ASSESSMENT OF IRON ORE CONCENTRATION CHARACTERISTICS ON THE BASIS OF ULTRASONIC MEASUREMENTS

A great number of various factors to a different extent impact iron ore treatment, properties of mineral composition of ore and parameters of technological equipment being some of them. To solve the problem of improving performance of a concentration plant in terms of the concentrate, it is required to elaborate effective scheduled procedures, upgrade technological equipment, develop methods of control over concentration processes considering technological properties of ore fed. There is suggested a method of improving efficiency of magnetic concentration of iron ore under the action of high-intensity ultrasound. There are established dependencies between physical-mechanical and chemical-mineralogical characteristics of iron ore slurry solids and their behavior in technological flows under controlled ultrasonic vibrations, this enabling simulation modelling of the process and specification of optimal controlling actions. The research object is assessment of characteristics and control of iron ore magnetic concentration on the technological line of the ore concentration plant. The research subject is the cyber-physical system based on using impacts of highintensity ultrasound on slurry solids to assess characteristics of iron ore magnetic concentration. Obtained dependencies and mathematical models of the non-linear spatial process of high-intensity ultrasound propagation in the iron ore slurry enable implementing the method of assessing characteristics of iron ore magnetic concentration and due to this increase efficiency of the mentioned operations. There are suggested methods of calculating intensity of high-intensity ultrasound in a certain point of the measurement area in order to perform forecast displacement of ground ore particles and changes of the fraction composition of slurry solids under the controlled action of high-intensity ultrasonic vibrations. The developed method and the software-engineering complex for its implementation enable restoring a function of distributing ground ore particles by sizes, forecasting results of technological operations and forming controlling actions.

On the Origin of the Magnetic Concentration Gradient Force and Its Interaction Mechanisms with Mass Transfer in Paramagnetic Electrolytes

The objective of this work is to analyze the origin of the magnetic concentration gradient force. The force will be studied in a diffusion system where a paramagnetic electrolyte diffuses through a thin, inert membrane under the influence of a homogeneous magnetic field. The force will be analyzed using the theory of magnetic circuits, i.e., by the concept of minimum reluctance principles. In addition, based on some previous studies, it will be discussed whether the minimum reluctance principle can be applied to mass transfer into and out of the diffusion layer at electrode/electrolyte interfaces. The results show that the magnetic concentration gradient force arises as a consequence of the minimum reluctance principle. Applied to the diffusion system, the magnetic concentration gradient force arises in the membrane as a consequence of the concentration gradient and hence, the reluctance gradient. The force acts on the flow in such a way that the reluctance in the membrane is minimized. The force implies two interaction mechanisms: attraction of the paramagnetic electrolyte flowing into the membrane in order to decrease the reluctance, and hindrance of the paramagnetic electrolyte flowing out of the membrane in order to hinder an increase in the reluctance. Based on previous studies, it is shown that the minimum reluctance principle can be applied to mass transfer into or out of the diffusion layer at electrode/electrolyte interfaces as well.

Comparative study on concentration properties of iron deposits (Mongolia)

Research aims to compare magnetic flotation results of iron deposits of Mongolia in order to obtain iron concentrate with low sulfur content that meets the standard of raw materials for metallurgical production. Research methodology. Representative samples were taken from Tumurtei deposit in Khuder soum (Selenge province), Tumur Tolgoi deposit (Darkhan-Uul province) and Chandmani Uul deposit (Dornogobi province). Iron grade in the primary ore from Tumurtei deposit was 42.03%, in Tumurtolgoi ore – 46.57% and in Chandmani-Uul ore–43.59%. The ore was crushed into 1 mm size through java crusher and gyratory crusher for the first stage. Dry magnetic concentration was conducted on the ore samples using Boxmag Rapid LR-1.4 Induced Magnetic Separator (the UK). The test work was conducted under the condition when the distance between gyrator of separator and rotation speed are constant and by this time magnetic strength was changed. At the next stage the concentrate of dry magnetic concentration was processed by wet magnetic separation. In order to reduce the sulfur content in the ore from Tumur tolgoi and Tumurtei deposits, flotation experiments were also conducted using UK Denver flotation machine. Ore and concentrator grade were determined using traditional titer method and X-ray fluorescence spectrometer (XRF), the mineral contents was analyzed by X-ray powder diffraction (XRD), elements in product of wet magnetic separator and final concentrate were analyzed using SEM-EDX, the thermal-gravy meter analysis was conducted using instrument TG/DTA7300. Results. Wet magnetic concentration of dry magnetic separation concentrates of all the studied ore allow obtaining concentrates with the high content of iron – from 64% to 66%. Flotation of the concentrate of wet magnetic concentration made it possible to reach iron content in Tumurtei and Tumurtolgoi deposits of 69.02% and 62.86% correspondingly and reduce Sulphur content to 0.2%, 0.48% correspondingly. This study covers the field of flotation technology to extract products with lower sulfur content which meet standard of modern metallurgical industry.