| China is one of the richest countries in magnesite(MgCO3) resources which accounts for one third of world magnesite production. Liaoning province is the richest area in magnesite reserves in China with 3.4 billion tons of proved reserves which accounts for about 90% of magnesite resources in China and 25% in the world.Thermal decomposition of magnesite was investigated by using non-isothermal TG-MS. Different kinetic analysis methods including Flynn-Wall-Ozawa Kissinger,and Coats-Redfern were applied to investigate the thermal decomposition kinetics of magnesite. It was observed that the activation energy values are obtained by three different ways but the results are similar. The average apparent activation energy was found to be 203 KJ/mol. The ore and decomposition products of magnesite at the different constant temperature in N2 are tested by FT-IR, XRD, and SEM. It was analyzed in the function groups, crystal structure and composition, and apparent morphology. The magnesite was completely decomposed at 700 oC and it becomes MgO which is the trigonal crystal from MgCO3 which is the hexagonal crystal.It investigates the effects of magnesite calcination temperatures and time on activation of magnesium oxide. The citric acid and XRD methods were used to detemine the activation of magnesium oxide. It was observed that the activation of magnesium oxide was dependant on calcination temperatures and time.The results showed that magnesium oxide obtained at 650 oC and 45 min had the best properties.The magnesium oxides obtained at 650 oC for 45 min showed the highest reactivity.The magnesium oxide obtained at optimum conditions were used for wet flue gas desulfurization. Magnesium oxide prepared from MgCO3 was investigated and used for desulfurization of wet flue gas in a bubbling reactor. The effects of various parameters such as desulphurization temperature, concentration of magnesium oxide,different SO2 concentration and O2 concentration in flue gas on desulphurization efficiency were studied. The pH value of desulfurization solution decreased significantly at the beginning of reaction and then levelled off at later stages of reaction. The results showed that at pH values greater than 6, the desulfurization efficiency of magnesium oxide reached 100% under different experimental conditions.Desulfurization efficiency also increased at longer residence times at 40 oC.Increasing the concentration of MgO also increased the desulfurization efficiency. At higher concentration of SO2 in flue gas the reaction rate was higher. When O2 was present in flue gas, the product was oxidized and the desulfurization efficiency decreased. Desulfurization products were analyzed by XRD and STA-MS. XRD and STA-MS analyses showed that the main desulfurization products were MgSO3 and MgSO4 in the absence of oxygen and MgSO4 in the presence of oxygen. |
