2004 Progress Report: Utilization of Paper Mill Waste in Ceramic Products

EPA Grant Number: R830420C002
Subproject: this is subproject number 002 , 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: Utilization of Paper Mill Waste in Ceramic Products
Investigators: Earl, David A. , Sinton, Chris
Institution: Alfred University
EPA Project Officer: Klieforth, Barbara I
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 (2002) Recipients Lists
Research Category: Targeted Research , Congressionally Mandated Center

Objective:

This is one of the subprojects conducted by the Center for Environmental and Energy Research (CEER).  The main objectives of this research project are to:  (1) characterize paper waste material from at least three sources; (2) study the performance of ceramic tile body formulations containing variable amounts of waste materials; and (3) estimate the environmental and economic impacts of using waste materials.  Ceramic tile products, with formulations incorporating boiler fly and bottom ash, were studied to evaluate and quantify composition-processing-properties relationships.  Tile manufacture is used in this investigation because:  (1) the ash is most readily compatible with the starting materials; (2) production volumes are high; (3) there are multiple manufacturing locations across the U. S.; and (4) the raw materials specifications are relatively broad.

Progress Summary:

We have characterized bottom ash and fly ash samples from International Paper Co. in Ticonderoga, New York.  Samples were received in monthly intervals over 4 months (October 2002-January 2003).  In addition, one sample of recaust grit was received in December 2002.  The International Paper Androscoggin Mill also sent one sample of bottom ash in November 2002.

The ash was received in 5 gallon pails, containing 40-50 lbs of bottom ash or 20-30 lbs of fly ash.  The bottom ash has an initial particle size that is much too large to be used directly as a batch material for ceramic processing, therefore, it was ball milled to obtain the appropriate size (D50 = 10-15 μm).  The ash composition was found to have significant variations in SiO2, Al2O3, and CaO over the time period observed (October 2002-January 2003).  These are three important oxides with respect to ceramic (porcelain) compositions.  The Androscoggin bottom ash has a composition that is significantly different from the Ticonderoga ash, with higher Al2O3 and lower SiO2.  These variations over time and between sites could lead to some complications in optimizing ceramic body formulations on an industrial scale, unless the ash is blended to a constant composition before shipment or the ceramic formulation is modified each time the ash composition changes.  The composition within single samples, however, has been uniform.  The November 2002 bottom ash sample from Ticonderoga has a composition close to the average for the samples collected over 4 months, and, thus, has been selected for subsequent experiments with porcelain body formulations.  All of the ash samples were also examined using qualitative X-ray diffraction (XRD) to identify crystalline phases.  The major phases were quartz (SiO2) and calcite (CaCO3), which are commonly present in raw materials for ceramic products.

The sintering/melting behavior of the ash materials has been characterized using a hot-stage microscope, and the results were compared to typical porcelain batch materials.  The results show the ash melts at lower temperatures than traditional fluxes (nepheline syenite and feldspar) for manufacturing ceramic products.  The stronger fluxing action may provide some benefits, such as lower-temperature firing cycles.  Chemical analysis results show the paper mill ash has higher amounts of fluxing oxides than traditional raw materials.  Also, the carbon content is much higher for the mill ash, which may cause problems with glaze bubbling, but only if volatilization continues above the glaze melting temperature.  Because the ash materials have lower SiO2 and Al2O3 levels than traditional raw materials, incorporation into ceramic formulations will require systematic adjustments of the other batch materials to achieve the target oxide composition.

Experimental body compositions that incorporate paper mill ash have been calculated and batched.  The initial target composition is based on industrial porcelain.  Compositions were calculated by replacing A-400 nepheline syenite flux with the ash material, based on the chemical analysis data.  The target batch formula was converted to mol percent oxides and the molar levels of R2O + RO fluxes were matched with the necessary amount of ash.  Next, the other raw materials were adjusted to keep the SiO2 and Al2O3 levels close to the typical porcelain body composition.  Using this method, an “ideal” batch containing bottom ash was calculated, as well as two other formulations with bottom ash (one with higher ash and one with lower ash; Table 1).

Table 1.  Calculated Compositions for Experimental Formulas

Raw Material

Weight % Compositions

Porcelain

5% Ash

“Ideal”

8% Ash

Tile Kaolin #6

29

35.5

34.3

33.5

Todd Light Ball Clay

6

15.5

15

14.5

A-400 Nepheline Syenite

21

-

-

-

Alcan C-71 Alumina

10

10

10

10

Silcosil 63 Silica

34

34

34

34

Ash

-

5

6.7

8

The control porcelain composition and the “ideal” ash composition have been batched, prepared into a slurry, filter pressed, and extruded into rods to be fired and tested.  The other two ash compositions will be extruded after some additional testing is done to optimize the slurry suspensions.  The surface chemistry of the ash (zeta potential vs. pH) must be determined to optimize the slurry suspension stability and solids loading, but there have been problems with the equipment that have delayed testing.  The thermal behavior of the ash must be tested, but the equipment (DSC-TGA) has not been working properly.  There also have been delays in obtaining raw materials for batching the bodies and obtaining parts for the extruder.  Problems were encountered in the processing of the rods (cracking/bending upon drying), but these have been resolved.

The project is now focusing on substituting bottom ash (November 2002) from the Ticonderoga mill into porcelain at different levels.  A particular porcelain composition was chosen for the work, because, recently, another project at Alfred University investigated the substitution of waste glass into this formula.  The bottom ash most closely resembles traditional raw materials that currently are used and is most easily substituted into the batch.  After trials with bottom ash have been completed, fly ash will be substituted and studied.

It was originally planned that the use of dregs and grit from the recausticization process would be investigated.  This is no longer possible as a result of a change in the process at the paper mill, resulting in much lower production of these two waste streams (only one sample of recaust grit has been received).  Initially, the work plan included an investigation of wastes from four different paper mills.  Samples have only been received from International Paper Co. in Ticonderoga, New York, and Androscoggin, Maine.  Only one sample was received from the Androscoggin mill.  Therefore, the study is focusing on the ash (bottom ash and fly ash) from the Ticonderoga mill.

Future Activities:

December 2003–January 2004

We will investigate the surface chemistry of the ash (zeta-potential vs. pH) and the suspension behavior (viscosity vs. shear rate) of formulas containing different levels of the ash.  We will determine the firing behavior of the ash using DSC-TGA methods.  The results will better define the processing behavior.

January 2004–February 2004

The other two ash compositions will be batched, filter pressed, and extruded.  All of the compositions will be fired using an industrial firing cycle.  We will perform pyroplastic deformation testing on all compositions using a method developed at Alfred University.

February 2004–May 2004

We will measure and compare physical properties of the fired samples.  We will determine relationships between ash content, type, and composition and the physical properties.  Measurements will include thermal expansion coefficient (dilatometry), fired color (spectrophotometry), mechanical strength (modulus of rupture), and fired density/porosity (water absorption).  We will characterize the fired microstructures using scanning electron microscopy (SEM) and quantitative XRD.  We will determine any significant differences in phases between the formulas and their effect on properties.

Finally, we will consider the economic feasibility of using the ash for industrial production of ceramic products.

Journal Articles:

No journal articles submitted with this report: View all 1 publications for this subproject

Supplemental Keywords:

fly ash, bottom ash, paper mill waste, characterization, porcelain, surface chemistry, physical properties, thermal expansion, dilatometry, spectrophotometry, modulus of rupture, density, apparent porosity, technology for sustainable environment, glass technology, sustainable industry/business,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, TREATMENT/CONTROL, Sustainable Industry/Business, POLLUTION PREVENTION, Sustainable Environment, Energy, Technology, Technology for Sustainable Environment, Environmental Engineering, energy conservation, clean energy, cleaner production, sustainable development, clean technologies, environmental conscious construction, boron rich carbon, clean manufacturing, energy efficiency, energy technology, alternative fuel, alternative energy source

Relevant Websites:

http://ceer.alfred.edu/ Exit
http://ceer.alfred.edu/research/paperwaste.html Exit

Progress and Final Reports:

Original Abstract
  • Final Report

  • Main 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).
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