Common Ingredients: Vitreous Glazes (unleaded)
Representative Manufacturers
Used in Product Categories: Tile Components, Sanitary Ware Components , Tiles, Sanitary Ware, Flooring, Ceramic Floor Tiles, Toilet Tanks, One Piece Toilets & Toilet Bowls, Toilet Seats
Content status: Sufficient Content Record
Description:
Vitreous glazes seal clay-based ceramic products and provide a shiny and smooth surface. This glass-like coating can be transparent, colored or opaque, and can prevent water from being absorbed into the clay beneath.
Vitreous glazes are mixtures of minerals, clays, and frits (which in turn are primarily metal oxides, blended and smelted).
"Base glaze formulations usually contain frits of different nature in varying proportions (30-60%), and other non-fritted constituents (usually crystalline aggregates) of very different natures and characteristics, in accordance with the targeted final glaze properties. Some of these constituents such as feldspars, nephelines, and zinc oxide contribute together with the frits to forming the glassy matrix of the glze. Others, however, like zirconium silicate and corundum hardly dissolve in the glassy phase. Their function is to enhance glaze abrasion resistance to a certain extent, besides acting as opacifying (zirconium (IV) silicate) or matting agents (aluminum oxide)." (Esmalglass)
In 1997, EPA noted, “Basic carbonate white lead has been the preferred leaded glaze ceramic manufacture for hundreds of years… However, white lead and other lead oxides are more soluble than other forms of lead, and because the lead leaches out over time, they are being phased out by the industry. The ceramics industry is addressing this solubility problem by adding lead to glaze in frit form.” (EPA 1997 - lead.pdf ) Since then, the use of lead oxides in frits has also declined.
Some floor and wall tile manufacturers do not use lead oxide or other lead substances in glazes.
This record for vitreous glazes evaluates mixtures that do not contain lead.
Glazes account for approximately 1-6% of the overall tile, depending upon the application (Industrieverband Keramishche EPD, Sectoral Life Cycle Analysis of Ceramic Tile, Comparative Life Cycle Anlaysis of Flooring Materials). Typically, wall tiles have greater glaze content than floor tiles, however that can vary by manufacturer.
This percentage can be higher in sanitaryware. One industry source estimates a toilet and tank combination can contain 6.5 lbs of glaze (American Standard patent).
Direct Content Hazards:
Potential Residual Hazards:
See Process Chemistry Research tab for details on residuals and other substances used in manufacture.
Common Contents:
Material | % Wt. Part | % Wt. Whole | Hazard | GreenScreen | Renewable | ||||
---|---|---|---|---|---|---|---|---|---|
Substance | Residual | Manufacturing | |||||||
Frits, chemicals (unleaded) | 30.00 - 62.00 % | 30.00 - 62.00 % | LT-P1 | ||||||
[68476-25-5] FELDSPAR | 20.00 - 30.00 % | 20.00 - 30.00 % | LT-UNK | ||||||
[37244-96-5] NEPHELINE SYENITE | 10.00 - 30.00 % | 10.00 - 30.00 % | LT-UNK | ||||||
[1303-86-2] Boric Oxide | 10.00 - 20.00 % | 10.00 - 20.00 % | LT-1 | ||||||
[1332-58-7] KAOLIN CLAY | 4.00 - 6.00 % | 4.00 - 6.00 % | LT-UNK | ||||||
[10101-52-7] Zirconium silicate | 2.00 - 30.00 % | 2.00 - 30.00 % | LT-UNK | ||||||
[1344-28-1] ALUMINUM OXIDE | 0.50 - 40.00 % | 0.50 - 40.00 % | 2 | ||||||
[1314-13-2] ZINC OXIDE | 0.50 - 20.00 % | 0.50 - 20.00 % | 1 |
Process Chemistry - Known or Potential Residuals:
Material | Hazard | Type | Frequency | % Wt. Part | % Wt. Whole | Notes | ||||
---|---|---|---|---|---|---|---|---|---|---|
Substance | Residual | Manufacturing | ||||||||
[1344-28-1] ALUMINUM OXIDE - from FELDSPAR | Component | Integral (known) | Unknown | Unknown | ||||||
[1344-28-1] ALUMINUM OXIDE - from KAOLIN CLAY | Reactant | Integral (known) | 37.40 - 39.60 % | Unknown | ||||||
[1344-28-1] ALUMINUM OXIDE - from Frits, chemicals (unleaded) | Component | Frequent (known) | Unknown | Unknown | ||||||
[1317-70-0] Anatase titanium dioxide - from KAOLIN CLAY | Component | Integral | Unknown | Unknown | ||||||
[1309-64-4] ANTIMONY TRIOXIDE - from Frits, chemicals (unleaded) | Component | Frequent | 0.12 - 0.88 % | Unknown | ||||||
[513-77-9] BARIUM CARBONATE - from Frits, chemicals (unleaded) | Component | Frequent (known) | Unknown | Unknown | ||||||
[1304-28-5] BARIUM OXIDE, ANHYDROUS - from FELDSPAR | Component | Integral (known) | Unknown | Unknown | ||||||
[1304-28-5] BARIUM OXIDE, ANHYDROUS - from Frits, chemicals (unleaded) | Component | Frequent | Unknown | Unknown | ||||||
[1303-86-2] Boric Oxide - from Frits, chemicals (unleaded) | Component | Occasional/Rare (known) | Unknown | Unknown | ||||||
[1305-78-8] CALCIUM OXIDE - from FELDSPAR | Component | Integral (known) | 0.70 - 1.40 % | Unknown | ||||||
[1305-78-8] CALCIUM OXIDE - from KAOLIN CLAY | Reactant | Frequent (known) | 0.00 - 0.20 % | Unknown | ||||||
[12136-45-7] dipotassium oxide - from FELDSPAR | Component | Integral (known) | 0.10 - 0.70 % | Unknown | ||||||
[12136-45-7] dipotassium oxide - from KAOLIN CLAY | Reactant | Integral (known) | 44.40 - 45.70 % | Unknown | ||||||
[12136-45-7] dipotassium oxide - from Frits, chemicals (unleaded) | Component | Frequent (known) | Unknown | Unknown | ||||||
[1345-25-1] FERROUS OXIDE - from FELDSPAR | Component | Frequent (known) | 0.10 % | Unknown | ||||||
[1345-25-1] FERROUS OXIDE - from KAOLIN CLAY | Pollutant/ Contaminant | Integral (known) | 0.40 - 0.80 % | Unknown | ||||||
[12057-24-8] Lithium oxide - from Frits, chemicals (unleaded) | Component | Frequent (known) | Unknown | Unknown | ||||||
[1309-48-4] MAGNESIUM OXIDE - from FELDSPAR | Component | Integral (known) | Unknown | Unknown | ||||||
[1309-48-4] MAGNESIUM OXIDE - from Frits, chemicals (unleaded) | Component | Frequent (known) | Unknown | Unknown | ||||||
[1309-48-4] MAGNESIUM OXIDE - from KAOLIN CLAY | Reactant | Frequent (known) | 0.00 - 0.10 % | Unknown | ||||||
[1314-56-3] PHOSPHORUS PENTOXIDE - from KAOLIN CLAY | Reactant | Frequent (known) | 0.00 - 0.30 % | Unknown | ||||||
[14808-60-7] QUARTZ - from KAOLIN CLAY | Component | Integral (known) | 1.00 % | Unknown | ||||||
[7631-86-9] SILICA, AMORPHOUS - from Frits, chemicals (unleaded) | Component | Frequent (known) | Unknown | Unknown | ||||||
[7631-86-9] SILICA, AMORPHOUS - from FELDSPAR | Component | Integral (known) | 60.70 - 68.30 % | Unknown | ||||||
[7631-86-9] SILICA, AMORPHOUS - from KAOLIN CLAY | Reactant | Integral (known) | 44.40 - 45.70 % | Unknown | ||||||
[11126-22-0] Silica, vitreous - from FELDSPAR | Component | Integral (known) | Unknown | Unknown | ||||||
[1313-59-3] SODIUM OXIDE - from Frits, chemicals (unleaded) | Component | Frequent (known) | Unknown | Unknown | ||||||
[1313-59-3] SODIUM OXIDE - from FELDSPAR | Component | Integral (known) | 3.00 - 9.80 % | Unknown | ||||||
[1314-11-0] Strontium oxide - from FELDSPAR | Component | Integral (known) | Unknown | Unknown | ||||||
[18282-10-5] Tin Oxide - from Frits, chemicals (unleaded) | Component | Frequent (known) | 0.20 % | Unknown | ||||||
[13463-67-7] Titanium dioxide - from KAOLIN CLAY | Pollutant/ Contaminant | Integral (known) | 0.40 - 1.70 % | Unknown | ||||||
[1314-13-2] ZINC OXIDE - from Frits, chemicals (unleaded) | Component | Frequent (known) | 0.50 - 30.00 % | Unknown | ||||||
[1314-23-4] ZIRCONIUM DIOXIDE - from Frits, chemicals (unleaded) | Component | Frequent (known) | Unknown | Unknown |
Process Chemistry - Other:
Material | Hazard | Type | Frequency | % Wt. Part | % Wt. Whole | Notes | ||||
---|---|---|---|---|---|---|---|---|---|---|
Substance | Residual | Manufacturing | ||||||||
[21645-51-2] Alumina trihydrate - from ALUMINUM OXIDE | Reactant | Frequent | Unknown | Unknown | ||||||
[1318-16-7] BAUXITE - from ALUMINUM OXIDE | Reactant | Integral | Unknown | Unknown | ||||||
[10043-35-3] BORIC ACID - from Boric Oxide | Reactant | Frequent | Unknown | Unknown | ||||||
[1302-42-7] SODIUM ALUMINATE - from ALUMINUM OXIDE | Reactant | Frequent | Unknown | Unknown | ||||||
[1310-73-2] Sodium hydroxide - from ALUMINUM OXIDE | Reactant | Frequent | Unknown | Unknown | ||||||
[1313-59-3] SODIUM OXIDE - from KAOLIN CLAY | Reactant | Integral | 0.06 - 0.10 % | Unknown | ||||||
[1330-43-4] SODIUM TETRABORATE - from Boric Oxide | Reactant | Frequent | Unknown | Unknown | ||||||
[7664-93-9] SULFURIC ACID - from Boric Oxide | Reactant | Frequent | Unknown | Unknown | ||||||
[7440-66-6] ZINC - from ZINC OXIDE | Reactant | Frequent | Unknown | Unknown | ||||||
[1314-98-3] ZINC SULFIDE - from ZINC OXIDE | Reactant | Occasional/Rare | Unknown | Unknown | ||||||
[14940-68-2] Zircon (Zr(SiO4)) - from Zirconium silicate | Reactant | Integral | Unknown | Unknown |
GreenScreen for Safer Chemicals Full Assessment: None available
Highest concern GreenScreen score : Benchmark 1
Cradle to Cradle Certified™ List Hazards
What are C2C hazards and what do these colors mean?
How to Use These Scores in a C2C Assessment
Acute and Chronic Tox. | Acute Aquatic Tox. | Chronic Aquatic Tox. | ||||||||||||||||||||||||
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C | M | R+D | E | O | D | I | O/D/I | N | IrS+IrE | SnS+SnR | Fish | Inv. | Alg. | Any | Fish | Inv. | Alg. | Any | T | P | B | Climate | Organohalogen | Toxic Metal | Other | Mult |
R | - | R | - | - | - | ? | R | - | Y | R | ? | ? | ? | R | - | - | - | R | ? | R/Y | - | G | NL | NL | - | R |
Full Hazard List By Endpoint:
- Chen, Zheng, James Michael Mchale. "Antimicrobial glaze and porcelain enamel via double layer glaze with high zinc content." American Standard Int Inc, Applicant. Patent WO2006130308 A2. December 7, 2006.
- Comparative Life Cycle Assessment of flooring materials: ceramic versus marble tiles (2001)
- Economic Impact Analysis of the Clay Ceramics Manufacturing NESHAP: Final Rule (EPA 2003)
- Esmalglass: "Obtaining Smooth, White Floor Tile Glazes from Zirconium-Free Frits" (Castellon - Spain - Qualicer 98)
- Ferro Corp., "Ceramic tile and glaze for use thereon," US Patent No. US 6,174,608 B1 (2001)
- Ferro Corp., "Tile Glaze," US Patent No. US 6,132,832 (2000)
- Ferro Corp., "Transparent Tile Glaze," US Patent Application No. US 2005/0130824 A1
- Industrieverband Keramische Fliesen und Platten e.V. Ceramic Tiles EPD
- M. Potter, "Feldspar and Nepheline Syenite," US Geological Survey Minerals Yearbook 2002
- Matsumoto, Akio and Toshinya Nishikawa. "Vitreous china, method for preparing the vitreous china, sanitary-ware produced therefrom and glaze therefor." Toto Ltd., Assignee. Patent US5372976 A. December 13, 1994.
- North Carolina Geological Survey: "Feldspar"
- Office of Air Quality Planning and Standards, Economic Impact Analysis of the Clay Ceramics Manufacturing NESHAP: Final Rule, US Environmental Protection Agency, February 2003
- Rio Tinto Minerals: "Borates in glazes and enamels" (undated)
- Sectoral Life Cycle Analysis of Ceramic Tile
- Torrecid Group - Czech Republic product page
- US AID: "Privatization and Technical Assistance Program for the Kardzhali Region of Bulgaria" (1996)
- US Patent: "Antimicrobial glaze and porcelain enamel via double layer glaze with high zinc content," American Standard (2006)