Grantee Research Project Results
2004 Progress Report: Material and Environmental Sustainability in Ceramic Processing
EPA Grant Number: R830420C005Subproject: this is subproject number 005 , established and managed by the Center Director under grant R830420
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Center for Environmental and Energy Research (CEER)
Center Director: Earl, David A.
Title: Material and Environmental Sustainability in Ceramic Processing
Investigators: Schwerzler, Gretchen I. , Earl, David A. , Carty, William
Institution: Alfred University
EPA Project Officer:
Project Period: September 1, 2003 through August 31, 2005
Project Period Covered by this Report: September 1, 2003 through August 31, 2004
RFA: Targeted Research Center (2004) Recipients Lists
Research Category: Targeted Research , Hazardous Waste/Remediation
Objective:
Whitewares manufacturing currently produces more than 100 million pieces of dinnerware and other products each year. Because of inefficient use of water and raw materials, large amounts of waste are generated. The waste generated solely by Buffalo China in the glazing process totals over 500,000 pounds of hazardous and non-hazardous solids and over 10 million cubic feet of water per year. Reduction of the amount of hazardous waste through use of hydrocyclone separation of particles in combination with the development of glazes using recycled materials will decrease the use of capital, energy, and natural resources.
Currently no recycling of raw materials is practiced in the whitewares industry. Glaze waste is usually a combination of multiple production colored glazes often containing lead, cadmium, and chromium pigments that in combination produces a dark, non-marketable color and must be stored, treated, and disposed of as hazardous waste. Separating the waste by particle size isolates different pigments that could then be reintroduced into the production colors as a percentage of the glaze. Prior work by Ross Newcomb at Alfred University showed that color difference between the waste and production glazes was the main problem with large additions of waste to production. Finer separation of the waste particles as well as adjustments to current production glazes could eliminate these problems.
Initial trials at Alfred University analyzed the waste samples and determined the relationship between particle size, density, and sedimentation velocity of the particles using Stokes’ Law. Trials showed that separated waste containing frit and colorants could be reused in production glazes as batch additions. Using gravity sedimentation for large particles and repeated cycling through a small hydrocyclone (2.54 cm) for small particles, three components were separated by particle size: (1) frit, clays, and zircon opacifier (< 5 µm); (2) frit and light colorants (5-20 µm); and (3) frit and Cd-Se red and V yellow colorants (> 20 µm). The process demonstrated the reuse of waste materials in production glaze but was inefficient and not suited to industry. A CEER seed project enabled collaboration with Krebs Engineers in Tucson, Arizona, who developed an industrial system for separation based on the known separation points for the waste, solids densities, the feed slurry volume, weight percent solids, pH, and temperature. The objective of this project is to determine the operating parameters of the separation system, the efficiency of material recovery, and the feasibility of implementing this separation technology into an industrial process.
Progress Summary:
The proposed industrial system was scaled down in size from six interconnected cyclones of two different sizes per unit to only two cyclones and constructed with consultation from Krebs Engineers and Buffalo China. Several six-cyclone units would be needed to handle industrial quantities of material. The procedures for a simulation of the continuous industrial process were established based on suggested operating parameters from Krebs Engineers. The ability to separate different particles based on size using the system was confirmed using a test with two Alumina powders, A10-325 Mesh and A16 SG, with different particle size distributions.
Several large batches of glaze waste were collected from Buffalo China over a 2-month period. Prior work by Newcomb showed little variation in glaze waste composition over time. All batches where then mixed thoroughly and combined for the hydrocyclone trials. A full characterization of three representative samples was performed including particle size distribution, chemical analysis, density, and color value. The mixture was separated into 55 gallon batches for the hydrocyclone trials. Three separate trials using a glaze waste mixture containing multiple pigments from Buffalo China were conducted to determine if particles of various density and overlapping particle size distribution could be separated. The same characterization of the original glaze waste was performed on samples at each separation point for comparison. Despite color variation in the fired glaze at each separation point, and noted shifts in the particle size distribution, the ability to cleanly extract specific particles within a specific size range was not at the target efficiency expected by Krebs Engineers.
To demonstrate the ability of a hydrocyclone to separate particles of equal sedimentation velocity with overlapping particle size distributions and unequal density, a trial using an Alumina powder and a leaded Silica frit was conducted. The results confirmed that particles of equal sedimentation velocity could not be efficiently separated using hydrocyclones. To overcome this limitation of the glaze waste constituents it was proposed that selective agglomeration of specific particles be considered. By determining the surface chemistry of all the glaze constituents, adjustments could be made to the waste material that would cause specific groups of particles to agglomerate, forming a larger particle size with a greater difference in sedimentation velocity from other non-agglomerated particles and making the separation process easier.
The surface chemistry of the leaded silica frit, 12 different stains, and a zircon opacifier were attempted to be determined using standard back titration methods. Data did not reveal a clear isoelectric point (i.e.p.) of the particles. A sedimentation test for estimating the i.e.p. of the leaded silica frit was conducted, and the i.e.p. was determined to be around 2-3 pH.
Future Activities:
Two additional hydrocyclone separation tests are proposed to test the applicability of selective agglomeration and show the difference in separation based on the rheology of the glaze waste system. For the first, the system will be flocculated to create larger frit particles and in the second, the system will be deflocculated. These tests will be compared to help determine if the principle of selective agglomeration based on surface chemistry to create larger particles with a greater difference in sedimentation velocity is viable.
Supplemental Keywords:
hydrocyclone, hazardous waste, recycling, sedimentation velocity, materials, selective agglomeration, surface chemistry, particle size distribution, classification, separation, Stoke’s law,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, TREATMENT/CONTROL, Sustainable Industry/Business, POLLUTION PREVENTION, Environmental Chemistry, Sustainable Environment, Energy, Technology, Technology for Sustainable Environment, Chemistry and Materials Science, Chemicals Management, clean technologies, cleaner production, green design, waste reduction, alternative materials, energy efficiency, recycled glaze materials, ceramic processingRelevant Websites:
Progress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R830420 Center for Environmental and Energy Research (CEER) Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R828737C001 Environmental Impact of Fuel Cell Power Generation Systems
R828737C002 Regional Economic and Material Flows
R828737C003 Visualizing Growth and Sustainability of Water Resources
R828737C004 Vibratory Residual Stress Relief and Modifications in Metals to Conserve Resources and Prevent Pollution
R828737C005 Detecting and Quantifying the Evolution of Hazardous Air Pollutants Produced During High Temperature Manufacturing: A Focus on Batching of Nitrate Containing Glasses
R828737C006 Sulfate and Nitrate Dynamics in the Canacadea Watershed
R828737C007 Variations in Subsurface Denitrifying and Sulfate-Reducing Microbial Populations as a Result of Acid Precipitation
R828737C008 Recycling Glass-Reinforced Thermoset Polymer Composite Materials
R828737C009 Correlating Clay Mineralogy with Performance: Reducing Manufacturing Waste Through Improved Understanding
R830420C001 Accelerated Hydrogen Diffusion Through Glass Microspheres: An Enabling Technology for a Hydrogen Economy
R830420C002 Utilization of Paper Mill Waste in Ceramic Products
R830420C003 Development of Passive Humidity-Control Materials
R830420C004 Microarray System for Contaminated Water Analysis
R830420C005 Material and Environmental Sustainability in Ceramic Processing
R830420C006 Interaction of Sealing Glasses with Metallic Interconnects in Solid Oxide and Polymer Fuel Cells
R830420C007 Preparation of Ceramic Glaze Waste for Recycling using Froth Flotation
R830420C008 Elimination of Lead from Ceramic Glazes by Refractive Index Tailoring
R830420C010 Nanostructured C6B: A Novel Boron Rich Carbon for H2 Storage
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.