Hazardous Waste Minimization: Part VI Waste Minimization in the Foundry Industry

The foundry industry is a major consumer of waste materials (scrap). Unfortunately, the recycling of these waste materials can result in the generation of hazardous wastes that must be properly managed at a significant cost. This article focuses on two waste streams in the foundry industry; calcium carbide desulfurization slag and melt emission control residuals. The author presents an overview of how foundries have evaluated different waste management options with the ultimate goal of minimizing the generation of hazardous waste.     

Concepts of Electric Arc Furnace Fume Control

The capture of fumes from electric arc furnaces is described and the differences between foundry melting practices and steel industry practices are explained.     

Application of coupled thermostatted columns in civil engineering and for leaching heavy metals of wastes from foundry sands and mining industry

For many years, the mining industry at Pachuca Hidalgo, Mexico, has produced silver and gold through a cyanide process. Solid wastes (tailings) of this process have been deposited close to centres of population. Many of the metals in these wastes are dispersed via wind and rain, and can be toxic to flora and fauna. Foundry sands are wastes, produced by the automotive industry, the metallurgy industry and others, which are contaminated with many metals such as Fe, Cr, Zn, Pb, Au Ag, Ti, Ge, Co, As, Al, etc. We have previously patented a process for the extraction of toxic and valuable metals from foundry sands using a thermostatted column. The results of this study indicate that the process and the device could be used for removing heavy metals from tailings. In this research both types of waste (foundry sands and tailings) were leached using four coupled thermostatted columns. The presence of heavy metals in the solid wastes was studied using the ICP-AS technique and scanning electron microscopy, and to study the structure we used X-ray diffraction. After leaching we used the solid wastes (without toxic metals) to produce bricks. The mechanical properties of the bricks were assessed against international standards.     

Acoustic barriers obtained from industrial wastes

Acoustic pollution is an environmental problem that is becoming increasingly more important in our society. Likewise, the accumulation of generated waste and the need for waste management are also becoming more and more pressing. In this study we describe a new material--called PROUSO--obtained from industrial wastes. PROUSO has a variety of commercial and engineering, as well as building, applications. The main raw materials used for this environmentally friendly material come from slag from the aluminium recycling process, dust from the marble industry, foundry sands, and recycled expanded polystyrene from recycled packaging. Some natural materials, such as plastic clays, are also used. To obtain PROUSO we used a conventional ceramic process, forming new mineral phases and incorporating polluted elements into the structure. Its physical properties make PROUSO an excellent acoustic and thermal insulation material. It absorbs 95% of the sound in the frequency band of the 500 Hz. Its compressive strength makes it ideal for use in ceramic wall building.     

Waste green sands as reactive media for the removal of zinc from water

Waste green sands are industrial byproducts of the gray iron foundry industry. These green sands are composed of fine silica sand, clay binder, organic carbon, and residual iron particles. Because of their potential sorptive and reactive properties, tests were performed to determine the feasibility of using green sands as a low cost reactive medium in permeable reactive barriers (PRBs). Serial batch kinetic tests and conventional batch sorption tests were conducted to determine the removal characteristics for zinc in aqueous solutions. Removal characteristics for zinc in the presence of green sands are comparable to those of Peerless iron, a common reactive medium used in PRBs. High removal capacities for zinc of green sands are attributed to clay, organic carbon, and residual iron particles, which are known sorptive media for heavy metals. Furthermore, high pH values in the presence of clay and residual iron particles enhanced sorption and precipitation of zinc.     

Contaminants in waste foundry sand and its leachate

The environmental characteristics of Waste Foundry Sands (WFS), including chemicals in WFS and its leachate, are essential in understanding the environmental impact, rational disposal and potential development of beneficial applications of this solid industrial waste. This paper presents an assessment of broad-spectrum chemicals (metallic, non-metallic and organic chemicals) in aspects of their statistics (mean, median and the 95th percentile) in dry-weight WFS and WFS leachates based on laboratory measurements of 594 WFS samples from 123 foundry facilities in the USA. Results indicate that WFS is basically not hazardous except a risk associated with WFS from copper-based foundry facilities. Leachability of metallic chemicals varies among investigated WFS. A clear delineation between different leaching protocols is implicated.     

Product Guide/1980

Trace element concentrations of the lichen, Flavoparmelia caperata, were determined by neutron activation analysis before and after stringent participate controls were employed in an industrialized section of the Ohio River Valley; Initial studies in 1973 showed elevated concentrations of arsenic, cobalt, iron, vanadium, and titanium in lichens collected near coalfired power plants. Elevated values for cerium, chromium, and lanthanum were found in samples near a ferro-alloys foundry. A repeat study in 1987 demonstrated that lichen trace element concentrations were much lower after improved particulate controls were installed on the power plants and ferro-alloys foundry.     

Lead removal from foundry waste by solvent extraction

Solvent extraction is used to reduce lead concentrations from millpond wastewater solids, a type of foundry process waste. Toluene and toluene mixed with di-(2-ethyl-hexyl) phosphoric acid (HDEHP) have been tried as leaching solvents. Toluene is ineffective as a solvent in extracting lead, but the toluene-HDEHP mixture effectively removes lead from solid foundry waste. The effects of the HDEHP concentration, the contact time, and the amount of solvent used on lead extraction have been investigated. The mass transfer process is rapid: contact time of 1/2 hour has been found to be sufficient to accomplish the leaching process. The concentration of HDEHP significantly impacts lead removal. The optimum concentration of HDEHP is determined to range from 0.05 to 0.1 mol/l. The Toxicity Characteristic Leaching Procedure (TCLP) test of the treated samples gives leachable lead in much lower quantities than those found in the untreated samples. Thus the solvent extraction process appears to be an effective method to significantly reduce the lead content of millpond wastewater solids.     

Air Pollution Equipment for Foundry Cupolas

The choice of air pollution equipment best suited for a specific foundry cupola involves the consideration of a number of factors.—They are: (1) The design of the cupola, including openings, door enclosures, height of stack, etc. These features greatly affect the size, cost, and efficiency of control systems. (2) The constituents of the effluent gas and the other properties, such as temperature and volume, are extremely important because corrosion, warpage, and low efficiency can result from these variables. (3) Four distinctly different types of air pollution control equipment are available for cupolas. They vary widely in initial cost, operating cost, and maintenance, but also vary widely in efficiency. (4) Local air pollution regulations and community considerations dictate the choice of air pollution equipment. Those regulations now in force are quite stringent in some localities, but quite lenient in others. An incremental approach to installation of systems would make one economically feasible for the small foundry.     

Energy Consumption Requirements for Air Pollution Control Equipment at An Iron Foundry

Energy consumption requirements for air pollution control equipment were studied for varying removal efficiency levels at the Tyler Pipe Industries iron foundry in Tyler, Texas, based on plant fuel consumption data, and on field test measurements of cupola carbon monoxide and particulate control equipment. Natural gas consumption for CO removal increased from 0 in 1970 to 25.4% of the plant total in 1976. Operating costs to achieve 85% CO control increased from 0 in 1970 to $1.61/ton metal in 1976. Increasing cupola incinerator temperature from 800° to 1600° F increased CO removal efficiency from 60 to 97%, but also increased natural gas consumption by 150%. Electricity consumption requirements for 95% to 97% particulate control at the foundry increased from 0.1 % of plant total in 1970 to 18.7% in 1976. Electricity consumption for particulate controls increased plant operating costs from 0.004 in 1970 to 1.693 $/ton metal in 1976 as horsepower increased from 20 to 6,272. Cost-benefit methodology is needed to evaluate trade-offs between air pollution control, energy consumption requirements and operating costs of proposed regulations. Total air pollution control system must be considered in enforcing regulations instead of the source to be controlled alone for overall impacts. Need exists for process modifications to enhance energy recovery and development of energy-effective air pollution control equipment.     

Effectiveness of Odor Counteractants for the Treatment of Stack Gases

Successful control of some contaminant sources is extremely difficult to achieve technically and there remains a need for more information specific to control procedures. The cost of air cleaning equipment installations can be exceedingly high depending upon the performance standards to be satisfied and the physical and chemical characteristics of the contaminants. Control of emissions from the foundry cupola, the steel mill, metal refining operations, coal burning utilities, and incinerators still presents imposing cost and operational and performance problems—despite the technological progress made in recent years. The interrelationship of the source, the degree of control necessary, the equipment available to do the job, and the costs are discussed.     

废铸砂作为建筑材料资源化再利用研究进展

废铸砂是铸造工业在金属制品的生产过程中次生出来的一种细颗粒固体废弃物。研究其作为一种资源进行合理再利用是当前处置废铸砂、保护生态环境的良好对策。本文对废铸砂的环境特征、物理性质及废铸砂作为建筑材料在多种建筑制品及工程中的资源化再利用进行了综述研究,涉及的再利用领域包括混凝土、热拌沥青混合料、低强度填料、水泥、路基、路堤、阻水帷幕（屏障）和衬垫。调查发现,次生于黑色金属（铁和钢）铸造生产线的废铸砂是一种无害固体废弃物,正确处置和科学利用,对环境不会产生二次污染,在以上建筑制品及工程中的应用能满足相关技术、性能要求,可以替代相关的材料进行资源化再利用。     

Significance of urinary arsenic speciation in assessment of seafood ingestion as the main source of organic and inorganic arsenic in a population resident near a coastal area

In order to characterize the different sources of exposure to arsenic (As), urinary excretion of total As, the sum of inorganic As+MMA+DMA determined by the hydride generation-atomic absorption spectrophotometry technique, and the species As(3), As(5), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine were determined in 49 workers at a steel foundry, with presumed occupational exposure to As, and 50 subjects from the general population, all males. No evidence of occupational exposure to As resulted from environmental monitoring performed in the foundry, although the analysis of minerals used as raw materials showed the presence of As, particularly in fossils and fine ores. The urinary concentrations of As(3), MMA, DMA, the sum of inorganic As+MMA+DMA and total As were not different in the two groups, while arsenobetaine appeared significantly higher in the controls than in the workers. The different species of urinary As were all significantly correlated. Urinary excretion of As(3) was associated with the consumption of mineral water and with residence in an industrial zone, while MMA, DMA, arsenobetaine, the sum of inorganic As+MMA+DMA and total As urinary excretion were associated with the consumption of crustaceans and/or shellfish 3 days or less before urine collection. Multiple regression analysis confirmed these results. In conclusion, in populations with a high consumption of seafood, living in areas characterized by coastal/marine As pollution, only speciation of As can identify a prevalent role of environmental sources, like the consumption of seafood contaminated by As, in determining urinary As excretion, and exclude an occupational origin of the exposure.     

Hazardous waste sites and property values: a French case study in the light of US analyses

This paper aims to evaluate the impact of a polluted site on property values by using the hedonic price method. The case study concerns a lead foundry in a previously industrialised area in northern France. The results are fairly convincing. The impact is confirmed, but appears to be especially apparent at relatively close distances. More than one mile away, the impact is much weaker. Moreover, a chronological analysis, which includes interaction terms, allows one to demonstrate a significant variability in results, depending upon the years being examined. The results obtained are compared with those derived from US studies. It appears that more than one mile away, the calculated impact values are fairly similar, about 1–2% of the average value of a house. In contrast, bearing in mind the higher average property values in the USA, gradient prices in absolute values are, in general, higher in that country.     

Prosopis juliflora--a green solution to decontaminate heavy metal (Cu and Cd) contaminated soils

Soil and plant samples (root and shoot) of Prosopis juliflora were collected in the vicinity of metal based foundry units in Coimbatore and assessed for their heavy metal content (Cu and Cd) to ascertain the use of P. juliflora as a green solution to decontaminate soils contaminated with Cu and Cd. The results showed that Cu and Cd content was much higher in plant components compared to their extractable level in the soil. Furthermore, there exist a strong correlation between the distance of the sources of industrial units and accumulation of heavy metals in plants. Accumulation of Cd in roots is comparatively higher than that of shoots. However, in case of Cu no such clear trend is seen. Considering the accumulation efficiency and tolerance of P. juliflora to Cd and Cu, this plant can be explored further for the decontamination of metal polluted soils. On the other hand, in view of heavy metal accumulate the practice of providing foliage and pods as fodder for live stock should be avoided.     

Measuring Inorganic and Alkyl Lead Emissions from Stationary Sources

Described are the results from studies done to provide test methods for state and local air pollution control agencies to measure accurately the lead emissions from stationary source stacks as required in the National Ambient Air Quality Standard for Lead. Separate test methods were developed for measuring inorganic lead and alkyl lead compounds. Inorganic lead is collected in a standard particulate sampling train, digested with 50% (V/V) nitric acid and 3% hydrogen peroxide and analyzed by atomic absorption spectrometry. Alkyl lead compounds are collected in iodine monochloride and analyzed by atomic absorption spectrometry without prior solvent extraction. Standard solutions of inorganic lead in dilute nitric acid are used to calibrate the spectrophotometer in both methods. The inorganic lead test method was evaluated using baghouse dust samples from a primary copper and a primary lead smelter and stack samples from a lead recovery furnace, a primary battery manufacturing plant, a gray iron foundry and a secondary lead smelter. The alkyl lead method was evaluated using alkyl lead motor mix fluids and samples from an alkyl lead manufacturing plant vent stack.     

Estimation and characterization of PCDD/Fs and dioxin-like PCBs from Chinese iron foundries

The iron foundry industry is considered to be a potential source of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). This study investigated the emission factors and total emission amounts of PCDD/Fs and dioxin-like polychlorinated biphenyls (DL-PCBs) from iron foundries in China. The concentrations and the World Health Organization toxicity equivalents (WHO-TEQs) are presented and the congener profiles are discussed in this paper.In the present work, 26 fly ash samples were collected and tested to quantify the PCDD/Fs and DL-PCBs generated by 14 plants of different scales, and five stack gas samples were collected from two (named as EFG and LFG) of those plants. The emission levels of PCDD/Fs and DL-PCBs indicated that hot-air cupolas had lower emissions than cold-air cupolas. When iron ore lump and sinter were used as raw material, the emission factors were about 250 ng TEQ t⁻¹ of product. However, if the raw material was scrap, the emission factors varied owing to the different contents of organic materials in the raw materials. It was found that the mean WHO-TEQ values of PCDD/Fs and DL-PCBs were 144 and 34.2 pg Nm⁻³ in stack gas and 20.0 and 1.58 pg g⁻¹ in fly ash. In multiple tests, it was estimated that the mean emission factors of PCDD/Fs and DL-PCBs were 365 and 10.9 ng WHO-TEQ t⁻¹ released to residue and 2719 and 555 ng TEQ t⁻¹ released to air. The total emission amounts of PCDD/Fs and DL-PCBs from Chinese iron foundries with cupola furnaces released to residue and air were 16.8 and 146 g WHO-TEQ in 2008, respectively.     

化工园区废气管理问题及对策

近年来,化工园区面临绿色转型升级,废气管理提升重要程度日益突显。本文分析了化工园区废气管理存在的主要问题,并提出了化工园区废气管理对策,以期提升化工园区废气综合管理水平,改善化工园区空气环境质量。     

Hazardous Waste Minimization: Part V Waste Minimization in the Petroleum Industry

The extractive nature of the petroleum industry sets it apart from other industries in many respects. The nature of this industry places it at somewhat of a disadvantage to other industries when attempts are made to foster waste minimization practices and programs. However, this is no excuse for the industry to not further vigorously pursue minimizing waste. This paper describes the petroleum industry and the products it makes along with their associated waste streams. The industry’s commitment to waste minimization is described with examples of specific minimization projects provided. Although the opportunities for minimization are limited, the economic incentives for reducing waste disposal costs, not to mention long term liability from improper disposal practices, has put the petroleum industry on the road to waste minimization.     

The role of multiple regression and exploratory data analysis in the development of leukemia incidence risk models for comparison of radionuclide air stack emissions from nuclear and coal power industries

Risks associated with power generation must be identified to make intelligent choices between alternate power technologies. Radionuclide air stack emissions for a single coal plant and a single nuclear plant are used to compute the single plant leukemia incidence risk and total industry leukemia incidence risk. Leukemia incidence is the response variable as a function of radionuclide bone dose for the six proposed dose response curves considered. During normal operation a coal plant has higher radionuclide emissions than a nuclear plant and the coal industry has a higher leukaemia incidence risk than the nuclear industry, unless a nuclear accident occurs. Variation of nuclear accident size allows quantification of the impact of accidents on the total industry leukemia incidence risk comparison. The leukemia incidence risk is quantified as the number of accidents of a given size for the nuclear industry leukemia incidence risk to equal the coal industry leukemia incidence risk. The general linear model is used to develop equations that relate the accident frequency required for equal industry risks to the magnitude of the nuclear emission. Exploratory data analysis revealed that the relationship between the natural log of accident number versus the natural log of accident size is linear.