-
Date submitted2024-04-09
-
Date accepted2024-06-03
-
Date published2024-07-04
Analysis of the geochemical barriers effectiveness as the basis for the use of nature-like water purification technologies
Nature-like technologies are being introduced into many human activities including mining wastewater treatment. This work is based on long-term studies of the Sibay copper-zinc-pyrite deposit development. It is dedicated to assessment of geochemical barriers effectiveness in Cu, Zn, Cd removal from water of the Karagayly River (receiving quarry and dump drainage water). The research is based on the elements’ content and forms in water and bottom sediments, pH values etc. Four types of hydrogeochemical environment (formed due to changes in the water use over the past 20 years) were distinguished using discriminant analysis. The mechanisms of barriers formation and destruction were described. Statistical modeling of the metals’ precipitation was performed by multivariate regression analysis. Cu is adsorbed by recently formed Fe hydroxides, and, to a lesser extent, precipitates with sulfates as water pH increases. Antagonism to Mn hydroxides has been demonstrated, due to different physicochemical conditions for their precipitation. Zn enters solid phase mainly with sulfates, this element also forms its own mineral phases. The second mechanism is adsorption by recently formed Mn hydroxides, which corresponds to the idea of similar conditions for the precipitation of metal hydroxides. Cd behavior reflects conditions intermediate between these of Cu and Zn. Contribution of both mechanisms (related to Fe hydroxides and aqueous sulfates) is equal. Antagonism to Mn is absent. According to the assessment results using of nature-like technologies in situ in watercourses, canals and other water drainage systems is promising. Developed statistical models can be used for needs of experimental studies and artificial geochemical barriers engineering.
-
Date submitted2023-04-11
-
Date accepted2023-10-25
-
Date published2024-07-04
Acid mine water treatment using neutralizer with adsorbent material
One of the biggest issues in the mining sector is due to acid mine drainage, especially in those abandoned mining operations and active ones that fail to adequately control the quality of their water discharge. The removal degree of copper, iron, lead, and zinc dissolved metals in acid mine drainage was investigated by applying different proportions of mixtures based on neutralizing reagent hydrated lime at 67 % calcium oxide (CaO), with adsorbent material – natural sodium bentonite, compared to the application of neutralizing reagent without mixing, commonly used in the neutralization of acid mining drainage. The obtained results show that the removal degree of dissolved metals in acid mine drainage when treated with a mixture of neutralizing reagent and adsorbent material in a certain proportion, reaches discharge quality, complying with the environmental standard (Maximum Permissible Limit), at a lower pH than when neutralizing material is applied without mixing, registering a net decrease in the consumption unit of neutralizing agent express on 1 kg/m3 of acid mine drainage. Furthermore, the sludge produced in the treatment with a mixture of the neutralizing reagent with adsorbent material has better characteristics than common sludge without bentonite, since it is more suitable for use as cover material, reducing the surface infiltration degree of water into the applied deposit.
-
Date submitted2023-01-12
-
Date accepted2023-06-20
-
Date published2023-07-19
Improvement of energy efficiency of ore-thermal furnaces in smelting of alumosilicic raw materials
The issues of energy saving in pyrometallurgical production during processing of mineral raw materials in ore-thermal furnaces are particularly important for the development of new energy-efficient technologies. The reduction of the specific power consumption during melting at different stages of heating and melting of charge materials when modeling is related to obtaining kinetic curves in the process of kyanite concentrate regeneration in polythermal conditions. Based on practical data of carbo-thermal reduction the mathematical modeling of reduction processes from alumosilicic raw materials – kyanite was carried out. In this work, the nonisothermal method based on a constant rate of charge heating (i.e. a linear dependence between time and temperature) was used for the reduction of kyanite charge, which saves electrical energy. The experiments were carried out on a high-temperature unit with a heater placed in a carbon-graphite crucible. Based on the obtained kinetic dependences of nonisothermal heating of enriched kyanite concentrates in plasma heating conditions we obtained a number of kinetic anamorphoses of the linear form which point to the possibility of describing the reaction rate using the modified Kolmogorov – Erofeev equation for given heating conditions and within a narrow temperature range. The complex of mathematical modeling makes it possible to create a control algorithm of technological process of reduction of kyanite concentrate to a metallized state within the specified temperature range for the full flow of reaction exchange and to reduce the specific power consumption by 15-20 %. With the help of the received kinetic dependences, taking into account the thermodynamics of processes and current state of the art it is possible to create a universal thermal unit for the optimal carbothermal reduction of charge to a metallized state (alloy) with minimum power inputs compared to existing technologies.
-
Date submitted2021-03-31
-
Date accepted2022-04-26
-
Date published2022-11-03
Features of obtaining metallurgical products in the solid-state hydride synthesis conditions
- Authors:
- Andrey G. Syrkov
- Lyudmila A. Yachmenova
A scientific substantiation of solid-phase feedstock choice and preparation has been carried out, and the thermodynamic and kinetic aspects of solid-state hydride synthesis (SHS) of metal products have been analyzed using the nickel dichloride reduction as an example. The preliminary dehydration modes and methods for controlling the complete removal of crystalline water from chloride raw materials and Olenegorsk superconcentrate, which is natural oxide raw material, are described. Conditions, including initial solid chloride particle sizes, are established under which diffusion complications of reduction to metal in methyldichlorosilane vapor are minimized. Thermodynamic estimates of nickel chlorides and oxides reduction possibility, iron and copper with ammonia and methane at temperatures of 400-1000 K in equilibrium conditions have been carried out. It has been shown that the stoichiometric coefficients of the nickel dichloride in ammonia overall reduction reaction calculated by thermodynamic modeling are in agreement with experimental data. In contrast to the copper dichloride reduction, for nickel dichloride the formation of metal monochloride at the intermediate stage is uncharacteristic, which is associated with a higher thermal stability of nickel dichloride. The main kinetic regularities of the reduction of nickel, copper, and iron to metal under SHS conditions in ammonia, monosilane, and methane, as well as the nickel dichloride with methyldichlorosilane vapor and methane successive reduction, are considered. Approximation of experimental data by topochemical equations in a linear form showed that for reduction degrees a up to 0.7-0.8, these data are satisfactorily described by the Roginsky – Schultz equation. For a > 0,8 the “shrinking sphere” model works better, which confirms the localization of the solid-state reduction reaction at the interface, moves deep into the crystal with the formation of a of interlocked metal germs. The importance and prospects of the results obtained for the theory development of metallurgical processes, deep complex processing of natural iron oxide raw materials, metal products and new generation materials production, including superhydrophobic ones, are discussed. The relevance of the study from the point of view of applying the method of physical and chemical analysis to the study of complex heterogeneous metallurgical processes is noted.
-
Date submitted2022-04-12
-
Date accepted2022-05-25
-
Date published2022-07-26
Rare minerals of noble metals in the collection of the Mining Museum: new data
Modern analytical methods (optical and electron microscopy, X-ray microanalysis) were used to study the unique samples of sulfide ores from the Norilsk ore field from the Mining Museum collections of Saint Petersburg Mining University. Samples containing rare minerals of silver and platinum-group metals (sobolevskite, urvantsevite, sperrylite, argentopentlandite, froodite, kotulskite, and others) were studied. The chemical composition, grain sizes, aggregates, and mineral associations of more than ten noble metal minerals have been refined. The efficiency of combining various methods of electron microscopy and X-ray microanalysis for studying samples of this type is shown. The results of the work made it possible to obtain high-quality images of rare minerals, to detail information on museum objects, and to compile their scientific description. The conducted research showed the relevance of studying museum objects from known deposits of complex genesis and mineral composition in order to find and describe the samples with rare minerals.
-
Date submitted2020-06-29
-
Date accepted2021-05-21
-
Date published2021-09-20
Transformation of grains of technological raw materials in the process of obtaining fine powders
Crushing and grinding of materials are the most common processes of sample preparation for subsequent analysis and industrial application. Recently, grinding has become one of the most popular methods for producing nano-sized powders. This study investigates certain features of grain transformation in the process of grinding ores with finely dispersed valuable components in order to liberate them, as well as specifics of grinding metallurgical raw materials, metals and their mixtures for using them as initial components in metallurgical and other technological processes. We identified and examined structural and morphological changes of various powders after ultrafine grinding using the methods of scanning electron microscopy and X-ray microanalysis. It was proved that in order to take into account sample preparation artifacts during analytic studies of solid samples and development of technological processes, fine grinding of heterogeneous materials, especially if they contain metals, requires monitoring of the ground product by methods of scanning electron microscopy and X-ray microanalysis.
-
Date submitted2020-05-13
-
Date accepted2020-11-12
-
Date published2020-12-29
Improving the efficiency of terrigenous oil-saturated reservoir development by the system of oriented selective slotted channels
A comparative assessment of variation in the flow rate of oil production wells was performed taking into account increasing of perforated area of the productive part of the rocks, as well as recover of reservoir rocks permeability due to their unloading by creating slotted channels with the method of oriented slotted hydro-sandblast perforation. Different orientation directions and slotting intervals were analyzed, taking into account water encroachment of individual interlayers and azimuth direction of the majority of remaining reserves in separate blocks of the examined formation. In order to estimate development efficiency of terrigenous oil-saturated porous-type reservoirs by means of oriented slotted hydro-sandblast perforation, calculations were performed on a full-scale geological and hydrodynamic model of an oil field in the Perm Region. The object of modeling was a Visean terrigenous productive forma tion. The modeling of implementing oriented slotted hydro-sandblast perforation was carried out on a 3D filtration model for fourteen marginal wells, located in the zone with excessive density of remaining recoverable reserves and he terogeneous reserve recovery along the section. An optimal layout of slotted channels along the depth of the productive part of the well section was developed. Selective formation of 24 slotted channels was carried out con sidering the intervals of increased oil saturation. Comparative analysis of estimated flow rate of the wells was per formed for cumulative perforation of the examined productive formation and the developed method of slotted perforation. As a result of modeling, an increase in the oil average flow rate of 2.25 t/day was obtained. With oriented slotted hydro-sandblast perforation, incremental cumulative production for two years of prediction calculations per one well reached 0.5 thousand t.
-
Date submitted2019-05-02
-
Date accepted2019-07-09
-
Date published2019-10-23
Effect of Temperature on Solid-state Hydride Metal Synthesis According to Thermodynamic Modeling
Thermodynamic modeling of the reduction of copper dichloride in the media of various gaseous hydrides (ammonia, monosilane, methane) in the temperature range 273-1000 K was carried out. Calculations show that in narrower temperature ranges corresponding to the reactions of solid-state hydride synthesis (SHS) of metal sub- stances metal formation is usually supported by theoretical propositions. As a result of thermodynamic modeling, a principal result was obtained on the suppression of competing processes of nitriding, siliconizing and carbonization of metal under SHS conditions, which is important for metallurgical production. This additionally substantiates the correctness of previous experimental studies of SHS metals with modified surface and improved properties. By mod- eling, it was found that the reduction of solid copper dichloride to metal in ammonia or methane occurs stepwise (se- quentially, according to the Baykov rule) through the intermediate stages of the formation of a compound of low- valent copper – copper (I)chloride.
-
Date submitted2019-01-10
-
Date accepted2019-03-02
-
Date published2019-06-25
Modeling of the welding process of flat sheet parts by an explosion
- Authors:
- M. A. Marinin
- S. V. Khokhlov
- V. A. Isheyskiy
The list of materials subject to explosive welding is very extensive and amounts to several hundred combinations of various alloys and metals, and the variety of explosive welding schemes has more than a thousand options. In almost all technical solutions, the process involves the sequential creation of physical contact of the materials to be welded and their connection due to plastic deformation of the contacting surfaces. The strength of such a connection depends on the mode of the welding process. With the correct selection of the parameters of the mode, it is possible to obtain a high-quality connection of the required strength. However, the experimental selection of such options is a very laborious and costly process. Computer simulation and application of mathematical models for solving dynamic problems of explosion mechanics simplifies the search for optimal parameters and allows to predict the expected result in the shortest possible time. The article discusses the issues of modeling of explosive welding of metals, calculations related to the parameters of the process of formation of the weld using the Ansys Autodyn software package. A model is presented for analyzing the deformation process of explosion welding of a plate and its connection with a matrix. The main parameters of explosion welding (velocity, pressure, time) are determined. The adequacy of the obtained values was evaluated in the systems aluminum – copper and copper – steel. It also provides a comparative analysis of simulation results and field experiments. Based on numerical calculations, a conclusion was substantiated on the suitability of the model obtained for a preliminary analysis of the main welding parameters at the preparatory stage.
-
Date submitted2018-01-14
-
Date accepted2018-03-08
-
Date published2018-06-22
Development of research of low-dimension metal-containing systems from P.P. Weymarn to our days
- Authors:
- I. V. Pleskunov
- A. G. Syrkov
The article analyzes main laws discovered by P.P.Weymarn (1879-1935) during his work at the Saint-Petersburg Mining University, they are connected with obtaining metal-containing disperse substances with nanometer particle size. It enlists priority papers in this field (1906-1915) and describes peculiarities of P.P.Weymarn scientific school which has several connections to modern research being conducted at the Saint-Petersburg Mining University in the field of «nanotechnology» as well as by foreign scientists. The paper reveals continuity in the field of several objects (disperse metals) and the methodology of studying the properties and stoichiometry of substances depending on dispersity. It provides information on achievements in synthesis of surface nanostructured metals and low-dimension forms of substances in various porous matrixes. Among the studies of the XXI century developing Weymarn’s ideas there can be noted solid-state hydride synthesis of metals, layering of different-sized molecules of ammonium compounds on metals (Al, Cu, Ni, Fe), as well as synthesis of metal nanostructures (Ag, Cu, Bi) using porous glass as a particle size stabilizing matrix. In the latter case, the dispersity of the metal increases while its melting point decreases.
-
Date submitted2015-10-25
-
Date accepted2015-12-04
-
Date published2016-08-22
Regularities of selenium and chromium behavior in redox processes during hydrometallurgic treatment of solid phase products of rhenium extraction
- Authors:
- G. V. Petrov
- M. I. Kalashnikova
- S. B. Fokina
The main source of selenium is copper anode slime. But during the pyrometallurgical treatment of sulphide polymetallic ores significant amount of selenium along with radiogenic osmium and rhenium is concentrated in the solid-phase products of acid wash extraction and cannot be extracted, as gets lost with discharged chromium-containing solutions of osmium stage. The paper presents results of research into selenium reduction in the chromium-containing sulfuric acid medium by sulfurous gas and sodium sulphite. The use of the above reducers in optimum conditions leads to almost complete recovery of selenium (VI) while selenium (IV) extraction rate is not exceeding 60 %. The chrome (III) present in solutions has no impact on the selenium extraction rate. Chrome (VI) is almost completely reduced to a trivalent state, thus its negative impact on subsequent rhenium sorption from solutions purified from selenium is excluded. In view of a high rate of selenium extraction from chromium-containing sulfuric acid solutions formed in the process of radiogenic osmium production using sulfurous gas and sodium sulphite, choice of a method for selenium reduction is to a great extent dependent on the company’s profile.
-
Date submitted2014-12-20
-
Date accepted2015-02-05
-
Date published2015-12-25
Synergetic changes of tribochemical properties in the heterogeneous systems containing surface modified metals
- Authors:
- A. G. Syrkov
In the article tribochemical properties and synergetic effects in lubricants with metal addi-tives, characterized by surface modifcations, have been analysed. The priority results of measur-ings friction coefficient (f) and friction force (F fr) are given for heterogeneous systems in the form of И-20 oil with solid Al-additives, contatiing dispersed aluminium, with surface-modified triamon (Т), alkamon (A) and ethylhydridsiloxane according to various programs. It has been educed that with all other things being equal, triamon underlayers introduction into Al-additives with the external chemisorpted ethylhydridsiloxane layer results in the decrease of F fr and f in the system in proportion to the Т-underlayer number reduction from three to one. It has been discovered that the use of low-molecular Т-underlayer in Al-additives is a delicate method of summand value regulation (from 10,8 to 13,2 Н), accountable for intermolecular forces in the boundary fritction equation in the tribological pair applied.
-
Date submitted2009-09-22
-
Date accepted2009-11-17
-
Date published2010-06-25
Linear ccd-sensors based multiprocessor photometer system for spectral analysis
- Authors:
- A. S. Mustafaev
- A. B. Tsyganov
- B. V. Dobrolezh
There is presented a multiprocessor photometric CCD-system for a wide range of spectrometers and for various spectral analysis methods implementation.