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Encyclopedia > Mineral wool

Mineral wool, means fibres made from minerals or metal oxides, be they synthetic or natural. In industry use, MMMF (man-made-mineral-fibres) generally refer to synthetic materials. This includes fibreglass, ceramic fibres and also rockwool, also known as stone wool, and rock wool. Mineral wool is an inorganic substance used for insulation and filtering. A common mistake is to believe that fibreglass and ceramic fibres are NOT mineral wools, but they are by virtue of their consisting of minerals or metal oxides. Minerals are natural compounds formed through geological processes. ... Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily forms positive ions (cations) and has metallic bonds. ... The term Thermal Insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ... In chemistry and common usage, a filter is a device (usually a membrane or layer) that is designed to block certain objects or substances while letting others through. ...

Contents

Manufacture of stone wool

Stone wool is a furnace product of molten stone, at a temperature of about 1600°C, through which is blown a stream of air or steam. More high tech production techniques are based on spinning molten rock (lava) on high speed spinning wheels. (compare with candy floss) The final product is a mass of fine intertwined fibres with a typical diameter of 6 to 10 micrometres. Mineral wool may contain a binder and an oil to reduce dusting and making it water repellent (hydrophobic). The rocky side of a mountain creek near Orosí, Costa Rica. ... AIR is a three-letter abbreviation with multiple meanings, as described below: The Annals of Improbable Research, a monthly magazine devoted to scientific humour All India Radio - Indias Government Radio service AIR, a popular electronica band from France. ... In physical chemistry, and in engineering, steam refers to vaporized water. ... Spinning cotton candy on a kiosk at a funfair. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the size of a droplet of mist or fog. ... A binder is a material used to bind together two or more other materials in mixtures. ... Mineral oil or liquid petrolatum is a by-product in the distillation of petroleum to produce gasoline. ...


Usage

The fibres themselves are excellent conductors of heat, but they package air so well, that when pressed into rolls and sheets, rockwool makes for an excellent and reliable insulator. Batts, sheets and roll made of rockwool are a poor conductor of heat and sound. Fire resistive properties for mineral wools is given here in descending order: In physics, heat, symbolized by Q, is defined as energy in transit. ...

  1. fibreglass,
  2. stone wool,
  3. ceramic fibres.

No conventional building materials, including mineral wool are immune to the effects of fire of sufficient duration or intensity. However, each of the aforementioned three wools make common components in passive fire protection systems, such as in spray fireproofing, stud cavities in drywall assemblies required to have a fire-resistance rating, packing materials in firestops and more. // Building material is any material which is used for a construction purpose. ... Fire-resistance rated wall assembly with fire door, cable tray penetration and intumescent [1] cable coating. ... Fireproofing, a passive fire protection measure, subject to bounding, refers to the act of making materials or structures more resistant to fire, or to those materials themselves. ... A firestop is a passive fire protection system of various components used to seal openings in fire-resistance rated wall and/or floor assemblies through bounding. ...


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, growth medium in hydroponics, filler in compounds for gaskets, brake pads, in plastics in the automotive industry and as a filtering medium. {{[[Unreferenced}} [[Image:Hydroponic onions nasa. ...


Use in hydroponics

Mineral wool is used for its ability to hold large quantities of water and at the same time maintain a high percentage of air as well. This aids root growth and nutrient uptake. The fibrous nature of mineral wool also provides a good mechanical structure to hold the plant stable. Mineral wool has a high pH, which is unsuitable to plant growth. This requires correcting or conditioning. Conditioned mineral wool has a stable pH over long periods of time. pH is a measure of the acidity of a solution in terms of activity of hydrogen ions (H+). For dilute solutions, however, it is convenient to substitute the activity of the hydrogen ions with the molarity (mol/L) of the hydrogen ions (however, this is not necessarily accurate at higher...


Safety of material

Precautions need to be taken when handling a fibre product as it can be absorbed into the body by inhalation. It can also irritate the eyes, skin and respiratory tract. Prolonged exposure could lead to long term effects and it is considered a possible carcinogen to humans. This effect may depend upon the fibre diameter and length, chemical composition and persistence within the body. Closeup of a blue-green human eye. ... In zootomy and dermatology, skin is an organ of the integumentary system made up of multiple layers of epithelial tissues that guard underlying muscles and organs. ... In humans the respiratory tract is the part of the anatomy that has to do with the process of respiration or breathing. ... In pathology, a carcinogen is any substance or agent that promotes cancer. ...


High bio soluble fibres (HT-fibres) are produced that do not cause damage to the human cell. IARC (the International Agency for Research on Cancer) has reviewed the carcinogenicity of man made mineral fibres in October 2002. These newer biosoluble materials have been tested for carcinogenicity and most are found to be non-carcinogenic, or to cause tumours in experimental animals only under very restricted conditions of exposure. The IARC Monographs working group concluded that only the more biopersistent materials remain classified by IARC as possible human carcinogens (Group 2B). 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, rock (stone) wool and slag wool are considered not classifiable as to carcinogenicity to humans (Group 3).


The EU risk and safety phrases associated with this material in general are:

  • R38 – Irritating to the skin
  • R39 – Danger of very serious irreversible effects
  • R40 – Possible risk of irreversible effects
  • S36/37 – Wear suitable protective clothing and gloves.

All European produced rock (stone)wool and glass wool is bio soluble and R39 and R40 do not apply. For these products only the risk phrase R38 remains. This irritation to the skin however is not a chemical irritation but only a temporal mechanical irritation, comparable with exposure of the skin to straw, grass or hay.


Controversy exists over these rulings, as the majority of test results upon which they are based have typically been provided by the industry that makes the fibres. Test results that contravene such results were deemed inadmissible to IARC as submission by whistleblowers are not sanctioned by the party paying for the tests. Still by following common sense and industrial guidelines to prevent breathing of the fibres, it is possible to reduce the likelihood of pathology.


External link

http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc01/icsc0194.htm


  Results from FactBites:
 
Method and means for producing mineral wool - Patent 4971615 (0 words)
A method and means for producing mineral wool from coal slag is described wherein molten coal slag is transferred from a coal slag tank in an electrical generation plant.
Mineral wool is a fibrous material normally made from molten rock or slag with its main use being as an insulating material.
The mineral wool producing apparatus of this invention is referred to generally by the reference numeral 10 and includes a slag transfer device 12, slag heater 14, fiberizing apparatus 16, and a fiber collection apparatus 18.
Sage Learning Center: Mineral Wool/Rock Wool Insulation (0 words)
Mineral wool was at one time the most common type of insulation, but by the 1970s, fiberglass overtook its popularity.
Mineral Wool is spun from mineral mining waste into felts, blankets and batts.
Mineral wool is non-combustible and is particularly useful in high heat areas to prevent the spread of possible fires.
  More results at FactBites »


 

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