Rock wool is a fluffy, short, fine fiber material made from natural rocks such as basalt, diabase, dolomite, iron ore, bauxite, etc. It is produced by melting the rock at high temperatures, spinning it into fibers, and then compressing the fibers into dense mats or boards. Compared with other inorganic materials, rock wool has the characteristics of low density, low thermal conductivity, non-flammability, strong chemical stability, good sound absorption, wide sources, and low cost. It is widely used in heat insulation, filtration and sound insulation. Alfa Chemistry offers rock wool products to meet specific needs.
Chemical Composition
The main chemical components of rock wool are silicon dioxide, calcium oxide, aluminum oxide, magnesium oxide and trace amounts of sodium, potassium, manganese, etc. In addition, there are iron oxide (ferric oxide or ferrous oxide), and alkali metal oxides, etc., which are slightly alkaline. Because it is made at high temperature, it does not carry pathogens and has almost no ion adsorption capacity.
Properties
| Items | Description |
|---|
| Acidity coefficient (MK) | MK = (SiO2 + Al2O3) / (CaO + MgO)
Generally, the MK value is controlled in the range of 1.4-2.0. The larger the MK value, the better the temperature resistance and chemical stability of the rock wool. |
| Color | Rock wool is usually gray-green, mainly due to the strong dyeing effect of iron oxide. |
| pH Value | The PH value of rock wool is generally<4. |
| Water resistance | Rock wool has good water resistance. |
| Heat-resistant temperature | The use temperature of rock wool can be as high as 800 ℃ or above, and the softening temperature is as high as 900-1000 ℃. |
| Breathability | Rock wool has a fine pore structure with good breathability. It can convert sound energy into heat for sound absorption, thereby greatly reducing noise. |
| Corrosion resistance | Rock wool is generally made of basalt or diabase. Except for trace sulfur brought in by coke during smelting, there is no more sulfur source, so it has no corrosive effect on metals. |
| Thermal conductivity | The thermal conductivity of rock wool is 0.037-0.039 W/m·K. |
Production Process
- Sedimentation method. The main production process of the sedimentation method is that the high-temperature melt is centrifugally blown to form rock wool fibers, which are accumulated on the conveyor belt of the sedimentation chamber. After reaching a certain thickness, it passes through the pressure roller into the curing furnace, and then is cooled, cut, and packaged to make the finished product. The rock wool fibers obtained by the sedimentation method are distributed in a plane, and the uniformity of the binder is poor, which affects the compressive properties and interlayer bonding strength of the rock wool.
- Pendulum method. The pendulum method improves the cotton collection method based on the sedimentation method. It first collects the thinner rock wool layer by the capture belt, and then stacks it layer by layer by the pendulum to reach a certain number of layers and thickness. And then pressed by the pressure roller and put into the curing furnace for curing. It is then cooled, cut, and packaged to form a finished product. This method improves the uniformity of the cotton layer and the binder it contains. In addition, due to the slope generated when the cotton layer is stacked, the fibers are partially distributed vertically, so the compressive strength and interlayer bonding strength are improved.
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