Modeling of air flow through sinter mix bed

The present work relates the flow of air through a packed sinter mix bed to the pressure drop using the Ergun’s Equation. The velocity of air infiltration across the sinter mix charged into a pot was measured at different suction pressures. The parameters, void fraction and equivalent spherical diameter were calculated using the pressure drop and air velocity relationship. These have been interpreted in terms of the process variables vis-à-vis the mix permeability The validity of the Ergun’s equation was checked while comparing the observed pressure drop with the computed one obtained by fitting the above parameters in the equations

Effect of flux granulometry and other process variables on the sintering of iron ore at high basicity

Elimination of raw limestone from the blastfurnaee burden is known to bring a considerable saving in coke rate. In a country like India or elsewhere, the capacity of the sintering plants is limited it is imperative to produce super fluxed sinter and use it in the furnace. The basicity requirement coupled with the higher gangue input through coke and iron ore demands for a greater amount of flux in the mix. This situation is different from the frequentl y reported prac¬tice elsewhere in the world. So the flux size has crucial effect in the sintering. However this has not been reported adequately. In order to bridge the gap in the literature, sintering study was carried out using factorial design. Five factors were studied at two levels. Data generated through the experiments were analysed using the statis¬tical procedure and the regression equations were established for the following sintering indices in terms of significant factors and interactions. The flux granulometry has crucial role in the produc¬tion of sinter at basicity level of 3.25. The sintering indices are adversely affected when the sinter mix contains higher amount of ¬0.5 mm size fraction in it. The thermal and X-ray diffraction analy¬ses of the sinter and return fines sample reveal that the limestone is not properly calcined properly to be assimilated by hematite. A sav¬ing in the consumption of coke breeze upto 10% can be achieved through improvement in gasodvnamic in the sintering bed when -0.5 mm size fraction in limestone is restricted. Based on the above ob¬servation a modification in the existing crushing scheme of lime¬stone are proposed

Improvement in Quality Parameters of Super-Fluxed Sinter from Indian Iron Ores: NML’s Experience

The various studies at NML report that the quality parameters of sinter could be improved by modifying the physical characteristics of the sinter mix and improving the thermal efficiency. The studies have shown that increasing the solid fuel consumption was not a viable solution to improve TI and RI simultaneously. The mineralogical and morphological compositions of sinter do affect its qualities : A higher amount of calcium ferrites improved the reduction-degradation index and reducibility of sinter. The reducibility was well correlated with the ratio of micro-pores to total pores in sinter. Grain size of the mix did affect the sintering speed and quality parameters. The studies also show that significant improvement in reduction properties could be achieved by narrowing down the flux size and that of coke as well as optimizing the process variables. The RDI also improved with the addition of polymer in the mix, however, sinter productivity decreased

Application of Statistical Analysis in Sintering and Blast Furnace Iron Making

Statistical techniques are used to represent a physical situation functionally and/or to confirm a hypothesis. Statistical techniques are of considerable help in analyzing the performance of a complex system, such as a blast furnace , which is subjected to a large number of inter-influencing variables

Coke Making from Coal: Scope for SSI

The technological developments have opened up new avenues for small scale industries (SSI). The SSI sector has proved its mettle even in the changed liber-alised economic environment of the nation. The SSI sector is riddled with certain problems. It is therefore need of the hour to strengthen the SSI sector and enhance its competitiveness domestically and globally — for this the sector must be provided sustenance through suitable measures

Fundamentals of Iron Ore Sintering

The process of sinter making originated from a need to make use of fines generated in mines and in ore bene-fiCiation plants. With the development of sintering technology, a sintering plant has become a tremendous success for providing a phenomenal increase in prod-uctivity and saving in coke rate to the blast furnace. The technology of sinter making has undergone radical changes both in operation and process throughout the world. High competitiveness amongst the iron and steel industries has forced the operators to radically modify their operat-ion in several fronts including the raw material preparat-ion through sintering. In this regard It is essential to understand the sintering fundamentals

Malignant Melanoma of Nose and Paranasal Sinuses: 2 Case Reports

Malignant melanoma is one of the rare and highly aggressive diseases of the sinonasal cavity. High index of suspicion is required for diagnosis as the patient usually presents with non specific signs and symptoms. In the natural course of the disease, higher rate of loco regional recurrences and distant metastasis are seen making the overall prognosis of disease very poor. In reviewing the various treatment modalities used in the past, surgical resection of the tumour with postoperative radiotherapy is preferred one. Advances in surgery, radiotherapy and chemotherapy don’t have any impact on improved survival, which remains poor in this disease. We report two cases of malignant melanoma, which were treated at our institute

De-Watering of Iron Ore Fine Particles in Aqueous Medium

Solid - liquid separations form an integral part of many mineral processing and hydrometallurgical operations. During the wet processing of iron ores, a considerable amount of fine particles, known as slimes, are generated which need to be recovered effectively through solid -liquid separation. This assumes even more importance in case of iron ores in view of the large tonnage treated in India or elsewhere in the world. Proper dewatering is essential

Inter-influencing factors in affecting BF coke rate – statistical approach

A blast furnace (BF) is a multivariate system which is subjected to a large number of inter-influencing variables affecting its performance: productivity and coke rate. It is important to isolate the inter-influence before drawing any conclusions. It is essential to support the parameters’ effect (on the responses) through theoretical consideration. . The explanatory variables affecting the coke rate have been statistically analysed in case of typical BF at Bhilai Steel Plant, SAIL and discussed in the present paper. The results (sixteen years’ monthly average data points) show that some variables are not orthogonal which have been explained in terms of (a) natural cause and effect relationship amongst the variables and (b) apparent inter-relationship amongst the explanatory variables and masking the effect. The inter-influences of the variables have been isolated and their effect on coke rate has been discussed which are substantiated by the theoretical consideration. The study shows that the variable, burden rate was the most significant one followed by temperature of hot blast. A change in burden rate has been mainly reflected by a change in weight of raw limestone in the burden.. The adverse effect of the variables, ash content of coke was inter-influenced by the variable, limestone consumption. However, analysis shows the variable, ash content in coke affected the coke rate, though marginally when the inter-influence was isolated. The range studied against this variable during the period was quite high: 12 to 554 kg/ THM which indicates that lump ore constituted high proportion in the burden with nearly zero sinter consumption during some period. The empirical equation, established through the analysis of more recent data shows that an increase in ash content of coke (range 21.5- 26.6%) increased the carbon rate and the correlation coefficient was similar to those observed previously. The study indicates that an equation developed need to be modified when the value of an independent variables deviates from the range of data considered in the analysis

Improved gravity separation : typical case studies in relation to slimes

The present paper describes typical case studies of improved gravity separation of slimes in relation to (a) the separation of synthetic mixture of blue dust and kynite (concentration criterion 2) in advanced gravity separation equipment, and (b) preparation of bauxite feed following stage-grinding and size classification for enhanced separation following WHIMS. A sort of size classification has been achieved over the deck of belt concentrator which necessitates need to treat the slimes in a narrow size range, especially when the concentration criterion is less. A significant better yield and better grade of the products has been observed while following an improved method of feed preparation (stage grinding and size classification) vis-à-vis those following conventional one (grinding and de-sliming) for their separation