الفهرس 
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Abstract
Production of Pure Magnesium from Egyptian Dolomite Ore by Magnetherm Process Heba Hussein Mohammed
The present study is concerning with the extraction of magnesium metal from Egyptian dolomite ores usmg Magnethermic technique. In this technique, the dolomite was roasted and then its magnesium oxide content was reduced by ferrosilicon in a baby magnethermic electric arc furnace in the presence of a liquid basic slag under inert atmosphere. This slag is used as reduction bath. The charges were used in the form of sintered briquettes. The sintering parameters investigated were briquetting pressure range of (4.9 - 9.8 MPa), sintering temperature (700-1 100°C), and sintering tinie (1- 3hr). The reduction temperature range was from (1450-1750°C). The maximum reduction extent of about 80% was obtained at reduction temperature 1550°C for 15 minutes. The reduction kinetics was discussed. The results showed that it can be represented by one of the following two solid state diffusion models, (i) [1-(1-X) 113]2=kJ t, or (ii) 1-(2/3) X-(1-X) 2/3. =kG t
anywhere kJ, kG: rate constants, t: time, x: reaction extent. The calculated apparent activation energy was found to be 498 kj/mol. The mechanism of the reduction process was postulated. Effect of some additions on the reducibility was examined. The addition of alumina retarded the reduction process while addition of 2.5 wt% calcium fluoride increased the reducibility by about 12% also, the flowsheet of magnesium production from dolomite ore using magnethermic technique was postulated.