冶金工业固体废物钢渣的综合利用

首先概述了钢渣的来源、化学组成及加工方法等;其次对钢渣的国内外综合利用途径进行了综述,分别介绍了利用磁选工艺回收废钢铁,作为冶金原料、建筑材料,以及在农业和水处理方面的应用特点和应用实例,并指出,在农业和水处理方面,钢渣具有广泛的应用价值和显著的社会经济效益;最后对钢渣综合利用的前景进行了展望,提出了加快钢渣资源化利用的建议。     

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。     

Development of rice husks-plastics composites for building materials

In this paper, a new effective recycling method for rice husks and waste expanded polystyrene is developed by using a combination of both wastes. A styrene solution of waste expanded polystyrene is used as a binder for rice husks-plastics composites. The composites are prepared with various mix proportions by a hot press molding method, and tested for apparent density, water absorption, expansion in thickness, and dry and wet flexural strengths. From the test results, the apparent density of the composites is increased with increasing binder content and filler-binder ratio. Their flexural strength and wet flexural strengths reach maximums at a binder content of 30.0% and a filler-binder ratio of 1.0. Their water absorption and expansion in thickness are decreased with increasing binder content and filler-binder ratio. Since the composites have a high flexural strength and water resistance, their uses as building materials are expected.     

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。     

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.     

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.     

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。     

Effects of EDTA on the accelerated carbonation behavior of steel slag used as cementitious materials

Journal of Material Cycles and Waste Management - To utilize the steel slag (SS) on a large scale and sequester CO2, a room-temperature wet carbonation process with the assistance of...     

Recycling municipal incinerator fly- and scrubber-ash into fused slag for the substantial replacement of cement in cement-mortars

Fly- and scrubber-ash (weight ratio of approximately 1:3) from municipal solid waste incinerators (MSWI) are a major land-fill disposal problem due to their leaching of heavy metals. We uniformly mixed both types of ash with optimal amounts of waste glass frit, which was then melted into a glassy slag. The glassy slag was then pulverized to a particle size smaller than 38 μm for use as a cement substitute (20–40% of total cement) and blended with sand and cement to produce slag-blended cement-mortar (SCM) specimens. The toxicity characteristics of the leaching procedure tests on the pulverized slag samples revealed that the amount of leached heavy metals was far below regulatory thresholds. The compressive strength of the 28-day cured SCM specimens was comparable to that of ordinary Portland cement mortars, while the compressive strength of specimens cured for 60 or 90 days were 3–11% greater. The observed enhanced strength is achieved by Pozzolanic reaction. Preliminary evaluation shows that the combination of MSWI fly- and scrubber-ash with waste glass yields a cost effective and environmentally friendly cement replacement in cement-mortars.     

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...     

锰渣脱硫制硫酸锰技术在电解锰行业的应用

介绍了某电解锰企业锰渣煅烧含高浓度SO₂烟气的资源化处理路线,阐述了氧化锰矿浆烟气脱硫制MnSO₄技术的工艺设计。该烟气脱硫制MnSO₄装置运行稳定,尾气中SO₂质量浓度为32.1~51.9 mg/m³,达到排放设计要求,脱硫装置产生的MnSO₄浆液中Mn²⁺质量浓度为(40±1)g/L,连二硫酸锰质量浓度小于5 g/L,满足电解锰生产要求。     

Reuse of textile effluent treatment plant sludge in building materials

This study examines the potential reuse of textile effluent treatment plant (ETP) sludge in building materials. The physico-chemical and engineering properties of a composite textile sludge sample from the southern part of India have been studied. The tests were conducted as per Bureau of Indian Standards (BIS) specification codes to evaluate the suitability of the sludge for structural and non-structural application by partial replacement of up to 30% of cement. The cement-sludge samples failed to meet the required strength for structural applications. The strength and other properties met the Bureau of Indian Standards for non-structural materials such as flooring tiles, solid and pavement blocks, and bricks. Results generally meet most ASTM standards for non-structural materials, except that the sludge-amended bricks do not meet the Grade NW brick standard. It is concluded that the substitution of textile ETP sludge for cement, up to a maximum of 30%, may be possible in the manufacturing of non-structural building materials. Detailed leachability and economic feasibility studies need to be carried out as the next step of research.     

The building materials decree: an example of a Dutch regulation based on the potential impact of materials on the environment

Some 20 years ago Dutch society became very aware of the problem of the increasing production of waste materials and of the need to find solutions. Technical solutions had to be developed and introduced into society. Due to the discovery of many soil pollution problems and other environmental calamities, people asked for clear criteria on which proper and safe solutions could be based. Therefore a large number of environmental aspects had to be taken into account in the developing field of environmental policy. The Dutch building materials decree is one of the steps on the road towards a sustainable society. The decree is based on the soil protection act and the surface water protection act. The decree gives quality criteria for the application and re-use of stony materials and earth used as building materials. No difference is made between primary materials, secondary materials and waste materials. The decree is applicable in case these materials are used in constructions where they are in contact with rain, surface water and ground water (e.g. in embankments, road building, outside walls of buildings, foundations and roofs). For implementation of the decree in the construction industry it was necessary to develop standards, methods for testing and certification schemes. In order to guarantee independent testing and judgement, laboratories had to meet quality standards put forward in an accreditation scheme. Although this legislation does not cover all environmental aspects, it has proved to be an important element in judging the environmental quality of construction materials in a direct or indirect way, and a contribution to the management of waste materials. The question of clear and fair criteria was easily put forward. Answering this question, however, turned out to be a complex task in which a great number of aspects had to be considered and a great many tools had to be developed, checked and thoroughly discussed. In some cases practical choices had to be made in order to prevent an unclear situation continuing too long. After an introduction period of three years, the decree came into full operation on 1 July 1999.     

A novel method for preparing phosphorus building gypsum (PBG)-based building materials with low water/gypsum ratios

Journal of Material Cycles and Waste Management - It is necessary to consider the dual problems of poor performance and low production efficiency that stem from the highly utilised water/gypsum...     

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.