Analysis of chemical-metallurgical agglomeration processes during charge sintering

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.

Section: Introductionmentioning

confidence: 99%

Experimental examination of the chemical-metallurgical roasting process for iron ore raw materials on the fire grate of a roasting conveyor machine

Bobkov,

Dli,

Kulyasov

2023

“…At present time, development of power-and resourcesaving technologies and their putting into practice in the Russian metallurgical industry are considered as the most important directions of development of this industry at present time [1][2][3]. It is evident that these technologies can be applied with maximal efficiency in the industrial branches which are using mineral resources; concentration of iron ore ram materials can be related to such industries [4,5].…”

Section: Introductionmentioning

confidence: 99%

Influence of the conditions of internal heat exchange on the process of thermal decomposition of carbonates in iron ore raw materials

Bobkov¹,

Dli²,

Rubin³

2022

This work considers influence of heating rate of iron ore raw materials on chemical and metallurgical processes of thermal dissociation of carbonates, which occur during its high-temperature roasting. The research was conducted for the temperature ranges of the existing roasting and sintering machines, taking into account macro-kinetics of calcination processes. Substantial influence of heating rate of iron ore samples on kinetics of thermal decomposition of carbonates was revealed. The cause of the effect of internal heat exchange conditions in reacting iron ore sample on macro-kinetics of dissociation reaction for carbonates was substantiated scientifically. Influence of nonisothermal properties on precision of thermal analytical investigations, which were conducted using the methods of non-isothermal kinetics with different heating rates of iron ore samples, was studied. The authors suggested the mathematical model, which allows to take into account wide range of variations of the parameters in kinetic equations and volumetric thermal and chemical-metallurgical dissociation processes for carbonates. A series of calculating experiments, aimed on reveal of the relationship between heating rate of iron ore samples and evolution of concentration fields, transformation rates and temperature gradients, was carried out using the suggested model. The obtained results can be used for development of the optimal operating conditions for sintering and roasting machines, which propose optimization of heat treatment processes for iron ore preparation, owing to intensification of heat and mass exchange processes during high-temperature roasting. These conditions are considered as optimal from the point of view of power-and resource efficiency. Forming of the above-mentioned conditions allows to decrease fuel and power expenses for thermal preparation of raw materials at metallurgical production facilities, as well as to lower total economical production charges due to use of thermal decomposition of carbonates.

“…Lack of information about decarbonization kinetics of iron ore raw material as well as about the effect of chemical and mineralogical composition, material structure and heating rate on calcination process don't allow to use the existing literature data on the results of thermal analytical researches of separate types of iron ore raw material and "clean" carbonate materials for description of calcination process of iron ore raw material [1][2][3]. Thereby, experimental investigation of the processes of carbonates dissociation with use of samples saving their initial material structure within the temperature range close to practical range is required for establishing the general regularities of calcination chemicalmetallurgical process [4,5].…”

Section: Introductionmentioning

confidence: 99%

Features of research of iron ore thermal decarbonization kinetics during roasting

I.¹,

Бобков²,

Kulyasov³

et al. 2021

The work is devoted to research of chemical-metallurgical decarbonization process in iron ore pellets, taking into account thermal and technological operation features of roasting conveyor-type machines. Calcination of pelletized iron ore raw material was experimentally examined, using the samples that save their initial structure within the temperature and heating rate ranges of the existing roasting conveyor-type machines. Appearance of essential temperature gradients in the examined samples was proved experimentally; it was connected with non-stationary heating conditions and thermal effects of carbonates dissociation reaction. These conditions and effects restrict possibility of use of the existing non-isothermal kinetic methods for determination of kind and parameters of kinetic equations. The relationship among heterogeneous endothermic transformations and thermal physical calcination conditions was revealed.