DEVELOPMENT OF A MODEL OF THE IRON ORE CONCENTRATE DEWATERING PROCESS

Исследование направлено на разработку адаптивной системы автоматического управления процессом обезвоживания железорудного концентрата, от протекания которого зависит производительность передела, качество и себестоимость выходного продукта данного процесса и дальнейших переделов. The research is aimed at developing an adaptive system for automatic control of the iron ore concentrate dewatering process, on the course of which the processing productivity, quality and cost of the output product of this process and further processing depends.

Study of iron content in iron ore concentrate increasing effect on sintering process indices and on metallurgical properties of sinter

Effectiveness of blast furnaces operation in many respects depends on metallurgical properties of agglomerate, in particular, iron content in the sinter and its basicity. At the same time, it is accepted that usage of iron ore concentrates with iron content more than 66–67% for sinter production results in decreasing of its strength. As a result of the planned modernization of the technological sections of the concentration plant JSC “Stoilensky GOK”, iron content in the concentrate will be increased to 68–70%. It makes it actual to accomplish comprehensive studies of metallurgical properties of the sinter while increasing iron content in the raw material. Results of the study of sinter properties presented, the sinter being obtained with utilization of iron concentrate with iron content 66.6 % (base), 68.0 and 69.2 % (exp. 1 and exp. 2 correspondently). The iron ore mixture for all the stages was the same and consisted of iron ore concentrate – 78.3%, sintering ore – 8.0%, lime – 5.5% and sintering additives (sludge, dust, scale) – 8.2%. The sintering mixtures composition for all the study stages differed only by fluxes and iron ore mixture consumption. 18 test sintering operations at three values of basicity 1.6, 1.8 and 2.0 units were accomplished. It was established that increase of iron content in the concentrate and basicity of the sinter results in improving of the sintering process indices, increase of the vertical sintering rate, sintering machines productivity, recovery and the sinter cold strength. Increase of the sinter basicity and its production with increased content of iron results in improving RDI indices at low temperature reducing. Results of the study of porosity indices and metallurgical properties of the sinter presented, in particular the collapsibility during reducing and temperature interval softening-melting presented. The advisability of concentrate with increased iron content utilization in the iron ore mixture shown.

SUBSTANTIATION OF APPLICATION FEATURES OF LIQUID MIXTURES FOR SCREENING OF ELECTROMAGNETIC FIELDS

The protective and rheological properties of composite materials based on water-dispersed paint and iron ore concentrate were studied. Features of liquid mixtures application for shielding of magnetic field of industrial frequency and electromagnetic field of ultrahigh frequency were substantiated. The study of the protective characteristics and rheological properties of composite materials based on water-dispersed paint and iron ore concentrate indicates the possibility of their use for shielding electromagnetic fields of a wide frequency range. It was found that the efficiency of the composite material (total shielding coefficient and reflection coefficient of electromagnetic waves) depends on the dispersion of the shielding filler, so the particle size analysis of iron ore concentrate was performed. The analysis shows that the predominant size of iron-containing particles is 23‒24 μm, which is quite acceptable for their uniform distribution in the body of the matrix. Shielding protective material was made of water-dispersion paint with the addition of iron ore concentrate in weight quantities of 15, 30, 45, 60%. The shielding coefficients of the electromagnetic field of industrial frequency and ultrahigh frequency with different filler content were measured. It was found that if the concentration of filler exceeds 30%, both the rheological characteristics of the mixture and the shielding coefficients of electromagnetic fields are unsatisfactory. A dramatic increase in shielding coefficients occurs at a filler concentration of 40%. This mixture has acceptable adhesive properties. It was established that the shielding coefficients could be enhanced if the dispersion of the filler is increased, which will contribute to the stability of the colloidal mixture and improve the rheological properties.

Design of liquid composite materials for shielding electromagnetic fields

This paper reports the principles of design and the examined protective properties of liquid materials for shielding the electric, magnetic, and electromagnetic fields over a wide frequency range. The materials were made on the basis of iron ore concentrate and a pigment additive, with water-dispersed and geopolymer paints used as a matrix. The tests of protective properties for the electrical and magnetic components of the electromagnetic field of industrial frequency showed that the electric field shielding coefficients at a concentration of the screening substance of 15−60 % (by weight) equaled 1.1−8.6; magnetic field – 1.2−5.3. The shielding coefficients of the material based on a water-dispersed paint are lower than those of a geopolymer one, which can be explained by the oxidation of an iron-containing component and a decrease in electrical conductivity. The shielding coefficients of the electromagnetic field with a frequency of 2.45 GHz are 1.2−7.9. The highest coefficients are inherent in the material with filler made of iron ore concentrate and titanium-containing pigment powder in a ratio of 1:1. To design materials with the required (predictable) protective properties, the relative magnetic, dielectric permeability of materials was calculated. It is shown that the obtained data are acceptably the same as the results from direct measurements of magnetic and dielectric permeability and could be used to calculate the wave resistance of the material and the predicted reflection coefficient of electromagnetic waves. Thus, there is reason to assert the need to build a database on the frequency dependence of effective magnetic and dielectric permeability in order to automate the design processes of composite materials with predefined protective properties.

Thermodynamic study of oxide phase compositions at reducing iron ore coosit by coals of Karazhyra deposit

Application of coals as reducing agents in the direct iron reducing process is a perspective way. For solid-phase iron reducing from iron ore concentrate of Bapy deposit, Republic of Kazakhstan, application of coals of Karazhyra deposit was proposed. Chemical composition of iron ore concentrate of Bapy deposit is presented. By application of methods and means of thermodynamic simulation, analysis of oxide phase composition was carried out. As a result of thermodynamic studies, it was revealed that at reducing of concentrate of specified composition, iron and aluminum oxides, magnesium, calcium, barium, and alkaline metals silicates, sulfides and phosphor compounds are presented in the oxide phase. A dependence of oxide phase parameters on temperature and coal rate was established. It was shown that a number of aluminum oxide, titanium and barium compounds and calcium and magnesium silicates is not practically varying within the whole temperature interval. The number of compounds, containing phosphor, potassium, natrium is decreasing while temperature is increasing due to elements transferring in gas phase. The number of sulfides is decreasing with temperature increase till the whole disappearance in the condensed phase. The number of iron oxides at the temperature higher 872K depends only on reducing agent rate. The number of oxide phase at the temperature lower 853K is maximum, then begins to decrease while the temperature is increasing, the reducing processes are developing and at the temperature of 1013K after completion of reducing process it reaches its maximum value which is not changing then up to temperature 1773K. The studies carried out enable to evaluate slag properties at elaboration of resource-saving technologies of iron direct reducing and can be used at forecasting and evaluation of metallization processes and the further re-melting of materials obtained from Bapy deposit iron ore concentrate of and Karazhyra deposit coals.