Filtern
Dokumenttyp
- Zeitschriftenartikel (7)
- Beitrag zu einem Tagungsband (6)
- Beitrag zu einem Sammelband (1)
- Vortrag (1)
- Sonstiges (1)
Sprache
- Englisch (16) (entfernen)
Schlagworte
- Bottom ash (4)
- Secondary raw materials (3)
- Treatment train (3)
- Bottom ash (BA) (2)
- Copper (2)
- Density separation (2)
- Direct material input (2)
- Municipal solid waste incineration (MSWI) (2)
- Recyclable material (2)
- Recycling technology (2)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (1)
The industrial sector of incinerator bottom ash (IBA) treatment from municipal solid waste (MSW) is currently changing. Since established techniques are not yet suitable for fine grain sizes, pollutants are enriched and the effort for the treatment increases exponentially it is nowadays generally landfilled. Innovative treatment trains for the recovery of minerals and metals from the fine fraction will be presented and discussed. In fresh IBA this fraction < 2 mm amounts to around 25 % and contains different precious elemental and chemically bonded metals, especially copper. All copper species have higher densities compared to the bulk minerals. Investigations for the enrichment of copper carried out with a centrifugal classifier will be introduced.
The reliable characterization of subsurface contamination of spatially extended contaminated sites is a challenging task, especially with an unknown history of land use. Conventional technologies often fail due to temporal and financial constraints and thus hinder the redevelopment of abandoned areas in particular. Here we compare two site screening techniques that can be applied quickly at relatively low cost, namely Direct Push (DP)-based groundwater sampling and tree core sampling. The effectiveness of both methods is compared for a rural megasite contaminated with chlorinated hydrocarbons. Unexpected pollution hot spots could be identified using both of these methods, while tree coring even enabled the delineation of the contaminant plume flowing into an adjacent wetland inaccessible for DP units. Both methods showed a good agreement in revealing the spatial pattern of the contamination. The correlation between groundwater concentrations and equivalent concentrations in wood was linear and highly significant for trichloroethene. Correlation was less obvious for its metabolite cis-dichloroethene, but still significant. As outcome of our study we recommend tree coring and for initial screening in combination with a DP sampling to retrieve quantitative data on groundwater pollutants in order to assess the contamination situation of a non- or only partly investigated site. The subsequent placement of monitoring wells for long-term monitoring of contamination levels is recommended. A combination of methods would achieve more relevant information at comparable or possibly even lower efforts in comparison to a conventional site investigation.
In 2011, the German Association of Engineers (VDI) started working on a set of guidelines dealing with the improvement of resource efficiency. These guidelines represent a framework that defines resource efficiency and outlines proposals for the producing industry. A special guideline for small and medium-sized enterprises (SMEs) is included as well as guidelines on methodologies for evaluating resource use indicators, such as the cumulative raw material demand of products and production systems. The work on resource use indicators is still in progress. The evaluation of raw materials expenditure will include water, soil and land use. The model will include the availability of raw materials (criticality). Improving resource efficiency at the end-of-life stage is illustrated in this paper by the example of materials recovery from waste, here from residues out of municipal solid waste incineration (MSWI). With mechanical treatment valuable materials like ferrous and non-ferrous metals and secondary construction material can be extracted from MSWI bottom ash. The potential contribution on the resource efficiency is discussed.
Bottom ash from municipal solid waste incineration (MSWI) consists of eiemental metals in considerable amounts. The fine fraction < 4 mm additionally contains chemically bound metals (oxides, carbonates, Silicates). Separation prospects with techniques as in ore processing (flotation, density separation, bioleaching, hydrothermal solution) are discussed. During alteration after wet extraction mineral material with hydraulic properties form coatings on almost all particles of the bottom ash and complicate separation procedures. ln addition bottom ash from MSWI is a heterogeneaus material. For sufficient enrichment different concerted treatment steps seemed to be essential associated with an uncertainty of economic viability. The utilisation of metal compounds present in bottom ash as secondary raw material depends on the energy- and resource-efficiency of the enrichment processes. Therefore energy and material flow considerations are presented.
Direct and indirect effects (DIERec) of the recovery of secondary resources are in the range of 500 million tons per year in Germany; energy savings are 1.4 million TJ. These savings are between 10 and 20% of the total. The effects of materials recovery exceed those of energy recovery by far except for secondary plastic material, where DIERec from energy recovery is higher by factor of 2.7. Untapped potential for the recovery of secondary resources exists in the fine fraction of bottom ash from municipal solid waste incineration, mainly Cu and precious metals, and in urban mining.
Raw material supply is essential for all industrial activities. The use of secondary raw material gains more importance since ore grade in primary production is decreasing. Meanwhile urban stock contains considerable amounts of various elements. Photovoltaic (PV) generating systems are part of the urban stock and recycling technologies for PV thin film modules with CdTe as semiconductor are needed because cadmium could cause hazardous environmental impact and tellurium is a scarce element where future supply might be constrained. The paper describes a sequence of mechanical processing techniques for end-of-life PV thin film modules consisting of sandblasting and flotation. Separation of the semiconductor material from the glass surface was possible, however, enrichment and yield of valuables in the flotation step were non-satisfying. Nevertheless, recovery of valuable metals from urban stock is a viable method for the extension of the availability of limited natural resources.
Bottom ash from municipal solid waste incineration (MSWI) consists of elemental metals in considerable amounts. The fine fraction < 4 mm additionally contains chemically bound metals (oxides, carbonates, silicates). Separation prospects with techniques as in ore processing (flotation, density separation, bioleaching, hydrothermal solution) are discussed. During alteration after wet extraction mineral material with hydraulic properties form coatings on almost all particles of the bottom ash and complicate separation procedures. In addition bottom ash from MSWI is a heterogeneous material. For sufficient enrichment different concerted treatment steps seemed to be essential associated with an uncertainty of economic viability. The utilisation of metal compounds present in bottom ash as secondary raw material depends on the energy- and resource-efficiency of the enrichment processes. Therefore energy and material flow considerations are presented.
Small grain sizes of municipal solid waste incineration (MSWI) bottom ash (BA) contain elemental and chemically bonded metals in appreciable amounts, especially copper. As different copper species have in general a higher density compared to the prevalent minerals, processes for density separation seemed to be favorable for the recovery of copper. Investigations with a centrifugal classifier were therefore carried out with BA from MWSI which have been used for a few years as the covering material for a landfill. The results show an appreciable enrichment of the precious copper. The concentrates contained up to 60 mg/kg copper in the dry weight (DW) (in general about 30 – 40 mg/kg DW) with enrichment factors of around 20 and a copper recovery of up to 50 % (in general around 20 %). A test series in order to evaluate the potential benefit for sequential processing illustrate the low efficiency for a further processing of the tailings.
Small grain size fractions of municipal solid waste incineration (MSWI) bottom ash (BA) contain elemental and chemically bonded metals in appreciable amounts, especially copper. Investigations with a centrifugal concentrator were carried out using samples, which had been treated with different impact devices. Partly the impacts of single devices were visible in outlines, but mostly the surfaces of the metals were still covered with mineral residues. To generate copper rich fractions, parameters of the separation process should ensure mass yields <2%, best between 0.5 and 1%. The density of the concentrates is then generally >3.2 g/cm3. Best results were achieved with material from a special treatment train which is adapted to grain sizes <2 mm. Reliable copper contents between 20 and 40% (single runs >50%) could be realised.
However, considering the required mass yields, referred to this subset only 150–170 g copper would be recovered from 1 Mg MSWI BA. Furthermore, this copper is only in parts present in elemental form. A
dependable added value of such treatment step seems to be given only, if that enables a recycling of the mineral aggregates (tailings) in parallel to avoid landfill costs.
The industrial sector of bottom ash (BA) treatment from municipal solid waste incineration (MSWI) in Germany is currently changing. In order to increase the recovery rates of metals or to achieve a higher quality of mineral aggregates derived from BA, new procedures have been either implemented to existing plants or completely new treatment plants have been built recently. Three treatment trains, which are designated as entire sequences of selected processing techniques of BA, are introduced and compared. One treatment train is mainly characterized by usage of a high speed rotation accelerator whereas another is operating completely without crushing. In the third treatment train the BA is processed wet directly after incineration. The consequences for recovered metal fractions and the constitution of remaining mineral aggregates are discussed in the context of legislative and economical frameworks. Today the recycling or disposal options of mineral residues still have a high influence on the configuration and the operation mode of the treatment trains of BA despite of the high value of recovered metals.
The fine fraction of bottom ash from municipal solid waste incineration is characterized of both a high pollution and relevant resource potential. Methods for studying the environmental behaviour of solid residues are leaching tests. Various leaching test are adopted all over Europe with liquid to solid ratio of 2 or 10 l/kg. In Germany three different leaching Tests are valid with the commencement of the draft of the ordinance of reuse of mineral waste as alternative building ordinance. Comparing two batch tests, only the concentration for chloride is comparable. To evaluate the metal resource potential in the sand fraction wet chemical Methods have been applied. Methodical problems were caused mainly by the material heterogeneity and especially for precious metals due to their low concentration around 1 mg/kg. Other Methods have been available, but hardly applicable.
Bottom ash from municipal solid waste incineration (MSWI) consists of elemental metals in considerable amounts. The exergy of bottom ash was calculated to be some 100 kJ/mol, mainly as a result of the presence of elemental Fe and Al. From this it can be shown that the recovery of elemental metals Cu, Al and Fe is beneficial. The fine fraction <4 mm additionally contains chemically bound metals (oxides, carbonates, silicates). Separation prospects with techniques as in ore processing (flotation, density separation, bioleaching, hydrothermal solution) are discussed. Although the concentration of Cu compounds in bottom ash is in the range of today’s exploited ores the economic viability of the recovery of metal compounds is uncertain. For sufficient enrichment different concerted treatment steps are required.
The industrial sector of bottom ash (BA) treatment from municipal solid waste incineration (MSWI) in Germany is currently changing. In order to increase the recovery rates of metals or to achieve a higher quality of mineral aggregates derived from BA, new procedures have been either implemented to existing plants or completely new treatment plants have been built recently. Three treatment trains, which are designated as entire sequences of selected processing techniques of BA, are introduced and compared. One treatment train is mainly characterized by usage of a high speed rotation accelerator whereas another is operating completely without crushing. In the third treatment train the BA is processed wet directly after incineration. The consequences for recovered metal fractions and the constitution of remaining mineral aggregates are discussed in the context of legislative and economical frameworks. Today the recycling or disposal options of mineral residues still have a high influence on the configuration and the operation mode of the treatment trains of BA despite of the high value of recovered metals.
Improving resource efficiency at the end-of-life stage is illustrated in this paper by the example of materials recovery from waste, here from residues out of municipal solid waste incineration (MSWI). With mechanical treatment valuable materials like ferrous and non-ferrous metals and secondary construction material can be extracted from MSWI bottom ash. The potential contribution on the resource efficiency will be discussed.
In Germany, the direct material input (DMI) was 1727 million tons in the year 2014. This figure would be even higher by more than 14 % if no secondary materials were already used in industrial production. For example, production of secondary Cu is advantageous due to lower energy consumption and conservation of scarce natural resources. The presentation will discuss pathways to increase the use of secondary raw materials to foster a circular economy with a focus on waste treatment processes.