Table 2 - uploaded by Bitan Kumar Sarkar
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In the present study, isothermal reduction kinetics of titaniferous magnetite ore (TMO) fines (below 75 µm particle size) using coke dust, an industrial waste, in the form of briquettes have been performed at temperatures ranging from 1273 to 1473 K over varying reduction times: 5, 10, 20, 30, 40 & 60 min. This process aims at the efficient utilisa...
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... dust, used as reductant, is collected from the coke oven by-product plant (COBP) of the Vizag Steel Plant (VSP), India. The composition of coke dust has been analysed by using standard proximate as well as ultimate analysis (LecoTruSpec) and are tabulated in Tables 2 and 3, respectively. Figure 1. ...
Citations
... The results showed that the most suitable kinetic model for this reaction was found to be a diffusion-controlled model (Jander equation). Sarkar et al. [9] also investigated the reduction of briquettes of titaniferous magnetite ore (TMO) fines using coke dust at temperature ranging from 1000 o C to 1200 o C with varying the reduction time ranging from 5 to 60 minutes. They found that the maximum degree of metallization was 89.56% and the reaction activation energy was 59.52 kJ.mol -1 . ...
Mill scale is a valuable waste material that contains high amount of iron, little impurities and also is chemically stable composition. It is produced from the hot rolling processing in steel industry. The second waste is El-Dekheila pellets fine waste that produced as the results of handling in the El-Dekheila plant, West of Alexandria on the Northern coast of Egypt. This paper studies the recycling of mill scale and El-Dekheila pellets fine waste in iron and steel industries by reduction using coke breeze in the form of pellets. Characterization of raw materials were performed which are XRF, XRD and screen analysis. Reduction of pellets consisting of El-Dekheila pellets fine waste and different percentage of mill scale was investigated with 4 stoichiometric coke breezes using thermo-balance. The reduction increases with increasing coke breeze. The kinetics of reduction of these pellets were studied using different percentage of mill scale (20,60 and 80%) and at different temperatures ranging from 900 to 1050 o C. The results displayed that the reduction process was controlled by Avrami and Erofeev involving nucleation of reduced phases followed by grain growth. Also, that the maximum reduction 80% can be reached after 125 minutes using 20% mill scale. The activation energies of reduced 20, 60 and 80% mill scale were found to be 112 kJ.mol-1 , 81 kJ.mol-1 and 107.8 kJ.mol-1 respectively.
The possibility of recycling large-tonnage waste of heat power engineer-ing and mining industry in road construction is shown. Compositions of road-building materials were researched, containing siftings of rock grinding, fly ash, Portland cement, modified with a stabilizing additive of polymeric nature. X-ray phase analysis showed availability of quartz in fly ash, calcite, feldspars, goethite and X-ray amorphous phase, what is consistent with the data of infrared spectroscopy. By atomic emission spectrometry with inductively coupled plasma it was revealed that fly ash is latent-active and can be disposed in compositions in the presence of a stabilizing additive. The X-ray phase analysis of grinding siftings showed that it contains quartz, feldspars, chlorite, calcite and dolomite. The specific activity of natural radionuclides (226Ra, 232Th, 40К) of fly ash and grinding siftings was 248 and 110 Bq/kg, which allows using such waste in construction without restrictions. It was revealed that the initial mineral raw materials belong to multiphase polymineral systems; therefore, when modifying them with stabilizing additives, binding of finely divided particles should be taken into account. It was revealed that the optimal content of Portland cement and fly ash in samples is 8 and 10 wt.%. It was found that an increase in the mass fraction of fly ash in the composition of soil-concrete up to 30 wt.% leads to softening of the samples and a decrease in their strength characteristics.
