Optimal conditions for the reduction of selenate to selenite by hydrochloric acid

1988 ◽  
Vol 332 (3) ◽  
pp. 242-244 ◽  
Author(s):  
Ragnar Bye ◽  
Walter Lund
2013 ◽  
Vol 734-737 ◽  
pp. 1033-1036
Author(s):  
Gui Fang Zhang ◽  
Peng Yan ◽  
Qing Rong Yang

Based on the benefication of the complex silicate ore containing scandium, the research about aid-leaching agent used in the leaching of the scandium concentrate was been conducted. And the suitable leaching agent and aid-leaching agent which the useful ions entered into leaching liquid and the harmful ions were kept in leaching residue were been found according to the experiment results. For the scandium of sample existed various complex silicate ore as isomorphism form, the research has adopted hydrochloric acid with aid-leaching agent to dissociate the silicate ore and make scandium entering into solution. The research results has shown that the scandium leaching rate could reach 92.06% under the optimal conditions which the hydrochloric acid concentration is 22.8%, the dosage of aid leaching agent is 6%, liquid solid ratio is 4:1, particle size of leaching material totally is less than 0.15mm and leaching time is 8h.


2013 ◽  
Vol 395-396 ◽  
pp. 601-604
Author(s):  
Jian Lan Suo

Objective: Optimizing the extraction of total alkaloids from Caulophyllum robustum. Methods: The taspine which is a type of alkaloids of Caulophyllum robustum is selected as the target index. First, developing the HPLC analysis protocol; second, using orthogonal design method to optimize the hydrochloric acid leaching protocol; third, using cation exchange column to isolate the alkaloids and examining the optimal conditions. Results: the optimal conditions of hydrochloric acid leaching protocol is using 7 column volume of 1% hydrochloric acid for 3 times. The materials are loaded onto the LSD001 cation exchange column with optimal pH 4 and flowrate 2ml/mL, the elution buffer is 10 column volume 5% hydrochloric acid. After desalting, the yield of alkaloids is 1.35% which includes 6.83% of taspine.


1960 ◽  
Vol 38 (1) ◽  
pp. 1235-1248 ◽  
Author(s):  
L. Gyenes ◽  
A. H. Sehon

Antigenically specific adsorbents were prepared by coupling soluble protein antigens to a polystyrene-supporting medium by azo bonds. These immunosorbents were shown to combine specifically with homologous precipitating rabbit antibodies. Elution of precipitating antibodies from the immunosorbents was achieved by dissociation with hydrochloric acid at pH 3. Under optimal conditions 35% of the antibodies removed from the antisera were recovered with a purity of over 80%. Electrophoretic analyses showed that precipitating rabbit antibodies were localized primarily in the region of gamma-globulins. The heterogeneity of the antigen–antibody systems studied was demonstrated by a combination of immunochemical, physicochemical, and radioactive tracer methods.


Author(s):  
Vladimir A. Levdansky ◽  
Alexander A. Kondrasenko ◽  
Alexander V.; Levdansky ◽  
Maxim A. Lutoshkin

The process of proanthocyanidins isolation from abies bark by water and water-alcohol solutions containing 5, 10, 15 and 20 % ethanol was studied for the first time. The optimal conditions providing the maximum yield of proanthocyanidins were determined experimentally. It was shown that the use of 15-20 % water-alcohol solutions allows to increase the yield of proanthocyanidins from 0.33 to 0.38 %. The composition of the obtained proanthocyanidins was studied by UV, IR, and 13C NMR spectroscopy. The obtained proanthocyanidins were transformed into colored anthocyanidins in ethanol medium in the presence of hydrochloric acid. The flavonoids cyanidin and delphinidin were isolated and identified. It was established that the obtained proanthocyanidins mainly consist of procyanidin and prodelphinidin. It was shown that proanthocyanidins obtained from abies bark, in contrast to the proanthocyanidins isolated from pine bark described in the literature, contain gallic acid residues, which is typical for proanthocyanidins isolated from various types of tea


Author(s):  
V. V. Shevchuk ◽  
T. N. Potkina ◽  
O. V. Smetanina

Due to the fact that polyhalite ores are poorly soluble in water, it was of interest to study the method of their processing using acids. The influence of polyhalite size, the hydrochloric acid concentration and consumption, the ratio of L: S, the temperature and time of mixing the pulp on the useful components extraction into the solution have been studied. The optimal conditions for the decomposition of polyhalite with hydrochloric acid have been determined. The degree of useful components extraction into the solution depends on the concentration of hydrochloric acid or on the L:S ratio of the pulp, but in all cases the decomposition of polyhalite occurs without secondary crystal formation, as evidenced by the same degree of potassium and magnesium ions extraction. The degree of potassium and magnesium ions extraction from polyhalite into solution increases with decomposition process temperature, an increase in the consumption of acid and the duration of the reagents interaction, and decreases with increasing acid concentration. The CaSO4 content in the solution increases sharply with an increase in the HCl concentration and is practically independent of the process temperature. Hydrochloric acid extract can be used for phosphate raw decomposition in order to obtain complex fertilizers.


2021 ◽  
pp. 225-229
Author(s):  
Evgeniy Evgen'yevich Kurdyukov ◽  
Ольга Александровна Vodop'yanova ◽  
Natalia Victorovna Antropova ◽  
Aleksandr Vladimirovich Mitishev ◽  
Natal'ya Evgen'yevna Evgrashkina

Fruits of Euterpe oleracea are widely used in foreign medical practice as an antioxidant. The fruits of Euterpe contain tannins. The most common method of quantitative determination of tannins is spectrophotometry. The purpose of this work is to determine the content of the sum of tannins in the fruits of Euterpe by spectrophotometry Quantitative determination of the amount of tannins in the fruits of Euterpe by direct spectrophotometry was carried out. To confirm the presence of tannins in the fruits of Euterpe, qualitative reactions were used (1% solution of iron-ammonium alum, 1% solution of vanillin in concentrated hydrochloric acid). The presence of tannins was confirmed by direct spectrophotometry in extracts from euterpe fruits, the analytical maxima of the studied compounds were determined at about 282±2 nm, which corresponds to the maximum absorption of catechin. The optimal conditions for the extraction of tannins from the raw materials of this plant (extractant – ethyl alcohol 40%; the ratio of "raw material – extractant" – 1 : 100; extraction time – 60 minutes; the degree of grinding of raw materials – 1.0 mm) are justified. It was determined that the average error in determining the content of tannins in the fruits of euterpe with a confidence probability of 95% is ±1.59%. It was revealed that the content of tannins in the fruits of euterpe is 8.90%.


1960 ◽  
Vol 38 (11) ◽  
pp. 1235-1248 ◽  
Author(s):  
L. Gyenes ◽  
A. H. Sehon

Antigenically specific adsorbents were prepared by coupling soluble protein antigens to a polystyrene-supporting medium by azo bonds. These immunosorbents were shown to combine specifically with homologous precipitating rabbit antibodies. Elution of precipitating antibodies from the immunosorbents was achieved by dissociation with hydrochloric acid at pH 3. Under optimal conditions 35% of the antibodies removed from the antisera were recovered with a purity of over 80%. Electrophoretic analyses showed that precipitating rabbit antibodies were localized primarily in the region of gamma-globulins. The heterogeneity of the antigen–antibody systems studied was demonstrated by a combination of immunochemical, physicochemical, and radioactive tracer methods.


Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1369
Author(s):  
Tülay Türk ◽  
Zeynep Üçerler ◽  
Fırat Burat ◽  
Gülay Bulut ◽  
Murat Olgaç Kangal

Potassium, which is included in certain contents in the structure of K-feldspar minerals, has a very important function in the growth of plants. Turkey hosts the largest feldspar reserves in the world and is by far the leader in feldspar mining. The production of potassium salts from local natural sources can provide great contributions both socially and economically in the agriculture industry along with glass production, cleaning materials, paint, bleaching powders, and general laboratory purposes. In this study, potassium extraction from K-feldspar ore with an 8.42% K2O content was studied using chloridizing (CaCl2) roasting followed by water leaching. Initially, to produce wollastonite and calcite concentrates, froth flotation tests were conducted on wollastonite-calcite ore after comminution. Thus, wollastonite and calcite concentrates with purities of 99.4% and 91.96% were successfully produced. Then, a calcite concentrate was combined with hydrochloric acid (HCl) under optimal conditions of a 1 mol/L HCl acid concentration, a 60 °C leaching temperature, and a 10 min leaching time to produce CaCl2. To bring out the importance of roasting before the dissolution process, different parameters such as roasting temperature, duration, and feldspar—CaCl2 ratios were tested. Under optimal conditions (a 900 °C roasting temperature, a 60 min duration, and a 1:1.5 feldspar—CaCl2 ratio), 98.6% of the potassium was successfully extracted by the water leaching process described in this article.


2003 ◽  
Vol 68 (2) ◽  
pp. 131-136 ◽  
Author(s):  
Aleksandar Igov ◽  
Ranko Simonovic ◽  
Rangel Igov

A new catalytic reaction is proposed and a kinetic method developed for the determination of ultramicro amounts of As(III) on the basis of its catalytic activity in the oxidation of ethylenediamine-N,N?-diacetic-N,N? dipropionic acid (EAP) by KMnO4 in the presence of hydrochloric acid. Under optimal conditions, the sensitivity of the method is 20 ng/cm3. The probable relative error is 7.6 ? 14.5 % for the concentration range 50 ? 200 ng/cm3 As(III). The effect of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. The method has relatively good selectivity. Kinetic equations were proposed for the investigated process.


2013 ◽  
Vol 807-809 ◽  
pp. 2440-2443
Author(s):  
Gui Fang Zhang ◽  
Peng Yan ◽  
Qing Rong Yang

The scandium concentrate used in the leaching experiment was obtained from the rare earth ore containing scandium in Yunnan Province, the sample used in experiment is leaching liquid containing scandium which the content of scandium is 3.6g/t, with complex impurity composition. The main influencing factors of extraction in hydrochloric acid solution were acidity, mixing time, phase ratio etc. and the condition experiments about these factors were conducted. The results show that extraction of scandium from the hydrochloric acid solution in TBP is feasible. The optimal conditions are that pH of the solution is 1.26, dosage of TBP is 5% of the solution, dosage of kerosene is 10% of TBP, mixing time is 3 min, phase ratio is 1:10, washing time is 2, the oscillating time of stripping is 1~2 min and the stripping rate reach 99.89%.


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