(Thanks to the American Foundry Society for this 2005 Paper #05-125 "Significant Reduction in the Emission Characteristics Of the Green Sand Metalcasting Foundry Process." We've shared selected highlights on the paper. Go to the paper online here or download a copy here.)
By Victor S. LaFay, Hill and Griffith, Cincinnati, OH; George R. Crandell, Technikon, LLC, Scaramento, CA; Clifford R. Glowacki, CIH, Technikon, LLC, Sacramento, CA; and Steven M. Knight, Technikon, LLC, Sacramento, CA
Table of Contents
3.0 Investigations That Contributed To Final Test Evaluation...11
3.1 Contribution of Green Sand Emission Characteristics without Seacoal and
3.2 Contribution of Mineral Additives into the Prepared Core sand and the resulting
4.0 Test Evaluation Utilizing Information from Previous Studies ...15
6.0 Casting Quality...19
List of Figures
Figure 1 Osborn Molding Operation...11
Figure 2 Star Castings (4 on pattern)...11
Figure 3 Individual Star Casting...11
Figure 4 Green Sand Release Agent on Pattern...12
Figure 5 Release Agent (Transferred) on Mold...12
Figure 6 Emission Characteristics of Green Sand Release Agents...12
Figure 7 Osborn Pattern...13
Figure 8 Sample Core containing Additive...13
Figure 9 Mold containing Cores...13
Figure 10 Step Castings Produced...13
Figure 11 Emissions Characteristics of Core Sand Additives...14
Figure 12 Prepared Molds and Cores...15
Figure 13 CERP Testing...15
Figure 14 Emission Results Summary from Test Mix vs. Selected Baseline ...17
Figure 15 Target Analyte Emission Results from Test Mix vs. Selected Baseline...17
Figure 16 FK001 Best Casting Surface...19
Figure 17 FV005 Best Casting Surface...9
Figure 18 FK005 Median Casting Surface...19
Figure 19 FV008 Median Casting Surface...19
Figure 20 FK004 Worst Casting Surface...20
Figure 21 FV011 Worst Casting Surface...20
List of Tables
Table 1 Testing Parameters...10
Table 2 Core Sand Additives and Addition Rates ...14
Table 3 Process Data Comparison ...16
Table 4 Comparison of Emission Results...16
As a result of the metal casting process, emissions are generated by the thermal decomposition of organic material in the greensand and, if cores are present decomposition of the core binder. Through changes in the blended minerals in the green sand molds, the addition of minerals to the prepared core sand, and selection of the green sand release agents, significant reductions in VOCs, HAPs, carbon monoxide, and carbon dioxide emissions can be accomplished. This reduction in emissions has been determined during actual metal casting with advanced analytical methods and equipment that have been developed by Technikon for the Casting Emission Reduction Program (CERP) in Sacramento, California.
During the last ten (10) years, a number of development studies have been completed at various foundries, technical centers, universities, and research facilities on the emission characteristics of foundry processes (LaFay, Neltner, April 2002). For this particular investigation, a series of studies has been completed at Technikon, which operates CERP, that supplies valuable information that was utilized to develop the significant reduction in the emission characteristics of the green sand process. These studies review the characteristics of the emissions that were the result of the metal casting process from the green sand, green sand release agents, contribution of the emission characteristics from the core process (and the subsequent return of the core material into the green sand) and the greensand release agents. Each one of these processes contributes uniquely to the emission characteristics, so they were investigated individually. Table 1 summarizes the test protocol used for the development of a baseline data set that was used to evaluate the emission reductions from the greensand/core/mold release system being tested.
The results from the evaluation of this new greensand formula (without seacoal), phenolic urethane cores with additives and pattern spray with graphite show that: 1. Casting surface quality is comparable to that achieved with a traditional greensand with seacoal. 2. Volatile organic compounds as measured by US EPA Method 25A were reduced by 51%. 3. Hazardous air pollutants as measured by US EPA Method 18 were reduced by 42% 4. Carbon monoxide emissions were reduced by 37%, and 5. Carbon dioxide emissions were reduced by 40%. Overall, the data clearly show that significant emission reductions can be achieved without sacrificing casting surface quality.
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