Contributions to the Analysis of Rubber. IV. Determination of Manganese in Crude Rubber; in Rubber Mixtures and in Fillers

1940 ◽  
Vol 13 (2) ◽  
pp. 430-436
Author(s):  
P. Dekker
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Reliable Method ◽  
Orthophosphoric Acid ◽  
Manganese Ions ◽  
Potassium Periodate ◽  
Mineral Fillers ◽  
Manganese Compounds

Abstract A scheme for the determination of manganese in mineral fillers, compounding ingredients, crude rubber, rubber mixtures and rubberized materials is described. It is shown that with this method the use of potassium persulfate and two drops of orthophosphoric acid, as proposed by Kehren for the oxidation of colorless manganese ions to red permanganate ions, is advisable. When potassium periodate is used, small quantities of manganese escape detection. It is further shown that there is no appreciable difference between concentration with nitric acid and evaporation with hydrochloric acid and a little sulfuric acid. If, however, the ash is decomposed by soda-potash mixture, the manganese contents are considerably higher. Doubtless these higher values can be accounted for by manganese compounds which are occluded in silicates, and which can be regarded as harmless. A reliable method for the decomposition of the manganese compounds is therefore desirable. The results of analyses of the manganese contents of a large number of various materials are tabulated, and the maximum manganese contents of various materials allowed by the Netherlands Government Rubber Institute are given.

The Rapid Semimicrovolumetric Determination of Sulfur in Natural and Synthetic Rubber Vulcanizates

1957 ◽  
Vol 30 (1) ◽  
pp. 354-361 ◽  
Author(s):  
Bella B. Bauminger
Keyword(s):  
Zinc Oxide ◽  
Sulfuric Acid ◽  
Hydrochloric Acid ◽  
Schematic Diagram ◽  
Total Sulfur ◽  
Synthetic Rubber ◽  
Combustion Apparatus ◽  
Mineral Fillers ◽  
A Current

Abstract In the first part, a modified form of combustion apparatus for sulfur analyses is described, and the principle of the method and the apparatus itself are illustrated by a schematic diagram. In the determination of sulfur in natural-rubber, Butyl-rubber, and Krylene mixtures which contain no mineral fillers such as barytes and whiting, 50 mg. of finely divided vulcanizate is covered with aluminum oxide, decomposed in a current of oxygen at 1000° C, and the sulfuric acid formed is determined gravimetrically. An analysis requires about 30 minutes. Differences between the analytical values obtained and the calculated values never amount to more than ±1 per cent. In the second part of the work, a newly developed procedure for the determination of total sulfur in rubber mixtures which contain barytes, lithopone, whiting, etc., is described. The sample is covered with a mixture of vanadium pentoxide and zinc oxide and is then decomposed in a current of oxygen at 1000° C Here too the sulfuric acid which is formed is titrated acidimetrically. An analysis requires about one hour. The final part of the work deals with a new method for the determination of sulfur in synthetic-rubber vulcanizates, such as Neoprene, Perbunan, Hypalon, etc. The sulfuric acid formed by their combustion is precipitated by a hydrochloric acid solution of 4-amino-4′-chlorobiphenyl, and titrated with sodium hydroxide. Zinc, chlorides, and nitrates have no disturbing effects on the reaction. The method was tested with vulcanizates of known compositions and was found to give satisfactory results.

DETERMINATION OF TRACE AMOUNTS OF SILVER IN GALENA ORES

1960 ◽  
Vol 38 (9) ◽  
pp. 1488-1494 ◽  
Author(s):  
E. J. Bounsall ◽  
W. A. E. McBryde
Keyword(s):  
Aqueous Solution ◽  
Nitric Acid ◽  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Silver Content ◽  
Aqueous Sodium Chloride Solution ◽  
Aqueous Sodium

An analytical method is described for the determination of microgram amounts of silver in galena ores, based on the "reversion" of silver dithizonate. Silver is separated from relatively large amounts of lead by extraction as dithizonate into chloroform from an aqueous 1:99 nitric acid solution. Separation from mercury, which is also extracted under these conditions and would, if present, interfere in the analysis, is achieved by reverting the dithizonate solution with a 5% aqueous sodium chloride solution which is also 0.015 molar in hydrochloric acid. Following dilution of this aqueous solution and adjustment of pH, silver is again extracted into chloroform as the dithizonate, and determined absorptiometrically. Analyses of a number of galena ore samples showed a precision of within 3% for a silver content ranging from 0.03 to 0.4%.Some other methods for isolating silver from these samples, which were tried but found unsatisfactory, are discussed.

scholarly journals Effect of Surface Modification with Different Acids on the Functional Groups of AF 5 Catalyst and Its Catalytic Effect on the Atmospheric Leaching of Enargite

2019 ◽  
Vol 3 (2) ◽  
pp. 45 ◽  
Author(s):  
Jahromi ◽  
Ghahreman
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Elemental Sulfur ◽  
Catalytic Properties ◽  
Copper Recovery ◽  
Pre Treatment ◽  
Sulfur Adsorption

Carbon-based catalysts can assist the oxidative leaching of sulfide minerals. Recently, we presented that AF 5 Lewatit® is among the catalysts with superior enargite oxidation capacity and capability to collect elemental sulfur on its surface. Herein, the effect of acid pre-treatment of the AF 5 catalyst was studied on the AF 5 surface, to further enhance the catalytic properties of AF 5. The AF 5 catalyst was pretreated by hydrochloric acid, nitric acid and sulfuric acid. The results showed that the acid treatment drastically changes the surface properties of AF 5. For instance, the concentration of quinone-like functional groups, which are ascribed to the catalytic properties of AF 5, is 45.4% in the sulfuric acid pre-treatment AF 5 and only 29.8% in the hydrochloric acid-treated AF 5. Based on the C 1s X-ray photoelectron spectroscopy (XPS) results the oxygenated carbon is 30.6% in the sulfuric acid-treated AF 5, 29.2% in the nitric acid-treated AF 5 and 28.3% in the hydrochloric acid-treated AF 5. The nitric acid pre-treated AF 5 resulted in the highest copper recovery during the oxidative enargite leaching process, recovering 98.8% of the copper. The sulfuric acid-treated AF 5 recovered 97.1% of the enargite copper into the leach solution. Among different leaching media and pre-treatment the lowest copper recovery was achieved with the HCl pre-treated AF 5 which was 88.6%. The pre-treatment of AF 5 with acids also had modified its elemental sulfur adsorption capacity, where the sulfur adsorption on AF 5 was increased from 30.9% for the HCl treated AF 5 to 51.1% for the sulfuric acid-treated AF 5.

The Effects of Acidic Medium on the Sodium Contents Determination by FAAS

2020 ◽  
Vol 1001 ◽  
pp. 139-144
Author(s):  
Ying Li ◽  
Ben Tao Li ◽  
Guang Yu Sun ◽  
Hui Huang ◽  
Chen Gong ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Atomic Absorption Spectrometry ◽  
Flame Atomic Absorption Spectrometry ◽  
Perchloric Acid ◽  
Acidic Medium ◽  
Absorption Spectrometry ◽  
Flame Atomic Absorption ◽  
Acid Effect

The influence of different acidic medium, including hydrochloric acid, nitric acid and perchloric acid on the absorbance of sodium by flame atomic absorption spectrometry was studied. The results showed that the effects of acidic medium and water on the determination of sodium were as follows: hydrochloric acid > perchloric acid > nitric acid > water. Acid effect changed with the increase of acid concentration, however, the absorbance value of sodium element decreased when the concentration of acid was higher than 1%~2%. This effect was more obvious for high content of sodium. The detection limits, repeatability and recovery of the samples under the three acidic medium were compared. The optimum acid conditions were determined and the sensitivity of the method was improved.

scholarly journals THE INACTIVATION OF DILUTE SOLUTIONS OF CRYSTALLINE TRYPSIN BY X-RADIATION

1955 ◽  
Vol 38 (5) ◽  
pp. 581-598 ◽  
Author(s):  
Margaret R. McDonald
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Radiation Effects ◽  
Reaction Yield ◽  
X Rays ◽  
Dilute Solutions ◽  
Experimental Conditions ◽  
Ph Range ◽  
Ph Curve

The proteolytic activity of dilute solutions of clystalline trypsin is destroyed by x-rays, the amount of inactivation being an exponential function of the radiation dose. The reaction yield increases steadily with increasing concentration of trypsin, varying, as the concentration of enzyme is increased from 1 to 300 µM, from 0.068 to 0.958 micromole of trypsin per liter inactivated per 1000 r with 0.005 N hydrochloric acid as the solvent, from 0.273 to 0.866 with 0.005 N sulfuric acid as the solvent, and from 0.343 to 0.844 with 0.005 N nitric acid as the solvent. When the reaction yields are plotted as a function of the initial concentration of trypsin, they fall on a curve given by the expression Y α XK, in which Y is the reaction yield, X is the concentration of trypsin, and K is a constant equal to 0.46, 0.20, and 0.16, respectively, with 0.005 N hydrochloric, sulfuric, and nitric acids as solvents. The differences between the reaction yields found with chloride and sulfate ions in I to 10 µM trypsin solutions are significant only in the pH range from 2 to 4. The amount of inactivation obtained with a given dose of x-rays depends on the pH of the solution being irradiated and the nature of the solvent. The reaction yield-pH curve is a symmetrical one, with minimum yields at about pH 7. Buffers such as acetate, citrate, borate and barbiturate, and other organic molecules such as ethanol and glucose, in concentrations as low as 20 µM, inhibit the inactivation of trypsin by x-radiation. Sigmoid inactivation-dose curves instead of exponential ones are obtained in the presence of ethanol. The reaction yields for the inactivation of trypsin solutions by x-rays are approximately 1.5 times greater when the irradiation is done at 26°C. than when it is done at 5°C., when 0.005 N hydrochloric acid is the solvent. The dependence on temperature is less when 0.005 N sulfuric acid is used, and is negligible with 0.005 N nitric acid. The difficulties involved in interpreting radiation effects in aqueous systems, and in comparing the results obtained under different experimental conditions, are discussed.

Background Spectral Features in Inductively Coupled Plasma/Mass Spectrometry

1986 ◽  
Vol 40 (4) ◽  
pp. 445-460 ◽  
Author(s):  
S. H. Tan ◽  
G. Horlick
Keyword(s):  
Mass Spectrometry ◽  
Sulfuric Acid ◽  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Inductively Coupled Plasma ◽  
Mass Spectra ◽  
Mass Range ◽  
Spectral Features ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry

Basic background mass spectra of the inductively coupled plasma are presented in this report. The background spectral features were measured for the nebulization of water and for 5% solutions of nitric acid, hydrochloric acid, and sulfuric acid. Background spectra are presented for all these solutions for the mass range 1 to 84 amu, and extensive tables are presented for observed species and their isotopic combinations.

The Inhibitor Exploration Test of Collophane Reverse Flotation in Yunnan

2014 ◽  
Vol 722 ◽  
pp. 22-24
Author(s):  
Bo Wen Yang ◽  
Ping Zhou ◽  
Wan Chao Jin
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Reverse Flotation ◽  
One Stage ◽  
Phosphate Product ◽  
Test Process

The phosphate is low silicon carbonate collophane, gangue mainly dolomite. determine one-stage roughing and one-stage scavenging reverse flotation test process,the grinding fineness of 92.86% -200 mesh.Collector with paraffin soap oxidated,Three acid of sulfuric acid, hydrochloric acid, nitric acid as an inhibitor for contrast test,With concentration of 10% sulfuric acid 10000 g/t can research qualified phosphate product with content of 33.95% in concentration and recovery of 62.06%.

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