Rockwool
Mineral wool, also known as mineral cotton, silicate cotton, stone wool, slag wool, rockwool, and rock wool, is an inorganic substance used for insulation and filtering.
Mineral wool is a furnace product of molten rock, at a temperature of about 1600°C, through which is blown a stream of air or steam. 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. It is a poor conductor of heat and sound, is fire-proof and insect-proof, and therefore is ideal as a building insulation. Other uses are in resin bonded panels, growth medium in hydroponics, and as a filtering medium.
Precautions need to be made when handling the 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.
The EU risk and safety phrases associated with this material 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.
Use in Hydroponics
Mineral wool is used in hydroponics 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 not suitable to plant growth. This requires correcting or conditioning. Conditioned mineral wool has a stable pH over long periods of time.
