Besides technical aspects, wide acceptance of reusing foundry solid wastes as marketable materials will only be achieved by removing barriers or limitations arising from public perception (education or training), environmental regulation, engineering guidelines and procedures, economics, and market potentials. These barriers are basically nontechnical but take considerable efforts to address. Unlike the technical aspects of a reuse program, many parties are involved, such as the government, the public, academics, and industrial and commercial departments. A coordinated and consistent framework needs to be constructed among these parties, aiming at eliminating barriers to the foundry solid waste reuse program.
Public acceptance of foundry waste reuse significantly depends upon their understanding of nature and the performance of foundry waste materials and generated products. In general, negative descriptions, such as its black appearance, the presence of casting byproducts and heavy metals, high melting temperature and sometimes odor, may automatically bring objections into the public mind. It is unfair. The public should be well educated to understand the generation and characterization of foundry solid waste. Documented technical data and environmental regulations are to be presented to convince people that foundry solid waste (at least not all) is not hazardous or as bad as they thought.
Communication channels shall be set up between industry and academics. There has been inconsistency with regards to the characterization of foundry solid waste between industry and academics. The former cares about the workability and efficiency of materials in generating products. The latter concentrate on the technical behavior of materials if reused. The way that metal casters define the characteristics of their sands is completely different from what the contractor wants to know. For example, metal casters talk about ground fineness number, whereas contractors want to know fine and clay contents. At the point of reusing their solid waste, metal casters should divert their attention from regulators and customers to researchers, working within a well channeled system.
Solid waste regulations are frequently cited as barriers for metal industrial byproduct recycling. Research indicates that most ferrous spent foundry sand meets nonhazardous standards under the
RCRA. Competing granular materials, such as sands, gravels, and native soils, are not regulated materials although their environmental profiles may be similar to spent sands.
In some case, experts may debate the reuse of nonhazardous materials, which, they insist, should still be dumped to general landfill sites where nonhazardous materials belong, like municipal solid waste. It is also insisted that there is no documented regulation requiring the reuse of nonhazardous materials. Therefore, to defend the beneficial reuse program of foundry solid waste, regulations should specifically permit their marketing.
Environmental regulation should be complied with to legally validate a reuse program. It is critical that recyclers become familiar with the federal and state regulations relative to their materials. Before reuse starts, materials should be tested according to these environmental regulations to determine whether they are hazardous or nonhazardous. Knowing and understanding the rules and regulations will lead to a better reuse program.
4.5.3 Guidelines, Procedures, and Specifications
Conventional materials have been approved to enter the market, supported by many standalone guidelines, procedures, and specifications. As such, suppliers and users favor the selection of conventional materials. Foundry solid waste is being put to a competitive disadvantage against conventional materials, just because no standalone guidelines and procedures are universally documented for their potential markets. This barrier could be eliminated by showing data demonstrating that foundry solid waste is at least as good as, if not better than, conventional materials for target end-uses. A trial and error procedure is normally used in bench-scale tests, where guidelines, procedures, and specifications are developed by referring to documented ones. Successful experimental and field demonstration then further modifies and finalizes guidelines, procedures, and specifications.
Economical factors, such as disposal costs, the availability of conventional materials, and transportation costs, are critical considerations. As with any material, transportation costs are generally the highest cost factor in recycling solid waste. The most economically sustainable options for recycling foundry solid waste will generally match the volume and characteristics of the materials with nearby businesses and construction projects. Small foundries may not generate enough material on a weekly or monthly basis to satisfy the need for construction sands. In this case, it may be necessary to collect similar wastestreams from multiple sources or to partially substitute for conventional materials in order to meet volume requirements.
Some end-use applications may prefer the characteristics of foundry solid waste. For instance, spent foundry sand is a uniformly graded fine aggregate containing chemically active iron and organics. Spent foundry sand can be superior to other types of granular materials, such as compacted soils or clays, for hydraulic barriers. In this case, spent foundry sand provides better performance at lower cost.
One particular mistake that foundries make is improperly defining the market potential of their byproducts. Competitive material availability and transportation costs will dictate market acceptance in most cases. They must study the landscape before attempting to enter the market. Active marketing efforts will always get paid back. Keep in mind that many potential customers are cost-conscious, and that is an advantage to the foundry byproducts process. Aiming low to establish a market is a great strategy for getting in the door. Foundries need to value market sustainability and cost reduction over the best short-term deal. Build partnerships with end-users and long-term progress will be established.
Before entering the market, the following questions should be addressed in order to have a good start. The ultimate goal is that the bottom line of reuse is well understood, making sure the materials are characterized properly, and then marketing them according to the appropriate regulations.
1. Is the volume of material supplies adequate for the quantity expectations of a potential customer?
2. Will the properties and variability of the materials satisfy the quality expectations of a potential customer?
3. Will any processing be required to consistently guarantee the expected quality level?
4. Is all cost taken into account?
5. What is the cost of the material the byproduct is to replace?
6. Are all permits obtained for the actions?
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