冶金污泥稳定化/固化处理工艺研究

冶金工业在生产过程中产生大量酸性废水.对这类废水目前通常采用石灰中和沉淀处理.文章中通过研究采用水泥和工业废渣作固化基材固化处理冶金工业酸性废水用石灰混凝所产生的含铜、砷的污泥,分析了影响固化块抗压强度的多种因素,采用固体废物浸出毒性浸出方法对浸出率进行实验探讨.     

蒸发-固化法处理垃圾渗滤液反渗透浓缩液的研究

采用蒸发-固化工艺处理垃圾渗滤液反渗透浓缩液。蒸发工艺可将反渗透浓缩液减量化,固化工艺可将蒸发残留液中的污染物稳定化。研究表明,蒸发残留液宜采用水泥和石灰混合料进行固化,混合料最佳水泥与石灰质量比约为1︰2,每100 mL蒸发残留液(质量约为120 g)最佳投加量为50 g。固化体含水率低于40%,抗压强度高于1.0 MPa,适合填埋处置,其浸出液污染物含量较低。采用硅酸钠和硫酸钙作为添加剂可加快固化速度,提高固化体的抗压强度。利用蒸发-固化工艺处理反渗透浓缩液可取得良好的经济和社会效益。     

Optimising energy recovery and use of chemicals,resources and materials in modern waste-to-energy plants

Due to ongoing developments in the EU waste policy, Waste-to-Energy (WtE) plants are to be optimized beyond current acceptance levels. In this paper, a non-exhaustive overview of advanced technical improvements is presented and illustrated with facts and figures from state-of-the-art combustion plants for municipal solid waste (MSW). Some of the data included originate from regular WtE plant operation – before and after optimisation – as well as from defined plant-scale research. Aspects of energy efficiency and (re-)use of chemicals, resources and materials are discussed and support, in light of best available techniques (BAT), the idea that WtE plant performance still can be improved significantly, without direct need for expensive techniques, tools or re-design. In first instance, diagnostic skills and a thorough understanding of processes and operations allow for reclaiming the silent optimisation potential.     

铬渣的固化/稳定化研究

探讨了用水泥粘结剂对铬渣进行稳定化的方法。结果表明，把高炉矿渣和粉煤灰加入水泥基材中对铬渣进行固化，固化体抗压强度达到30MPa以上，浸出毒性大大降低，浸了同液中六价铬浓度在容许范围内，建议可以综合利用。     

纤维改性硫酸亚铁还原铬渣水泥固化体研究

以浸出毒性、表面浸出率、抗日晒能力和抗压强度为指标考察了纤维改性硫酸亚铁还原铬渣水泥固化体的性能。实验结果表明：纤维改性硫酸亚铁还原铬渣水泥固化体养护7d和28d后的浸出毒性均低于国家标准、抗压强度均大于10MPa,可以做最终处置或进行综合利用;与普通铬渣水泥固化体相比,纤维改性硫酸亚铁还原铬渣水泥固化体在加入植物纤维为0．8g时的处理效果最好,浸出毒性、表面浸出率分别降低了76．I％和76．8％;抗日晒能力、抗压强度分别提高了36．4％和52．1％。     

医疗焚烧废渣的固定化试验研究

医疗垃圾属于国家规定的危险废物,焚烧后的残渣同样存在最后稳定化的问题,国外处理方法主要是填埋和基础回填,本文通过对两种胶凝材料(普硅水泥和复合矿渣水泥)对医疗废渣的固定化效果研究,探讨医疗废渣再利用的可行性和影响因素。     

An integrated method for the rapid dewatering and solidification/stabilization of dredged contaminated sediment with a high water content

• An integrated method, called PHDVPSS, was proposed for treating DCS. • The PHDVPSS method showed superior performance compared to conventional method. • Using the method, water content (%) of DCS decreased from 300 to<150 in 3 days. • The 56-day UCS from this method is 12‒17 times higher than conventional method. • Relative to PC, GGBS-MgO binder yielded greater reduction in the leachability. To more efficiently treat the dredged contaminated sediment (DCS) with a high water content, this study proposes an integrated method (called PHDVPSS) that uses the solidifying/stabilizing (S/S) agents and prefabricated horizontal drain (PHD) assisted by vacuum pressure (VP). Using this method, dewatering and solidification/stabilization can be carried out simultaneously such that the treatment time can be significantly shortened and the treatment efficacy can be significantly improved. A series of model tests was conducted to investigate the effectiveness of the proposed method. Experimental results indicated that the proposed PHDVPSS method showed superior performance compared to the conventional S/S method that uses Portland cement (PC) directly without prior dewatering. The 56-day unconfined compressive strength of DCS treated by the proposed method with GGBS-MgO as the binder is 12‒17 times higher than that by the conventional S/S method. DCS treated by the PHDVPSS method exhibited continuous decrease in leaching concentration of Zn with increasing curing age. The reduction of Zn leachability is more obvious when using GGBS-MgO as the binder than when using PC, because GGBS-MgO increased the residual fraction and decreased the acid soluble fraction of Zn. The microstructure analysis reveals the formation of hydrotalcite in GGBS-MgO binder, which resulted in higher mechanical strength and higher Zn stabilization efficiency.     

Environmental behaviour of a construction made of a mixture of hydraulic binders and air pollution control residues from municipal solid waste incineration Part 1. Physico-chemical characterisation and modelling of the source term

The reuse of waste materials requires the development of assessment methods for the long-term release of pollutants (source term) from wastes (or materials containing wastes) in contact with water. These methods depend on the scenario conditions: characteristics of the materials (especially physical structure and composition), contact with water. The scenario studied here is a water storage reservoir for fire fighting. The reservoir construction is made of a mixture of hydraulic binders and air pollution control (APC) residues from a municipal solid waste incinerator (MSWI). The modelling of the source term is performed in 5 steps ranging from the physico-chemical characterisation of the material to the validation of the proposed model by means of field simulation devices. This article presents the first steps of the methodology: physico-chemical characterisation of the source term, identification of the main transfer mechanisms and laboratory scale modelling of the source term. During the physico-chemical characterisation, it has been shown that the solidified waste shows a high basic capacity and that a relative decrease in pH during leaching favours retention of the main pollutants. During the first leaching sequences, the dynamic leaching tests show that the release of pollutants such as cadmium, arsenic, zinc and lead is extremely low but that the release of alkaline species (sodium and potassium) and chloride is very high from the beginning, whereas the release of calcium remains very high even after 3600 h of leaching. Identification of the main transfer mechanisms concludes that the release of soluble pollutants is the combined result of diffusional transfer of pollutants in the solution and the physico-chemical specificity of the species. The modelling based on these features enables a good simulation of the release but reveals a deviation from the experimental results after 500 h for alkaline species and 1000 h for Ca and Cl leaching. However, this deviation only appears after release of the major part of these elements.     

水泥对垃圾焚烧飞灰的固化处理试验研究

对垃圾焚烧飞灰的化学成分、重金属物质的含量及浸出浓度进行测试分析.结果表明,飞灰中Pb和Cr等重金属物质浸出量超过浸出毒性标准,因而被认为是危险废物,必须进行固化处理.还考察了水泥对焚烧飞灰中重金属物质固化的效果,研究表明当飞灰掺量适当时,重金属物质的固化效果良好.重金属物质通过物理固封、替代,沉淀反应和吸附等形式可固化进水泥水化产物结构中.     

双辊快速凝固技术的研究进展

综述了双辊快速凝固技术在凝固特征及组织方面的研究进展,讨论了相关工艺参数对产品质量的影响,并介绍了该技术的应用现状和发展前景.