Theory and Practice of Sintering of Iron ore Nov25

Theory and Practice of Sintering of Iron ore...

Theory and Practice of Sintering of Iron ore Sintering of iron ore is a generic term which is used to describe the process whereby a sinter mix (raw mix or green mix) of iron ore fines, fluxes, fuel (coke breeze) and plant return fines (e.g. mill scale, blast furnace dust, and returned sinter fines etc.) are converted into a particular form of agglomerate. It consists of heating the sinter mix with a particle size of less than 10 mm to such a temperature that surface of each grain of the charge mix starts to melt and the formed melt creates liquid bridges between grains, which, after solidification, ensure formation of a solid porous material called sinter having a screened size normally of 5 mm to 30 mm (upper size can go upto 50 mm to suits local requirements), and which can withstand operating pressure and temperature environment inside the blast furnace (BF). The process of sintering is a thermal operation involving melting and assimilation reactions. The first stage of the sintering process is the formation of the melt which involves the reaction between fine iron ore particles and fluxes. The initial melt is generated from adhering fines during heating via reaction between iron ore and fluxes. Then, nucleus particles are partially assimilated or dissolved into the primary melt to form more melt. Before complete melting is achieved, the sintering temperature drops due to the short residence time at the maximum temperature and then the melt solidifies and mineral phases precipitate, resulting in the formation of the bonding phases. During the sintering process, the chemical reactions are taking place at high temperature and the iron ore and fluxes are combined together and form a sinter cake composed of iron ore, silico-ferrites of calcium and aluminum...

Sinter Quality and Process of Sintering Iron Ores Nov21

Sinter Quality and Process of Sintering Iron Ores...

Sinter Quality and Process of Sintering Iron Ores Sinter is normally the major component of the blast furnace (BF) charge burden. Sinter consists of many mineral phases produced during process of sintering of iron ores. The quality and properties of sinter are dependent on the mineral structure of sinter. However, since the sintering conditions are usually not uniform throughout the sinter bed, the phase composition, and therefore the sinter quality, varies in the sinter bed. The structure of sinter is not uniform. It consists of pores (of varying sizes) and a complex aggregate of mineral phases, each with different properties. It is the combination of these pores and mineral phases, and the interaction between them that determines the sinter quality, but also makes the prediction of sinter properties very difficult. Though a large number of investigations have been carried out on sinter, still the correlation between the chemical composition and mineralogy of sinter with its properties and behaviour is still not clearly understood. Schematics of sinter mix and the product sinter are at Fig 1. Fig 1 Schematics of sinter mix and product sinter  Sintering process is a generic term that is used to describe the process of agglomeration of a green mix of iron ores, fluxes and coke and plant solid wastes having a particle size of -10 mm so as to produce sinter  which can withstand operating pressure and temperature conditions existing in a BF. Solid wastes such as dusts, sludges, slags and mill scales etc. are used for their utilization in sinter mix because of the complex chemical structure and mineral components of these materials. The process of sintering is described in detail in a separate article which is available under the link http://ispatguru.com/the-sintering-process-of-iron-ore-fines-2/ During the process of sintering, as the...