Mineral wool, also known as mineral fiber, mineral fibre, rock wool, rockwool, stone
wool, man-made mineral fibre, and man-made vitreous fiber, is a name for fiber materials
that are formed by spinning or drawing molten minerals.
Completely man-made fibers include glass wool and ceramic fiber.
Industrial applications of mineral wool include thermal insulation, filtration, soundproofing,
and hydroponic growth medium.
History Slag wool was first made in 1840 in Wales
by Edward Parry, "but no effort appears to have been made to confine the wool after production;
consequently it floated about the works with the slightest breeze, and became so injurious
to the men that the process had to be abandoned".
It was first produced commercially in 1871 at Georgsmarienhütte in Osnabrück Germany.
Manufacture Stone wool is a furnace product of molten
rock at a temperature of about 1600 °C, through which a stream of air or steam is blown.
More advanced production techniques are based on spinning molten rock in high-speed spinning
heads somewhat like the process used to produce cotton candy.
The final product is a mass of fine, intertwined fibres with a typical diameter of 6 to 10
micrometers.
Mineral wool may contain a binder, often food-grade starch, and an oil to reduce dustproduction.
Usage Though the individual fibers conduct heat
very well, when pressed into rolls and sheets, their ability to partition air makes them
excellent heat insulators and sound absorbers.
Though not immune to the effects of a sufficiently hot fire, the fire resistance of fiberglass,
stone wool, and ceramic fibers makes them common building materials when passive fire
protection is required, being used as spray fireproofing, in stud cavities in drywall
assemblies and as packing materials in firestops.
Mineral wools are unattractive to rodents, but will provide a structure for bacterial
growth if allowed to become wet.
Other uses are in resin bonded panels, as filler in compounds for gaskets, in brake
pads, in plastics in the automotive industry, as a filtering medium, and as a growth medium
in hydroponics.
Mineral fibers are produced in the same way, without binder.
The fiber as such is used as a raw material for its reinforcing purposes in various applications,
such as friction materials, gaskets, plastics, and coatings.
The heat the material can withstand is:
In hydroponics Mineral wool products can hold large quantities
of water and air that aid root growth and nutrient uptake in hydroponics; their fibrous
nature also provides a good mechanical structure to hold the plant stable.
The naturally high pH of mineral wool makes them initially unsuitable to plant growth
and requires "conditioning" to produce a wool with an appropriate, stable pH.
Safety of material Precautions need to be taken when handling
a fiber product, as it can irritate the eyes, skin, and respiratory tract.
This irritation to the skin is not a chemical irritation, but only a mechanical irritation,
comparable with exposure of the skin to bio-soluble materials such as straw, grass, or hay.
The International Agency for Research on Cancer has reviewed the carcinogenicity of man-made
mineral fibres in October 2002.
The IARC Monograph's working group concluded only the more biopersistent materials remain
classified by IARC as "possibly carcinogenic to humans".
These include refractory ceramic fibres, which are used industrially as insulation in high-temperature
environments such as blast furnaces, and certain special-purpose glass wools not used as insulating
materials.
In contrast, the more commonly used vitreous fibre wools, including insulation glass wool,
stone wool, and slag wool, are considered "not classifiable as to carcinogenicity in
humans".
High biosoluble fibres are produced that do not cause damage to the human cell.
These newer materials have been tested for carcinogenicity and most are found to be noncarcinogenic,
or to cause tumours in experimental animals only under very restricted conditions of exposure.
The IARC Monograph's working group "elected not to make an overall evaluation of the newly
developed fibres designed to be less biopersistent such as the alkaline earth silicate or high-alumina,
low-silica wools.
This decision was made in part because no human data were available, although such fibres
that have been tested appear to have low carcinogenic potential in experimental animals, and because
the Working Group had difficulty in categorizing these fibres into meaningful groups based
on chemical composition."
See also Risk and Safety Statements
Basalt fiber, a mineral fiber having high tensile strength
Asbestos, a mineral that is naturally fibrous References
External links Statistics Canada documents on shipments of
mineral wool in Canada Review of published data on exposure to mineral
wool during installation work by A Jones and A Sanchez Jimenez, Institute of Occupational
Medicine Research Report TM01 Assessment of airborne mineral wool fibres
in domestic houses by J Dodgson and others.
Institute of Occupational Medicine Research Report TM18