Advanced Materials Research Vols. 356-360

Abstract: Nowadays, huge quantity and various kinds of municipal solid waste (MSW) are collected mixing together without separating in China. There are wastes such as plastic, glass, metal, chemical fiber, paper, food and so on that can be regenerated and reused after sorting to realize sustainable development. However, because MSW are complex mixtures and with high moisture content, results in that useful substance can’t be sorted entirely, to research efficient equipments successfully is the key to solve this problem. Aiming at wastes easily to wind and hook each other such as cloth, strings, plastic and so on, a new sorting equipment was designed. Some key parts of the equipment were analyzed and optimized by using design calculation, finite element method and kinematic simulation method, including the structure optimum of the cam, and kinematic simulation and analysis of reset springs to promote the performance and reliability.

Abstract: An experimental study has been performed on the desulfurization performance of the original magnesium slag (from the process of magnesium production). The total content of CaO and Ca₂SiO₄ is near 90% in the slag, but its conversion rate is below to 30% as desulfurizer directly in the experimental conditions. The aim of this paper is to enhance the performance of the slag by the hydration treatment process. In the hydration process, the slag, additives and water are mixed proportionally in slurry, then dehydrated and dried. Compared different slag performance by TGA, the optimal hydration method is found. The results show that a much higher calcium conversion rate (about 40%) of the slag is obtained after the hydration process. By means of XRD, Sorptomtic Instrument and SEM, the related parameters of the original slag and the hydration treated slag are analyzed. It is found that the composition, appearance and surface area changed obviously. The principle is basically studied that the hydration may enhance the desulfurization performance of the slag.

Abstract: The efficient reclamation of printed circuit board (PCB) is of important significance to environmental protection, optimal configuration of resources and development of circulation economy. In the paper, several important physical mechanical recycling strategies of PCB were analysed, and a cost-profit evaluation model for these recycling strategies was established to evaluate reclamation profit quantitatively. With one specific recycling example, an accurate economic analysis of it was given by the use of the evaluation model. Finally, the best recycling strategy of the mainboard was acquired and some suggestions were given to improve the reclamation economy.

Abstract: In the paper, magnetic flocculation was used in high turbidity mine water treatment. The results show that the magnetic flocculation is one of efficient methods in removing the COD and SS of high turbidity mine water. It finds the optimal conditions: the PAFC was 30mg/L and added with the fast stirring speed being 250r/min for 2min; then, 50mg/L magnetic particle was added with slow stirring speed staying 50r/min for 7min. The wastewater is treated under the optimal condition, the removal efficiency of SS and COD reached 94% and 71% respectively.

Abstract: In this paper, the Huainan No.1 Sewage treatment plant's dehydrated sewage sludge and the power plant fly ash have been taken as the main raw materials and clay as the cementing agent to prepare lightweight ceramsite. Using the single-factor experiment to screen roasting craft, the optimal conditions are obtained as follows: the clay content is approximately 15%, sludge content 35-40%, preheating temperature 350-400°C.The preheating time is 15-20mins, roasting temperature 1150-1200°C, roasting time 15-20mins. The product’s loose density is 710-750kg/m³, particle density 1305-1380kg/m³, compressive strength 13.2-15.2MPa, bibulous rate 12.4-18.1%, particle shape factor 1.3-1.4, specific surface area 5.68-6.01m²/g. The performance index can meet the national standard requirements for fly ash ceramsite in the light collection aggregate. This lightweight ceramsite may serve as the water treatment material, the building material and the thermal insulation material and so on. This research had not only solved the problems of contamination caused by sludge and solid wastes like fly ash, but also brought certain economic and environmental benefits.

Abstract: Water treatment ceramic particles were prepared using dewatered life sludge in Huainan No.1 Sewage treatment plant and power plant fly ash as main materials and clay as the bond. Through the L9 (43) orthogonal test, we obtained the best conditions of the preparing process. The product can be used as water treatment packing ceramic particles and simulated adsorption experiment with the wastewater including Pb^{2 +} was conducted. The results indicate that ceramic particles (used as wastewater treatment filler) bibulous rate is 25.0%, the loose density is 690kg/m³, the particle density is 1240kg/m³, specific surface area is 5.997m²/g, the compressive strength is 9.40MPa and the adsorptive performance is excellent. The toxic metal leaching experimental result shows that the concentration of toxic heavy metals in leaching solution is in the range of GB specification and the performance of product is stable which will not cause second pollution.

Abstract: Based on the comprehensive experimental test-bed of blast furnace slag waste heat recovery, we study the impacts which are caused by the changes of the key parameters, such as blast furnace slag discharged temperature, the speed of the granulation device, on the particle diameter distribution and sphericity, so as to master the best operating parameters of the blast furnace slag dry granulation, and provide experimental basic materials for blast furnace slag waste heat recovery. The results show that: when the discharged temperature of the blast furnace slag is controlled in 1400°C～1450°C, and the speed of the granulation device is controlled above 2000r/min, the sphericity is better, and 80% of the particle’s diameter will be 2～5mm.

Abstract: In this paper, the characteristics and the present disposal state, trend of organic solid waste have been described. Four new technologies of organic solid waste energy utilization were proposed and the technical principles, features, contents and progress of these technologies were analyzed, respectively.

Abstract: To learn differences between Chinese domestic and imported paper-process reconstituted tobacco (RT), their physical properties and chemical components were tested systemically and in-depth. The results indicated that: (1) Domestic RT were generally similar to the imported on physical properties. There were just some slight differences in filling power, combustibility (domestic RT were better than the imported), and density (the imported slightly lowered than the former). And all products were advised to improve their water contents. (2) Imported RT were higher in contents of total sugar, reducing sugar, nicotine and protein than domestic samples, whereas lower in Potassium contents; (3) Although there were no significant differences in contents of volatile alkali and total non-volatile acid between domestic RT and imported RT, volatile acid contents of the former were lower than that of the latter. Also all pH value of samples was near equal and showed very weak acidic. (4) Contents of poly-phenol, chlorogenic acid, rutin and petroleum ether extract of imported RT were higher than that of domestic products, while cellulose contents were lower. (5) The overall high contents in total sugar, reducing sugar, nicotine, volatile acids, malic acid, total poly-phenols and petroleum ether extract, may be main factors of good taste and aroma of imported products.

Abstract: A Brazilian fly ash sample (CM1) was used to synthesize zeolites by hydrothermal treatment. Products and raw materials were characterized in terms of real density (Helium Pycnometry), specific surface area (BET method), morphological analysis (SEM), chemical composition (XRF) and mineralogical composition (XRD). The zeolites (ZM1) from fly ash were used for metal ion removal from water. Results indicated that hydroxy-sodalite zeolite could be synthesized from fly ash sample. The zeolite presented higher specific surface area and lower SiO₂/Al₂O₃ ratio than the ash precursor. The adsorption showed that cadmium is more preferentially adsorbed on ZM1 than zinc. The adsorption equilibrium time for both Zn²⁺ and Cd²⁺ was 20 hours in a batch process. The adsorption isotherms were better fitted by the Langmuir model and the highest percentages of removal using ZM1 were obtained at pH 6 and 5 and doses of 15 and 18 g L^-1 for Zn ²⁺ and Cd²⁺ , respectively. Thermodynamic studies indicated that adsorption of Zn²⁺ and Cd²⁺ by ZM1 was a spontaneous, endothermic process and presented an increase of disorder at the interface solid/solution.