Crystalline alumina samples with Al2O3 content of 95.23 wt.% were prepared directly from the nepheline ore in Nanjiang county, Sichuan province of China. Four steps were involved in the experiment of alumina preparation, including calcination, dissolution, carbonation and re-calcination. Lime was used in the calcination process with the nepheline concentrates powders to generate soluble aluminates and insoluble silicates. NaOH solution was used as the mother solution in the dissolution process. CO2 was introduced into the solution to precipitate the Al (OH)3 precursor, which was then fired to obtain crystalline alumina. Among the crystalline alumina obtained three phases of crystals existed which were detected by XRD and SEM, including δ-Al2O3 as the major phase, while θ-Al2O3 and κ-Al2O3 as the minor phases. Various crystal phases of alumina could be ascribed to the purity and crystal structure of precursor, as well as the re-calcination temperature and time.
The preparation of pellets with taking the iron concentrate and titanium concentrate as the raw materials, the pulverized coal as the reducing agent and the CMC as the binder were researched in this paper. It was deduced from the orthogonal experiment results that the impact of quantities of binders on the compressive strength is the greatest, carbon ratio takes the second place, water content takes the third place, and pressure the least; the impact of the water content on the drop numbers is the greatest, pressure takes the second place, carbon ratio takes the third place and quantities of binders the least. Suitable parameters of forming process are ore ratio is 1:1, quantities of binders is 2.5%, carbon ratio is 18%, water content is 8% and pressure is 16 MPa.
The typical chemical reactions of metal were analyzed in this paper, and the two-phase equilibrium line calculated model was obtained. By use of the physical properties database, the design of chemical reactions and the compounds were to be determined. Through the calculating the two-phase point and three-phase point ,the predominance area phase diagram algorithm based on the physical properties database was formed, which has clear physical meaning and accuracy calculation result, and also whose result was consistent with that of the literature.
The impact of activator varieties on the activation effect in preparing activated carbon with corncob adopting chemical activation process were researched in this paper, the results showed that phosphoric acid as the activator was much better than potassium hydroxide and zinc chloride. It was deduced from the orthogonal experiment results that the impact of activation temperature on the activation effect is the greatest, impregnation ratio takes the second place, and the activator concentration the least. Suitable parameters of activation process were obtained: when the activator concentration is 50%, activation temperature 500°C, impregnation ratio 2.7:1, the iodine value of activated carbon is 822.08mg/g.
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