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1.
1 Results Chemical modification of polymer plastic wastes to useful products can be one of the way of effective waste plastics management (chemical recycling). Chemical modification of polymers and polymer plastic wastes can yield products with suitable physical and chemical properties. In consequence they can be used as polyelectrolytes[1]. The variety of pollutants, universality of various water and sewage treatment technologies, introduction of new water quality improved technologies have caused a growth in demand for polyelectrolytes and ion-exchange polymers with specific parameters. The most important use of polyelectrolytes is their application in industrial water treatment and in aiding sediment-centrifuging processes. Their application significantly lowers the coagulant consumption, shortens the flocculation time and improves the sedimentation properties of suspensions[2, 3].  相似文献   

2.
A water cooling treatment was applied in the coal-based reduction of high-chromium vanadium and titanium (V–Ti–Cr) iron ore from the Hongge region of Panzhihua, China. Its effects on the metallization ratio (η), S removal ratio (RS), and P removal ratio (RP) were studied and analyzed on the basis of chemical composition determined via inductively coupled plasma optical emission spectroscopy. The metallic iron particle size and the element distribution of Fe, V, Cr, and Ti in a reduced briquette after water cooling treatment at 1350°C were determined and observed via scanning electron microscopy. The results show that the water cooling treatment improved the η, RS, and RP in the coal-based reduction of V–Ti–Cr iron ore compared to those obtained with a furnace cooling treatment. Meanwhile, the particle size of metallic iron obtained via the water cooling treatment was smaller than that of metallic iron obtained via the furnace cooling treatment; however, the particle size reached 70 μm at 1350°C, which is substantially larger than the minimum particle size required (20 μm) for magnetic separation. Therefore, the water cooling treatment described in this work is a good method for improving the quality of metallic iron in coal-based reduction and it could be applied in the coal-based reduction of V–Ti–Cr iron ore followed by magnetic separation.  相似文献   

3.
MgO·Al2O3 spinel type inclusions in casing steel were analyzed by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS).The results show that there are three forms.One is pure MgO·Al2O3 spinel,another is the composite oxide of the Mg-Al-Ca-Si-O system,and the third is the complex with oxide as a core covered by sulfide.The formation mechanisms were studied.The influences of slag basicity and vacuum degree on the magnesium content during the vacuum treatment of molten steel and furnace lining in molten steel were calculated with the coexistence theory of slag structure.The results show that the magnesium content increases with the increase in slag basicity and aluminum content in molten steel,and decreases with the increase in CO partial pressure.  相似文献   

4.
Evaluation of seedling emergence is a common method used to investigate the vegetation restoration potential of soil seed banks. Previous studies have primarily been conducted in the laboratory using a single water treatment. However, when this method is used, it is difficult to optimize the water conditions for the needs of the individual species of seeds. Additionally, the germination conditions for seedlings in the laboratory are different from those in nature. To avoid these issues, we conducted experiments to activate soil seed banks in the field using different water treatments. The results revealed that: (1) generally, the number of species and quantity of seedlings decrease gradually as the water supply decreases, but that for several species most seedlings did not appear when they were provided with the greatest amount of water, and (2) different species present different germination characteristics. According to the rate of seedling emergence, the species were classified into two germination types: fast and slow. In addition, each species also had a unique climax period of emergence, which was delayed with a decrease in water supply. Therefore, the amount of water provided is vital to seedling emergence, and various water treatments should be evaluated when studying the characteristics of different species in soil seed banks. For the lower reaches of the Tarim River, the optimal soil moisture for seedling emergence ranged from 23% to 28%, and seedling conservation should be strengthened during the climax period of emergence (9–15 days from the day when water became available). These results highlight the importance of the use of an optimal water treatment and demonstrate the danger of using a single treatment method. Our results also emphasize the need for a preliminary study prior to conducting studies to evaluate seed banks.  相似文献   

5.
The relationship of species and abundance between the diatoms in the water and sediments from the southern South China Sea (SCS) were discussed, and the key environmental controlling factors were also investigated. Studies show that the diatom abundance is high in both water and sediments in the southeast part of the southern SCS and the varying trend is similar, while in the northwest part, the abundance is low, and the varying trend is different. The dominant diatom species are Thalassionema nitzschioides and Nitzschia bicapitata in water, and T. nitzschioides and Chaetoceros messanensis in sediments. The diatom species of small size and thin shell in water are more than in the sediments, while the diatom species of large size and thick shell in water are less. The percentage of species T. nitzschioides is higher in water of southeast part than in that of northwest part, but it is similar in sediments of both areas. It is shown that the southwest monsoon is the important factor influencing diatom abundance and T. nitzschioides percentage, and when the southwest monsoon is well developed, the distribution of diatom abundance and T. nitzschioides percentage are consistent in both water and sediments of the study area.  相似文献   

6.
The process characteristics of heat treatment of aluminum alloy auto body sheet and the working principle of air cushion furnace were introduced. The process position and irreplaceable role of air cushion furnace in the aluminum alloy auto body sheet production was pointed out after the difficulty and key points in the whole production process of auto body sheet were studied. Then the development process of air cushion furnace line of aluminum alloy sheet was reviewed, summarized and divided to two stages. Based on the research of air cushion furnace, the key technology of it was analyzed, then the key points on process, equipment and control models of air cushion furnace for aluminum alloy auto body sheet in future were put forward. With the rapid development of automotive industry, there will be certainly a new upsurge of research and application of air cushion furnace for heat treatment of aluminum alloy auto body sheet.  相似文献   

7.
Taking extruded Al-Zn-Mg-Cu alloy (7A04 alloy) bars as the research object, the effect and mechanism of pre-annealing treatments on the microstructure and mechanical properties of the aged alloy bars were investigated. The results show that a pre-annealing treatment at 350℃ for 15 h before a T6 treatment substantially reduced the sensitivity of the microstructure and mechanical properties of the extruded 7A04 aluminum alloy specimens toward the extrusion temperature. The average grain sizes of the specimens extruded at 390 and 430℃ after T6 treatment were 3.4 and 8.1 μm, respectively, and their elongations to failure were 7.0% and 9.2%, respectively. However, after pre-annealing + T6 treatment, the differences in both the grain sizes and the elongations of the specimens became small, i.e., their average grain sizes were 3.2 and 3.8 μm and their elongations were 12.0% and 13.3%, respectively. For the specimens extruded at the same temperature, pre-annealing treatment obviously improved the plasticity of the alloy, which is attributed to an increase in soft texture or to grain refinement in the specimens as a result of the pre-annealing + T6 treatment.  相似文献   

8.
In order to remove the low turbidity present in surface water, a novel metal-polysilicate coagulant was used to treat the raw water taken from Tanjiang River in Guangdong Province. This study on the effects of A1/Fe molar ratio on the performance of a complex compound formed by polysilicic acid, aluminium and ferric salt (PAFS) showed that PAFS with A1/Fe ratio of 10:3 seemed to have the best coagulation performance in removing turbidity and color. Experimental results showed that under the conditions of polymerization time of 15 d, sedimentation time of 12 min, and pH of 6-8,PAFS with A1/Fe molar ratio of 10:3 had the best coagulation efficiency and lowest residual A1 concentration. The turbidity decreased from 23.8 NTU to 3.23 NTU and the residual A1 concentration was only 0.165 mg/L in the product water. It could be speculated that colloidal impurities and particulate A1 were removed by adsorption bridging and electrical neutralization of long chain inorganic polymer coagulants.  相似文献   

9.
The effect of vanadium carbide (VC) on the grain size of commercial pure aluminum was experimentally investigated by varying the content of VC, the holding time, and casting temperature. The refining efficiencies of VC and Al5Ti1B were also compared. The refined samples of commercial pure aluminum were examined using optical microscopy, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The results suggest that VC is a good refiner of commercial pure aluminum. The addition of only 0.3wt% VC can decrease the grain size of aluminum to 102 μm, whereas the casting temperature and holding time have little effect on the grain size. The refining efficiency of VC is better than that of Al5Ti1B. The VC particles in molten aluminum act as nuclei and the grain refinement of aluminum alloys by VC particles is achieved via heterogeneous nucleation.  相似文献   

10.
There has recently been great interest in ablative photodecomposition(APD), notably in pulsed UV laser treatment on polymers, for modification of physical and chemical properties, such as dyeability, printability, adhesion, Iuster and many more. Very little attention was focused, however, on the property of wetting behaviour,which is one of the most fundamental properties in affecting polymer science. Poly(ethylene terephthalate) (PET) fibers drawn to two different draw ratios and under two temperatures, and three white knitted polyester fabrics made of 100% PET fibre were used to investigate their wetting behaviour due to excimer laser treatment.Experiments like water contact angle measurement, vertical drop test and moisture regain were conducted upon samples and all results give the same conclusion that laser treatment increases the hydrophobicity of all samples tested. Scanning electron microscope (SEM) observation reveals how the morphological modification of polymers by laser treatment is correlate  相似文献   

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