بررسي پارامترهاي موثر بر تصفيه منيزيم توليدي به روش ريتورت

چكيده انگليسي :

Evaluating the parameters affecting on purification of magnesium produced by retort process Amir Gorji a gorji@ma iut ac ir Department of Materials Engineering Isfahan University of Technology 84156 83111 Isfahan Iran Degree M Sc Language FarsiSupervisors Dr M Ahmadian Assoc Prof E mail ahmadian @cc iut ac irDr M Panjepour Assoc Prof E mail panjepour@cc iut ac ir AbstractOne of the most important thermal techniques used in the production of magnesium isSilicothermic method But this method of magnesium is associated with impurities thatresulting from the production process and raw materials and may not be removed Theimpurities in the mechanical creep fatigue etc and chemical properties corrosionresistance of magnesium has a negative effect So the purification process and theproduction of high purity magnesium ingots and homogenous are important In this study the morphology and the purity of magnesium is obtained from the retort furnace arestudied Also simultaneous influence type of flux the relaxation time and metallurgicalfactors including the amount of turbulence in the melt on the refining process wasevaluated For this purpose the resistance furnace that Adjustable temperature up to 900 C and agitation was used Beginning the furnace temperature to 710 C is set and thenraw magnesium and flux is charged into the crucible After melting magnesium mixerenter the melt and beginning to rotation with speed 193 rpm for time period of 5 10 and15 minutes Then melt in periods of 5 15 30 and 45 minutes kept in the furnace andfinally casting into the mold To evaluate the structural phase samples and samplesobtained from retort furnace used from optical microscope and scanning electronmicroscopy SEM equipped with electron diffraction spectroscopy system to EDSanalysis and X ray diffraction analysis XRD was used The percentage of deposits inpurified samples with using optical microscopy images and the software Clemex wasdetermined Also for optimize and determine the exact elements and impurities tests XRFand ICP were used The results of this research show that the temperature of thecondenser is the main factor affecting the speed of crystal growth and structuralmorphology magnesium obtained As temperatures rise from the outlet of the condenserto the retort furnace magnesium crystal grains are larger and will be more compactstructure Magnesium in different areas of the condenser has not been the same purity andsome is variable Magnesium formed at the outlet of the condenser has the lowest purityand the area near the retort furnace has most of the purity However by increasing therelaxation time of the melt in the purification process reduces the amount of impuritiesand remaining deposits in purified magnesium is smaller more rounded shape anddistribution is more uniform in the background In the relaxation time as well as than 10minutes or more than 30 minutes increasing duration of melt stirring has little effect onthe removal of impurities The results showed that the use of flux with 5 and 15 weightpercent of CaF2 has little effect on the removal of impurities and protect moltenmagnesium But use of flux with a chemical composition 47MgCl2 28 KCl 15 NaCl 10CaF2 in relaxation time of 30 minutes and melt stirring for 5 minutes at speed 193 rpmand direct input of about 0 2 CaF2 can be increase purity magneisum around 99 percentto 99 9 percent Keywords Magnesium refined Flux impurities

گرجي، امير

بررسي پارامترهاي موثر بر تصفيه منيزيم توليدي به روش ريتورت

فلاكس , ناخالصي