再生镁碳砖的性能、使用和质量控制

对再生镁碳砖和宝钢钢包渣线用新镁碳砖的性能指标、断面结构和使用效果进行了对比和分析,对提高再生镁碳砖质量和质量稳定性的措施进行了概括。结果表明:1)通过对拆炉、分拣、除杂、除渣、堆放和均化等每一环节的科学、细致、严格的管理,可以生产出优质的再生镁碳质原料;2)使用优质再生料,采用合理的生产工艺,可以生产出性能指标和使用效果达到甚至超过新镁碳砖的再生镁碳砖;3)再生镁碳砖使用效果好的原因是其致密度高,抗氧化性好,组织结构合理。     

Influence of ammonium salt on electrowinning of copper from ammoniacal alkaline solutions

In order to develop an energy-saving copper recycling process from wastes, electrochemical measurements were conducted in ammoniacal alkaline solutions containing Cu(I) ions and an ammonium salt of sulfate, chloride or nitrate. The results of each system were then compared. The polarization measurements suggested that the voltage required for the electrode process is lower in the chloride and nitrate systems than that in the sulfate system. The cathode current efficiency during the copper electrodeposition varied from 39 to 97% and increased with current density in the chloride and sulfate systems. In the nitrate system, the lowest cathode current efficiency of 30% was observed because of nitrate ion reduction. Based on these results, the power consumption required for the electrowinning stage of the copper recycling process was calculated. Among these three systems, the chloride system showed the lowest power consumption of 500 kWh t⁻¹ at the current density of 200 A m⁻², which is about 25% of the conventional copper electrowinning process from a copper sulfate-sulfuric acid solution.     

Neutralizing capacity of bottom ash from municipal solid waste incineration of different particle size

This study measures the neutralizing capacity of bottom ash from municipal solid waste incineration of different particle sizes. We examine the effect of particle size on the weathering process, a method popularly used for stabilization of heavy metals in incineration of bottom ash. The distribution of particle sizes in municipal solid waste incineration bottom ash is rather broad, ranging from fine powder to as large as 40 mm in diameter. Although considered a by-product highly suitable as a road construction material, the high level of heavy metal leaching is an obstacle to its reuse. Weathering, a method used to reduce heavy metal leaching, is a lengthy process taking over thee months to complete. The chief reaction involved in weathering is carbonation occurring between Ca(OH)2 in bottom ash and CO₂(g) in the atmosphere. During this process, CaCO₃ is produced, causing the pH level to drop from over 12 to about 8.2 and reducing heavy metal leaching. In this paper, we attempt to determine the particle size best suited for reducing the period required for weathering bottom ash by identifying characteristics of different particle sizes that affect heavy metal leaching and neutralization.     

钛白废酸回收装置国产化实践

南通三圣开发了拥有自主知识产权的“钛白废酸资源化回收利用的工艺技术及装置”,并通过了江苏省科技厅科技成果鉴定。从工艺技术革新、装置水平．经济效益及能耗分析、防腐材料及设备的开发、国产化装置的实施和优越性比较等几个方面证实了该装置的技术含量已世界先进水平．充分论证了钛白废酸的综合治理、回收利用是切实可行的。     

Application of Ozone in Textile Wastewater Treatment

Textile wastewaters are known to be highly resistant to biodegradation under both natural and wastewater treatment plant conditions. However, ozonation can be used to increase the biodegradability of the biologically resistant compounds. The combined method of ozonation and subsequent biodegradation of both synthetic and real textile wastes was explored in laboratory-scale studies. Two kinds of industrial wastes were simulated for effluents from dyehouse and washing machines. Upon determining the ozonation conditions of synthetic wastes, the real industrial wastes were investigated. The real textile wastewater was taken from textile factories, located in ód? , Poland, from subsequent stages of textile processing; dyeing, washing, rinsing and from an equalizer tank. Ozonation was carried out in a lab-scale bubble column sparged reactor, while the biological degradation proceeded in a trickle bed biofilter.     

絮凝沉降—臭氧氧化法处理硫化铜选矿废水试验

选矿厂废水排放量大,废水中固体悬浮物、浮选药剂、重金属离子等物质含量高,废水外排处理成本高且易造成二次污染,直接回用又影响浮选指标。因此,实现选矿废水的循环利用对节约有限的水资源,减少环境污染具有重要意义。模拟废水浮选试验结果表明:废水中的Al³⁺、Fe3³⁺对硫化铜矿浮选有显著抑制作用,Pb²⁺、Zn²⁺、Fe²⁺对硫化铜矿浮选影响较小;随着丁基黄药和Z-200浓度的增加,捕收剂对铜的选择性变差。采用絮凝—臭氧氧化工艺处理安徽某铜矿山选矿废水试验结果表明:聚丙烯酰胺对废水中的重金属离子及悬浮物具有显著的沉降效果;在整个pH期间,臭氧对丁基黄药去除效果显著,pH=8时,臭氧对Z-200去除效果最佳。采用絮凝沉降—臭氧氧化联合工艺处理后的选矿废水用于浮选试验,其浮选指标略低于清水浮选指标,远优于废水直接回用浮选指标。即应用此工艺处理硫化铜浮选总尾矿水,可有效降低水中不利组分的含量,实现水资源的高效利用。     

重庆大宝坡矿400 m水平以上非冶金用石灰岩 回收利用方案

针对大宝坡石灰石矿开采过程中非冶金石灰岩资源大量出露问题,对其回收利用方案进行了分析,确定了该矿400 m水平以上非冶金用石灰石的经济合理剥采比,解决了生产现场由于生产剥采比的最优化和均衡之间不协调的矛盾,开辟了矿山循环经济发展的新思路,可供类似矿山参考。     

地下矿搬迁新村规划区压覆资源回收方案研究

针对纳林庙二矿地表沉陷区居民安置问题考虑在矿权境界内设立居民搬迁新村规划区,通过可行性研究,提出了地下开采-充填法和爆破崩落和露天开采-回填复垦法2种压覆资源的回收方案。综合运用采矿作业与数理分析相结合、理论分析与实例相结合以及建立经济学模型等多种手段与方法对2种方案进行研究。通过对比这2种方案的经济效益和社会效益,决定采用爆破崩落-露天开采-回填复垦法进行资源回收。研究表明:采用该方案可成功回收规划区159.3 万t的压覆煤炭资源,创造直接经济效益15 090.4 万元。通过复垦将原来贫瘠的地貌改善为适宜人居,农林牧副渔协调发展的生态环境,实现了经济效益与社会效益的双赢。     

Understanding phosphorus phases in sewage sludge ashes: A wet-process investigation coupled with automated mineralogy analysis

Phosphorus (P) recovery from SSA (sewage sludge ashes) is highly relevant to address future P-shortages. Efficient recycling strategies require an in-depth knowledge of P-phases present. These may be subject to changes during treatment. Treatment was simulated, initial and treated material studied using automated mineralogy. Automated mineralogy, using the MLA system, is an established tool in ore processing evaluation and adapted here to examine P-phases in SSA. Coupling SSA treatment for P-recovery routines with MLA investigations allows for documenting phase compositions during chemical and thermochemical processes. Behaviour of P-phases during treatment and type of SSA govern P-recycling capacity. Findings lend additional insight to the identification of SSA types.Two different P-recovery routines have been investigated. Target phase groups (phosphates) have successfully been digested. Understanding phosphate setup in terms of composition, particle sizes and phase association is vital for an efficient P-extraction from SSA. P-recovery is not straightforward, but rather a series of steps in order to address different P-phase types. SSA is a complex secondary resource, which needs to be understood prior to P-extraction.     

Environmental impacts of the Swiss collection and recovery systems for Waste Electrical and Electronic Equipment (WEEE): a follow-up

While Waste Electrical and Electronic Equipment (WEEE) collection and recovery have significantly gained in importance all over Europe in the last 15 years, comprehensive studies assessing the environmental loads and benefits of these systems still are not common. In this paper we present the results of a combined material flow analysis and life cycle assessment study, which aimed to calculate the overall environmental impacts of collection, pre-processing and end-processing for the existing Swiss WEEE collection and recovery systems, as well as of incineration and landfilling scenarios, in which the same amount of WEEE is either incinerated in a an MSWI plant or landfilled. According to the calculations based on the material flow data for the year 2009 and a new version of the ecoinvent life cycle inventory database (ecoinvent v2.01), collection, recovery and disposal result in significantly lower environmental impacts per t of WEEE for midpoint indicators such as global warming or ozone depletion and the endpoint indicator Eco-Indicator '99 points. A comparison between the environmental impacts of the WEEE recovery scenarios 2009 and 2004, both calculated with ecoinvent v2.01 data, shows that the impacts per t of WEEE in 2009 were slightly lower. This appears to be mainly due to the changes in the treatment of plastics (more recycling, less incineration). Compared to the overall environmental impacts of the recovery scenario 2004 obtained with an old version of ecoinvent (ecoinvent v1.1), the calculation with ecoinvent v2.01 results in an increase of the impacts by about 20%, which is primarily the consequence of a more adequate modeling of several WEEE fractions (e.g. metals, cables or CRT devices). In view of a further increase of the environmental benefits associated with the Swiss WEEE collection and recovery systems, the recovery of geochemically scarce metals should be further investigated, in particular.