国外建材产业发展循环经济简况

第二次世界大战之后,特别是从20世纪50年代开始,欧洲各国、日本及美国等国家以住宅建设为主的建筑产业化快速发展,极大地激活并快速推进了建材生产的产业化发展。但是,建材产业的迅猛发展又带来了两个十分突出的问题：一是极大地消耗了煤炭、电力、石灰石、土地等不可再生资源;二是产生大量的废气、废料、废渣、废水,对大气环境和自然环境造成严重的污染。为了应对日益严重的资源危机与环境危机,从20世纪70年代,开始发展以“减量化、再利用、再循环”为核心的循环经济,发达国家建材产业纷纷引入循环经济理念,在“减量化、再利用、资源化”方面取得显著成效。     

建材产业发展循环经济的任务目标与措施

从多方面论述了建材产业发展循环经济的任务、目标、技术路线及措施。指出在循环经济之业链中,建材产业将成为资源减量化、再利用、再循环途径最多和潜力最大的产业之一,建材产业发展循环经济,既可实现自身的可持续发展,又可促进和带动其他行业循环经济的发展。     

我国冶金渣开发利用产业慨况及发展前景

全面分析了我国冶金渣开发利用产业的发展状况和存在问题,提出行业未来的发展战略,指出我国冶金渣开发利用处于起步阶段,与发达国家相比还有很大差距,具有巨大的发展潜力和良好的投资环境。     

建筑材料再循环利用价值研究

绿色建筑材料及产品的再循环利用价值的确定似乎是一件比较简单的事情,但在绿色建筑评估体系中来具体确定其再循环价值却是非常困难的.对建筑评价体系中的建筑材料再循环价值进行初步研究和计算,该计算过程考虑了建筑材料选择、建筑结构、建筑施工、建筑拆除技术以及回收频率等,因其计算结果含有能量因素,可作为建筑材料再循环价值的计算方法.     

Solidification/stabilisation of arsenic bearing fly ash from the metallurgical industry. Immobilisation mechanism of arsenic

When a fly ash waste material from a copper refining process containing large amounts of As2O3 is solidified using cement and lime, the arsenic concentration in the leachate can be lowered to ca. 5 mg/l in a saturated solution of Ca(OH)2. It is shown that the decrease of the concentration in the leachate, mainly of As(III), is due to the formation of insoluble CaHAsO3 in the leachate in the presence of Ca(OH)2. This method is compared with a method whereby use is made of oxidation of the waste before solidification to oxidise As(III) to As(V) using H2O2. The arsenic concentration in the leachate of the extraction test of an oxidised S/S sample was lowered to ca. 0.5 mg/l, a factor of 10 below the one for a non-oxidised sample. It is shown that the decrease of the concentration in the leachate mainly of As(V) is due to the formation of insoluble Ca3(AsO4)2 in the presence of Ca(OH)2. Extensive use was made of the speciation program MINTEQA2, to clarify the immobilisation of arsenic.     

脱硫废水引入渣溢水系统的处理效果分析

介绍了脱硫废水引入渣溢水系统的综合处理效果,对处理后水质指标及影响因素进行了长期跟踪分析,结果表明：处理后各水质指标均符合废水回用或排放标准,脱硫废水引入渣溢水系统处理是可行的。     

Recycling of low-silicate iron tailings in the production of lightweight building materials

Journal of Material Cycles and Waste Management - A feasible process for preparing lightweight building materials from the low-silicate iron tailings was developed. Various proportions of...     

Use of slag for dye removal

Adsorption techniques employing activated carbon have been found to be reasonably effective in the removal of some of the ionic impurities in water. However, economic considerations may require the use of inexpensive sorbents which are either naturally available or available as waste products from manufacturing processes. Slag is one such waste product obtained during the manufacture of steel, and the present study investigates dye removal characteristics of slag from colored waters. Aqueous solutions prepared from commercial grade acid, basic, and disperse dyes were used in this study, and batch pH, kinetic, and isotherm studies were undertaken on a laboratory scale. The data were evaluated for applicability to the Langmuir, Freundlich, and BET isotherm models, and the removal capacity of slag was compared with that of granular activated carbon. Results indicated approximately 94% removal of the disperse dye by slag, compared with a removal of approximately 49% achieved by activated carbon. Removal of acid dyes (dyes containing anionic groups) was reasonably good (approximately 47 and 74%), though not as good as obtained using activated carbon (approximately 100%). Column studies were conducted with a disperse dye (nonionic, slightly soluble in water), and analysis of data showed a sorption capacity of 1.3 mg of disperse dye per gram of slag. However, effluent dye concentrations were found to be higher than the permissible levels for discharge to receiving waters.     

Matt waste from glass separated collection: an eco-sustainable addition for new building materials

Matt waste (MW), a by-product of purification processes of cullet derived from separated glass waste collection, has been studied as filler for self-compacting concrete and as an addition for newly blended cement. Properties of self-compacting concrete compared to reference samples are reported. They include characteristics at the fresh and hardened states, and the compressive strength and porosity of mortar samples that were formulated with increasing amounts of MW to be used as cement replacement (up to 50wt.%). The effects of matt waste are discussed with respect to the mechanical and microstructural characteristics of the resulting new materials.     

Advances in the recycling of plastic wastes for metallurgical coke production

This paper aims to provide useful knowledge on the use of plastic wastes as additives to coking blends for the production of metallurgical coke. It focuses on the influence that the composition of plastic wastes has upon the development of coal fluidity, the generation of pressure during the coking process and the quality of the cokes produced in a semipilot oven. Several plastic mixtures of two types of thermoplastics, polyolefins (HDPE, LDPE and PP) and aromatic polymers such as PET, were used. The overall addition rate of plastics to a medium-fluid coal blend was 2 wt%. It is shown that polyolefins, weaker modifiers of coal fluidity, may be employed to maintain coke quality but that they have a negative effect on the generation of coking pressure, while plastics of the aromatic type such as PET, a strong modifier of coal fluidity, can be used to counteract the generation of coking pressure. From the results, it is deduced that the protocol developed is useful for determining the optimum amount of each type of polymer (polyolefins and aromatic polymers) that is needed in order to counteract the generation of pressure during the coking process and to maintain the quality of the cokes.     

Utilisation of IGCC slag and clay steriles in soft mud bricks (by pressing) for use in building bricks manufacturing

The subject of this study is the application to the construction of soft mud bricks (also known as pressed bricks), both green and heat-treated bodies, built from raw materials from Santa Cruz de Mudela, Ciudad Real, and IGCC slag from the power central of Puertollano (Ciudad Real, Spain). For this purpose, industrial level tests have been performed: the production of these kind of bricks from mixes of waste from ores of construction clays and to significant fraction of different ratios and clay granulometries mixed with IGCC slag. The results of this experimentation suggests that not only can IGCC slag be applied to a ceramic process, but also its use gives several advantages, as water and energy savings, as well as improvements on the final properties of products.     

Review on the innovative uses of steel slag for waste minimization

Piles of steel slag, a solid waste generated from the iron and steel industry, could be seen due to no utility found for the past century. Steel slag has now gained much attention because of its new applications. The properties of slag greatly influence its use and thus had got varied applications. The chemical composition of steel slag varies as the mineral composition of raw material such as iron ore and limestone varies. This paper reviews the characteristics of steel slag and its usage. The paper reviews recent developments in well-known applications to the steel slag such as aggregate in bituminous mixes, cement ingredient, concrete aggregate, antiskid aggregate, and rail road ballast. This paper also reviews novel uses such as mechanomutable asphalt binders, building material, green artificial reefs, thermal insulator, catalyst and ceramic Ingredient. The review is also done on utilization of solid waste for waste management by the novel methods like landfill daily cover material, sand capping, carbon sequestration, water treatment and solid waste management. Review also shows recovery of pure calcium carbonate and heavy metals from slag, providing opportunity for revenue generation. Steel slag once traded as free to use by steel industries is now sold in the market at some price. Its utilization is of great economic significance as it also contributes to the reduction of solid waste.     

Assessment of the use of spent copper slag for land reclamation.

The shortage of waste landfill space for waste disposal and the high demand for fill materials for land reclamation projects in Singapore have prompted a study on the feasibility of using spent copper slag as fill material in land reclamation. The physical and geotechnical properties of the spent copper slag were first assessed by laboratory tests, including hydraulic conductivity and shear strength tests. The physical and geotechnical properties were compared with those of conventional fill materials such as sands. The potential environmental impacts associated with the use of the spent copper slag for land reclamation were also evaluated by conducting laboratory tests including pH and Eh measurements, batch-leaching tests, acid neutralization capacity determination, and monitoring of long-term dissolution of the material. The spent copper slag was slightly alkaline, with pH 8.4 at a solid : water ratio of 1 : 1. The batch-leaching test results show that the concentrations of the regulated heavy metals leached from the material at pH 5.0 were significantly lower than the maximum concentrations for their toxicity limits referred by US EPA's Toxicity Characteristic Leaching Procedure (TCLP). It was also found that the material is unlikely to cause significant change in the redox condition of the subsurface environment over a long-term period. In terms of physical and geotechnical properties, the spent copper slag is a good fill material. In general, the spent copper slag is suitable to be used as a fill material for land reclamation.     

Flue gas desulfurization gypsum and coal fly ash as basic components of prefabricated building materials

The manufacture of prefabricated building materials containing binding products such as ettringite (6CaO·Al₂O₃·3SO₃·32H₂O) and calcium silicate hydrate (CSH) can give, in addition to other well-defined industrial activities, the opportunity of using wastes and by-products as raw materials, thus contributing to further saving of natural resources and protection of the environment.Two ternary mixtures, composed by 40% flue gas desulfurization (FGD) gypsum or natural gypsum (as a reference material), 35% calcium hydroxide and 25% coal fly ash, were submitted to laboratory hydrothermal treatments carried out within time and temperature ranges of 2 h–7 days and 55–85 °C, respectively. The formation of (i) ettringite, by hydration of calcium sulfate given by FGD or natural gypsum, alumina of fly ash and part of calcium hydroxide, and (ii) CSH, by hydration of silica contained in fly ash and residual lime, was observed within both the reacting systems. For the FGD gypsum-based mixture, the conversion toward ettringite and CSH was highest at 70 °C and increased with curing time. Some discrepancies in the hydration behavior between the mixtures were ascribed to differences in mineralogical composition between natural and FGD gypsum.     

Recycling of waste glass extracted from a WTP into ceramic materials

Journal of Material Cycles and Waste Management - Glass waste from an industrial wastewater treatment plant (WTP) was studied to recycle the material in ceramic materials. A white kaolinitic clay...     

Circular economy for durable products and materials: the recycling of plastic building products in Germany—status quo,potentials and recommendations

Journal of Material Cycles and Waste Management - The construction sector is the second largest area for the application for plastics. Due to the long life times of construction products, the...     

关于扶持再生资源回收产业发展的若干建议

受全球金融危机的影响及我国新税政的实施,我国再生资源回收产业陷入前所未有的困境.针对当前我国再生资源回收产业所面临的突出问题和实际困难,提出扶持再生资源回收产业发展的若干建议.