scholarly journals HYDROTHERMAL EXTRACTION OF LITHIUM COMPOUNDS FROM PETALITE Li[AlSi4O10]

2021 ◽  
Vol 87 (11) ◽  
pp. 45-54
Author(s):  
Oleksandr Ivanenko ◽  
Tamara Pavlenko

Based on studies of the decomposition of pe­ta­lite ore, the hydrothermal method for the extraction of lithium and aluminum compounds from lithium aluminosilicate Li[AlSi4O10] (petalite) has been developed. The studied sample of ore contains, wt. %: Li2O – 0.75 and Al2O3 – 14.65. For unenriched petalite ore with low lithium content, it is proposed to use the hydrochemical method of aluminosilicate processing – Ponomarev – Sazhin method. According to this method, the decomposition of ore is carried out directly in autoclaves by chemical interaction of ore components with NaOH solution in the presence of calcium oxide. The conditions (high temperature and pressure) for the destruction of petalite and the transition of lithium into the liquid phase are created exactly in the hydrothermal process. In this case, lithium and aluminum compounds pass into the solution, and calcium and silicon form a partially soluble compound in the solid phase – sodium-calcium hydrosilicateNa2O·2CaO·2SiO2·2H2O. The degree of extraction of lithium reaches 89–94 %, aluminum reaches 77–95 % within 1 hour at a tempe­rature of 240–280 °C, given caustic modulus 14–18, the concentration of the initial solution of 400–450 g/dm3 of Na2O and the ratio of CaO : SiO2 = 1 : 1 in the reaction mixture. Aluminate or lithium carbonate and other compounds can be obtained from an aluminate solution containing 1.5–2.5 g/dm3 of Li2O and 32–44 g/dm3 of Al2O3. The solid phase formed as a result of decomposition, with a high degree of extraction of lithium from the ore contains a small amount of Li2O in its composition and therefore can be used in the cement industry. Depending on the quality of the decomposed raw material, the course of the hydrothermal process is influenced by a set of factors. With a small content of lithium and aluminum in the ore, the caustic modulus of aluminate solutions (αк = 1,645*Na2O/Al2O3) formed after decomposition is important. Its calculation is required in order to determine the amount of alkaline solution of the required concentration to ensure almost complete decomposition of the ore. This value should be higher the lower the decomposition temperature and the concentration of the initial solution to achieve the same degree of recovery of useful components in the liquid phase. With the same caustic modulus, the efficiency of ore decomposition increases significantly with increasing process temperature and increasing the concentration of the initial solution. This can be seen in the values of the degree of extraction of aluminum, which increases by 12 % with increasing temperature from 240 to 280 °C, while the extraction of lithium remains practically unchanged.

Author(s):  
N. A. Bulychev

In this paper, the plasma discharge in a high-pressure fluid stream in order to produce gaseous hydrogen was studied. Methods and equipment have been developed for the excitation of a plasma discharge in a stream of liquid medium. The fluid flow under excessive pressure is directed to a hydrodynamic emitter located at the reactor inlet where a supersonic two-phase vapor-liquid flow under reduced pressure is formed in the liquid due to the pressure drop and decrease in the flow enthalpy. Electrodes are located in the reactor where an electric field is created using an external power source (the strength of the field exceeds the breakdown threshold of this two-phase medium) leading to theinitiation of a low-temperature glow quasi-stationary plasma discharge.A theoretical estimation of the parameters of this type of discharge has been carried out. It is shown that the lowtemperature plasma initiated under the flow conditions of a liquid-phase medium in the discharge gap between the electrodes can effectively decompose the hydrogen-containing molecules of organic compounds in a liquid with the formation of gaseous products where the content of hydrogen is more than 90%. In the process simulation, theoretical calculations of the voltage and discharge current were also made which are in good agreement with the experimental data. The reaction unit used in the experiments was of a volume of 50 ml and reaction capacity appeared to be about 1.5 liters of hydrogen per minute when using a mixture of oxygen-containing organic compounds as a raw material. During their decomposition in plasma, solid-phase products are also formed in insignificant amounts: carbon nanoparticles and oxide nanoparticles of discharge electrode materials.


2016 ◽  
Vol 256 ◽  
pp. 63-68
Author(s):  
Davi Munhoz Benati ◽  
Kazuhiro Ito ◽  
Kazuyuki Kohama ◽  
Hajime Yamamoto ◽  
Eugênio José Zoqui

Fe-2.5C-1.5Si gray cast iron evaluated in previous works exhibited promising potential as semisolid raw material presenting low levels of maximum stress and viscosity, similar to Al-Si alloys. This work is intended to investigate phase transformations and liquid phase formation for the Fe-2.5C-1.5Si gray cast iron in order to understand the performance of the alloy during the semisolid processing. Thus in situ heating experiments via high temperature laser scanning confocal microscopy were performed to analyze the solid-to-liquid transition. At room temperature alloy presented a matrix of pearlite and ferrite with type D flake graphite. During the heating process the main transformations observed were graphite precipitation on the austenite grain boundaries, graphite precipitates and flakes graphite growing and coarsening with the increasing of temperature and the beginning of melt around 1140°C. Coarsened flakes at high temperatures resulted in a liquid continuous network after melting, thereby the liquid phase was formed surrounding and wetting homogeneously the solid phase. This favors the detachment of grains from each other and leads to the intended solid globules immersed in liquid.


Author(s):  
Oleg Burdo ◽  
◽  
Ilya Sirotyuk ◽  
Maxim Shcherbich ◽  
Aleksandr Akimov ◽  
...  

The researchings of raw material dehydration and extraction are analyzed. The energy problems of product dehydration processes are analyzed. It is shown that recent trends in the development of heat and mass transfer technology are associated with the use of electromagnetic energy generators. The aim of the work is reduction of energy consumption during liquid phase removing from solid plant raw material and reduction of product losses from oil-containing food-industry waste. Achievement of this aim lies with a hypothesis that the use of electromagnetic energy sources in the process of removing moisture from food raw material containing a solid phase will allow to form an additional flow of the liquid phase, in addition to the traditional outlet of the vapor phase. The driving force of such a flow is the effect resulting from the local dissipation of electromagnetic energy in the solid phase volume. A mathematical model of the dehydration process is presented and a set of experimental studies was carried out, which confirmed the validity of the hypothesis. The most significant result of the work is proof of the possibility to organize modes when the juice yield is 4 times higher than the steam yield and, accordingly, to reduce energy consumption for product dehydration. The scientific significance of the obtained results is that a new effect was obtained in the work, which the authors called parodynamic. The practical significance of the work consists of proposing of the technological line for processing oilcontaining waste: coffee sludge, coffee beans husk, reagents (clay and perlite).


2018 ◽  
Vol 156 ◽  
pp. 05002 ◽  
Author(s):  
Endang Sri Rahayu ◽  
Gatot Subiyanto ◽  
Arief Imanuddin ◽  
Wiranto ◽  
Sabrina Nadina ◽  
...  

Kaolin is the clay mineral which containing silica (SiO2) and alumina (Al2O3) in a high percentage, that can be used as a nutrient in the synthesis of zeolites and amorphous silica alumina (ASA). The objective of this research is to convert the Belitung kaolin into silica and alumina as nutrients for the synthesis of zeolites and amorphous silica alumina, which are required in the preparation of the catalysts. Silica and alumina contained in the kaolin were separated by leaching the active kaolin called as metakaolin, using HCL solution, giving a solid phase rich silica and a liquid phase rich alumina. The solid phase rich silica was synthesized to zeolite Y by adding seed of the Y Lynde type, through the hydrothermal process with an alkaline condition. While, the liquid phase rich alumina was converted into an amorphous silica alumina through a co precipitation method. Characterization of zeolite and ASA were done using XRD, surface area and pore analyzer and SEM. The higher of alumina in liquid phase as a result of the rising molar of HCL in the leaching process was observed, but it didn’t work for its rising time. Products of ASA and zeolite Y were obtained by using liquid phase rich alumina and solid phase rich silica, respectively, which resulted through leaching metakaolin in 2.5 M HCl at temperature of 100° C for 2 hours.


Author(s):  
C.D. Humphrey ◽  
T.L. Cromeans ◽  
E.H. Cook ◽  
D.W. Bradley

There is a variety of methods available for the rapid detection and identification of viruses by electron microscopy as described in several reviews. The predominant techniques are classified as direct electron microscopy (DEM), immune electron microscopy (IEM), liquid phase immune electron microscopy (LPIEM) and solid phase immune electron microscopy (SPIEM). Each technique has inherent strengths and weaknesses. However, in recent years, the most progress for identifying viruses has been realized by the utilization of SPIEM.


Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 386
Author(s):  
Natalia Matłok ◽  
Józef Gorzelany ◽  
Adam Figiel ◽  
Maciej Balawejder

The study presents the effects of fertilisation on selected quality parameters of the dried material obtained from plants of lovage and coriander. During the crop production process, the plants were treated with two fertilisers containing substances potentially acting as elicitors. The dried material was obtained in course of a drying process carried out in optimum conditions and based on the CD-VMFD method which combines convective pre-drying (CD) at a low temperature (40 °C) with vacuum-microwave finish drying with the use of 240 W microwaves (VMFD). The quality of the dried material was evaluated through measurement of the total contents of polyphenols, total antioxidant potential (ABTS and DPPH method), and the profile of volatile compounds (headspace-solid phase microextractio-HS-SPME) as well as assessment of the colour. It was found that by applying first fertilisation (with organic components) it is possible to significantly increase the contents of both bioactive compounds and volatile substances responsible for the aroma. It was determined that the higher content of bioactive compounds was related to the composition of the first fertiliser, presumably the extract from common nettle. The study showed that the application of the first fertiliser contributed to enhanced quality parameters of the raw material obtained.


Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1014
Author(s):  
Macy L. Sprunger ◽  
Meredith E. Jackrel

Aberrant protein folding underpins many neurodegenerative diseases as well as certain myopathies and cancers. Protein misfolding can be driven by the presence of distinctive prion and prion-like regions within certain proteins. These prion and prion-like regions have also been found to drive liquid-liquid phase separation. Liquid-liquid phase separation is thought to be an important physiological process, but one that is prone to malfunction. Thus, aberrant liquid-to-solid phase transitions may drive protein aggregation and fibrillization, which could give rise to pathological inclusions. Here, we review prions and prion-like proteins, their roles in phase separation and disease, as well as potential therapeutic approaches to counter aberrant phase transitions.


2000 ◽  
Vol 2000 ◽  
pp. 144-144
Author(s):  
A.J. Ayala-Burgos ◽  
F.D.DeB. Hovell ◽  
R.M. Godoy ◽  
Hamana S. Saidén ◽  
R. López ◽  
...  

Cattle in the tropics mostly depend on pastures. During dry periods the forage available is usually mature, constraining both intake and digestion. These constraints need to be understood, for intake and digestibility define productivity. Intake depends on the rumen space made available by fermentation and outflow. Markers such as PEG (liquid phase), and chromium mordanted fibre (solid phase) can be used to measure rumen volume and outflow, but have limitations. The objective of this experiment was to measure intake, digestibility, and rumen kinetics of cattle fed ad libitum forages with very different degradation characteristics, and also to compare rumen volumes measured with markers with those obtained by manual emptying.


1998 ◽  
Vol 22 ◽  
pp. 306-308
Author(s):  
M. D. Carro ◽  
E. L. Miller

The estimation of rumen microbial protein synthesis is one of the main points in the nitrogen (N)-rationing systems for ruminants, as microbial protein provides proportionately 0.4 to 0.9 of amino acids entering the small intestine in ruminants receiving conventional diets (Russell et al., 1992). Methods of estimating microbial protein synthesis rely on marker techniques in which a particular microbial constituent is related to the microbial N content. Marker : N values have generally been established in mixed bacteria isolated from the liquid fraction of rumen digesta and it has been assumed that the same relationship holds in the total population leaving the rumen (Merry and McAllan, 1983). However, several studies have demonstrated differences in composition between solid-associated (SAB) and fluid-associated bacteria in vivo (Legay-Carmier and Bauchart, 1989) and in vitro (Molina Alcaide et al, 1996), as well in marker : N values (Pérez et al., 1996). This problem could be more pronounced in the in vitro semi-continuous culture system RUSITEC, in which there are three well defined components (a free liquid phase, a liquid phase associated with the solid phase and a solid phase), each one having associated microbial populations.The objective of this experiment was to investigate the effect of using different bacterial isolates (BI) on the estimation of microbial production of four different diets in RUSITEC (Czerkawski and Breckenridge, 1977), using (15NH4)2 SO4 as microbial marker, and to assess what effects any differences would have on the comparison of microbial protein synthesis between diets.This study was conducted in conjunction with an in vitro experiment described by Carro and Miller (1997). Two 14-day incubation trials were carried out with the rumen simulation technique RUSITEC (Czerkawski and Breckenridge, 1977). The general incubation procedure was the one described by Czerkawski and Breckenridge (1977) and more details about the procedures of this experiment are given elsewhere (Carro and Miller, 1997).


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