Recovery of Waste Polymer Generated by Lost Foam Technology in the Metal Casting Industry

EPA Grant Number: R825370C074
Subproject: this is subproject number 074 , established and managed by the Center Director under grant R825370
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: EERC - National Center for Clean Industrial and Treatment Technologies (CenCITT)
Center Director: Crittenden, John C.
Title: Recovery of Waste Polymer Generated by Lost Foam Technology in the Metal Casting Industry
Investigators: Pletka, Jeremy , Drelich, Jaroslaw
Institution: Michigan Technological University
EPA Project Officer: Klieforth, Barbara I
Project Period: January 1, 1997 through January 1, 1999
RFA: Exploratory Environmental Research Centers (1992) RFA Text |  Recipients Lists
Research Category: Center for Clean Industrial and Treatment Technologies (CenCITT) , Targeted Research

Objective:

It is desirable to recover expanded polystyrene and dispose of only coating and glue components from scrapped lost foam patterns produced in automotive manufacturing. Although it is not an objective to circulate recovered polystyrene back into lost foam casting it is desirable to reclaim polystyrene of sufficient quality to return to the consumer market. Therefore, it is the goal of this project to develop a simple, inexpensive technology for the recovery of expanded polystyrene with a minimal amount of contaminants for further use.

Approach:

This research program was initiated to assist the metal casting industry in prevention of polymer waste disposal, and to promote engineering solutions leading to reuse of the polymer. In the automotive casting industry, lost foam casting is a process in which a polystyrene pattern is formed into the desired shape of the part to be cast. More complex parts are fabricated by simply gluing several pattern pieces together. The final pattern is then coated with a refractory material consisting of a mineral mixture and binders. Hot metal is then poured into the patterns, evaporating the polystyrene, and taking shape of the mineral coating shell.

Inevitably, pattern fabrication introduces a waste stream as a result of subsequent handling or from degradation of the casting in storage. The damaged patterns are not reusable, creating a potential disposal problem, as lost foam casting is becoming more prevalent in the automotive casting industry. The potential volumes of scrap therefore prompt the development of an effective, inexpensive technology for the recovery of the recyclable material (polystyrene) as an alternative to waste disposal.

Our strategy adapts the principles of modern mineral processing technology to polymer recovery. The two-year program includes particulate characterization, examination of surface-interfacial properties of the pattern components, development of an analytical technique for contaminant concentration measurements, shredding and size reduction, and selective separation testing based on component density.

Additionally, in the initial phase of the program we observed that component separation based on size compliments density separation, and therefore our approach also includes a fundamental investigation of component size segregation resulting from rotary shredding and impact comminution.

Investigation of component size segregation, impact comminution, and initial separation tests have yielded positive results. It was observed that almost complete release of coating from polystyrene occurs during shredding with a rotary blade shredder allowing for differential size segregation of the components. Shredded material was first screened and next separated by density using float-sink or cyclone testing. Separation testing recovered as high as 98% of the polystyrene, while the level of coating contaminants did not exceed 5%wt in the final product.

Additionally, impact comminution has succeeded in decreasing the coating contamination level to 2%wt. These experiments have indicated that an extensive investigation of a separation process based on component density and size is justifiable and will be continued in the second phase of the project.

Expected Results:

It is anticipated that this research program will assist the metal casting industry in prevention of polymer waste disposal, and this project will promote engineering solutions leading to reuse of the polymer.

Publications and Presentations:

Publications have been submitted on this subproject: View all 2 publications for this subprojectView all 157 publications for this center

Supplemental Keywords:

technology for sustainable environment, environmental chemistry, clean technology, environmental engineering, pollution prevention, cleaner production, metal casting, polymer waste disposal, waste minimization., RFA, Scientific Discipline, INTERNATIONAL COOPERATION, TREATMENT/CONTROL, Ecosystem Protection/Environmental Exposure & Risk, Sustainable Industry/Business, Chemical Engineering, cleaner production/pollution prevention, Sustainable Environment, Environmental Chemistry, Technology, Chemistry, Technology for Sustainable Environment, computing technology, pollution prevention, Engineering, Environmental Engineering, pollution prevention design tool, clean technologies, cleaner production, industrial wastewater, data sharing, polymer waste disposal, clean technology, modeling, pollution control, metal casting, computer science, pollution prevention design, environmental simulation and design tools, environmental data, computer simulation modeling, polymers, pollution prevention model, clean manufacturing designs

Progress and Final Reports:

  • 1997
  • Final

  • Main Center Abstract and Reports:

    R825370    EERC - National Center for Clean Industrial and Treatment Technologies (CenCITT)

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
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    R825370C046 Clean Process Advisory System (CPAS) Core Activities
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    R825370C054 Predictive Tool for Ultrafiltration Performance
    R825370C055 Heuristic Reactor Design for Clean Synthesis and Processing - Separative Reactors
    R825370C056 Characterization of Selective Solid Acid Catalysts Towards the Rational Design of Catalytic Reactions
    R825370C057 Environmentally Conscious Manufacturing: Prediction of Processing Waste Streams for Discrete Products
    R825370C064 The Physical Properties Management System (PPMS™): A P2 Engineering Aid to Support Process Design and Analysis
    R825370C065 Development and Testing of Pollution Prevention Design Aids for Process Analysis and Decision Making
    R825370C066 Design Tools for Chemical Process Safety: Accident Probability
    R825370C067 Environmentally Conscious Manufacturing: Design for Disassembly (DFD) in De-Manufacturing of Products
    R825370C068 An Economic Comparison of Wet and Dry Machining
    R825370C069 In-Line Copper Recovery Technology
    R825370C070 Selective Catalytic Hydrogenation of Lactic Acid
    R825370C071 Biosynthesis of Polyhydroxyalkanoate Polymers from Industrial Wastewater
    R825370C072 Tin Zeolites for Partial Oxidation Catalysis
    R825370C073 Development of a High Performance Photocatalytic Reactor System for the Production of Methanol from Methane in the Gas Phase
    R825370C074 Recovery of Waste Polymer Generated by Lost Foam Technology in the Metal Casting Industry
    R825370C075 Industrial Implementation of the P2 Framework
    R825370C076 Establishing Automated Linkages Between Existing P2-Related Software Design Tools
    R825370C077 Integrated Applications of the Clean Process Advisory System to P2-Conscious Process Analysis and Improvement
    R825370C078 Development of Environmental Indices for Green Chemical Production and Use