Utilization of municipal solid waste incineration ash in Portland cement clinker

Municipal solid waste incineration (MSWI) ash is used in part as raw materials for cement clinker production by taking advantage of the high contents of SiO₂, Al₂O₃, and CaO. It is necessary for environmental reasons to establish a material utilization system for the incineration waste ash residue instead of disposing these ashes into landfill. The aim of this paper is to study the feasibility of replacing clinker raw materials by waste ash residue for cement clinker production. MSWI bottom ash and MSWI fly ash are the main types of ashes being evaluated. The ashes were mixed into raw mixture with different portions of ash residue to produce cement clinker in a laboratory furnace at approximately 1400°C. X-ray diffraction and X-ray florescence techniques were used to analyze the phase chemistry and chemical composition of clinkers in order to compare these ash-based clinkers with commercial Portland cement clinker.     

A system tradeoff model for processing options for household plastic waste

With the "Containers and Packaging Recycling Law", Japan has shown a firm conviction towards the promotion of recycling. Waste can be "recycled", i.e. resource value of waste material can be recovered, in many ways, from material recycling to energy recycling. Alternatively, waste can be reduced or disposed of in landfills. A system tradeoff model is developed from component process technology models of six different recycling and disposal options for household plastic waste processing: plastic pellet production, refuse derived fuel production, oil production, waste incineration to produce electricity, use of waste plastic as a coke substitute, and incineration for volume reduction. These technologies are compared with the case where all waste plastic is land filled. Models based on plant data, laboratory experiments, and theoretical considerations of scale effects and mass balances are developed to calculate the cost, energy consumption, CO₂ emission, and land fill occupancy. The models also calculate the valued products of each technology and convert them into cost, energy, CO₂, and landfill occupancy using life cycle inventory data. These values are subtracted from the outputs of the waste processing models to obtain overall performances for each technology. The overall tradeoff system model is then used to evaluate several scenarios of plastic recycling and disposal technologies in Tokyo. Electronic Publication     

Evaluation of meat and bone meal combustion residue as lead immobilizing material for in situ remediation of polluted aqueous solutions and soils: "chemical and ecotoxicological studies"

As a result of bovine spongiform encephalopathy (BSE) crisis, meat and bone meal (MBM) production can no longer be used to feed cattle and must be safely disposed of or transformed. MBM specific incineration remains an alternative that could offer the opportunity to achieve both thermal valorization and solid waste recovery as ashes are calcium phosphate-rich material. The aim of this work is to evaluate ashes efficiency for in situ remediation of lead-contaminated aqueous solutions and soils, and to assess the bioavailability of lead using two biological models, amphibian Xenopus laevis larvae and Nicotiana tabaccum tobacco plant. With the amphibian model, no toxic or genotoxic effects of ashes are observed with concentrations from 0.1 to 5 g of ashes/L. If toxic and genotoxic effects of lead appear at concentration higher than 1 mg Pb/L (1 ppm), addition of only 100 mg of ashes/L neutralizes lead toxicity even with lead concentration up to 10 ppm. Chemical investigations (kinetics and X-ray diffraction (XRD) analysis) reveals that lead is quickly immobilized as pyromorphite [Pb10(PO4)6(OH)2] and lead carbonate dihydrate [PbCO(3).2H2O]. Tobacco experiments are realized on contaminated soils with 50, 100, 2000 and 10000 ppm of lead with and without ashes amendment (35.3g ashes/kg of soil). Tobacco measurements show that plant elongation is bigger in an ashes-amended soil contaminated with 10000 ppm of lead than on the reference soil alone. Tobacco model points out that ashes present two beneficial actions as they do not only neutralize lead toxicity but also act as a fertilizer.     

Numerical simulation of dam construction using low-CO<Subscript>2</Subscript>-emission concrete

Cement production gives rise to CO₂ emissions generated by the calcination of CaCO₃ and by the combustion of fossil fuels, being responsible for about 5% of the global CO₂ emissions. These emissions can be substantially reduced if cement replacement materials are used. In this paper two residual ashes that can be used as mineral additions are considered: sugar cane bagasse ash and rice husk ash. A case study of the construction of a dam with a blended material composed by cement and these two ashes is presented, indicating the potentiality of its use for civil engineering applications. The analyses were performed using experimental and numerical tools developed on the basis of a thermo-chemo-mechanical model. This model considers the coupling, within the theory of thermodynamics, of the several phenomena that intervene in the hydration process, namely, exothermicity, thermo-activation, chemo-plasticity, evolution of thermal and mechanical properties with the hydration reaction, which includes creep and relaxation.     

New chickens and new eggs——New catalytic materials for alternative fuels and chemical feedstock

The on-going depletion of the oil reserves leads to the needs for development of sustainable and renewable energies. Between fossil and solar eras,low carbon natural gas and clean coal become the most crucial intermediate alternatives as energy source and feedstock to produce chemicals.In meantime,lignocellulosic biomass will play the role as fuel or as raw material,especially for the future decades.This is of ultimate importance for the countries with increased demands for energy in a portable form and for synthetic materials,such as China. New catalytic materials are at the heart in the processes(existing and innovative)to converting natural gas or coal,the nonportable or non-pumpable energy carriers,to liquid form,and to upgrading less valuable to more value-added chemicals for a particular market requirement.In many instances,innovation of a new catalytic material makes a new process from dream to reality,and in the other cases,the need for a new process catalyzes the research for a new catalytic material. The process and material("chickens and eggs")interplay propels the recent advances in hydrogen fuel,GTL,CTL,CTC,SNG and BTL technologies.In this growing market,Siid-Chemie has not only strengthened its market presence,but also consolidated its position as the worldwide technology alytic materials in the new chemical processes,such as ShiftMax(R),ActiSorb(R),AmoMax(R),MegaMax(R),DME-1(R),FAMax(R),and MTPro-1(R).Siid-Chemie commits to provide the best performing tailored catalytic materials to the matching processes.     

Alkali-activation potential of biomass-coal co-fired fly ash

Co-fired fly ash, derived from the co-combustion of coal and biomass, is examined as a potential precursor for geopolymers. Compared to a coal fly ash, two co-fired fly ashes have a lower vitreous content and higher carbon content, primarily due to differing combustion processing variables. As a result, binders produced with these co-fired fly ashes have reduced reaction potential. Nevertheless, compressive strengths are generally highest for all ashes activated with solutions with a molar ratio of SiO₂/(Na₂O + K₂O) = 1, and these mixes reach the highest extent of reaction among those studied. Activation with sodium hydroxide solution forms zeolitic phases for all ashes. The thermal and dilatometric behavior of the coal and co-fired fly ash geopolymers is similar between equivalent mix designs. These results indicate that co-fired fly ashes can be viably used to form alkali-activated geopolymers, which is a new beneficial end-use for these emerging waste materials.     

Characteristics of industrial and laboratory meat and bone meal ashes and their potential applications

This paper reports the characterization of four meat and bone meal (MBM) ashes obtained from specific incineration (laboratory) and from co-incineration (industrial process). Three out of the four MBM ashes were mainly composed of calcium phosphates (hydroxyapatite and whitlockite). Their compositions (major and trace) were in the range for natural phosphate rocks. Trace element contents, including heavy metals, were below 0.6% and industrial ashes contained much more heavy metals than laboratory ash. The amounts of leached elements were low, especially for laboratory ash. According to the European classification of waste to be landfilled, the laboratory ash can be classified as an inert waste. Two industrial ashes are mostly inert. Only one ash is highly leachable and needs a stabilization treatment to be classified at least in the category of hazardous waste. It seems, from these results, that possibilities other than landfilling could be considered to give economic value to these ashes.     

Determination of the level of a substance in a production vessel at high temperature

A radiofrequency method is considered for determining the level of a substance in a vessel at about 1000°C or more that is used in particular for indicating the level of timber plant production waste (wooden fuel) in furnaces of heat generating units. Construction features of these radiofrequency sensors based on sections of long lines are described in detail. __________ Translated from Izmeritel'naya Tekhnika, No. 8. pp. 29–30, August, 2008.     

What we can't learn from nature

When attempting to design bio-inspired materials and structures, it is important to remember that Nature employs some strategies for optimising the use of load-bearing materials which we, as engineers, cannot replicate. A material in a biological structure, such as a bone or plant stem, experiences stresses which are higher than would be allowed in an engineering structure, even if we were using exactly the same material. There are several reasons for this: biological materials are subject to continuous inspection and repair; they are constructed in more optimal ways, especially in respect to fibre orientations, and they are allowed to operate at higher failure rates. In the present paper I discuss four particular examples of Nature's strategies and, in each case, I try to quantify their effect for the case of cortical bone. The overall conclusion is that, thanks to these four little tricks, Nature is able to operate bone at a stress which is about 17 times greater than the stress at which it could be used in an engineering component. Considering how a typical bone is loaded, this implies an increase in weight of about a factor of 10.     

An evaluation of the mechanical performance of extruded wheat starch loose fill

During the distribution process, products are continuously exposed to dynamic forces resulting from vehicle vibrations as well as drops and shocks from various types of handling. In order to reduce the adverse effects of such loads, protective packaging or cushioning materials are used. Engineered packaging materials are generally petroleum based (plastics) and present significant environmental concerns after their disposal. The use of environmentally friendly, bio‐compostable, alternatives is a logical development; however, if the salient protective characteristics of these materials are not well established, their use may lead to greater losses and a larger environmental impact through product loss. This paper introduces a comprehensive approach for the mechanical characterisation of alternative cushioning materials, which includes the effects of environmental conditions. The procedure is used to compare the performance of loose fill starch beads with a commonly used engineering cushioning material, namely medium density, closed cell polyethylene. The results show that the starch beads can offer a viable alternative to the engineered cushioning materials as they provide reasonable overall cushioning character, albeit over a narrower stress range when compared with the polyethylene cushions. The loose fill was also shown to perform in terms of vibration damping and resistance to sustained dynamic loads for low static stress levels.     

Energy recovery from heavy ASR by co-incineration in a fluidized bed combustor

Automotive shredder residue (ASR) is a heterogeneous waste stream with varying particle size and elemental composition. Owing to its complexity and hazardous characteristics, landfilling of ASR is still a common practice. Nevertheless, incineration with energy recovery of certain ASR fractions (Waste-to-Energy, WtE) emerges as an interesting alternative. In a full scale experiment, a waste mix of 25 % heavy ASR, 25 % refuse derived fuel (RDF), and 50 % waste water treatment (WWT) sludge was incinerated in the SLECO fluidized bed combustor (FBC) at the Indaver site in Antwerp, Belgium. Input and output streams were sampled and analyzed to make an inventory of the most important pollutants and toxics. The inventory was further used to determine the environmental impact. Results are compared to those of two other scenarios: incineration of the usual waste feed (70 % RDF and 30 % WWT sludge) and co-incineration of 39 % ASR with 61 % WWT sludge. It can be concluded that co-incineration of heavy ASR in an existing FBC is a valid and clean technology to increase current reuse and recovery rates. In the considered FBC, 27 % of the energetic value of ASR can be recovered, while all emissions remain well below regulatory limits and only 12.6 % of the heavy ASR needs to be landfilled. The proportion of ASR in the input waste mix is however limited by the heavy metal concentration in the ASR and the generated ashes.     

Modelling the Material Flow and Web Tension in the Vertical Form–Fill–Seal Packaging Process

Vertical form–fill–seal (VFFS) machines are widely used to form bags for packaging products such as confectionary and snack food. One critical component of the machine is the forming shoulder, which needs to manipulate, without damage, the packaging material from a flat state into a tube. Some models of the geometry of the shoulder are available and have been used to help with its design and manufacture. However, there currently exists no theoretical basis for determining the geometry of the forming shoulder needed to process particular packaging materials. This paper investigates the application of Euler's theory for material flow around cylinders to the case of forming shoulders used in vertical form–fill–seal systems. It is shown that the theory is indeed applicable, and an inequality relation between the measured coefficient of friction of the material and the forming shoulder parameters is established. It is further shown how this can be used to direct the design of a forming shoulder for a particular application. Copyright © 2011 John Wiley & Sons, Ltd.     

去除光刻胶的新干法工艺

除去干刻或高剂量等离子注入后的光刻胶，一般是采用化学溶剂和酸类等湿刻法，以前有时采用干燥氧的等离子灰化法，然而成本高，具有危险性和污染性的化学湿刻法直接造成了环境污染，使得全球气候变暖，能源的大量消耗，地下水受到污染等等，一种新的干式去胶并且处理后可用去离子水DI清洗残留物的工艺方法（ENVIRO）已经在半导体芯片厂被成功地使用了12个多月。对于产量10000片／周的芯片厂，相对于化学湿刻法一年可以节省5百万美元溶剂消耗。     

堆石料非饱和湿化变形特性试验研究

降雨会在土石坝体中导致非饱和入渗过程,并可发生显著的湿化变形,从而对坝体的应力变形性状产生重要的影响。该文采用模拟降雨入渗的方法控制堆石体的湿化饱和度,进行了侧限压缩条件下的非饱和湿化试验,研究和分析了堆石体的非饱和入渗过程和不同饱和度情况下的湿化变形特性。试验分析结果表明,只有小孔隙吸附水才是有效湿化含水量,堆石体的湿化变形主要发生在小含水量湿化阶段,而大孔隙自由水为无效含水量,对堆石料湿化变形的影响不大;对所研究的糯扎渡弱风化花岗岩堆石料,其有效湿化饱和度小于25。5%。     

Comparison of various loose fill cushioning materials based on protective and environmental performance

This paper compares various loose fill packaging materials based on the amount of material required for a given level of protection. A methodology developed to evaluate and compare package cushioning materials on the basis of environmental concerns relative to disposal and recycling is used to compare seven different loose fill materials. The materials compared include recycled expanded polystyrene (EPS), starch and paper based materials, wood shavings and popcorn. The shock level G was related to the amount of cushion material needed both by weight and by volume. The results show that starch-based loose fill materials (Naturpack and Eco-Foam) and Fiberflow showed the best protective performance and minimum material utilization by volume. 100% recycled EPS showed the best performance in terms of percent weight utilization. Other materials tested, like popcorn and wood shavings, showed poor material utilization.     

Thermo-analysis of fly ash and other particulate materials for predicting stable filtration of hot gases

Ceramic filters used to remove particles from hot gases were tested at temperatures between 200 and 850°C with redispersed combustion ashes from biomass, two (German) coals, municipal waste as well as mixtures of ash with sorbent particles. The duration of the first 50 filtration cycles was used to derive a measure of operating stability. For the same ash materials, data on thermal expansion (by dilatometry), weight loss (by thermo-gravimetric analysis) and relative heat flux (by differential scanning calorimetry) were obtained. Pure powders of NaHCO₃, Ca(OH)_2, CaCO₃ and Na₂SO₄ were tested for comparison. Particle size and chemical composition information for the ashes was also obtained. Filtration behavior correlated with thermo-analytical data for the various materials, in that temperature regions of pronounced physical or chemical changes within the powder samples were generally good indicators of instable filter operation. Materials of complex composition such as ashes and in some cases also the pure powders had more than one region of instability, with ‘metastable’ filter operation possible in between. A chart was developed to attempt the prediction of mixtures of ashes with pure powders.     

Evaluation of hazardous waste incineration in lime kiln: Rockwell lime company

During a one-week test burn, hazardous waste was used as supplemental fuel and co-fired with petroleum coke in a lime kiln in eastern Wisconsin. Detailed sampling and analysis was conducted on the stack gas for principal organic hazardous constituents (POHCs), particulates, particulate metals, HCl, SO₂, NO_x, CO, and THC and on process streams for metals and chlorine. POHCs were also analyzed in the waste fuel. Sampling was conducted during three baseline and five waste fuel test burn days. Results show average destruction and removal efficiences (DREs) greater than 99.99% for each POHC and little change in pollutant emissions from baseline to waste fuel test conditons. In addtion, material balance results show that 95% of chlorine enters the process from the limestone fed and the chlorine exits the kiln in the baghouse dust and lime product at 61% and 38%, respectively.     

The quantitative estimation of silica in rice husk ash by titrimetric method: A case study for uncertainty calculation

Silicon is an essential element found in cereals, fruits, vegetables pasta, rice, etc. Rice husk ash is one of the most silica rich raw materials after complete combustion among the family of agro wastes. For the preparation of pure activated silica rice husk are now widely used as raw material. Rice husk ashes are now used by various industries for different applications due to its important properties. The exact quantity of silica in the rice husk ash is therefore essential to know before further research. Keeping these facts an attempt has been made to determine the silica content by titrimetric method followed by quantification of uncertainty budget in four different variety of rice husk ash. The major sources of uncertainty in the measurement have been identified as contributions from repeatability, standardization of sodium hydroxide, titration, weight of the sample taken, volume measurement by volumetric flask, burette, pipette, weighing balance etc. All major sources of uncertainty have been identified and combined following the EURACHEM guidelines.     

液体介质处理对纳米隔热材料细观结构的影响

为研究液体介质处理对纳米隔热材料细观结构的影响,并掌握材料结构对毛细管力的承受性,将纳米隔热材料分别在无水乙醇和去离子水中进行了浸泡和常温常压干燥处理。采用热导率测试结合SEM、N₂吸附-脱附、光学显微镜等对材料处理前后的细观结构进行了表征,并以Kaganer双孔模型对气相热导率随环境气压的变化进行了描述。研究结果表明,材料固体骨架颗粒尺度和孔隙结构均不受无水乙醇处理的影响;去离子水处理后的材料固体骨架颗粒尺度虽未改变,但颗粒之间的接触面积有所增大,并且孔隙结构发生了两极分化,一部分变大,另一部分变小;处理前以及无水乙醇处理后,材料的孔隙结构均可以等效为70 nm和300 nm两种尺度的典型孔隙,占比分别约为81%和19%,而去离子水处理后的材料孔隙结构需要等效为30 nm和60 μm两种尺度的典型孔隙,占比分别约为58%和42%。      

Models for recycling electronics end-of-life products

Increasing environmental concerns about the disposal of mass produced products have resulted in efforts to take back end-of-life consumer products. Legislation aimed at forcing manufacturers to take back electronics products at the end of their useful lives has either been adopted or is impending in many countries. This, along with shrinking landfill capacity and the reluctance of communities to open new waste sinks underscores the importance of developing methods and models for the management of end-of-life materials and products. This paper reports a study of the reverse channels for recycling of electronics products. The economics of electronics recycling are modeled from the viewpoints of the generators, recyclers, and material processors separately. A variety of mathematical programming models, representative of the many ways in which the recycling industry currently operates, have been proposed along with numerical illustrations. Models integrating disassembly and material recovery decisions are also presented. These models can be used by recyclers and processors for optimizing recycling operations and thus contribute towards the economic sustainability of electronics recycling.