada laju alir gas NH3 150 ml/menit, temperatur proses 30oC, dan waktu kontak 15 menit dengan recovery pengendapan U 100%, Th 99,97%, dan LTJ 99,93%. Hasil tersebut menunjukkan bahwa unsur U sudah terambil seluruhnya akan tetapi masih bercampur dengan unsur lain yaitu Th dan LTJ, sehingga diperlukan penelitian berikutnya untuk memperoleh U dengan kemurnian yang tinggi pada kondisi pH optimum.ABSTRACT Monazite, as a by-product of tin mining, contains rare earth elements (REE) and radioactive elements like uranium (U) and thorium (Th). The monazite processing Research and Development at the Center for Nuclear Mineral Technology-National Nuclear Energy Agency (PTBGN-BATAN) has succeeded in separating REE as a hydroxide compound with an 85% recovery. The radioactive elements U and Th are each obtained as a product in the form of concentrated compounds of ammonium diuranate (ADU)/(NH4)2U2O7 and thorium hydroxide (Th(OH)4). In previous studies, the separation of U as ADU in monazite was carried out by the precipitation process using NH4OH solution. In this research, U will be precipitated as an ADU using NH3 gas reagents to obtain precipitation optimum conditions. Precipitation feed in the form of (U, Th, REE) sulfate solution derived from the monazite processing using the alkali or base method, which includes decomposition using NaOH, partial dissolution using HCl, and total dissolution using H2SO4. The parameters studied include the effect of NH3 gas flow rate, process temperature, and contact time on U recovery. The results showed that on the static pH-7 condition, the optimum state of U precipitation using NH3 gas is at NH3 gas flow rate of 150 ml/minutes, processing temperature of 30oC, and 15 minutes contact time with precipitation recovery of U 100%, Th 99.97%, and REE 99.93%. These results indicate that U has been taken entirely but still mixed with other elements, which are Th and REE, so that further research is needed to obtain U with high purity on optimum pH condition.

SCIENTIFIC AND ENGINEERING PRINCIPLES OF EFFICIENT FUEL USE AND ENVIRONMENTALLY FRIENDLY GAS COMBUSTION IN STOVE PLATES. PART 1. MODERN STATE-OF-THE-ART AND DIRECTIONS FOR IMPROVEMENT THE GAS BURNING IN DOMESTIC GAS COOKERS

2017 ◽  
pp. 3-18 ◽  
Author(s):  
B.S. Soroka ◽  
V.V. Horupa
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Gas Flow ◽  
Renewable Energy Sources ◽  
Combustion Process ◽  
Orifice Diameter ◽  
Firing Process ◽  
Gas Flow Rate ◽  
Gas Combustion ◽  
Gas Stoves

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.

On the Influence of Fluctuating Flow Rate Upon the Performance and Behaviour of Isothermal Reacting Systems

1998 ◽  
Vol 63 (6) ◽  
pp. 881-898
Author(s):  
Otakar Trnka ◽  
Miloslav Hartman
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Fluidized Bed Reactor ◽  
Computational Techniques ◽  
Continuous Stirred Tank Reactor ◽  
Gas Flow Rate ◽  
Solid Reaction ◽  
Continuous Stirred Tank ◽  
And Performance ◽  
Reacting Systems

Three simple computational techniques are proposed and employed to demonstrate the effect of fluctuating flow rate of feed on the behaviour and performance of an isothermal, continuous stirred tank reactor (CSTR). A fluidized bed reactor (FBR), in which a non-catalytic gas-solid reaction occurs, is also considered. The influence of amplitude and frequency of gas flow rate fluctuations on reactant concentrations at the exit of the CSTR is shown in four different situations.

scholarly journals Investigation on influences of loose gas on gas-solid flows in a circulating fluidized bed (CFB) reactor using full-loop numerical simulation

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Pengju Huo ◽  
Xiaohong Li ◽  
Yang Liu ◽  
Haiying Qi
Keyword(s):  
Numerical Simulation ◽  
Flow Rate ◽  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Separation Efficiency ◽  
Circulation Rate ◽  
Solid Mass ◽  
Gas Flow Rate ◽  
Gas Leakage ◽  
Mass Circulation

AbstractThe influences of loose gas on gas-solid flows in a large-scale circulating fluidized bed (CFB) gasification reactor were investigated using full-loop numerical simulation. The two-fluid model was coupled with the QC-energy minimization in multi-scale theory (EMMS) gas-solid drag model to simulate the fluidization in the CFB reactor. Effects of the loose gas flow rate, Q, on the solid mass circulation rate and the cyclone separation efficiency were analyzed. The study found different effects depending on Q: First, the particles in the loop seal and the standpipe tended to become more densely packed with decreasing loose gas flow rate, leading to the reduction in the overall circulation rate. The minimum Q that can affect the solid mass circulation rate is about 2.5% of the fluidized gas flow rate. Second, the sealing gas capability of the particles is enhanced as the loose gas flow rate decreases, which reduces the gas leakage into the cyclones and improves their separation efficiency. The best loose gas flow rates are equal to 2.5% of the fluidized gas flow rate at the various supply positions. In addition, the cyclone separation efficiency is correlated with the gas leakage to predict the separation efficiency during industrial operation.

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