Improvement in hydration resistance of CaO granules by addition of Zr(OH)4 and Al(OH)3

2018 ◽  
Vol 102 (3) ◽  
pp. 1414-1424 ◽  
Author(s):  
Yaowu Wei ◽  
Tao Zhang ◽  
Qi Zhang ◽  
Bingqiang Han ◽  
Nan Li
Keyword(s):  
Hydration Resistance

scholarly journals New Deposit of Mordenite–Clinoptilolite in the Eastern Region of Cuba: Uses as Pozzolans

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4676
Author(s):  
Jorge Luis Costafreda ◽  
Domingo Alfonso Martín
Keyword(s):  
Effective Properties ◽  
Volcanic Glass ◽  
Heat Of Hydration ◽  
Quality Analysis ◽  
Insoluble Residue ◽  
Eastern Region ◽  
Secondary Phases ◽  
X Ray ◽  
Industrial Manufacturing ◽  
Hydration Resistance

This work describes the newly discovered zeolites in the eastern region of Cuba. In the researched area, there have been no previous studies of natural zeolite exploration. Therefore, the results shown here are new. The main object of this research is to analyse five samples of zeolites and demonstrate their pozzolanic capacity and the possibility of their usage in the industrial manufacturing of pozzolanic cements. The study of the samples was performed by X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM). A chemical analysis (CAQ) to determine the quality of the samples as pozzolans was performed, by determining the total SiO2, reactive SiO2, total CaO, reactive CaO, Al2O3, MgO and the insoluble residue (I.R.). Lastly, an eight-day pozzolanicity analysis (PA) was carried out to determine the pozzolanic reactivity of the samples. The results obtained by XRD, XRF and SEM established that the researched zeolite samples have two main zeolitic phases: mordenite and clinoptilolite. Altered volcanic glass, quartz and smectite (montmorillonite) are the secondary phases. The results of the chemical quality analysis (CAQ) showed that the samples contain a considerable amount of reactive SiO2 and reactive CaO, as well as a low content of insoluble residue, which reinforces their properties as pozzolans. The results of the pozzolanicity analysis (PA) concluded that the analysed samples actively react with Ca(OH)2 after eight days. Based on all the results mentioned above, it is established that both mordenite and clinoptilolite behave like pozzolans and can be recommended for the manufacture of pozzolanic cements, which have more effective properties than Portland cement, in terms of physical, chemical and mechanical strength, low heat of hydration, resistance to sulphates, low CO2 emissions to the atmosphere and negligible impacts on the environment.

Core-shell structured CaO aggregate prepared by granulating with Al chelating compound and its hydration resistance

2020 ◽  
Vol 46 (8) ◽  
pp. 10788-10796
Author(s):  
Jinhu Wang ◽  
Yaowu Wei ◽  
Bingrong Li ◽  
Mengrui Li ◽  
Nan Li
Keyword(s):  
Core Shell ◽  
Hydration Resistance

scholarly journals Electrochemistry Study of Permselectivity and Interfacial Electron Transfers of a Branch-Tailed Fluorosurfactant Self-Assembled Monolayer on Gold

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2998 ◽  
Author(s):  
Shanshan Li ◽  
Qingying Luo ◽  
Zhiqing Zhang ◽  
Guanghui Shen ◽  
Hejun Wu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Electrochemical Impedance ◽  
Click Reaction ◽  
Hydration Shell ◽  
Self Assembled Monolayer ◽  
Tunneling Mechanism ◽  
Assembly Technique ◽  
Hydration Resistance ◽  
Self Assembled ◽  
Electron Transfers

We investigated the permselectivity and interfacial electron transfers of an amphiphilic branch-tailed fluorosurfactant self-assembled monolayer (FS-SAM) on a gold electrode by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The FS-SAM was prepared by a self-assembly technique and a “click” reaction. The barrier property and interfacial electron transfers of the FS-SAM were also evaluated using various probes with different features. The FS-SAM allowed a higher degree of permeation by small hydrophilic (Cl− and F−) electrolyte ions than large hydrophobic (ClO4− and PF6−) ones. Meanwhile, the redox reaction of the Fe(CN)63− couple was nearly completely blocked by the FS-SAM, whereas the electron transfer of Ru(NH3)63+ was easier than that of Fe(CN)63−, which may be due to the underlying tunneling mechanism. For hydrophobic dopamine, the hydrophobic bonding between the FS-SAM exterior fluoroalkyl moieties and the hydrophobic probes, as well as the hydration resistance from the interior hydration shell around the oligo (ethylene glycol) moieties, hindered the transport of hydrophobic probes into the FS-SAM. These results may have profound implications for understanding the permselectivity and electron transfers of amphiphilic surfaces consisting of molecules containing aromatic groups and branch-tailed fluorosurfactants in their structures.

Improved hydration resistance of magnesia by EDTA and ammonium phosphate as additives

2017 ◽  
Vol 24 (1) ◽  
pp. 29-33
Author(s):  
Wenzheng Zhang ◽  
Bin Chen ◽  
Jiangnan Mou ◽  
Danyang Wang
Keyword(s):  
Ionic Conductivity ◽  
Ethylene Diamine Tetraacetic Acid ◽  
Volume Expansion ◽  
Particle Distribution ◽  
Ammonium Phosphate ◽  
Ethylene Diamine ◽  
Tetraacetic Acid ◽  
Volumetric Expansion ◽  
Key Factor ◽  
Hydration Resistance

AbstractThe control of magnesia (MgO) hydration ratio is a key factor in refractory slurry processing. The volumetric expansion that follows this reaction can result in MgO product cracks as MgO greatly tends to react with water. Thus, the antihydration of MgO is a key concern in refractory suspension processing. The performances of ammonium phosphate (AP) and ethylene diamine tetraacetic acid (EDTA) as antihydration additives were evaluated by using hydration tests, and ionic conductivity, pH, and particle distribution of MgO powders in water and ethanol were used to provide information related to the MgO powder in different liquids. The results showed that the antihydration additives AP and EDTA can inhibit MgO hydration to some extent; however, AP was more effective in preventing volume expansion.

Effect of MgO Coating on the Hydration Resistance of MgO-CaO Clinkers

2011 ◽  
Vol 695 ◽  
pp. 324-327 ◽  
Author(s):  
Hong Feng Yin ◽  
Yan Long Ma ◽  
Jun Yang
Keyword(s):  
Carbon Source ◽  
Carbon Black ◽  
Reaction Temperature ◽  
Carbothermal Reduction ◽  
Processing Parameters ◽  
Holding Time ◽  
Deposition Mechanism ◽  
The Poor ◽  
Hydration Resistance ◽  
Prolonged Holding

To overcome the disadvantage of MgO-CaO refractories, as the poor hydration resistance, MgO coating on the MgO-CaO clinker was fabricated by carbothermal reduction MgO with carbon as reduction agent and then the oxidation of Mg vapor. Effect of processing parameters (such as carbon source, reaction temperature and holding time) on the hydration resistance of MgO-CaO clinkers were investigated by hydration resistance test and SEM. The results indicated that the hydration resistance of treated MgO-CaO clinkers was improved when carbon black was used as reduction agent due to easy reaction with MgO than the graphite and coke. The high reaction temperature among 1450~1600°C and prolonged holding time within 4 h resulted in improvement of the hydration resistance of treated MgO-CaO clinker. Deposition mechanism of MgO coating on the MgO-CaO clinker was discussed.

Effect of CaO Content and Microstructure on Hydration Resistance of MgO-CaO Clinkers

2007 ◽  
pp. 1679-1682
Author(s):  
Hua Zhi Gu ◽  
Hou Zhi Wang ◽  
Yan Ruo Hong ◽  
Jia Lin Sun ◽  
Wen Jie Zhang
Keyword(s):  
Hydration Resistance
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