Study of Thermal Reduction of Barium Sulphate for Barium Sulphide Preparation

2017 ◽  
Author(s):  
Magdalena Balintova ◽  
Stefan Demcak ◽  
Adriana Estokova ◽  
Marian Holub ◽  
Petra Pavlikova
Keyword(s):  
Thermal Analysis ◽  
Colorimetric Method ◽  
Barium Sulphate ◽  
Thermal Reduction ◽  
Infrared Spectrometry ◽  
Acidic Solutions ◽  
Biological Removal ◽  
Barium Compounds ◽  
Insoluble Product ◽  
Sulphate Removal

Industrial wastewaters, particularly those associated with mining and mineral processing, can contain high con-centrations of sulphate. There are various methods of sulphate removal e.g. reverse osmosis, ion exchange, precipitation by lime, cements, and salts of barium and the biological removal process. The soluble salts of barium are most commonly used for precipitation of sulphate from aquatic acidic solutions to the insoluble product barium sulphate BaSO4. Benefits of precip-itation are high sulphate removal efficiency but limitations are toxicity of barium compounds and high economical costs. For this reason the recycling of BaSO4 to barium sulphide BaS (the precipitating reagent) is very important. The paper deals with study of BaSO4 reduction by activated carbon to BaS by thermal analysis and infrared spectrometry. DCS analysis indicated that conversion of BaSO4 to BaS in the range of temperature 800–1,000 °C was performed. Thermal analysis and infrared spectra of the products confirmed the change in its composition, but process of reduction by carbon was incomplete and in sample was still present a part of BaSO4. Presence of BaS was confirmed by colorimetric method.

Fabrication and In-Situ Thermal Reduction of Gold Nanofibers

2020 ◽  
Vol 12 (8) ◽  
pp. 1109-1115
Author(s):  
Xiaojiao Yang ◽  
Jun Li ◽  
Ying Liu
Keyword(s):  
Thermal Analysis ◽  
Gold Nanoparticles ◽  
Fourier Transform ◽  
Average Diameter ◽  
Thermal Reduction ◽  
Gold Content ◽  
Gold Salt ◽  
One Dimensional ◽  
Nanoelectronic Devices

One-dimensional gold nanofibers are good candidates for next generation nanoelectronic devices. Here, gold nanofibers were synthesized via electrospinning with subsequent in-situ thermal reduction. The thermal behavior of the precursor nanofibers was investigated by thermogravimetric/differential thermal analysis and fourier transform infrared. The polymer parts are decomposed and removed step by step, meanwhile, gold salt is decomposed and in-situ reduced to form gold nanoparticles in air without any reducing agent or gas due to its strong oxidation ability. The effects of gold content, polymers type (PVP, PVA, PAN), calcination atmospheres (Air, H2, H2/Ar) and temperatures (200 °C to 500 °C) on the morphology and structures of gold nanofibers were characterized by XRD, SEM, and TEM. The results shows that PVP is the optimal polymer with the gold content of 6:1 (PVP:Au) to fabricate the continuous gold nanofibers with good morphology and structures. The final gold nanofibers with average diameter of 60 nm and several hundred micrometers long, were fabricated after calcined at 500 °C in air for 2 hours. It was composed of gold nanoparticles that ranged from 5 to 30 nm.

scholarly journals ELECTRON MICROSCOPIC AND KINETIC STUDIES DEALING WITH AN ARTIFICIAL ENZYME MEMBRANE APPLICATION TO A CYTOCHEMICAL MODEL WITH THE HORSERADISH PEROXIDASE-3,3'-DIAMINOBENZIDINE SYSTEM

1974 ◽  
Vol 22 (11) ◽  
pp. 1048-1059 ◽  
Author(s):  
J. N. BARBOTIN ◽  
D. THOMAS
Keyword(s):  
Horseradish Peroxidase ◽  
Colorimetric Method ◽  
Kinetic Studies ◽  
Artificial Enzyme ◽  
Product Concentration ◽  
Electron Microscopic ◽  
First Order ◽  
Diffusion Limitations ◽  
Insoluble Polymer ◽  
Insoluble Product

A new colorimetric method for measuring horseradish peroxidase (HRP) activity, in solution, with 3,3'-diaminobenzidine (DAB) as the hydrogen donor is presented. The same method was also used to test HRP activity when immobilized in an artificial proteic membrane. The reaction was shown to be of first order in both cases. Direct spectrophotometric measurements dealing with HRP membrane show that the total amount of insoluble polymer produced does not increase linearly with the quantity of enzyme introduced in the membrane. Moreover, a study of the DAB permeability through membranes with or without peroxidase activity was performed to allow the study of diffusion limitations. Membranes have also been studied by electron microscopy. We have especially visualized the existence of product concentration profiles inside the membrane. The results show that in the membrane there is no geometrical similarity between the distribution profiles of the enzyme and of the insoluble product.

The Influence of Barium Compounds on the Formation of Portland Cement Clinker

2016 ◽  
Vol 851 ◽  
pp. 116-121
Author(s):  
Anežka Zezulová ◽  
Theodor Staněk ◽  
Tomáš Opravil
Keyword(s):  
Portland Cement ◽  
Large Scale ◽  
Barium Carbonate ◽  
Barium Oxide ◽  
Rietveld Analysis ◽  
Barium Sulphate ◽  
Cement Clinker ◽  
Scale Production ◽  
Barium Ions ◽  
Barium Compounds

Portland clinker is thanks to its large-scale production a continuously studied topic. Clinker, or Portland cement, is used for construction purposes or for insulation and special applications. One of these special applications could be shielding of different types of radiation by making use of the content of barium ions. The present article examines the influence of barium oxide on the formation and properties of Portland clinker, which could be, by incorporation of barium ions into the system, used as a binder for buildings resistant to various types of radiation. Barium sulphate and barium carbonate were added to the raw meal in order to prepare clinkers with different content of barium oxide. The effect of barium on the formation of clinker phases was studied (by XRD – Rietveld analysis and by the microscopic point counting method), as well as the rate of alite formation under isothermal conditions. Furthermore, the ability of barium to become a part of clinker minerals was studied by SEM with EDS.

Sulphate Removal for Barium Sulphate Mitigation - Kinetic vs.

2005 ◽  
Author(s):  
Caroline Simpson ◽  
Gordon M. Graham ◽  
Ian Ralph Collins ◽  
John E. McElhiney ◽  
Roy A. Davis
Keyword(s):  
Barium Sulphate ◽  
Sulphate Removal

Biological Removal of Sulphate from Industrial Effluents and Concomitant Production of Sulphur

1989 ◽  
Vol 21 (4-5) ◽  
pp. 265-276 ◽  
Author(s):  
J. P. Maree ◽  
E. Hill
Keyword(s):  
Heavy Metals ◽  
Calcium Carbonate ◽  
Industrial Effluents ◽  
Elemental Sulphur ◽  
Biological Removal ◽  
Pollution Problem ◽  
Environmental Pollution Problem ◽  
Waste Gypsum ◽  
Sulphate Removal ◽  
By Products

Sulphate wastes, such as sulphate-rich industrial effluents or waste gypsum, present a serious environmental pollution problem. A biological sulphate removal process has been evaluated for the treatment of these wastes. In this process, sulphate is converted to H2S when a carbon source, such as molasses is added. A complete mix reactor was used for sulphate reduction to H2S, which was subsequently stripped off in a closed system with either CO2 or nitrogen as carrier gas. The H2S in turn is oxidized to elemental sulphur in the sulphur production stage when it is brought into contact with a ferric solution. In a subsequent aerobic stage, degradation of organic carbon residuals and calcium carbonate crystallization are achieved simultaneously. Strontium, which is present in waste gypsum, is removed partially in the anaerobic stage, and completely in the aerobic stage. It is shown that sulphate wastes can be treated by the biological sulphate process for the production of reusable water and/or the recovery of valuable by-products such as elemental sulphur, sodium bisulphide and heavy metals.

scholarly journals Chemical Property Changes and Thermal Analysis during the Carbonizing Process of the Pollen Grains of Typha

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 128 ◽  
Author(s):  
Mingliang Gao ◽  
Beihua Bao ◽  
Yudan Cao ◽  
Mingqiu Shan ◽  
Fangfang Cheng ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Process Condition ◽  
Pollen Grains ◽  
Color Measurement ◽  
Infrared Spectrometry ◽  
Heating Process ◽  
Monitoring Methods ◽  
Processing Theory ◽  
Optimal Processing ◽  
Property Changes

Carbonized pollen grains of Typha (CPT) were widely used in clinical for antithrombosis, wound and bleeding in China. In order to ensure the role of drugs, it is very important to control the quality of drugs. However, there is a lack of monitoring methods in the process of charcoal preparation. To characterize the process of CPT, we used thermal analysis, scanning electron microscope (SEM), color measurement, Fourier transform infrared spectrometry (FTIR) and HPLC. In this study, 7 min was the optimal processing time and the heating process condition should be controlled under 272.35 ± 7.23 °C. This comprehensive strategy to depict the whole carbonizing process would provide new ideas for researches on quality control of Traditional Chinese Medicine (TCM) and processing theory of charcoal medicine.

Thermal Analysis on Vacuum Synchronous Reduction for the Preparation of Mg-Sr Alloy

2009 ◽  
Vol 610-613 ◽  
pp. 979-983 ◽  
Author(s):  
Lei Li ◽  
Xiao Dong Peng ◽  
Dong Ya Wang ◽  
Wei Dong Xie ◽  
Shou Cheng Wang ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Phase Composition ◽  
Reduction Method ◽  
Reduction Process ◽  
Thermal Reduction ◽  
Essential Condition

Mg-Sr alloy was prepared by the vacuum synchronous reduction method at a temperature of 1100°C. The phase composition of the reaction product and slag was analyzed by XRD. Results showed that Mg17Sr2 and α-Mg were formed in the product while Ca2SiO4 and Sr2SiO4 existed in the slag. DSC-TG curves obtained from thermal analysis of the reduction process indicated that vacuum was an essential condition in the preparation of Mg-Sr alloy by synchronous thermal reduction method when temperature was below 1200°C.

Phase composition analysis of hydrous aluminium oxides by thermal analysis and infrared spectrometry

Talanta ◽  
1992 ◽  
Vol 39 (12) ◽  
pp. 1583-1586 ◽  
Author(s):  
Zs. Wittmann ◽  
E. Kántor ◽  
K. Bélafi ◽  
L. Péterfy ◽  
L.P. Farkas
Keyword(s):  
Thermal Analysis ◽  
Phase Composition ◽  
Infrared Spectrometry ◽  
Composition Analysis ◽  
Phase Composition Analysis
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