Preparation Of Alumina And Silica Using Residue Of Fushun Oil Shale

In the processes of oil refining industry, burning system and power generation process using oil shale will produce residue of oil shale, it will not only bring unnecessary pollution and destruction to environment, but also waste of resources if directly throw away. This paper intends to preparation alumina and silica to explor a suitable way to make good use and recycle of residue.The work take residue of Fushun oil shale as raw material, Al2O3 in material converts into AICl3 by means of acid leaching reaction at first, and then SiO2 converts into Na2SiO3 through alkali leaching reaction. Using single-factor method research influence of activation temperature, activation time, granularity of raw material, concentration of HCl and NaOH solution, liquid-solid ratio, reaction temperature and reaction period on leaching rates of Al2O3 and SiO2 were obtained. The optimum technological conditions of Al2O3 and SiO2 leaching process are as follows:the activation temperature is 850℃, the activation time is 1.0h, the granularity of raw material is 0.074mm; The optimum acid leaching conditions are listed as follows:the concentration of acid is 12%, the liquid-solid ratio is 5:1, reaction temperature is 100℃, the reaction period is 1.5h; The optimum alkaline leaching conditions are as follows:the concentration of NaOH solution is 6mol/L, the liquid-solid ratio is 5:1, the reaction temperature is 90℃, the reaction time for 3.Oh. The leaching rates of Al2O3 and SiO2 are 81.75% and 80.01% respectively.Homogeneous chemical precipitation method was used in the alumina preparation. Optimum technological conditions of alumina preparation are determined by single-factor research method. The result is as follows:the reaction goes at 55℃for 1.5h, the concentration of sodium meta aluminate is 0.4 mol/L, the dose of surfactant is 0.3% of total system quality. the purity can be effectively improved by acetic acid solution(25%) wash,γ-Al2O3 is 0.216μm(d5o), and the degree of purity is 98.7%.Using CO2 replacing strong acid as latent acidifier and combining highly selective separation method of acetic acid study, the silica was prepared from filter cake that gets from acid leaching process and the influence of preparation process on particle size of silica. The results show that optimum technological conditions of modification preparation silica are as follows:the reaction temperature is 50℃, the concentration of sodium silicate 0.027g/L, CO2 flow is 20ml/min, the dose of surfactant is 0.007g/ml of volume of total system. The white powder silica was spherical approximately, and the average particle size(d50) was 20-30nm. the product could be comparable with the relevant national standards, degree of purity is 98.4%. It provides a new way for the development and utilization of residue of oil shale,.