scholarly journals Obtaining selenium concentrate from the slime of the sulfuric acid workshop of the Balkhash copper plant and extracting selenium from it into solution

2020 ◽  
Vol 4 (315) ◽  
pp. 11-24
Author(s):  
A. N. Zagorodnyaya ◽  
◽  
A. S. Sharipova ◽  
X. A. Linnik ◽  
G. S. Ruzakhunova ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Sodium Hydroxide ◽  
Inductively Coupled Plasma ◽  
Large Scale ◽  
Sodium Sulfite ◽  
Sodium Hydroxide Solution ◽  
Colloidal Suspension ◽  
Copper Smelting ◽  
Elemental Selenium ◽  
Mercury Selenide

The article presents the results of large-scale laboratory tests of obtaining selenium concentrate from the slime of the sulfuric acid workshop (hereinafter: slime) of the Balkhash copper smelting plant and the extraction of selenium from it into solution. This slime, in contrast to similar slime from non-ferrous metallurgy plants, significantly differs in chemical and material compositions, especially in the selenium content (4.6 - 12.5 wt.%). Involving it in the production sphere will increase the production of selenium by more than 20% from that obtained by the plant from copper electrolyte slime. The slime is washed with water to remove sulfuric acid, dried at 105 ° C. Selenium concentrate was obtained by sequential leaching of slime with solutions of sodium carbonate and nitric acid, selenium from the concentrate was leached with solutions of sodium sulfite (atmospheric pressure) and sodium hydroxide (high pressure, autoclave leaching). Slime, concentrate, cakes, precipitates isolated from solutions, and solutions were analyzed using modern devices of a new generation: An Optima-8300 inductively coupled plasma spectrometer, an Axios X-ray fluorescence spectrometer, an Optima 2000 atomic emission spectroscope, a D8 Advance diffractometer, a D8 Advance infrared spectrometer Avatar 370. From the slime containing, wt. %: 51.2 Pb, 12.5 Se, 3.21 Hg and other elements, a selenium concentrate was obtained with the composition, wt. %: 0.41 Pb, 59.16 Se, 15.4 Hg. The technological indicators for obtaining a concentrate are given, %: concentrate yield - 20.74, Pb recovery - 0.81, Se - 98.23, Hg - 99.50. According to XRD and IR spectroscopy, the concentrate contains elemental selenium and mercury selenide from 10 selenium substances contained in the slime (given in the article). The extraction of selenium from the concentrate into the solution was, %: sodium sulfite - 76.84, sodium hydroxide - 89.65. The pulp from opening the concentrate with sodium hydroxide solution was filtered very poorly. The filtrates contained a colloidal suspension, which could not be filtered off either under vacuum or centrifugation. Therefore, to determine the qualitative and material composition of the filtrates, salts were obtained by evaporating a certain and then neutralized volume to dryness. It was found that only elemental selenium is leached from the concentrate by solutions of both reagents, while mercury selenide remains in the cakes. Moreover, over time, elemental selenium partially precipitated again from selenium-containing sodium sulfite solutions; the salts contain only elemental selenium. An explanation is given for the transition of soluble selenium salts to its elemental state. Despite the higher recovery of selenium from the concentrate by leaching in autoclaves, taking into account the equipment, the complexity of its maintenance, filtration of the pulp and the chemical composition of the filtrate, it is preferable to use the method of leaching with sodium sulfite.

Latex Battery Separators. Preparation and Properties

1937 ◽  
Vol 10 (2) ◽  
pp. 346-351
Author(s):  
H. W. Greenup ◽  
L. E. Olcott
Keyword(s):  
Sulfuric Acid ◽  
Sodium Hydroxide ◽  
Electrical Resistance ◽  
Sodium Hydroxide Solution ◽  
Storage Battery ◽  
Preliminary Treatment ◽  
Actual Contact ◽  
Dilute Sodium Hydroxide ◽  
Port Orford Cedar ◽  
Highly Porous

Abstract THE commonly used electrical storage battery consists of alternate negative plates of sponge lead and positive plates of lead peroxide immersed in an electrolyte, sulfuric acid; the whole is enclosed in a hard rubber or bituminous composition case. These plates are ordinarily separated from one another by ribbed sheets of wood called “separators.” The separators prevent short circuiting of the plates caused by actual contact of the plates with each other or by “treeing” (formation of lead crystals between the plates). The separators must be thin, in order to make the battery as compact as possible, and yet must be durable. It is necessary that they be highly porous so that their electrical resistance will be low, but the pores must be sufficiently fine so that “treeing” does not take place. Wood separators are ordinarily made of Port Orford cedar. They are usually given a preliminary treatment in warm, dilute sodium hydroxide solution to swell them, thus increasing their porosity, and to remove injurious substances which cause self-discharge and corrosion of the plates. Wood separators have the advantage of being inexpensive and of having fairly low electrical resistance, but they are not so resistant to the action of sulfuric acid and the oxidizing action in the cell as is desirable. They are, in many cases, the first part of the storage battery to fail and must then be replaced if the battery is to give further service.

Sulfate and Sulfuric Acid Resistance of Geopolymer Mortars Using Waste Blended Ash

2013 ◽  
Vol 61 (3) ◽  
Author(s):  
M. Aamer Rafique Bhutta ◽  
Nur Farhayu Ariffin ◽  
Mohd Warid Hussin ◽  
Nor Hasanah Abdul Shukor Lim
Keyword(s):  
Sulfuric Acid ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
Sodium Hydroxide Solution ◽  
Sodium Silicate Solution ◽  
Sulfate Solution ◽  
Mass Ratio ◽  
Palm Oil Fuel Ash ◽  
Fuel Ash

This paper presents the chemical resistance of geopolymer mortars prepared from the combination of palm oil fuel ash (POFA) and pulverized fuel ash (PFA) from agro–industrial waste as cement replacement and activated by alkaline solution. Alkaline solution was prepared by combining sodium silicate and sodium hydroxide. The concentration of alkaline solution used was 14 Molar. The optimum mix proportions of geopolymer mortars with PFA: POFA mass ratio of 70:30 was used together with alkaline solution. The ratio of sodium silicate solution–to–sodium hydroxide solution by mass was 2.5:1. The mass ratio of sand to blended ashes was 3:1. Test specimens 70×70×70 mm cube were prepared and cured at room temperature (28°C) for 28–d and heat–cured at 90°C for 24 h, respectively. Then specimens were exposed to 5% sodium sulfate solution and 2% sulfuric acid solution for 28–d, 56–d, 90–d, 180–d and 365–d .The evaluation was done by visual observation, mass change, and loss of compressive strength. The test results revealed that geopolymer mortars showed higher resistance to acids as compared to ordinary Portland cement mortar due to the elimination of cement in the mixture.

Microwave Assisted Enzymatic Hydrolysis of Corn Stalks for L-Lactic Acid Production

2010 ◽  
Vol 113-116 ◽  
pp. 712-715
Author(s):  
Xue Xin Yang ◽  
Gui Zhen Fang
Keyword(s):  
Lactic Acid ◽  
Sulfuric Acid ◽  
Enzymatic Hydrolysis ◽  
Sodium Hydroxide ◽  
Acid Production ◽  
Sodium Hydroxide Solution ◽  
Lactic Acid Production ◽  
Yield Ratio ◽  
Hydroxide Solution ◽  
Dilute Sodium Hydroxide

Glucose production from pretreated corn stalks by cellulose enzymatic hydrolysis with cellulase was investigated and compared with no pretreatment, as a reference. The corn stalks were pretreated with microwave, sulfuric acid hydrolysis and dilute sodium hydroxide solution hydrolysis respectively. The enzymatic hydrolysis experiments were carried out at 50°C, 50 g/l dry matter (DM) solid substrate concentration and 15 filter paper unit (IU)/g DM of a commercial cellulase. Fermentable sugar was able to be produced from all the pretreated corn stalks with an overall yield of 29-58% of the maximum theoretical yield, based on the glucan available in the solid and liquid substrate. The corn stalks pretreated with dilute acid had the best glucose yield as 58.09% followed by the corn stalks pretreated with acid and microwave with an overall yield of 57.02% with 15 IU/g DM of cellulase. Glucose was the main product with enzymatic hydrolysis yield ratio 38.89%in the dilute sulfuric acid pretreated corn stalks, while with enzymatic hydrolysis yield ratio 51.07%in the dilute sodium hydroxide solution and microwave pretreated corn stalks under enzymatic hydrolysis conditions. These advantages, along with their negative price, make these solids a valuable raw material for L-lactic acid production.

scholarly journals Technology development of fatty acids obtaining from soapstok using saponification

2021 ◽  
Vol 5 (6 (113)) ◽  
pp. 16-23
Author(s):  
Natalia Sytnik ◽  
Ekaterina Kunitsia ◽  
Viktoriia Kalyna ◽  
Olena Petukhova ◽  
Kostiantyn Ostapov ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Sulfuric Acid ◽  
Sodium Hydroxide ◽  
Mass Fraction ◽  
Sodium Hydroxide Solution ◽  
First Grade ◽  
Oil Refining ◽  
Two Stage ◽  
Hydroxide Solution ◽  
Total Fat

The processing of oil refining waste is essential from economic and environmental points of view. An important issue is the processing of soapstock to extract fatty acids, which are raw materials for various industries. The two-stage method of fatty acids obtaining from soapstock using saponification with sodium hydroxide solution and decomposition with sulfuric acid is investigated. The peculiarity of the work is the study of the influence of soapstock saponification conditions on the key efficiency indicators of fatty acid extraction: yield and neutralization number. A sample of soapstock was obtained as a result of alkaline neutralization of sunflower oil. Soapstock quality corresponds to DSTU 5033 (CAS 68952-95-4): mass fraction of total fat – 68.5 %, fatty acids – 62.6 %, neutral fat – 5.9 %. Rational saponification conditions were determined: duration (85 min.) and concentration of sodium hydroxide solution (45 %). After saponification, the soapstock was subjected to decomposition with sulfuric acid under the following conditions: temperature 90 °C, duration 40 min. Under the rational saponification conditions, the yield of fatty acids (91.8 %) and the neutralization number (187.1 mg KOH/g) were determined. The obtained fatty acids correspond to the first-grade fatty acids according to DSTU 4860 (CAS 61788-66-7). Acid indicators: mass fraction of moisture and volatile substances – 1.5 %, mass fraction of total fat – 98.0 %, cleavage depth – 69.2 % oleic acid. The use of the soapstock saponification stage before decomposition leads to an improvement in the quality indicators and an increase in the neutralization number of fatty acids by 4 %, yield – by 16.2 %. The results of the study make it possible to produce fatty acids from soapstock by two-stage technology with high yield and neutralization number

Pattern Writing by Implantation in a Large-Scale PSII System With Planar Inductively Coupled Plasma Source

2000 ◽  
Vol 624 ◽  
Author(s):  
Lingling Wu ◽  
Hongjun Gao ◽  
Dennis M. Manos
Keyword(s):  
Inductively Coupled Plasma ◽  
Large Scale ◽  
Lateral Diffusion ◽  
Plasma Source ◽  
Direct Writing ◽  
Large Area ◽  
Depth Profiles ◽  
Geometric Patterns ◽  
Planar Coil ◽  
Rf Antenna

ABSTRACTA large-scale plasma source immersion ion implantation (PSII) system with planar coil RFI plasma source has been used to study an inkless, deposition-free, mask-based surface conversion patterning as an alternative to direct writing techniques on large-area substrates by implantation. The apparatus has a 0.61 m ID and 0.51 m tall chamber, with a base pressure in the 10−8 Torr range, making it one of the largest PSII presently available. The system uses a 0.43 m ID planar rf antenna to produce dense plasma capable of large-area, uniform materials treatment. Metallic and semiconductor samples have been implanted through masks to produce small geometric patterns of interest for device manufacturing. Si gratings were also implanted to study application to smaller features. Samples are characterized by AES, TEM and variable-angle spectroscopic ellipsometry. Composition depth profiles obtained by AES and VASE are compared. Measured lateral and depth profiles are compared to the mask features to assess lateral diffusion, pattern transfer fidelity, and wall-effects. The paper also presents the results of MAGIC calculations of the flux and angle of ion trajectories through the boundary layer predicting the magnitude of flux as a function of 3-D location on objects in the expanding sheath

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