Date: October 6, 2008 

 (Finalized: December 8, 2008) 

Subject: Site Visit – American Marazzi 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 emission standards for hazardous air 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. 2222 
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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. Plant 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 No.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 capacity and throughput rate 

will be different than the design capacity for the plant. They also noted that Plant No. 2 is not 

covered in American Marazzi’s submittal to the July-August 2008 information collection request 

for the clay ceramics manufacturing industry. 

 American Marazzi primarily uses shale, clay, crushed granite, and sand to produce 

red body ceramic and porcelain tiles, and uses clay, 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 for porcelain must be less than 0.5 percent. 

 Both plants operate 24 hours per day, 7 days per week. The facility employs a total 

of about 300 people in their manufacturing operations. 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. 

 
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 B. Process

 The processing steps used at American Marazzi include raw material receiving and 

processing, body and glaze preparation, tile forming, drying, glazing, firing, product inspection, 

and packaging. Attachment 1 is a process description provided by American Marazzi at the time 

of the visit. The following paragraphs supplement 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 description of how these materials are received, 

stored, and milled to form a slurry, which is referred 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 natural 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. Otherwise, it is difficult to meet the size and quality 

specifications for larger ceramic tiles. American Marazzi operates three 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 the slip spray and dries the slip, reducing the 

moisture content. Data on moisture content ranges are 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 operating temperatures prevents the formation of 

hydrogen fluoride and hydrogen chloride. After drying, the material is discharged 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 preparation area that serves both plants. The raw 

materials used to make glazes and glaze pastes include 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-weighed and transferred to a ball mill for mixing grinding. The glazes 

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

section of the attachment. 

3. Forming and Drying 

 In the forming area, the spray-dried powder 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 seven press lines, and Plant No. 2 operates three 
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press lines. The pressed tiles are then transferred to the press dryer, where the tiles are dried. 

The press dryer, which is fired with natural gas, operates at an inlet temperature of about 320o to 

340oF and an outlet temperature of about 275oF. The duration of the dryer cycle is found in Item 

No. 5 of the Confidential Addendum 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. Glazes are applied by spray, while glaze pastes are 

applied by using a cylinder-mounted silk screen. The glazed tiles are stacked on racks and 

automated carts pick up the racks and transfer them the kiln. Additional details 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 green 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. Information on the duration of the firing cycles is found in Item No. 7 of 

the Confidential Addendum to the report. The first section of the double layer kiln acts as a 

dryer for the green tiles. Information of the firing temperature ranges is found in Item No. 8 of 

the Confidential Addendum to the report. After firing, the tiles enter the cooling zone of the kiln. 

The tiles exiting the kiln are stacked and transferred to the inspection 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 hydrogen fluoride (HF), hydrogen chloride (HCl), 

sulfur dioxide (SO2), particulate matter (PM), and products of combustion. The PM may include 

HAP metals from the glazes. None of the kilns at the facility are equipped with emission 

controls. All glaze spray booths are controlled with fabric filters. The body preparation batching 

operations, ball mills, spray dryers, glaze preparation operations, and presses also are controlled 

with fabric filters.
Attachment 1 

Non-Confidential Process Description 

provided by American Marazzi Tile, Inc. 
AMERICAN MARAZZI TILE, INC.

PROCESS DESCRIPTION

NONMETALLIC MINERAL PROCESSING,

This includes the receipt of the raw materials by truck (shale, clay, nepheline 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 loaded 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 through 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 called "slip." Upon completion of the 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.

SPRAY DRYING,

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 enclosed 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 transported via conveyor systems to the 

prill silos. The spray dryers are fueled by natural gas. The emission of HAPs is not anticipated 

to occur from this process.

TILE BODY STORAGE AND CONVEYING,

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 channel the body material to the appropriate press surge 

hopper. This process does not have any potential to emit HAPS.

TILE PRESSING,

The prill is gravity fed from the press surge hoppers into the press dies 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 10,2008
American Marazzi Tile, Inc 

Process Description September 

10, 2008

TILE DRYING,

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 referred to as "green tile" and this drying process provides the green 

tiles with sufficient strength to undergo glazing and transfer to the kilns. Press dryers are fueled 

by natural gas. The emission of HAPs is not anticipated to occur from this process.

GLAZE PREPARATION,

Glazes and glaze pastes, which are two distinct types of glazing material, are prepared in this 

step. Frits, small amounts of clays, stains and other material are batched and milled until the 

desired consistency and color is achieved. Glaze pastes 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.

GLAZING,

This manufacturing step consists of the application 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 rotating silkscreen technique. Normally, several 

layers of glazes and glaze pastes are applied to each tile to provide the final decorative surface. 

Minor amounts of HAP metals may be emitted from this process.

FIRING,

This step involves heating of the tiles to vitrify (make glass-like) and fuse (bond) the glaze 

material permanently to the surface 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 approximately 2,000°F and then cooled rapidly by an indirect cooling 

system. This process results in the formation of an attractive product 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 occur from this process.

SELECTION AND PACKAGING,

In this process tile is inspected and graded for conformity to established product quality 

standards. After grading, the tile is boxed and palletized. Pallets of tile are then stored prior to 

sale and shipment to customers. No air emissions are associated with this operating scenario. 

This process does not have any potential to emit HAPS.

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