Sillimanite

CAS Number: 12141-45-6

Molecular Formula: Al₂SiO₅

Industry: Refractories, Ceramics, Foundry, Glass

About Sillimanite

Sillimanite is a naturally occurring aluminium silicate mineral valued for its exceptional refractoriness, thermal stability, and resistance to thermal shock. Universally used in refractory linings, kiln furniture, foundry products, ceramics, glass manufacturing, and high-temperature insulation materials. The industria...

Sillimanite Specifications

CAS Number

12141-45-6

Molecular Formula

Al₂SiO₅

Molecular Weight

162.05 g/mol

IUPAC Name

oxo(oxoalumanyloxy)silanyloxyaluminum

Canonical SMILES

O=[Al]O[Si](=O)O[Al]=O

InChI Key

WHNFFVNRXGCOJZ-UHFFFAOYSA-N

InChI

InChI=1S/2Al.O5Si/c;;1-6(2,3)4-5

EINECS Number

235-253-5 (Aluminosilicate mineral)

MDL Number

MFCD00145239

HSN No

25085031 (Lumps) 25085032 (Fines including sand) 25085039 (Other)

CAS Number

12141-45-6

Molecular Formula

Al₂SiO₅

Molecular Weight

162.05 g/mol

IUPAC Name

oxo(oxoalumanyloxy)silanyloxyaluminum

Canonical SMILES

O=[Al]O[Si](=O)O[Al]=O

InChI Key

WHNFFVNRXGCOJZ-UHFFFAOYSA-N

InChI

InChI=1S/2Al.O5Si/c;;1-6(2,3)4-5

EINECS Number

235-253-5 (Aluminosilicate mineral)

MDL Number

MFCD00145239

HSN No

25085031 (Lumps) 25085032 (Fines including sand) 25085039 (Other)

Appearance

Gray, brown, greenish, or white crystalline mineral; available as granules or powder

Molecular Weight

162.05 g/mol

Alumina (Al₂O₃) Content

Typically 55–63%

Silica (SiO₂) Content

Typically 35–40%

Crystal System

Orthorhombic

Density

3.2–3.3 g/cm³

Mohs Hardness

6.5–7.5

Melting Point

Approximately 1,540–1,560°C (decomposes and transforms to mullite and silica at high temperatures)

Odor

Odorless

Color

Gray, brown, greenish, or white

Not applicable (insoluble solid)

Electrical Conductivity

Very low (electrical insulator)

Thermal Conductivity

Low to moderate

Electrical Conductivity

Very low (electrical insulator)

Thermal Conductivity

Low to moderate

Magnetic Properties

Non-magnetic

Chemical properties

Chemically stable under normal storage and handling conditions

GHS statement

Bulk sillimanite is generally not classified as hazardous under the (GHS). The primary hazard arises from airborne respirable dust generated during crushing, grinding, machining, or handling. If the product contains respirable crystalline silica (quartz), additional hazard classifications may apply depending on its concentration.

Hazard Statement

H350:May cause cancer by inhalation. H372:Causes damage to lungs through prolonged or repeated inhalation exposure.

Regulatory statement₹

Sillimanite is generally not regulated as a dangerous good under ADR, RID, IMDG, IATA, or DOT regulations when transported as granules, powder, or refractory-grade mineral.

Precautionary Statement Codes

P260, P264, P270, P271, P284, P301+P316, P304+P340, P316, P320, P321, P330, P403+P233, P405, and P501

Hazard Classes and Categories

Acute Tox. 2 (93.5%)

Refractory Industry

A primary raw material used to manufacture high-alumina bricks, castables, and furnace linings due to its high temperature resistance and low thermal expansion

Glass Industry

An essential source of alumina used in glass melting tank furnaces to enhance the strength, hardness, and chemical resistance of glass products

Ceramic Industry

A functional additive incorporated into ceramic formulations, such as porcelain and electrical insulators, to improve thermal shock resistance and high-temperature performance