Dunite has a unique heat capacity, while it has a high thermal conductivity, i.e. the ability to quickly concentrate and release heat.
Natural stone is an invariable attribute of a Russian sauna with a stove. And just stones are often used in the decoration of the steam room. Today we will tell you about such an interesting stone as dunite, which will be an excellent choice for arranging baths and saunas, as it has a number of positive characteristics.
Dunite was discovered for the first time in New Zealand, near the Dun Mountains. This is precisely the reason for this name. Dunite is formed deep underground, below the earth’s crust, so it is absolutely safe from the point of view of the radiation background. Dunite belongs to ultrabasic stones, it contains from 30% to 45% silicon oxide, due to which the stone perfectly tolerates a large amount of heating and cooling, while not releasing toxic compounds.
The approximate chemical composition of dunite looks like this:
- MgO – about 38-50%
- SiO2 – 35-40%
- FeO – 3-6%
- Fe2O3 – 0.5-7%
- Al2O3 – up to 2.5%
- CaO – 0.5-1.5%
- Na2O – up to 0.3%
- К2О – up to 0.25%
Dunite is a granular stone. Most often, the granular structure is small, but it can be medium and even large. In color, the stone is not remarkable for anything special – gray, brownish, interspersed with green, black shades. If the stone contains inclusions of a metallic color, it means that it contains sulfur, and this is not good for use in a steam room – they will release harmful acids.
The main characteristics of dunite:
- Density 3.28 g / cm3
- Specific heat 0.7-0.9 kJ / kg · K
- Melting temperature over +1200 ° C
- Young’s modulus 0.89–1.95 · 105 MPa
- Poisson’s ratio 0.16-0.40
- Shear modulus 0.476-0.706 105 MPa
- Thermal conductivity 1.2–2.0 W / m · K
- Thermal diffusivity 7.2-8.6 m2 / s
The characteristics of dunite allow it to be used as a refractory stone, for example, when lining a furnace in a bath.
Important! Dunite heats up quickly, conducts heat, but also cools down quickly. For this reason, and also because of its not too presentable appearance, it is usually used in heaters as the first layer of stones.…
For heaters, dunite is sold in packs of 20 kilograms, the price is low – from 300 to 1000 rubles for such a volume, that is, from 15 rubles per kilogram. The downside is that there may be defective stones in the package, with cracks and inclusions of sulfur. Therefore, always ask for a certificate and buy stones from trusted manufacturers. In addition, after you open the package at home, review all stones to remove those that crumble or have metal inclusions, indicating the presence of sulfur.
The benefits of using dunite in baths and saunas include:
- Low price.
- Ability to withstand very high temperatures without cracking.
- No smell when heated.
- Heating occurs quickly, the stone gives off heat evenly.
- Protects against poisoning by interacting with carbon dioxide.
- It has a beneficial effect on the musculoskeletal system, strengthens the nervous system, and has a good effect on the condition of hair and skin.
There are also disadvantages of dunite in the bath:
- Serves only 6 years.
- It looks not too beautiful, ordinary cobblestone.
- There is a risk to buy a fake or a stone of low quality, cracked and interspersed with sulfur.
“Colleagues” of dunite, which can replace it in stoves or be used with it, are talcochlorite, porphyrite, gabbro, raspberry quartzite, jadeite. published by econet.ru
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