Date: October 6, 2008 (Finalized: December 8, 2008)

Subject: Site Visit – American Ma razzi Tile, Inc., Sunnyvale, Texas Clay Ceramics Manufacturing NESHAP EPA Contract No. EP-D-06-118; EPA Work Assignment No. 2-09 RTI Project No. 0210426.002.009

From: Richard Marinshaw

To: Jeff Telander EPA/SPPD/MMG (D243-02) U. S. Environmental Protection Agency Research Triangle Park, N.C. 27711

I. Purpose

The purpose of this visit was to observe the ceramic tile manufacturing process at the American Marazzi Tile, Inc. facility in Sunnyvale , Texas, and to collect information on sources of hazardous air pollutant (HAP) emissions and emission controls in support of the redevelopment of national emi ssion standards for hazardous ai r pollutants (NESHAP) for the clay ceramics manufacturing industry.

II. Place and Date

American Marazzi Tile, Inc. (American Marazzi) 359 Clay Road Sunnyvale, Texas 75182-9710

September 10, 2008

III. Attendees

American Marazzi

Steve Wiederwax, Safety and Environmental Manager Telephone: (972) 226-0110, ext. 22222

Guida, Slavich & Flores

Howard Gilberg, Counsel to American Marazzi Telephone: (214) 692-7121

U. S. Environmental Protection Agency

Jeff Telander Telephone: (919) 541-5427

RTI International

Richard Marinshaw Telephone: (919) 316-3735

IV. Discussion

A. Background

The American Marazzi facility in Sunnyvale , Texas, manufactures ceramic floor tile. The facility consists of two plants: Plant No. 1, which began operating in 1982, and Plant No. 2, which began operations in April 2008. Plan t No. 1 produces red body ceramic and porcelain tiles. Plant No. 2 produces white body porcelain tiles. Plant No. 2 is more automated and when built out will have a higher production throughput rate. Information on the design capacities of the plants is found in Item N o.1 of the Confidential Addendum to the report. Plant personnel pointed out that manufacturer’s design production capacity is based on a certain tile size and weight; when making a different size tile, both the square footage capaci ty and throughput rate will be different than the design capacity for the pl ant. They also noted that Plant No. 2 is not

covered in American Marazzi’s submittal to th e July-August 2008 information collection request for the clay ceramics manufacturing industry.

American Marazzi primarily uses shale, clay, crushed granit e, and sand to produce red body ceramic and porcelain tiles, and uses cl ay, talc, sand, and nepheline syenite to produce white body porcelain tiles. Porcelain tiles are fired at higher temperatures than are ceramic tiles. Another difference between the two types of tiles is that ceramic tiles can absorb up to 5 percent moisture, but the moisture absorption fo r porcelain must be less than 0.5 percent.

Both plants operate 24 hours per day, 7 da ys per week. The facility employs a total of about 300 people in their manufacturing ope rations. Plant personnel noted that about 75 percent of the tile purchased at retail in the U.S. is imported, and foreign competition has been steadily increasing for several years.3

B. Process

The processing steps used at American Marazzi include raw ma terial receiving and processing, body and glaze preparation, tile form ing, drying, glazing, firing, product inspection, and packaging. Attachment 1 is a process descri ption provided by American Marazzi at the time of the visit. The following paragraphs supplemen t the information presented in the attachment.

1. Raw Materials

As noted above, the primary ceramic body materials used by the facility include shale, clays, talc, sand, crushed granite , and nepheline syenite. Refer to the Nonmetallic Mineral Processing section of the attachment for a descri ption of how these ma terials are received, stored, and milled to form a slurry, which is referre d to as “slip.” The slip is then screened and stored until needed for the spray drying step.

2. Body and Glaze Preparation

The slip is pumped to one of three na tural gas-fired spray dryers. The purpose of spray drying is to produce a powder of uniform particle size that can be poured and spread uniformly across tile dies for pressing. Otherw ise, it is difficult to meet the size and quality specifications for larger ceramic tiles. Ameri can Marazzi operates thr ee spray dryers, two in

Plant No. 1 and one in Plant No. 2.

In the spray dryer, the slip is sprayed into a drying chamber. This drying chamber is heated to a temperature of about 450°C (842°F) , for the white body, and 650°C (1202° F) for red body ceramics. Hot air flows countercurrent to th e slip spray and dries the slip, reducing the

moisture content. Data on mois ture content ranges ar e found in Item No. 2 of the Confidential Addendum to the report. Residence time in the spray dryers is less than one minute, and the combination of this short residence time and ope rating temperatures prevents the formation of hydrogen fluoride and hydrogen chloride. After dr ying, the material is di scharged as a fine powder from the bottom of the dryer and conveyed to storage silos for curing. The duration of the curing cycle is provided in Item No. 3 of the Confidential Addendum to the report. Additional information is provided in the Spray Drying section of the attachment.

The facility has a single glaze prepara tion area that serves both plants. The raw materials used to make glazes and glaze pastes incl ude frits, clays, sand, alumina grit, and stains. Many of the stains consist of oxides of metals such as chromium, cadmium, and manganese. These materials are batch-weighe d and transferred to a ball m ill for mixing grinding. The glazes

are then stored until needed. Additi onal information is provided in the Glaze Preparation

section of the attachment.

3. Forming and Drying

In the forming area, the spray-dried pow der is fed into one of several hydraulic presses. Data on maximum tile size produced are found in Item No. 4 of the Confidential Addendum to the report. Plant No. 1 operates se ven press lines, and Plant No. 2 operates three4

press lines. The pressed tiles ar e then transferred to the press dryer, where the tiles are dried. The press dryer, which is fired with natural gas, operates at an inlet temp erature of about 320o to 340oF and an outlet temperature of about 275oF. The duration of th e dryer cycle is found in Item

No. 5 of the Confidential Addendu m to the report. Additional details on the forming and drying steps are found in the Tile Pressing and Tile Drying sections of the attachment.

4. Glazing

The dried tiles are transferred to the glazing area, where they are moistened and a base coating (engobe) is applied. Glazes and glaze pastes are then alternately applied in a series of several steps. Data on the maximum number of glaze application steps is found in Item No. 6 of the Confidential Addendum to the report. Gl azes are applied by spray, while glaze pastes are applied by using a cylinder-mounted silk scree n. The glazed tiles are stacked on racks and automated carts pick up the racks and transfer them the kiln. Additional detail s on the glazing process are found in the Glazing section of the attachment.

5. Firing

After glazing, the tiles are fired in fast fire roller kilns. Plant No. 1 has four natural gas-fired fast fire roller kilns, only three of which are currently in operation. Plant No. 2 has one natural gas-fired double layer kiln for firing the gr een tiles. The double layer kiln consists of two kilns stacked one on top of the other that operate independently of each other. All of the kilns

are fast fire roller kilns. Info rmation on the duration of the firing cycles is found in Item No. 7 of the Confidential Addendum to the report. The fi rst section of the double layer kiln acts as a dryer for the green tiles. Information of the fi ring temperature ranges is found in Item No. 8 of the Confidential Addendum to the report. After firi ng, the tiles enter the coo ling zone of the kiln. The tiles exiting the kiln are st acked and transferred to the insp ection station. Additional details on the firing step are found in the Firing section of the attachment.

6. Inspection and Packaging

The fired tiles are inspected and graded, then packaged for shipping. Additional details on the inspection and packaging of finished tiles are found in the Selection and Packaging

section of the attachment.

C. Emissions and Controls

Emissions from the kilns include hydr ogen fluoride (HF), hydrogen chloride (HCl), sulfur dioxide (SO 2 ), particulate matter (PM), and products of combustion. The PM may include HAP metals from the glazes. None of the k ilns at the facility ar e equipped with emission controls. All glaze spray booths are controlled with fabric filte rs. The body preparation batching operations, ball mills, spray dryers, glaze prepara tion operations, and presses also are controlled

with fabric filters.Attachment 1

Non-Confidential Process Description provided by American Marazzi Tile, Inc.A MERICAN M ARAZZI T ILE

, I NC

.

P ROCESS D ESCRIPTION

NONMETALLIC MINERAL PROCESSING

, This includes the receipt of the raw materials by truck (shale, clay, ne pheline syenite, feldspar, talc, and sand) and their storage in one of two raw material storage areas. These materials are moved by a front-end loader and lo aded into a feed hopper. With the exception of the shale and clay, these materials are metered directly out onto a conveyor system that transports the material to storage silos. The shale and clay material is processed th rough a crusher prior to being conveyed to a storage silo. From the storage silos, raw materials are transported by conveyors to surge hoppers that feed the individual continuous mills. These materials are then metered into a continuous ball mill where water is added and then milled to the desired consistency and viscosity creating a mud like slurry call ed "slip." Upon completion of th e milling process, the slip is pumped in to a concrete slip tank where it is stored before spray drying. This process does not have any potential to emit HAPS.

S PRAY D RYING

,
The slip is then pumped, at high pressure, into one of three spray dryers (atomizer) through a series of nozzles that cause the slip to be sprayed as a fine mist into an encl osed hot air stream that dries the slip to a fine powder, with a low moisture content, that is known by two synonymous terms "Body Material" or "Prill". This prill material is transpor ted via conveyor systems to the prill silos. The spray dryers are fueled by natu ral gas. The emission of HAPs is not anticipated to occur from this process.

T ILE B ODY S TORAGE AND C ONVEYING

,
The tile body material "prill" is stored in silos until needed in production. When needed the prill is fed from the bottom of the storage silos onto to a series of conveyor systems that transports the prill to the presses. A diverter is used to cha nnel the body material to the appropriate press surge hopper. This process does not ha ve any potential to emit HAPS.

T ILE P RESSING

,
The prill is gravity fed from the press surge hoppers into the press di es and pressed into individual tiles (final shape) of various sizes by means of an automatic hydraulic press. This process does not have any potential to emit HAPS.

September 10,2008American Marazzi Tile, Inc Process Description September 10, 2008

T ILE D RYING ,
The individual pressed tiles are transported by roller conveyor to either a vertical dryer or a horizontal five channel roller dryers to further reduce the moisture content of individual pressed

tiles. These dried tiles are referre d to as "green tile" and this drying process provides the green tiles with sufficient strength to undergo glazing and tr ansfer to the kilns. Press dryers are fueled by natural gas. The emission of HAPs is not anticipated to occur from this process.



### G LAZE 

### P REPARATION



### ,
Glazes and glaze pastes, which are two distinct t ypes of glazing material, are prepared in this step. Frits, small amounts of clays, stains a nd other material are batched and milled until the desired consistency and color is achieved. Glaze pa stes involve taking sets amount of material and mixing them together until the desired paste like consistency and color are achieved. Minor amounts of HAP metals may be emitted from this process.

G LAZING

,
This manufacturing step consists of the applica tion of thin uniform coats of two distinct types of glazing material; glaze and glaze paste to the green tile. Glazes may be applied by means of an air spray, bell (waterfall), or rotating disc in a totally enclosed environment. Glaze pastes are applied by means of either a static or ro tating silkscreen technique. Normally, several layers of glazes and glaze pastes are applied to each tile to prov ide the final decorative surface. Minor amounts of HAP metals may be emitted from this process.

F IRING ,
This step involves heating of the tiles to v itrify (make glass-like) and fuse (bond) the glaze material permanently to the surf ace of the tile body. The green tiles are fed into a fast fire roller kiln and fired according to a predetermined temperature curve that exposes the tiles to a maximum temperature of approxima tely 2,000°F and then cooled rapidly by an indirect cooling system. This process results in the formation of an attractive produc t in which the glazing materials and tile body is fused permanently together . Natural gas is used as fuel to heat the kilns. Emissions of HAPs (Hydrogen Chloride and Hydrogen Fluoride are emitted during this process. The emission of HAP metals are not anticipated to occu r from this process.

S ELECTION AND P ACKAGING ,
In this process tile is inspected and graded for conformity to established product quality standards. After grading, the tile is boxed and pall etized. Pallets of tile are then stored prior to sale and shipment to customers. No air emissi ons are associated with this operating scenario. This process does not have any potential to emit HAPS.

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