Advanced Materials Research Vols. 955-959

Abstract: Aimed at the common problems of small backfill space, hard to backfill, difficult to guarantee compaction quality in engineering, development law of fluidity and mechanical properties (unconfined compressive strength and cleavage strength) is analyzed by changing mix ratio of cement, fly ash and water. Fluidity is mainly controlled by water content. Range of fluidity is significantly different when water content is around 60％.Considering the effect of economy and strength, 4% cement content will be recommended.

Abstract: The flotation is the effective method to fine coal separation, but the cost is higher and flotation reagents pollute circulating water system. In this paper, the JiuLiShan coarse coal slim was classified, the interception of 0.25 mm was collected, fine coal float-and sink test was carried out. For the-0.25mm coarse slime, compare the flotation, conventional coarse coal slime separation and new slime separator separation, the results show: underflow ash increased by 12.4%;the new slime separator is suitable for the 0.25 mm granularity fine coal slime, can be applied to lower fine slime ash, raising cleaned coal yield.

Abstract: The glass-ceramics of CaO-Al₂O₃-SiO₂ system were prepared by sintering using lead-zinc tailings. Orthogonal experiment was carried out to optimize the ratio of lead-zinc tailings, chemical composition of basic-glass and other chemical materials in the system. Crystallization heat treatment conditions were confirmed by the differential thermal analysis (DTA) curve of glass aggregate. Crystalline phase, crystal morphology and mechanical property of the glass-ceramics samples were studied by means of X-ray diffraction (XRD), scanning electron microscope (SEM), hardness and bending strength test. The results indicated that the optimized ratio of the samples was lead-zinc tailings 25%, quartz 46.63%, calcite 21.05%, Al₂O₃ 10.19% and nucleating agent TiO₂ 1%. The optimized crystallization heat treatment was that basic glass was first heated to 800 °C at 10 °C/min, then 800°C-900 °C at 5 °C/min and held still at 900 °C for 2 h. After that, the basic glass was heated to 1230 °C at 1-1.5 °C/min,held for 1h. At last, the glass-ceramics was obtained after the cooling-down of the system. The main crystalline phase of microcrystal glass-ceramics are diopside. The hardness and bending strength were 9.14 GPa and 213.6 MPa, respectively. The glass-ceramics had excellent chemical durability in acid and alkali solution, with weight losses of 0.17% and 0.68%, respectively.

Abstract: In this paper, the de-silicated fly ash (DSFA) was sintered with soda and calcium oxide. Detailed analysis and characterization was carried out by using thermal gravimetric analysis (TGA) and X-ray diffraction (XRD). Two dominant reactions take place in the sintering process. The kinetics was studied by using Jander mode, and the sintering activation energies were determined based on the weight loss of CO_2.

Abstract: The paper discusses the disposal of kitchen garbage by means of comprehensive utilization. The method includes four steps: pretreatment of kitchen garbage; preparation of biodiesel from oil-phase by transesterification; Rhizopus oryzae TZY1 and Saccharomyces cerevisiae TZY0 were co-inoculated into water-phase for fuel ethanol production; preparation of protein feed from solid residue of fermentation. Advantage of the method is to make good use of the kitchen garbage, simplify the disposal process, with good prospects for industrial utilization.

Abstract: Biological pretreatment of municipal solid wastes (MSW) has been proved to be a practice capable of reducing the ammoniacal nitrogen content in the leachate. In this study the transformations of nitrogen were investigated during a short-term biological pretreatment of mixed MSW by using static pile composting. The performance of a large-scale biological treatment process had been studied on about 100 tons of raw municipal solid waste for 16 days. MSW samples were collected at different stages of the process and analyzed to investigate the evolution of nitrogen forms. The results indicate that the ammoniacal nitrogen concentration increased during the first 3 days and decreased subsequently. Ammonia volatilization likely contribute to the reduction of the ammoniacal nitrogen content assessed. The total nitrogen content reduce from 5.5g/kg to 2.1g/kg and the production of nitrites and nitrates is negligible during pretreatment. This data indicate that 16 days of static pile composting with low aeration would be sufficient.

Abstract: Biosorption of Cr^{6 +} ions by industrial fermentation waste Aspergillus niger free dry mycelium was investigated in a batch system..The influences of Cr^{6 +}concentration, biosorbent dose, solution pH and contact time on Cr^{6 +}were investigated.Optimum biosorption was observed to be 73.5% at pH 5,biosorbent dose 20g/L, initial Cr^{6 +} concentration 100 mg/L. Adsorption equilibrium was established in 800 min at 30°C. The Langmuir model compared to the Biosorption equilibrium data were best described by Langmuir isotherm model, R²=0.9999.

Abstract: Normally, because the water content is generally high in vegetable waste, the quality of aerobic composting can not be guaranteed. In order to solve this problem, this experiment, regarding lettuce waste and pumpkin straw as researching objects, by adding corn straw as auxiliary materials, chicken manure and cattle dung as regulators, conducts research on the process of aerobic fermentation and the ammonia volatilization in this process. The experiment sets up six treatments in total, they are respectively: A1 (lettuce + corn straw), A2 (lettuce + corn straw + chicken manure), A3 (lettuce + corn straw + cattle dung), B1 (pumpkin straw + corn straw), B2 (pumpkin straw + corn straw + chicken manure) and B3 (pumpkin straw + corn straw + cattle dung). After all treatments being mixed, the aerobic compost is conducted through aeration oxygen-supply and the physicochemical properties and material changes in the composting process have been monitored. The results show that: adding cattle dung has a greater impact on the process of vegetable waste composting than adding chicken manure, where, the germination indexes (GI) A3 and B3 adding cattle dung are respectively 7.10% and 3.44% higher than those of A2 and B2 in adding chicken manure; after the composting the C/N of all treatments are lower than their initial values and reach a significant level (P<0.0001), among them, C/Ns of A3 and B3 decrease to the greatest extent, which are 52.84% and 53% respectively; in the whole composting process, the quantity of ammonia volatilization in treatments adding chicken manure (A2 and B2) is significantly higher than that of adding cattle dung (A3 and B3). On the whole, adding cattle dung can better promote the decomposing process in vegetable waste composting and reduce nitrogen loss than adding chicken manure under conditions in this experiment.

Abstract: Phytoextraction of heavy metal polluted environment generates large quantities of hyperaccumulators. How to safely dispose hyperaccumulators has been one of the most important issues in the phytoextraction field. In recent years, disposal technologies for hyperaccumulators have been extensively studied with aim at reduction, recycle and harmless treatment. This paper reviewed the progress in disposal technologies for hyperaccumulators, such as Incineration, composting, burial method and so on. Focused on summaring the disposal technology for arsenic-containing hyperaccumulator Pteris vittata L.. Also pointed out the problems of the current disposal of hyperaccumulator and the possible research direction we should pay attention to in the future, hoping to provide insight into developing harmless disposal or resource-reuse-oriented methods for disposal of the plants used for large scale phytoremediation application．

Abstract: Abstract: Surface response optimization of adsorption conditions of neutral red wastewater by brewer's grains with the factors of pH value, initial concentration,adsorption temperature, adsorption time, adsorbent quantity and the response of adsorption rate were studied. The optimal parameters for adsorption conditions were of adsorbent concentration of 191.24 mg·L-1, adsorbent particle size of 60~80 mesh,pH 4.65, adsorbent amount of 2.56 g·L-1, adsorption time and temperature of 1.92 h and 30°C, respectively. The maximal absorption rate got 99.16%.The brewer's grains is a promising, cheap, efficient, new biological materials of adsorption for neutral red in wastewater.