Abstract: A nano-silicon-graphite composite negative electrode material with carbon coating and aluminum metaphosphate composite modification layer on surface and its preparation method are disclosed, which is mainly prepared from following components by mass percentage: 4-10 wt. % of aluminum metaphosphate, 10 wt. % of asphalt cracking carbon, 15 wt. % of spherical nano-silicon powder, and 71-65 wt. % of graphite powder. A nano-silicon powder is added to deionized water for ultrasonic dispersion to obtain a uniform dispersion, then graphite powder is added to mix uniformly, and then waterborne asphalt is added. After stirring and mixing evenly, spray drying is carried out, and the dried powder is compounded with metaphosphate for mechanical fusion. Finally, the same is transferred into vacuum furnace for high-temperature carbonization to obtain the product.

Abstract: This invention discloses a process for reducing sulphur dioxide emission from burning coal containing sulphur. In the disclosed process, pulverized combustible materials, such as coal, wood flour, combustible plant, charcoal, etc., and a sulphur trapping agent composition are mixed homogeneously to form an admixture which is ground to powder with dimension from about 30 mesh to about 60 mesh. With an improved roll briquetter of the present invention, briquettes with a microporous surface layer of said admixture powder can be prepared. In such briquettes, the atomic ratio of calcium in the sulphur trapping agent composition to sulphur in the pulverized coal is within the range of from about 1.0 to about 2.0. Microporous pellets of said admixture having opening-porosity are also prepared with conventional roll briquetter. The diameter of the prepared pellets is within the range from about 8 mm to about 20 mm. A layer of said pellets covers the surface of pulverized coal in a burner for combustion.