Anodic Dissolution Behaviour of Tungsten Carbide Scraps in Ammoniacal Media

2013 ◽  
Vol 828 ◽  
pp. 11-20 ◽  
Author(s):  
Prvan Kumar Katiyar ◽  
Navneet Singh Randhawa ◽  
Jhumki Hait ◽  
Ranajit Kumar Jana ◽  
K.K. Singh ◽  
...  
Keyword(s):  
Citric Acid ◽  
Hydrochloric Acid ◽  
Anodic Dissolution ◽  
Ammonium Carbonate ◽  
Aqueous Ammonia ◽  
Electrolytic Cell ◽  
The Other ◽  
Dissolution Behaviour ◽  
Acidic Electrolyte ◽  
Dissolution Current

In the present paper, potentiodynamic studies of WC scrap have been carried out as these studies give better idea about the anodic dissolution behaviour of the scrap material to recover the metal values. However, it has been seen that anodic passivation retards the dissolution of the scrap and adversely affects the recovery of metals. To minimize the passivity and to increase the anodic dissolution, some chemicals are often used as additives. Two different electrolytes namely hydrochloric acid and aqueous ammonia at varying concentrations had been employed for the above studies. The additives citric acid and oxalic acid were added to the acidic electrolyte whereas ammonium chloride, ammonium carbonate and ammonium sulphate were added in different concentration to the ammoniacal electrolyte. The studies revealed that 2% citric acid in 1N HCl was the optimum to achieve maximum anodic dissolution (current) of WC scrap. On the other hand, 5% NH4Cl was found suitable to obtain maximum anodic dissolution (current) in the ammoniacal (150 g/L) medium. The potentiodynamic studies were followed by the actual electrodissolution experiments in an electrolytic cell with the help of a rectifier. The W and Co recoveries were encouraging.

Extraction of iron, cobalt, nickel and copper with dibenzyl sulfoxide solution in toluene

1979 ◽  
Vol 44 (7) ◽  
pp. 2024-2031 ◽  
Author(s):  
František Vláčil ◽  
Huynh Dang Khanh
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Distribution Ratio ◽  
Separation Factor ◽  
Chromatographic Separation ◽  
The Other ◽  
Iron Cobalt ◽  
Cobalt Nickel ◽  
Factor Α

The dependence of the distribution ratio of the metal on the concentration of hydrochloric of nitric acid was examined for Fe, Co, Ni and Cu extraction with 0.05M solution of dibenzylsulfoxide in toluene. Iron is extracted considerably more than the other metals, and is better extracted from hydrochloric acid than from nitric acid. The separation factor αFe/M (for 8M-HCl) is of the order of 104; this is not sufficient for a separation of trace quantities of iron from Co, Ni and Cu, but even at lower concentrations of HCl (e.g., 5M) the values is high enough for extraction chromatographic separation. The composition of the iron solvate extracted from HCl or LiCl medium was determined to be HFeCl4.2 B (B = dibenzyl sulfoxide).

Two-step demineralization of shrimp (Pandalus Borealis) shells using citric acid: An environmentally friendly, safe and cost-effective alternative to the traditional approach

2021 ◽  
Author(s):  
Julia Pohling ◽  
Deepika Dave ◽  
Yi Liu ◽  
Wade Murphy ◽  
Sheila Trenholm
Keyword(s):  
Citric Acid ◽  
Hydrochloric Acid ◽  
Environmental Health ◽  
Traditional Approach ◽  
Health And Safety ◽  
Cost Effective ◽  
Environmental Health And Safety ◽  
Pandalus Borealis ◽  
Chitin Extraction ◽  
Cost Effective Alternative

Removal of minerals from crustacean shells during chitin extraction is traditionally achieved using hydrochloric acid. However, the environmental, health and safety concerns of hydrochloric acid have led to investigation of...

Effect of pH, Acidulant, Time, and Temperature on the Growth and Survival of Listeria monocytogenes

1989 ◽  
Vol 52 (8) ◽  
pp. 571-573 ◽  
Author(s):  
KENT M. SORRELLS ◽  
DAVIN C. ENIGL ◽  
JOHN R. HATFIELD
Keyword(s):  
Antimicrobial Activity ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Citric Acid ◽  
Hydrochloric Acid ◽  
Malic Acid ◽  
Incubation Temperature ◽  
Growth And Survival ◽  
Ph Values

The effect of different acids, pH, incubation time, and incubation temperature on the growth and survival of four strains of Listeria monocytogenes in tryptic soy broth was compared. Hydrochloric acid (HCl), acetic acid (AA), lactic acid (LA), malic acid (MA), and citric acid (CA) were used to acidify tryptic soy broth to pH values 4.4, 4.6, 4.8, 5.0, and 5.2 pH. Incubation times were 1, 3, 7, 14, and 28 d at 10, 25, and 35°C. The inhibition of L. monocytogenes in the presence of high acidity appears to be a function of acid and incubation temperature. Based on equal pH values, the antimicrobial activity is AA > LA > CA ≥ MA > HCl at all incubation times and temperatures. When based on equal molar concentration, the activity appeared to be CA ≥ MA > LA ≥ AA > HCl at 35 and 25°C, and MA > CA > AA ≥ LA > HCl at 10°C. Greatest antimicrobial activity occurred at 35°C. Greatest survival occurred at 10°C and greatest growth occurred at 25°C. Final pH of the medium was as low as 3.8 in HCl at 28 d. All strains grew well at pH values lower than the minimum previously reported (5.5–5.6).

GROWTH OF STAPHYLOCOCCUS AUREUS IN ACIDIFIED PASTEURIZED MILK1

1970 ◽  
Vol 33 (11) ◽  
pp. 516-520 ◽  
Author(s):  
T. E. Minor ◽  
E. H. Marth
Keyword(s):  
Staphylococcus Aureus ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Hydrochloric Acid ◽  
Ph Value ◽  
The Other ◽  
Antagonistic Effects ◽  
Pasteurized Milk ◽  
Ph Values ◽  
Effect On Growth

The effect of gradually reducing the pH of pasteurized milk with acetic, citric, hydrochloric, lactic, and phosphoric acids over periods of 4, 8, and 12 hr on growth of Staphylococcus aureus 100 in this substrate was determined. In addition, 1: 1 mixtures of lactic acid and each of the other acids, and of acetic and citric acids were evaluated for their effect on growth of this organism. To achieve a 90% reduction in growth over a 12 hr period, a final pH value of 5.2 was required for acetic, 4.9 for lactic, 4.7 for phosphoric and citric, and 4.6 for hydrochloric acid. A 99% reduction during a 12 hr period was obtained with a final pH value of 5.0 for acetic, 4.6 for lactic, 4.5 for citric, 4.1 for phosphoric, and 4.0 for hydrochloric acid. A pH value of 3.3 was required for a 99.9% reduction with hydrochloric acid, whereas the same effect was produced at a pH value of 4.9 with acetic acid. Correspondingly lower pH values were required to inhibit growth within 8 and 4 hr periods. Mixtures of acids adjusted to pH values at the borderline for growth (12 hr period) exhibited neither synergistic nor antagonistic effects between two acids.

A pilot plant for the removal of cationic fission products from milk: I. Design and construction

1968 ◽  
Vol 35 (2) ◽  
pp. 257-268 ◽  
Author(s):  
R. F. Glascock ◽  
H. S. Hall ◽  
S. F. Suffolk ◽  
D. T. W. Bryant
Keyword(s):  
Citric Acid ◽  
Ion Exchange ◽  
Pilot Plant ◽  
Potassium Hydroxide ◽  
Exchange Resin ◽  
Ionic Composition ◽  
Fission Products ◽  
Ion Exchange Resin ◽  
The Other ◽  
Design And Construction

SummaryA pilot plant with a capacity of 2300 1./5 h day for the removal of cationic fission products from milk is described. The process involves the acidification of the milk with citric acid to pH 5.25 and its passage through an ion exchange resin charged with the ions of Ca, K, Na and Mg in the same proportions as those in which they occur in milk. The effluent milk is neutralized with potassium hydroxide. At the end of the day the plant and resin bed are washed and sterilized.Two resin beds are provided and are used on alternate days, one being washed and regenerated while the other is in use. Regeneration is carried out with a solution which removes radioactive cations and restores the resin bed to its original ionic composition.Bacteriological tests show that the method of cleaning both plant and resin bed is satisfactory.Conclusions are drawn as to a suitable design for a larger scale plant.

Pyrimidine Derivatives and Related Compounds, V Synthesis of Some Isoxazolo [2,3-a] pyrimidines. A New Ring System

1977 ◽  
Vol 32 (3) ◽  
pp. 311-314 ◽  
Author(s):  
Mohamed Hilmy Elnagdi ◽  
Ezzat Mohamed Kandeel ◽  
Kamal Usef Sadek
Keyword(s):  
Acetic Acid ◽  
Hydrochloric Acid ◽  
Ethyl Acetoacetate ◽  
Pyrimidine Derivative ◽  
Ring System ◽  
The Other ◽  
Acid Mixture ◽  
Pyrimidine Derivatives ◽  
Benzoyl Isothiocyanates ◽  
Related Compounds

3-Amino-5-phenyl-4-phenylazoisoxazole (1) reacts with ethyl acetoacetate to yield the corresponding ethyl isoxazolylaminocrotonate derivative (2) which could be thermally cyclized into the isoxazolopyrimidine derivative (4). On the other hand, condensation of 1 with ethoxymethylenemalononitrile has resulted in the formation of the aminoethylene derivative (5).Compound 1 reacted with acrylonitrile to yield the isoxazolo[2,3-a]pyrimidine derivative (6). The latter was converted into the corresponding exo derivative (8) by the action of acetic acid-hydrochloric acid mixture.Compound 1 also reacted with methoxycarbonyl-, ethoxycarbomyl- and benzoyl isothiocyanates to yield the isoxazolylthioureas (10a, b) and (11), respectively. The reaction of 2 with acetic acid-hydrochloric acid and with phenylhydrazine is reported.

THE RELATIONSHIP BETWEEN NUTRITION AND ANDROGENIC ACTIVITY IN PUBESCENT TWIN CALVES, AND THE EFFECT OF ORCHITIS

1967 ◽  
Vol 38 (4) ◽  
pp. 455-NP ◽  
Author(s):  
T. MANN ◽  
L. E. A. ROWSON ◽  
R. V. SHORT ◽  
J. D. SKINNER
Keyword(s):  
Citric Acid ◽  
Control Animal ◽  
Inhibitory Effect ◽  
Seminal Vesicles ◽  
The Other ◽  
Identical Twin ◽  
Androgen Deficiency ◽  
Androgenic Activity ◽  
The Relationship

SUMMARY The inhibitory effect of underfeeding on the process of male pubescence was studied in three pairs of bovine identical twin calves by feeding one twin on a normal and the other on a low plane of nutrition. As a result of malnutrition the development of the androgenic function of the testes was retarded much more markedly than spermatogenesis. In the undernourished twin the testes contained and secreted less testosterone, and showed a lower testosterone: androstenedione ratio, than in the control animal. This nutritionally conditioned androgen deficiency was clearly reflected in a markedly retarded onset of production of fructose and citric acid by the seminal vesicles. After castration the underfed twin responded to testosterone injections much more sluggishly than the control twin, as shown by the delayed appearance of fructose and citric acid in electrically-induced ejaculates. Observations were also made on the effects of orchitis and cryptorchidism. Both these conditions lowered markedly the androgenic activity in the calves.

scholarly journals III. On the preparation of ethylamine

1867 ◽  
Vol 15 ◽  
pp. 218-220
Keyword(s):  
Hydrochloric Acid ◽  
Dilute Hydrochloric Acid ◽  
Aqueous Ammonia ◽  
Moderate Temperature

Having recently had occasion to prepare a considerable quantity of ethylamine, we have made the observation that this base may be obtained with much greater facility than is usually believed. We digested together equal volumes of iodide of ethyl, strong alcohol, and aqueous ammonia. The digestion was carried on at a very moderate temperature, certainly not exceeding 80°, but the tubes were constantly agitated. In this manner the reaction is completed in about half an hour. The mixed iodides thus obtained were evaporated to expel excess of ammonia, introduced into a retort; enough potash was added to neutralize 1/10 of the iodine present, and the mixture was distilled into dilute hydrochloric acid. The receiver was then changed, the same quantity of potash again added, and the products collected as before. Then six times as much potash was added, and the products collected. The remaining two-tenths of the potash were added separately.

THE STABILITY OF CYANOGEN CHLORIDE

1947 ◽  
Vol 25f (5) ◽  
pp. 284-290 ◽  
Author(s):  
A. B. Van Cleave ◽  
R. L. Eager
Keyword(s):  
Hydrochloric Acid ◽  
Decomposition Reaction ◽  
The Other ◽  
Pyrex Glass ◽  
Cyanogen Chloride ◽  
The Stability ◽  
Container Material

The stability of cyanogen chloride in contact with Pyrex glass, aluminium, bakelite, brass, and steel at 20 °C. has been investigated. The tests indicate that crude or purified cyanogen chloride can be satisfactorily and safely stored in contact with any of these materials except brass, provided that precautions are taken to ensure that only relatively small amounts of water or hydrochloric acid are present. Brass has been shown to be entirely unsatisfactory as a container material for either crude or pure cyanogen chloride as it appears to catalyse a decomposition reaction that is not shown by any of the other materials tested.

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