scholarly journals The Interaction of Water Suspension Incarbonic Dolomite with Sulfuric Acid and Carbon Dioxide

2016 ◽  
Vol 17 (1) ◽  
pp. 76-80
Author(s):  
O.M. Duda ◽  
I.J. Kostiv
Keyword(s):  
Carbon Dioxide ◽  
Magnesium Oxide ◽  
Calcium Oxide ◽  
Aqueous Suspension ◽  
Inert Material ◽  
Calcium Compound ◽  
Different Temperatures ◽  
Active Calcium ◽  
Soluble Calcium ◽  
Active Magnesium Oxide

The interaction of aqueous suspension of calcium chloride has been studied at different temperatures and at the duration of natural dolomite and solutions of sulfate acid and also carbon dioxide. Studied composition of formed products. Established that the reaction rate of magnesium oxide with acid or carbon dioxide is lower than calcium oxide. The conditions of obtaining of active magnesium with content ballast calcium carbonate and sulfate, which is connected to soluble calcium. For 1023 K temperature forms the most active magnesium oxide, increasing it to 1123 K, magnesium oxide is passivated and increasing the number of active calcium oxide. Soluble calcium compound completely pass into insoluble sulfates or carbonates by passing through a suspension of carbon dioxide or solution of sulfate acid neutralization. Thermo activated dolomite which containing active magnesium oxide and various forms of inert material can be used for obtaining magnesia binders.

Mechanochemically Activated, Calcium Oxide-Based, Magnesium Oxide-Stabilized Carbon Dioxide Sorbents

ChemSusChem ◽  
2016 ◽  
Vol 9 (17) ◽  
pp. 2380-2390 ◽  
Author(s):  
Alexey Kurlov ◽  
Marcin Broda ◽  
Davood Hosseini ◽  
Sharon J. Mitchell ◽  
Javier Pérez-Ramírez ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Magnesium Oxide ◽  
Calcium Oxide

Assessing the reactivity of magnesium oxide calcinated at different temperatures for understanding its role in degradation processes

2020 ◽  
Author(s):  
Tobias Bader ◽  
Anja Diekamp
Keyword(s):  
Magnesium Oxide ◽  
Calcium Oxide ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Development Fund ◽  
Degradation Processes ◽  
European Regional Development Fund ◽  
Different Temperatures ◽  
Historic Mortars ◽  
Dolomite Rock

<p>In Tyrol, Austria, dolomite rock was commonly used as raw material for historic mortars and plasters. During calcination of dolomite rock, almost equal amounts of calcium oxide and magnesium oxide are produced. While the reactivity of calcium oxide is well known, the reactivity of magnesium oxide is still not completely understood. Within this study, the reactivity of magnesium oxide obtained from calcination at different temperatures (600 - 1000 °C) will be examined. For this purpose, natural magnesite (Hochfilzen, Tyrol) will be used instead of natural dolomite rock in order to minimise the influence of calcium oxide on the wet slaking curves. Both, calcination and slaking of magnesite will be studied with the help of X-ray diffraction analysis and thermogravimetric analysis. The gained knowledge is believed to be beneficial for improving the understanding of degradation processes. The study was performed within the Interreg V-A Italy-Austria project named DOLOMIA (ITAT 2036) with the funding by INTERact and the European Regional Development Fund (ERDF) being grateful acknowledged.</p>

scholarly journals Micro-Change Process of Calcium–Magnesium Double Expansive Agent and Its Performance Characterization in Cement-Based Materials

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3269
Author(s):  
Yihang Ding ◽  
Zhongyang Mao ◽  
Yu Wang ◽  
Min Deng ◽  
Mingshu Tang
Keyword(s):  
Compressive Strength ◽  
Magnesium Oxide ◽  
Calcium Oxide ◽  
Cement Paste ◽  
Change Process ◽  
Development Trend ◽  
Different Temperatures ◽  
Calcium Magnesium ◽  
Microscopic Change ◽  
Microscopic Morphology

With the increase of cement output, the demand for cement expansion agents increases, and composite expansion agents have become the development trend. The purpose of this study is to study the microscopic change process and expansion effect of calcium oxide and magnesium oxide double expansion agents. After calcination at different temperatures, the change process of microscopic morphology of calcined products was observed. Through calcining dolomite at 900 °C, the mixture D900 of calcium oxide and magnesium oxide was obtained. To prepare mixed cement, 10 wt %, 20 wt %, and 30 wt % of D900 were added into cement to prepare mixed cement. At the same time, the compressive strength, deformation, and porosity of mixed cement were measured. The results show that adding D900 improves the expansion rate of early cement paste and reduces the compressive strength. After 120 days, the compressive strength of 20 wt % cement paste is higher than that of blank cement paste, and the porosity of 20 wt % cement paste is the lowest among the three mixed cements. This shows that 20 wt % is a more suitable substitute.

scholarly journals The Effect of the Temperature and Moisture to the Permeation Properties of PEO-Based Membranes for Carbon-Dioxide Separation

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2053
Author(s):  
Dragutin Nedeljkovic
Keyword(s):  
Carbon Dioxide ◽  
Partial Pressure ◽  
Carbon Dioxide Emission ◽  
Combustion Products ◽  
Mixed Matrix Membranes ◽  
Mixed Matrix Membrane ◽  
Mixed Matrix ◽  
Gas Treatment ◽  
Carbon Dioxide Separation ◽  
Different Temperatures

An increased demand for energy in recent decades has caused an increase in the emissions of combustion products, among which carbon-dioxide is the most harmful. As carbon-dioxide induces negative environmental effects, like global warming and the greenhouse effect, a decrease of the carbon-dioxide emission has emerged as one of the most urgent tasks in engineering. In this work, the possibility for the application of the polymer-based, dense, mixed matrix membranes for flue gas treatment was tested. The task was to test a potential decrease in the permeability and selectivity of a mixed-matrix membrane in the presence of moisture and at elevated temperature. Membranes are based on two different poly(ethylene oxide)-based polymers filled with two different zeolite powders (ITR and IWS). An additive of detergent type was added to improve the contact properties between the zeolite and polymer matrix. The measurements were performed at three different temperatures (30, 60, and 90 °C) under wet conditions, with partial pressure of the water equal to the vapor pressure of the water at the given temperature. The permeability of carbon-dioxide, hydrogen, nitrogen, and oxygen was measured, and the selectivity of the carbon-dioxide versus other gases was determined. Obtained results have shown that an increase of temperature and partial pressure of the vapor slightly increase both the selectivity and permeability of the synthesized membranes. It was also shown that the addition of the zeolite powder increases the permeability of carbon-dioxide while maintaining the selectivity, compared to hydrogen, oxygen, and nitrogen.

scholarly journals Determination of Oleanolic and Ursolic Acids inHedyotis diffusaUsing Hyphenated Ultrasound-Assisted Supercritical Carbon Dioxide Extraction and Chromatography

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Ming-Chi Wei ◽  
Yu-Chiao Yang ◽  
Show-Jen Hong
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
High Performance ◽  
Extraction Yield ◽  
Extraction Time ◽  
Different Temperatures ◽  
Ultrasound Assisted ◽  
High Concentrations ◽  
Static Extraction ◽  
Supercritical Carbon

Oleanolic acid (OA) and ursolic acid (UA) were extracted fromHedyotis diffusausing a hyphenated procedure of ultrasound-assisted and supercritical carbon dioxide (HSC–CO2) extraction at different temperatures, pressures, cosolvent percentages, and SC–CO2flow rates. The results indicated that these parameters significantly affected the extraction yield. The maximal yields of OA (0.917 mg/g of dry plant) and UA (3.540 mg/g of dry plant) were obtained at a dynamic extraction time of 110 min, a static extraction time of 15 min, 28.2 MPa, and 56°C with a 12.5% (v/v) cosolvent (ethanol/water = 82/18, v/v) and SC–CO2flowing at 2.3 mL/min (STP). The extracted yields were then analyzed by high performance liquid chromatography (HPLC) to quantify the OA and UA. The present findings revealed thatH. diffusais a potential source of OA and UA. In addition, using the hyphenated procedure for extraction is a promising and alternative process for recovering OA and UA fromH. diffusaat high concentrations.

Effectiveness of Steam Treating Method on Inhibiting the Expansive Problem of Concrete with Slag as Aggregate

2013 ◽  
Vol 723 ◽  
pp. 609-616
Author(s):  
Wei Chien Wang ◽  
Chih Chien Liu ◽  
Chau Lee
Keyword(s):  
Magnesium Oxide ◽  
Calcium Oxide ◽  
Steel Industry ◽  
Volume Expansion ◽  
Steam Treatment ◽  
Free Calcium ◽  
Concrete Aggregate ◽  
Furnace Slag ◽  
By Products

The furnace slag are the by-products of the steel industry, the main ingredients are the oxide of calcium, alumina and magnesium, and some silica. Slag used as concrete aggregate could cause the problem of the volume expansion of concrete. The expansion problem may be produced by ASR or free calcium oxide and magnesium oxide in slag. This research stabilizing the non-ASR reactive slag using steam treatment analyzes the effectiveness of steam treating technique inhibiting the expansive problem for slag used in concrete. And this paper also discusses the effect of the steam treating time on the performance of inhibiting the expansive problem.

scholarly journals Quality and shelf life of packaged fresh sliced mushrooms stored at two different temperatures

2008 ◽  
Vol 15 (4) ◽  
pp. 414 ◽  
Author(s):  
E. GONZÁLEZ-FANDOS ◽  
A. SIMON JIMENES ◽  
V. TOBAR PARDO
Keyword(s):  
Carbon Dioxide ◽  
Shelf Life ◽  
Agaricus Bisporus ◽  
Microbiological Quality ◽  
Air Atmosphere ◽  
Pvc Film ◽  
Different Temperatures ◽  
Aerobic And Anaerobic ◽  
Quality And Shelf Life

The sensory and microbiological quality of sliced mushrooms (Agaricus bisporus L.) packaged in films of perforated and non-perforated PVC and stored at 3 and 9ºC, was studied. The carbon dioxide and oxygen content inside the packages, colour, weight loss, sensory attributes, mesophiles, Pseudomonas, Enterobacteriaceae, aerobic and anaerobic spore formers were determined. The atmosphere generated with the perforated PVC film was similar to that of air atmosphere at 3 or 9ºC. T.he non-perforated PVC film generated inside the packages CO2 : O2 concentrations of 3.4% : 8.1% at 3ºC and CO2 : O2 concentrations of 4.5% : 0.15% at 9ºC. Browning of mushrooms was lower at 3 than at 9ºC. The quality of sliced mushrooms packaged in perforated PVC and stored at 3ºC was adequate after 9 days. However, at 9ºC, the slice deformation and brown blotches incidence were severe after 9 days. The atmosphere generated with non-perforated PVC inhibited aerobic microorganism growth compared to mushrooms packaged in perforated PVC. At 3ºC, the shelf life of mushrooms packaged in non perforated PVC was around 13 days. However, the extremely low O2 atmospheres generated at 9ºC was accompanied by off-odours and growth of anaerobic spore formers, although the appearance of sliced mushrooms was acceptable.;

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