142844-00-6

Basic information

• Product Name: Refractories, fibers, aluminosilicate
• Synonyms: Refractories, fibers, aluminosilicate;ALUMINOSILICATE (VITREOUS)
• CAS NO: 142844-00-6
• Molecular Formula: Al6O13Si2
• Molecular Weight: 426.052428
• Mol File: 142844-00-6.mol
• Article Data: 0

Chemical Properties

• Melting Point: >1650°C
• Appearance: /
• Density: 2.6-2.7 g/cm3
• Storage Temp.: Store at +5°C to +30°C.
• CAS DataBase Reference: Refractories, fibers, aluminosilicate(CAS DataBase Reference)
• NIST Chemistry Reference: Refractories, fibers, aluminosilicate(142844-00-6)
• EPA Substance Registry System: Refractories, fibers, aluminosilicate(142844-00-6)

Safety Data

• Hazard Codes: T
• Statements: 49
• Safety Statements: 53-45
• WGK Germany: 3
• Hazardous Substances Data: 142844-00-6(Hazardous Substances Data)

Usage

Description

Refractories, fibers, aluminosilicate, also known as aluminosilicate wool (ASW) or refractory ceramic fibers (RCF), are amorphous synthetic vitreous fibers (SVFs) that belong to a class of materials termed man-made mineral fibers. They are produced by melting alumina, silica, and other inorganic oxides, and then blowing or spinning these melts into fibers. These fibers are characterized by their low thermal conductivity, low heat storage, thermal shock resistance, lightweight, good corrosion resistance, and ease of installation.

Uses

Used in Industrial Applications:
Refractories, fibers, aluminosilicate is used as high-temperature insulating materials for various industrial applications, including furnace linings and components in the cement, ceramic, chemical, fertilizer, forging, foundry, glass, heat treating, nonferrous metals, petrochemical, power generation (cogeneration), and steel industries.
Used in Energy Conservation:
Refractories, fibers, aluminosilicate is used as insulation to reduce energy costs and greenhouse gas emissions, providing substantial energy savings when compared to conventional high-temperature insulation such as insulating firebrick.
Used in Passive Fire Protection:
Refractories, fibers, aluminosilicate is used as passive fire protection materials where thin, lightweight materials are needed to prevent flame penetration.
Used in Emission Control Applications:
Refractories, fibers, aluminosilicate is used in emission control applications such as heat shield insulation, catalytic converter support mat, and filtration media for airbag inflators.

Production Methods

Refractory ceramic fiber is produced from a mixture of sand and alumina or kaolin. Metal oxides such as titanium and zinc may be added, depending upon the final desired specifications (16d, 26). The raw materials are transferred to the furnace where the batch is melted. As the molten mix flows from the furnace, it is fiberized as it passes a stream of air and steam or falls on rotating disks. The fiber diameters are in the range of 0.5–10 μm, and have lengths up to several centimeters (69). Some raw fiber may be packaged in bulk for sale or for use in products containing RCF. Alternatively, raw fiber enters a chamber where it is sprayed with lubricating oil and allowed to settle onto a moving conveyor. This material moves through a needler, where opposing units of close-set needles are forced through the RCF, interlocking the fibers and forming a blanket. The blanket is conveyed through an oven to burn off the lubricating oil, then trimmed to the required dimensions, rolled, and boxed. Secondary processes involve the use of bulk fiber or blankets to produce additional products. These include vacuum- formed products, folded modules, braids and ropes, boards, and customer-specified shapes and use in catalytic converters, metal reinforcements, heat shields, brake pads, and airbags. Fibers may undergo transformation from amorphous to crystalline forms during use in high temperature applications. Therefore, exposures to these so-called after-use fibers may include mullite, cristobalite, or other crystalline phases.

Carcinogenicity

In 2002, IARC (16d) classified refractory ceramic fibers as “possibly carcinogenic to humans” (Group 2B), based on inadequate evidence of carcinogenicity in humans and sufficient evidence in experimental animals. The American Conference of Governmental Industrial Hygienists has designated RCF as a suspected human carcinogen (A3). Indulski et al. reported the numbers of occupational diseases diagnosed from 1984 to 1994 among 600 Polish workers employed in the manufacture of refractory ceramic fibers. No cases of lung cancer were cited. Lung fibrosis and silicosis were noted in four workers, ages 52–64 at diagnosis. The duration of employment ranged from 24 to 37 years preceding the manufacture of ceramic fibers; therefore, the authors note that the conditions could be related to earlier employment.

Environmental Fate

Numerous in vitro and in vivo studies have been conducted on both natural and synthetic fibers to try to understand and measure cytotoxicity, mutagenicity, and genotoxicity. Many of these studies have proven inconclusive, so mechanism(s) of action are still unclear. Other studies have indicated that aluminosilicate fibers are less active biologically than various forms of asbestos.

Toxicity evaluation

Aluminosilicate fibers are white fibrous solids, soluble to a degree in human lung fluid (see below). The usual physicochemical parameters relevant to fate and transport (e.g., solubility, vapor pressure, octanol–water partition coefficient, and Henry’s law constant) are not applicable or relevant; vapor pressure, octanol–water partition coefficient, and Henry’s law constant are exceedingly low and not measurable. Fibers are capable of being transported in the air and are removed by gravitational settling. The Member State Support Document submitted to the European Chemicals Agency in favor of listing aluminosilicate fibers as a substance of very high concern (SVHC) notes that environmental fate and hazard data were not relevant.