Physical Simulation Of Iron-Bath Smelting Reduction With Thick Slag Layer

In order to increase the reduction efficiency of iron oxide and reduce the coal consumption, iron-bath smelting reduction process with thick slag, which can prolong the cantact time of furnace charge and reducing zone and separate the oxidation zone from reducing zone by adding the thickness of slag,, has been developing nowadays.Taking ferro-alumininum ore smelting reduction process as an example, the mass balance and energy banlance of the prereduction unit, the final reduction unit and gas reforming unit was calculated, an iron-bath reactor which applies to the corresponding process was designed according to the results of mass balance. Based on the features of thick slag smelting, the blowing system includes three layers of side-blown lances and bottom blowing system which can alter the layouts of nozzles. Meanwhile, taking the principle of similitude as the theoretical basis, the corresponding physical model was established and the physical simulation study aiming at the mixing characteristics of fluid had been carried out. By the method of orthogonal experimental design, the influence of the operation parameters of side-blown lances to the mixing time of iron bath had been researched under the conditions of different blowing layouts; using the range analysis and variance analysis of mixing time, the optimal group of each blowing layout was obtained, which can provide analytical data for further optimizing the iron-bath smelting reduction with thick slag layer.According to the analysis of experimental results, the main conclusions are as follows:(1) When the blowing layout was only side-blowing, the mixing time reduced with increasing the angle and horizontal insertion depth of middle side-lance and the angle of lower side-lance. The mixing time decreased first with the increase of the horizontal insertion depth and then increased with the depth’s increasing.(2) After adding bottom blowing with single-nozzle, range value of angle and insertion depth of middle lance and angle of lower lance reduced sharply comparing with the only side-blowing condition, the influence of the angle and insertion depth of middle lance to the mixing time were relatively weak; while the range value of lower lance insertion depth significantly increased due to the decrease of injection flow rate.(3) In the circumstances of multi-nozzle bottom blowing, the mixing time with dual-nozzle layout was less than the value of four-nozzle conditions; when the number of bottom blowing nozzles was the same, the mixing time with asymmetric layout was less than that with symmetric layout.(4) Comparing the mixing time of optimal group of six kinds of blowing layouts, the best blowing layout was asymmetrical dual-nozzle blowing. The corresponding optimal operation parameters were that angle of middle side lance,50°; horizontal insertion depth of middle side lance,180mm; angle of lower side lance,50°; horizontal insertion depth of lower side lance,180mm. The average mixing time was9.7s.