共查询到20条相似文献,搜索用时 125 毫秒
1.
Kazuki Morita Muxing Guo Norio Oka Nobuo Sano 《Journal of Material Cycles and Waste Management》2002,4(2):93-101
This research focused on the treatment of steel-making slags to recycle and recover iron and phosphorus. The carbothermal
reduction behavior of both synthesized and factory steel-making slag in microwave irradiation was investigated. The slags
were mixed with graphite powder and heated to a temperature higher than 1873 K to precipitate a lump of Fe–C alloy with a
diameter of 2–8 mm. The larger the carbon equivalent (Ceq, defined in the text), the higher the fractional reduction of iron and phosphorus. An increase in the SiO2 content of slag led to a considerable improvement in the reduction for both iron and phosphorus because of the improvement
in the fluidity of the slags and an increase in the activity coefficient of P2O5 in the slags. The extraction behavior of phosphorus from Fe–P–Csatd alloy was also investigated at 1473 K by carbonate flux treatment. For all the experiments with a processing time longer
than 10 min, the phosphorus in the fluxes could be concentrated to more than 9% (w/w) showing that it could be used as a phosphorus
resource. Compared with K2CO3 flux treatment, that using Na2CO3 was more effective for the extraction of phosphorus, and this was attributed to the lower evaporation of Na2CO3. Finally, a recycling scheme for steel-making slag is proposed.
Received: March 16, 2001 / Accepted: November 12, 2001 相似文献
2.
Masahiro Shimada Takahiko Iida Kensuke Kawarada Takayuki Okayama Masami Fushitani 《Journal of Material Cycles and Waste Management》2001,3(2):135-143
We have already reported the adsorptivity and pore structure of activated carbon made from waste newspaper in order to use
the waste paper for purposes other than paper-making stock. However, manufacturing the activated carbon may not necessarily
be an advantageous method based on environmental concerns and the effective use of the resource because the reaction during
the activating process is endothermic and the amount of carbon consumed is significant. Here, we examine the pore structure
and adsorption properties of waste newspaper used as an adsorbent in the form of a carbonized material. Waste newspaper was
carbonized for 2 h in the temperature range 400°–1000°C. The specific surface area of the carbonized material obtained, 418 m2/g, was highest for the sample carbonized at 800°C, which was equal to or greater than that of commercially available charcoal.
Moreover, the iodine adsorption number of 581 mg/g was the highest and the rate of adsorption was the fastest for the sample
carbonized at 800°C. However, the humidity control capability was highest for the material carbonized at 600°–700°C. It has
been determined that it is advantageous to carbonize waste paper at 800°C in order to use the carbonized material as an adsorbent,
while carbonization at 600°–700°C is more advantageous for use as a humidity control material.
Received: June 23, 2000 / Accepted: January 17, 2001 相似文献
3.
The emission of waste in an economy, including landfill, is to a large extent determined by its patterns of technology, institutions,
and lifestyle. A mathematical model (the waste input–output model) is presented that gives a simple analytical representation
of this interdependence. The model was used to evaluate the effects of alternative waste disposal and recycling options on
the levels of industrial production, landfill consumption, and the emission of carbon dioxide, and also to analyze the overall
dependence on landfill of individual industries. It was found that a systematic combination of the options could be effective
in reducing the overall landfill consumption and carbon dioxide emission.
Received: November 4, 2000 / Accepted: August 2, 2001 相似文献
4.
Il-Chung Kim 《Journal of Material Cycles and Waste Management》2002,4(1):12-22
This paper considers the current status of waste generation and waste treatment trends, and introduces a wide variety of policy
instruments for waste minimization at every stage of economic activity in Korea, i.e., production, distribution, and consumption.
At each stage, the Korean government has imposed a policy mix of direct regulations and economic incentives. These policy
instruments have made definite contributions to a reduction of waste generation and an increase in the recycling rate. Despite
these fruitful outcomes, there are still some shortcomings with respect to efficiency and equity. Among other aspects, this
paper examines three representative economic incentives – the charge system, the volume-based-collection fee system, and the
deposit–refund system – and identifies shortcomings in each. Some suggestions are made for the creation of better systems
of economic incentives. However, many experts insist that this kind of piecemeal change in each policy instrument is not enough
to achieve the ultimate goal of resource circulation and an environmentally friendly society, especially in Korea, which is
a country with little land, a high population density, and a high economic growth rate. Among experts, special emphasis is
placed on the activation of recycling industries to achieve these goals.
Received: April 2, 2001 / Accepted: September 10, 2001 相似文献
5.
Shun'ichi Honda Naoyuki Miyata Keisuke Iwahori 《Journal of Material Cycles and Waste Management》2002,4(1):46-50
In our previous work, the primary sludge from wastewater treatment plants was shown to contain a considerable amount of cellulose
(about 20%, based on suspended solids) owing to the discharge of toilet paper. For the purpose of using the cellulose as a
biomass resource, this study examined a simple method for its recovery. When fibrous cellulose was suspended in 0.3% sulfuric
acid and autoclaved at 130°C for 60 min, 85%–88% of the initial solids remained without dissolving. Under these conditions,
an activated sludge sample not containing cellulose was strongly hydrolyzed and only 7% of the initial solids remained. The
prescribed amounts of cellulose added to the activated sludge sample were quantitatively recovered by the autoclaving treatment.
In the treatment of primary sludge containing >20% cellulose, residual solids with relatively high levels of cellulose (>69%)
could be obtained. The results indicate that the method proposed here could recover cellulose practically from waste sewage
sludge for biomass utilization.
Received: July 17, 2000 / Accepted: July 4, 2001 相似文献
6.
A national Baumol–Oates tax on waste in Denmark helped achieve a reduction of 26% in net solid waste from 1987 to 1998. The
tax, which is levied per ton of waste, was particularly effective as regards the heavier waste streams such as construction
waste and garden waste. When it comes to industrial and commercial waste, there are indications that the waste tax is not
sufficiently significant to induce changes in behavior, and that except for very waste-intensive enterprises, companies do
not seem to be very price sensitive. For household waste, the impact of the tax can be improved where tariffs for garbage
collection are weight based, rather than per unit. However, the waste sector is an area in which the price signals are modified
and filtered by institutionalized practices in municipal administration, and in which true-cost pricing is not easy to achieve.
Hence, the rational choice assumption of environmental economics needs to be supplemented by an institutional dimension to
interpret responses to environmental taxes correctly.
Received: July 13, 2001 / Accepted: October 2, 2001 相似文献
7.
Satoru Fujita Kenzi Suzuki Yasuo Shibasaki Toshiaki Mori 《Journal of Material Cycles and Waste Management》2002,4(1):70-76
Hydrogarnet was synthesized hydrothermally below 200°C using molten slag obtained from municipal solid waste. For comparison,
it was also synthesized using pure-phase CaO–Al2O3–SiO2–H2O, as reported previously. The structural and textural properties of this material were investigated using various analytical
and spectroscopic techniques such as X-ray diffraction, X-ray fluorescence spectrometry, atomic absorption spectrometry (AAS),
thermogravimetry/differential thermal analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy.
The Cl− fixation ability of hydrogarnet was investigated in the temperature range 500–800°C in a fixed-bed flow reactor using a HCl
concentration (1000 p.p.m.v.) similar to that of incinerator exhaust gas. Under these experimental conditions, the hydrogarnet
was capable of reducing the HCl gas level to less than 1 p.p.m.v. Analysis of the spent catalyst revealed that the hydrogarnet
was being transformed into wadalite and CaCl2 at high temperatures. The elution test for chromium ions in hydrogarnet obtained from slag was also used, and it was found
that chromium ions were not eluted from hydrogarnet.
Received: January 27, 2001 / Accepted: October 11, 2001 相似文献
8.
Masahiro Shimada Takahiko Iida Kensuke Kawarada Yoshifumi Chiba Toshihiro Mamoto Takayuki Okayama 《Journal of Material Cycles and Waste Management》2000,2(2):100-108
In an earlier report, we presented a method for preparing activated carbon from waste newspaper as a way to recycle used paper
for a purpose other than producing raw material for paper-making. In this article, we consider the porous structure of the
activated carbon that affects its adsorption properties for various substances. The specific surface area of activated carbon
prepared from waste newspaper was 838 m2/g, the micropore volume was 0.368 ml/g, and the mesopore volume was 0.138 ml/g, which is about the same as commercially available
activated carbon. The activated carbon prepared from waste newspaper usually has a high content of ash, which makes little
contribution to the adsorption properties. In particular, as compared with reagent-activated carbon, the quantities of mesopores
with a pore radius of 3–25 nm and macropores with a pore radius of 25–250 nm were 8 and 14 times larger, respectively. Activated
carbon prepared from waste newspaper has a well-developed porous structure, particularly in the mesopore and macropore ranges.
Received: July 12, 1999 / Accepted: March 8, 2000 相似文献
9.
Holger Ecke Nourreddine Menad Anders Lagerkvist 《Journal of Material Cycles and Waste Management》2002,4(2):117-126
Dry scrubber residue from municipal solid waste incineration (MSWI) was characterized to identify critical inorganic pollutants
and to suggest a conceptual treatment method. The key methods used were thermal analysis, including thermogravimetry (TG)
and differential thermal analysis (DTA), pHstat titration, qualitative X-ray diffraction (XRD), scanning electron microscopy (SEM), chemical equilibrium calculations, and
statistics such as error propagation, principal component analysis (PCA), and empirical modeling based on factorial designs.
Based on EU directives, the major inorganic pollutants Cd, Cr, Pb, and Zn were found. In addition, the pH was too high. With
dry scrubber residue stabilization in mind, the impact of carbonation and hydration was assessed and judged to be encouraging.
In particular, chemical equilibrium calculations showed that carbonation has considerable potential to lower the pH and the
availability of Pb, Zn, and Cr. The impact of carbonation on the mobility of Cd was found to be small. During carbonation,
a metal-trapping calcium aluminosilicate hydrate (C–A–S–H) phase is also formed. Both processes together have the potential
to lead to a robust, reliable, and reasonable stabilization method for dry scrubber residue. However, to control these processes,
the decisive factors need to be identified and their effects need to be quantified. Ca, Cl, Na, and K might be abundant components
which would be mobile even after stabilization.
Received: September 11, 2001 / Accepted: December 6, 2001 相似文献
10.
We investigated the thermal properties and behavior of bromine on the thermal decomposition of paper-based phenolic laminate
wastes containing polybrominated flame retardants. The thermal properties of the phenolic laminate wastes were measured with
a thermogravimeter and a conduction-type scanning calorimeter (TG-CSC). The weight loss of the wastes on thermal decomposition
was mainly in three phases between 40°C and 600°C. The enthalpy (ΔH) of the thermal decomposition was 104 cal/g. The material balance of the decomposition components was measured with batch-type
thermal decomposition equipment. The ratios of carbon residue, liquid, and gas on decomposition at 800°C in a vacuum were
37 wt. %, 48 wt. %, and 15 wt. %, respectively. The bromine contents in the carbon residue and liquid were less than 0.02 wt.
% and 10 wt. %, respectively. These results are useful both in the carbonization process of these wastes and in the application
of carbon residue as carbon materials.
Received: August 11, 2000 / Accepted: March 7, 2001 相似文献
11.
Yukio Noma Sayuri Yamane Akiko Kida 《Journal of Material Cycles and Waste Management》2001,3(2):126-134
Adsorbable organic halides (AOX) and AOX formation potential (AOXFP) were investigated in 46 landfill lea-chates as potentially
toxic parameters. AOX in landfill leachate was within the range <10–2200 μg Cl/l, and AOXFP was within 51–15 000 μg Cl/l.
AOX and AOXFP correlated with chemical oxygen demand (COD). AOX discharge from closed landfills was generally lower than that
from operating landfills. The molar ratio of AOXFP/total organic carbon (TOC) suggested that organic compounds in a leachate
have a double bond every 15–190 carbons under the supposition that one chlorine would add to one double bond. The five landfills
discharging high-level AOXFP (>4000 μg Cl/l) were all landfills where sludge had been dumped. The removal efficiencies of
three parameters through leachate treatment processes were as follows: polychlorinated dibenzo-dioxins/dibenzo-furans (PCDDs/DFs)
> TOC > AOX. PCDDs/DFs were substantially removed at p.p.t. levels, while AOX was hardly removed at relatively low levels.
Received: February 14, 2000 / Accepted: January 9, 2001 相似文献
12.
In this study, we analyzed the sustainability and determinant factors of waste reduction through variable charging schemes.
We drew three main conclusions from the study. (1) Waste reduction was achieved by variable charging and was sustained over
an average of at least 10 years. The results regarding the sustainability of the price effect were inconclusive. (2) The main
factors contributing to the combustible waste reduction achieved through variable charging were two-tier pricing and the price
of waste bags. The effect of two-tier pricing programs was positive. (3) Waste paper recycling and variable charging reinforce
each other to promote waste reduction.
Received: September 3, 2001 / Accepted: January 13, 2002 相似文献
13.
This article describes the gasification of polyethylene–wood mixtures to form syngas (H2 and CO) with the aim of feedstock recycling via direct fermentation of syngas to ethanol. The aim was to determine the effects
of four process parameters on process properties that give insight into the efficiency of gasification in general, and particularly
into the optimum gasification conditions for the production of ethanol by fermentation of producer gas. Gasification experiments
(fluidized bed, 800°–950°C) were done under different conditions to optimize the composition of syngas suitable for fermentation
purposes. The data obtained were used for statistical analysis and modeling. In this way, the effect of each parameter on
the process properties was determined and the model was used to predict the optimum gasification conditions. The parameters
varied during the experiment were gasification temperature, equivalence ratio, the ratio of plastic to wood in the feed, and
the amount of steam added to the process. The response models obtained proved to be statistically significant in the experimental
domain. The optimum gasification conditions for maximization of carbon monoxide and hydrogen production were identified. The
conditions are: temperature 900°C, equivalence ratio 0.15, amount of plastic in the feed 0.11 g/g feed, and amount of steam
added 0.42 g/g feed. These optimum conditions are at the edge of the present experimental domain. The maximum combined CO
and H2 efficiency was 42%, and for the maximum yield of CO and H2 it is necessary to minimize the polyethylene content, minimize the added steam and the equivalence ratio, and maximize temperature. 相似文献
14.
Tohru Kamo Kanji Takaoka Junichiro Otomo Hiroshi Takahashi 《Journal of Material Cycles and Waste Management》2006,8(2):109-115
Steam gasification of dehydrochlorinated poly(vinyl chloride) (PVC) or activated carbon was carried out in the presence of
various alkali compounds at 3.0 MPa and 560°C–660°C in a batch reactor or in a semi-batch reactor with a flow of nitrogen
and steam. Hydrogen and sodium carbonate were the main products, and methane and carbon dioxide were the minor products. Yields
of hydrogen were high in the presence of sodium hydroxide and potassium hydroxide. The acceleration effect of the alkali compounds
on the gasification reaction was as follows: KOH > NaOH > Ca(OH)2 > Na2CO3. The rate of gasification increased with increasing partial steam pressure and NaOH/C molar ratio. However, the rate became
saturated at a molar ratio of NaOH/C greater than 2.0. 相似文献
15.
Motoyuki Sugano Akihiro Komatsu Masanori Yamamoto Mika Kumagai Takayuki Shimizu Katsumi Hirano Kiyoshi Mashimo 《Journal of Material Cycles and Waste Management》2009,11(1):27-31
Most landfilled plastic waste is a mixture or is in the form of composites with incombustible wastes such as glass, metals,
and ceramics. After hydrothermal treatment, including a steam-explosion process, the separation of mixed waste (MW) into organic
and inorganic substances becomes easy. However, the effect of hydrothermal pretreatment on the subsequent liquefaction of
organic substances from MW is not obvious. In this study, the effects on the liquefaction of polystyrene and high-density
polyethylene are discussed. Moreover, optimum conditions for the liquefaction of organic substances from hydrothermally treated
MW are identified. By means of this hydrothermal pretreatment, including the steam-explosion process, polystyrene and high-density
polyethylene can be significantly converted to oil by liquefaction at 300°–400°C. In comparison with liquefaction of hydrothermally
pretreated mixed waste (HMW) at 300°–400°C with a batch type reactor, the yield of oil increases significantly on liquefaction
using a semi-batch type reactor. It is considered that the radical chain and termination reactions among the radicals from
HMW were inhibited in the semi-batch type reactor. On liquefaction of HMW in a semi-batch reactor, the conversion of HMW to
oil was enhanced on increasing the liquefaction temperature to 350°C and the holding time to 60 min.
Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6 相似文献
16.
Kunichika Nakamiya Tohru Furuichi Kazuei Ishii 《Journal of Material Cycles and Waste Management》2002,4(2):127-134
This article reports the potential of denitrifying activated sludge to degrade highly chlorinated dioxins, especially from
a (landfill) leacheate treatment plant in Japan, and the isolation from this denitrifying activated sludge of a microorganism
able to degrade highly chlorinated dioxins. Using a 700-ml bioreactor, denitrifying activated sludge was cultivated under
denitrifying conditions by adding 2.0 ng of a mixture of 4- to 8-chlorinated dioxins from fly ash. The dioxin contents of
the sample, effluent, and medium before and after cultivation were measured by gas chromatography–mass spectrometry (GC–MS).
After 7 days cultivation, about 90% of added dioxins were lost (average percentage of isomer depletion). A dioxin-degrading
microorganism was isolated from the activated sludge. Lignin was added to the medium as a color indicator of aromatic compound
degradation, and the lignin-decolorizing microorganisms in the denitrifying activated sludge were screened. Some strains were
isolated, and one major isolated fungus, strain 622, decolorized lignin effectively. Strain 622 was identified as an Acremonium sp. from its morphological characteristics. It could decolorize lignin by 24% under paraffin-sealed anaerobic conditions.
After the cultivation of strain 622 with a 2 ng/ml mixture of 4- to 8-chlorinated dioxins for 1 day, 82% (average for individual
isomers) of the added 4- to 8-chlorinated dioxins had been degraded. Added octachlorodibenzo-p-dioxin (OCDD, 100 ng) was degraded under aerobic conditions after 8 h of incubation. During this process, heptachlorodibenzo-p-dioxin was produced and appeared to be a degradation product of OCDD. 1- or 2-hydroxydibenzo-p-dioxin from OCDD was also identified as the degradation product by GC–MS. These results indicated that OCDD was degraded
to the nonchlorinated dibenzo-p-dioxins through dechlorination by Acremonium sp. strain 622.
Received: October 12, 2001 / Accepted: March 11, 2002 相似文献
17.
Kuniyasu Kawaguchi Kazutada Miyakoshi Kiyoshi Momonoi 《Journal of Material Cycles and Waste Management》2002,4(2):102-110
It is important to investigate the pyrolysis processes of municipal solid waste (MSW) in the same way as for any mixture
comprised of multiple substances. In this article, a two-reaction model for a variety of MSW mixtures is proposed to predict
mass changes due to pyrolysis. In order to formulate the model based on pyrolysis kinetics, we conducted experiments to determine
the kinetic model parameters. By thermal analysis of the typical components of MSW, mass changes attributable to the pyrolysis
reaction were found at about 350°C for paper, 400°–500°C for plastics, and 200°–400°C for garbage (dry condition). Activation
energies were obtained by the Ozawa method based on the mass changes in pyrolysis. Thus, the pyrolysis behavior is formulated
as a function of temperature. Then the pyrolysis mass change of the mixture can be predicted by using a weighted sum of the
individual components. The model proved useful in experiments with real waste (refuse-derived fuels). Furthermore, the weight
yields (pyrolysis gas, tars, solid residues) of the mixture can be calculated by their additive property after measuring the
mass balance of each component.
Received: May 11, 2001 / Accepted: November 16, 2001 相似文献
18.
Measurements of aerosol size-separated number concentrations were performed in March 2001 on the Tama Hills of Japan, located
near regions of heavy industry. The concentrations of particles larger than 1.0 μ m in diameter dramatically increased during
the Kosa phenomena on 6–8 and 18–24 March. The number concentrations of coarse particles (> 3.0 μm) showed distinct diurnal
variations, especially during the Kosa events. Fine particles smaller than 0.5 μm increased when the relative humidity was
high and the wind speed was low. On the other hand, the coarse particles concentrations were well correlated with wind speed
and temperature. The dry deposition velocity of the coarse particles at the forest canopy was estimated from the nighttime
decrease in the number concentrations. 相似文献
19.
Kotaro Minomo Nobutoshi Ohtsuka Kiyoshi Nojiri Yasundo Kurata Masafumi Karaushi Yugo Isobe 《Journal of Material Cycles and Waste Management》2009,11(1):73-81
In this study, we propose an analytical method to determine the fourteen of azaarenes present in flue gas samples collected
according to Japanese Industrial Standard K 0311, which designates the method for the determination of dioxins in flue gas.
Azaarenes can be analyzed using the acidic water phase after shaking extraction with dichloromethane, which is unnecessary
for dioxin analysis. Flue gas samples were obtained from 24 waste incinerators in Japan, and azaarenes were detected in all
the flue gas samples (0.21–3800 μg/m3
N). The most abundant of the detected compounds were quinoline and isoquinoline. The concentration of azaarenes had a tendency
to increase with that of polychlorinated dibenzo-p-dioxins and dibenzofurans. The isomer distribution of heptachloro-dibenzofurans (HpCDFs) was calculated using the computed
Gibbs energy of formation (ΔG
f
) obtained by the semiempirical molecular orbital method at various temperatures. The calculated isomer distribution was fitted
to the measured value of HpCDFs. It seems that the temperature obtained from the fitting calculations is an indicator of the
cooling capacity of the combustion gas in an incinerator. The computed ΔG
f
also explained the measured isomer distributions of azaarenes. It is suggested that the isomer distribution of azaarenes
in the combustion process is thermodynamically controlled.
This work was presented in part at the International Conference on Combustion, Incineration/Pyrolysis, and Emission Control,
2006, Kyoto 相似文献
20.
Zhao Rongfang Ye Shufeng Xie Yusheng Chen Yunfa 《Journal of Material Cycles and Waste Management》2007,9(1):7-14
A new way to implement the simultaneous reutilization of solid waste, the desulfurization of coke oven gas (COG), and even
the desulfurization of coke by the co-coking of coking coal (CC) and waste plastic (WP) blended with a sorbent is proposed;
the evolution of H2S and the removal efficiency of H2S from COG during the co-coking process were investigated in a lab-scale cylindrical reactor. The experimental results indicated
that for the coking of CC blended with ZnO, Fe2O3, or blast furnace dust (BFD) as a sorbent, the instantaneous concentration of H2S in COG was lower than 500 mg/m3 (which meets the technical specification requirement of the Chinese Cleaner Production Standard–Coking Industry, HJ/T 126-2003)
when the molar ratio between the key component of the sorbent and the volatile S in CC or the CC/WP blend, n
Zn+Fe/n
S, was about 1.2 for ZnO and Fe2O3, but not for BFD under the same conditions, suggesting that ZnO and Fe2O3 are promising sorbents, but that BFD must be treated chemical or thermally before being used as a sorbent because of the
size and complicated nature of the influence of its phase/chemical composition on its desulfurization ability. However, for
the co-coking of CC and WP blended with ZnO as a sorbent, n
Zn+Fe/n
S must increase to 1.4 and 1.7 for 100/2 and 100/5 blends of CC/WP, respectively, to ensure a satisfactory efficiency for H2S removal from COG.
Part of this paper was presented at the International Symposium on EcoTopia Science 2005 (ISET05), Aug 8–9, 2005, Chikusa-ku,
Nagoya, Japan 相似文献