Materials Science Forum Vol. 847

Abstract: The resource intensity of primary nickel production in China was analyzed by the indicator of exergy, which can provide a unified picture about the overall processes involved in the life cycle of nickel. The results show that primary nickel’s CExD value is 235GJ_ex/t, and the largest contributor to the CExD is electricity (46%), followed by fuels (31%), mineral (16%), and land resource (7%); the considerable proportion natural mineral and land resource account for in the result is due to the high exergy value of sulphide minerals and the low grade of natural nickel ore. The results also show that the calculation of this study is sensitive to the choice of allocation basis (mass and market value); however, market value is not recommended in this study since that nickel’s price varies greatly over time.

Abstract: Based on Life cycle assessment (LCA) methodology, the carbon dioxide (CO2) emission of producing a typical electric vehicle (EV) IGBT module by the GaBi software has been analyzed. Carbon dioxide emission of each step, including raw material production, frontend, backend and transportation, of the whole life cycle was identified and evaluated. The results show that the CO2 emission of the frontend accounts for 51% of the total emission, and that of the backend accounts for 32.8%.

Abstract: Based on Life cycle assessment (LCA) methodology, this paper analyzes the total energy consumption and greenhouse gas (GHGs), NO_x, SO_x and PM emissions during material production and battery production processes of nickel-metal hydride battery (NiMH), lithium iron phosphate battery (LFP), lithium cobalt dioxide battery (LCO) and lithium nickel manganese cobalt oxide (NMC) battery, assuming that the batteries have same energy capacity. The results showed that environmental performance of LFP battery was better than the other three, and that of NiMH battery was the worst. The experimental results also showed the total energy consumption of LFP battery was 2.8 times of NiMH battery and GHGs emission was 3.2 times during material production, and the total energy consumption was 7.6 times of NIMH battery and GHGs emission was 6.6 times during battery production

Abstract: Ultraviolet (UV) absorber residue was used to modify bitumen. Effects of UV absorber residue on thermo-oxidative and UV aging properties of bitumen were evaluated by conventional physical properties and SARA (saturates, aromatics, resins and bitumenenes) analysis. The results showed that the viscosity aging index (VAI) and softening point increment (SPI) of bitumen decreased significantly due to introduction of the UV absorber residue, and the ductility retention rate (DRR) was evidently higher compared to the pristine bitumen. SARA show that UV absorber residue can effectively restrain the gelatinization of bitumen resulted from aging. As a consequence, the UV absorber residue modified bitumen displays enhanced aging resistance properties, which can be attributed to the physical sorption of activated carbon to lighter components in the thermo-oxidative aging process and the absorption of UV absorption residue to the ultraviolet light in the process of UV aging.

Abstract: Effect of three de-icing additives: NaCl, wrapped NaCl (W-NaCl) and Layered double hydroxides (LDHs) on thermo-oxidative and ultraviolet aging properties of bitumen were investigated by thin film oven test (TFOT), pressure aging vessel (PAV) and ultraviolet (UV) radiation test. The experimental result illustrated that compared with bitumen with MF, the softening point and viscosity of bitumen with NaCl and W-NaCl increased and the ductility decreased distinctly after TFOT, PAV and UV aging, indicating that NaCl and W-NaCl accelerated the aging of bitumen. However, for bitumen with LDHs, the softening point and viscosity decreased significantly, the ductility increased after aging, which demonstrated that the anti-aging properties of bitumen were improved effectively by LDHs.

Abstract: Layered double hydroxides (LDHs) surface modified by silane coupling agent KH550 were prepared to modify bitumen, the surface modified LDHs (KH550-LDHs) were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD). The effect of KH550-LDHs and LDHs on physical and anti-ageing properties of bitumen was evaluated by means of physical test. The results of FTIR showed that KH550 had successfully grafts onto the surface of LDHs, and XRD result showed that KH550 had little effect on the crystal structure of LDHs. The storage stability test showed that KH550-LDHs dispersed better homogeneously and existed more stable than LDHs in bitumen. The physical properties tests indicated that high and low temperature properties of bitumen were improved compared with LDHs. After UV aging with the addition of KH550-LDHs, the increase rate of softening point slowed remarkably, the reduction rate of ductility declined evidently compared with LDHs. Aging indices (softening point increment and ductility retention rate) show that KH550-LDHs exhibited better improvement than LDHs in UV aging resistance of bitumen, implying more effective modification of KH550-LDHs which is due to the enhanced compatibility between KH550-LDHs and bitumen.

Abstract: Three-dimensional depth of field microscope (3-D FM), scanning electronic microscope (SEM) and molecular dynamic simulation (MD) were used to evaluate the surface morphology, behaviors and failure mechanisms of mortar and fine aggregate mixture (FAM). The effects of ultraviolet (UV) light and moisture for FAM, the interfacial behaviors of bitumen-aggregate were investigated. Results showed that in the pure mortar, the UV-ageing could increase the adhesion between the bitumen and fine aggregates, and the cohesion failure was dominant after UV-ageing. Due to the lower air voids in the pure mortar, the moisture did not cause the adhesion failure. The molecular dynamic simulation implied that UV ageing and moisture-treatment could reduce the interfacial energy, and the aromatic and asphaltene played a great role in the adhesion between bitumen and aggregate.

Abstract: In recent decades, high-tech electrical equipment has drastically proliferated instead of Cathode Ray Tube (CRT), making CRT funnel glass potential hazardous solid waste. Due to a relatively high level of lead, CRT funnel glass could be used as a potential material for the production of anti-radioactive concrete. In our study the CRT funnel glass , which was separated as aggregate in the concrete, was reduced to 4.75-25 mm (coarse aggregates) and less 4.75 mm (fine aggregates) in the production of anti-radioactive concrete. Mixes containing 0%, 20%, 40% , 60%, 80% and 100% (volume percentage) of CRT funnel glass to replace fine aggregate and coarse aggregate (respectively or simultaneously)) were prepared. The influence of the size, shape and replacement percentage of aggregates on workability, compressive strength and radiation shielding performance were determined. It was found that the replacement of natural aggregate with recycled CRT glass considerably improved the slump and radiation shielding performance but reduced compressive strength. The optimum percentage of waste funnel glass used as fine aggregate and coarse aggregate was 40%. The results clearly showed that the CRT funnel glass performed a significant enhancement in radiation shielding properties.

Abstract: The effect of graphite oxide (GO) on the mechanical properties of oil well cement was experimentally studied, in view of the zonal isolation failure due to the brittleness. The microstructure of cement stone was observed by SEM, and the mechanism of graphite oxide reinforced cement stone was also investigated. The result illustrates that the mechanical properties of cement was improved significantly due to the addition of GO. When the GO dosage was 0.05%, the compressive strength, flexural toughness, and splitting tensile strength of cement paste at 7 day age were increased by 61.32%, 15.46% and 145.34% respectively. GO had no bad effect on the application properties of cement slurry, and the stability of the slurry was favorable. Besides, GO could reduce the fluid loss of cement slurry. When GO reinforced cement stone undergoes damage under complex stress, if damage occurs within graphite oxide layer, chemical bonds of GO layers must have been broken, and the force between the layers of GO must be overcome when interlaminar peeling happens, which will lead large amounts of energy consumption as well. The mechanical properties of the cement stone were enhanced by the above two aspects. The research results can provide a theoretical reference for solving the brittle fracture of oil well cement stone.

Abstract: To design oil well cement paste system and ensure well cementation quality of adjustment well in work area of tertiary oil recovery (EOR), the composition, microstructure and strength of cement paste matrix eroded by producing water were tested and studied by HTHP Curing Chamber, HTHP corrosion tester, X-ray diffraction, scanning electron microscope (SEM), universal testing compressor and some other laboratory equipment according to the condition that producing water contains sulfate (SO₄^2-) and bicarbonate (HCO₃^-). The corrosion law and mechanism of oil well cement paste matrix were analyzed. The problem for designing corrosion resistance oil well cement paste system was investigated. The corrosion law and mechanism of oil well cement paste matrix by SO₄^2- and HCO₃^- were raised. The corrosion resistant oil well cement paste system was designed, which was suitable to the adjustment well in area of EOR in Daqing. The results show that the compositions of cement paste matrix changed after corrosion by SO₄^2- and HCO₃^- for a long term. The secondary gypsum, ettringite and calcite were produced, which changed the microstructures and declined the compressive strength of cement paste matrix. The change degree of compressive strength of cement paste matrix was affected by corrosion media concentration, corrosion time and other conditions. The higher concentration of corrosion media and the longer of corrosion time were, the greater decline of cement strength occurred. The formula of corrosion resistance oil well cement paste system was designed, for which the high sulfate resistant cement as architectural substrate and the PZW as admixtures were used to improve the strength and penetration resistance ability of cement.