scholarly journals An investigation of the chemical composition and acid corrosion of pedra sabão (soapstone)

2005 ◽  
Vol 70 (2) ◽  
pp. 261-268 ◽  
Author(s):  
Farias de
Keyword(s):  
Sulfuric Acid ◽  
Chemical Composition ◽  
Acid Corrosion ◽  
Acid Solutions ◽  
Nmr Analysis ◽  
Acid Attack ◽  
Basic Study ◽  
Oh Groups ◽  
Composition And Structure ◽  
Sulfuric Acid Solutions

In this paper the results of a basic study of the chemical composition and structure of soapstone are reported. An investigation of the effects of aqueous sulfuric acid solutions on the physical integrity of the stone was also performed. The studied soapstone samples had a lamellar nanostructure as verified by DRX data. Furthermore, they contained isolated silanol (Si-OH) groups, as indicated by FTIR data, and the majority of the silicon atoms were bonded to OH groups, as shown by 29Si CPMAS NMR analysis. Is was also shown that a low resistance to acid attack is associated with a large amount of magnesium and/or iron in the stone.

scholarly journals Corrosion Inhibitory Effects of Mullite in Concrete Exposed to Sulfuric Acid Attack

2020 ◽  
Vol 1 (2) ◽  
pp. 282-295
Author(s):  
Shima Taheri ◽  
Gerardo Pareja Delgado ◽  
Oluwatoosin B. A. Agbaje ◽  
Paritosh Giri ◽  
Simon Martin Clark
Keyword(s):  
Sulfuric Acid ◽  
Prolonged Exposure ◽  
Acid Corrosion ◽  
Hardness Test ◽  
Aluminum Silicate ◽  
Acid Attack ◽  
Concrete Pipes ◽  
Physicochemical Changes ◽  
Sulfuric Acid Solutions

Prolonged exposure to low pH conditions affects the durability of concrete. In this work, the effect of mullite, aluminum silicate, on the strength and the acid corrosion of mortar and concrete under induced accelerated conditions in sulfuric acid solutions at pH of 0.25 and 1 was studied. The characterization of physicochemical changes was performed using techniques including compressive strength, scanning electron microscopy, micro-X-ray fluorescence spectrometry, and the Vickers hardness test. The results indicate that the addition of mullite does not have any significant effect on the overall strength of mortar and concrete samples, while it significantly increases their resistance to corrosion caused by sulfate attack by 90%, therefore, it is expected to increase the life span and decrease the maintenance costs of concrete pipes subjected to acid corrosion in sewer environments. The inhibition efficiency is observed to be sensitive to acid concentration and was improved with increase in the amount of mullite in samples.

Mineralogical and physico-chemical characteristics of Cameroonian smectitic clays after treatment with weakly sulfuric acid

Clay Minerals ◽  
2015 ◽  
Vol 50 (5) ◽  
pp. 649-661 ◽  
Author(s):  
J.R. Mache ◽  
P. Signing ◽  
J.A. Mbey ◽  
A. Razafitianamaharavo ◽  
D. Njopwouo ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Structural Modification ◽  
Morphological Characteristics ◽  
Textural Properties ◽  
Exchange Capacity ◽  
Acid Solutions ◽  
Acid Attack ◽  
Physico Chemical ◽  
Dioctahedral Smectite ◽  
Sulfuric Acid Solutions

AbstractSmectitic clays from the Sabga and Bana areas, western Cameroon were treated with sulfuric-acid solutions of various concentrations – 0.5, 0.7, 1.0 and 4.0 N – at 80°C for 2 h. The mineralogical, physicochemical and morphological characteristics of the samples treated were analysed using several techniques. The sulfuric acid caused structural modification of the dioctahedral smectite. The accessory minerals such as cristobalite, quartz, feldspars and anatase remained unaltered by the acid attack. The supernatant solutions after acid treatment contain Mg, Ca, K, Na, Si, Al and Fe as a result of partial dissolution of octahedral and tetrahedral cations. The activated clay samples exhibited a smaller cation exchange capacity (CEC) and the specific surface area (SSA) increased with increasing concentration of sulfuric acid, ranging from 65 to 134 m2/g for the sample from Bana and from 74 to 84 m2/g for the sample from Sabga. The different SSAvalues were affected by the relative abundance of smectite and cristobalite (SiO2/Al2O3 = 2.2 and 6.5, respectively, from Bana and Sabga). The activated clays from Bana and Sabga displayed interesting physicochemical and textural properties and can be considered as promising adsorbents for the bleaching of vegetable oils.

Protection features of chromium-nickel steel in sulfuric acid solutions by triazole derivative

2019 ◽  
pp. 15-21
Author(s):  
Ya.G. Avdeev ◽  
◽  
Yu.B. Makarychev ◽  
D.S. Kuznetsov ◽  
L.P. Kazanskii ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Nickel Steel ◽  
Acid Solutions ◽  
Triazole Derivative ◽  
Sulfuric Acid Solutions

Electrochemistry of Gold in Aqueous Sulfuric Acid Solutions under Neural Stimulation Conditions

2005 ◽  
Vol 152 (7) ◽  
pp. E212 ◽  
Author(s):  
Daniel R. Merrill ◽  
Ionel C. Stefan ◽  
Daniel A. Scherson ◽  
J. Thomas Mortimer
Keyword(s):  
Sulfuric Acid ◽  
Neural Stimulation ◽  
Acid Solutions ◽  
Aqueous Sulfuric Acid ◽  
Sulfuric Acid Solutions

EXTRACTION OF AMERICIUM (IV) BY DIOCTYLAMINE PROM SULFURIC ACID SOLUTIONS CONTAINING A COMPLETING AGENT

1985 ◽  
Vol 3 (4) ◽  
pp. 417-426 ◽  
Author(s):  
B.F. Myasoedov ◽  
M.S. Milyukova ◽  
D.A. Malikov ◽  
Ye.V. Kuzovkina ◽  
N.S. Varezhkina
Keyword(s):  
Sulfuric Acid ◽  
Acid Solutions ◽  
Sulfuric Acid Solutions
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