钙法提钒尾渣的浮选脱硫试验

根据钙法提钒尾渣的矿物特性,采用浮选法分离其中的石膏以实现脱硫,分别考察了矿浆pH、矿浆液固比、捕收剂添加量及浮选中水循环次数等因素对浮选指标的影响,并进行了理论分析,确定了钙法提钒尾渣浮选脱硫的优选工艺参数.试验结果表明,在矿浆pH为7、矿浆液固比为5:1、捕收剂添加量为0.6～0.8 kg/t的条件下,可获得w(S...     

Phase transformation mechanism of boiler ash roasted with sodium salt for vanadium extraction

Journal of Material Cycles and Waste Management - Boiler ash, produced by burning heavy fuel oil (HFO) in electrical power plants, is one of the most serious environmental problems facing oil-rich...     

Processing of copper anodic-slimes for extraction of valuable metals

This work focuses on processing of anodic slimes obtained from an Egyptian copper electrorefining plant. The anodic slimes are characterized by high concentrations of copper, lead, tin and silver. The proposed hydrometallurgical process consists of two leaching stages for the extraction of copper (H(2)SO(4)-O(2)) and silver (thiourea-Fe3+), and pyrometallurgical treatment of the remaining slimes for production of Pb-Sn soldering alloy. Factors affecting both the leaching and smelting stages were studied.     

Ecological treatment of El Kriymat boiler ash for recovering vanadium,nickel and zinc from sulfate leach liquor

The primary goal of this work is to develop a technology that allows for the recovery of metal values from waste products, thereby promoting the wise and efficient use of our nation's resources. To achieve this goal, an industrial waste of El Kriymat boiler fly Ash was used for recovering its content of vanadium, nickel and zinc. About 97, 95 and 99% respectively of these economic elements were first dissolved from boiler fly ash magnetic concentrate (after physical concentration). Leaching experiments using optimum conditions include: 180 g/L sulfuric acid concentration and 4% solid/solid proportion manganese dioxide acts as an oxidant at 80 °C. The recovery of vanadium (V) metal ions was carried out using 3% Alamine 336 in kerosene at an equilibrium pH value of 0.9. Subsequently, 15% sodium sulfide solution was used for co-precipitation of nickel and zinc metal ions in the raffinate solution at pH value of 3.5.

Graphical Abstract

     

我国石煤提钒废水的处理现状与展望

石煤提钒废水中含有大量的重金属、氨氮和盐类。介绍了石煤提钒中重金属废水、氨氮废水、高盐废水的处理技术,总结了各种废水处理技术在石煤提钒废水治理中的应用现状,并对石煤提钒废水的治理进行了展望。化学法应用广泛,但易造成二次污染;物理法具有广阔的应用前景,但处理效率低;生物法具有效率高、选择性强、废水处理成本低等优点,是一种极具发展潜力的废水治理方法,应加大在石煤提钒废水治理方面的研究。     

Simultaneous recovery of vanadium and nickel from power plant fly-ash: Optimization of parameters using response surface methodology

Simultaneous recovery of vanadium (V) and nickel (Ni), which are classified as two of the most hazardous metal species from power plant heavy fuel fly-ash, was studied using a hydrometallurgical process consisting of acid leaching using sulfuric acid. Leaching parameters were investigated and optimized in order to maximize the recovery of both vanadium and nickel. The independent leaching parameters investigated were liquid to solid ratio (S/L) (5–12.5 wt.%), temperature (45–80 °C), sulfuric acid concentration (5–25 v/v%) and leaching time (1–5 h). Response surface methodology (RSM) was used to optimize the process parameters. The most effective parameter on the recovery of both elements was found to be temperature and the least effective was time for V and acid concentration for Ni. Based on the results, optimum condition for metals recovery (actual recovery of ca.94% for V and 81% for Ni) was determined to be solid to liquid ratio of 9.15 wt.%, temperature of 80 °C, sulfuric acid concentration of 19.47 v/v% and leaching time of 2 h. The maximum V and Ni predicted recovery of 91.34% and 80.26% was achieved.     

Cost effectiveness of abatement options for emissions control in Egyptian iron foundries

This study focuses on an evaluation of the cost effectiveness of abatement options for controlling emissions in existing iron foundries in Egypt. It is expected that such a study will enable decision by identifying concrete measures for abating total solid emissions (TSP). The structure of iron foundries in the country have been surveyed and the variant types of furnaces, the TSP emission level without any abatement options and data of the annual turnover of these foundries have been obtained. Possible market based instruments (MBI) options that might encourage these firms to seek the most efficient control measures have also been examined. Different abatement options such as updating burner design, switching heavy fuel oil to kerosene or natural gas, installing cleaning systems and/or updating the process technology were tested in terms of emission level and the overall turnover. The effect of installing different cleaning systems such as wet scrubbers and filter bags on the running cost of abating TSP was also investigated. Results obtained reveal that crucible (CrF) and short rotary (SRF) furnaces are the most numerous types of plants in Egypt. The concentration of TSP emissions exceeds the standards as specified in Law. Poor quality scrap input adversely affects the operation of the furnace, and impairs product quality and causes excessive TSP emissions. TSP emissions per ton of cast iron produced are relatively low for induction furnaces (EIFs), (about 0.04 kg) and very high in the dirtier technologies, particularly CrF and SRF, (29.95 and 32.2 kg, respectively). Cost analysis shows that the cost of abating one ton of TSP emitted amounts to 3000–5000 L.E and this cost represents a high percentage of turnover to plants abating emissions. A program for technical assistance and training would help iron foundries solving difficulties in reducing TSP emissions and encourage them to implement and operate effective pollution control measures. The work suggests structural changes such as: updating equipment; design of furnaces and cleaning of dirty scrap before use. Unification of small foundries in larger plants may provide funding to successfully abate TSP emissions. Financial support or assistance for pollution abatement by firms have had no impact so far. This is because such help has little effect on operating costs. In this context, a proposal for relocating iron foundries in new industrial areas seems to be immaterial if plants move without implementing acceptable abating options.     

废弃SCR催化剂中钒和钨的浸出及回收

采用NaOH溶液一次性浸出废弃SCR催化剂中的钒和钨,并用硫酸对浸出液进行除杂,再利用NH4Cl和硫酸分步对浸出液中的钒和钨进行沉淀回收。在NaOH质量分数40%、液固比8、浸出时间4 h、浸出温度90℃的最佳碱浸条件下,钒和钨的浸出率分别达到90.44%和84.49%。除杂过程的铝去除率达到100%,硅去除率达到77.56%。在沉钒pH为8.0、n(NH_4~+)∶n(V)为4的最佳沉钒条件下,钒回收率达到82.79%。在n(SO_4~(2-))∶n(W)为2的最佳沉钨条件下,钨回收率达到76.41%。     

Evaluation of leaching and extraction procedures for soil and waste

Laboratory leaching tests may be used for source term determination as a basis for risk assessment for soil-groundwater pathways on contaminated sites. In order to evaluate different leaching procedures, batch extraction tests and percolation tests were performed using three reference materials produced from contaminated soil, demolition waste and municipal solid waste incinerator bottom ash. Emphasis was placed on the investigation of the leachability of the heavy metals copper and chromium, polycyclic aromatic hydrocarbons (PAHs) and the anions chloride and sulfate. Significant discrepancies between column experiments and batch/extraction tests were found for the release of PAHs and to a lesser extent for the heavy metals Cu and Cr. Additionally interlaboratory comparisons were conducted based on different leaching tests with the reference materials and evaluated using the criteria of comparability and reproducibility. The best reproducibility was achieved for all investigated substances in column tests. The reproducibility of batch tests was acceptable except for PAHs. The results from the experimental work will help establish standardized and feasible laboratory procedures as fundamental for substance specific risk assessment of contaminated sites.     

Graphene Oxide Caged Biopolymer Nanocomposite for Purification of Rare Earth Elements from High Grade Egyptian Monazite Concentrate

Journal of Polymers and the Environment - Rare earth elements (REEs) play a critical role in the applications of advanced materials. In this respect, an eco-friendly calcium/alginate-graphene oxide...     

Application of mechanical processing operations for the recycling of nickel metal hydride batteries

Journal of Material Cycles and Waste Management - Rapid technological development in recent decades has led to very high generation of waste electrical and electronic equipment, including exhausted...     

钴镍金属二次资源回收利用现状及发展对策研究

介绍了世界钴镍金属资源分布及其二次资源综合利用概况.以国内外废旧电池和催化剂中的钴镍资源为例,对其回收体系和利用技术现状进行了概述,并提出了存在的问题和解决问题的建议.     

废SCR催化剂中钒和钨的有机酸浸出

在对废SCR催化剂组成进行分析的基础上,采用草酸和酒石酸两种有机酸浸取废SCR催化剂中的V和W。实验结果表明：草酸对V、W的浸出率均大于酒石酸;在草酸浓度为1.00 mol/L、浸取温度为80 ℃、液固比为10 mL/g、浸取时间为180 min时,V和W的浸出率分别为63.50%和13.12%;在酒石酸浓度为0.5 mol/L、浸取温度为100 ℃、液固比为10 mL/g、浸取时间为180 min时,V和W的浸出率分别为44.00%和9.00%。酸性浸出未改变SCR催化剂中TiO₂的晶型,剩余残渣中依然保留着TiO₂骨架,可继续作为催化剂载体使用。     

关于建立废弃电器电子产品处理基金的目的和政策思路

2010年12月7日,中国再生资源回收利用协会电子废弃物回收处理分会召开了"废弃电器电子产品基金补贴及回收管理办法征求意见研讨会",国家财政部、环保部、商务部等有关司局参与文件起草的负责同志在会上详细介绍了与国务院颁布的《废弃电器电子产品回收处理管理条例》相配套的管理办法等文件的指导思想、目的与具体内容,现将他们的讲话刊登如下,供广大读者参考。     

Electro-dissolution of metal scrap anodes for nickel ion removal from metal finishing effluent

This contribution reports a novel and cost efficient strategy for nickel ion removal from metal finishing effluents by electro-dissolution of scrap aluminium and iron sacrificial anodes. Electro-coagulation of effluent was carried out at 30 mA/cm² current density for 60 min. The nickel ion concentration of electroplating effluent was analysed by Atomic Absorption Spectroscopy. SEM images of iron and aluminium scrap anodes were critically analysed. Parameters such as heavy metal removal, anode dissolution rate with respect to heavy metal removal, reaction kinetics and cost estimation have been elaborately studied. Electro-coagulation at 30 mA/cm² for 60 min using iron and aluminium scrap anodes resulted in 95.9 and 94.1 % nickel ion reduction, respectively, with 0.0094 and 0.0053 g/ppm dissolution rates. The energy consumption for scrap aluminium and iron anodes was 0.0547 kWh/L. Loose internal bonding and spongy surface morphology of used metal scrap render high porosity and active surface area, enhancing reaction rate. Low cost and ready availability of waste scrap makes the process of electro-coagulation economically viable. Thus, the findings from this contribution point decisively at the superiority of waste metal scrap-based anodes for economic and environmentally sustainable heavy metal ion removal from metal finishing effluent.     

Recovery of nickel oxide from spent catalyst

This study investigates the possibility of recovering nickel from the spent catalyst (NiO/Al2O3) resulting from the steam reforming process to produce water gas (H2/H2O) in many industries. In the extraction process, nickel is recovered as sulfate using sulfuric acid as a solvent. The considered parameters affecting nickel recovery were acid concentration, temperature and time of digestion solid:liquid ratio, particle size and stirring rate. Nickel was to be directly recovered as a sulfate salt by direct crystallization method. The conversion was 99% at 50% sulfuric acid concentration, solid: liquid ratio (1:12) by weight, particle size less than 500 micron for more than 5 h and 800 rpm at 100 degrees C.     

Pozzolanic activity enhancement of magnesium-rich nickel slag and geopolymer preparation

Journal of Material Cycles and Waste Management - The pozzolanic activity of magnesium-rich nickel slag (HMNS) was improved by remelting and quenching method, the changes of mineralogical phase,...     

Bio-processing of solid wastes and secondary resources for metal extraction - A review

Metal containing wastes/byproducts of various industries, used consumer goods, and municipal waste are potential pollutants, if not treated properly. They may also be important secondary resources if processed in eco-friendly manner for secured supply of contained metals/materials. Bio-extraction of metals from such resources with microbes such as bacteria, fungi and archaea is being increasingly explored to meet the twin objectives of resource recycling and pollution mitigation. This review focuses on the bio-processing of solid wastes/byproducts of metallurgical and manufacturing industries, chemical/petrochemical plants, electroplating and tanning units, besides sewage sludge and fly ash of municipal incinerators, electronic wastes (e-wastes/PCBs), used batteries, etc. An assessment has been made to quantify the wastes generated and its compositions, microbes used, metal leaching efficiency etc. Processing of certain effluents and wastewaters comprising of metals is also included in brief. Future directions of research are highlighted.