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Date submitted2024-05-08
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Date accepted2024-11-07
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Date published2024-12-12
The effect of mechanical and thermal treatment on the characteristics of saponite-containing material
Solving the problems of modern building materials science is reduced to obtaining high-quality materials, expanding and searching for a rational raw material base, which can be carried out through the use of various industrial wastes. In this paper, the possibility of using waste from the mining industry – saponite-containing material (SCM) obtained during the enrichment of kimberlite ores from the Lomonosov diamond deposit, as an active mineral additive for cement binders and concretes is considered. The influence of mechanical and thermal treatment on a number of properties of the material selected from the tailings dump and in its initial state was studied. The study of the surface activity of SCM samples consisted in determining the sorption capacity, acid-base centers and their distribution. An increase in the activity of the surface of the material particles as a result of mechanical activation and its decrease during temperature treatment were determined. These effects are associated with phase rearrangements and structural changes in the sandy-clay rock, which was confirmed during thermal analysis. The temperature effect has no pronounced effect on the microstructure, the “smoothness” of the particles and the formation of a consolidated surface of the structural elements of the saponite-containing material are noted.
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Date submitted2024-05-06
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Date accepted2024-06-14
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Date published2024-07-04
Natural carbon matrices based on brown coal, humic acids and humine extracted from it for purification of aqueous solutions from low molecular weight organic impurities
Heterogeneous systems including natural carbon matrices in the solid phase and aqueous solutions of low molecular weight organic compounds with positive and negative variations from ideality in the liquid phase are considered. The technical characterization of the considered supramolecular ensembles on the basis of brown coal of the Kara-Keche deposit (Kyrgyzstan), humic acids and humine extracted from it is given. Functional analysis of the samples was carried out using FTIR spectroscopy. The morphology of the surface of the considered carbon matrices has been investigated, in different points of which the local microelement composition has been established. An X-ray phase analysis of Kara-Keche brown coal and humic acids and humine extracted from it was carried out. The isothermal adsorption of bipolar molecules of glycine and urea, neutral D-glucose from aqueous solutions on solid carbon sorbents has been studied. An assumption has been made about the adsorption of low molecular weight organic compounds from aqueous solutions on humine and Kara-Keche coal in irregularities and pores of the carbon matrix of sorbents, for humic acids – on surface reaction centers. Due to its developed pore structure and resistance to acids and alkalis, humine from Kara-Keche coal is recommended for the purification of industrial wastewater from low molecular weight organic ecotoxicants.
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Date submitted2022-04-14
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Date accepted2022-07-21
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Date published2022-11-03
In-situ leaching of molybdenum and uranium by percarbonate and chloride-hypochlorite solutions
In-situ leaching of molybdenum and uranium is becoming an increasingly common process. The features of the material composition of ores, leading to a decrease in their filtration properties, were considered. Activation leaching with leaching solutions that have undergone electrophotochemical activation before contact with the ore mass were studied. Activation preparation of leaching solutions promotes the synthesis of clustered water molecules with collectivized protons and hydroxyl ions, as well as active forms of oxygen and hydrogen. Cell leaching of molybdenum from mature tailings of the Shakhtaminsk deposit was studied experimentally. After pre-oxidation with an active carbonate solution, a model borehole leaching was carried out with a chloride-hypochlorite solution. Molybdenum extraction on resin a was 85 % in 30 days. Experiments on the percolation leaching of uranium from the ores of the Uchkuduk and Sugraly deposits confirmed the potential possibility of a significant increase in the extraction of uranium by electrophotoactivated percarbonate solutions relative to aqueous solutions of sodium and ammonium carbonate. When leaching with carbonate solutions without an additional oxidizing agent, the extraction of uranium from the Sugraly deposit ore sample was 52 and 59 % (sodium carbonate and ammonium carbonate). The use of hydrogen peroxide as an oxidizing agent made it possible to achieve 87-88 % extraction into pregnant solutions in 21 days without pre-oxidation. The performed studies confirm the processing capability of extracting uranium and molybdenum by percolation leaching in columns and borehole leaching.
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Date submitted2019-07-09
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Date accepted2019-09-26
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Date published2020-04-24
Development of mathematical models to control the technological properties of cement slurries
Oil and gas producing enterprises are making increasingly high demands on well casing quality, including the actual process of injection and displacement of cement slurry, taking into account requirements for the annular cement level, eliminating possible hydraulic fracturing, with developing a hydraulic cementing program. It is necessary to prevent deep invasion of cement slurry filtrate into the formation to exclude bridging of productive layers. It is impossible to fulfill all these requirements at the same time without application of modifying additives; complex cement compositions are being developed and applied more often. Furthermore, need to adjust cement slurries recipes appears for almost every particular well. In order to select and justify cement slurries recipes and their prompt adjustment, taking into account requirements of well construction project, as well as geological and technical conditions for cementing casing strings, mathematical models of the main technological properties of cement slurries for cementing production casing strings in the Perm Region were developed. Analysis of the effect of polycarboxylic plasticizer (Pl) and a filtration reducer (fluid loss additive) based on hydroxyethyl cellulose (FR) on plastic viscosity (V), spreadability (S) and filtration (F) of cement slurries is conducted. Development of mathematical models is performed according to more than 90 measurements.
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Date submitted2018-09-02
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Date accepted2018-10-28
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Date published2019-02-22
Factors affecting bacterial and chemical processes of sulphide ores processing
- Authors:
- T. S. Khainasova
Extraction of valuable components from sulphide ores using microorganisms is a recognized biotechnological method, combining several advantages over traditional methods of mineral processing. This paper presents the main factors affecting the bacterial-chemical leaching and methods of leaching with the participation of microorganisms. Some physical-chemical (temperature, pH, oxygen, carbon dioxide, nutrients, metals and other chemical elements) and microbial (cell count and microflora activity) properties are given, either directly or indirectly (suppressing or contributing to the growth and oxidative capacity of microorganisms) affecting the kinetics of the process. The paper discusses the characteristics of the mineral substrate, including galvanic interaction of sulfide minerals and the formation of passivating layers on the surface of the ore during oxidation, emphasizing the importance of the electrochemical interaction of the components of the leaching system. Bioleaching is a complex process, which is a combination of mainly chemical reactions mediated by the microbial component, therefore, to improve the kinetics, it is necessary to consider, monitor and regulate the listed range of factors.
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Date submitted2018-01-19
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Date accepted2018-03-23
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Date published2018-06-22
Topochemical kinetics of external friction during mechanical and thermal activation of the friction contact
The article deals with the process of contact interaction (relative displacement) of surfaces as a chemical reaction, the regularity of which is described by the Arrhenius equation. The kinetic characteristics of Gersi-Striebeck are obtained taking into account the mechanical and temperature conditions of the frictional contact. The process of interaction of materials in friction in the form of regularities of topochemical kinetics, realized due to the processes of formation and growth of adhesion adhesion nuclei, makes it possible to present the experimental characteristics in the form of theoretical dependences. These dependences reflect the entire range of variation of the coefficient of friction from the speed of mutual movement of materials, including at ultra-low sliding speeds. In the framework of this approach, the lubricating action of the medium prevents and blocks the reactions of the transition of nuclei to actively growing nuclei.
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Date submitted2015-07-25
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Date accepted2015-09-01
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Date published2016-02-24
The phenomenon of isothermal transition of metastable aluminate solutions into the labile area and prospects of its industrial use
- Authors:
- V. N. Brichkin
- A. Kraslawski
The paper presents theoretically based requirements for the activation of synthetic gibbsite for maximum solubility of the activated product. The article describes the methodological foundations of gibbsite thermal activation and its effectiveness evaluation in terms of aluminate solutions decomposition. It is shown that to obtain high-saturation aluminate solutions, activation should provide generation of the reagent with highly-developed surface area, which is not identical to the structure of the deposited gibbsite. As a result of high-gradient thermal activation of synthetic gibbsite, it has been found that the targeted product develops predominantly an amorphous structure with a specific surface area up to 256 m2/ g, preserving its primary particle size. Activation products were investigated using modern methods of physical and chemical analysis. The experimental results confirmed the possibility of the activated product dissolution in the aluminate solution with a metastable compound and their spontaneous decomposition with aluminum hydroxide formation, characterized by high dispersion ability. It is shown, that a significant difference in kinetics and decomposition rates of solutions is connected with the use of a seed material with different particle size composition, which leads to the development of competing mechanisms, resulting in seed recrystallization, homogeneous and heterogeneous nucleation.
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Date submitted2015-07-07
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Date accepted2015-09-16
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Date published2016-02-24
Activation of heap leaching of low-sulfide ores the invisible gold
- Authors:
- A. G. Sekisov
- Yu. I. Rubtsov
- A. Yu. Lavrov
This article deals with a physical-chemical model of heap leaching processes justifying new technological approaches to recovering dispersed forms of gold from ores, placer sands and deute-rogene mineral raw materials. The key process of this model includes lattice diffusion of high-energy hydrion minerals and hydroxyl-radicals formed as a result of photochemical and electro-chemical processing of initial reagent aqueous solutions. Active components of gas-water emulsions obtained while processing initial reagent solutions provide a structural and material trans-formation of a mineral lattice which concentrates clusters of dispersed gold creating conditions for its interacting with complexing compounds of process solutions. The article also considers the technological processes of activation heap leaching of dispersed gold from the Pogromnoe ore field and the results of the experiments conducted in percolators with their charge ranged from 3 to 100 kg. The results have proved the efficiency of using gas-water suspensions prepared in the pho-toelectrochemical reactor with active ion-radical oxidizing agents.
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Date submitted2014-11-01
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Date accepted2015-01-02
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Date published2015-10-26
Development of an environmentally safe gold extraction method from refractory ores using sodium thiosulfate as an extractant
- Authors:
- Yu. V. Sharikov
- Ilkka Turunen
The article presents the results of a mathematical model development for the process of gold leaching from gold-containing ores and concentrates. A mathematical model has been developed by analyzing the chemistry of reactions and mass transfer processes. On the base of a kinetic extraction model and a hydrodynamic complete mixing model a mathematical model of thiosulfate leaching process in various types batch reactors, complete mixing flow process vessels and complete mixing reactor columns with different numbers of vessels in a column has been developed. The effect of the number of reactors in a column has been investigated and optimal segmentation conditions have been found. Based on the investigation of the process using the mathematical model a control system structure has been designed to provide maximum conversion at the exit area of a reactor column.
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Date submitted2009-07-05
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Date accepted2009-09-25
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Date published2010-04-22
Active methods for control of geomechanical state of rock mass in coal deposit mining under complicated geological-and-mining conditions
- Authors:
- F. N. Voskoboev
- Yu. A. Semenov
- V. A. Zvezdkin
The paper presents the main technologies, characteristics, schematic diagrams and parameters of active methods for control of geomechanical state of technogenic rock mass, domain and technical-and-economical efficiency of their industrial application.