HYDROTHERMAL EXTRACTION OF LITHIUM COMPOUNDS FROM PETALITE Li[AlSi4O10]

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.

INNOVATIVE METHODS OF JOINT PROCESSING OF HEAD AND FUSEL FRACTION IN RECTIFIED ALCOHOL END BIOETHANOL PRODUCTION

With rising energy prices, the development and implementation of innovative energy-saving technologies is a priority in the production of rectified alcohol and bioethanol. By-products of distillation are the head fraction of ethyl alcohol, fusel oil, and fusel alcohol. Existing methods of joint processing of the head and fusel fractions in one column do not provide effective removal together head and intermediate impurities, which adversely affects the quality of commercial alcohol. The aim of the work was to develop methods of joint processing of the head and fusel fractions in the column for the concentration of impurities of cyclic action, to determine the optimal technological parameters of the column, and to test the efficiency of innovative methods in production conditions: to determine the degree of extraction, the concentration of volatile impurities Three schemes of processing of the head and fusel fractions are given. The method I allowed to free the bottom products from the head and intermediate impurities of alcohol and use such a liquid for hydroselection in the epuration column. Method II allowed significantly improving the physicochemical parameters of the bottom water-alcohol products, improving the quality of rectified ethyl alcohol by more complete removal of volatile organic impurities from the zones of their maximum accumulation and reducing their content in the reflux entering the irrigation column. Method III allowed ensuring maximum removal of volatile head and intermediate impurities and reducing the loss of ethyl alcohol with the concentrate of impurities. The use of innovative methods allows for joint processing of the main and fusel fractions in the production of rectified alcohol and bioethanol, to increase the yield of marketable alcohol by 3.8%.

thorium(IV), sorbent, sorption, desorption, clay

The article considers the danger of thorium due to its radioactive toxicity. There has been proved the diversity of thorium compounds and the influence of thorium on a human body and the environment. A polymer chelating sorbent containing fragments of 4-amino - thiouracil has been investigated. An isotherm of thorium sorption with the sorbent is constructed and the optimal concentration conditions are determined: pH = 4; = 6 • 10–3 mol/l; Vob = 25 ml; msorb = 0.03 g; sorptive capacity (CE) = 1 163 mg/g. The degree of extraction of thorium(IV) ions under optimal conditions exceeds 95%. The developed technique was applied to extract thorium from clay. Studying sorption was carried out under static conditions using special equipment.

The Kinetic Aspects of the Dissolution of Slightly Soluble Lanthanoid Carbonates

The problem of the complex use of mineral raw materials is significant in the context of many industries. In the rare earth industry, in the context of limited traditional domestic reserves and dependence on imports of lanthanides, an unambiguous and comprehensive solution has not yet been developed. Promising areas include the involvement of technogenic raw materials in the industrial turnover. The present study examines the kinetics of the dissolution process of poorly soluble lanthanide compounds when changing the parameters of the system. The results obtained reflect the dependence of the degree of extraction of lanthanide on the following variable parameters of the system: temperature, concentration of the complexing agent, and intensity of mixing. On the basis of the experiment, the values of the activation energy and the reaction orders were calculated. The activation energy of the carbonate dissolution process, in kJ/mol, was as follows: 61.6 for cerium, 39.9 for neodymium, 45.4 for ytterbium. The apparent reaction orders of the carbonates are equal to one. The prospect of using the research results lies in the potential to create a mathematical model of the process of extracting a rare earth metal by the carbonate alkaline method.

SPECIAL FEATURES OF COPPER AND NICKEL SORPTION ON LOW-BASE ANIONITES

In the work, the regularities of the process of sorption of copper and nickel ions from model solutions by low-base anionites containing coordination secondary groups are investigated. The main kinetic and concentration coordination characteristics of the process of complexation of copper and nickel ions with ligand groups of a low-base sorbent are determined.Potentiometric titration shows that anionite contains low-base functional groups, the pK of which is equal to 7.2.It is established that the process of sorption of copper ions by low-base macroporous anionite is characterized by a high initial rate and rapid achievement of equilibrium, which ensures absorption of copper ions about 70% of the equilibrium values in the first 10- 15 minutes.The main parameters of the sorption process are determined. Analytical description of sorption isotherm in coordinates of Langmuir equation is carried out. It was shown that due to high rates, the degree of extraction from solutions with a concentration of 10- 15 mmol/l under equilibrium conditions reaches 99.6-98.3%.Studies of the sorption process in a dynamic mode showed the possibility of separating heavy metal ions from aqueous solutions on new low-base anionites.

Thermodynamic analysis of interaction of components in the SIO2-C system: improvement of technical silicon production technological process

In order to identify ways to improve the technological process of smelting metallic (crystalline) silicon of technical purity, a thermodynamic analysis of the interaction of components in the SiO2-C system is carried out that reveals the main factor in obtaining high-quality technical silicon is the elimination of superposition of the silicon carbonization process that is possible by carrying out a two-stage carbothermal reduction reaction, in that firstly the incomplete reduction of silica (SiO2) by solid carbon (C) is provided, accompanied by the release of new reacting gas components - SiO and CO, the subsequent interaction of which leads to the formation of the target product - technical silicon that is suitable for the production of modern solar energy converters. It is determined that main condition for highly efficient reduction reactions is the fine fractionness (<1 mm) of the used quartzite ore with keeping of a rational temperature range for its carbothermal reduction (1688-2000 K). It has been shown experimentally that the optimal technical solution for the implementation of this reduction process is to performt melting in a special plasma-chemical furnace-reactor with one liquid-metal subconducting electrode, with a reverse vertical feed of the reaction gases released at the first stage. The degree of extraction of silicon was on average 95%, and the degree of its purity was 97.2%.

Beta-Carotene Extraction in Complex Food Additives

Introduction. Natural dye beta-carotene E160a (pro-vitamin A) is part of many functional foods. Therefore, the total intake of beta-carotene must not exceed the tolerable upper intake level, i.e. 10 mg/day. E160a is also used in formulations of complex food additives. These products contain antioxidants, emulsifiers, preservatives, carriers, stabilizers, and thickeners, which makes it make difficult to isolate and determine the amount of beta-carotene. Complex food additives vary in composition, which, together with incomplete extraction and degradation of beta-carotene, results in inaccuracy of its determination. The present research reviewed various techniques of beta-carotene extraction from liquid and dry complex food additives. Study objects and methods. The study featured commercial samples of complex food additives containing beta-carotene. It was isolated from the samples by liquid extraction methods using organic solvents and their binary mixtures. The extraction was performed in a stirring device at 120 rpm and in a Bandelin Sonorex ultrasonic bath at 128 W and 35 kHz. The extraction continued until the samples were completely discolored. The list of solvents included chloroform, petroleum ether, hexane, acetone, ethanol, and their mixes. The experiment was based on high performance thin layer chromatography with Sorbfil sheet plates. The optical density was determined by spectrophotometry using a SHIMADZU UV-1800 device. Results and discussion. The extraction of beta-carotene from liquid samples with mechanical stirring at 120 rpm led to the formation of stable opaque emulsions, which made it difficult to determine the amount of beta-carotene. The emulsions were destroyed by ultrasound exposure for 30 min. The degree of extraction of beta-carotene from liquid emulsion systems (≥ 95%) was achieved by ultrasonic extraction with chloroform or a binary extractant based on mixes of acetone with chloroform, hexane, or petroleum ether in volumetric ratios of 1:1. When extracted from dry samples using chloroform or binary extractants, beta-carotene was not isolated or was not completely isolated. As a result, pre-dispersion of dry samples in water with stirring at 120 rpm was proposed. Ultrasonic treatment did not contribute to the dispersion of dry samples due to insufficient cavitation action. Ethanol, which is a solubilizer, increased the extractability of beta-carotene up to 98 %. The optimal results were achieved by adding a binary extractant (ethanol:chloroform in a 1:2 ratio) to an aqueous solution of the dry sample (1:3). The optimal elution systems were hexane:benzene (9.7:0.3), butanol:methyl ethyl ketone:ammonia 10 % (9:6:6), and petroleum ether:benzene:acetone:acetic acid (23.3:5.8:0.6:0.3). Conclusion. The article offers new methods of beta-carotene isolation from liquid and dry complex food additives of various composition and elution systems for carotene identification. The methods caused no degradation of beta-carotene during extraction and can be used to prepare samples of complex food additives for beta-carotene identification and quantitative analysis.

Development of methods for purification of individual biological active substances obtained from extracts of Hedysarum neglectum

Hedysarum neglectum is a forage plant. Xanthone glycoside - mangiferin is extracted from this plant and used for medicine "Alpizarin". In addition to substances of xanthone nature (mangiferin and isomangiferin) Hedysarum neglectum contains sugars, vitamins and provitamins, tannins; in the underground part it contains oligomeric catechins, isoflavonoids, butylphenols, alkaloids, tannins, flavonoids, saponins, coumarins, carbohydrates, vitamin C. For selecting optimal schemes of fractionization of substances, it is necessary to resort to multi-stage schemes of group-wide (preliminary) isolation and preparative accumulation. In particular cases, it is necessary to take into account the presence of concomitant substances, as well as the effectiveness and selectivity of the sorption-chromatographic technologies used. According to the results of the studies, the use of silica gel and sefadex LH-20 for the isolation of a complex of flavonoids and gallic acid is the most effective method for the selection of the optimal variant of the preparative isolation of the total amount of BAS in mcg/ml. The results of the research allowed us to identify the target biologically active substances with a degree of extraction of at least 80%: - fractions of xanthones, flavonoids, gallic acid.

Investigation of the influence of electromagnetic field strength on the quality of water purification from heavy metals by ferritization method

To date, one of the components of the global problem of water pollution has been the uncontrolled discharge of wastewater from industrial enterprises that use in their work technological solutions of heavy metals, including galvanic. Among the main components of wastewater generated in galvanic industrial enterprises, about 70% is zinc and its compounds, and the most toxic of the heavy metals contained in process solutions are Cr VI compounds. In view of this, it is important to improve the ferritization treatment of wastewater from zinc and chromium ions. A laboratory installation for the ferritization process with electromagnetic pulse activation (EMI) has been developed. This method of activation provides not only a reduction in energy costs, but also the appropriate degree of extraction of heavy metal ions, which allows you to get an aqueous solution that can be used in a circulating water supply system, and sludge disposed of as additives for alkaline cements. The influence of the strength of the electromagnetic field on the degree of extraction of zinc and chromium ions from wastewater by ferritization has been studied. It is determined that the best degree of purification from heavy metal ions is achieved at an electromagnetic field of 0.14T.

Analysis of individual biologically active compounds from root crop extracts of purple alfalfa (medicago sativa) in vitro

The authors selected the parameters for obtaining root cultures in vitro Medicago sativa. The number of cell culture lines studied is 15. The duration of the growth cycle is less than 50 days. The number of processed explants is 75. The growth characteristics of root cultures of in vitro purple alfalfa (Medicago sativa) were studied. The growth index for the dry biomass of the in vitro root culture of alfalfa was 31. A qualitative and quantitative analysis of the composition of BAS in the biomass of the obtained root cultures of in vitro alfalfa (Medicago sativa) was carried out. Unique biologically active substances (not previously described for alfalfa) were identified.): apigenin, naringenin, myricetin, chrysoeriol, coumestrol, and scopoletin. Rational parameters of isolation of individual BAS from the extract of root cultures of in vitro alfalfa (Medicago sativa) were selected. The degree of extraction of individual BAS is 80%. Methods of purification of individual BAS Medicago sativa have been developed. The degree of purification of individual BAS is 95%.