scholarly journals Dissolution profile of dolomite in chloric acid solution: The effect of chloric acid concentration and pulp density

2018 ◽  
Author(s):  
Solihin ◽  
Indriani ◽  
M. Zaki Mubarok
2019 ◽  
Vol 22 (1) ◽  
pp. 20-37
Author(s):  
Solihin Solihin ◽  
◽  
Pratama Arinaldo ◽  
Nanda Dewi ◽  
Haryadi Permana ◽  
...  

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 405
Author(s):  
Marlon L. Mopon ◽  
Jayson S. Garcia ◽  
Dexter M. Manguerra ◽  
Cyril John C. Narisma

Sulfuric acid anodization is one of the common methods used to improve corrosion resistance of aluminum alloys. Organic acids can be added to the sulfuric acid electrolyte in order to improve the properties of the anodized aluminum produced. In this study, the use of gallic acid as an additive to the sulfuric acid anodization of AA1100 was explored. The effect of varying anodization current density and gallic acid concentration on the properties of anodized aluminum samples was observed using electrochemical impedance spectroscopy, linear polarization, and scanning electron microscopy. It was observed that the corrosion resistance of samples anodized in gallic-sulfuric acid solution at 10 mA·cm−2 is lower than samples anodized in sulfuric acid. It was also observed that higher anodization current density can lead to lower corrosion resistances for aluminum samples anodized in gallic-sulfuric acid solution. However, samples anodized at 5 mA·cm−2 and at a gallic acid concentration of 5 g·L−1 showed better corrosion performance than the samples anodized in sulfuric acid only. This suggests that the use of low amounts of gallic acid as an additive for sulfuric acid anodization can lead to better corrosion resistances for anodized aluminum.


1957 ◽  
Vol 35 (5) ◽  
pp. 428-436 ◽  
Author(s):  
T. J. Hardwick

Identical values of the bimolecular rate constant of the ferrous ion – hydrogen peroxide reaction were obtained from intercomparisons of the methods previously used in following this reaction. In perchloric acid the bimolecular rate constant is unaffected by acid concentration; in sulphuric acid it increases slightly in acid concentrations above 10−2N. The results agree with and explain the differences between those obtained by Baxendale and by Dainton, but are only in marginal agreement with those recently reported by Weiss.


1984 ◽  
Vol 62 (1) ◽  
pp. 144-146 ◽  
Author(s):  
John T. Edward ◽  
Sin Cheong Wong ◽  
Robert A. McClelland

The rate of lactamization of benzylstrychnine in aqueous solution at 25 °C increases with acid concentration up to 5–10% sulfuric acid, and thereafter decreases. The maximum can be explained by taking account of the extent of protonation of the aromatic amino group with increasing acid concentration. This amino group is unusually weakly basic [Formula: see text], perhaps because it is locked in an extremely rigid cage structure which opposes the rehybridization of N which must take place when it is protonated.


1977 ◽  
Vol 30 (10) ◽  
pp. 2297
Author(s):  
BB Misra ◽  
SR Mohanty

The extraction of iron(III) from hydrochloric acid solution by the series of sulphoxides (R2SO) from dipentyl to didecyl sulphoxide in 1,1,2-trichloroethane has been studied. At a given strength of the extractant, extraction increases initially with increase in the acid concentration to a maximum at 8 M and decreases thereafter. Increase in H+ at constant Cl- strength or increase in Cl- at a given H+ increases the extraction. Under otherwise identical conditions, extraction increases with increase in the extractant concentration. The extracted species would appear to be HFeCl4,2R2SO. A mixture of two sulphoxides or of a sulphoxide and tributyl phosphate extracts the metal ion more than the sum of extractions due to the individual components.


Author(s):  
Owen Rhys Howell ◽  
Albert Jackson ◽  
Eric Keightley Rideal

The change in the absorption spectrum of cobalt chloride in aqueous solution with increasing concentration of hydrochloric acid at constant temperature (20° C) has already been investigated.* It was shown that with increasing concentration of acid up to 5N HCl, no blue constituent was formed. The cobalt atom, therefore, retains its six grouping over this range. The effect of increasing acid concentration is to replace two molecules of water by two atoms of chlorine: [Co(H 2 O) 6 ] → [Co(H 2 O) 4 Cl 2 ].


2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Francesco Ferella ◽  
Ida De Michelis ◽  
Francesca Beolchini ◽  
Valentina Innocenzi ◽  
Francesco Vegliò

The paper is focused on the recovery of zinc and manganese from alkaline and zinc-carbon spent batteries. Metals are extracted by sulphuric acid leaching in the presence of citric acid as reducing agent. Leaching tests are carried out according to a24full factorial design, and empirical equations for Mn and Zn extraction yields are determined from experimental data as a function of pulp density, sulphuric acid concentration, temperature, and citric acid concentration. The highest values experimentally observed for extraction yields were 97% of manganese and 100% of zinc, under the following operating conditions: temperature40∘C, pulp density 20%, sulphuric acid concentration 1.8 M, and citric acid 40 gL-1. A second series of leaching tests is also performed to derive other empirical models to predict zinc and manganese extraction. Precipitation tests, aimed both at investigating precipitation of zinc during leaching and at evaluating recovery options of zinc and manganese, show that a quantitative precipitation of zinc can be reached but a coprecipitation of nearly 30% of manganese also takes place. The achieved results allow to propose a battery recycling process based on a countercurrent reducing leaching by citric acid in sulphuric solution.


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