-
Date submitted2022-10-19
-
Date accepted2023-02-14
-
Date published2023-04-25
Electric steelmaking dust as a raw material for coagulant production
The paper describes the issues associated with waste generated during steel production and processing, in particular the dust from electric arc furnaces (EAF). An effective solution for the disposal of such waste is its involvement in processing to obtain valuable products. This paper studies the physical and chemical properties of EAF dust produced during the smelting of metallized pellets and captured by the dust and gas cleaning system of the steel-smelting shop at the Oskol Electrometallurgical Combine, Belgorod Region. The results obtained in the study of the chemical and disperse compositions of dust, the microstructure of the surface made it possible to propose the use of dust as a raw material for coagulant production. The conditions of acid-thermal treatment of dust are determined, contributing to the partial dissolution of iron (II), (III), and aluminium compounds, which ensure the coagulation processes during wastewater treatment. Model solutions show high efficiency (> 95 %) of water treatment from heavy metal ions by modified EAF dust.
-
Date submitted2020-10-22
-
Date accepted2021-03-02
-
Date published2021-04-26
Dynamic simulation of industrial-scale gibbsite crystallization circuit
- Authors:
- Vladimir O. Golubev
- Tatyana E. Litvinova
Population balance model is crucial for improving the method of aluminum hydroxide massive crystallization and enhancing the quality of control over industrial precipitation trains. This paper presents the updated population balance model, which can be used for simulation of industrial-scale precipitation. Processes of birth-and-spread and particle breakage are considered integral parts of the precipitation process along with secondary nucleation, growth and agglomeration of particles. The conceptual difference of the proposed system of equations is its ability to reproduce the oscillatory process that occurs in precipitation circuits as a result of cyclic changes in the quality of the seed surface. It is demonstrated that self-oscillations can occur in the system without any external influence. The updated model is adjusted and verified using historical industrial data. The simulation of seed-recycle precipitation circuit showed an exact correspondence between the calculated dynamic pattern of changes in particle size distribution of aluminum hydroxide and the actual data.
-
Date submitted2019-07-24
-
Date accepted2019-09-13
-
Date published2019-12-24
Integrated mining projects in underdeveloped territories of Russia: substantiation of implementation parameters
- Authors:
- T. V. Ponomarenko
- E. A. Khan-Tsai
- Ch. Bavuu
Complex mining projects, as a rule, have significant economic and social impact on the territory, sometimes entire regions where they are implemented. Consumers of their implementation effects are population, government, buyers, lenders and other stakeholders. Therefore, development of transport infrastructure in integrated projects for development of mineral deposits should have state support, forms of which are very diverse. In Russia parameters of concession agreements for construction of transport infrastructure, carried out in conjunction with projects for development of mineral deposits, are not regulated or justified. Aim of the work is to develop an organizational model and justify parameters of concession agreement for construction of the railway as a key element of transport infrastructure necessary for successful implementation of the project for development of a large coal deposit in a low-developed region. Research methods are: strategic, institutional, investment analysis, modeling and forecasting methods. The article proposes an approach to justification of technical, economic and financial parameters of concession agreement implemented during realization of an integrated mining project. As a result of the study, a concession agreement model was developed for construction of railway section as part of an integrated mining project, including development of a deposit and construction of a mining and concentrating company.
-
Date submitted2019-04-28
-
Date accepted2019-06-28
-
Date published2019-10-23
Determination of Optimal Fluorine Leaching Parameters from the Coal Part of the Waste Lining of Dismantled Electrolytic Cells for Aluminum Production
- Authors:
- N. V. Nemchinova
- A. A. Tyutrin
- V. V. Somov
When aluminum is obtained by electrolysis of cryolite-alumina melts when the baths are sent for capital repairs, a solid technogenic product is formed – waste lining of electrolytic cells (WLEC). The volume of formation of WLEC is 30-50 kg per 1 ton of aluminum. Currently, it is mainly stored at landfills near industrial enterprises, causing harm to the environment. However, this technogenic raw material contains valuable components (fluorine, aluminum, sodium) that can be extracted to produce fluoride salts, which are in demand during the electrolytic production of aluminum. The objects of research were samples of the coal part of the waste lining of dismantled S-8BM (E) type electrolytic cells of «RUSAL Krasnoyarsk» JSC (Krasnoyarsk) of RUSAL company. According to the X-ray experiment diffraction analysis (using a Bruker D8 ADVANCE diffractometer) of the phase composition of the samples, it was found that the main fluorine-containing compounds are cryolite, chiolite, sodium and calcium fluorides. The total fluorine content in the studied samples averaged 13.1 %. We conducted studies on the leaching of fluorine from WLEC with a solution of caustic alkali (NaOH concentration – 17.5 g/dm 3 ). The process was carried out in a mechanically agitated reactor using a BIOSAN MM-1000 top drive laboratory stirrer with a two-blade nozzle. By the method of mathematical planning of a three-factor experiment, the mutual influence of three leaching conditions on the optimization parameter was established – the extraction of fluorine in solution (in percent). The maximum recovery of fluorine from WLEC to the leach solution averaged 86.4 % and was achieved with the following indicators:processtemperature–95 ° C, the ratio ofliquidtosolidphase–9:1,duration– 210 min.
-
Date submitted2019-01-13
-
Date accepted2019-03-04
-
Date published2019-06-25
Thermodynamic model of ion-exchange process as exemplified by cerium sorption from multisalt solutions
A complex heterogeneous process of ion exchange can be defined with an isotherm-isobar equation of the chemical reaction, which describes differential affinity between the process and its effect – the law of mass action. Ion exchange includes processes accompanied by changes in the charge of ions and functional groups caused by the passing of ionic bond into covalent one. Hence isotherm equations of ion exchange for such processes must differ from conventional stoichiometric equations, but they can be obtained by classical study approaches to ion exchange equilibrium. The paper describes a new thermodynamic model, based on linearization of mass action law, modified for the ion exchange equation. The application of this model allows to define stoichiometry of ion exchange and the shape of ions adsorbed by the solid phase of ion-exchange resins, as well as to estimate equilibrium constant and Gibbs free energy of the process. Comparative analysis has been carried out for the thermodynamic model of cerium sorption in the form of anionic complex with Trilon B from a multisalt solution with ionic strength of 1 mol/kg (NaNO 3 ) under рН = 3 and temperature 298 K on a test sample of weak-base anion-exchange resin Cybber EV009. Experimental isotherm of the sorption has been obtained. Calculations of thermodynamic parameters have been performed using Langmuir, Freundlich, Dubinin – Radushkevich, Temkin and Flory – Huggins models, as well as thermodynamic model of linearized mass action law, proposed by the authors. Calculated values of the equilibrium constant and Gibbs energy – K = 9.0±0.5 and ΔrG 0 298 = –5.54±0.27 kJ/mol – characterize the sorption of EDTA cerate ions by ion-exchange resin. The shape of adsorbed ions has been defined in Stern-Helmholtz layer of CeTr, and total capacity of anion resin EV009 for EDTA cerate ions has been estimated as q ∞ = 2.0±0.1 mol/kg.
-
Date submitted2018-07-22
-
Date accepted2018-09-07
-
Date published2018-12-21
Game theory model of state in-vestment into territories of advanced development in the regions of mineral resources specialization
- Authors:
- A. V. Kozlov
- A. B. Teslya
- S. A. Chernogorskii
Historically developed and non-compliant with modern conditions, the structure of industry placement and related inequality in economic development of certain territories are additional negative factors that hinder economic development of the country. Hence, the search for new organizational forms and methods of territorial development, facilitation of industrial growth in regions with mineral resources specialization become more and more relevant. Another no less important issue is justification of economic feasibility of using such tools and assessment of critical consequences of their application. Suggested by the authors, game theory model of state investment into territories of advanced development describes the method of limited resources distribution and becomes an instrument to assess the feasibility of investment into creation of advanced development territories under the conditions of insufficient information and actions of specific interest groups. Application of the suggested game theory model of state investment into creation of advanced development territories allows to forecast behavior of program participants, to model consequences of management decisions both for government structures and separate program participants.
-
Date submitted2009-08-10
-
Date accepted2009-10-21
-
Date published2010-02-01
Precipitation of alumina liquor inclusive potassium
- Authors:
- V. V. Radko
The materials of experimental research on alumina liquor precipitation kinetics in system Na 2 O – K 2 O – Al 2 O 3 – H 2 O using carbonated alumina hydroxide as a seed are presented. Particle size distribution (PSD) analyses of settling products are given. Correlation link of alumina liquor decomposition degree and average median diameter of received aluminum hydroxide are shown.
-
Date submitted2009-08-27
-
Date accepted2009-10-25
-
Date published2010-02-01
Regularities of change of water-repellent properties of the nanostructured metal powders on the base of aluminium
Regularities of change of water-repellent properties of metal powders on the basis of aluminium depending on the program of nano-structural surface modifying are studyed. The rows of increase of water-repellent properties of modified aluminium on the base of coarse-dispersed and high-dispersed (PAP-2) powders are obtained. Several specimens excelling initial hydrohobic PAP-2 inits water-repellent capacity are found out. The research uses the methods of XP-, EDX- spectroscopy and gravimetry.