Coal gangue is a kind of solid waste which is discharged from coal mining and coal washing. Dumped gangues do not only take a large land occupation but also pollute air and water. Treatment and utilizing of coal gangues has become the major issue for the coal industry to resolve. As major experimental material in this study, the coal gangue from Dawukou, Shizuishan, Ningxia province, China had been analyzed to have high-alumina content, and it could been used as alumina constituent for the preparation of sulphoaluminate cement. In this paper, alite-sulphoaluminate cements were prepared at 1330°C using coal gangue, limestone and gypsum as major main materials, fluorite and barite as minor materials. The result shows that major clinker minerals of the cement are sulphoaluminate, alite and belite, while major hydrate is ettringite, compressive strength of the cement is 48.9MPa after 7d. These experiments provide a new method of coal gangue comprehensive utilization.

A new kind of the micron-sized flaky silver-coated copper powder was prepared by electroless silver plating in this paper. Its plating structures were characterized by XRD, SEM and EDS. And a new kind of the electromagnetic shielding composite coatings containing 60 wt% the micron-sized flaky silver-coated copper powders and 40 wt% epoxy resin was prepared. Its electromagnetic shielding properties were analyzed by coaxial transmission line equipment. The study results show the micron-sized flaky silver-coated copper powders are composed of 91.35 wt% Cu and 8.65 wt% Ag and have high width-thickness ratio and crystal structure characteristics. In the frequency range of 0.3-1000 MHz, the shielding effectiveness of the coatings is up to 70.15-77.46 dB and increased an average of 22.18 dB compared with the coatings containing 60 wt% micron-sized flaky copper powders when the coating layer thickness is 300 μm. It is seen that the electroless silver plating method effectively improves the inoxidizability, conductivity and electromagnetic shielding properties of copper powders.

A new kind of the electromagnetic shielding composite coatings with high performance was prepared using the Ni-Cu-coated glass fibers and nickel powders as fillers and using epoxy resin as binder. The effects of the fibers on the conductivity and electromagnetic shielding effectiveness of the coatings were studied. The study results show as follows: 1) when the optimum ratio of the fillers to epoxy resin is 4:1, the coatings containing 6 wt% the Ni-Cu-coated glass fibers has best conductivity and electromagnetic shielding effectiveness; when the coating layer thickness is 300 μm, the shielding effectiveness of the coatings is up to 43.71-52.31 dB and increased an average of 13.94 dB compared with the nickel powders/ epoxy resin electromagnetic shielding coatings in the frequency range of 0.3-1000 MHz. This offers a new idea to enhance the added value of the glass fibers and the prevention of electromagnetic environmental pollution.

Electromagnetic radiation pollution and its protection has become one of the hot issues of urban development process. This paper analyzed the cause of natural and man-made electromagnetic environment pollution, pointed out the harm of public health and the city normal production and living order and the city sustainable development. This paper suggested that comprehensive treatment measures should be taken to solve the problem of electromagnetic environment pollution in cities including the reasonable planning and layout, the real powerful supervision, the advertisement and education, and the high level of protection technology. This plays an important role and realistic significance in building a harmonious urban electromagnetic environment.

The nickel ions in industrial wastewater derive from electroplating and chemical plating industry. Heavy metal ions can result in water pollution, and do harm to people’s health. Maifanite is a kind of nontoxic and harmless silicate rock mineral materials which have a certain biological activity. Maifanite porthole effect and surface effect can apply to removal of heavy metal ions from wastewater, for example, nickel ion, etc. However, natural Maifanite porous structure could be jammed by humus and sediment gradually; in order to play better adsorption performance of Ni (II) and other heavy metal ions in water, we need to adopt necessary modification treatment processes. H2SO4 was used to modify Maifanite, which prepared a high efficient adsorbent. At the same time, the removal effect of Ni (II) in water at different acid concentration, dosage, temperature, time and etc. was studied. The results showed that the Maifanite obtain better adsorption of 90% when the acid concentration was 2.5 mol/L, dosage of 50 mL, contact time and temperature of Ni (II) were 0.5 h and 30°C respectively. The above treatment has certain effect and meaning to reduce harm extent of industrial wastewater on environment and human health.