This packet contains summaries of the DOE/OIT or other roadmaps for the steel, aluminum, casting, polymers, automotive, electronics, and mining industries. While there are some similarities in the types of relevant environmental issues and the classes of solutions used, the industries under study have some differences in approach to environmental issues.
The primary metals producers have energy intensive processes. Primary aluminum production is particularly energy intensive. Many of the metal reduction and metal-making processes have been used for a century or more. Coal is commonly used as an energy source in steel production and some airborne environmental emissions, such as dust, NOx, and SOx, can be attributed directly to coal. Generally for both steel and aluminum, there is a large quantity of heavy metal-contaminated slag (solid material) that must be disposed of or used in a material-intensive application, such as construction. There is also waterborne sludge, in particularly large quantities for aluminum. Both the aluminum and steel industries have prioritized development of efficiency improvements in existing production processes, substitute production processes, and improved recycling technologies.
The necessity of downstream processes (such as machining and welding) is being reduced through developments in near net shape casting. Casting has its own problems: most notably the generation of large quantities of spent foundry sand. As the casting industry is populated by large numbers of small operations, it is more challenging for the industry to develop a unified environmental strategy.
Increasingly precise specifications of engineering materials coupled with reduced in-house scrap production rates are posing system-level problems for metal recycling. A wider array of alloy formulations makes post-consumer scrap separation more difficult. Increasing demands for more consistent material properties leads to a decreasing tolerance for impurities. These two trends combine to result in higher energy requirements and/or more waste production in recycling processes.
The major environmental concerns in polymer manufacture are energy use and release of toxic emissions. Polymers have more dramatic separation and impurity problems for recycling, as there are generally even more types of polymers that are more difficult to separate. Even characteristics such as color can pose separation challenges. For these reasons, polymers are commonly recycled into lower grade materials.
Prioritizing environmental improvement effort is a challenge for both the electronics and the automotive industries. The electronics industry is characterized by relatively rapid changes in technology performance, which is directly tied to rapid manufacturing process evolution, and thus the focus is on incorporating environmental considerations into new technology and manufacturing process development. In the electronics industry roadmap, much emphasis is placed on DfE tool development. Manufacturing technology in the automotive industry also changes, but at a less rapid rate: thus, there is more focus on isolation of the current processes for which environmental improvements would be the most beneficial. As the partitioning of environmental effects is more static, this prioritization can be done through an assessment method such as Life Cycle Analysis.
INDUSTRY - ALUMINUM
Aluminum is characterized by high energy intensity in primary production relative to recycled aluminum production (and also to that of other metals). However, there are also problems associated with recycling. Sorting and separating the alloys and impurities that are input into the recycling process can limit the applicability of recycling and also lead to increased solid waste and other emissions. Thus, much of the advocated research focus in the aluminum industry is on increased primary (Bayer and reduction) process energy efficiency, better separation methods, and use of process byproducts. For casting and semi-fabrication processes, the focus is on developing process innovations that increase energy efficiency while producing product of more consistent microstructure and material properties. For these processes, there is a particular emphasis on developing better process models and better in-process monitoring and real time control. For all processes, advocated research effort is three-tiered: first increasing efficiencies in current processes, second developing new processes to replace current processes, and third through a systems approach, reducing overall number of process steps required to produce a component.
Figure 1. Aluminum Manufacturing Process Chain.
The aluminum industry is very conscious of its competitive position against steel. Generally, steel has the cost advantage. The high energy cost for primary aluminum production gives motivation for increasing the process energy efficiency. (Current energy requirements for primary production average 15.18 kWh/kg.) The cost of bauxite is also encouraging producers to explore alternative sources of alumina, such as kaolin.
US Emissions Regulations
EPA's Hazardous Air Pollutant (HAP) regulations cover Hydrogen Fluoride and Polycyclic Organic Matter, both of which are emitted during primary aluminum reduction. These regulations require prevention of emission or re-circulation back into the process of these pollutants using maximum achievable control technology (MACT). According to EPA's Land Disposal Restrictions Program, spent potlining from primary aluminum reduction is considered a hazardous waste due to its cyanide content. There are expected to be additional relevant regulations in the future.
The US demand for recycled aluminum is increasing, which provides incentive to further develop the aluminum recycling industry.
Overall Industry Environmental Goals
Areas of Environmental Focus for Future Research
The Bayer process is used to extract alumina from bauxite into a slurry at elevated temperatures and pressures using a caustic agent such as sodium hydroxide. The main environmental concerns of the Bayer process are its energy intensity and the lack of tolerance to bauxite impurities, such as silica. There are several research objectives for the Bayer process. The first objective is reduction in energy consumption through cogeneration or other innovations. The second is to develop other sources for alumina besides bauxite, such as kaolin. The third objective is to enable operation at higher caustic concentrations, so that higher levels of bauxite impurity can be tolerated.
In the Hall-Heroult reduction process, aluminum is obtained through electrolytic reduction of alumina. First, the alumina is dissolved in molten cryolite in a graphite-lined vat. An electric cell is formed in the vat. The vat serves as the cathode, and a carbon anode is suspended in the cryolite/ alumina mixture. Heat necessary for the reaction is generated through application of a direct current to the cell. Because the reaction requires high temperatures, high quantities of electric power are required. Thus one of the process improvement goals is to develop process options which reduce the quantity and quality of power required. An approach to this is development of an integrated sensor control system for more efficient process temperature control. This also requires development of better process models than currently exist. Another problem is that reactions at the carbon anode produce carbon monoxide and carbon dioxide, creating an incentive for development of non-carbon anodes to eliminate these emissions. A side reaction of the process also produces perfluorocarbons (PFC's), which are global warming gasses, and another process goal is to minimize these gasses' formation. Another side reaction forms cyanide in the cell lining; after the cell has been used, the lining, called pot lining, is considered by the EPA to be a hazardous waste, and another research effort is directed at detoxifying the potlining so that it can be recycled or disposed of more cheaply as non-hazardous waste. Finally, as there are a large number of environmental problems associated with the Hall-Heroult process, finding more environmentally benign alternatives to this process is desirable.
Aluminum recycling has the benefit of reduced energy requirements relative to primary aluminum production. However there are still challenges here. First, with the many aluminum alloys in existence, it can be difficult to separate post-consumer scrap for recycling. Thus, one goal is to improve scrap sorting techniques. Second, a process solid waste - called salt cake (consisting of entrained aluminum metal, salts, and residue oxides) - is considered by the EPA to be a hazardous waste. Thus, a second goal is to develop processes that increase the recyclability of salt cake and/or minimize its production.
The knowledge of the interplay among process conditions, microstructure, and material properties is incomplete. Better process models and better process control could ideally lead to more desirable material properties, and less aluminum required for a given application. Development of improved die casting diematerials that can withstand high temperatures and prevent sticking is also a priority.
Rolling and Extrusion
Again, better knowledge of process conditions, microstructure and material properties is desired, along with better process control. This will facilitate the formation of defect-free surfaces, in addition to overall material properties that are more consistent.
Other Secondary Processes
Another goal is the development of other net shape or near net shape processes which will minimize the necessity for machining and other secondary manufacturing.
Overall, the goal is to develop a systems approach to the steps from alumina production through component manufacture so that system level strategies for reducing overall impacts can be devised.
INDUSTRY - STEEL
Several conditions and trends pose challenges for emissions-associated environmental activity in the steel industry. First, the traditional dependence on coal for cokemaking, steelmaking, and ironmaking leads to high sulfur oxide, VOC, and particulate emissions (among others). Regulations for all of these emissions are increasing in stringency, and this is leading to some movement away from coke and coal in general. Second, there is increasing customer demand for more highly engineered steels, with formulations which contain more precise quantities of alloying and/or coating elements and are less tolerant of impurities. This is a dual challenge for the steel recycling industry because there is now more material variation in process input steel, and there is less tolerance to variation in process output. This, in turn, creates separation challenges and potentially leads to higher levels of waste slag, the disposal of which is increasingly expensive. (Processes generally have three waste products: solid slag, liquid sludge, and particulate dust.) The separation of zinc from galvanized steel is particularly problematic in this context. Finally, the number of process steps, process options, and associated potential waste or by-products lead to challenging system level optimization questions, such as at which process step to separate materials or remove impurities; whether to reduce, recycle, or engineer waste or by-products; and how to balance research effort between improving traditional dirty processes and developing cleaner new processes that may also reduce the number of process steps required. In addition to the emissions-related activities, there is also some work in energy efficiency, particularly in the ironmaking and steelmaking steps.
Figure 2. Steel Manufacturing Process Chain.
Coke production is becoming increasingly expensive due to higher mitigation costs. Disposal of waste residues in all processes is also becoming increasingly expensive and now costs approximately $20 per ton of steel produced.
US Emissions Regulations
Coke oven emissions are regulated under the 1990 amendments to the Clean Air Act. There are emissions standards for Maximum Achievable Control Technology (MACT) and more stringent Lowest Achievable Emissions Rate (LOAR) for oven door and other oven design features affecting source emissions of carcinogens such as polycyclic organic matter and benzene. OSHA also has occupational exposure limits for airborne coke oven emissions. Chlorine and HCl emissions from steel pickling (finishing) are regulated under the National Emissions Standards for Hazardous Air Pollutants (NESHAP). EPA's Title V air permits limit and require monitoring of particulate emissions for all processes. For all steel industry processes, technology based standards for waterborne effluent are established under EPA's National Pollutant Discharge Elimination System (NPDES).
State and Regional Regulations
The Great Lakes Water Quality Initiative has water effluent regulations that affect the steel industry.
20 states have enacted landfill bans for large appliances (white goods), encouraging recycling of the steel contained in these products.
Overall Industry Environmental Goals
Areas of Environmental Focus for Future Research
Coke, produced from coal, is a source of fuel and carbon for blast furnace ironmaking. To produce coke, metallurgical coal is heated at a high temperature in large ovens in the absence of oxygen to remove volatile matter. These volatiles are recovered as gas, tar, or oil, and in some cases are carcinogenic, posing a health hazard to coke oven workers. Typical cokemaking airborne emissions include amonia, benzene-soluble organics (BSO), benzene, particulates, sulfur oxide, and volatile organic compounds (VOC's). One research priority is to shift by-product compositions so that they are more useful and/or less toxic. Particulate matter and sulfur, which are criteria air pollutants, are also emitted from the process. Much of the focus for emissions improvement is on developing better sealed ovens. Improved process control and the associated process modeling, which could lead to more efficient use of energy and better management of byproduct emissions is another research thrust. As cokemaking is generally associated with high levels of toxic emissions, the steel industry is trying to reduce the use of coke.
Ironmaking, the separation of iron from iron ore, is the most energy-intensive process in the production of steel. The output from ironmaking is liquid iron, also called pig iron. There are three methods of producing iron: the traditional blast furnace method, direct reduction, and iron smelting. It is projected that in the next 20 years production will shift away from the blast furnace method, which is currently by far the most common method used. This will reduce the industry's dependence on coke.
There are several areas of research in blast furnace ironmaking. First, one goal is to reduce the energy intensity of the blast iron furnace, and thus its dependence on coke from 840 pounds of coke per ton to 500 pounds. Less coke necessitates more complete combustion, which in turn means coal-oxygen injection systems need to be improved. As the coke is used to structurally support the iron ore in the process, if less coke is used, the coke must be structurally stronger. Better models of the blast furnace process are required to enable further energy use reductions and efficiency improvements. Process waste is also of concern. By-products from the blast furnace include slag, blast furnace dust, and sludge. Slag can be used for landfill construction. Flue dust can recycled to be used as a coolant for steelmaking, though the zinc content must be removed. Sludge is generally disposed of in landfills. Other uses for these byproducts are desired. Because there is a shift to other ironmaking processes, other improvements in the blast furnace method are not considered high priority.
For direct reduction, solid iron is produced from ore or pellets using a natural gas or coal-based reductant. Direct reduction is attractive because it does not require coke. Categories of direct reduction include gas/shaft, gas/fluid bed, coal/rotary hearth furnace or rotary kiln furnace, and coal/fluid bed. Many of these processes are relatively newly developed and not yet well understood. The fluid bed processes do not yet have high enough productivity to be competitive. A better understanding and better models of the processes, along with supporting heat exchanger and gas-distribution system design improvements, will better enable process optimization.
Iron smelting is a relatively new process that produces liquid iron directly from ore fines or concentrate. It is also attractive because it also does not require coke. Coal is generally used as the fuel because of its low cost. However, it does add unwanted sulfur to the process. The COREX process is the one smelting process currently commercially available; however it produces excess thermal energy that must be recycled for the process to be economical. Other smelting processes currently under development include AISI Direct Steelmaking, Japanese DIOS (Direct Iron Ore Smelting), the Australian HIsmelt, the Russian ROMELT, the Hoogovens CCF (Cyclone Converter Furnace), and the Italian CleanSmelt process. Some challenges for the development of these processes include: attaining a sufficient heat transfer rate, developing an efficient pre-reduction process for fines and concentrates, and desulfurization.
Sintering is an iron-making process used to recycle iron-bearing wastes from steel- and ironmaking processes. However, there are numerous emissions associated with this process. Emitted are iron oxides, sulfur oxides, nitrogen oxides, carbonaceous compounds, and chlorides. Increasingly stringent NOx, SOx, and particulate emission regulations are leading to reductions in the use of sintering.
The Basic Oxygen Furnace (BOF) now accounts for approximately 60% of the liquid steel output in the US. The process creates steel from pig iron and recycled scrap in a ratio on the order of 74%/26%. Challenges in scrap usage are identification, separation, and removal of residual elements (such as zinc, tin, and copper). Desired process improvements include better energy efficiency through better process modeling and control. Better process modeling will enable better control of carbon, temperature, slopping (of molten metal), and waste gas composition. One challenge to control system development is the harshness of the furnace environment for sensors. Another challenging area is the management of process waste and its association with process output purity requirements. Process wastes include slag, dust, and sludge. Phosphorus is a particularly problematic contaminant, as lower phosphorus BOF output requirements lead to less in-process slag recycling, which in turn can lead to higher landfill usage rates and associated costs. (When phosphorous contamination requirements are less stringent, iron can be extracted from in-plant recycled slag). Slag can also be recycled outside of the plant. In the past, it has been used for road construction, though this use is declining because of problems created by the slag's causticity. Newer uses include general construction and landfill applications. Some conflicting slag management goals are to reduce its production, to develop alternative uses, and to engineer its chemical content so that it can be more easily used. Developing uses for dust is another goal. Dust can be reused in sintering, if the zinc content is low enough (though the use of sintering is declining due to environmental issues). Researchers are also looking into the possibility of using BOF steelmaking dusts and sludges as raw material in the electric arc furnace (EAF). Another environmental problem is the release of carbon monoxide from the BOF furnace. The process has global warming issues, as it is energy intensive, and carbon dioxide is also emitted directly from the process as carbon dioxide. Water emissions are also an issue. With tightening of water quality standards, particularly in the Great Lakes region, requirements for processing of effluent are becoming more stringent.
The other main steelmaking process is the Electric Arc Furnace (EAF). Much of the research effort for this process has been focused on energy efficiency. Approximately 30% of the required energy is lost as heat to waste gas, cooling water, and radiation, all of which are related directly to heating time; thus much of the energy management effort is directed towards reducing the heating time. There is also some effort to recapture waste heat. Some manufacturers are transitioning from AC to DC to increase the quality of power supplied to the furnace. EAF has traditionally used scrap steel for raw material. This can be problematic. First, the specific alloy content of obsolete (post-consumer) recycled scrap can be difficult to identify specifically enough. Second, the availability of prompt (post-steel product manufacture) scrap is reducing with the increase of near-net-shape metalworking operations. Thus there is some effort to develop methods using pig iron (BOF output) for process input. Process wastes also pose an environmental management challenge. EAF dust can contain high levels of zinc and lead (up to 44% ZnO and 4% PbO), and is classified by the EPA as hazardous waste (K061). The dust is generally recycled back into the furnace for zinc recovery. Slag is created at a high mass rate: for every ton of steel produced, there are about 230 pounds of slag. The primary hazardous constituents are lead, cadmium, and nickel oxides. One method for slag treatment is to remove some iron, so that the remainder has higher zinc content for easy zinc recovery. Generally, about 50% of the iron can be recovered from the slag. Zinc is actually easier to manage in EAF than in BOF, so there is some move to transfer all galvanized steel recycling to EAF.
Ladle refining processes are used to form alloys. Environmental concerns include disposal of spent refractories. Also there are particulate emissions from alloy additions, particulate and sulfur dioxide emissions from ladle refiring and stirring. Suspended solids must be kept to low levels in water effluent.
Home scrap is scrap generated within steelmaking plants. Prompt scrap is scrap generated during the manufacture of steel products. Obsolete scrap is post-consumer scrap. Home and prompt scrap are currently recycled at rates close to 100%, and their generation is decreasing due to increased use of near net shape processing. Only about half of the obsolete scrap is recycled. The major problem associated with recycling obsolete steel scrap is contamination, such as by zinc for galvanized steel. Generally the zinc is removed in BOF's and EAF's, but removing zinc from galvanized coatings (can be 4% of steel) can be accomplished prior to steelmaking through the use of a caustic solution. Recycling steel from household appliances and other products is problematic due to separation difficulties and collection logistic challenges. Also tin-coated steel (used in cans and buckets) can pose contamination problems, as the tin should be removed before steelmaking, and recent developments of thinner tin coatings have made this removal more difficult.
Most of the research effort is directed at continuous casting, as other types of casting are addressed by the casting industry. Recyclability of waste products such as wastewater, spent refractories, and slag, along with reduction of VOC and NOx emissions are the key areas of environmental focus. The fuel cutting torches used to cut lengths from primary ingot in continuous casting of steel or risers from steel castings emit NOx. Steam emissions from quenching at continuous casting operations can contain VOC's. Wastewater from quenching can contain nickel, chromium, lead, and zinc. The EPA is expected to issue stricter regulations regarding these effluents. Sludge is also generated. The sludge contains coarse scale that is easily recycled, and fine particulate and oils, which are generally landfilled. Increasing costs associated with landfill disposal are generating incentives to find alternative uses for the particulate and oils.
Longer lasting refractories also need to be developed. Casting is also moving towards more streamlined defect-free near-net shape processes, so that the cast surface can be a finished part surface, and geometrical tolerances are defined by the end product. Achieving this level of quality requires better models of the process, along with better control of temperature and fluid flow supported by extensive on-line monitoring. Improvements in thin slab and strip casting are expected to reduce the need for hot rolling.
Rolling and Finishing
There is effort to better model the rolling process, so that it can be controlled more effectively and so that surface imperfections and property variation are reduced. The process by-product of milling scale (about 70% iron content) from the rolling process is recycled into sintering, if there is a sintering plant in close enough vicinity. In some cases de-oiling of the material is required. Rolling sludge consists of the fine particles remaining in the rolling cooling water after the mill scale is removed. Recycling of these particles is challenging due to the high oil content. Acid pickling is a finishing process used to clean the surface of hot-rolled steel products. It generates a by-product called spent pickle liquor, which is considered a hazardous waste (KO62) due to its high acidity and heavy metal content. Other cleaning alternatives are being explored.
Refractories used in several processes are of environmental concern at disposal. Thus, there is research on recycling and also means of prolonging their useful life through better design and also repair technologies. Some possible anticipated applications include highway road aggregate materials, ceramic tile raw materials, and abrasives.
INDUSTRY - CASTING
EPA's Compilation of Air Pollution Emission Factors AP-42, Fifth Edition, Volume I: Stationary Point and Area Sources. Chapter 12 Metallurgical Industry http://www.epa.gov:80/ttnchie1/ap42pdf/c12s13.pdf
There are many different types casting process. In each case a permanent or expendable mold is filled with molten metal. Much of the environmental process-oriented focus is on the melting and molding of the metal to be cast, though there is major environmental concern associated with some of the materials used to form the molds, particularly the sand and sand additives used for sand casting and the resin binders. The environmental issues associated with continuous casting are addressed in the steel summary, as continuous casting is generally considered part of primary material production.
Many energy efficiency improvements were developed 20 years ago during the energy crisis. Though energy efficiency can still be improved somewhat, emission management is now the dominant environmental focus. Airborne pollutants, including dust, particulate, off-gases, fumes, and gases (such as carbon monoxide) from furnaces, and other byproduct gases and fugitive emissions, are generally the most costly to control (40% of compliance costs). Management of waste products from casting operations- including waste gases from molding and core making, melting, molding, and shakeout; contaminated and unusable spent sand from sand casting shakeout; slag from melting; and particulate from melting, shakeout, and cleaning-is also costly. The casting industry is heavily populated by small operations oriented towards mitigative compliance; thus there is a deficiency of capital investment in research into new process options and other preventative measures. New technologies and materials are being investigated, however, including non-toxic binders, sand reclamation systems, and air and water purification systems. In addition, metalcasters have been working with some success to develop new alloys that have reduced environmental impact (e.g., alternatives to lead-bearing copper alloys).
From an overall systems perspective, casting also has environmental benefit. First, there is high use of recycled metal scrap in casting (though there are some material separation problems). Of most importance, however, is that near-net shape casting can eliminate the necessity of machining and other secondary manufacturing processes such as joining by combining many components into one.
Energy is estimated to be 15-25% of product cost. Disposal costs are increasing.
US Emissions Regulations
Major environmental statutes and regulations affecting the metalcasting industry include the Clean Air Act (for particulate and hazardous air pollutants), the Clean Water Act (for wastewater for scrubbers and storm runoff), the Resource Conservation and Recovery Act (RCRA) (for spent sand and slag), and the Superfund Amendments and Reauthorization Act (for all solid and liquid emissions containing toxic chemicals).
Stated Overall Industry Environmental Goals
Areas of Environmental Focus for Future Research
Scrap Handling and Preparation
Scrap requires cleaning. Two types of cleaning are used. Solvent degreasing can result in hydrocarbon emissions. Heat cleaning can result in smoke, organic, and CO emission. There are also particulate emissions from scrap handling and preparation.
Melting and Alloys
Melting is the most energy-intensive stage in the casting process. A number of smaller iron foundries have recently converted from cupola melting to coreless induction melting, as it is more efficient for smaller melt requirements. Large iron foundries continue to use cupolas. Melting consists of the following steps: scrap preparation, furnace charging (addition of metal, scrap, alloys, carbon, etc. to furnace), melting, backcharging (addition of more scrap and alloys), refining, oxygen lancing (injection of oxygen), and tapping the molten metal into the molds. Emissions from the melting process include particulates, carbon monoxide, organics, sulfur dioxide, nitrogen oxide, and chlorides and fluorides. Of particular concern is the emission of hazardous air pollutants (HAP's) dioxin and furans from cupolas. There are also trace heavy metal constituents, such as nickel, chromium, lead, cadmium, and arsenic. The highest concentrations of (particulate and fume) furnace emissions occur when the furnace lids and doors are opened. Much of the current effort at reducing these emissions is centered on development of better doors and hoods to capture the emissions.
Systemic improvements will be realized through improvements in process modeling and control, which will enable manufacture of higher quality parts, reducing finishing process steps, and significantly reducing scrap and re-work. Three dimensional shrink factors need to be developed. Process modeling and control needs to be improved. Currently available sand mold continuous process monitoring sensors are inadequate. Modeling of flow turbulence and its contribution to part defects needs to be completed. Also, better models of mold filling and microstructure formation need to be developed. Lack of understanding of induction hardening causes some casters to use less energy-efficient carburizing. Contamination of cast alloys can also occur from the refractory or mold; this can diminish quality.
Environmental and health concerns have led to development of substitutes for lead in copper alloys.
Wastewater from quenching can contain nickel, chromium, lead, and zinc. The EPA is expected to issue stricter regulations regarding these effluents. Sludge is also generated. The sludge contains coarse scale that is easily recycled, and fine particulate and oils, which are generally landfilled. Increasing costs associated with landfill disposal are generating incentives to find alternative uses for the particulate and oils.
Particulates from this process can pose a respiratory hazard for workers. This is particularly true for sand molds containing silica sand (has been associated with silicosis) or seacoal (finely divided bituminous coal added to the mold to prevent mold/metal reactions).
Sand and Binders
The sand from sand casting molds and cores is generally recycled, though the industry is working to develop better methods. Disposing of spent sand can be expensive, as in some cases (especially in casting copper-base alloys) it is considered to be hazardous, and thus cannot be used for landfill. Spent sand is often used to make concrete block and asphalt. Other uses are being researched for the spent sand. Organic binders used in the casting process produce decomposition products, some of which are hazardous.
Aluminum Die Casting
Aluminum die casting poses a different challenge. The dies are made of tool steel, and they must be sprayed with an organic parting agent at temperatures below 230 C to prevent the aluminum from "soldering" to the die. The aluminum is sprayed into the die in a molten state (>700 C). Water is used to cool the die to receive a new application of the parting agent. This thermal cycle is repeated every couple of minutes. Because dies are subject to this thermal fatigue, their lives are relatively short - on the order of 100,000 parts. Up to 2 gallons of liquid (cooling plus parting agent) are used per cycle, and this liquid must be disposed of as hazardous waste. Die coatings to which molten aluminum does not stick (and which have thermal expansion properties that are matched with steel) would reduce both the thermal fatigue of the steel dies, and the liquid waste streams. Further research is also required to develop models of the thermal performance of the dies and the solidification process of the molten metal within the cavity.
The large number of alloys used with no straightforward method for alloy identification makes post-consumer recycling more difficult.
There are a number of overall research goals. First, new process technologies - such as in-process recycling, closed-loop water systems, and low-cost waste treatment technologies - which can minimize or eliminate the generation of certain foundry wastes is considered a priority area for research.
Second, better process characterization and modeling of existing processes would allow the industry to take a more strategic approach to waste management. Third, in cases where waste cannot be eliminated, more extensive research into potential secondary uses, as well as reclamation and separation technologies, would be beneficial. Fourth, development of environmentally benign process materials, such as binders, would also be beneficial. Finally, from a systems perspective, development of better size and dimensional accuracy will reduce the need for downstream processes.
INDUSTRY - POLYMERS
Fried, J. Polymer Science and Technology. Prentice Hall 1995.
Allen, DT. "The Chemical Industry: Process Changes and the Search for Cleaner Technologies," in Reducing Toxics, R Gottlieb, Ed. Island Press, (1995).
Office of Technology Assessment. Clean Chemical Manufacturing Technologies Report, 1995.
EPA Emissions Inventory Improvement Program. Preferred and Alternate Methods for Estimation of Emissions from Plastic Products Manufacture http://www.epa.gov:80/ttnchie1/eiip/ii11.pdf
There are two main categories of plastics: thermoplastics that can be heated and cooled repeatedly, and thermosets, which are cured by heating, and thus are much more challenging to recycle. Common thermoplastics include polyethylene (PET), polyvinyl chloride (PVC), polypropylene (PP), acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), and polystyrene. Common thermosets include epoxy and phenolic. Because both the engineering properties and the manufacturing processes for polymer manufacture are more completely engineered than those for other materials, there is more opportunity to engineer their environmental performance as well. However, deciding where to focus improvement effort can also pose more of a challenge. Industry efforts to improve environmental performance range from replacing petroleum as a feedstock with a renewable material such as lignin - to developing polymer blends with desirable engineering properties which can be produced from recycled polymers. Major environmental concerns in monomer and polymer production include high use rate of solvents, chlorinated compounds, water, and energy. The integrated nature of chemical processes mean that for monomer and polymer production there is potentially great environmental advantage in applying a system approach to process development. Plastics processing (molding, extruding, etc.) generally requires large amounts of externally applied energy, though there are some recent innovations such as reaction injection molding, in which the plastic is intrinsically heated via an exothermic reaction. Plastic recycling is challenging due to the large number of polymer formulations and additives, and also because the polymer molecules degrade as they are reprocessed. Also thermosets, which are commonly used in engineering applications, particularly in the electronics industry cannot be recycled.
Figure 3. Polymer Manufacturing Chain.
The polymer industry is highly dependent on fossil energy, both for fuel and for feedstock. This can account for up to 85% of production costs for some polymers. The cost of abatement measures have doubled since the mid 1980's. The chemical industry accounts for 75-90% of hazardous waste generated in the US, and disposal costs are increasing.
US Emissions Regulations
Chemical production, use, storage, transportation, and disposal are regulated under the Clean Air Act (CAA), the Toxic Substances Control Act (TSCA), the Resource Conservation and Recovery Act (RCRA). These regulations are increasing in stringency. Monomer production, polymer production, and plastics processing can all result in VOC and HAP emissions.
The chemical industry is responsible for a large proportion of total toxic release inventory (TRI) emissions, making it a target for environmental groups. Partially because of recycling challenges, polymers have a poor environmental reputation among some segments of the public.
Overall Industry Environmental Goals
-- none cited because this summary is based on a compilation of sources rather than a roadmap.
Areas of Environmental Focus for Future Research
Monomer / Polymer (Resin) Production
Monomer and polymer production have their foundation in the chemical industry. Like other industries, the chemical industry must manage solvents, heavy metals, chlorinated compounds, high water use, and other wastes. Process efficiency increases and better water and solvent recycling are key process improvements. It is particularly important to take a systemic view to process improvements in the chemical industry, as process by-products, such as HCl in the production of vinyl chloride, are commonly used as raw materials in other processes. Traditionally polymers have been made from petroleum, but there has been recent effort to increase use of renewable feedstocks, such as lignin (which is a by-product of the kraft paper pulp-making process).
Solid Plastics Forming
Plastic products are formed by applying heat and/or pressure to one or a combination of resins and then injecting the liquid into a mold or die. Additives, such as plasticizers, antioxidants, flame retardants and/or colorants can also be added. Some of these additives, such as brominated flame retardants, can pose health hazards. Common processing methods include extrusion, injection molding, blow molding, and foam processing. Due to the high levels of thermal and/or mechanical power required, these conventional forming methods are energy intensive. Recently-developed reaction injection molding in which 2 liquid plastics (such as polyols and isocyanates) are mixed, resulting in an exothermic reaction. This substantially reduces energy requirements. Emissions of concern from molding and extrusion include volatile organic compounds (VOC's) and/ or hazardous air pollutants (HAP's), which result from the volatilization of monomers, blowing agents, or lubricants. In addition VOC's, HAP's, and particulates can be formed through chemical reactions which occur during heating of the resins. The rate of production of the undesired by-products is generally reduced for processes occurring at lower temperatures (near the melt point for the resin). A more thorough understanding of forming processes is needed and better emission preventative strategies and/or mitigative containment systems should be developed.
To manufacture foam plastics, a blowing agent (such as methylene chloride or chlorofluocarbons) is used. These blowing agents commonly result in emissions during product manufacture or product use. As easy volatilization can be an important functional property of the foaming agent, emissions can be particularly high. Work is needed to devise ways to reduce the quantity of agents needed and to improve methods for recapture.
Lamination and/or coating is used to apply a polymer to a surface. Lamination involves the following three steps: bath dip impregnation, oven drying, and high temperature pressing. Two main types of coating are drip coating and roll coating. After coating, the part is air dried or baked. Solvents used to clean the lamination or coating equipment commonly lead to VOC emissions.
Polymer recycling is challenging for several reasons. First, production of plastics from recycled feedstock is typically on the order of 20% more expensive than virgin production. Second, thermosets, which cannot be recycled, account for a significant fraction of polymers. As polymers are generally more difficult to separate than metals, mixed polymers are often recycled into secondary applications. Another approach is to chemically convert plastics back into their monomer constituents, so that recycling back into the original polymer can occur. However, this is more energy intensive. Engineering polymers are often more difficult to recycle because they can be logistically difficult to collect in post-consumer waste streams as they form a low proportion of overall polymer waste. Furthermore, their properties are more precisely engineered, making contamination and formulation inconsistencies more problematic. Removal of paint and other coatings is challenging.
As polymers are manufactured from petroleum feedstock, they have a high energy content (on a mass basis, on the order of twice that of coal). Burning them for energy is one post-use option. However, any heavy metal content, such as cadmium, will be contained in the ash. Also, the incineration of chlorinated plastics, such as PVC, can result in the production of dioxin, a carcinogen.
Biodegradation is another option to address polymer end-of-life. The polymer may, itself, be biodegradable (such as some naturally-occurring polyesters), or a biodegradable additive, such as starch, may be used. The challenge here is to engineer the polymers so that they degrade when desired (in a landfill), but have consistent performance during use. Also, as biodegradable polymers are generally not recyclable, they must be separated from the recycling stream.
INDUSTRY - AUTOMOTIVE
NSF/DOE Basic Research Needs for Environmentally Responsive Technologies of the Future. (1996), Princeton Materials Institute.
EPA Project Summary: Mobile Onsite Recycling of Metalworking Fluids. EPA/600/SR-93/114,
National Center for Environmental Research and Quality Assurance. Characterizing Risk at Metal Finishing Facilities http://es.epa.gov/ncerqa/pub/csidoc.html
Automobiles are complex, material-intensive products. Automotive components are manufactured by many different suppliers. With such complexity, it can be difficult to prioritize the areas for manufacturing improvement. A method that has been adopted by the industry is to apply an assessment methodology such as LCA to highlight problematic processes and prioritize manufacturing steps for environmental improvement. Airborne hazardous emissions are concentrated in painting and coating processes. Improving the performance of powdered paint so that it can be used more extensively will reduce the impacts associated with vehicle painting. The process generating the highest volume of solid waste is casting. Thus there is effort to develop more options for recycling and re-use of sand-based casting molds. Aluminum die casting is a large source of wastewater, and technology can be improved here. Production of vehicle glass is the process associated with the highest per vehicle energy consumption so improving this process is also a priority. There are also other process improvement efforts in sheetmetal operations, welding, plating, and cutting fluid use reduction. Increased recycling is another goal that can be attained by improving material separation technologies and/or reducing the quantity and incompatibility of distinct alloys and polymers contained in a vehicle. Finally because there is a drive to increase vehicle fuel efficiency and therefore decrease vehicle weight, there is interest in increasing the use of aluminum in cars, which necessitates some aluminum manufacturing process development in casting, machining, and welding.
Hazardous waste disposal
US Emissions Regulations
CAA, CWA, RCRA, CERCLA, SARA, AEA, OSHA, Hazardous Materials Transportation
Overall Industry Environmental Goals
Areas of Environmental Focus for Future Research
Iron foundry casting sand wastes contribute the largest volumetric quantity of solid wastes in the automotive industry (1.5 million tons/ year). Used foundry sands contain organic binders and heavy metals that could leach out upon disposal, and thus they are considered hazardous waste. Thus, it is a priority to develop new uses for spent foundry sands and/or new casting methods that utilize a different reusable or recyclable material. Aluminum die casting is associated with high levels of fluid waste. Improvements in die coatings will reduce the quantity of parting and cooling agents required. A third area of focus in metal casting is in development of better near net shape technologies so that downstream joining and machining processes are unnecessary.
Automotive glass manufacturing is the process with the largest per vehicle energy consumption. When the glass has to be remelted due to defects, this requires large amounts of energy and results in significant NOx and SOx emissions. Composition and coating improvements along with improved process control can reduce the quantity of manufacturing pieces rejected and thus reduce overall energy consumption. Tempering (putting the glass surface in a compressed state to improve fracture resistance) is one process that particularly needs process modeling development, as windshields that are improperly tempered must be rejected.
Automotive Painting/ Coating
Painting is the manufacturing process that results in the largest per vehicle emissions of Volatile Organic Compounds (VOC)'s and Hazardous Air Pollutants (HAP)'s. Historically, the problem was more severe, as oil based paints were used. However, even today's water-based paints do contribute to volatile emissions. Powder paint has a number of advantages over oil- and water-based paints. It does not result in hydrocarbon emissions. It does not require the use of solvents. Unlike conventional liquid paint for which waste must be disposed of in landfills (about 20 pounds per car), powder paint that does not adhere to the vehicle can be reused. The one drawback of powder paint is surface quality. Research which would lead to improvements in powder paint technology include development of an understanding of the optimal particle size distribution, development of models for the rheology of small particles, development of models for dry particle attachment to surfaces.
Historically, heavy metals such as Cr and Ni have used as appearance coatings, such as in chrome bumpers. These metals are applied through a plating process in which the part is immersed in a series of baths. Metal plating facilities can release a variety of toxic compounds. Chlorinated hydrocarbons are emitted during pre-cleaning (degreasing) of metal parts; and caustic mists, cyanides, and metals are released from the actual electroplating process. Hexavalent chromium, a carcinogen, is of particular concern for worker and public exposure. Development of better emission containment and recovery are priorities here for existing processes. Also, research needs to be completed into less hazardous appearance coating materials.
Sheet Metal Operations
Current manufacturing processes result in significant scrap production. For example, for stamping processes, typically 40% of metal ends up as scrap. Thus, research is needed into sheet metal forming processes that will reduce scrap production. Requirements for higher vehicle energy efficiency are leading to greater demands for lighter aluminum, but primary aluminum production is much more energy intensive than steel production. However, the use of aluminum does enable the use of superplastic forming (which reduces scrap production) as an alternative to conventional sheet metal forming.
Metalworking Fluid Management
Metalworking fluids are commonly used for lubrication and cooling in machining operations. Metalworking fluid mists are associated with occupational health hazards and the fluids' disposal cost is high. Degradation and therefore rate of disposal can be accelerated by the addition of thermal energy through machining and the addition of contaminants and/ or tramp elements which support the growth of bacteria. Thus, there is incentive to reduce mist formation and improve fluid hygiene and management procedures. Research priorities here include development of better mist filtering systems and other mitigation equipment, development of fluids that are less prone to aerosol formation, and development of fluids and fluid management strategies that reduce the rate of fluid degradation and disposal. The development of better fluid recycling technologies is also a priority.
Dry Machining of Aluminum
Another approach to reducing the environmental problems associated with cutting fluids is to stop using them. Because cutting fluids require fluid delivery and collection systems, not using the fluids can also decrease support and maintenance costs. Thus, there is interest in reducing the fluids' use. There is work in the dry machining of aluminum which focuses on the development of new cutting tools which are less dependent on the cooling and lubricating properties of cutting fluids, and the development of optimal fluid-less systems for chip flow management.
Improved Welding Technology
Resistant spot welding is the predominant means of joining sheet metals in auto body manufacturing. There is a desire to improve the quality and consistency of the welds, so that fewer welds will be required (the aim is to reduce the quantity of required welds on the order of 10%), resulting in reduced energy consumption. As part of this effort, analytical models are being developed of weld formation. These models will be used to develop spot welding machine control systems. In addition welding technology for aluminum needs to be improved.
The main challenges in automotive recycling are first the impurities in aluminum and steel due to alloying elements. This problem could be reduced through scrap sorting, in-process impurity reduction, or simply a reduction in the number of distinct alloys used in automobiles. The separation of mixed (and painted) plastics is the second problem. Currently very little of the plastic contained in vehicles is recycled. Thus, there is some effort to find recycling processes for plastics and rubber that are cost effective. This effort includes developing more cost-effective infrastructure. There is also some effort to improve separation processes, particularly to enhance recyclability of windshields, which are made of Polyvinyl butyral (PVB)-laminated glass.
INDUSTRY - ELECTRONICS and COMPUTER MANUFACTURING
Steven W. Pedersen, "Electronics Industry Environmental Roadmap", IEEE Symposium on Electronics and the Environment, Conference Proceedings, Orlando, FL, May 1995, pp. 285-289.
The electronics industry aspires to a proactive approach to its environmental activities. The industry aims to work with regulators and standard-setting organizations to develop rules and guidelines that are more flexible and more globally consistent. The industry also recognizes the importance of different levels of decision-making, and has given priority to the development of design for environment tools, supply chain management guidelines, and environmental management systems.
Environmental areas of focus for the industry include reduction in the use of hazardous solvents and other chemical agents through agent reuse or manufacturing process substitution, decreased use of water, and increased component reusability and recyclability.
EPA Voluntary Programs/ Regulations
According to the MCC roadmap, the electronics industry prefers to focus on EPA's voluntary programs rather than compliance-based regulations. The Common Sense Initiative (CSI) encourages development of pollution prevention programs and innovative environmental approaches. The Environmental Leadership Program (ELP) focuses on development of environmental management and communication.
State and Federal Regulations
Compliance-based regulations relevant to the electronics industry include the Clean Air Act, Clean Water Act, Resource Conservation and Recovery Act, Superfund and Emergency Planning and Community Right to Know Act and Toxic Substances Control Act. State level toxic use reductions are also relevent.
European and Japanese take-back initiatives
There are emerging product take-back regulations in Europe and Japan leading to increased efforts in design for end-of-life.
Miniaturization is a natural trend in the electronics industry and is also inherently beneficial to the environment. Reductions in hazardous waste yield savings in cost of disposal.
Overall Environmental Goals
Areas of Present and Future Research
Semiconductor (Integrated Circuits) Manufacturing
The Semiconductor Industry Association (SIA), in association with its member companies, SEMATECH and the Federal government have developed a set of environmental priorities. One priority is use reduction of ozone-depleting substances and hazardous solvents. Emissions abatement technology and replacement chemicals are being sought for persistent compounds, such as perfluoro compounds (PFC's). Another priority is to develop tools to manage chemical, energy, and water mass balance; ESH cost of ownership; and risk assessment. Development of better process models and development of better process sensors will enable development of better control systems.
Integrated Circuit Packaging or Electronic Packaging Manufacturing
IC packaging is the process of encapsulating integrated circuits so that they may be reliably interconnected onto electronic systems. Leadframe production (construction of a rectangular metal frame with leads) is the first step. This process requires a solvent after punching of registration holes. In the past, chlorinated fluorocarbons were used, but the industry is shifting to aqueous cleaning. Shrinking IC size is leading to an increase in etching to produce very fine leads. The leadframe is masked using a liquid photoresist or an aqueous dry-film. The latter is generally environmentally preferred because it does not require the use of trichloroethylene (TCE) for removal and does not result in VOC formation. The leadframe is then plated using metals such as nickel and palladium. The processes of environmental concern in leadframe production are plating and cleaning.
The selection of packaging material from the various options also poses environmental challenges. In general, ovens, which are required for curing, consume much energy. Ceramic packaging, the choice for small batches because it does not require design and manufacture of molds, requires more chemicals (including hazardous organic solvents such as toluene, xylene and binders such as polyvinyl butyral) and consumes more energy than plastic. Plastics are an attractive alternative for larger batches. However, presently thermosets dominate packaging materials. Because themoset resin cannot be reused, up to 60% of the material is wasted. In thermoset packaging types, hazardous epoxies, heavy metals, and flame retardants (often brominated furan) are used. Thermoplastics, such as polyphenolene sulfide, can be reground and reused. Also, as they do not require a post-mold curing step, their use can result in significant energy savings. However, they are more expensive and more hygroscopic than thermoplastics. Reaction-injection molding based on styrene is another plastic alternative that offers the advantages of thermoplastics. Punched metal packages are an alternative to ceramic and plastic that is presently being explored. The main environmental goals in packaging are to reduce the use of hazardous cleaning agents through the development of alternative cleaning technologies and the elimination of unnecessary cleaning steps, to find less toxic flame retardant materials, and continue to improve the environmental performance of packaging materials and processes.
Printed Wiring Boards (PWBs) and Assembly
PWBs are foundations upon which most electronic products are built. The boards provide the electrical pathways for device connectivity and also support the devices. From environmental standpoint, they share many of the same type of issues as IC packaging. These include agents used for etching, stripping, developing, plating and cleaning. More recent research focuses on integration of environmental information into the physical design of the boards through the use of DfE tools. Lead, a constituent of the solder used to affix the components on the boards, is another concern, both for worker health hazards and for potential public exposure to groundwater contaminated by landfill leaching. Lead-free soldering alloys like CASTIN are in the development stage and it will be some time before these alloys are extensively used commercially because of reliability and performance concerns.
Displays and Enclosures
Displays are generally based on traditional cathode ray tube (CRT) based technology, although there has been an increase in the number of liquid crystal displays (LCDs) or flat panel displays (FPDs) in use. CRTs represent significant environmental challenges, primarily in disposal due to high material volume and lead content. The lead is currently required in the glass for structural reasons. Improvements in recycling infrastructure and material development innovations leading to a reduction in lead content are the two main goals here.
Manufacturing environmental priorities for FPD's include development of cost-effective component recycling and reuse, and recovery of spent process chemicals and solvents, such as glycol ethers and PFC's, Use phase environmental priorities include reduction in use phase power consumption and extension of useful life through increased durability and serviceability.
With product take-back laws in Asia and Europe, there is increasing focus on electronic product end-of-life. There are many different aspects of electronics product end-of-life for which research is needed. First, at the process level, better separation technologies are needed, particularly in plastics. Particularly challenging are difficulties in polymer ID and sorting, separation from metallic and paint coatings, and separation of mixtures containing plastics, rubber, and glass. In order to better facilitate separation there is effort to design products so that they are more easily disassembled and recycled. The effort here centers on reducing the number of different types of materials used, using easier to disassemble fasteners, grouping compatible materials in the same subassembly, and making components of value easily accessible. Developing strategies for recovering components with value versus recovering materials is another research thrust. Recovering components is generally more costly, as it must be done manually, so for lower value components, it may not be cost effective. As computers are generally disposed of when their components are still relatively new, this research area is particularly applicable for computers. Another important area is development of logistical systems for product recovery and entry into the recycling stream. Finally, there is effort to use recycled polymers in electronic products. In some cases this means developing blends of different polymers which meet performance specifications and aesthetic requirements.
INDUSTRY - MINING
Mining encompasses all activities, techniques and methods to extract all non-fuel minerals and coal. Modern mining is a highly sophisticated industry. Computers, microprocessors, sensors and satellite communication are responsible for making big machines efficient and reliable and adapting to new competitive environments in a safe and environmentally sound manner. For example, remote control of hauling equipment and the use of autonomous mobile transportation equipment is increasing worker safety while at the same time reducing industry costs. The demand for some metals and industrial minerals is growing due to changes in the automotive, telecommunications, and plating industries. For example- the consumption of zinc is now increasing, after years of decline, because its use as an anti-corrosive coating for metals has grown. Copper, with its high degree of conductivity and relatively low cost, has an opportunity to expand its markets. High efficiency motors, for example, contain larger volumes of copper. Copper is also becoming the metal of choice for high performance integrated circuits. Gold's corrosion resistance and high conductivity make it an essential component in the growing market for sensitive electronics and other advanced products. There will be an increase in the demand for lead if battery driven vehicles penetrate the transportation market. Today the minerals industry alone is a $39.5 billion industry. Total mine production for coal is estimated to be valued at about a $19.9 billion, for metals about $12.4 billion, and for industrial minerals about $27.1 billion. Also, there is an estimated $2.1 billion of processing equipment developed and shipped annually to support mining operations.
Energy cost is about 5% of the value of commodities produced.
Mining imparts a large burden on the environment because of the high energy consumption and intensive processing involved. Steps such as the handling and disposal of waste and products containing metals, long range transport of air pollutants, and agreements related to other environmental concerns are needed to address the global environmental concerns and issues. The mining industry must respond to climate change strategies through advanced research and testing, including: improvements in energy efficiency, methane emission control, reduction of carbon use, and carbon dioxide sequestration. Mining operations result in acid mine drainage and metal tailings flowing to the land, air and water. This calls for research in efficient mining operations and processing and efficient use of mined products.
Safety and Health
The mining environment can be harsh; exposure to radon, uranium, coal dust, and other types of rays, dust, and chemicals can be harmful to humans in those environments. Also, the equipment used to explore, mine, and process minerals is powerful and can be dangerous when used improperly. Training and education need to be emphasized across the industry, and new types of equipment for ventilation and protection need to be developed to keep miners healthy and safe. Improved personal equipment and safety technology used by miners, new sensors and controls, and new miner training programs are essential to the well being of the miner of today and tomorrow.
The US mining industry consumes about 1 to 2 quadrillion BTUs annually. The Energy Information Agency (EIA) indicates the mining industry consumes 3.2% of the total energy used by all industries. Significant efficiency gains could be obtained by improving exploration techniques, drilling, ventilation, excavation, and extraction technologies and in beneficiation, grinding, crushing, milling, rolling, and smelting processes. The goal to consume less energy per ton of ore mined and processed remains a key objective of the mining industry.
Overall Environmental Goals
Areas of Future Research
The research needs identified by industry as critical to overcoming the barriers to safe and efficient mining are organized into five categories: Mining Equipment, Mining Process, Sensors, Mine Planning and Health and Safety
Alternative Power: The ongoing research in this area includes the development of new fuels and fuel strategies for the mobile equipment. Currently most of the mining equipment runs on diesel. This results in air and noise pollution. Alternatives to diesel such as fuel cells are being developed. However they are not particularly energy efficient. Hence, research is needed in the area of cost-effective, low noise, low-emission, efficient sources of power for the equipment.
Material Handling Techniques: The long-term research plans include the development of radically new ways of material handling. E.g. More efficient technologies for removing rock and coal involves developing 'exotic' mining techniques that utilize very different ways of cutting, drilling, or moving rock in mining, as opposed to incremental improvements to existing technologies. This research would produce 'next generation' rock removal technologies that would help achieve the performance targets related to mine output/ productivity and energy and materials efficiency.
Process Modeling and New Techniques: The planned research in this area related to the environmental impact includes understanding and accurately modeling the processes to predict the emissions, reprocessing the mine waste to recover the saleable byproducts and developing the blasting techniques to minimize noise, dust and flying rock.
Cleaning and Separation Technology: Two of the highest priority R&D needs -- new materials for phase separation and improved separation and cleaning technologies, including de-watering, water treatment, and byproduct management and utilization -- address the performance target of improved separation efficiency. Examples of this include new materials for ion exchange, new membrane materials for filtering etc. These two proposed R&D activities also contribute to the goal of improved byproduct management and utilization, specifically through the reduction of effluents and waste. A positive environmental impact can be expected because separation and cleaning processes are normally used for environmental remediation, and could result in more usable materials from waste.
Material Utilization: Although the development of breakthrough separation and cleaning technologies could lead to major cost savings, continuous incremental improvements may have only moderate cost-savings potential. A long-term vision for the industry would find constructive use for all material removed in the mining process.
The future research includes the development of sensors to better monitor the workplace conditions thus improving the worker safety in a hazardous work environment.
The planned research in this area includes development of predictive geological models to better understand the rock mechanics and rock structure. This would result in more efficient mining process resulting in energy savings.