Papers by Keyword: Pellets

Abstract: This article presents the results of research on the development of an effective technology for the production of non-fired pellets using a binder additive and a reducing agent. The proposed method will make it possible to obtain pellets using material of class 0-5 mm, i.e. eliminates the costliest part of the pellet production technology - regrinding. It is also important that the non-fired agglomeration of the material almost unchanged the composition and properties of the feedstock, as a result of which the reduction processes in them begin earlier and proceed more intensively. Using the results of physical and chemical studies, a technology has been developed for pelletizing fines of manganese ore from the Western Kamys deposit using clay from the Sazdinsky deposit as a binder and smelting ferrosilicon manganese using manganese pellets.

Abstract: Questions about the oxidative roasting of iron ore raw materials (agglomerates and pellets) are studied. Features of the phase structure of the iron ore raw materials containing titan and vanadium are discussed. Reducibility, durability, and the softening and melting temperatures of metallurgical iron ore raw materials are studied in vitro. The objects of the research are titaniferous ores containing different amounts of titan dioxide. The behaviors of agglomerates and pellets in a blast furnace are studied, and the influence of their physical and chemical properties on heat and mass transfer processes are researched by means of a mathematical model. The main indices of blast furnace smelting—productivity, coke consumption, composition of top gas, cast iron, and slag—are shown. It is established that the increase in titanium dioxide content in pellets, as the amount of concentrate with increased TiO₂ content increases, does not cause deterioration in the quality of iron ore raw materials being prepared for blast furnace smelting. At the same time, as the hot strength of raw materials increases, the temperature at which softening begins increases and the temperature interval of softening of materials decreases.

Abstract: The metallurgical characteristics of pellets (reducibility, strength after reaction, softening start and end temperatures), phase composition (X-ray phase analysis), and porosity were studied. Blast furnace smelting parameters were calculated using laboratory pellets with different basicities and degrees of metallization. Pellets were obtained from complex titanium-magnetite ores. The vanadium extraction of this ore into metal did not exceed 10 % during smelting of metallized pellets in an arc steelmaking furnace, but special techniques could raise this to 85 %. According to calculations from the Institute of Metallurgy of the Ural Branch of the Russian Academy of Sciences (IMET UB RAS), vanadium extraction up to 80–90 % can be achieved by using high-base and partially metallized pellets. The influence of changes in the composition and metallurgical characteristics of titanomagnetite pellets with increasing basicity (especially relative to strength after reduction) should be taken into account.

Abstract: The reducibility of titanomagnetite iron ore materials (agglomerate, pellets) with various TiO₂ contents are studied. The mineralogical features of agglomerate and pellets before and after reduction are investigated. Calculations of technical and economic indicators of blast furnace smelting using iron ore materials with different TiO₂ contents are carried out. It is shown that an increase in the content of titanium dioxide in pellets and agglomerate (with an increase in the amount of concentrate introduced into them) does not change the quality of iron ore preparation for blast furnace smelting.

Abstract: Firing of various basicity pellets and sintering of Kachkanar concentrates were evaluated on a pilot plant. Mineral analysis was carried out for fired pellets and those reduced in a derivatograph in gas with composition close to that of blast furnace gas. Structure and metallurgical property dependence of pellets and agglomerate on their basicity was studied. Failure mechanism of fluxed pellets was considered. Blast furnace smelting process was developed for Kachkanar iron ore raw material with various fluxing degree, consisting of low-basic pellets, and high basic agglomerate characterized by low failure characteristics at reduction and ensuring high gas permeability in blast furnace top. Optimal values of agglomerate basicity, carbon content in burden and ferrous oxide in agglomerate, ensuring its high reducibility and adequate reduction degree index, were determined. Optimal ratio of pellets and agglomerate in a blast furnace, which implementation contributes to improved furnace performance, was detected.

Abstract: Every year a huge amount of plant refuse from production of grain, oil-bearing and other crops-remains, the bulk of which has a negative impact on land and water resources. Research in the field of rational use of plant refuse showed that one of the most promising areas of use of plant refuse is obtaining organic fertilizers. At the same time, advanced research in this area concerns the production of bio-char, used as soil modifiers. In this case, the most important characteristics of the product are porosity, surface area and pH, which can be set by adjusting operating parameters of the pyrolysis process. The purpose of the research is to study the effect of pressure on the process of pyrolysis of pellets, made from the husks of sunflower, and the analysis of the main properties of the coal produced. It is established that a decrease in the pressure of the medium, leading to the forced removal of volatile substances, causes a decrease in temperature in the reaction zone, thereby increasing the duration of the pyrolysis process. However, at the same time, an increase in porosity and surface area of the obtained bio-char is observed. Thus, the feasibility of further research in this area, in order to obtain optimal temperature and pressure parameters in the process of pyrolysis of sunflower husk, was determined.

Abstract: We have developed the process that enables receiving pellets from zinc-containing dust and recovering them in a Waelz kiln with practically total zinc distillation and its capture in bag filters. As this takes place, metallic iron, still present in the pellets, can be used in metallurgical treatment. We have elaborated the process instructions to obtain pellets from zinc-containing dust with an addition of solid fuel, magnesite, and bentonite. To simulate recovery of the carbon-containing pellets in production, bench tests have been performed. These allowed us to determine principal operating conditions of the technological procedure of metallurgical zinc-containing dust recovery and validate the unit for recovery of this dust. The data obtained from the production tests prove feasibility of implementation of this process and allow assessing economic efficiency of zinc-containing dust recovery.

Abstract: The questions of oxidizing roasting of iron ore raw materials with production sinter and pellets are considered. The question of reduction roasting of iron ore raw materials is studied. Phase transformations of oxidizing and regenerative roasting are considered. Features of phase transformations of iron ore raw materials containing titanium are discussed. The reducibility, durability and temperatures of softening and melting of metallurgical iron ore raw materials are studied In Vitro. The effect of the durability of burned iron ore pellets on compression is also defined.

Abstract: The article considers the problem of improving the technology of obtaining energy-saturated materials, which results in an improvement of the characteristics of energy granules. We developed a technique for pretreatment of raw matirual in a continuous mode on a vertical vibratory mill. This contributes to the production of particles of the optimal granulometric composition.

Abstract: Solid state sintered pellets of barium hexaferrite were performed. The Curie temperature of BaFe₁₂O₁₉ pellets were measured with differential scanning colorimetry (DSC). The coefficient of thermal expansion (CTE) of pellets was defined above and below the Curie temperature. The Curie temperature calculated basedon the dilatometry is are in good agreement with the DSC measurements.