MEMORANDUM

TO:  Portland Cement Docket

SUBJECT:  Site visit to the Lafarge cement plant in Alpena. Michigan.  

FROM:  Keith Barnett, USEPA/OAQPS/SPPD/MMG

DATE:  October 4, 2006

	On September 26 and 27, 2006, representative of the EPA met with
representative of Lafarge North America at the Lafarge cement plant in
Alpena, Michigan.  The main purpose of the visit was for the EPA Office
of Research and Development to obtain information to develop a life
cycle analysis of mercury at a facility that used utility boiler fly ash
as a cement kiln feed.

The attendees were as follows:

Lafarge North America:

Brian Gasiorowski

Craig M. Ryan

Dave Diedrick

Robert Budnik

Gil Peterson 

J.R. Keen 

U. S. Environmental Agency:

	Keith Barnett, OAR/OAQPS/SPPD/MMG

	Susan Thorneloe, ORD/NRMRL/APPCD

	

Michigan Department of Environmental Quality

	

	Mark Stephens (September 26, only)

On September 26 the Lafarge representatives gave a tour of the facility.
 On September 27 we discussed various issue related to the use of fly
ash as a cement kiln feed specific to the Alpena facility.  Some key
points were:

The facility was under regulatory pressure to address total hydrocarbon
and sulfur dioxide problems that resulted from materials present in the
Paxton quarry shale.

Switching to fly ash also reduced the alkali content of the raw mix to
allow production of low alkali cement.  The facility now produces Type 2
low alkali cement.  Previously it produced Type 1 cement.

Lafarge still has a cost associated with the fly ash, but the cost is
subsidized by the utility who supplies the fly ash.

Lafarge noted a 10 percent kiln efficiency improvement when they
switched to fly ash from shale.

The mercury content of the limestone is fairly constant.  The cement
kiln dust has some variability, and the plant has not bracketed that
variability as yet.  Most variability is in the coal, coke, and fly ash.
 The fly ash mercury content ranges from 0.4 to 0.6 ppm.  

They are trying to develop a more consistent sampling methodology.  They
have shifted away from sampling the individual feed materials to
sampling the raw meal.

Fuels are part of the raw meal chemistry.  Fuels provide oxides and
alumina to the process.  They try to buy one fuel blend and stick with
it.

The data on materials use would give an idea of the shale displacement
amount (i.e. how many tons of fly ask to replace one ton of shale).   

Lafarge presented some data on annual emissions and materials use.  They
did not provide a copy of these data during the site visit, but agreed
to provide them at a later date.  A copy of the other presentation
materials is attached.

 

