Chemical Journal of Kazakhstan

EXTRACTION OF CHROME FROM FERROCHROME PRODUCTION SLAG USING THE SULFURIC ACID METHOD

2024-05-22T10:16:22+05:00

Introduction. Currently, the development of industrial waste recycling processes that reduce the anthropogenic load on the biosphere and ensure the rational use of natural resources is an urgent task. Technogenic waste from ferrochrome production contains chromium, which is one of the most toxic components of industrial waste. To extract chromium from them, the most acceptable method is acid leaching. The purpose of the work is to study the influence of temperature, process duration and H₂SO₄ concentration on the extraction of chromium from high-carbon ferrochrome slag into a sulfuric acid solution. Using mathematical planning of a 3-factor experiment, experiments were carried out to extract chromium from the slags of high-carbon ferrochrome production. The H₂SO₄ concentration was varied from 5 to 95% by diluting the concentrated acid. The duration of the process ranged from 10 to 180 minutes at S:L = 1:30, the temperature varied from 22 to 90 °C. Results and discussion. The maximum transition of chromium into acid occurs at a temperature of 76-90 °C and a process duration of 145-180 minutes. The degree of extraction reaches 97.9%. The smallest amount of chromium, about 20 mg/L, passes into the weakly concentrated H₂SO₄ solution, the degree of leaching is low and equal to 20.6%. When using 50% H₂SO₄, the highest degree of transition of Cr (94.8%) from ferrochrome slag to sulfuric acid occurs at a high temperature of 90 °C in 150-180 minutes. Deeper extraction of chromium cations into acid occurs at 80-90 °C. The maximum content of Cr³⁺ in the acid is achieved in 46-107 minutes and amounts to (0.33-0.68)%. Conclusions. It was revealed that with increasing process duration and increasing temperature, the degree of extraction increases. The maximum transition of chromium into acid from high-carbon ferrochrome slag occurs at a temperature of 76-90 °C and a process duration of 145-180 minutes. The degree of extraction reaches 97.9%. An increase in the temperature of the process of leaching chromium from VUVC with concentrated sulfuric acid initiates the extraction of chromium from the raw material.

CREATION OF A CHEMICAL CURRENT SOURCE USING REDOX REACTIONS IN THE "IODINE-IODIDE" SYSTEM

2024-04-22T11:24:56+05:00

Introduction. Chemical current sources play an important role in energy supply systems that are closely related to everyday life. The ever-increasing dependence on electricity creates a huge demand for appropriate energy storage devices. The purpose: The aim of the work is to create a chemical current source based on the use of the "red – ox" iodine-iodide system and to determine the patterns of formation of electromotive force (EMF) and short-circuit current (short-circuit current) in water solutions depending on the concentration of ions. Objects. The experiments are carried out by measuring the EMF formed between graphite electrodes and SCC. A special installation has been assembled, consisting of an electrolyzer with separated electrode spaces, an ammeter, a voltmeter and graphite electrodes. Solutions of iodine and potassium iodide served as the electrolyte. Results. In an electrolyzer, the electrode spaces of which are separated by an anionite membrane, when one of the spaces is filled with a solution of iodine and the other with potassium iodide, an EMF is formed between the graphite electrodes. Under optimal conditions, the EMF and SCC values will be higher than 135 mV and 10 mA, respectively. Conclusion. The possibility of forming a chemical current source using the "red – ox" iodine-iodide system is shown. The patterns of EMF and SCC formation and their changes depending on ion concentrations are revealed. The results of the study show that "red – ox" systems of alternating valent elements can be used to create flowing chemical current sources with increased electrical capacity

SCIENTIFIC SUBSTANTIATION OF THE MAXIMUM PERMISSIBLE CONCENTRATION OF OIL IN THE SOIL FOR THE TERRITORY OF THE INDUSTRIAL ZONE OF THE UZEN DEPOSIT IN THE MANGYSTAU REGION

2024-05-21T13:56:30+05:00

Introduction. The development and operation of an oil field is accompanied by an oil spill and the formation of oil-contaminated soils. The process of natural restoration of oil-contaminated soils is extremely slow. Therefore, among environmental protection measures, the rationing of oil content in soils is extremely important. The purpose of the work is to develop a standard for the maximum permissible concentration of oil in the soil for the industrial zone of the Uzen field.Methods. The basis for the development of the maximum permissible concentration of oil in the soils of the studied field is the "Methodological recommendations for the hygienic justification of the maximum permissible concentration of chemicals in the soil". The determination of the mass fraction of oil in the studied media was performed by gas-liquid chromatography. The chemical composition of the soil was determined by atomic absorption spectrometry. The determination of the specific activity of radionuclides was carried out by gamma-spectrometric method on the «MKS 01A Multirad» spectrometer. Results and discussion. During the work for the field, in accordance with the requirements for substantiating the maximum permissible concentration, an assessment was made on the physico-chemical and biological properties of soils and oils. Based on the experimental data obtained, the maximum permissible concentration of oil in the soil of the industrial zone of the Uzen field at the level of 3 g/kg is justified and reflects the real conditions in which oil intake in the soil will not cause harmful effects on human health and the environment.

THE BASE PRESENCE AT THE ALKYLSULFOCHLORINATION OF β-AMINOPROPIOAMIDOXIMES IN CHLOROFORM AND WATER

2024-04-16T14:38:09+05:00

Abstract. We have studied the regioselectivity of alkylsulfochlorination of β-(4-phenylpiperazin-1-yl)- and β-(benzimidazol-1-yl)-propioamidoximes using AlkSO₂Cl under two conditions: (i) in chloroform in the presence of tributylamine (Bu₃N) as a base at room temperature (r.t.); (ii) in water and acetone (4:1) without Bu₃N at r.t. The reaction under the conditions (i) leads to the return of the original amidoximes, the formation of 2-amino-8-phenyl-1,5,8-triazaspiro[4.5]dec-1-ene-5-ammonium chloride and β-(benzimidazole-1-yl)propioamidoxime hydrochloride. When alkylsulfochlorination occurs under conditions (ii): β-(4-phenylpiperazin-1-yl)propioamidoxime reacts with iso-propylsulfonyl chloride and β-(benzimidazol-1-yl)propioamidoxime ‒ with methylsulfonyl chloride, 2-amino-8-phenyl-1,5,8-triazaspiro[4.5]dec-1-ene-5-ammonium hydrochloride, iso-propylsulfonate and O-methylsulfonyl-β-(benzimidazol-1-yl)propioamidoxime hydrochloride were obtained in quantitative yields. Thus, under conditions (i) Bu₃N binds alkylsulfochlorides into alkylsulfonyltributylammonium chlorides and the alkylsulfochlorination products of β-aminopropioamidoximes were not formed; under conditions (ii) alkylsulfochlorination products were isolated: 2-amino-8-phenyl-1,5,8-triazaspiro[4.5]dec-1-ene-5-ammonium iso- hydrochloride, propylsulfonate and O-methylsulfonyl-β-(benzimidazole-1-yl)propioamidoxime hydrochloride.

OBTAINING HUMATE-, NITROGEN AND MOLYBDENUM-CONTAINING LIQUID ORGANOMINERAL FERTILIZERS

2024-06-04T08:50:02+05:00

Introduction. The presence of humic substances (HS) and microelements in liquid organomineral fertilizers (LOMF) makes it possible to balance the mineral nutrition of plants and thereby increase the agricultural crops yield. The use of such fertilizers significantly increases the efficiency and reduces the costs of using mineral fertilizers. The aim of this work is to study the patterns of new types LOMF obtaining process, including macro- and microelements and physiologically active humic substances, and its composition and properties. Methods. Chemical analysis, inductively coupled plasma atomic emission spectrometer, infrared spectroscopy. Results and discussion. The processes of synthesis of LOMF through the interaction of sodium humate and ammonium heptamolybdate tetrahydrate were studied. Analysis of obtained results showed the same nature of the composition dependence and properties of the obtained LOMF on time. It was found that increasing the time from 10 to 120 min leads to an increase in the yield of humic acids (HA^daf) to 40.08%, the N content to 4.62% and Mo to 0.17%, the amount of COOH to 1.80 mg-eq/g and OH_phen. groups – up to 0.71 mg-eq/g. It has been shown that with an increase in S:L ratio from 0.3:100 to 0.7:100, the HA^dafdecreases to 36.97%, and the N and Mo contents increase, respectively, to 6.0 and 0.37%. Conclusion. The regularities of the time influence and S:L ratios on the composition and properties of LOMF samples have been established. It has been shown that an increase in time and S:L ratio contributes to an increase in the content of N and Mo, the carboxyl and phenolic hydroxyl groups. The changes in these parameters have different effects on the HA^daf. The presence of HS, N, Mo, COOH and OHphen groups in the resulting products allows them to be used in agriculture and for restoring soil fertility.

SOFT MECHANOCHEMICAL SYNTHESIS OF ZINC, MANGANESE AND NICKEL DIPHOSPHATES

2024-04-12T14:15:26+05:00

Introduction. Currently, condensed phosphates are used in many growths, while crystalline phosphate polymers were previously obtained by thermolysis, which is economically and environmentally unprofitable. In this regard, obtaining the required product at relatively low temperatures by mild mechanochemical synthesis (MMhC) is one of the urgent tasks. The purpose of this work is to establish conditions for the soft mechanochemical synthesis of zinc, manganese and nickel diphosphates. To achieve the goal of the work, a new mechanothermal method for the production of diphosphates of a number of d-elements (Zn, Mn, Ni) was developed, consisting of two stages of synthesis: 1) in the mechanochemical process of diphosphate; 2) in the heat treatment of the intermediate product. The mechanochemical synthesis was carried out in grinding machines, at a modern RETSCH brand planetary mill. Also, various complexes of physico-chemical research methods were used to study the properties and composition of the obtained materials. Results and discussions. With mechanochemical activation of the studied mixtures, intermediate compounds - NH₄M(II)PO₄ can be obtained, and thermolysis at low temperatures – target products - individual diphosphates Zn, Mn, Ni (400°C, 300°C, 500°C.) It has been established that this method is environmentally friendly and low energy costs. Conclusion. Conditions for the soft mechanochemical synthesis of zinc, manganese and nickel diphosphates were established.

STABILIZING ADDITIVE FOR CRUSHED STONE-MASTIC ASPHALT CONCRETE BASED ON A LOW-GRADE PRODUCT AND WASTE FROM THE PRODUCTION OF CHRYSOTILE ASBESTOS

2024-04-24T13:50:41+05:00

Abstract: The results of a study of adsorption activity for bitumen and the physical and mechanical characteristics of the additive for crushed stone-mastic asphalt concrete (SMA), made on the basis of low-grade chrysotile and dusty waste from the enrichment of chrysotile-asbestos production, are presented. Structuring of the surface of layered magnesium silicates 3MgO 2SiO2 2H2O by treatment with dilute solutions of mineral acids is proposed, in which magnesium dissolution occurs only from the surface layers of magnesium silicate. At the same time, due to the structural features of the tubular structure - multilayering, the initially fibrous structure of magnesium hydrosilicate is preserved, and a layer enriched with silicon is formed on the surface of the fibers. As a result, the surface acquires a more amorphous state, which causes an increase in adsorption activity for bitumen. Based on the results of establishing the physical and mechanical characteristics of an additive made from low-grade chrysotile and powdered waste chrysotile-asbestos in the prepared crushed stone-mastic asphalt concrete mixture (ShchMAS-20), it is shown that the selected composition meets all the requirements of GOST 31015-2002 “Asphalt concrete mixtures and crushed stone asphalt concrete - mastic. Technical conditions".

MODIFICATION OF SODIUM HUMATE WITH ALUMINUM DIHYDROPHOSPHATE DEPENDING ON TIME AND THE RATIO OF SOLID AND LIQUID PHASES

2024-05-23T13:19:18+05:00

Abstract. Introduction. Due to their high chemical activity, humic compounds participate in various reactions. A large number of functional groups opens up wide possibilities for the humic compounds chemical modification. Most studies on the modification of humic substances are focused on studying the structure of humic substances, as well as on the factors influencing the completeness of the release of one humic substances fraction. The purpose of the work is to study the patterns of modification processes of sodium humate with aluminum dihydrogen phosphate, to determine the composition and properties of the resulting organomineral composite materials. Methods. Chemical analysis, infrared spectroscopy, X-ray analysis. Results and discussion. The composition and properties of organo-mineral composite materials obtained by conversion of sodium humate with aluminum dihydrogen phosphate have been determined. With an increase in the S:L ratio from 1:0.5 to 1:1.5, the yield of humic compounds increases from 15.62 to 21.92%, and the amount of phosphorus and nitrogen, on the contrary, the S:L=1:1.5 decreases, that is, the amount of phosphorus decreases from 37.51 to 32.19%, and the amount of nitrogen decreases from 1.78 to 1.11%. This is due to the improvement of diffusion conditions by reducing the medium viscosity and increasing the rate of primary components interaction. And the reduction in the amount of nitrogen occurs due to a decrease in ammonia consumption due to the humic substances neutralizing ability. Conclusion. It has been shown that the conversion of humic compounds with aluminum dihydrogen phosphate leads to a change in its composition and properties; the resulting products are enriched with phosphorus and nitrogen, and have good physicochemical and physicomechanical properties. After the macromolecules of humic compounds modification with aluminum dihydrogen phosphate, the number of oxygen-containing functional groups increases as a result of which the ion-exchange, complexing, sorption, detoxification and growth-stimulating properties is observed.

Keywords: sodium humate, aluminum dihydrogen phosphate, chemical modification, organomineral composite material, carboxyl and phenolic groups, complexation

SYNTHESIS AND STUDY OF THE INFLUENCE OF ALKALI CONCENTRATION AND TEMPERATURE ON THE PHYSICOCHEMICAL PROPERTIES OF CRYOGELS BASED ON GELATIN AND CHITOSAN

2024-06-19T16:06:55+05:00

Abstract. Introduction: Much of the polymer research is focused on improving existing polymers or developing new biomaterials with tunable properties. Natural polymers that have certain segments that contribute to an additional therapeutic effect are more often used as a biocompatible polymer. Polymers can be produced using a variety of methods, including covalent cross-linking, dynamic covalent cross-linking, physical cross-linking, cryopolymerization, 3D printing, electrospinning, etc. Cryopolymerization is a unique method and has several advantages over other methods. By cryofreezing it is possible to obtain a porous structure in which the size and volume of the pores can be controlled by changing the concentration of the initial monomers and temperature. The purpose of this study is to determine the effect of alkali concentration and cryopolymerization temperature on the properties of cryogels. The objects of study in this work are cryogels based on gelatin and chitosan. Methodology. The functional groups of the cryogels were determined by IR spectroscopy. The results of a study of the sorption and desorption of polymers are presented. The results of polymer degradation in phosphate-saline solution over 8 weeks are also shown. These studies were based on changes in mass, that is, they were carried out using the gravimetric method. Conclusion. The results of a study of the influence of alkali concentration and temperature on the physicochemical properties of cryogels based on gelatin and chitosan are presented. Cryogels based on gelatin and chitosan are synthesized without the use of harmful chemical cross-linking agents, which makes them attractive for tissue engineering.

CHARACTERISTICS OF MUTUAL ACTIVATION OF AN INTERGEL SYSTEM BASED ON HYDROGEL POLYMETHACRYL ACID AND POLY-4-VINYL PYRIDINE

2024-05-21T15:41:48+05:00

Abstract. Introduction. The electrochemical properties of mutual activation of polymer networks as a result of remote interaction in an intergel system have been studied. An intergel system consisting of hydrogels of rare crosslinked polymethacrylic acid (hPMAA) and poly-4-vinylpyridine (hP4VP) was chosen as the object of study [1,2]. The purpose of the work is to study the mutual activation features of the intergel system of rare crosslinked hPMAA: hP4VP. The obtained results as the contact time of hydrogels with water increased, zones of maximum and minimum conductivity were observed at the highest points of initial conductivity for different ratios of hPMAA:hP4VP hydrogel systems. In the 6:0 ratio of hPMAA hydrogel, the specific conductivity of the aqueous medium reached its maximum value after one day, and the pH value of the medium decreased relatively to about 4.95. The swelling degree of hPMAA hydrogel was constant at 6:0 different time intervals. In this system, only one polymer, namely hPMAA showed that the hydrogel's water absorption capacity was limited. In the 5:1 ratio of the intergel system, the specific conductivity of the medium reached a high value, and the pH value decreased in the 5:1 ratio. After 2.5 hours of study, a decrease in the conductivity of the aqueous medium was observed at 4:2 hydrogel ratio. After 6 hours, the highest degree of swelling was maintained at 1:5 ratio. In the presence of hP4VP hydrogel at a ratio of 0:6, the pH of the medium increased from 5 to a maximum value of 6.6 within 24 hours. Conclusion. The electrochemical properties of hPMAA:hP4VP hydrogel system were studied by remote interaction. Based on the systematic work, we synthesized the required acidic hydrogel hPMAA:hP4VP and carried out various studies on their properties. To create an intergel system, the obtained hydrogels in seven different proportions were made into an intergel system and their interactions were studied using various physicochemical methods. As a result of the study, the remote interaction of hydrogels in the intergel system leads to conformational changes in their intercellular bonds which undergo additional swelling. As a result of mutual activation, the hydrogels move to a highly ionized state.

INVESTIGATION OF SURFACE PROPERTIES OF MODIFIED BITUMEN COMPOSITIONS

2024-06-24T11:48:30+05:00

Introduction. One of the main reasons for premature destruction of road surfaces is the poor quality of road bitumen. An effective way to improve the quality of a bitumen binder is to modify it with polymer or surface-active additives. The goal is to determine the effect of the concentration of modifiers on surface tension in binary "bitumen-surfactant", "bitumen-polymer" and triple "bitumen-surfactant-polymer" systems. The methodology of the work included measuring the surface tension of modified bitumen systems depending on the quantitative content of additives in bitumen. Results and discussion: As follows from the analysis of the data obtained, in bitumen systems with a limited concentration of polymer AG-4I (C≤1 g/dm³), the effect of reducing surface energy at the interface with air is achieved by concentrating surfactants in the surface layer, which are part of the structure of the bitumen itself. The extreme nature of the change in surface tension was also recorded in AC-2 bitumen compositions. Conclusion: In the "bitumen-AG-4I-AS-2" triple systems, the change in the specific surface energy at the "liquid-gas" interface is not an additive value, taking into account the separate contribution of AG-4I and AS-2. The concentration threshold of additives to achieve a minimum surface tension varies in comparison with binary compositions. With the combined administration of AG-4I (C=1g/dm³) and AC-2 (C=1g/dm³), the surface tension decreased by 9.30 mN/m compared with unmodified bitumen.

INFLUENCE OF EXTERNAL FACTORS ON BINARY SYSTEMS DURING RAFT POLYMERIZATION

2024-06-26T09:02:09+05:00

The article discusses the method of radical copolymerization as an effective way to obtain new polymer compounds with practically valuable properties. This method is based on the free radical mechanism, in which the sequential addition of molecules of an unsaturated monomeric compound to a growing macroradical occurs. Due to the relative simplicity of this method, it makes it possible to produce a large number of polymers for various purposes on an industrial scale.

Unsaturated polyesters of various compositions and molecular weights, which can significantly affect the properties of the final products, are considered promising coreagents capable of entering into radical copolymerization reactions with vinyl monomers.

The article discusses the results of studies of polymer gels obtained on the basis of unsaturated carboxylic acids. The author refers to previous studies, showing that such gels have high sorption capacity, while the starting material does not have similar properties. The following describes the structure analysis of p-PGFPh copolymers with these acids, where important characteristics such as the presence of ionized units in vinyl monomers are discussed. The significance of these studies for the creation of materials with the necessary properties of sorption and interaction with other substances. Study of the influence of environmental pH on the behavior of copolymers based on polypropylene glycol fumarate phthalate with acrylic and methacrylic acids. The equilibrium degree of swelling of the studied copolymers in aqueous solutions at different temperatures was also determined by the gravimetric method. In general, analysis of the swelling curve when varying the acidity/alkalinity of the external solution indicates that the gels we synthesized are polyelectrolytes; analysis of the curve when exposed to temperature, the resulting copolymers are thermosensitive. Thus, the main idea of the article is the importance of using unsaturated carboxylic acids to create polymer gels with high sorption capacity and emphasizes the importance of analyzing the structure of such materials to understand their properties and application possibilities.