'YBANEZ Hector"

< HECTOR.YBAN EZ@essroc

.com>

0711912007 04:40 PM

To .Keith BarnetURTP/USEPA/US@EPA

cc

bcc

Subject

I agree that a conference call would be good.

Does Friday at l1:00 suit your schedule?

In answer to your first question about "CKD Removed" and "CKD Returned", there are differences at each

plant that need to be explained. When we have the rest of the mercury data Essroc will provide you with

mass balance calculations that will make clear the amounts and concentrations of mercury entering and

leaving the kilns.

I'm sure that you can appreciate that Essroc moved quickly to begin sampling.

Names selected are in some cases not as clear as we would like, but sample bottles were sent and chain of

custody worksheets prepared using the names initially selected. We have reached a point where changing

some sample names is appropriate to clarify for the ùgency what these samples represent.

Thank you for raising these issues now, so that we can make these changes to limit confusion in the future.

I have provided a brief description for each of the plants that you mentioned.

Bessemer - Both kilns control particulate matter (PM) using electrostatic precipitators (ESPs). Dust from

the first and sometimes the second field is conveyed to a bin for temporary storage. This is CKD Returned.

At Bessemer, CKI) returned contains the larger size fraction. At Bessemer CKD retumed is blown directly

into the burning zone like coal dust. This is called insufflation and is a requirement of the Bessemer air

permit to control nitrogen oxide emissions. Kilns that insufflate CKD may be a separate category for

MACT purposes. The CKD removed at Bessemer comes from the last fields of the EPS. This represents

the smallest dust fraction. The CKD retumed is not a raw material component. The amount of dust

recirculating from insufflation to recapture in the first fields of the ESP is difñcult to determine.

There is no system to directly measure the insufflated dust so estimates of returned dust must be made

indirectly. The mercury In CKD returned has already been counted in the mass balance as mercury fed

into the kiln with slurry. Double counting the mercury In CKD returned would result in a mass balance

error.

Logansport - PM emissions are currently controlled using an ESP at Logansport but a fabric filter is under

construction. CKD removed comes from the last fields of the ESP, as it does at Bessemer.

The CKD returned from the first fields is fed directly into the kilns using a vortex feeder separate from the

slurry. As at Bessemer, it is difñcult to measure the CKD returned. The mercury has already been counted

through analysis of the slurry feed. Recirculating mercury in CKD returned to the kiln is not a feed

component.

Nazareth - No CKD is removed from the kiln at the Nazareth plant. In fact, it is unclear that there is any

material that can properly be called CKD that is generated at Nazareth. Raw materials ground in the

Loesche (raw) mill are conveyed using hot stack gases to dry the feed. The feed from the raw mill adsorbs

mercury from the stack gases. The raw mill discharge is blown pneumatically into the homogenizing silo

bins where it is mixed with other materials.

The other materials include the dust collected in the baghouse controlling PM emissions from the Loesche
mill. This material is collected in hoppers under the baghouse and conveyed by screw conveyors and

enclosed elevators into the homogenizing silo. A second baghouse controls PM emissions from a kiln

exhaust stream that does not pass through the Loesche mill. Dust collected in this fabric filter is also

conveyed to the homogenizing silo using screw conveyors and elevators. The material from the

homogenizing silo, containirg all of the materials described above is called kiln feed and entrees the kiln

near the top of The preheater tower. Mercury from stack gases condenses onto the smallest particles in the

kiln feed recirculating and accumulatngnthe dust from the two baghouses as well as the raw mill

discharge. There is a significant increase in mercury emissions when the Loesche mill is taken out of

service. This typically occurs for about 8 hours every ten days to perfbrm maintenance on the mill. There

is no regular schedule of mill outages. The material collected in the fabric filters goes directly to the

homogenizing silo. There is no way to measure the amount of this material recirculating within the system.

As in the case of Bessemer and Logansport, the baghouse dusts are not raw material components.

Counting the mercury recirculating in this fabric filter dusts would be double counting the mercury.

Essroc will change the name from CKD returned to Baghouse dust to limit conftsion on this point. A

separate tab for baghouse dust returned as feed will be created to clarify that this material should not be

named "CKD returned".

San Juan - The kiln system at San Juan is similar to Nazareth with no CKD removed from the Kiln and

fabric filter dust returned to the homogenizng silo where it is mixed with the material discharged from the

Loesche (raw) mill The raw mill adsorbs mercury from stack Gases and includes recirculating mercury.

The baghouse dust also contains adsorbed mercury.

These are not raw material components and including them as raw materials would double count Mercury

entering the kiln. As in the example of Nazareth, "raw mill discharge" is a more Appropriate term than raw

mill feed. The two components entering the raw mill are limestone And mill scale. We will remove raw

mill discharge from the raw material component (RMC) tab.

The data is duplicated in the tab named "In Ln RM Feed" and should better be named "In Ln RM Dischg".

These changes will be made and an improved worksheet sent on Thursday in Preparation for the conference

call on Friday.

Speed - Speed is similar to Nazareth and San Juan, except that some CKD is removed from kiln I and a

single Loesche mill is used to prepare kiln feed for both kiln I and kiln 2. The dust collected in the kiln I

baghouse is transferred to a temporary storage bin. This dust is used to manufacture masoffy cements.

Some of this dust is sold directly to customers. Any kiln I fabric filter dust that is not used to make

masonry cement or sold directly is returned to kiln I in a system separate from the kiln I Loesche mill feed

system. The CKD removed (sold directly or as masonry cements) is the same as CKD returned at Speed.

The amount of CKD removed or sold is accurately known because these materials are weighed. However,

the recirculating CKD returned is not measured and is not a raw material component. Including the

mercury from CKD returned would result in a mass balance error because the mercury in this material has

already been counted in the feed components. Changes to the Speed raw mill discharge and RMC

information that duplicate these data will be made to clarifi' the mass balance calculations.

In short, materials collected in the fabric filters and ESPs are returned to the kilns in Different Ways

including insufflation, vortex feeders, mixing in a homogenizing silo and a separate kiln feed stream. When

CKD is retumed it is not a raw material component and Treating it as a raw material would result in

double counting of mercury in recirculating Materials. It is not part of the slurry at Bessemer or

Logansport and it is not parl of the Raw mill discharge at Nazareth, San Juan or Speed. It is returned as

described above.
We agree that raw mill feed should not be equated with raw mill discharge. To clarify this Poing we will

create a tab for raw mill discharge and delete the duplicated data from the Raw material components tab.

At Nazareth what is fed to the kiln is a combination of raw mill discharge that has absorbed mercury from

stack gases plus dust from two fabric filters that have collected dust that has also adsorbed mercury from

stack gases and recirculated this mercury increasing the mercury concentration in the recirculating

materials. The raw material components are analyzedindividually including limestone, flyash, bottom ash,

alumina, iron, clay, and CKD landfilled and subsequently reclaimed as a raw material. For wet kilns with

indirect raw mills it is possible To analyze the slurry in addition to the raw material components to compare

the Mercury in each component with the mercury in the kiln feed. In the case of preheater kilns, where

mercury in stack gases is adsorbed onto feed materials in the Loesche mill and the dust collected in the ESP

or fabric filter, much of the mercury recirculates within the kiln and Must not be double counted as

mercury entering the kiln with feed.

I hope that this clarifies the mercury mass balance issues for these preliminary data.

As I said, Essroc will provide you with a complete mass balance estimate for mercury for each Of our kilns

when we are prepared to provide the rest of the mercury analyses.

Hector

Essroc Cement Corp.

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Essroc Cement Corp.
-Keith

BarnettlRTP/USEPAlUS

07/17/200702:54 PM

Dear Hector:

To "YBANEZ Hector" <HECTOR.YBANEZ@essroc.com>

cc "Michael Laney" <mnl@rtLorg>, green@rtLorg

bcc

Subject Questions on the ESSROC Data submittal

We have some additional question on your data submittal. Once you have had time to look over the

questions, why don't we set up a call, just in case more questions come up from your answers.

-You report Hg content of "CKD removed" and "CKD returned." I assume

CKD returned is what is put back into kiln. How is it retuned? It is not

reported as a "raw material component" for any of the kilns that return it

(Bessemer,

Logansport, Nazareth, San Juan, Speed). So is it part of the slurry at

Bessemer and Logansport? And for the dry kilns, is the CKD part of the

"raw mill discharge" at Nazareth and Speed? Or is it returned by another

method?

-In the "Inline raw mill feed" table, the reported Hg.for Nazareth and

Speed is the same as "Raw Mill Discharge" in the 2 tables of "Raw

Material Components" for Nazareth and Speed. This is a little confusing

to me because I would not have equated raw mill feed with raw mill

discharge.

-In the "Raw Material Components" tables for Nazareth and Speed, what is

being fed to the kilns: raw mill discharge only, or raw mill discharge,

limestone, clay, iron, etc.

- Similar to the previous question, the Hg content of slurry in the "Raw

Material Components" tables for Bessemer, Logansport, and Martinsburg is

the same as that in the "indirect mill feed" table. What is the total Hg

going into the wet kilns - the Hg in the slurry only or the Hg reported

for the slurry, limestone, mill scale, etc.?

Keith W. Barnett

USEPAlOAQPS/SPPD/MMG

Mail Code 0243-02

Research Triangle Park, NC 27711

919-541-5605

barnett.keith@epa.gov