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A new Energy Saving method of manufacturing ceramic products from waste glass

05 Jul 2002-

AbstractThis final report summarizes the activities of the DOE Inventions and Innovations sponsored project, ''A New Energy Saving Method of Manufacturing Ceramic Products from Waste Glass.'' The project involved an innovative method of lowering energy costs of manufacturing ceramic products by substituting traditional raw materials with waste glass. The processing method is based on sintering of glass powder at {approx}750 C to produce products which traditionally require firing temperatures of >1200 C, or glass-melting temperatures >1500 C. The key to the new method is the elimination of previous processing problems, which have greatly limited the use of recycled glass as a ceramic raw material. The technology is aligned with the DOE-OIT Glass Industry Vision and Roadmap, and offers significant energy savings and environmental benefits compared to current technologies. A U.S. patent (No. 6,340,650) covering the technology was issued on January 22, 2002. An international PCT Patent Application is pending with designations made for all PCT regions and countries. The goal of the project was to provide the basis for the design and construction of an energy-efficient manufacturing plant that can convert large volumes of waste glass into high-quality ceramic tile. The main objectives of the project were to complete process development and optimization; construct and test prototype samples; and conduct market analysis and commercialization planning. Two types of ceramic tile products were targeted by the project. The first type was developed during the first year (Phase I) to have a glazed-like finish for applications where slip resistance is not critical, such as wall tile. The processing method optimized in Phase I produces a glossy surface with a translucent appearance, without the extra glazing steps required in traditional tile manufacturing. The second type of product was developed during the second year (Phase II). This product was designed to have an unglazed appearance for applications requiring slip resistance, such as floor tile. The coarser matte finish of this product type was produced by modifying the basic process to include crystalline fillers and partial crystallization of the glass. Additional details of the project results are discussed in Section III.

Topics: Glass recycling (58%), Tile (56%), Glazing (51%), Ceramic (50%)

Summary (2 min read)

I. SUMMARY OF ORIGINAL PROJECT GOALS

  • This final report summarizes the activities of the DOE Inventions and Innovations sponsored project, "A New Energy Saving Method of Manufacturing Ceramic Products from Waste Glass.".
  • The project involved an innovative method of lowering energy costs of manufacturing ceramic products by substituting traditional raw materials with waste glass.
  • The main objectives of the project were to complete process development and optimization; construct and test prototype samples; and conduct market analysis and commercialization planning.
  • The processing method optimized in Phase I produces a glossy surface with a translucent appearance, without the extra glazing steps required in traditional tile manufacturing.
  • The second type of product was developed during the second year (Phase II).

III. DISCUSSION OF PROJECT RESULTS

  • The project was divided into 15 tasks as listed in the Milestone Table on p.18.
  • Three glass particle size ranges were prepared from crushed clear glass containers, and subjected to three moisture levels to produce nine variations.
  • These results confirm the adverse affects of water, and demonstrate the need for dry processing below a specific particle size range.
  • Measurement of the green strength and density was used to evaluate the binder system and pressing variables.
  • C. Phase I Prototype Fabrication and ANSI Testing (Tasks 5 and 6) The required sample sizes and quantities for the ANSI testing, based on the Tile Council of America requirements and the most recent versions of the ASTM test procedures, were first determined.

Coefficient of

  • *Type A tiles were made from recycled mixed-color container glass.
  • In some cases fillers which dissolved into the glass still produced roughened surfaces, even without crystallization of the glass.
  • This procedure was modified in the recent testing to more quantitatively compare variations in thermal shock resistance.
  • The results of the Phase II development work provided additional understanding on methods for controlling the surface finish, texture, and color.
  • Small amounts of other types of fillers were used to produce matte tile surfaces with improved properties for floor tile applications.

Test

  • The tiles with mattes surfaces had significantly enhanced slip resistance with dry values greater than 0.8, and wet values greater than 0.6.
  • One additional test was also conducted by the Tile Council of America, Thermal Shock Resistance (ASTM C484).
  • Additional ceramic tile market data was collected, along with information on the construction and manufacturing costs of ceramic tile production.
  • These data were used to further develop a detailed commercialization plan for the technology with initial timing and cost estimates.
  • A local glass manufacturing company and three recycled-glass processors were also visited during the trip.

IV. MILESTONE TABLE

  • The reduced costs for Phases I and II were balanced by additional spending on Task 14 (Market Analysis and Commercialization Planning).
  • Note 4 - Manufacturing plant design and cost analysis was started in April 2001, earlier than originally scheduled.
  • Note 5 - Market analysis and commercialization planning activities were expanded as discussed above in Notes 1 and 3.
  • Additional details are provided in Sections II and III.

V. ENERGY, ENVIRONMENTAL, AND ECONOMIC SAVINGS

  • The project technology was used to design a manufacturing process for producing ceramic tiles, as discussed in Section III.I. Economic savings result from reduced fuel usage, and replacement of traditional raw materials with waste glass.
  • The cost of waste glass varies significantly from no cost (or even negative cost) to as much as $100/ton, depending on the type of waste glass and region of the country.
  • The data on savings per installed unit presented in this section are used in the next section to calculate the total savings based on market estimates.

VI. MARKET ESTIMATES / TECHNICAL TRANSFER ACTIVITIES

  • Estimates of market penetration for the new technology are provided in row B of Table V. Five years after completion of the project (in 2007) 35 installed units of the new technology are estimated.
  • These savings are listed in rows D-G of Table V, along with the savings for earlier years.
  • A demonstration plant producing 500,000 square feet of tile per year using 1000 tons of recycled glass was designed, as previously discussed in Section III.I. Initial discussions with selected companies have been conducted.

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Approved Final Technical Report
DOE/I&I/10520-5
A New Energy Saving Method of Manufacturing
Ceramic Products from Waste Glass
Final Report
for the Period March 2000 - July 2002
Michael J. Haun
HAUN LABS
122 Calistoga Rd., #116
Santa Rosa, CA 95409
Tel: 707-538-0584
Email: mjhaun@haunlabs.com
Date Published - July 2002
PREPARED FOR THE UNITED STATES
DEPARTMENT OF ENERGY
Under Grant No. DE-FG36-00GO10520

2
TABLE OF CONTENTS
Page
I. SUMMARY OF ORIGINAL PROJECT GOALS .................................................. 3
II. VARIANCE FROM PROJECT GOALS................................................................ 4
III. DISCUSSION OF PROJECT RESULTS.............................................................. 4
A. Phase I Development and Glass Characterization (Tasks 1 and 2)................. 4
B. Evaluation of Commercial Cullet Sources (Tasks 3 and 4)............................. 6
C. Phase I Prototype Fabrication and ANSI Testing (Tasks 5 and 6).................. 7
D. Phase I Demonstration Prototypes and Data Sheets (Task 7) ......................... 9
E. Phase II Process Development and Characterization (Tasks 8 and 9) ............ 9
F. Phase II Prototype Fabrication (Task 10).......................................................... 12
G. Phase II Prototype ANSI Testing (Task 11)..................................................... 12
H. Phase II Demonstration Samples and Data Sheets (Task 12).......................... 14
I. Manufacturing Plant Design / Cost Analysis (Task 13).................................... 14
J. Market Analysis and Commercialization Planning (Task 14).......................... 15
K. Project Management and Reporting (Task 15)................................................. 16
IV. MILESTONE TABLE............................................................................................ 17
V. ENERGY, ENVIRONMENTAL, AND ECONOMIC SAVINGS....................... 19
VI. MARKET ESTIMATES / TECHNICAL TRANSFER ACTIVITIES ............... 21

3
I. SUMMARY OF ORIGINAL PROJECT GOALS
This final report summarizes the activities of the DOE Inventions and Innovations
sponsored project, "A New Energy Saving Method of Manufacturing Ceramic Products
from Waste Glass." The project involved an innovative method of lowering energy costs
of manufacturing ceramic products by substituting traditional raw materials with waste
glass. The processing method is based on sintering of glass powder at ~750ºC to produce
products which traditionally require firing temperatures of >1200ºC, or glass-melting
temperatures >1500ºC.
The key to the new method is the elimination of previous processing problems,
which have greatly limited the use of recycled glass as a ceramic raw material. The
technology is aligned with the DOE-OIT Glass Industry Vision and Roadmap, and offers
significant energy savings and environmental benefits compared to current technologies.
A U.S. patent (# 6,340,650) covering the technology was issued on January 22, 2002. An
international PCT Patent Application is pending with designations made for all PCT
regions and countries.
The goal of the project was to provide the basis for the design and construction of
an energy-efficient manufacturing plant that can convert large volumes of waste glass
into high-quality ceramic tile. The main objectives of the project were to complete
process development and optimization; construct and test prototype samples; and conduct
market analysis and commercialization planning.
Two types of ceramic tile products were targeted by the project. The first type
was developed during the first year (Phase I) to have a glazed-like finish for applications
where slip resistance is not critical, such as wall tile. The processing method optimized
in Phase I produces a glossy surface with a translucent appearance, without the extra
glazing steps required in traditional tile manufacturing. The second type of product was
developed during the second year (Phase II). This product was designed to have an
unglazed appearance for applications requiring slip resistance, such as floor tile. The
coarser matte finish of this product type was produced by modifying the basic process to
include crystalline fillers and partial crystallization of the glass. Additional details of the
project results are discussed in Section III.

4
II. VARIANCE FROM PROJECT GOALS
Overall the project goals were completed as planned and on schedule. The only
major variance occurred during the second year. The success of the ANSI test results at
the end of the first year allowed additional marketing and commercialization planning to
be conducted in place of most of the Phase II characterization work. This also allowed
the manufacturing plant design and cost analysis work to begin earlier than originally
planned.
III. DISCUSSION OF PROJECT RESULTS
The project was divided into 15 tasks as listed in the Milestone Table on p.18.
The project results are summarized in the following sections for each of these tasks.
A. Phase I Development and Glass Characterization (Tasks 1 and 2)
The Phase I research focused on optimizing the process variables. A series of
interrelated experimental studies investigated the effects of glass composition,
contaminants, glass powder particle size, binder system, pressing pressure, and firing
conditions on the densification behavior of tile samples. The results of these studies are
summarized in the following paragraphs.
The effect of moisture (considered a contaminant to the process) on the
densification behavior as a function of glass particle size was investigated. Three glass
particle size ranges were prepared from crushed clear glass containers, and subjected to
three moisture levels to produce nine variations. The results provide important data on
how finely the glass can be crushed and ground before drying is necessary. When coarse
glass particles (>30 mesh) were exposed to water, and then subsequently dried and
processed, the densification behavior was not affected. This result indicates that
commercial cullet will be an acceptable raw material, even if it has been exposed to
water.
When finer particles (<30 mesh) were exposed to water, the densification
behavior was adversely affected. However, this greatly depended on the type of moisture
exposure, and can be correlated to the concentration and pH of the water present, and also
to the type of binder and method of binder addition. These results confirm the adverse
affects of water, and demonstrate the need for dry processing below a specific particle

5
size range. The results of this study were used to establish a standard drying, crushing,
and grinding procedure for the remaining studies.
The effect of glass powder particle size on the pressing and firing processes was
investigated for three particle size ranges with a fixed binder system. As the particle size
was decreased the quality of both pressed and fired samples improved. This study
provided data on the range of firing conditions (heating rate, maximum temperature, and
hold time) that will be required. These results indicate that a very rapid firing process
will be possible with a maximum temperature of <800°C and hold time of only five
minutes.
The effect of inorganic contaminants on the densification behavior of fine glass
powder was investigated. Five contaminants were added in three amounts to produce
fifteen combinations. The densification behavior was not significantly affected with one
weight percent additions. With higher contaminant levels of five and twenty percent, the
densification was affected, but this greatly depended on the type of contaminant. These
results indicate that small amounts of inorganic contaminants, when finely ground, will
not significantly affect the densification behavior. However, the color and surface texture
of the samples were affected, at least slightly, for all variations studied.
Studies were conducted to optimize the binder system and pressing conditions.
Measurement of the green strength and density was used to evaluate the binder system
and pressing variables. A diametral compression test fixture was setup to measure the
tensile green strength of pressed cylindrical samples. Measurements with this fixture
agree well with literature results.
The green strength and density were measured as a function of variations in
binder type, percentage, and molecular weight, and also pressing pressure and hold time.
The green density and strength increased with increasing pressing pressure, and depended
greatly on the binder system. The hold time during the pressing process was found to
have only a small effect on the green density and strength. This result indicates that a
rapid pressing operation with a short hold time is possible. Based on these results a
binder system was selected to fabricate the Phase I prototype tile samples.
Particle size, surface area, and differential thermal analysis (DTA) were measured
on glass powders by Corning Laboratory Services (Corning, NY), and x-ray diffraction
(XRD) and x-ray fluorescence (XRF) by the Mineral Lab (Lakewood, CO). The DTA
results clearly show the glass transition region, and correlate well with the firing studies.
These data are important for characterizing the glass powders of the current study, and
for comparison with future glass powders. XRD and XRF were conducted on additional

Citations
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28 Mar 2011
Abstract: A Thesis submitted to the Department of Mechanical Engineering for the Degree of Master of Engineering in Energy Technology