The results of experimental power engineering examination of operating roasting conveyor machines are presented. These machines are used for complicated energy-intensive chemical-metallurgical process of roasting of iron ore raw materials in moving dense layer with cross feed of heat-carrying gas. The studies were conducted within the temperature ranges of thermal and aerodynamic operating conditions of the existing roasting conveyor machines. The causes of insufficient power engineering efficiency of the chemical-metallurgical roasting process were revealed, qualitative analysis of thermal conditions of roasting dense layer of iron ore raw materials was carried out. The data on temperature distribution of heating gas and iron ore material in different areas of a dynamic dense layer and on a fire grate in different sections of the roasting machine were obtained. The experimental data from technological control of the roasting conveyor machine were presented, as well as the results of chemical and granulometric analyses of roasting iron ore raw materials. Essential deviations in the thermal conditions of operating roasting machine in comparison with designed parameters were found out. The data on roasting conditions of iron ore raw materials in the experimental unit -the sintering pan, which provides simulation of the roasting conditions close to designed ones, are displayed. Insufficient heating in the lower layer levels at the operating roasting machines (in comparison with the designed parameters), stipulated by low speed of heat-carrying gas sweeping in the roasting area was revealed. Temperature heterogeneity along the width of a fire grate, caused by heterogeneity of heat-carrying gas sweeping due to segregation of iron ore material by its size during its loading to the roasting conveyor machine was substantiated scientifically.

The paper presents the review of the main technologies for concentration of rich iron ores and factors having influence on selection of the technology and concentration parameters. The most important technological parameters at the leading concentration plants (both abroad and in Russia), which are processing rich iron ores, are observed. It is shown that even ores with Fe content more than 65 % are subjected to concentration abroad. At present time, only 15 % of iron ores in CIS can be directed to metallurgical processing without concentration, 65 % of iron ores are concentrated via simple routes, but 20 % of iron ores require use of combined concentration methods. The aim of this work was study of substantial composition of large-lump hematite ore at Mikhailovskoe deposit and determination of possible technological pre-concentration methods for rise of Fe content in sinter ore up to 53-55 %. Examination of mineral composition of grab and bulk samples displayed that oxidized ferriferous quartzites are characterized by thin-layered texture with alteration of ore-free layers and interlayers, which are enriched by hematite. Coarseness less than 2 mm for more than 45 % of material proved presence of essential amount of slightly structured mineral differences and high oxidation degree. The experiments on determination of possibility of technological preliminary concentration of large-piece rich hematite ore were carried out using gravitation, X-ray absorption (XRT) and electromagnetic (EM) methods, dry magnetic separation in weak and strong field. It was shown that preliminary concentration of large-piece rich hematite ore from Mikhailovskoe deposit is impossible due to the features of mineral composition (wide range of porosity of ore lumps, Fe content outside the ranges of XRT method use, presence of essential amount of martite with relict magnetite nuclei etc.).

This paper describes a model of automatic mold flux (MF) feeding into the crystallizer of a continuous casting machine (CCM). The MF is used to protect metal from secondary oxidation, to lubricate the billet crust and the mold wall, and to fulfill some other functions. Most Russian steel plants use imported MF due to their higher quality and the use of imported CCMs. The effective consumption of MF is essential due to its high cost. Obtaining preliminary data from the model with the introduction of new equipment and expanding the range of steel in steel making shops is an urgent task. Therefore, a model of automated MF feeding has been developed, which can be modified by changing casting parameters. A detailed description of the model developed in Matlab Simulink software is provided. The distinctive features of the model include the relationships between the metal and slag temperature difference, slag layer thickness, and screw feeder flow rate. Mathematical expressions for these relationships are derived and a description of the structural automation diagram and the functional diagram of the model is presented. Model-based equipment settings (electric drive parameters and sensor parameters) and the introduction of the proposed control algorithm reduces flux consumption by up to 13 % while reducing the manufacturing costs of the final product by up to 6 %.

Among the alloying metals used in the smelting of high-quality steels, vanadium occupies a special place. Its introduction into steel, even in very small amounts (tenths and hundredths of a percent), provides significant improvement in the service properties of metal structures made from it. Global demand for vanadium ferroalloys exceeds its production. Lack of vanadium raw materials is the limiting factor for increasing production of ferrovanadium. Siliceous-carbonaceous ores of Karatau in Kazakhstan, amounting to more than four billion tons, are among the world's largest vanadium reserves. Although these ores contain up to 1% V 2 O 5 , they cannot be enriched, and there are no technologies for the rational vanadium extraction from them. This article presents the results of studies on the extraction of vanadium from ferrophosphorus, obtained during the complex processing of these ores together with phosphorites in the process of obtaining yellow phosphorus. The processes of oxidizingsodium roasting of industrial vanadium-containing ferrophosphorus (1.5 % V) and vanadium slag (10 % V 2 O 5 ) obtained during the converter processing of ferrophosphorus have been studied. It has been shown that watersoluble compound NaVO 3 is forming during oxidizing roasting of ferrophosphorus or slag in mixed with Na 2 CO 3 . With aqueous acid leaching of ferrophosphorus roasting cinder, vanadium extraction into solution is achieved up to 81 %, and with leaching of slag cake with Na 2 CO 3 -more than 92 %. Total V 2 O 5 extraction is 75 %.Mastering of the technology for processing phosphate and vanadium-containing siliceous raw materials at Kazphosphate LLP will expand the raw material base of vanadium and will allow creating a production facility for smelting more than 200 tpy of 50 % ferrovanadium.