The Experimental Research Of Coal Gongue Used In Producted Industrialsilicon Materials And Utilizable Maximization

The coal gangue from the twelfth Mining of China PinMei Energy and Chemical Group contained higher Silica and lower Alumina . Furtherly, using silica, aluminum and other valuable elements in coal gangue made for series of products with the existing chemical technology through extracted research. We obtained series of high valuable of the products, such as Al2O3 , industrial silicon,and so on .It at last increased the value of gangue using. The main conclusion as follows:1.The best extracting factor of acid leaching as follows: determined degree 0.15mm, calcination temperature 780℃, calcination time 2h, hydrochloric acid 15%, liquid to solid ratio 6:1, extraction temperature 50℃, extraction time 3h . In this condition, the Alumina, Iron and Silicon extracted rate reached 67.4%, 89.3% and 0.9%. Through this method, it removed the main impurities of producted the industrial silicon, and the Al2O3 prouduted by leaching solution reached the second standard of the Al2O3 Quality Standards.2.The route of Gangue used to product industrial silicon as follow: alkali soluble→silica hydrogenated→silane purification→silane decomposition. Among of them, The best extracting factor of Alkali leaching is NaOH concentration 15%, liquid to solid ratio 0.8:1, extraction temperature 100℃, extraction time 4h, and the Silicon extraction rate reached 67.4%; Using the catalyst of Al and AlCl3 , the Silica can be hydrogenated into Silane in the condition of 400 atm and 175℃; Silane purification as follows: preheating decomposition→hydrolysis→sulfuric acid oxidation purification→4A zeolite; The best factor of the Silane pyrolysis to be Silicon as follows: Silane concentration 0.25%, carrier gas flows 200l/h, decomposition temperature 850℃, decompose pressure 0.35 KPa . In this condition, the Silicon deposition rate reached 89.3%, at the same time the silicon powder deposition rate reached 6.2%, not deposited 4.5%. At last, the silicon reached the first standard of Industrial Silicon Quality Standard, and the polysilicon reached the third standard of the Polysilicon Quality Standards (Submitted version). 3. The salt prouducted by prosess of coarse can be used as the materials of chlor-alkali process,and the suplus of slag can be used as the materials of producted the cement. At last, the coal gangue comprehensive utilization rate about to 80% throught the whole process.